diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 23ec815346..06addbecb7 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -138,7 +138,7 @@ bool try_end(Error *err)
     api_set_error(err, kErrorTypeException, "Keyboard interrupt");
     got_int = false;
   } else if (msg_list != NULL && *msg_list != NULL) {
-    int should_free;
+    bool should_free;
     char *msg = get_exception_string(*msg_list,
                                      ET_ERROR,
                                      NULL,
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 860cca582c..2bb3f0fac7 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -599,7 +599,7 @@ ArrayOf(String) nvim__get_runtime(Array pat, Boolean all, Dict(runtime) *opts, E
   if (opts->do_source) {
     for (size_t i = 0; i < res.size; i++) {
       String name = res.items[i].data.string;
-      (void)do_source(name.data, false, DOSO_NONE, NULL);
+      do_source(name.data, false, DOSO_NONE, NULL);
     }
   }
 
diff --git a/src/nvim/api/vimscript.c b/src/nvim/api/vimscript.c
index 6f3f0127d1..953bd80b0f 100644
--- a/src/nvim/api/vimscript.c
+++ b/src/nvim/api/vimscript.c
@@ -231,8 +231,8 @@ static Object _call_function(String fn, Array args, dict_T *self, Error *err)
   TRY_WRAP(err, {
     // call_func() retval is deceptive, ignore it.  Instead we set `msg_list`
     // (see above) to capture abort-causing non-exception errors.
-    (void)call_func(fn.data, (int)fn.size, &rettv, (int)args.size,
-                    vim_args, &funcexe);
+    call_func(fn.data, (int)fn.size, &rettv, (int)args.size,
+              vim_args, &funcexe);
   });
 
   if (!ERROR_SET(err)) {
diff --git a/src/nvim/arglist.c b/src/nvim/arglist.c
index a2f3aa11ca..46725bbfc2 100644
--- a/src/nvim/arglist.c
+++ b/src/nvim/arglist.c
@@ -918,7 +918,7 @@ static void arg_all_close_unused_windows(arg_all_state_T *aall)
           if (!buf_hide(buf) && buf->b_nwindows <= 1 && bufIsChanged(buf)) {
             bufref_T bufref;
             set_bufref(&bufref, buf);
-            (void)autowrite(buf, false);
+            autowrite(buf, false);
             // Check if autocommands removed the window.
             if (!win_valid(wp) || !bufref_valid(&bufref)) {
               wpnext = lastwin->w_floating ? lastwin : firstwin;  // Start all over...
@@ -1018,10 +1018,10 @@ static void arg_all_open_windows(arg_all_state_T *aall, int count)
         aall->new_curwin = curwin;
         aall->new_curtab = curtab;
       }
-      (void)do_ecmd(0, alist_name(&AARGLIST(aall->alist)[i]), NULL, NULL, ECMD_ONE,
-                    ((buf_hide(curwin->w_buffer)
-                      || bufIsChanged(curwin->w_buffer)) ? ECMD_HIDE : 0) + ECMD_OLDBUF,
-                    curwin);
+      do_ecmd(0, alist_name(&AARGLIST(aall->alist)[i]), NULL, NULL, ECMD_ONE,
+              ((buf_hide(curwin->w_buffer)
+                || bufIsChanged(curwin->w_buffer)) ? ECMD_HIDE : 0) + ECMD_OLDBUF,
+              curwin);
       if (tab_drop_empty_window && i == count - 1) {
         autocmd_no_enter++;
       }
diff --git a/src/nvim/autocmd.c b/src/nvim/autocmd.c
index a7fe6667e8..5cb9a519ea 100644
--- a/src/nvim/autocmd.c
+++ b/src/nvim/autocmd.c
@@ -530,7 +530,7 @@ bool augroup_exists(const char *name)
 }
 
 /// ":augroup {name}".
-void do_augroup(char *arg, int del_group)
+void do_augroup(char *arg, bool del_group)
 {
   if (del_group) {
     if (*arg == NUL) {
@@ -755,7 +755,7 @@ void do_autocmd(exarg_T *eap, char *arg_in, int forceit)
   char *arg = arg_in;
   char *envpat = NULL;
   char *cmd;
-  int need_free = false;
+  bool need_free = false;
   bool nested = false;
   bool once = false;
   int group;
@@ -1222,7 +1222,7 @@ void ex_doautoall(exarg_T *eap)
 
   // Execute autocommands for the current buffer last.
   if (retval == OK) {
-    (void)do_doautocmd(arg, false, &did_aucmd);
+    do_doautocmd(arg, false, &did_aucmd);
     if (call_do_modelines && did_aucmd) {
       do_modelines(0);
     }
@@ -1568,12 +1568,11 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
   bool retval = false;
   static int nesting = 0;
   char *save_cmdarg;
-  varnumber_T save_cmdbang;
   static bool filechangeshell_busy = false;
   proftime_T wait_time;
   bool did_save_redobuff = false;
   save_redo_T save_redo;
-  const bool save_KeyTyped = KeyTyped;  // NOLINT
+  const bool save_KeyTyped = KeyTyped;
 
   // Quickly return if there are no autocommands for this event or
   // autocommands are blocked.
@@ -1782,7 +1781,7 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
     patcmd.data = data;
 
     // set v:cmdarg (only when there is a matching pattern)
-    save_cmdbang = get_vim_var_nr(VV_CMDBANG);
+    varnumber_T save_cmdbang = get_vim_var_nr(VV_CMDBANG);
     if (eap != NULL) {
       save_cmdarg = set_cmdarg(eap, NULL);
       set_vim_var_nr(VV_CMDBANG, eap->forceit);
@@ -1815,7 +1814,7 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
     }
 
     if (eap != NULL) {
-      (void)set_cmdarg(NULL, save_cmdarg);
+      set_cmdarg(NULL, save_cmdarg);
       set_vim_var_nr(VV_CMDBANG, save_cmdbang);
     }
     // delete from active_apc_list
@@ -2164,7 +2163,7 @@ char *expand_get_augroup_name(expand_T *xp, int idx)
 }
 
 /// @param doautocmd  true for :doauto*, false for :autocmd
-char *set_context_in_autocmd(expand_T *xp, char *arg, int doautocmd)
+char *set_context_in_autocmd(expand_T *xp, char *arg, bool doautocmd)
 {
   // check for a group name, skip it if present
   autocmd_include_groups = false;
@@ -2478,7 +2477,7 @@ bool au_event_is_empty(event_T event)
 
 /// Scan over the events.  "*" stands for all events.
 /// true when group name was found
-static char *arg_event_skip(char *arg, int have_group)
+static char *arg_event_skip(char *arg, bool have_group)
 {
   char *pat;
   char *p;
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 24eab644a1..41ab7ae13d 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -128,7 +128,7 @@ int get_highest_fnum(void)
 /// @param read_stdin  read file from stdin, otherwise fifo
 /// @param eap  for forced 'ff' and 'fenc' or NULL
 /// @param flags  extra flags for readfile()
-static int read_buffer(int read_stdin, exarg_T *eap, int flags)
+static int read_buffer(bool read_stdin, exarg_T *eap, int flags)
 {
   int retval = OK;
   bool silent = shortmess(SHM_FILEINFO);
@@ -269,9 +269,7 @@ int open_buffer(bool read_stdin, exarg_T *eap, int flags_arg)
   if (curbuf->b_ffname != NULL) {
 #ifdef UNIX
     int save_bin = curbuf->b_p_bin;
-    int perm;
-
-    perm = os_getperm(curbuf->b_ffname);
+    int perm = os_getperm(curbuf->b_ffname);
     if (perm >= 0 && (0 || S_ISFIFO(perm)
                       || S_ISSOCK(perm)
 # ifdef OPEN_CHR_FILES
@@ -327,7 +325,7 @@ int open_buffer(bool read_stdin, exarg_T *eap, int flags_arg)
 
   // if first time loading this buffer, init b_chartab[]
   if (curbuf->b_flags & BF_NEVERLOADED) {
-    (void)buf_init_chartab(curbuf, false);
+    buf_init_chartab(curbuf, false);
     parse_cino(curbuf);
   }
 
@@ -937,8 +935,8 @@ void goto_buffer(exarg_T *eap, int start, int dir, int count)
   if (swap_exists_action == SEA_NONE) {
     swap_exists_action = SEA_DIALOG;
   }
-  (void)do_buffer(*eap->cmd == 's' ? DOBUF_SPLIT : DOBUF_GOTO,
-                  start, dir, count, eap->forceit);
+  do_buffer(*eap->cmd == 's' ? DOBUF_SPLIT : DOBUF_GOTO,
+            start, dir, count, eap->forceit);
 
   if (swap_exists_action == SEA_QUIT && *eap->cmd == 's') {
     cleanup_T cs;
@@ -1046,7 +1044,7 @@ char *do_bufdel(int command, char *arg, int addr_count, int start_bnr, int end_b
   int bnr;                        // buffer number
 
   if (addr_count == 0) {
-    (void)do_buffer(command, DOBUF_CURRENT, FORWARD, 0, forceit);
+    do_buffer(command, DOBUF_CURRENT, FORWARD, 0, forceit);
   } else {
     if (addr_count == 2) {
       if (*arg) {               // both range and argument is not allowed
@@ -1125,7 +1123,7 @@ char *do_bufdel(int command, char *arg, int addr_count, int start_bnr, int end_b
 
 /// Make the current buffer empty.
 /// Used when it is wiped out and it's the last buffer.
-static int empty_curbuf(int close_others, int forceit, int action)
+static int empty_curbuf(bool close_others, int forceit, int action)
 {
   buf_T *buf = curbuf;
 
@@ -1197,8 +1195,8 @@ int do_buffer(int action, int start, int dir, int count, int forceit)
 {
   buf_T *buf;
   buf_T *bp;
-  int unload = (action == DOBUF_UNLOAD || action == DOBUF_DEL
-                || action == DOBUF_WIPE);
+  bool unload = (action == DOBUF_UNLOAD || action == DOBUF_DEL
+                 || action == DOBUF_WIPE);
 
   switch (start) {
   case DOBUF_FIRST:
@@ -1374,9 +1372,7 @@ int do_buffer(int action, int start, int dir, int count, int forceit)
     if (au_new_curbuf.br_buf != NULL && bufref_valid(&au_new_curbuf)) {
       buf = au_new_curbuf.br_buf;
     } else if (curwin->w_jumplistlen > 0) {
-      int jumpidx;
-
-      jumpidx = curwin->w_jumplistidx - 1;
+      int jumpidx = curwin->w_jumplistidx - 1;
       if (jumpidx < 0) {
         jumpidx = curwin->w_jumplistlen - 1;
       }
@@ -1665,7 +1661,7 @@ void enter_buffer(buf_T *buf)
       need_fileinfo = true;             // display file info after redraw
     }
     // check if file changed
-    (void)buf_check_timestamp(curbuf);
+    buf_check_timestamp(curbuf);
 
     curwin->w_topline = 1;
     curwin->w_topfill = 0;
@@ -1690,12 +1686,12 @@ void enter_buffer(buf_T *buf)
   do_autochdir();
 
   if (curbuf->b_kmap_state & KEYMAP_INIT) {
-    (void)keymap_init();
+    keymap_init();
   }
   // May need to set the spell language.  Can only do this after the buffer
   // has been properly setup.
   if (!curbuf->b_help && curwin->w_p_spell && *curwin->w_s->b_p_spl != NUL) {
-    (void)parse_spelllang(curwin);
+    parse_spelllang(curwin);
   }
   curbuf->b_last_used = time(NULL);
 
@@ -1961,7 +1957,7 @@ bool curbuf_reusable(void)
 /// Free the memory for the options of a buffer.
 /// If "free_p_ff" is true also free 'fileformat', 'buftype' and
 /// 'fileencoding'.
-void free_buf_options(buf_T *buf, int free_p_ff)
+void free_buf_options(buf_T *buf, bool free_p_ff)
 {
   if (free_p_ff) {
     clear_string_option(&buf->b_p_fenc);
@@ -2224,7 +2220,7 @@ int buflist_findpat(const char *pattern, const char *pattern_end, bool unlisted,
       return -1;
     }
     char *patend = pat + strlen(pat) - 1;
-    int toggledollar = (patend > pat && *patend == '$');
+    bool toggledollar = (patend > pat && *patend == '$');
 
     // First try finding a listed buffer.  If not found and "unlisted"
     // is true, try finding an unlisted buffer.
@@ -2755,8 +2751,6 @@ linenr_T buflist_findlnum(buf_T *buf)
 void buflist_list(exarg_T *eap)
 {
   buf_T *buf = firstbuf;
-  int len;
-  int i;
 
   garray_T buflist;
   buf_T **buflist_data = NULL;
@@ -2821,21 +2815,21 @@ void buflist_list(exarg_T *eap)
     }
 
     msg_putchar('\n');
-    len = vim_snprintf(IObuff, IOSIZE - 20, "%3d%c%c%c%c%c \"%s\"",
-                       buf->b_fnum,
-                       buf->b_p_bl ? ' ' : 'u',
-                       buf == curbuf ? '%' : (curwin->w_alt_fnum == buf->b_fnum ? '#' : ' '),
-                       buf->b_ml.ml_mfp == NULL ? ' ' : (buf->b_nwindows == 0 ? 'h' : 'a'),
-                       ro_char,
-                       changed_char,
-                       NameBuff);
+    int len = vim_snprintf(IObuff, IOSIZE - 20, "%3d%c%c%c%c%c \"%s\"",
+                           buf->b_fnum,
+                           buf->b_p_bl ? ' ' : 'u',
+                           buf == curbuf ? '%' : (curwin->w_alt_fnum == buf->b_fnum ? '#' : ' '),
+                           buf->b_ml.ml_mfp == NULL ? ' ' : (buf->b_nwindows == 0 ? 'h' : 'a'),
+                           ro_char,
+                           changed_char,
+                           NameBuff);
 
     if (len > IOSIZE - 20) {
       len = IOSIZE - 20;
     }
 
     // put "line 999" in column 40 or after the file name
-    i = 40 - vim_strsize(IObuff);
+    int i = 40 - vim_strsize(IObuff);
     do {
       IObuff[len++] = ' ';
     } while (--i > 0 && len < IOSIZE - 18);
@@ -3134,7 +3128,7 @@ static bool buf_same_file_id(buf_T *buf, FileID *file_id)
 /// Print info about the current buffer.
 ///
 /// @param fullname  when non-zero print full path
-void fileinfo(int fullname, int shorthelp, int dont_truncate)
+void fileinfo(int fullname, int shorthelp, bool dont_truncate)
 {
   char *name;
   int n;
@@ -3208,7 +3202,7 @@ void fileinfo(int fullname, int shorthelp, int dont_truncate)
               (int)curwin->w_cursor.col + 1, (int)curwin->w_virtcol + 1);
   }
 
-  (void)append_arg_number(curwin, buffer, IOSIZE);
+  append_arg_number(curwin, buffer, IOSIZE);
 
   if (dont_truncate) {
     // Temporarily set msg_scroll to avoid the message being truncated.
@@ -3251,7 +3245,6 @@ void maketitle(void)
   char *title_str = NULL;
   char *icon_str = NULL;
   int maxlen = 0;
-  int len;
   char buf[IOSIZE];
 
   if (!redrawing()) {
@@ -3374,7 +3367,7 @@ void maketitle(void)
 #undef SPACE_FOR_ARGNR
     }
   }
-  int mustset = value_change(title_str, &lasttitle);
+  bool mustset = value_change(title_str, &lasttitle);
 
   if (p_icon) {
     icon_str = buf;
@@ -3394,7 +3387,7 @@ void maketitle(void)
       }
       *icon_str = NUL;
       // Truncate name at 100 bytes.
-      len = (int)strlen(buf_p);
+      int len = (int)strlen(buf_p);
       if (len > 100) {
         len -= 100;
         len += utf_cp_tail_off(buf_p, buf_p + len) + 1;
@@ -3556,16 +3549,12 @@ bool bt_prompt(buf_T *buf)
 /// Open a window for a number of buffers.
 void ex_buffer_all(exarg_T *eap)
 {
-  buf_T *buf;
   win_T *wp, *wpnext;
   int split_ret = OK;
-  bool p_ea_save;
   int open_wins = 0;
-  int r;
   linenr_T count;               // Maximum number of windows to open.
   int all;                      // When true also load inactive buffers.
   int had_tab = cmdmod.cmod_tab;
-  tabpage_T *tpnext;
 
   if (eap->addr_count == 0) {   // make as many windows as possible
     count = 9999;
@@ -3590,7 +3579,7 @@ void ex_buffer_all(exarg_T *eap)
     goto_tabpage_tp(first_tabpage, true, true);
   }
   while (true) {
-    tpnext = curtab->tp_next;
+    tabpage_T *tpnext = curtab->tp_next;
     // Try to close floating windows first
     for (wp = lastwin->w_floating ? lastwin : firstwin; wp != NULL; wp = wpnext) {
       wpnext = wp->w_floating
@@ -3635,7 +3624,7 @@ void ex_buffer_all(exarg_T *eap)
   // lastwin may be aucmd_win
   win_enter(lastwin_nofloating(), false);
   autocmd_no_leave++;
-  for (buf = firstbuf; buf != NULL && open_wins < count; buf = buf->b_next) {
+  for (buf_T *buf = firstbuf; buf != NULL && open_wins < count; buf = buf->b_next) {
     // Check if this buffer needs a window
     if ((!all && buf->b_ml.ml_mfp == NULL) || !buf->b_p_bl) {
       continue;
@@ -3665,7 +3654,7 @@ void ex_buffer_all(exarg_T *eap)
       bufref_T bufref;
       set_bufref(&bufref, buf);
       // Split the window and put the buffer in it.
-      p_ea_save = p_ea;
+      bool p_ea_save = p_ea;
       p_ea = true;                      // use space from all windows
       split_ret = win_split(0, WSP_ROOM | WSP_BELOW);
       open_wins++;
@@ -3706,7 +3695,7 @@ void ex_buffer_all(exarg_T *eap)
 
     os_breakcheck();
     if (got_int) {
-      (void)vgetc();            // only break the file loading, not the rest
+      vgetc();            // only break the file loading, not the rest
       break;
     }
     // Autocommands deleted the buffer or aborted script processing!!!
@@ -3724,8 +3713,8 @@ void ex_buffer_all(exarg_T *eap)
 
   // Close superfluous windows.
   for (wp = lastwin; open_wins > count;) {
-    r = (buf_hide(wp->w_buffer) || !bufIsChanged(wp->w_buffer)
-         || autowrite(wp->w_buffer, false) == OK) && !is_aucmd_win(wp);
+    bool r = (buf_hide(wp->w_buffer) || !bufIsChanged(wp->w_buffer)
+              || autowrite(wp->w_buffer, false) == OK) && !is_aucmd_win(wp);
     if (!win_valid(wp)) {
       // BufWrite Autocommands made the window invalid, start over
       wp = lastwin;
@@ -3798,8 +3787,8 @@ static int chk_modeline(linenr_T lnum, int flags)
   int prev = -1;
   for (s = ml_get(lnum); *s != NUL; s++) {
     if (prev == -1 || ascii_isspace(prev)) {
-      if ((prev != -1 && strncmp(s, "ex:", (size_t)3) == 0)
-          || strncmp(s, "vi:", (size_t)3) == 0) {
+      if ((prev != -1 && strncmp(s, "ex:", 3) == 0)
+          || strncmp(s, "vi:", 3) == 0) {
         break;
       }
       // Accept both "vim" and "Vim".
@@ -3864,8 +3853,8 @@ static int chk_modeline(linenr_T lnum, int flags)
     // "vi:set opt opt opt: foo" -- foo not interpreted
     // "vi:opt opt opt: foo" -- foo interpreted
     // Accept "se" for compatibility with Elvis.
-    if (strncmp(s, "set ", (size_t)4) == 0
-        || strncmp(s, "se ", (size_t)3) == 0) {
+    if (strncmp(s, "set ", 4) == 0
+        || strncmp(s, "se ", 3) == 0) {
       if (*e != ':') {                // no terminating ':'?
         break;
       }
@@ -4140,7 +4129,7 @@ int buf_open_scratch(handle_T bufnr, char *bufname)
     return FAIL;
   }
   apply_autocmds(EVENT_BUFFILEPRE, NULL, NULL, false, curbuf);
-  (void)setfname(curbuf, bufname, NULL, true);
+  setfname(curbuf, bufname, NULL, true);
   apply_autocmds(EVENT_BUFFILEPOST, NULL, NULL, false, curbuf);
   set_option_value_give_err(kOptBufhidden, STATIC_CSTR_AS_OPTVAL("hide"), OPT_LOCAL);
   set_option_value_give_err(kOptBuftype, STATIC_CSTR_AS_OPTVAL("nofile"), OPT_LOCAL);
diff --git a/src/nvim/bufwrite.c b/src/nvim/bufwrite.c
index 7f44cdfb2c..25f69094f4 100644
--- a/src/nvim/bufwrite.c
+++ b/src/nvim/bufwrite.c
@@ -186,7 +186,7 @@ static int buf_write_convert_with_iconv(struct bw_info *ip, char **bufp, int *le
     size_t save_len = tolen;
 
     // output the initial shift state sequence
-    (void)iconv(ip->bw_iconv_fd, NULL, NULL, &to, &tolen);
+    iconv(ip->bw_iconv_fd, NULL, NULL, &to, &tolen);
 
     // There is a bug in iconv() on Linux (which appears to be
     // wide-spread) which sets "to" to NULL and messes up "tolen".
@@ -378,7 +378,7 @@ static int make_bom(char *buf_in, char *name)
     return 3;
   }
   char *p = (char *)buf;
-  (void)ucs2bytes(0xfeff, &p, flags);
+  ucs2bytes(0xfeff, &p, flags);
   return (int)((uint8_t *)p - buf);
 }
 
@@ -480,8 +480,7 @@ static int buf_write_do_autocmds(buf_T *buf, char **fnamep, char **sfnamep, char
       semsg(_(e_no_matching_autocommands_for_buftype_str_buffer), curbuf->b_p_bt);
     }
 
-    if (nofile_err
-        || aborting()) {
+    if (nofile_err || aborting()) {
       // An aborting error, interrupt or exception in the
       // autocommands.
       return FAIL;
@@ -720,7 +719,7 @@ static int get_fileinfo(buf_T *buf, char *fname, bool overwriting, bool forceit,
 
 static int buf_write_make_backup(char *fname, bool append, FileInfo *file_info_old, vim_acl_T acl,
                                  int perm, unsigned bkc, bool file_readonly, bool forceit,
-                                 int *backup_copyp, char **backupp, Error_T *err)
+                                 bool *backup_copyp, char **backupp, Error_T *err)
 {
   FileInfo file_info;
   const bool no_prepend_dot = false;
@@ -897,7 +896,7 @@ static int buf_write_make_backup(char *fname, bool append, FileInfo *file_info_o
 
         // set file protection same as original file, but
         // strip s-bit.
-        (void)os_setperm(*backupp, perm & 0777);
+        os_setperm(*backupp, perm & 0777);
 
 #ifdef UNIX
         //
@@ -1134,8 +1133,8 @@ int buf_write(buf_T *buf, char *fname, char *sfname, linenr_T start, linenr_T en
   fname = sfname;
 #endif
 
-// true if writing over original
-  int overwriting = buf->b_ffname != NULL && path_fnamecmp(ffname, buf->b_ffname) == 0;
+  // true if writing over original
+  bool overwriting = buf->b_ffname != NULL && path_fnamecmp(ffname, buf->b_ffname) == 0;
 
   no_wait_return++;                 // don't wait for return yet
 
@@ -1218,7 +1217,7 @@ int buf_write(buf_T *buf, char *fname, char *sfname, linenr_T start, linenr_T en
     dobackup = false;
   }
 
-  int backup_copy = false;  // copy the original file?
+  bool backup_copy = false;  // copy the original file?
 
   // Save the value of got_int and reset it.  We don't want a previous
   // interruption cancel writing, only hitting CTRL-C while writing should
@@ -1251,7 +1250,7 @@ int buf_write(buf_T *buf, char *fname, char *sfname, linenr_T start, linenr_T en
       && file_info_old.stat.st_uid == getuid()
       && vim_strchr(p_cpo, CPO_FWRITE) == NULL) {
     perm |= 0200;
-    (void)os_setperm(fname, perm);
+    os_setperm(fname, perm);
     made_writable = true;
   }
 #endif
@@ -1278,8 +1277,7 @@ int buf_write(buf_T *buf, char *fname, char *sfname, linenr_T start, linenr_T en
   // This makes all block numbers positive so that recovery does not need
   // the original file.
   // Don't do this if there is a backup file and we are exiting.
-  if (reset_changed && !newfile && overwriting
-      && !(exiting && backup != NULL)) {
+  if (reset_changed && !newfile && overwriting && !(exiting && backup != NULL)) {
     ml_preserve(buf, false, !!p_fs);
     if (got_int) {
       err = set_err(_(e_interr));
@@ -1303,7 +1301,7 @@ int buf_write(buf_T *buf, char *fname, char *sfname, linenr_T start, linenr_T en
   }
 
   // Check if the file needs to be converted.
-  int converted = need_conversion(fenc);
+  bool converted = need_conversion(fenc);
   int wb_flags = 0;
 
   // Check if UTF-8 to UCS-2/4 or Latin1 conversion needs to be done.  Or
@@ -1367,7 +1365,7 @@ int buf_write(buf_T *buf, char *fname, char *sfname, linenr_T start, linenr_T en
   int nchars;
   linenr_T lnum;
   int fileformat;
-  int checking_conversion;
+  bool checking_conversion;
 
   int fd;
 
@@ -1605,7 +1603,7 @@ restore_backup:
 
     if (!buf->b_p_fixeol && buf->b_p_eof) {
       // write trailing CTRL-Z
-      (void)write_eintr(write_info.bw_fd, "\x1a", 1);
+      write_eintr(write_info.bw_fd, "\x1a", 1);
     }
 
     // Stop when writing done or an error was encountered.
@@ -1654,7 +1652,7 @@ restore_backup:
           || file_info.stat.st_gid != file_info_old.stat.st_gid) {
         os_fchown(fd, (uv_uid_t)file_info_old.stat.st_uid, (uv_gid_t)file_info_old.stat.st_gid);
         if (perm >= 0) {  // Set permission again, may have changed.
-          (void)os_setperm(wfname, perm);
+          os_setperm(wfname, perm);
         }
       }
       buf_set_file_id(buf);
@@ -1675,7 +1673,7 @@ restore_backup:
     }
 #endif
     if (perm >= 0) {  // Set perm. of new file same as old file.
-      (void)os_setperm(wfname, perm);
+      os_setperm(wfname, perm);
     }
     // Probably need to set the ACL before changing the user (can't set the
     // ACL on a file the user doesn't own).
diff --git a/src/nvim/change.c b/src/nvim/change.c
index 290f527946..82bb703b6f 100644
--- a/src/nvim/change.c
+++ b/src/nvim/change.c
@@ -85,7 +85,7 @@ void change_warning(buf_T *buf, int col)
     msg_puts_attr(_(w_readonly), HL_ATTR(HLF_W) | MSG_HIST);
     set_vim_var_string(VV_WARNINGMSG, _(w_readonly), -1);
     msg_clr_eos();
-    (void)msg_end();
+    msg_end();
     if (msg_silent == 0 && !silent_mode && ui_active()) {
       ui_flush();
       os_delay(1002, true);  // give the user time to think about it
@@ -184,7 +184,7 @@ static void changed_common(buf_T *buf, linenr_T lnum, colnr_T col, linenr_T lnum
     // Create a new entry if a new undo-able change was started or we
     // don't have an entry yet.
     if (buf->b_new_change || buf->b_changelistlen == 0) {
-      int add;
+      bool add;
       if (buf->b_changelistlen == 0) {
         add = true;
       } else {
@@ -567,7 +567,7 @@ void changed_lines(buf_T *buf, linenr_T lnum, colnr_T col, linenr_T lnume, linen
 /// When `ff` is true also reset 'fileformat'.
 /// When `always_inc_changedtick` is true b:changedtick is incremented even
 /// when the changed flag was off.
-void unchanged(buf_T *buf, int ff, bool always_inc_changedtick)
+void unchanged(buf_T *buf, bool ff, bool always_inc_changedtick)
 {
   if (buf->b_changed || (ff && file_ff_differs(buf, false))) {
     buf->b_changed = false;
@@ -922,8 +922,9 @@ int del_bytes(colnr_T count, bool fixpos_arg, bool use_delcombine)
 
 /// Copy the indent from ptr to the current line (and fill to size).
 /// Leaves the cursor on the first non-blank in the line.
+///
 /// @return true if the line was changed.
-int copy_indent(int size, char *src)
+bool copy_indent(int size, char *src)
 {
   char *p = NULL;
   char *line = NULL;
@@ -1053,7 +1054,7 @@ int copy_indent(int size, char *src)
 /// @param dir  FORWARD or BACKWARD
 ///
 /// @return true on success, false on failure
-int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
+bool open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
 {
   char *next_line = NULL;         // copy of the next line
   char *p_extra = NULL;           // what goes to next line
@@ -1074,7 +1075,6 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
   char saved_char = NUL;          // init for GCC
   pos_T *pos;
   bool do_si = may_do_si();
-  bool do_cindent;
   bool no_si = false;             // reset did_si afterwards
   int first_char = NUL;           // init for GCC
   int vreplace_mode;
@@ -1155,10 +1155,8 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
     //   "if (condition) {"
     if (!trunc_line && do_si && *saved_line != NUL
         && (p_extra == NULL || first_char != '{')) {
-      char *ptr;
-
       old_cursor = curwin->w_cursor;
-      ptr = saved_line;
+      char *ptr = saved_line;
       if (flags & OPENLINE_DO_COM) {
         lead_len = get_leader_len(ptr, NULL, false, true);
       } else {
@@ -1288,9 +1286,9 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
   }
 
   // May do indenting after opening a new line.
-  do_cindent = !p_paste && (curbuf->b_p_cin || *curbuf->b_p_inde != NUL)
-               && in_cinkeys(dir == FORWARD ? KEY_OPEN_FORW : KEY_OPEN_BACK,
-                             ' ', linewhite(curwin->w_cursor.lnum));
+  bool do_cindent = !p_paste && (curbuf->b_p_cin || *curbuf->b_p_inde != NUL)
+                    && in_cinkeys(dir == FORWARD ? KEY_OPEN_FORW : KEY_OPEN_BACK,
+                                  ' ', linewhite(curwin->w_cursor.lnum));
 
   // Find out if the current line starts with a comment leader.
   // This may then be inserted in front of the new line.
@@ -1321,7 +1319,6 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
     char lead_end[COM_MAX_LEN];             // end-comment string
     char *comment_end = NULL;               // where lead_end has been found
     int extra_space = false;                // append extra space
-    int current_flag;
     bool require_blank = false;             // requires blank after middle
     char *p2;
 
@@ -1333,7 +1330,7 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
         continue;
       }
       if (*p == COM_START || *p == COM_MIDDLE) {
-        current_flag = (unsigned char)(*p);
+        int current_flag = (unsigned char)(*p);
         if (*p == COM_START) {
           // Doing "O" on a start of comment does not insert leader.
           if (dir == BACKWARD) {
@@ -1342,7 +1339,7 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
           }
 
           // find start of middle part
-          (void)copy_option_part(&p, lead_middle, COM_MAX_LEN, ",");
+          copy_option_part(&p, lead_middle, COM_MAX_LEN, ",");
           require_blank = false;
         }
 
@@ -1353,7 +1350,7 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
           }
           p++;
         }
-        (void)copy_option_part(&p, lead_middle, COM_MAX_LEN, ",");
+        copy_option_part(&p, lead_middle, COM_MAX_LEN, ",");
 
         while (*p && p[-1] != ':') {  // find end of end flags
           // Check whether we allow automatic ending of comments
@@ -1498,13 +1495,12 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
             int repl_size = vim_strnsize(lead_repl, lead_repl_len);
             int old_size = 0;
             char *endp = p;
-            int l;
 
             while (old_size < repl_size && p > leader) {
               MB_PTR_BACK(leader, p);
               old_size += ptr2cells(p);
             }
-            l = lead_repl_len - (int)(endp - p);
+            int l = lead_repl_len - (int)(endp - p);
             if (l != 0) {
               memmove(endp + l, endp,
                       (size_t)((leader + lead_len) - endp));
@@ -1731,7 +1727,7 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
     if (curwin->w_cursor.lnum >= Insstart.lnum + vr_lines_changed) {
       // In case we NL to a new line, BS to the previous one, and NL
       // again, we don't want to save the new line for undo twice.
-      (void)u_save_cursor();  // errors are ignored!
+      u_save_cursor();  // errors are ignored!
       vr_lines_changed++;
     }
     ml_replace(curwin->w_cursor.lnum, p_extra, true);
@@ -1754,14 +1750,14 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
     }
     // Copy the indent
     if (curbuf->b_p_ci) {
-      (void)copy_indent(newindent, saved_line);
+      copy_indent(newindent, saved_line);
 
       // Set the 'preserveindent' option so that any further screwing
       // with the line doesn't entirely destroy our efforts to preserve
       // it.  It gets restored at the function end.
       curbuf->b_p_pi = true;
     } else {
-      (void)set_indent(newindent, SIN_INSERT|SIN_NOMARK);
+      set_indent(newindent, SIN_INSERT|SIN_NOMARK);
     }
     less_cols -= curwin->w_cursor.col;
 
@@ -2002,7 +1998,7 @@ int get_leader_len(char *line, char **flags, bool backward, bool include_space)
         *flags = list;              // remember where flags started
       }
       char *prev_list = list;
-      (void)copy_option_part(&list, part_buf, COM_MAX_LEN, ",");
+      copy_option_part(&list, part_buf, COM_MAX_LEN, ",");
       string = vim_strchr(part_buf, ':');
       if (string == NULL) {         // missing ':', ignore this part
         continue;
@@ -2135,7 +2131,7 @@ int get_last_leader_offset(char *line, char **flags)
 
       // Get one option part into part_buf[].  Advance list to next one.
       // put string at start of string.
-      (void)copy_option_part(&list, part_buf, COM_MAX_LEN, ",");
+      copy_option_part(&list, part_buf, COM_MAX_LEN, ",");
       char *string = vim_strchr(part_buf, ':');
       if (string == NULL) {  // If everything is fine, this cannot actually
                              // happen.
@@ -2217,7 +2213,7 @@ int get_last_leader_offset(char *line, char **flags)
       for (char *list = curbuf->b_p_com; *list;) {
         char *flags_save = list;
 
-        (void)copy_option_part(&list, part_buf2, COM_MAX_LEN, ",");
+        copy_option_part(&list, part_buf2, COM_MAX_LEN, ",");
         if (flags_save == com_flags) {
           continue;
         }
diff --git a/src/nvim/charset.c b/src/nvim/charset.c
index fc900fd3a7..82a2a3bfe7 100644
--- a/src/nvim/charset.c
+++ b/src/nvim/charset.c
@@ -85,7 +85,7 @@ int init_chartab(void)
 ///
 /// @return FAIL if 'iskeyword', 'isident', 'isfname' or 'isprint' option has
 /// an error, OK otherwise.
-int buf_init_chartab(buf_T *buf, int global)
+int buf_init_chartab(buf_T *buf, bool global)
 {
   int c;
 
@@ -490,7 +490,7 @@ char *str_foldcase(char *str, int orglen, char *buf, int buflen)
           }
         }
       }
-      (void)utf_char2bytes(lc, STR_PTR(i));
+      utf_char2bytes(lc, STR_PTR(i));
     }
 
     // skip to next multi-byte char
@@ -1446,9 +1446,9 @@ bool rem_backslash(const char *str)
                  && str[1] != '?'
                  && !vim_isfilec((uint8_t)str[1])));
 
-#else  // ifdef BACKSLASH_IN_FILENAME
+#else
   return str[0] == '\\' && str[1] != NUL;
-#endif  // ifdef BACKSLASH_IN_FILENAME
+#endif
 }
 
 /// Halve the number of backslashes in a file name argument.
diff --git a/src/nvim/cmdexpand.c b/src/nvim/cmdexpand.c
index 3198156409..12335bc22f 100644
--- a/src/nvim/cmdexpand.c
+++ b/src/nvim/cmdexpand.c
@@ -73,7 +73,7 @@ typedef void *(*user_expand_func_T)(const char *, int, typval_T *);
 # include "cmdexpand.c.generated.h"
 #endif
 
-static int cmd_showtail;  ///< Only show path tail in lists ?
+static bool cmd_showtail;  ///< Only show path tail in lists ?
 
 /// "compl_match_array" points the currently displayed list of entries in the
 /// popup menu.  It is NULL when there is no popup menu.
@@ -325,7 +325,7 @@ int nextwild(expand_T *xp, int type, int options, bool escape)
     beep_flush();
   } else if (xp->xp_numfiles == 1) {
     // free expanded pattern
-    (void)ExpandOne(xp, NULL, NULL, 0, WILD_FREE);
+    ExpandOne(xp, NULL, NULL, 0, WILD_FREE);
   }
 
   return OK;
@@ -334,7 +334,7 @@ int nextwild(expand_T *xp, int type, int options, bool escape)
 /// Create and display a cmdline completion popup menu with items from
 /// "matches".
 static int cmdline_pum_create(CmdlineInfo *ccline, expand_T *xp, char **matches, int numMatches,
-                              int showtail)
+                              bool showtail)
 {
   assert(numMatches >= 0);
   // Add all the completion matches
@@ -441,7 +441,7 @@ static int wildmenu_match_len(expand_T *xp, char *s)
 /// If inversion is possible we use it. Else '=' characters are used.
 ///
 /// @param matches  list of matches
-static void redraw_wildmenu(expand_T *xp, int num_matches, char **matches, int match, int showtail)
+static void redraw_wildmenu(expand_T *xp, int num_matches, char **matches, int match, bool showtail)
 {
   int len;
   int clen;                     // length in screen cells
@@ -964,7 +964,7 @@ void ExpandCleanup(expand_T *xp)
 /// @param showtail     display only the tail of the full path of a file name
 /// @param dir_attr     highlight attribute to use for directory names
 static void showmatches_oneline(expand_T *xp, char **matches, int numMatches, int lines, int linenr,
-                                int maxlen, int showtail, int dir_attr)
+                                int maxlen, bool showtail, int dir_attr)
 {
   char *p;
   int lastlen = 999;
@@ -1023,7 +1023,7 @@ static void showmatches_oneline(expand_T *xp, char **matches, int numMatches, in
 /// Show all matches for completion on the command line.
 /// Returns EXPAND_NOTHING when the character that triggered expansion should
 /// be inserted like a normal character.
-int showmatches(expand_T *xp, int wildmenu)
+int showmatches(expand_T *xp, bool wildmenu)
 {
   CmdlineInfo *const ccline = get_cmdline_info();
   int numMatches;
@@ -1032,8 +1032,7 @@ int showmatches(expand_T *xp, int wildmenu)
   int maxlen;
   int lines;
   int columns;
-  int attr;
-  int showtail;
+  bool showtail;
 
   if (xp->xp_numfiles == -1) {
     set_expand_context(xp);
@@ -1102,7 +1101,7 @@ int showmatches(expand_T *xp, int wildmenu)
       lines = (numMatches + columns - 1) / columns;
     }
 
-    attr = HL_ATTR(HLF_D);      // find out highlighting for directories
+    int attr = HL_ATTR(HLF_D);      // find out highlighting for directories
 
     if (xp->xp_context == EXPAND_TAGS_LISTFILES) {
       msg_puts_attr(_("tagname"), HL_ATTR(HLF_T));
@@ -3244,7 +3243,7 @@ void globpath(char *path, char *file, garray_T *ga, int expand_options, bool dir
 
       char **p;
       int num_p = 0;
-      (void)ExpandFromContext(&xpc, buf, &p, &num_p, WILD_SILENT | expand_options);
+      ExpandFromContext(&xpc, buf, &p, &num_p, WILD_SILENT | expand_options);
       if (num_p > 0) {
         ExpandEscape(&xpc, buf, num_p, p, WILD_SILENT | expand_options);
 
@@ -3264,7 +3263,7 @@ void globpath(char *path, char *file, garray_T *ga, int expand_options, bool dir
 }
 
 /// Translate some keys pressed when 'wildmenu' is used.
-int wildmenu_translate_key(CmdlineInfo *cclp, int key, expand_T *xp, int did_wild_list)
+int wildmenu_translate_key(CmdlineInfo *cclp, int key, expand_T *xp, bool did_wild_list)
 {
   int c = key;
 
diff --git a/src/nvim/cursor.c b/src/nvim/cursor.c
index d25566213c..10b8a58ef4 100644
--- a/src/nvim/cursor.c
+++ b/src/nvim/cursor.c
@@ -291,7 +291,7 @@ linenr_T get_cursor_rel_lnum(win_T *wp, linenr_T lnum)
   // Loop until we reach to_line, skipping folds.
   for (; from_line < to_line; from_line++, retval++) {
     // If from_line is in a fold, set it to the last line of that fold.
-    (void)hasFoldingWin(wp, from_line, NULL, &from_line, true, NULL);
+    hasFoldingWin(wp, from_line, NULL, &from_line, true, NULL);
   }
 
   // If to_line is in a closed fold, the line count is off by +1. Correct it.
diff --git a/src/nvim/cursor_shape.c b/src/nvim/cursor_shape.c
index 64cf1ea263..7461dc7288 100644
--- a/src/nvim/cursor_shape.c
+++ b/src/nvim/cursor_shape.c
@@ -101,15 +101,9 @@ Array mode_style_array(Arena *arena)
 /// @returns error message for an illegal option, NULL otherwise.
 const char *parse_shape_opt(int what)
 {
-  char *colonp;
-  char *commap;
-  char *slashp;
   char *p = NULL;
-  char *endp;
   int idx = 0;                          // init for GCC
-  int all_idx;
   int len;
-  int i;
   bool found_ve = false;                 // found "ve" flag
 
   // First round: check for errors; second round: do it for real.
@@ -126,8 +120,8 @@ const char *parse_shape_opt(int what)
     // Repeat for all comma separated parts.
     char *modep = p_guicursor;
     while (modep != NULL && *modep != NUL) {
-      colonp = vim_strchr(modep, ':');
-      commap = vim_strchr(modep, ',');
+      char *colonp = vim_strchr(modep, ':');
+      char *commap = vim_strchr(modep, ',');
 
       if (colonp == NULL || (commap != NULL && commap < colonp)) {
         return N_("E545: Missing colon");
@@ -138,7 +132,7 @@ const char *parse_shape_opt(int what)
 
       // Repeat for all modes before the colon.
       // For the 'a' mode, we loop to handle all the modes.
-      all_idx = -1;
+      int all_idx = -1;
       while (modep < colonp || all_idx >= 0) {
         if (all_idx < 0) {
           // Find the mode
@@ -175,7 +169,7 @@ const char *parse_shape_opt(int what)
         for (p = colonp + 1; *p && *p != ',';) {
           {
             // First handle the ones with a number argument.
-            i = (uint8_t)(*p);
+            int i = (uint8_t)(*p);
             len = 0;
             if (STRNICMP(p, "ver", 3) == 0) {
               len = 3;
@@ -221,7 +215,7 @@ const char *parse_shape_opt(int what)
               }
               p += 5;
             } else {          // must be a highlight group name then
-              endp = vim_strchr(p, '-');
+              char *endp = vim_strchr(p, '-');
               if (commap == NULL) {                       // last part
                 if (endp == NULL) {
                   endp = p + strlen(p);                  // find end of part
@@ -229,7 +223,7 @@ const char *parse_shape_opt(int what)
               } else if (endp > commap || endp == NULL) {
                 endp = commap;
               }
-              slashp = vim_strchr(p, '/');
+              char *slashp = vim_strchr(p, '/');
               if (slashp != NULL && slashp < endp) {
                 // "group/langmap_group"
                 i = syn_check_group(p, (size_t)(slashp - p));
diff --git a/src/nvim/debugger.c b/src/nvim/debugger.c
index 35333e4b12..e41ba9fb54 100644
--- a/src/nvim/debugger.c
+++ b/src/nvim/debugger.c
@@ -285,7 +285,7 @@ void do_debug(char *cmd)
       // don't debug this command
       n = debug_break_level;
       debug_break_level = -1;
-      (void)do_cmdline(cmdline, getexline, NULL, DOCMD_VERBOSE|DOCMD_EXCRESET);
+      do_cmdline(cmdline, getexline, NULL, DOCMD_VERBOSE|DOCMD_EXCRESET);
       debug_break_level = n;
     }
     lines_left = Rows - 1;
@@ -408,7 +408,7 @@ static linenr_T debug_breakpoint_lnum;
 /// debug_skipped_name is then set to the source name in the breakpoint case. If
 /// a skipped command decides itself that a debug prompt should be displayed, it
 /// can do so by calling dbg_check_skipped().
-static int debug_skipped;
+static bool debug_skipped;
 static char *debug_skipped_name;
 
 /// Go to debug mode when a breakpoint was encountered or "ex_nesting_level" is
@@ -463,7 +463,7 @@ bool dbg_check_skipped(exarg_T *eap)
 
   // Save the value of got_int and reset it.  We don't want a previous
   // interruption cause flushing the input buffer.
-  int prev_got_int = got_int;
+  bool prev_got_int = got_int;
   got_int = false;
   debug_breakpoint_name = debug_skipped_name;
   // eap->skip is true
@@ -788,7 +788,6 @@ static linenr_T debuggy_find(bool file, char *fname, linenr_T after, garray_T *g
   struct debuggy *bp;
   linenr_T lnum = 0;
   char *name = fname;
-  int prev_got_int;
 
   // Return quickly when there are no breakpoints.
   if (GA_EMPTY(gap)) {
@@ -813,7 +812,7 @@ static linenr_T debuggy_find(bool file, char *fname, linenr_T after, garray_T *g
       // Save the value of got_int and reset it.  We don't want a
       // previous interruption cancel matching, only hitting CTRL-C
       // while matching should abort it.
-      prev_got_int = got_int;
+      bool prev_got_int = got_int;
       got_int = false;
       if (vim_regexec_prog(&bp->dbg_prog, false, name, 0)) {
         lnum = bp->dbg_lnum;
diff --git a/src/nvim/decoration.c b/src/nvim/decoration.c
index 02b95576ea..95b1443931 100644
--- a/src/nvim/decoration.c
+++ b/src/nvim/decoration.c
@@ -826,7 +826,7 @@ static void buf_signcols_validate_range(buf_T *buf, int row1, int row2, int add)
   int *overlap = xcalloc(sizeof(int), (size_t)(row2 + 1 - row1));
 
   // First find the number of overlapping signs at "row1".
-  (void)marktree_itr_get_overlap(buf->b_marktree, currow, 0, itr);
+  marktree_itr_get_overlap(buf->b_marktree, currow, 0, itr);
   while (marktree_itr_step_overlap(buf->b_marktree, itr, &pair)) {
     if (!mt_invalid(pair.start) && pair.start.flags & MT_FLAG_DECOR_SIGNTEXT) {
       overlap[0]++;
diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index 765cbdadd2..3e62555fac 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -1012,7 +1012,7 @@ static int check_external_diff(diffio_T *diffio)
     if (fd == NULL) {
       io_error = true;
     } else {
-      if (fwrite("line1\n", (size_t)6, (size_t)1, fd) != 1) {
+      if (fwrite("line1\n", 6, 1, fd) != 1) {
         io_error = true;
       }
       fclose(fd);
@@ -1021,7 +1021,7 @@ static int check_external_diff(diffio_T *diffio)
       if (fd == NULL) {
         io_error = true;
       } else {
-        if (fwrite("line2\n", (size_t)6, (size_t)1, fd) != 1) {
+        if (fwrite("line2\n", 6, 1, fd) != 1) {
           io_error = true;
         }
         fclose(fd);
@@ -1166,9 +1166,9 @@ static int diff_file(diffio_T *dio)
                tmp_orig, tmp_new);
   append_redir(cmd, len, p_srr, tmp_diff);
   block_autocmds();  // Avoid ShellCmdPost stuff
-  (void)call_shell(cmd,
-                   kShellOptFilter | kShellOptSilent | kShellOptDoOut,
-                   NULL);
+  call_shell(cmd,
+             kShellOptFilter | kShellOptSilent | kShellOptDoOut,
+             NULL);
   unblock_autocmds();
   xfree(cmd);
   return OK;
@@ -1250,7 +1250,7 @@ void ex_diffpatch(exarg_T *eap)
     vim_snprintf(buf, buflen, "patch -o %s %s < %s",
                  tmp_new, tmp_orig, esc_name);
     block_autocmds();  // Avoid ShellCmdPost stuff
-    (void)call_shell(buf, kShellOptFilter, NULL);
+    call_shell(buf, kShellOptFilter, NULL);
     unblock_autocmds();
   }
 
@@ -1398,7 +1398,7 @@ static void set_diff_option(win_T *wp, bool value)
 /// Set options in window "wp" for diff mode.
 ///
 /// @param addbuf Add buffer to diff.
-void diff_win_options(win_T *wp, int addbuf)
+void diff_win_options(win_T *wp, bool addbuf)
 {
   win_T *old_curwin = curwin;
 
@@ -1888,7 +1888,7 @@ static void count_filler_lines_and_topline(int *curlinenum_to, int *linesfiller,
 {
   const diff_T *curdif = thistopdiff;
   int ch_virtual_lines = 0;
-  int isfiller = 0;
+  bool isfiller = false;
   while (virtual_lines_passed > 0) {
     if (ch_virtual_lines) {
       virtual_lines_passed--;
@@ -1901,7 +1901,7 @@ static void count_filler_lines_and_topline(int *curlinenum_to, int *linesfiller,
     } else {
       (*linesfiller) = 0;
       ch_virtual_lines = get_max_diff_length(curdif);
-      isfiller = (curdif->df_count[toidx] ? 0 : 1);
+      isfiller = (curdif->df_count[toidx] ? false : true);
       if (isfiller) {
         while (curdif && curdif->df_next && curdif->df_lnum[toidx] ==
                curdif->df_next->df_lnum[toidx]
@@ -2444,8 +2444,8 @@ void diff_set_topline(win_T *fromwin, win_T *towin)
   changed_line_abv_curs_win(towin);
 
   check_topfill(towin, false);
-  (void)hasFoldingWin(towin, towin->w_topline, &towin->w_topline,
-                      NULL, true, NULL);
+  hasFoldingWin(towin, towin->w_topline, &towin->w_topline,
+                NULL, true, NULL);
 }
 
 /// This is called when 'diffopt' is changed.
diff --git a/src/nvim/digraph.c b/src/nvim/digraph.c
index 6b3c4e902b..991b82f295 100644
--- a/src/nvim/digraph.c
+++ b/src/nvim/digraph.c
@@ -2042,13 +2042,10 @@ char *keymap_init(void)
     keymap_unload();
     do_cmdline_cmd("unlet! b:keymap_name");
   } else {
-    char *buf;
-    size_t buflen;
-
     // Source the keymap file.  It will contain a ":loadkeymap" command
     // which will call ex_loadkeymap() below.
-    buflen = strlen(curbuf->b_p_keymap) + strlen(p_enc) + 14;
-    buf = xmalloc(buflen);
+    size_t buflen = strlen(curbuf->b_p_keymap) + strlen(p_enc) + 14;
+    char *buf = xmalloc(buflen);
 
     // try finding "keymap/'keymap'_'encoding'.vim"  in 'runtimepath'
     vim_snprintf(buf, buflen, "keymap/%s_%s.vim",
@@ -2130,7 +2127,7 @@ void ex_loadkeymap(exarg_T *eap)
     vim_snprintf(buf, sizeof(buf), "<buffer> %s %s",
                  ((kmap_T *)curbuf->b_kmap_ga.ga_data)[i].from,
                  ((kmap_T *)curbuf->b_kmap_ga.ga_data)[i].to);
-    (void)do_map(MAPTYPE_MAP, buf, MODE_LANGMAP, false);
+    do_map(MAPTYPE_MAP, buf, MODE_LANGMAP, false);
   }
 
   p_cpo = save_cpo;
@@ -2167,7 +2164,7 @@ static void keymap_unload(void)
 
   for (int i = 0; i < curbuf->b_kmap_ga.ga_len; i++) {
     vim_snprintf(buf, sizeof(buf), "<buffer> %s", kp[i].from);
-    (void)do_map(MAPTYPE_UNMAP, buf, MODE_LANGMAP, false);
+    do_map(MAPTYPE_UNMAP, buf, MODE_LANGMAP, false);
   }
   keymap_ga_clear(&curbuf->b_kmap_ga);
 
@@ -2193,13 +2190,12 @@ bool get_keymap_str(win_T *wp, char *fmt, char *buf, int len)
 
   buf_T *old_curbuf = curbuf;
   win_T *old_curwin = curwin;
-  char *s;
 
   curbuf = wp->w_buffer;
   curwin = wp;
   STRCPY(buf, "b:keymap_name");       // must be writable
   emsg_skip++;
-  s = p = eval_to_string(buf, false);
+  char *s = p = eval_to_string(buf, false);
   emsg_skip--;
   curbuf = old_curbuf;
   curwin = old_curwin;
diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 4b14a3a1ee..9d870de7d9 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -935,7 +935,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
   int spell_attr = 0;                   // attributes desired by spelling
   int word_end = 0;                     // last byte with same spell_attr
   int cur_checked_col = 0;              // checked column for current line
-  int extra_check = 0;                  // has syntax or linebreak
+  bool extra_check = 0;                 // has syntax or linebreak
   int multi_attr = 0;                   // attributes desired by multibyte
   int mb_l = 1;                         // multi-byte byte length
   int mb_c = 0;                         // decoded multi-byte character
@@ -2158,7 +2158,6 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
           if (!wp->w_p_lbr || !wp->w_p_list) {
             wlv.n_extra = tab_len;
           } else {
-            char *p;
             int saved_nextra = wlv.n_extra;
 
             if (wlv.vcol_off > 0) {
@@ -2184,7 +2183,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
                 len += wlv.n_extra - tab_len;
               }
               mb_c = wp->w_p_lcs_chars.tab1;
-              p = get_extra_buf((size_t)len + 1);
+              char *p = get_extra_buf((size_t)len + 1);
               memset(p, ' ', (size_t)len);
               p[len] = NUL;
               wlv.p_extra = p;
@@ -2293,10 +2292,8 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
           wlv.c_extra = NUL;
           wlv.c_final = NUL;
           if (wp->w_p_lbr) {
-            char *p;
-
             mb_c = (uint8_t)(*wlv.p_extra);
-            p = get_extra_buf((size_t)wlv.n_extra + 1);
+            char *p = get_extra_buf((size_t)wlv.n_extra + 1);
             memset(p, ' ', (size_t)wlv.n_extra);
             memcpy(p, wlv.p_extra + 1, strlen(wlv.p_extra) - 1);
             p[wlv.n_extra] = NUL;
diff --git a/src/nvim/drawscreen.c b/src/nvim/drawscreen.c
index 9e3f96d2c2..9dec2ce1e3 100644
--- a/src/nvim/drawscreen.c
+++ b/src/nvim/drawscreen.c
@@ -442,7 +442,7 @@ int update_screen(void)
   // will be redrawn later or in win_update().
   must_redraw = 0;
 
-  updating_screen = 1;
+  updating_screen = true;
 
   display_tick++;  // let syntax code know we're in a next round of
                    // display updating
@@ -655,7 +655,7 @@ int update_screen(void)
     wp->w_buffer->b_signcols.resized = false;
   }
 
-  updating_screen = 0;
+  updating_screen = false;
 
   // Clear or redraw the command line.  Done last, because scrolling may
   // mess up the command line.
@@ -917,11 +917,11 @@ int showmode(void)
 
   msg_grid_validate();
 
-  int do_mode = ((p_smd && msg_silent == 0)
-                 && ((State & MODE_TERMINAL)
-                     || (State & MODE_INSERT)
-                     || restart_edit != NUL
-                     || VIsual_active));
+  bool do_mode = ((p_smd && msg_silent == 0)
+                  && ((State & MODE_TERMINAL)
+                      || (State & MODE_INSERT)
+                      || restart_edit != NUL
+                      || VIsual_active));
 
   bool can_show_mode = (p_ch != 0 || ui_has(kUIMessages));
   if ((do_mode || reg_recording != 0) && can_show_mode) {
@@ -1608,14 +1608,14 @@ static void win_update(win_T *wp)
         }
       }
 
-      (void)hasFoldingWin(wp, mod_top, &mod_top, NULL, true, NULL);
+      hasFoldingWin(wp, mod_top, &mod_top, NULL, true, NULL);
       if (mod_top > lnumt) {
         mod_top = lnumt;
       }
 
       // Now do the same for the bottom line (one above mod_bot).
       mod_bot--;
-      (void)hasFoldingWin(wp, mod_bot, NULL, &mod_bot, true, NULL);
+      hasFoldingWin(wp, mod_bot, NULL, &mod_bot, true, NULL);
       mod_bot++;
       if (mod_bot < lnumb) {
         mod_bot = lnumb;
@@ -1686,17 +1686,15 @@ static void win_update(win_T *wp)
       // New topline is above old topline: May scroll down.
       int j;
       if (hasAnyFolding(wp)) {
-        linenr_T ln;
-
         // count the number of lines we are off, counting a sequence
         // of folded lines as one
         j = 0;
-        for (ln = wp->w_topline; ln < wp->w_lines[0].wl_lnum; ln++) {
+        for (linenr_T ln = wp->w_topline; ln < wp->w_lines[0].wl_lnum; ln++) {
           j++;
           if (j >= wp->w_grid.rows - 2) {
             break;
           }
-          (void)hasFoldingWin(wp, ln, NULL, &ln, true, NULL);
+          hasFoldingWin(wp, ln, NULL, &ln, true, NULL);
         }
       } else {
         j = wp->w_lines[0].wl_lnum - wp->w_topline;
@@ -2318,7 +2316,7 @@ static void win_update(win_T *wp)
         // text doesn't need to be drawn, but the number column does.
         foldinfo_T info = wp->w_p_cul && lnum == wp->w_cursor.lnum
                           ? cursorline_fi : fold_info(wp, lnum);
-        (void)win_line(wp, lnum, srow, wp->w_grid.rows, true, &spv, info);
+        win_line(wp, lnum, srow, wp->w_grid.rows, true, &spv, info);
       }
 
       // This line does not need to be drawn, advance to the next one.
diff --git a/src/nvim/drawscreen.h b/src/nvim/drawscreen.h
index b18a907ba8..1f6f41fae2 100644
--- a/src/nvim/drawscreen.h
+++ b/src/nvim/drawscreen.h
@@ -19,7 +19,7 @@ enum {
 
 /// While redrawing the screen this flag is set.  It means the screen size
 /// ('lines' and 'rows') must not be changed.
-EXTERN bool updating_screen INIT( = 0);
+EXTERN bool updating_screen INIT( = false);
 
 EXTERN match_T screen_search_hl INIT( = { 0 });  ///< used for 'hlsearch' highlight matching
 
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index 8984a959d3..80e6648e95 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -112,7 +112,7 @@ static int did_restart_edit;            // "restart_edit" when calling edit()
 
 static bool can_cindent;                // may do cindenting on this line
 
-static int revins_on;                   // reverse insert mode on
+static bool revins_on;                  // reverse insert mode on
 static int revins_chars;                // how much to skip after edit
 static int revins_legal;                // was the last char 'legal'?
 static int revins_scol;                 // start column of revins session
@@ -1598,7 +1598,7 @@ void undisplay_dollar(void)
 /// @param round               if true, round the indent to 'shiftwidth' (only with _INC and _Dec).
 /// @param replaced            replaced character, put on replace stack
 /// @param call_changed_bytes  call changed_bytes()
-void change_indent(int type, int amount, int round, int replaced, int call_changed_bytes)
+void change_indent(int type, int amount, int round, int replaced, bool call_changed_bytes)
 {
   int insstart_less;                    // reduction for Insstart.col
   colnr_T orig_col = 0;                 // init for GCC
@@ -1640,7 +1640,7 @@ void change_indent(int type, int amount, int round, int replaced, int call_chang
 
   // Set the new indent.  The cursor will be put on the first non-blank.
   if (type == INDENT_SET) {
-    (void)set_indent(amount, call_changed_bytes ? SIN_CHANGED : 0);
+    set_indent(amount, call_changed_bytes ? SIN_CHANGED : 0);
   } else {
     int save_State = State;
 
@@ -2138,11 +2138,10 @@ void insertchar(int c, int flags, int second_indent)
       && !p_ri) {
 #define INPUT_BUFLEN 100
     char buf[INPUT_BUFLEN + 1];
-    int i;
     colnr_T virtcol = 0;
 
     buf[0] = (char)c;
-    i = 1;
+    int i = 1;
     if (textwidth > 0) {
       virtcol = get_nolist_virtcol();
     }
@@ -2456,9 +2455,7 @@ void beginline(int flags)
     curwin->w_cursor.coladd = 0;
 
     if (flags & (BL_WHITE | BL_SOL)) {
-      char *ptr;
-
-      for (ptr = get_cursor_line_ptr(); ascii_iswhite(*ptr)
+      for (char *ptr = get_cursor_line_ptr(); ascii_iswhite(*ptr)
            && !((flags & BL_FIX) && ptr[1] == NUL); ptr++) {
         curwin->w_cursor.col++;
       }
@@ -2571,7 +2568,7 @@ void cursor_up_inner(win_T *wp, linenr_T n)
     // Count each sequence of folded lines as one logical line.
 
     // go to the start of the current fold
-    (void)hasFoldingWin(wp, lnum, &lnum, NULL, true, NULL);
+    hasFoldingWin(wp, lnum, &lnum, NULL, true, NULL);
 
     while (n--) {
       // move up one line
@@ -2583,7 +2580,7 @@ void cursor_up_inner(win_T *wp, linenr_T n)
       // Insert mode or when 'foldopen' contains "all": it will open
       // in a moment.
       if (n > 0 || !((State & MODE_INSERT) || (fdo_flags & FDO_ALL))) {
-        (void)hasFoldingWin(wp, lnum, &lnum, NULL, true, NULL);
+        hasFoldingWin(wp, lnum, &lnum, NULL, true, NULL);
       }
     }
     if (lnum < 1) {
@@ -2597,7 +2594,7 @@ void cursor_up_inner(win_T *wp, linenr_T n)
 }
 
 /// @param upd_topline  When true: update topline
-int cursor_up(linenr_T n, int upd_topline)
+int cursor_up(linenr_T n, bool upd_topline)
 {
   // This fails if the cursor is already in the first line.
   if (n > 0 && curwin->w_cursor.lnum <= 1) {
@@ -2650,7 +2647,7 @@ void cursor_down_inner(win_T *wp, int n)
 }
 
 /// @param upd_topline  When true: update topline
-int cursor_down(int n, int upd_topline)
+int cursor_down(int n, bool upd_topline)
 {
   // This fails if the cursor is already in the last line.
   if (n > 0 && curwin->w_cursor.lnum >= curwin->w_buffer->b_ml.ml_line_count) {
@@ -2947,7 +2944,7 @@ static void replace_do_bs(int limit_col)
       getvcol(curwin, &curwin->w_cursor, NULL, &start_vcol, NULL);
       orig_vcols = win_chartabsize(curwin, get_cursor_pos_ptr(), start_vcol);
     }
-    (void)del_char_after_col(limit_col);
+    del_char_after_col(limit_col);
     if (l_State & VREPLACE_FLAG) {
       orig_len = (int)strlen(get_cursor_pos_ptr());
     }
@@ -2978,7 +2975,7 @@ static void replace_do_bs(int limit_col)
     // mark the buffer as changed and prepare for displaying
     changed_bytes(curwin->w_cursor.lnum, curwin->w_cursor.col);
   } else if (cc == 0) {
-    (void)del_char_after_col(limit_col);
+    del_char_after_col(limit_col);
   }
 }
 
@@ -3005,8 +3002,8 @@ bool cindent_on(void)
 bool in_cinkeys(int keytyped, int when, bool line_is_empty)
 {
   char *look;
-  int try_match;
-  int try_match_word;
+  bool try_match;
+  bool try_match_word;
   char *p;
   bool icase;
 
@@ -3412,7 +3409,7 @@ static bool ins_esc(int *count, int cmdchar, bool nomove)
         State &= ~REPLACE_FLAG;
       }
 
-      (void)start_redo_ins();
+      start_redo_ins();
       if (cmdchar == 'r' || cmdchar == 'v') {
         stuffRedoReadbuff(ESC_STR);  // No ESC in redo buffer
       }
@@ -3602,7 +3599,7 @@ static void ins_shift(int c, int lastc)
   if (c == Ctrl_D && (lastc == '0' || lastc == '^')
       && curwin->w_cursor.col > 0) {
     curwin->w_cursor.col--;
-    (void)del_char(false);              // delete the '^' or '0'
+    del_char(false);              // delete the '^' or '0'
     // In Replace mode, restore the characters that '^' or '0' replaced.
     if (State & REPLACE_FLAG) {
       replace_pop_ins();
@@ -3667,7 +3664,7 @@ static void ins_bs_one(colnr_T *vcolp)
       replace_do_bs(-1);
     }
   } else {
-    (void)del_char(false);
+    del_char(false);
   }
 }
 
@@ -3708,7 +3705,7 @@ static bool ins_bs(int c, int mode, int *inserted_space_p)
   if (stop_arrow() == FAIL) {
     return false;
   }
-  int in_indent = inindent(0);
+  bool in_indent = inindent(0);
   if (in_indent) {
     can_cindent = false;
   }
@@ -3766,9 +3763,7 @@ static bool ins_bs(int c, int mode, int *inserted_space_p)
         if (has_format_option(FO_AUTO)
             && has_format_option(FO_WHITE_PAR)) {
           char *ptr = ml_get_buf_mut(curbuf, curwin->w_cursor.lnum);
-          int len;
-
-          len = (int)strlen(ptr);
+          int len = (int)strlen(ptr);
           if (len > 0 && ptr[len - 1] == ' ') {
             ptr[len - 1] = NUL;
           }
@@ -3918,7 +3913,7 @@ static bool ins_bs(int c, int mode, int *inserted_space_p)
             char *p0 = get_cursor_pos_ptr();
             has_composing = utf_composinglike(p0, p0 + utf_ptr2len(p0));
           }
-          (void)del_char(false);
+          del_char(false);
           // If there are combining characters and 'delcombine' is set
           // move the cursor back.  Don't back up before the base character.
           if (has_composing) {
@@ -4062,7 +4057,7 @@ static void ins_s_left(void)
     if (!end_change) {
       AppendCharToRedobuff(K_S_LEFT);
     }
-    (void)bck_word(1, false, false);
+    bck_word(1, false, false);
     curwin->w_set_curswant = true;
   } else {
     vim_beep(BO_CRSR);
@@ -4121,7 +4116,7 @@ static void ins_s_right(void)
     if (!end_change) {
       AppendCharToRedobuff(K_S_RIGHT);
     }
-    (void)fwd_word(1, false, 0);
+    fwd_word(1, false, 0);
     curwin->w_set_curswant = true;
   } else {
     vim_beep(BO_CRSR);
@@ -4234,7 +4229,7 @@ static bool ins_tab(void)
     return false;
   }
 
-  int ind = inindent(0);
+  bool ind = inindent(0);
   if (ind) {
     can_cindent = false;
   }
@@ -4657,7 +4652,7 @@ static void ins_try_si(int c)
       if (State & VREPLACE_FLAG) {
         change_indent(INDENT_SET, i, false, NUL, true);
       } else {
-        (void)set_indent(i, SIN_CHANGED);
+        set_indent(i, SIN_CHANGED);
       }
     } else if (curwin->w_cursor.col > 0) {
       // when inserting '{' after "O" reduce indent, but not
@@ -4689,7 +4684,7 @@ static void ins_try_si(int c)
   if (curwin->w_cursor.col > 0 && can_si && c == '#' && inindent(0)) {
     // remember current indent for next line
     old_indent = get_indent();
-    (void)set_indent(0, SIN_CHANGED);
+    set_indent(0, SIN_CHANGED);
   }
 
   // Adjust ai_col, the char at this position can be deleted.
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 540c10e494..5069f00df0 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -529,7 +529,7 @@ void eval_clear(void)
   free_autoload_scriptnames();
 
   // unreferenced lists and dicts
-  (void)garbage_collect(false);
+  garbage_collect(false);
 
   // functions not garbage collected
   free_all_functions();
@@ -761,7 +761,7 @@ void fill_evalarg_from_eap(evalarg_T *evalarg, exarg_T *eap, bool skip)
 /// @param skip  only parse, don't execute
 ///
 /// @return  true or false.
-bool eval_to_bool(char *arg, bool *error, exarg_T *eap, int skip)
+bool eval_to_bool(char *arg, bool *error, exarg_T *eap, bool skip)
 {
   typval_T tv;
   bool retval = false;
@@ -1726,7 +1726,7 @@ void clear_lval(lval_T *lp)
 /// @param endp  points to just after the parsed name.
 /// @param op    NULL, "+" for "+=", "-" for "-=", "*" for "*=", "/" for "/=",
 ///              "%" for "%=", "." for ".=" or "=" for "=".
-void set_var_lval(lval_T *lp, char *endp, typval_T *rettv, int copy, const bool is_const,
+void set_var_lval(lval_T *lp, char *endp, typval_T *rettv, bool copy, const bool is_const,
                   const char *op)
 {
   int cc;
@@ -1795,8 +1795,8 @@ void set_var_lval(lval_T *lp, char *endp, typval_T *rettv, int copy, const bool
       return;
     }
 
-    (void)tv_list_assign_range(lp->ll_list, rettv->vval.v_list,
-                               lp->ll_n1, lp->ll_n2, lp->ll_empty2, op, lp->ll_name);
+    tv_list_assign_range(lp->ll_list, rettv->vval.v_list,
+                         lp->ll_n1, lp->ll_n2, lp->ll_empty2, op, lp->ll_name);
   } else {
     typval_T oldtv = TV_INITIAL_VALUE;
     dict_T *dict = lp->ll_dict;
@@ -8585,9 +8585,9 @@ char *do_string_sub(char *str, char *pat, char *sub, typval_T *expr, const char
       int i = (int)(regmatch.startp[0] - tail);
       memmove((char *)ga.ga_data + ga.ga_len, tail, (size_t)i);
       // add the substituted text
-      (void)vim_regsub(&regmatch, sub, expr,
-                       (char *)ga.ga_data + ga.ga_len + i, sublen,
-                       REGSUB_COPY | REGSUB_MAGIC);
+      vim_regsub(&regmatch, sub, expr,
+                 (char *)ga.ga_data + ga.ga_len + i, sublen,
+                 REGSUB_COPY | REGSUB_MAGIC);
       ga.ga_len += i + sublen - 1;
       tail = regmatch.endp[0];
       if (*tail == NUL) {
@@ -8727,7 +8727,7 @@ typval_T eval_call_provider(char *provider, char *method, list_T *arguments, boo
   funcexe.fe_firstline = curwin->w_cursor.lnum;
   funcexe.fe_lastline = curwin->w_cursor.lnum;
   funcexe.fe_evaluate = true;
-  (void)call_func(func, name_len, &rettv, 2, argvars, &funcexe);
+  call_func(func, name_len, &rettv, 2, argvars, &funcexe);
 
   tv_list_unref(arguments);
   // Restore caller scope information
diff --git a/src/nvim/eval/buffer.c b/src/nvim/eval/buffer.c
index 1f3b92804d..2ae2b94ce9 100644
--- a/src/nvim/eval/buffer.c
+++ b/src/nvim/eval/buffer.c
@@ -583,7 +583,8 @@ void f_getbufinfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 ///
 /// @return  range (from start to end) of lines in rettv from the specified
 ///          buffer.
-static void get_buffer_lines(buf_T *buf, linenr_T start, linenr_T end, int retlist, typval_T *rettv)
+static void get_buffer_lines(buf_T *buf, linenr_T start, linenr_T end, bool retlist,
+                             typval_T *rettv)
 {
   rettv->v_type = (retlist ? VAR_LIST : VAR_STRING);
   rettv->vval.v_string = NULL;
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 30a86b1917..6fae90134a 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -1668,7 +1668,7 @@ static void f_exepath(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
   char *path = NULL;
 
-  (void)os_can_exe(tv_get_string(&argvars[0]), &path, true);
+  os_can_exe(tv_get_string(&argvars[0]), &path, true);
 
 #ifdef BACKSLASH_IN_FILENAME
   if (path != NULL) {
@@ -2214,8 +2214,8 @@ static void f_fnamemodify(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     len = strlen(fname);
     if (*mods != NUL) {
       size_t usedlen = 0;
-      (void)modify_fname((char *)mods, false, &usedlen,
-                         (char **)&fname, &fbuf, &len);
+      modify_fname((char *)mods, false, &usedlen,
+                   (char **)&fname, &fbuf, &len);
     }
   }
 
@@ -3634,7 +3634,7 @@ static void f_inputlist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   });
 
   // Ask for choice.
-  int mouse_used;
+  bool mouse_used;
   int selected = prompt_for_number(&mouse_used);
   if (mouse_used) {
     selected -= lines_left;
@@ -4163,7 +4163,7 @@ static void f_jobstop(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   const char *error = NULL;
   if (data->is_rpc) {
     // Ignore return code, but show error later.
-    (void)channel_close(data->id, kChannelPartRpc, &error);
+    channel_close(data->id, kChannelPartRpc, &error);
   }
   process_stop(&data->stream.proc);
   rettv->vval.v_number = 1;
@@ -5211,7 +5211,7 @@ static void f_printf(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     if (!did_emsg) {
       char *s = xmalloc((size_t)len + 1);
       rettv->vval.v_string = s;
-      (void)vim_vsnprintf_typval(s, (size_t)len + 1, fmt, dummy_ap, argvars + 1);
+      vim_vsnprintf_typval(s, (size_t)len + 1, fmt, dummy_ap, argvars + 1);
     }
     did_emsg |= saved_did_emsg;
   }
@@ -5802,7 +5802,7 @@ static void f_getreginfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   if (list == NULL) {
     return;
   }
-  (void)tv_dict_add_list(dict, S_LEN("regcontents"), list);
+  tv_dict_add_list(dict, S_LEN("regcontents"), list);
 
   char buf[NUMBUFLEN + 2];
   buf[0] = NUL;
@@ -5821,15 +5821,15 @@ static void f_getreginfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   case kMTUnknown:
     abort();
   }
-  (void)tv_dict_add_str(dict, S_LEN("regtype"), buf);
+  tv_dict_add_str(dict, S_LEN("regtype"), buf);
 
   buf[0] = (char)get_register_name(get_unname_register());
   buf[1] = NUL;
   if (regname == '"') {
-    (void)tv_dict_add_str(dict, S_LEN("points_to"), buf);
+    tv_dict_add_str(dict, S_LEN("points_to"), buf);
   } else {
-    (void)tv_dict_add_bool(dict, S_LEN("isunnamed"),
-                           regname == buf[0] ? kBoolVarTrue : kBoolVarFalse);
+    tv_dict_add_bool(dict, S_LEN("isunnamed"),
+                     regname == buf[0] ? kBoolVarTrue : kBoolVarFalse);
   }
 }
 
@@ -8082,7 +8082,7 @@ static void f_str2float(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   if (*p == '+' || *p == '-') {
     p = skipwhite(p + 1);
   }
-  (void)string2float(p, &rettv->vval.v_float);
+  string2float(p, &rettv->vval.v_float);
   if (isneg) {
     rettv->vval.v_float *= -1;
   }
@@ -8397,7 +8397,7 @@ static void f_synconcealed(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
 
   if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count && col >= 0
       && (size_t)col <= strlen(ml_get(lnum)) && curwin->w_p_cole > 0) {
-    (void)syn_get_id(curwin, lnum, col, false, NULL, false);
+    syn_get_id(curwin, lnum, col, false, NULL, false);
     syntax_flags = get_syntax_info(&matchid);
 
     // get the conceal character
@@ -8435,7 +8435,7 @@ static void f_synstack(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       && col >= 0
       && (size_t)col <= strlen(ml_get(lnum))) {
     tv_list_alloc_ret(rettv, kListLenMayKnow);
-    (void)syn_get_id(curwin, lnum, col, false, NULL, true);
+    syn_get_id(curwin, lnum, col, false, NULL, true);
 
     int id;
     int i = 0;
@@ -8509,8 +8509,8 @@ static void f_taglist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   if (argvars[1].v_type != VAR_UNKNOWN) {
     fname = tv_get_string(&argvars[1]);
   }
-  (void)get_tags(tv_list_alloc_ret(rettv, kListLenUnknown),
-                 (char *)tag_pattern, (char *)fname);
+  get_tags(tv_list_alloc_ret(rettv, kListLenUnknown),
+           (char *)tag_pattern, (char *)fname);
 }
 
 /// "tempname()" function
@@ -8629,7 +8629,7 @@ static void f_termopen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   curbuf->b_p_swf = false;
 
   apply_autocmds(EVENT_BUFFILEPRE, NULL, NULL, false, curbuf);
-  (void)setfname(curbuf, NameBuff, NULL, true);
+  setfname(curbuf, NameBuff, NULL, true);
   apply_autocmds(EVENT_BUFFILEPOST, NULL, NULL, false, curbuf);
 
   // Save the job id and pid in b:terminal_job_{id,pid}
diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index 42b105b2a2..18168d77b7 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -2909,7 +2909,7 @@ static int tv_blob_index(const blob_T *blob, int len, varnumber_T idx, typval_T
   return OK;
 }
 
-int tv_blob_slice_or_index(const blob_T *blob, int is_range, varnumber_T n1, varnumber_T n2,
+int tv_blob_slice_or_index(const blob_T *blob, bool is_range, varnumber_T n1, varnumber_T n2,
                            bool exclusive, typval_T *rettv)
 {
   int len = tv_blob_len(rettv->vval.v_blob);
diff --git a/src/nvim/eval/userfunc.c b/src/nvim/eval/userfunc.c
index 5d8c173dd1..e74bf39476 100644
--- a/src/nvim/eval/userfunc.c
+++ b/src/nvim/eval/userfunc.c
@@ -1175,7 +1175,7 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
     // A Lambda always has the command "return {expr}".  It is much faster
     // to evaluate {expr} directly.
     ex_nesting_level++;
-    (void)eval1(&p, rettv, &EVALARG_EVALUATE);
+    eval1(&p, rettv, &EVALARG_EVALUATE);
     ex_nesting_level--;
   } else {
     // call do_cmdline() to execute the lines
@@ -2069,7 +2069,7 @@ char *save_function_name(char **name, bool skip, int flags, funcdict_T *fudi)
 
   if (strncmp(p, "<lambda>", 8) == 0) {
     p += 8;
-    (void)getdigits(&p, false, 0);
+    getdigits(&p, false, 0);
     saved = xmemdupz(*name, (size_t)(p - *name));
     if (fudi != NULL) {
       CLEAR_POINTER(fudi);
@@ -3658,7 +3658,7 @@ bool free_unref_funccal(int copyID, int testing)
   if (did_free_funccal) {
     // When a funccal was freed some more items might be garbage
     // collected, so run again.
-    (void)garbage_collect(testing);
+    garbage_collect(testing);
   }
   return did_free;
 }
diff --git a/src/nvim/eval/vars.c b/src/nvim/eval/vars.c
index dd984e8819..d57874480d 100644
--- a/src/nvim/eval/vars.c
+++ b/src/nvim/eval/vars.c
@@ -378,7 +378,7 @@ void ex_let(exarg_T *eap)
       if (!eap->skip) {
         op[0] = '=';
         op[1] = NUL;
-        (void)ex_let_vars(eap->arg, &rettv, false, semicolon, var_count, is_const, op);
+        ex_let_vars(eap->arg, &rettv, false, semicolon, var_count, is_const, op);
       }
       tv_clear(&rettv);
     }
@@ -415,7 +415,7 @@ void ex_let(exarg_T *eap)
   clear_evalarg(&evalarg, eap);
 
   if (!eap->skip && eval_res != FAIL) {
-    (void)ex_let_vars(eap->arg, &rettv, false, semicolon, var_count, is_const, op);
+    ex_let_vars(eap->arg, &rettv, false, semicolon, var_count, is_const, op);
   }
   if (eval_res != FAIL) {
     tv_clear(&rettv);
@@ -1303,7 +1303,7 @@ void vars_clear(hashtab_T *ht)
 }
 
 /// Like vars_clear(), but only free the value if "free_val" is true.
-void vars_clear_ext(hashtab_T *ht, int free_val)
+void vars_clear_ext(hashtab_T *ht, bool free_val)
 {
   int todo;
   hashitem_T *hi;
diff --git a/src/nvim/eval/window.c b/src/nvim/eval/window.c
index 230aec6abc..cb9e9293ae 100644
--- a/src/nvim/eval/window.c
+++ b/src/nvim/eval/window.c
@@ -675,13 +675,13 @@ static void win_move_into_split(win_T *wp, win_T *targetwin, int size, int flags
 
   // Remove the old window and frame from the tree of frames
   int dir;
-  (void)winframe_remove(wp, &dir, NULL);
+  winframe_remove(wp, &dir, NULL);
   win_remove(wp, NULL);
   last_status(false);     // may need to remove last status line
-  (void)win_comp_pos();   // recompute window positions
+  win_comp_pos();   // recompute window positions
 
   // Split a window on the desired side and put the old window there
-  (void)win_split_ins(size, flags, wp, dir);
+  win_split_ins(size, flags, wp, dir);
 
   // If splitting horizontally, try to preserve height
   if (size == 0 && !(flags & WSP_VERT)) {
diff --git a/src/nvim/event/multiqueue.c b/src/nvim/event/multiqueue.c
index fd6f88153b..f1b4414cb5 100644
--- a/src/nvim/event/multiqueue.c
+++ b/src/nvim/event/multiqueue.c
@@ -156,7 +156,7 @@ void multiqueue_purge_events(MultiQueue *self)
 {
   assert(self);
   while (!multiqueue_empty(self)) {
-    (void)multiqueue_remove(self);
+    multiqueue_remove(self);
   }
 }
 
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index 9abe347e94..4d86b4d478 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -283,12 +283,12 @@ void ex_align(exarg_T *eap)
         // to the right.
         if (has_tab) {
           while (new_indent > 0) {
-            (void)set_indent(new_indent, 0);
+            set_indent(new_indent, 0);
             if (linelen(NULL) <= width) {
               // Now try to move the line as much as possible to
               // the right.  Stop when it moves too far.
               do {
-                (void)set_indent(++new_indent, 0);
+                set_indent(++new_indent, 0);
               } while (linelen(NULL) <= width);
               new_indent--;
               break;
@@ -301,7 +301,7 @@ void ex_align(exarg_T *eap)
     if (new_indent < 0) {
       new_indent = 0;
     }
-    (void)set_indent(new_indent, 0);                    // set indent
+    set_indent(new_indent, 0);                    // set indent
   }
   changed_lines(curbuf, eap->line1, 0, eap->line2 + 1, 0, true);
   curwin->w_cursor = save_curpos;
@@ -341,13 +341,13 @@ static int linelen(int *has_tab)
 static char *sortbuf1;
 static char *sortbuf2;
 
-static int sort_lc;       ///< sort using locale
-static int sort_ic;       ///< ignore case
-static int sort_nr;       ///< sort on number
-static int sort_rx;       ///< sort on regex instead of skipping it
-static int sort_flt;      ///< sort on floating number
+static bool sort_lc;      ///< sort using locale
+static bool sort_ic;      ///< ignore case
+static bool sort_nr;      ///< sort on number
+static bool sort_rx;      ///< sort on regex instead of skipping it
+static bool sort_flt;     ///< sort on floating number
 
-static int sort_abort;    ///< flag to indicate if sorting has been interrupted
+static bool sort_abort;   ///< flag to indicate if sorting has been interrupted
 
 /// Struct to store info to be sorted.
 typedef struct {
@@ -450,7 +450,7 @@ void ex_sort(exarg_T *eap)
   regmatch.regprog = NULL;
   sorti_T *nrs = xmalloc(count * sizeof(sorti_T));
 
-  sort_abort = sort_ic = sort_lc = sort_rx = sort_nr = sort_flt = 0;
+  sort_abort = sort_ic = sort_lc = sort_rx = sort_nr = sort_flt = false;
   size_t format_found = 0;
   bool change_occurred = false;   // Buffer contents changed.
 
@@ -464,10 +464,10 @@ void ex_sort(exarg_T *eap)
     } else if (*p == 'r') {
       sort_rx = true;
     } else if (*p == 'n') {
-      sort_nr = 1;
+      sort_nr = true;
       format_found++;
     } else if (*p == 'f') {
-      sort_flt = 1;
+      sort_flt = true;
       format_found++;
     } else if (*p == 'b') {
       sort_what = STR2NR_BIN + STR2NR_FORCE;
@@ -521,7 +521,7 @@ void ex_sort(exarg_T *eap)
 
   // From here on "sort_nr" is used as a flag for any integer number
   // sorting.
-  sort_nr += sort_what;
+  sort_nr |= sort_what;
 
   // Make an array with all line numbers.  This avoids having to copy all
   // the lines into allocated memory.
@@ -1305,7 +1305,7 @@ void do_shell(char *cmd, int flags)
   // This ui_cursor_goto is required for when the '\n' resulted in a "delete line
   // 1" command to the terminal.
   ui_cursor_goto(msg_row, msg_col);
-  (void)call_shell(cmd, (ShellOpts)flags, NULL);
+  call_shell(cmd, (ShellOpts)flags, NULL);
   if (msg_silent == 0) {
     msg_didout = true;
   }
@@ -1462,7 +1462,7 @@ void append_redir(char *const buf, const size_t buflen, const char *const opt,
   }
 }
 
-void print_line_no_prefix(linenr_T lnum, int use_number, int list)
+void print_line_no_prefix(linenr_T lnum, int use_number, bool list)
 {
   char numbuf[30];
 
@@ -1475,9 +1475,9 @@ void print_line_no_prefix(linenr_T lnum, int use_number, int list)
 }
 
 /// Print a text line.  Also in silent mode ("ex -s").
-void print_line(linenr_T lnum, int use_number, int list)
+void print_line(linenr_T lnum, int use_number, bool list)
 {
-  int save_silent = silent_mode;
+  bool save_silent = silent_mode;
 
   // apply :filter /pat/
   if (message_filtered(ml_get(lnum))) {
@@ -1566,7 +1566,7 @@ void ex_file(exarg_T *eap)
 void ex_update(exarg_T *eap)
 {
   if (curbufIsChanged()) {
-    (void)do_write(eap);
+    do_write(eap);
   }
 }
 
@@ -1582,7 +1582,7 @@ void ex_write(exarg_T *eap)
   if (eap->usefilter) {  // input lines to shell command
     do_bang(1, eap, false, true, false);
   } else {
-    (void)do_write(eap);
+    do_write(eap);
   }
 }
 
@@ -1605,7 +1605,7 @@ static int check_writable(const char *fname)
 /// @return  FAIL for failure, OK otherwise.
 int do_write(exarg_T *eap)
 {
-  int other;
+  bool other;
   char *fname = NULL;            // init to shut up gcc
   int retval = FAIL;
   char *free_fname = NULL;
@@ -1724,7 +1724,7 @@ int do_write(exarg_T *eap)
       // If 'filetype' was empty try detecting it now.
       if (*curbuf->b_p_ft == NUL) {
         if (augroup_exists("filetypedetect")) {
-          (void)do_doautocmd("filetypedetect BufRead", true, NULL);
+          do_doautocmd("filetypedetect BufRead", true, NULL);
         }
         do_modelines(0);
       }
@@ -1774,7 +1774,7 @@ theend:
 /// @param other   writing under other name
 ///
 /// @return  OK if it's OK, FAIL if it is not.
-int check_overwrite(exarg_T *eap, buf_T *buf, char *fname, char *ffname, int other)
+int check_overwrite(exarg_T *eap, buf_T *buf, char *fname, char *ffname, bool other)
 {
   // Write to another file or b_flags set or not writing the whole file:
   // overwriting only allowed with '!'
@@ -1815,8 +1815,6 @@ int check_overwrite(exarg_T *eap, buf_T *buf, char *fname, char *ffname, int oth
     // For ":w! filename" check that no swap file exists for "filename".
     if (other && !emsg_silent) {
       char *dir;
-      char *p;
-      char *swapname;
 
       // We only try the first entry in 'directory', without checking if
       // it's writable.  If the "." directory is not writable the write
@@ -1828,10 +1826,10 @@ int check_overwrite(exarg_T *eap, buf_T *buf, char *fname, char *ffname, int oth
         STRCPY(dir, ".");
       } else {
         dir = xmalloc(MAXPATHL);
-        p = p_dir;
+        char *p = p_dir;
         copy_option_part(&p, dir, MAXPATHL, ",");
       }
-      swapname = makeswapname(fname, ffname, curbuf, dir);
+      char *swapname = makeswapname(fname, ffname, curbuf, dir);
       xfree(dir);
       if (os_path_exists(swapname)) {
         if (p_confirm || (cmdmod.cmod_flags & CMOD_CONFIRM)) {
@@ -1998,11 +1996,11 @@ static int check_readonly(int *forceit, buf_T *buf)
 ///           GETFILE_NOT_WRITTEN for "not written" error,
 ///           GETFILE_SAME_FILE for success
 ///           GETFILE_OPEN_OTHER for successfully opening another file.
-int getfile(int fnum, char *ffname_arg, char *sfname_arg, int setpm, linenr_T lnum, int forceit)
+int getfile(int fnum, char *ffname_arg, char *sfname_arg, bool setpm, linenr_T lnum, bool forceit)
 {
   char *ffname = ffname_arg;
   char *sfname = sfname_arg;
-  int other;
+  bool other;
   int retval;
   char *free_me = NULL;
 
@@ -2179,7 +2177,7 @@ int do_ecmd(int fnum, char *ffname, char *sfname, exarg_T *eap, linenr_T newlnum
                        | ((flags & ECMD_FORCEIT) ? CCGD_FORCEIT : 0)
                        | (eap == NULL ? 0 : CCGD_EXCMD))) {
     if (fnum == 0 && other_file && ffname != NULL) {
-      (void)setaltfname(ffname, sfname, newlnum < 0 ? 0 : newlnum);
+      setaltfname(ffname, sfname, newlnum < 0 ? 0 : newlnum);
     }
     goto theend;
   }
@@ -2270,7 +2268,7 @@ int do_ecmd(int fnum, char *ffname, char *sfname, exarg_T *eap, linenr_T newlnum
       // Existing memfile.
       oldbuf = true;
       set_bufref(&bufref, buf);
-      (void)buf_check_timestamp(buf);
+      buf_check_timestamp(buf);
       // Check if autocommands made buffer invalid or changed the current
       // buffer.
       if (!bufref_valid(&bufref) || curbuf != old_curbuf.br_buf) {
@@ -2606,7 +2604,7 @@ int do_ecmd(int fnum, char *ffname, char *sfname, exarg_T *eap, linenr_T newlnum
   // If the window options were changed may need to set the spell language.
   // Can only do this after the buffer has been properly setup.
   if (did_get_winopts && curwin->w_p_spell && *curwin->w_s->b_p_spl != NUL) {
-    (void)parse_spelllang(curwin);
+    parse_spelllang(curwin);
   }
 
   if (command == NULL) {
@@ -2669,7 +2667,7 @@ int do_ecmd(int fnum, char *ffname, char *sfname, exarg_T *eap, linenr_T newlnum
   }
 
   if (curbuf->b_kmap_state & KEYMAP_INIT) {
-    (void)keymap_init();
+    keymap_init();
   }
 
   RedrawingDisabled--;
@@ -2722,7 +2720,7 @@ void ex_append(exarg_T *eap)
   linenr_T lnum = eap->line2;
   int indent = 0;
   char *p;
-  int empty = (curbuf->b_ml.ml_flags & ML_EMPTY);
+  bool empty = (curbuf->b_ml.ml_flags & ML_EMPTY);
 
   // the ! flag toggles autoindent
   if (eap->forceit) {
@@ -2824,7 +2822,7 @@ void ex_append(exarg_T *eap)
 
     if (empty) {
       ml_delete(2, false);
-      empty = 0;
+      empty = false;
     }
   }
   State = MODE_NORMAL;
@@ -3954,11 +3952,11 @@ static int do_sub(exarg_T *eap, const proftime_T timeout, const int cmdpreview_n
           current_match.start.col = start_col;
 
           textlock++;
-          (void)vim_regsub_multi(&regmatch,
-                                 sub_firstlnum - regmatch.startpos[0].lnum,
-                                 sub, new_end, sublen,
-                                 REGSUB_COPY | REGSUB_BACKSLASH
-                                 | (magic_isset() ? REGSUB_MAGIC : 0));
+          vim_regsub_multi(&regmatch,
+                           sub_firstlnum - regmatch.startpos[0].lnum,
+                           sub, new_end, sublen,
+                           REGSUB_COPY | REGSUB_BACKSLASH
+                           | (magic_isset() ? REGSUB_MAGIC : 0));
           textlock--;
           sub_nsubs++;
           did_sub = true;
@@ -4677,7 +4675,7 @@ static int show_sub(exarg_T *eap, pos_T old_cusr, PreviewLines *preview_lines, i
 /// :substitute command.
 void ex_substitute(exarg_T *eap)
 {
-  (void)do_sub(eap, profile_zero(), 0, 0);
+  do_sub(eap, profile_zero(), 0, 0);
 }
 
 /// :substitute command preview callback.
diff --git a/src/nvim/ex_cmds2.c b/src/nvim/ex_cmds2.c
index 975335ba20..504078bcf6 100644
--- a/src/nvim/ex_cmds2.c
+++ b/src/nvim/ex_cmds2.c
@@ -100,7 +100,7 @@ void ex_perldo(exarg_T *eap)
 /// Careful: autocommands may make "buf" invalid!
 ///
 /// @return FAIL for failure, OK otherwise
-int autowrite(buf_T *buf, int forceit)
+int autowrite(buf_T *buf, bool forceit)
 {
   bufref_T bufref;
 
@@ -132,7 +132,7 @@ void autowrite_all(void)
     if (bufIsChanged(buf) && !buf->b_p_ro && !bt_dontwrite(buf)) {
       bufref_T bufref;
       set_bufref(&bufref, buf);
-      (void)buf_write_all(buf, false);
+      buf_write_all(buf, false);
       // an autocommand may have deleted the buffer
       if (!bufref_valid(&bufref)) {
         buf = firstbuf;
@@ -145,7 +145,7 @@ void autowrite_all(void)
 /// For flags use the CCGD_ values.
 bool check_changed(buf_T *buf, int flags)
 {
-  int forceit = (flags & CCGD_FORCEIT);
+  bool forceit = (flags & CCGD_FORCEIT);
   bufref_T bufref;
   set_bufref(&bufref, buf);
 
@@ -211,7 +211,7 @@ void dialog_changed(buf_T *buf, bool checkall)
     if (buf->b_fname != NULL
         && check_overwrite(&ea, buf, buf->b_fname, buf->b_ffname, false) == OK) {
       // didn't hit Cancel
-      (void)buf_write_all(buf, false);
+      buf_write_all(buf, false);
     }
   } else if (ret == VIM_NO) {
     unchanged(buf, true, false);
@@ -227,7 +227,7 @@ void dialog_changed(buf_T *buf, bool checkall)
         if (buf2->b_fname != NULL
             && check_overwrite(&ea, buf2, buf2->b_fname, buf2->b_ffname, false) == OK) {
           // didn't hit Cancel
-          (void)buf_write_all(buf2, false);
+          buf_write_all(buf2, false);
         }
         // an autocommand may have deleted the buffer
         if (!bufref_valid(&bufref)) {
@@ -261,7 +261,7 @@ bool dialog_close_terminal(buf_T *buf)
 
 /// @return true if the buffer "buf" can be abandoned, either by making it
 /// hidden, autowriting it or unloading it.
-bool can_abandon(buf_T *buf, int forceit)
+bool can_abandon(buf_T *buf, bool forceit)
 {
   return buf_hide(buf)
          || !bufIsChanged(buf)
@@ -423,7 +423,7 @@ int check_fname(void)
 /// Flush the contents of a buffer, unless it has no file name.
 ///
 /// @return  FAIL for failure, OK otherwise
-int buf_write_all(buf_T *buf, int forceit)
+int buf_write_all(buf_T *buf, bool forceit)
 {
   buf_T *old_curbuf = curbuf;
 
@@ -744,7 +744,7 @@ void ex_checktime(exarg_T *eap)
   } else {
     buf_T *buf = buflist_findnr((int)eap->line2);
     if (buf != NULL) {           // cannot happen?
-      (void)buf_check_timestamp(buf);
+      buf_check_timestamp(buf);
     }
   }
   no_check_timestamps = save_no_check_timestamps;
@@ -763,7 +763,7 @@ static void script_host_execute(char *name, exarg_T *eap)
     tv_list_append_number(args, (int)eap->line1);
     tv_list_append_number(args, (int)eap->line2);
 
-    (void)eval_call_provider(name, "execute", args, true);
+    eval_call_provider(name, "execute", args, true);
   }
 }
 
@@ -779,7 +779,7 @@ static void script_host_execute_file(char *name, exarg_T *eap)
     // current range
     tv_list_append_number(args, (int)eap->line1);
     tv_list_append_number(args, (int)eap->line2);
-    (void)eval_call_provider(name, "execute_file", args, true);
+    eval_call_provider(name, "execute_file", args, true);
   }
 }
 
@@ -790,7 +790,7 @@ static void script_host_do_range(char *name, exarg_T *eap)
     tv_list_append_number(args, (int)eap->line1);
     tv_list_append_number(args, (int)eap->line2);
     tv_list_append_string(args, eap->arg, -1);
-    (void)eval_call_provider(name, "do_range", args, true);
+    eval_call_provider(name, "do_range", args, true);
   }
 }
 
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index 964ddca887..0b6efdaab6 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -190,8 +190,8 @@ static void restore_dbg_stuff(struct dbg_stuff *dsp)
   trylevel = dsp->trylevel;
   force_abort = dsp->force_abort;
   caught_stack = dsp->caught_stack;
-  (void)v_exception(dsp->vv_exception);
-  (void)v_throwpoint(dsp->vv_throwpoint);
+  v_exception(dsp->vv_exception);
+  v_throwpoint(dsp->vv_throwpoint);
   did_emsg = dsp->did_emsg;
   got_int = dsp->got_int;
   did_throw = dsp->did_throw;
@@ -710,7 +710,7 @@ int do_cmdline(char *cmdline, LineGetter fgetline, void *cookie, int flags)
     }
 
     // Convert an interrupt to an exception if appropriate.
-    (void)do_intthrow(&cstack);
+    do_intthrow(&cstack);
 
     // Continue executing command lines when:
     // - no CTRL-C typed, no aborting error, no exception thrown or try
@@ -1703,8 +1703,8 @@ int execute_cmd(exarg_T *eap, CmdParseInfo *cmdinfo, bool preview)
       && eap->addr_type == ADDR_LINES) {
     // Put the first line at the start of a closed fold, put the last line
     // at the end of a closed fold.
-    (void)hasFolding(eap->line1, &eap->line1, NULL);
-    (void)hasFolding(eap->line2, NULL, &eap->line2);
+    hasFolding(eap->line1, &eap->line1, NULL);
+    hasFolding(eap->line2, NULL, &eap->line2);
   }
 
   // Use first argument as count when possible
@@ -1958,7 +1958,7 @@ static char *do_one_cmd(char **cmdlinep, int flags, cstack_T *cstack, LineGetter
   }
   if (!ea.skip && got_int) {
     ea.skip = true;
-    (void)do_intthrow(cstack);
+    do_intthrow(cstack);
   }
 
   // 4. Parse a range specifier of the form: addr [,addr] [;addr] ..
@@ -2170,8 +2170,8 @@ static char *do_one_cmd(char **cmdlinep, int flags, cstack_T *cstack, LineGetter
       && ea.addr_type == ADDR_LINES) {
     // Put the first line at the start of a closed fold, put the last line
     // at the end of a closed fold.
-    (void)hasFolding(ea.line1, &ea.line1, NULL);
-    (void)hasFolding(ea.line2, NULL, &ea.line2);
+    hasFolding(ea.line1, &ea.line1, NULL);
+    hasFolding(ea.line2, NULL, &ea.line2);
   }
 
   // For the ":make" and ":grep" commands we insert the 'makeprg'/'grepprg'
@@ -3259,7 +3259,7 @@ static const char *addr_error(cmd_addr_T addr_type)
 /// @param errormsg       Error message, if any
 ///
 /// @return               MAXLNUM when no Ex address was found.
-static linenr_T get_address(exarg_T *eap, char **ptr, cmd_addr_T addr_type, int skip, bool silent,
+static linenr_T get_address(exarg_T *eap, char **ptr, cmd_addr_T addr_type, bool skip, bool silent,
                             int to_other_file, int address_count, const char **errormsg)
   FUNC_ATTR_NONNULL_ALL
 {
@@ -3379,7 +3379,7 @@ static linenr_T get_address(exarg_T *eap, char **ptr, cmd_addr_T addr_type, int
         fmark_T *fm = mark_get(curbuf, curwin, NULL, flag, *cmd);
         cmd++;
         if (fm != NULL && fm->fnum != curbuf->handle) {
-          (void)mark_move_to(fm, 0);
+          mark_move_to(fm, 0);
           // Jumped to another file.
           lnum = curwin->w_cursor.lnum;
         } else {
@@ -3553,7 +3553,7 @@ static linenr_T get_address(exarg_T *eap, char **ptr, cmd_addr_T addr_type, int
         // closed fold after the first address.
         if (addr_type == ADDR_LINES && (i == '-' || i == '+')
             && address_count >= 2) {
-          (void)hasFolding(lnum, NULL, &lnum);
+          hasFolding(lnum, NULL, &lnum);
         }
         if (i == '-') {
           lnum -= n;
@@ -3780,12 +3780,12 @@ int expand_filename(exarg_T *eap, char **cmdlinep, const char **errormsgp)
   // Decide to expand wildcards *before* replacing '%', '#', etc.  If
   // the file name contains a wildcard it should not cause expanding.
   // (it will be expanded anyway if there is a wildcard before replacing).
-  int has_wildcards = path_has_wildcard(p);
+  bool has_wildcards = path_has_wildcard(p);
   while (*p != NUL) {
     // Skip over `=expr`, wildcards in it are not expanded.
     if (p[0] == '`' && p[1] == '=') {
       p += 2;
-      (void)skip_expr(&p, NULL);
+      skip_expr(&p, NULL);
       if (*p == '`') {
         p++;
       }
@@ -3860,9 +3860,7 @@ int expand_filename(exarg_T *eap, char **cmdlinep, const char **errormsgp)
          || eap->cmdidx == CMD_bang
          || eap->cmdidx == CMD_terminal)
         && strpbrk(repl, "!") != NULL) {
-      char *l;
-
-      l = vim_strsave_escaped(repl, "!");
+      char *l = vim_strsave_escaped(repl, "!");
       xfree(repl);
       repl = l;
     }
@@ -3890,7 +3888,7 @@ int expand_filename(exarg_T *eap, char **cmdlinep, const char **errormsgp)
         p = NULL;
       }
       if (p != NULL) {
-        (void)repl_cmdline(eap, eap->arg, strlen(eap->arg), p, cmdlinep);
+        repl_cmdline(eap, eap->arg, strlen(eap->arg), p, cmdlinep);
       }
     }
 
@@ -3918,7 +3916,7 @@ int expand_filename(exarg_T *eap, char **cmdlinep, const char **errormsgp)
       if (p == NULL) {
         return FAIL;
       }
-      (void)repl_cmdline(eap, eap->arg, strlen(eap->arg), p, cmdlinep);
+      repl_cmdline(eap, eap->arg, strlen(eap->arg), p, cmdlinep);
       xfree(p);
     }
   }
@@ -4004,7 +4002,7 @@ void separate_nextcmd(exarg_T *eap)
     } else if (p[0] == '`' && p[1] == '=' && (eap->argt & EX_XFILE)) {
       // Skip over `=expr` when wildcards are expanded.
       p += 2;
-      (void)skip_expr(&p, NULL);
+      skip_expr(&p, NULL);
       if (*p == NUL) {  // stop at NUL after CTRL-V
         break;
       }
@@ -4063,7 +4061,7 @@ static char *getargcmd(char **argp)
 /// Find end of "+command" argument.  Skip over "\ " and "\\".
 ///
 /// @param rembs  true to halve the number of backslashes
-char *skip_cmd_arg(char *p, int rembs)
+char *skip_cmd_arg(char *p, bool rembs)
 {
   while (*p && !ascii_isspace(*p)) {
     if (*p == '\\' && p[1] != NUL) {
@@ -4376,7 +4374,7 @@ static void ex_doautocmd(exarg_T *eap)
   int call_do_modelines = check_nomodeline(&arg);
   bool did_aucmd;
 
-  (void)do_doautocmd(arg, false, &did_aucmd);
+  do_doautocmd(arg, false, &did_aucmd);
   // Only when there is no <nomodeline>.
   if (call_do_modelines && did_aucmd) {
     do_modelines(0);
@@ -4508,7 +4506,7 @@ char *check_nextcmd(char *p)
 /// @param   message  when false check only, no messages
 ///
 /// @return  FAIL and give error message if 'message' true, return OK otherwise
-static int check_more(int message, bool forceit)
+static int check_more(bool message, bool forceit)
 {
   int n = ARGCOUNT - curwin->w_arg_idx - 1;
 
@@ -5371,9 +5369,9 @@ void do_exedit(exarg_T *eap, win_T *old_curwin)
        || eap->cmdidx == CMD_vnew) && *eap->arg == NUL) {
     // ":new" or ":tabnew" without argument: edit a new empty buffer
     setpcmark();
-    (void)do_ecmd(0, NULL, NULL, eap, ECMD_ONE,
-                  ECMD_HIDE + (eap->forceit ? ECMD_FORCEIT : 0),
-                  old_curwin == NULL ? curwin : NULL);
+    do_ecmd(0, NULL, NULL, eap, ECMD_ONE,
+            ECMD_HIDE + (eap->forceit ? ECMD_FORCEIT : 0),
+            old_curwin == NULL ? curwin : NULL);
   } else if ((eap->cmdidx != CMD_split && eap->cmdidx != CMD_vsplit)
              || *eap->arg != NUL) {
     // Can't edit another file when "textlock" or "curbuf->b_ro_locked" is set.
@@ -5555,7 +5553,7 @@ static void ex_read(exarg_T *eap)
                  eap->line2, 0, (linenr_T)MAXLNUM, eap, 0, false);
   } else {
     if (vim_strchr(p_cpo, CPO_ALTREAD) != NULL) {
-      (void)setaltfname(eap->arg, eap->arg, 1);
+      setaltfname(eap->arg, eap->arg, 1);
     }
     i = readfile(eap->arg, NULL,
                  eap->line2, 0, (linenr_T)MAXLNUM, eap, 0, false);
@@ -5826,7 +5824,7 @@ void do_sleep(int64_t msec)
   // If CTRL-C was typed to interrupt the sleep, drop the CTRL-C from the
   // input buffer, otherwise a following call to input() fails.
   if (got_int) {
-    (void)vpeekc();
+    vpeekc();
   }
 }
 
@@ -5911,7 +5909,7 @@ static void ex_operators(exarg_T *eap)
 
   case CMD_yank:
     oa.op_type = OP_YANK;
-    (void)op_yank(&oa, true);
+    op_yank(&oa, true);
     break;
 
   default:          // CMD_rshift or CMD_lshift
@@ -6053,7 +6051,7 @@ static void ex_at(exarg_T *eap)
   // Continue until the stuff buffer is empty and all added characters
   // have been consumed.
   while (!stuff_empty() || typebuf.tb_len > prev_len) {
-    (void)do_cmdline(NULL, getexline, NULL, DOCMD_NOWAIT|DOCMD_VERBOSE);
+    do_cmdline(NULL, getexline, NULL, DOCMD_NOWAIT|DOCMD_VERBOSE);
   }
 
   exec_from_reg = save_efr;
@@ -6227,7 +6225,7 @@ static void ex_redir(exarg_T *eap)
       }
 
       if (var_redir_start(skipwhite(arg), append) == OK) {
-        redir_vname = 1;
+        redir_vname = true;
       }
     } else {  // TODO(vim): redirect to a buffer
       semsg(_(e_invarg2), eap->arg);
@@ -6333,7 +6331,7 @@ static void close_redir(void)
   redir_reg = 0;
   if (redir_vname) {
     var_redir_stop();
-    redir_vname = 0;
+    redir_vname = false;
   }
 }
 
@@ -7174,7 +7172,7 @@ static void ex_shada(exarg_T *eap)
     p_shada = "'100";
   }
   if (eap->cmdidx == CMD_rviminfo || eap->cmdidx == CMD_rshada) {
-    (void)shada_read_everything(eap->arg, eap->forceit, false);
+    shada_read_everything(eap->arg, eap->forceit, false);
   } else {
     shada_write_file(eap->arg, eap->forceit);
   }
@@ -7245,7 +7243,7 @@ static void ex_filetype(exarg_T *eap)
       }
     }
     if (*arg == 'd') {
-      (void)do_doautocmd("filetypedetect BufRead", true, NULL);
+      do_doautocmd("filetypedetect BufRead", true, NULL);
       do_modelines(0);
     }
   } else if (strcmp(arg, "off") == 0) {
diff --git a/src/nvim/ex_eval.c b/src/nvim/ex_eval.c
index c239e8a9ea..fd41ea1b91 100644
--- a/src/nvim/ex_eval.c
+++ b/src/nvim/ex_eval.c
@@ -105,7 +105,7 @@ static bool cause_abort = false;
 /// That is, during cancellation of an expression evaluation after an aborting
 /// function call or due to a parsing error, aborting() always returns the same
 /// value. "got_int" is also set by calling interrupt().
-int aborting(void)
+bool aborting(void)
 {
   return (did_emsg && force_abort) || got_int || did_throw;
 }
@@ -125,7 +125,7 @@ void update_force_abort(void)
 /// abort the script processing.  Can be used to suppress an autocommand after
 /// execution of a failing subcommand as long as the error message has not been
 /// displayed and actually caused the abortion.
-int should_abort(int retcode)
+bool should_abort(int retcode)
 {
   return (retcode == FAIL && trylevel != 0 && !emsg_silent) || aborting();
 }
@@ -134,7 +134,7 @@ int should_abort(int retcode)
 /// ended on an error.  This means that parsing commands is continued in order
 /// to find finally clauses to be executed, and that some errors in skipped
 /// commands are still reported.
-int aborted_in_try(void)
+bool aborted_in_try(void)
   FUNC_ATTR_PURE
 {
   // This function is only called after an error.  In this case, "force_abort"
@@ -326,7 +326,7 @@ void do_errthrow(cstack_T *cstack, char *cmdname)
 ///
 /// @return  true if the current exception is discarded or,
 ///          false otherwise.
-int do_intthrow(cstack_T *cstack)
+bool do_intthrow(cstack_T *cstack)
 {
   // If no interrupt occurred or no try conditional is active and no exception
   // is being thrown, do nothing (for compatibility of non-EH scripts).
@@ -369,7 +369,7 @@ int do_intthrow(cstack_T *cstack)
 }
 
 /// Get an exception message that is to be stored in current_exception->value.
-char *get_exception_string(void *value, except_type_T type, char *cmdname, int *should_free)
+char *get_exception_string(void *value, except_type_T type, char *cmdname, bool *should_free)
 {
   char *ret;
 
@@ -454,7 +454,7 @@ static int throw_exception(void *value, except_type_T type, char *cmdname)
     excp->messages = (msglist_T *)value;
   }
 
-  int should_free;
+  bool should_free;
   excp->value = get_exception_string(value, type, cmdname, &should_free);
   if (excp->value == NULL && should_free) {
     goto nomem;
@@ -841,7 +841,7 @@ void ex_if(exarg_T *eap)
     cstack->cs_idx++;
     cstack->cs_flags[cstack->cs_idx] = 0;
 
-    int skip = CHECK_SKIP;
+    bool skip = CHECK_SKIP;
 
     bool error;
     bool result = eval_to_bool(eap->arg, &error, eap, skip);
@@ -875,7 +875,7 @@ void ex_endif(exarg_T *eap)
     // discarded by throwing the interrupt exception later on.
     if (!(eap->cstack->cs_flags[eap->cstack->cs_idx] & CSF_TRUE)
         && dbg_check_skipped(eap)) {
-      (void)do_intthrow(eap->cstack);
+      do_intthrow(eap->cstack);
     }
 
     eap->cstack->cs_idx--;
@@ -926,7 +926,7 @@ void ex_else(exarg_T *eap)
   // for a parsing errors is discarded when throwing the interrupt exception
   // later on.
   if (!skip && dbg_check_skipped(eap) && got_int) {
-    (void)do_intthrow(cstack);
+    do_intthrow(cstack);
     skip = true;
   }
 
@@ -1132,7 +1132,7 @@ void ex_endwhile(exarg_T *eap)
         }
       }
       // Cleanup and rewind all contained (and unclosed) conditionals.
-      (void)cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, false);
+      cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, false);
       rewind_conditionals(cstack, idx, CSF_TRY, &cstack->cs_trylevel);
     } else if (cstack->cs_flags[cstack->cs_idx] & CSF_TRUE
                && !(cstack->cs_flags[cstack->cs_idx] & CSF_ACTIVE)
@@ -1145,7 +1145,7 @@ void ex_endwhile(exarg_T *eap)
       // throw an interrupt exception if appropriate.  Doing this here
       // prevents that an exception for a parsing error is discarded when
       // throwing the interrupt exception later on.
-      (void)do_intthrow(cstack);
+      do_intthrow(cstack);
     }
 
     // Set loop flag, so do_cmdline() will jump back to the matching
@@ -1476,7 +1476,7 @@ void ex_finally(exarg_T *eap)
       // occurred before the ":finally".  That is, discard the
       // original exception and replace it by an interrupt
       // exception.
-      (void)do_intthrow(cstack);
+      do_intthrow(cstack);
     }
 
     // If there is a preceding catch clause and it caught the exception,
@@ -1617,7 +1617,7 @@ void ex_endtry(exarg_T *eap)
     // set "skip" and "rethrow".
     if (got_int) {
       skip = true;
-      (void)do_intthrow(cstack);
+      do_intthrow(cstack);
       // The do_intthrow() call may have reset did_throw or
       // cstack->cs_pending[idx].
       rethrow = false;
@@ -1649,7 +1649,7 @@ void ex_endtry(exarg_T *eap)
   // was no finally clause, finish the exception now.  This happens also
   // after errors except when this ":endtry" is not within a ":try".
   // Restore "emsg_silent" if it has been reset by this try conditional.
-  (void)cleanup_conditionals(cstack, CSF_TRY | CSF_SILENT, true);
+  cleanup_conditionals(cstack, CSF_TRY | CSF_SILENT, true);
 
   if (cstack->cs_idx >= 0 && (cstack->cs_flags[cstack->cs_idx] & CSF_TRY)) {
     cstack->cs_idx--;
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 84e527b08c..ddb8beaf6f 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -467,7 +467,7 @@ static void may_do_incsearch_highlighting(int firstc, int count, incsearch_state
 
     // if interrupted while searching, behave like it failed
     if (got_int) {
-      (void)vpeekc();               // remove <C-C> from input stream
+      vpeekc();               // remove <C-C> from input stream
       got_int = false;              // don't abandon the command line
       found = 0;
     } else if (char_avail()) {
@@ -1052,7 +1052,7 @@ static int command_line_wildchar_complete(CommandLineState *s)
         && !s->did_wild_list
         && ((wim_flags[s->wim_index] & WIM_LIST)
             || (p_wmnu && (wim_flags[s->wim_index] & WIM_FULL) != 0))) {
-      (void)showmatches(&s->xpc, p_wmnu && ((wim_flags[s->wim_index] & WIM_LIST) == 0));
+      showmatches(&s->xpc, p_wmnu && ((wim_flags[s->wim_index] & WIM_LIST) == 0));
       redrawcmd();
       s->did_wild_list = true;
     }
@@ -1078,9 +1078,9 @@ static int command_line_wildchar_complete(CommandLineState *s)
 
     // if interrupted while completing, behave like it failed
     if (got_int) {
-      (void)vpeekc();               // remove <C-C> from input stream
+      vpeekc();               // remove <C-C> from input stream
       got_int = false;              // don't abandon the command line
-      (void)ExpandOne(&s->xpc, NULL, NULL, 0, WILD_FREE);
+      ExpandOne(&s->xpc, NULL, NULL, 0, WILD_FREE);
       s->xpc.xp_context = EXPAND_NOTHING;
       return CMDLINE_CHANGED;
     }
@@ -1104,7 +1104,7 @@ static int command_line_wildchar_complete(CommandLineState *s)
           p_wmnu = p_wmnu_save;
         }
 
-        (void)showmatches(&s->xpc, p_wmnu && ((wim_flags[s->wim_index] & WIM_LIST) == 0));
+        showmatches(&s->xpc, p_wmnu && ((wim_flags[s->wim_index] & WIM_LIST) == 0));
         redrawcmd();
         s->did_wild_list = true;
 
@@ -1138,7 +1138,7 @@ static void command_line_end_wildmenu(CommandLineState *s)
     cmdline_pum_remove();
   }
   if (s->xpc.xp_numfiles != -1) {
-    (void)ExpandOne(&s->xpc, NULL, NULL, 0, WILD_FREE);
+    ExpandOne(&s->xpc, NULL, NULL, 0, WILD_FREE);
   }
   s->did_wild_list = false;
   if (!p_wmnu || (s->c != K_UP && s->c != K_DOWN)) {
@@ -1250,7 +1250,7 @@ static int command_line_execute(VimState *state, int key)
     // Ctrl-E: cancel the cmdline popup menu and return the original text.
     if (s->c == Ctrl_E || s->c == Ctrl_Y) {
       wild_type = (s->c == Ctrl_E) ? WILD_CANCEL : WILD_APPLY;
-      (void)nextwild(&s->xpc, wild_type, WILD_NO_BEEP, s->firstc != '@');
+      nextwild(&s->xpc, wild_type, WILD_NO_BEEP, s->firstc != '@');
     }
   }
 
@@ -1419,7 +1419,7 @@ static int may_do_command_line_next_incsearch(int firstc, int count, incsearch_s
     if (lt(s->match_start, s->match_end)) {
       // start searching at the end of the match
       // not at the beginning of the next column
-      (void)decl(&t);
+      decl(&t);
     }
     search_flags += SEARCH_COL;
   } else {
@@ -1447,21 +1447,21 @@ static int may_do_command_line_next_incsearch(int firstc, int count, incsearch_s
       // when nv_search finishes the cursor will be
       // put back on the match
       s->search_start = t;
-      (void)decl(&s->search_start);
+      decl(&s->search_start);
     } else if (next_match && firstc == '?') {
       // move just after the current match, so that
       // when nv_search finishes the cursor will be
       // put back on the match
       s->search_start = t;
-      (void)incl(&s->search_start);
+      incl(&s->search_start);
     }
     if (lt(t, s->search_start) && next_match) {
       // wrap around
       s->search_start = t;
       if (firstc == '?') {
-        (void)incl(&s->search_start);
+        incl(&s->search_start);
       } else {
-        (void)decl(&s->search_start);
+        decl(&s->search_start);
       }
     }
 
@@ -2176,7 +2176,7 @@ static bool empty_pattern(char *p, int delim)
   magic_T magic_val = MAGIC_ON;
 
   if (n > 0) {
-    (void)skip_regexp_ex(p, delim, magic_isset(), NULL, NULL, &magic_val);
+    skip_regexp_ex(p, delim, magic_isset(), NULL, NULL, &magic_val);
   } else {
     return true;
   }
@@ -2939,7 +2939,7 @@ char *getexline(int c, void *cookie, int indent, bool do_concat)
 {
   // When executing a register, remove ':' that's in front of each line.
   if (exec_from_reg && vpeekc() == ':') {
-    (void)vgetc();
+    vgetc();
   }
 
   return getcmdline(c, 1, indent, do_concat);
@@ -3454,7 +3454,7 @@ void cmdline_ui_flush(void)
 // Put a character on the command line.  Shifts the following text to the
 // right when "shift" is true.  Used for CTRL-V, CTRL-K, etc.
 // "c" must be printable (fit in one display cell)!
-void putcmdline(char c, int shift)
+void putcmdline(char c, bool shift)
 {
   if (cmd_silent) {
     return;
@@ -3501,7 +3501,7 @@ void unputcmdline(void)
 // part will be redrawn, otherwise it will not.  If this function is called
 // twice in a row, then 'redraw' should be false and redrawcmd() should be
 // called afterwards.
-void put_on_cmdline(const char *str, int len, int redraw)
+void put_on_cmdline(const char *str, int len, bool redraw)
 {
   int i;
   int m;
@@ -3711,7 +3711,7 @@ static bool cmdline_paste(int regname, bool literally, bool remcr)
 // When "literally" is true, insert literally.
 // When "literally" is false, insert as typed, but don't leave the command
 // line.
-void cmdline_paste_str(const char *s, int literally)
+void cmdline_paste_str(const char *s, bool literally)
 {
   if (literally) {
     put_on_cmdline(s, -1, true);
diff --git a/src/nvim/ex_session.c b/src/nvim/ex_session.c
index 98869c0a25..887a0356c1 100644
--- a/src/nvim/ex_session.c
+++ b/src/nvim/ex_session.c
@@ -212,7 +212,7 @@ static int ses_do_win(win_T *wp)
 /// @param flagp
 ///
 /// @returns FAIL if writing fails.
-static int ses_arglist(FILE *fd, char *cmd, garray_T *gap, int fullname, unsigned *flagp)
+static int ses_arglist(FILE *fd, char *cmd, garray_T *gap, bool fullname, unsigned *flagp)
 {
   char *buf = NULL;
 
@@ -225,7 +225,7 @@ static int ses_arglist(FILE *fd, char *cmd, garray_T *gap, int fullname, unsigne
     if (s != NULL) {
       if (fullname) {
         buf = xmalloc(MAXPATHL);
-        (void)vim_FullName(s, buf, MAXPATHL, false);
+        vim_FullName(s, buf, MAXPATHL, false);
         s = buf;
       }
       char *fname_esc = ses_escape_fname(s, flagp);
@@ -322,7 +322,7 @@ static int put_view(FILE *fd, win_T *wp, int add_edit, unsigned *flagp, int curr
 
   // Always restore cursor position for ":mksession".  For ":mkview" only
   // when 'viewoptions' contains "cursor".
-  int do_cursor = (flagp == &ssop_flags || *flagp & SSOP_CURSOR);
+  bool do_cursor = (flagp == &ssop_flags || *flagp & SSOP_CURSOR);
 
   // Local argument list.
   if (wp->w_alist == &global_alist) {
@@ -975,7 +975,7 @@ void ex_mkrc(exarg_T *eap)
 
   FILE *fd = open_exfile(fname, eap->forceit, WRITEBIN);
   if (fd != NULL) {
-    int failed = false;
+    bool failed = false;
     unsigned *flagp;
     if (eap->cmdidx == CMD_mkview) {
       flagp = &vop_flags;
@@ -985,7 +985,7 @@ void ex_mkrc(exarg_T *eap)
 
     // Write the version command for :mkvimrc
     if (eap->cmdidx == CMD_mkvimrc) {
-      (void)put_line(fd, "version 6.0");
+      put_line(fd, "version 6.0");
     }
 
     if (eap->cmdidx == CMD_mksession) {
diff --git a/src/nvim/file_search.c b/src/nvim/file_search.c
index 76f7b7e1af..6be9556951 100644
--- a/src/nvim/file_search.c
+++ b/src/nvim/file_search.c
@@ -238,7 +238,6 @@ static const char e_path_too_long_for_completion[]
 void *vim_findfile_init(char *path, char *filename, char *stopdirs, int level, int free_visited,
                         int find_what, void *search_ctx_arg, int tagfile, char *rel_fname)
 {
-  char *wc_part;
   ff_stack_T *sptr;
   ff_search_ctx_T *search_ctx;
 
@@ -373,7 +372,7 @@ void *vim_findfile_init(char *path, char *filename, char *stopdirs, int level, i
   // split into:
   //  -fix path
   //  -wildcard_stuff (might be NULL)
-  wc_part = vim_strchr(path, '*');
+  char *wc_part = vim_strchr(path, '*');
   if (wc_part != NULL) {
     int64_t llevel;
     int len;
@@ -549,24 +548,22 @@ void vim_findfile_cleanup(void *ctx)
 ///          NULL if nothing found.
 char *vim_findfile(void *search_ctx_arg)
 {
-  char *file_path;
   char *rest_of_wildcards;
   char *path_end = NULL;
   ff_stack_T *stackp = NULL;
   size_t len;
   char *p;
   char *suf;
-  ff_search_ctx_T *search_ctx;
 
   if (search_ctx_arg == NULL) {
     return NULL;
   }
 
-  search_ctx = (ff_search_ctx_T *)search_ctx_arg;
+  ff_search_ctx_T *search_ctx = (ff_search_ctx_T *)search_ctx_arg;
 
   // filepath is used as buffer for various actions and as the storage to
   // return a found filename.
-  file_path = xmalloc(MAXPATHL);
+  char *file_path = xmalloc(MAXPATHL);
 
   // store the end of the start dir -- needed for upward search
   if (search_ctx->ffsc_start_dir != NULL) {
@@ -929,13 +926,11 @@ fail:
 /// Can handle it if the passed search_context is NULL;
 void vim_findfile_free_visited(void *search_ctx_arg)
 {
-  ff_search_ctx_T *search_ctx;
-
   if (search_ctx_arg == NULL) {
     return;
   }
 
-  search_ctx = (ff_search_ctx_T *)search_ctx_arg;
+  ff_search_ctx_T *search_ctx = (ff_search_ctx_T *)search_ctx_arg;
   vim_findfile_free_visited_list(&search_ctx->ffsc_visited_lists_list);
   vim_findfile_free_visited_list(&search_ctx->ffsc_dir_visited_lists_list);
 }
@@ -1157,9 +1152,7 @@ static void ff_push(ff_search_ctx_T *search_ctx, ff_stack_T *stack_ptr)
 /// @return  NULL if stack is empty.
 static ff_stack_T *ff_pop(ff_search_ctx_T *search_ctx)
 {
-  ff_stack_T *sptr;
-
-  sptr = search_ctx->ffsc_stack_ptr;
+  ff_stack_T *sptr = search_ctx->ffsc_stack_ptr;
   if (search_ctx->ffsc_stack_ptr != NULL) {
     search_ctx->ffsc_stack_ptr = search_ctx->ffsc_stack_ptr->ffs_prev;
   }
@@ -1224,8 +1217,6 @@ static void ff_clear(ff_search_ctx_T *search_ctx)
 /// @return  true if yes else false
 static bool ff_path_in_stoplist(char *path, int path_len, char **stopdirs_v)
 {
-  int i = 0;
-
   // eat up trailing path separators, except the first
   while (path_len > 1 && vim_ispathsep(path[path_len - 1])) {
     path_len--;
@@ -1236,7 +1227,7 @@ static bool ff_path_in_stoplist(char *path, int path_len, char **stopdirs_v)
     return true;
   }
 
-  for (i = 0; stopdirs_v[i] != NULL; i++) {
+  for (int i = 0; stopdirs_v[i] != NULL; i++) {
     if ((int)strlen(stopdirs_v[i]) > path_len) {
       // match for parent directory. So '/home' also matches
       // '/home/rks'. Check for PATHSEP in stopdirs_v[i], else
diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index 3e8c4f694c..008cd9c222 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -156,14 +156,12 @@ int readfile(char *fname, char *sfname, linenr_T from, linenr_T lines_to_skip,
 {
   int retval = FAIL;  // jump to "theend" instead of returning
   int fd = stdin_fd >= 0 ? stdin_fd : 0;
-  int newfile = (flags & READ_NEW);
-  int check_readonly;
-  int filtering = (flags & READ_FILTER);
-  int read_stdin = (flags & READ_STDIN);
-  int read_buffer = (flags & READ_BUFFER);
-  int read_fifo = (flags & READ_FIFO);
-  int set_options = newfile || read_buffer
-                    || (eap != NULL && eap->read_edit);
+  bool newfile = (flags & READ_NEW);
+  bool filtering = (flags & READ_FILTER);
+  bool read_stdin = (flags & READ_STDIN);
+  bool read_buffer = (flags & READ_BUFFER);
+  bool read_fifo = (flags & READ_FIFO);
+  bool set_options = newfile || read_buffer || (eap != NULL && eap->read_edit);
   linenr_T read_buf_lnum = 1;           // next line to read from curbuf
   colnr_T read_buf_col = 0;             // next char to read from this line
   char c;
@@ -198,7 +196,6 @@ int readfile(char *fname, char *sfname, linenr_T from, linenr_T lines_to_skip,
   linenr_T read_no_eol_lnum = 0;        // non-zero lnum when last line of
                                         // last read was missing the eol
   bool file_rewind = false;
-  int can_retry;
   linenr_T conv_error = 0;              // line nr with conversion error
   linenr_T illegal_byte = 0;            // line nr with illegal byte
   bool keep_dest_enc = false;           // don't retry when char doesn't fit
@@ -386,7 +383,7 @@ int readfile(char *fname, char *sfname, linenr_T from, linenr_T lines_to_skip,
   // Default is r/w, can be set to r/o below.
   // Don't reset it when in readonly mode
   // Only set/reset b_p_ro when BF_CHECK_RO is set.
-  check_readonly = (newfile && (curbuf->b_flags & BF_CHECK_RO));
+  bool check_readonly = (newfile && (curbuf->b_flags & BF_CHECK_RO));
   if (check_readonly && !readonlymode) {
     curbuf->b_p_ro = false;
   }
@@ -557,7 +554,7 @@ int readfile(char *fname, char *sfname, linenr_T from, linenr_T lines_to_skip,
         }
       }
 
-      (void)os_setperm(swap_fname, swap_mode);
+      os_setperm(swap_fname, swap_mode);
     }
 #endif
   }
@@ -851,7 +848,7 @@ retry:
   // Set "can_retry" when it's possible to rewind the file and try with
   // another "fenc" value.  It's false when no other "fenc" to try, reading
   // stdin or fixed at a specific encoding.
-  can_retry = (*fenc != NUL && !read_stdin && !keep_dest_enc && !read_fifo);
+  bool can_retry = (*fenc != NUL && !read_stdin && !keep_dest_enc && !read_fifo);
 
   if (!skip_read) {
     linerest = 0;
@@ -1149,7 +1146,6 @@ retry:
 
       if (fio_flags != 0) {
         unsigned u8c;
-        char *dest;
         char *tail = NULL;
 
         // Convert Unicode or Latin1 to UTF-8.
@@ -1157,7 +1153,7 @@ retry:
         // of bytes may increase.
         // "dest" points to after where the UTF-8 bytes go, "p" points
         // to after the next character to convert.
-        dest = ptr + real_size;
+        char *dest = ptr + real_size;
         if (fio_flags == FIO_LATIN1 || fio_flags == FIO_UTF8) {
           p = (uint8_t *)ptr + size;
           if (fio_flags == FIO_UTF8) {
@@ -1313,7 +1309,7 @@ retry:
           assert(u8c <= INT_MAX);
           // produce UTF-8
           dest -= utf_char2len((int)u8c);
-          (void)utf_char2bytes((int)u8c, dest);
+          utf_char2bytes((int)u8c, dest);
         }
 
         // move the linerest to before the converted characters
@@ -1530,8 +1526,7 @@ rewind_retry:
                 // Otherwise give an error message later.
                 if (try_unix
                     && !read_stdin
-                    && (read_buffer
-                        || vim_lseek(fd, 0, SEEK_SET) == 0)) {
+                    && (read_buffer || vim_lseek(fd, 0, SEEK_SET) == 0)) {
                   fileformat = EOL_UNIX;
                   if (set_options) {
                     set_fileformat(EOL_UNIX, OPT_LOCAL);
@@ -1628,7 +1623,7 @@ failed:
   if (!read_buffer && !read_stdin) {
     close(fd);  // errors are ignored
   } else {
-    (void)os_set_cloexec(fd);
+    os_set_cloexec(fd);
   }
   xfree(buffer);
 
@@ -1936,7 +1931,7 @@ void prep_exarg(exarg_T *eap, const buf_T *buf)
 }
 
 /// Set default or forced 'fileformat' and 'binary'.
-void set_file_options(int set_options, exarg_T *eap)
+void set_file_options(bool set_options, exarg_T *eap)
 {
   // set default 'fileformat'
   if (set_options) {
@@ -2096,7 +2091,7 @@ int set_rw_fname(char *fname, char *sfname)
   // Do filetype detection now if 'filetype' is empty.
   if (*curbuf->b_p_ft == NUL) {
     if (augroup_exists("filetypedetect")) {
-      (void)do_doautocmd("filetypedetect BufRead", false, NULL);
+      do_doautocmd("filetypedetect BufRead", false, NULL);
     }
     do_modelines(0);
   }
@@ -2197,7 +2192,7 @@ bool time_differs(const FileInfo *file_info, int64_t mtime, int64_t mtime_ns)
 bool need_conversion(const char *fenc)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  int same_encoding;
+  bool same_encoding;
   int fenc_flags;
 
   if (*fenc == NUL || strcmp(p_enc, fenc) == 0) {
@@ -2634,7 +2629,7 @@ static int rename_with_tmp(const char *const from, const char *const to)
         }
         // Strange, the second step failed.  Try moving the
         // file back and return failure.
-        (void)os_rename(tempname, from);
+        os_rename(tempname, from);
         return -1;
       }
       // If it fails for one temp name it will most likely fail
@@ -3045,7 +3040,7 @@ int buf_check_timestamp(buf_T *buf)
           msg_puts_attr(mesg2, HL_ATTR(HLF_W) + MSG_HIST);
         }
         msg_clr_eos();
-        (void)msg_end();
+        msg_end();
         if (emsg_silent == 0 && !in_assert_fails) {
           ui_flush();
           // give the user some time to think about it
@@ -3076,7 +3071,7 @@ int buf_check_timestamp(buf_T *buf)
 
   // Trigger FileChangedShell when the file was changed in any way.
   if (bufref_valid(&bufref) && retval != 0) {
-    (void)apply_autocmds(EVENT_FILECHANGEDSHELLPOST, buf->b_fname, buf->b_fname, false, buf);
+    apply_autocmds(EVENT_FILECHANGEDSHELLPOST, buf->b_fname, buf->b_fname, false, buf);
   }
   return retval;
 }
@@ -3161,7 +3156,7 @@ void buf_reload(buf_T *buf, int orig_mode, bool reload_options)
             break;
           }
         }
-        (void)move_lines(savebuf, buf);
+        move_lines(savebuf, buf);
       }
     } else if (buf == curbuf) {  // "buf" still valid.
       // Mark the buffer as unmodified and free undo info.
@@ -3276,7 +3271,7 @@ static void vim_mktempdir(void)
   char user[40] = { 0 };
   char appname[40] = { 0 };
 
-  (void)os_get_username(user, sizeof(user));
+  os_get_username(user, sizeof(user));
   // Usernames may contain slashes! #19240
   memchrsub(user, '/', '_', sizeof(user));
   memchrsub(user, '\\', '_', sizeof(user));
@@ -3302,7 +3297,7 @@ static void vim_mktempdir(void)
     xstrlcat(tmp, appname, sizeof(tmp));
     xstrlcat(tmp, ".", sizeof(tmp));
     xstrlcat(tmp, user, sizeof(tmp));
-    (void)os_mkdir(tmp, 0700);  // Always create, to avoid a race.
+    os_mkdir(tmp, 0700);  // Always create, to avoid a race.
     bool owned = os_file_owned(tmp);
     bool isdir = os_isdir(tmp);
 #ifdef UNIX
@@ -3344,7 +3339,7 @@ static void vim_mktempdir(void)
     // Couldn't set `vim_tempdir` to `path` so remove created directory.
     os_rmdir(path);
   }
-  (void)umask(umask_save);
+  umask(umask_save);
 }
 
 /// Core part of "readdir()" function.
diff --git a/src/nvim/fold.c b/src/nvim/fold.c
index 3b7662e62d..863c61d958 100644
--- a/src/nvim/fold.c
+++ b/src/nvim/fold.c
@@ -371,7 +371,7 @@ void closeFold(pos_T pos, int count)
 /// Close fold for current window at position `pos` recursively.
 void closeFoldRecurse(pos_T pos)
 {
-  (void)setManualFold(pos, false, true, NULL);
+  setManualFold(pos, false, true, NULL);
 }
 
 // opFoldRange() {{{2
@@ -382,7 +382,7 @@ void closeFoldRecurse(pos_T pos)
 /// @param opening     true to open, false to close
 /// @param recurse     true to do it recursively
 /// @param had_visual  true when Visual selection used
-void opFoldRange(pos_T firstpos, pos_T lastpos, int opening, int recurse, int had_visual)
+void opFoldRange(pos_T firstpos, pos_T lastpos, int opening, int recurse, bool had_visual)
 {
   int done = DONE_NOTHING;              // avoid error messages
   linenr_T first = firstpos.lnum;
@@ -395,13 +395,13 @@ void opFoldRange(pos_T firstpos, pos_T lastpos, int opening, int recurse, int ha
     // Opening one level only: next fold to open is after the one going to
     // be opened.
     if (opening && !recurse) {
-      (void)hasFolding(lnum, NULL, &lnum_next);
+      hasFolding(lnum, NULL, &lnum_next);
     }
-    (void)setManualFold(temp, opening, recurse, &done);
+    setManualFold(temp, opening, recurse, &done);
     // Closing one level only: next line to close a fold is after just
     // closed fold.
     if (!opening && !recurse) {
-      (void)hasFolding(lnum, NULL, &lnum_next);
+      hasFolding(lnum, NULL, &lnum_next);
     }
   }
   if (done == DONE_NOTHING) {
@@ -425,7 +425,7 @@ void openFold(pos_T pos, int count)
 /// Open fold for current window at position `pos` recursively.
 void openFoldRecurse(pos_T pos)
 {
-  (void)setManualFold(pos, true, true, NULL);
+  setManualFold(pos, true, true, NULL);
 }
 
 // foldOpenCursor() {{{2
@@ -436,7 +436,7 @@ void foldOpenCursor(void)
   if (hasAnyFolding(curwin)) {
     while (true) {
       int done = DONE_NOTHING;
-      (void)setManualFold(curwin->w_cursor, true, false, &done);
+      setManualFold(curwin->w_cursor, true, false, &done);
       if (!(done & DONE_ACTION)) {
         break;
       }
@@ -793,7 +793,7 @@ void foldUpdate(win_T *wp, linenr_T top, linenr_T bot)
       maybe_small_end = top;
     }
     fold_T *fp;
-    (void)foldFind(&wp->w_folds, maybe_small_start, &fp);
+    foldFind(&wp->w_folds, maybe_small_start, &fp);
     while (fp < (fold_T *)wp->w_folds.ga_data + wp->w_folds.ga_len
            && fp->fd_top <= maybe_small_end) {
       fp->fd_small = kNone;
@@ -1027,7 +1027,7 @@ void foldAdjustVisual(void)
 /// Move the cursor to the first line of a closed fold.
 void foldAdjustCursor(void)
 {
-  (void)hasFolding(curwin->w_cursor.lnum, &curwin->w_cursor.lnum, NULL);
+  hasFolding(curwin->w_cursor.lnum, &curwin->w_cursor.lnum, NULL);
 }
 
 // Internal functions for "fold_T" {{{1
@@ -1137,7 +1137,7 @@ static void setFoldRepeat(pos_T pos, int count, int do_open)
 {
   for (int n = 0; n < count; n++) {
     int done = DONE_NOTHING;
-    (void)setManualFold(pos, do_open, false, &done);
+    setManualFold(pos, do_open, false, &done);
     if (!(done & DONE_ACTION)) {
       // Only give an error message when no fold could be opened.
       if (n == 0 && !(done & DONE_FOLD)) {
@@ -1154,7 +1154,7 @@ static void setFoldRepeat(pos_T pos, int count, int do_open)
 ///
 /// @param opening  true when opening, false when closing
 /// @param recurse  true when closing/opening recursive
-static linenr_T setManualFold(pos_T pos, int opening, int recurse, int *donep)
+static linenr_T setManualFold(pos_T pos, bool opening, bool recurse, int *donep)
 {
   if (foldmethodIsDiff(curwin) && curwin->w_p_scb) {
     linenr_T dlnum;
@@ -1165,7 +1165,7 @@ static linenr_T setManualFold(pos_T pos, int opening, int recurse, int *donep)
       if (wp != curwin && foldmethodIsDiff(wp) && wp->w_p_scb) {
         dlnum = diff_lnum_win(curwin->w_cursor.lnum, wp);
         if (dlnum != 0) {
-          (void)setManualFoldWin(wp, dlnum, opening, recurse, NULL);
+          setManualFoldWin(wp, dlnum, opening, recurse, NULL);
         }
       }
     }
@@ -1186,7 +1186,7 @@ static linenr_T setManualFold(pos_T pos, int opening, int recurse, int *donep)
 ///
 /// @return         the line number of the next line that could be closed.
 ///                 It's only valid when "opening" is true!
-static linenr_T setManualFoldWin(win_T *wp, linenr_T lnum, int opening, int recurse, int *donep)
+static linenr_T setManualFoldWin(win_T *wp, linenr_T lnum, bool opening, bool recurse, int *donep)
 {
   fold_T *fp;
   fold_T *fp2;
@@ -1387,7 +1387,7 @@ static void foldMarkAdjustRecurse(win_T *wp, garray_T *gap, linenr_T line1, line
 
   // Find the fold containing or just below "line1".
   fold_T *fp;
-  (void)foldFind(gap, line1, &fp);
+  foldFind(gap, line1, &fp);
 
   // Adjust all folds below "line1" that are affected.
   for (int i = (int)(fp - (fold_T *)gap->ga_data); i < gap->ga_len; i++, fp++) {
@@ -1634,7 +1634,7 @@ static void foldAddMarker(buf_T *buf, pos_T pos, const char *marker, size_t mark
 /// Delete the markers for a fold, causing it to be deleted.
 ///
 /// @param lnum_off  offset for fp->fd_top
-static void deleteFoldMarkers(win_T *wp, fold_T *fp, int recursive, linenr_T lnum_off)
+static void deleteFoldMarkers(win_T *wp, fold_T *fp, bool recursive, linenr_T lnum_off)
 {
   if (recursive) {
     for (int i = 0; i < fp->fd_nested.ga_len; i++) {
@@ -2169,7 +2169,7 @@ static linenr_T foldUpdateIEMSRecurse(garray_T *const gap, const int level,
   // startlnum, it must be deleted.
   if (getlevel == foldlevelMarker && flp->start <= flp->lvl - level
       && flp->lvl > 0) {
-    (void)foldFind(gap, startlnum - 1, &fp);
+    foldFind(gap, startlnum - 1, &fp);
     if (fp != NULL
         && (fp >= ((fold_T *)gap->ga_data) + gap->ga_len
             || fp->fd_top >= startlnum)) {
@@ -2235,7 +2235,7 @@ static linenr_T foldUpdateIEMSRecurse(garray_T *const gap, const int level,
         }
       }
       if (lvl < level + i) {
-        (void)foldFind(&fp->fd_nested, flp->lnum - fp->fd_top, &fp2);
+        foldFind(&fp->fd_nested, flp->lnum - fp->fd_top, &fp2);
         if (fp2 != NULL) {
           bot = fp2->fd_top + fp2->fd_len - 1 + fp->fd_top;
         }
@@ -2601,7 +2601,7 @@ static void foldSplit(buf_T *buf, garray_T *const gap, const int i, const linenr
   // any between top and bot, they have been removed by the caller.
   garray_T *const gap1 = &fp->fd_nested;
   garray_T *const gap2 = &fp[1].fd_nested;
-  (void)foldFind(gap1, bot + 1 - fp->fd_top, &fp2);
+  foldFind(gap1, bot + 1 - fp->fd_top, &fp2);
   if (fp2 != NULL) {
     const int len = (int)((fold_T *)gap1->ga_data + gap1->ga_len - fp2);
     if (len > 0) {
@@ -3232,7 +3232,7 @@ static int put_fold_open_close(FILE *fd, fold_T *fp, linenr_T off)
 // }}}1
 
 /// "foldclosed()" and "foldclosedend()" functions
-static void foldclosed_both(typval_T *argvars, typval_T *rettv, int end)
+static void foldclosed_both(typval_T *argvars, typval_T *rettv, bool end)
 {
   const linenr_T lnum = tv_get_lnum(argvars);
   if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count) {
diff --git a/src/nvim/getchar.c b/src/nvim/getchar.c
index 5d6a220ec7..6842aeddcb 100644
--- a/src/nvim/getchar.c
+++ b/src/nvim/getchar.c
@@ -188,15 +188,12 @@ static char *get_buffcont(buffheader_T *buffer, int dozero)
 /// K_SPECIAL in the returned string is escaped.
 char *get_recorded(void)
 {
-  char *p;
-  size_t len;
-
-  p = get_buffcont(&recordbuff, true);
+  char *p = get_buffcont(&recordbuff, true);
   free_buff(&recordbuff);
 
   // Remove the characters that were added the last time, these must be the
   // (possibly mapped) characters that stopped the recording.
-  len = strlen(p);
+  size_t len = strlen(p);
   if (len >= last_recorded_len) {
     len -= last_recorded_len;
     p[len] = NUL;
@@ -272,12 +269,10 @@ static void add_buff(buffheader_T *const buf, const char *const s, ptrdiff_t sle
 /// Only works when it was just added.
 static void delete_buff_tail(buffheader_T *buf, int slen)
 {
-  int len;
-
   if (buf->bh_curr == NULL) {
     return;  // nothing to delete
   }
-  len = (int)strlen(buf->bh_curr->b_str);
+  int len = (int)strlen(buf->bh_curr->b_str);
   if (len < slen) {
     return;
   }
@@ -331,18 +326,16 @@ static void add_char_buff(buffheader_T *buf, int c)
 /// if that one is empty.
 /// If advance == true go to the next char.
 /// No translation is done K_SPECIAL is escaped.
-static int read_readbuffers(int advance)
+static int read_readbuffers(bool advance)
 {
-  int c;
-
-  c = read_readbuf(&readbuf1, advance);
+  int c = read_readbuf(&readbuf1, advance);
   if (c == NUL) {
     c = read_readbuf(&readbuf2, advance);
   }
   return c;
 }
 
-static int read_readbuf(buffheader_T *buf, int advance)
+static int read_readbuf(buffheader_T *buf, bool advance)
 {
   if (buf->bh_first.b_next == NULL) {  // buffer is empty
     return NUL;
@@ -1000,7 +993,7 @@ int ins_char_typebuf(int c, int modifiers)
   unsigned len = special_to_buf(c, modifiers, true, buf);
   assert(len < sizeof(buf));
   buf[len] = NUL;
-  (void)ins_typebuf(buf, KeyNoremap, 0, !KeyTyped, cmd_silent);
+  ins_typebuf(buf, KeyNoremap, 0, !KeyTyped, cmd_silent);
   return (int)len;
 }
 
@@ -1314,7 +1307,6 @@ void openscript(char *name, bool directly)
   // always, "make test" would fail.
   if (directly) {
     oparg_T oa;
-    int oldcurscript;
     int save_State = State;
     int save_restart_edit = restart_edit;
     int save_finish_op = finish_op;
@@ -1326,11 +1318,11 @@ void openscript(char *name, bool directly)
     clear_oparg(&oa);
     finish_op = false;
 
-    oldcurscript = curscript;
+    int oldcurscript = curscript;
     do {
       update_topline_cursor();          // update cursor position and topline
       normal_cmd(&oa, false);           // execute one command
-      (void)vpeekc();                   // check for end of file
+      vpeekc();                   // check for end of file
     } while (scriptin[oldcurscript] != NULL);
 
     State = save_State;
@@ -1450,8 +1442,6 @@ int vgetc(void)
     mouse_row = old_mouse_row;
     mouse_col = old_mouse_col;
   } else {
-    int c2;
-    int n;
     // number of characters recorded from the last vgetc() call
     static size_t last_vgetc_recorded_len = 0;
 
@@ -1481,7 +1471,7 @@ int vgetc(void)
         int save_allow_keys = allow_keys;
         no_mapping++;
         allow_keys = 0;                 // make sure BS is not found
-        c2 = vgetorpeek(true);          // no mapping for these chars
+        int c2 = vgetorpeek(true);          // no mapping for these chars
         c = vgetorpeek(true);
         no_mapping--;
         allow_keys = save_allow_keys;
@@ -1574,6 +1564,7 @@ int vgetc(void)
       // For a multi-byte character get all the bytes and return the
       // converted character.
       // Note: This will loop until enough bytes are received!
+      int n;
       if ((n = MB_BYTE2LEN_CHECK(c)) > 1) {
         no_mapping++;
         buf[0] = (uint8_t)c;
@@ -1582,8 +1573,8 @@ int vgetc(void)
           if (buf[i] == K_SPECIAL) {
             // Must be a K_SPECIAL - KS_SPECIAL - KE_FILLER sequence,
             // which represents a K_SPECIAL (0x80).
-            (void)vgetorpeek(true);  // skip KS_SPECIAL
-            (void)vgetorpeek(true);  // skip KE_FILLER
+            vgetorpeek(true);  // skip KS_SPECIAL
+            vgetorpeek(true);  // skip KE_FILLER
           }
         }
         no_mapping--;
@@ -1605,7 +1596,7 @@ int vgetc(void)
           && !is_mouse_key(c)) {
         mod_mask = 0;
         int len = ins_char_typebuf(c, 0);
-        (void)ins_char_typebuf(ESC, 0);
+        ins_char_typebuf(ESC, 0);
         ungetchars(len + 3);  // K_SPECIAL KS_MODIFIER MOD_MASK_ALT takes 3 more bytes
         continue;
       }
@@ -1637,9 +1628,7 @@ int vgetc(void)
 /// directly from the user (ignoring typeahead).
 int safe_vgetc(void)
 {
-  int c;
-
-  c = vgetc();
+  int c = vgetc();
   if (c == NUL) {
     c = get_keystroke(NULL);
   }
@@ -1677,9 +1666,7 @@ int vpeekc(void)
 /// buffer, it must be an ESC that is recognized as the start of a key code.
 int vpeekc_any(void)
 {
-  int c;
-
-  c = vpeekc();
+  int c = vpeekc();
   if (c == NUL && typebuf.tb_len > 0) {
     c = ESC;
   }
@@ -1690,10 +1677,8 @@ int vpeekc_any(void)
 /// @return  true if a character is available, false otherwise.
 bool char_avail(void)
 {
-  int retval;
-
   no_mapping++;
-  retval = vpeekc();
+  int retval = vpeekc();
   no_mapping--;
   return retval != NUL;
 }
@@ -1719,7 +1704,7 @@ static void getchar_common(typval_T *argvars, typval_T *rettv)
       if (!char_avail()) {
         // Flush screen updates before blocking.
         ui_flush();
-        (void)os_inchar(NULL, 0, -1, typebuf.tb_change_cnt, main_loop.events);
+        os_inchar(NULL, 0, -1, typebuf.tb_change_cnt, main_loop.events);
         if (!multiqueue_empty(main_loop.events)) {
           state_handle_k_event();
           continue;
@@ -1792,7 +1777,7 @@ static void getchar_common(typval_T *argvars, typval_T *rettv)
         if (win == NULL) {
           return;
         }
-        (void)mouse_comp_pos(win, &row, &col, &lnum);
+        mouse_comp_pos(win, &row, &col, &lnum);
         for (wp = firstwin; wp != win; wp = wp->w_next) {
           winnr++;
         }
@@ -1948,7 +1933,6 @@ static int handle_mapping(int *keylenp, const bool *timedout, int *mapdepth)
   mapblock_T *mp_match;
   int mp_match_len = 0;
   int max_mlen = 0;
-  int tb_c1;
   int keylen = *keylenp;
   int local_State = get_real_state();
   bool is_plug_map = false;
@@ -1972,7 +1956,7 @@ static int handle_mapping(int *keylenp, const bool *timedout, int *mapdepth)
   // - waiting for "hit return to continue" and CR or SPACE typed
   // - waiting for a char with --more--
   // - in Ctrl-X mode, and we get a valid char for that mode
-  tb_c1 = typebuf.tb_buf[typebuf.tb_off];
+  int tb_c1 = typebuf.tb_buf[typebuf.tb_off];
   if (no_mapping == 0
       && (no_zero_mapping == 0 || tb_c1 != '0')
       && (typebuf.tb_maplen == 0 || is_plug_map
@@ -2188,7 +2172,7 @@ static int handle_mapping(int *keylenp, const bool *timedout, int *mapdepth)
     // mode temporarily.  Append K_SELECT to switch back to Select mode.
     if (VIsual_active && VIsual_select && (mp->m_mode & MODE_VISUAL)) {
       VIsual_select = false;
-      (void)ins_typebuf(K_SELECT_STRING, REMAP_NONE, 0, true, false);
+      ins_typebuf(K_SELECT_STRING, REMAP_NONE, 0, true, false);
     }
 
     // Copy the values from *mp that are used, because evaluating the
@@ -2652,7 +2636,7 @@ static int vgetorpeek(bool advance)
               showcmd_idx = typebuf.tb_len - SHOWCMD_COLS;
             }
             while (showcmd_idx < typebuf.tb_len) {
-              (void)add_to_showcmd(typebuf.tb_buf[typebuf.tb_off + showcmd_idx++]);
+              add_to_showcmd(typebuf.tb_buf[typebuf.tb_off + showcmd_idx++]);
             }
             curwin->w_wcol = old_wcol;
             curwin->w_wrow = old_wrow;
@@ -2918,7 +2902,6 @@ char *getcmdkeycmd(int promptc, void *cookie, int indent, bool do_concat)
 {
   garray_T line_ga;
   int c1 = -1;
-  int c2;
   int cmod = 0;
   bool aborted = false;
 
@@ -2945,7 +2928,7 @@ char *getcmdkeycmd(int promptc, void *cookie, int indent, bool do_concat)
     // Get two extra bytes for special keys
     if (c1 == K_SPECIAL) {
       c1 = vgetorpeek(true);
-      c2 = vgetorpeek(true);
+      int c2 = vgetorpeek(true);
       if (c1 == KS_MODIFIER) {
         cmod = c2;
         continue;
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 3097853bea..50f3ef4010 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -600,10 +600,10 @@ EXTERN int u_sync_once INIT( = 0);       // Call u_sync() once when evaluating
 EXTERN bool force_restart_edit INIT( = false);  // force restart_edit after
                                                 // ex_normal returns
 EXTERN int restart_edit INIT( = 0);      // call edit when next cmd finished
-EXTERN int arrow_used;                  // Normally false, set to true after
-                                        // hitting cursor key in insert mode.
-                                        // Used by vgetorpeek() to decide when
-                                        // to call u_sync()
+EXTERN bool arrow_used;                  // Normally false, set to true after
+                                         // hitting cursor key in insert mode.
+                                         // Used by vgetorpeek() to decide when
+                                         // to call u_sync()
 EXTERN bool ins_at_eol INIT( = false);   // put cursor after eol when
                                          // restarting edit after CTRL-O
 
@@ -658,9 +658,9 @@ EXTERN bool typebuf_was_empty INIT( = false);
 EXTERN int ex_normal_busy INIT( = 0);      // recursiveness of ex_normal()
 EXTERN int expr_map_lock INIT( = 0);       // running expr mapping, prevent use of ex_normal() and text changes
 EXTERN bool ignore_script INIT( = false);  // ignore script input
-EXTERN int stop_insert_mode;              // for ":stopinsert"
-EXTERN bool KeyTyped;                     // true if user typed current char
-EXTERN int KeyStuffed;                    // true if current char from stuffbuf
+EXTERN bool stop_insert_mode;              // for ":stopinsert"
+EXTERN bool KeyTyped;                      // true if user typed current char
+EXTERN int KeyStuffed;                     // true if current char from stuffbuf
 EXTERN int maptick INIT( = 0);             // tick for each non-mapped char
 
 EXTERN int must_redraw INIT( = 0);           // type of redraw necessary
@@ -724,7 +724,7 @@ EXTERN char *empty_string_option INIT( = "");
 EXTERN bool redir_off INIT( = false);        // no redirection for a moment
 EXTERN FILE *redir_fd INIT( = NULL);         // message redirection file
 EXTERN int redir_reg INIT( = 0);             // message redirection register
-EXTERN int redir_vname INIT( = 0);           // message redirection variable
+EXTERN bool redir_vname INIT( = false);      // message redirection variable
 EXTERN garray_T *capture_ga INIT( = NULL);   // captured output for execute()
 
 EXTERN uint8_t langmap_mapchar[256];     // mapping for language keys
diff --git a/src/nvim/grid.c b/src/nvim/grid.c
index 37e538ea16..b4a6987213 100644
--- a/src/nvim/grid.c
+++ b/src/nvim/grid.c
@@ -263,13 +263,13 @@ void grid_clear_line(ScreenGrid *grid, size_t off, int width, bool valid)
     grid->chars[off + (size_t)col] = schar_from_ascii(' ');
   }
   int fill = valid ? 0 : -1;
-  (void)memset(grid->attrs + off, fill, (size_t)width * sizeof(sattr_T));
-  (void)memset(grid->vcols + off, -1, (size_t)width * sizeof(colnr_T));
+  memset(grid->attrs + off, fill, (size_t)width * sizeof(sattr_T));
+  memset(grid->vcols + off, -1, (size_t)width * sizeof(colnr_T));
 }
 
 void grid_invalidate(ScreenGrid *grid)
 {
-  (void)memset(grid->attrs, -1, sizeof(sattr_T) * (size_t)grid->rows * (size_t)grid->cols);
+  memset(grid->attrs, -1, sizeof(sattr_T) * (size_t)grid->rows * (size_t)grid->cols);
 }
 
 static bool grid_invalid_row(ScreenGrid *grid, int row)
diff --git a/src/nvim/hashtab.c b/src/nvim/hashtab.c
index e6a0e55ed2..68365cac5b 100644
--- a/src/nvim/hashtab.c
+++ b/src/nvim/hashtab.c
@@ -121,7 +121,7 @@ hashitem_T *hash_lookup(const hashtab_T *const ht, const char *const key, const
 {
 #ifdef HT_DEBUG
   hash_count_lookup++;
-#endif  // ifdef HT_DEBUG
+#endif
 
   // Quickly handle the most common situations:
   // - return if there is no item at all
@@ -154,7 +154,7 @@ hashitem_T *hash_lookup(const hashtab_T *const ht, const char *const key, const
 #ifdef HT_DEBUG
     // count a "miss" for hashtab lookup
     hash_count_perturb++;
-#endif  // ifdef HT_DEBUG
+#endif
     idx = 5 * idx + perturb + 1;
     hi = &ht->ht_array[idx & ht->ht_mask];
 
@@ -189,7 +189,7 @@ void hash_debug_results(void)
           (int64_t)hash_count_perturb);
   fprintf(stderr, "Percentage of perturb loops: %" PRId64 "%%\r\n",
           (int64_t)(hash_count_perturb * 100 / hash_count_lookup));
-#endif  // ifdef HT_DEBUG
+#endif
 }
 
 /// Add (empty) item for key `key` to hashtable `ht`.
@@ -287,7 +287,7 @@ static void hash_may_resize(hashtab_T *ht, size_t minitems)
   if (ht->ht_filled >= ht->ht_mask + 1) {
     emsg("hash_may_resize(): table completely filled");
   }
-#endif  // ifdef HT_DEBUG
+#endif
 
   size_t minsize;
   const size_t oldsize = ht->ht_mask + 1;
diff --git a/src/nvim/help.c b/src/nvim/help.c
index 92807039b3..f1ca249d5d 100644
--- a/src/nvim/help.c
+++ b/src/nvim/help.c
@@ -171,9 +171,9 @@ void ex_help(exarg_T *eap)
       // set b_p_ro flag).
       // Set the alternate file to the previously edited file.
       alt_fnum = curbuf->b_fnum;
-      (void)do_ecmd(0, NULL, NULL, NULL, ECMD_LASTL,
-                    ECMD_HIDE + ECMD_SET_HELP,
-                    NULL);  // buffer is still open, don't store info
+      do_ecmd(0, NULL, NULL, NULL, ECMD_LASTL,
+              ECMD_HIDE + ECMD_SET_HELP,
+              NULL);  // buffer is still open, don't store info
 
       if ((cmdmod.cmod_flags & CMOD_KEEPALT) == 0) {
         curwin->w_alt_fnum = alt_fnum;
@@ -251,7 +251,7 @@ char *check_help_lang(char *arg)
 /// @param wrong_case  no matching case
 ///
 /// @return  a heuristic indicating how well the given string matches.
-int help_heuristic(char *matched_string, int offset, int wrong_case)
+int help_heuristic(char *matched_string, int offset, bool wrong_case)
   FUNC_ATTR_PURE
 {
   int num_letters = 0;
@@ -618,7 +618,7 @@ void prepare_help_buffer(void)
   if (strcmp(curbuf->b_p_isk, p) != 0) {
     set_string_option_direct(kOptIskeyword, p, OPT_FREE|OPT_LOCAL, 0);
     check_buf_options(curbuf);
-    (void)buf_init_chartab(curbuf, false);
+    buf_init_chartab(curbuf, false);
   }
 
   // Don't use the global foldmethod.
diff --git a/src/nvim/highlight_group.c b/src/nvim/highlight_group.c
index 1364d9373c..7c89c9974d 100644
--- a/src/nvim/highlight_group.c
+++ b/src/nvim/highlight_group.c
@@ -979,16 +979,12 @@ void do_highlight(const char *line, const bool forceit, const bool init)
   // Handle ":highlight link {from} {to}" command.
   if (dolink) {
     const char *from_start = linep;
-    const char *from_end;
-    const char *to_start;
-    const char *to_end;
-    int from_id;
     int to_id;
     HlGroup *hlgroup = NULL;
 
-    from_end = skiptowhite(from_start);
-    to_start = skipwhite(from_end);
-    to_end = skiptowhite(to_start);
+    const char *from_end = skiptowhite(from_start);
+    const char *to_start = skipwhite(from_end);
+    const char *to_end = skiptowhite(to_start);
 
     if (ends_excmd((uint8_t)(*from_start))
         || ends_excmd((uint8_t)(*to_start))) {
@@ -1002,7 +998,7 @@ void do_highlight(const char *line, const bool forceit, const bool init)
       return;
     }
 
-    from_id = syn_check_group(from_start, (size_t)(from_end - from_start));
+    int from_id = syn_check_group(from_start, (size_t)(from_end - from_start));
     if (strncmp(to_start, "NONE", 4) == 0) {
       to_id = 0;
     } else {
@@ -1558,7 +1554,7 @@ static void highlight_list_one(const int id)
                             sgp->sg_blend + 1, NULL, "blend");
 
   if (sgp->sg_link && !got_int) {
-    (void)syn_list_header(didh, 0, id, true);
+    syn_list_header(didh, 0, id, true);
     didh = true;
     msg_puts_attr("links to", HL_ATTR(HLF_D));
     msg_putchar(' ');
@@ -1688,7 +1684,7 @@ static bool highlight_list_arg(const int id, bool didh, const int type, int iarg
     }
   }
 
-  (void)syn_list_header(didh, vim_strsize(ts) + (int)strlen(name) + 1, id, false);
+  syn_list_header(didh, vim_strsize(ts) + (int)strlen(name) + 1, id, false);
   didh = true;
   if (!got_int) {
     if (*name != NUL) {
@@ -2076,7 +2072,6 @@ int syn_get_final_id(int hl_id)
 
 bool syn_ns_get_final_id(int *ns_id, int *hl_idp)
 {
-  int count;
   int hl_id = *hl_idp;
   bool used = false;
 
@@ -2087,7 +2082,7 @@ bool syn_ns_get_final_id(int *ns_id, int *hl_idp)
 
   // Follow links until there is no more.
   // Look out for loops!  Break after 100 links.
-  for (count = 100; --count >= 0;) {
+  for (int count = 100; --count >= 0;) {
     HlGroup *sgp = &hl_table[hl_id - 1];  // index is ID minus one
 
     // TODO(bfredl): when using "tmp" attribute (no link) the function might be
diff --git a/src/nvim/indent.c b/src/nvim/indent.c
index 051ff8643d..802bffdbaf 100644
--- a/src/nvim/indent.c
+++ b/src/nvim/indent.c
@@ -888,7 +888,7 @@ int get_breakindent_win(win_T *wp, char *line)
 // non-blank in the line.
 // When extra == 1: Return true if the cursor is before the first non-blank in
 // the line.
-int inindent(int extra)
+bool inindent(int extra)
 {
   char *ptr;
   colnr_T col;
@@ -1340,7 +1340,7 @@ static int lisp_match(char *p)
   char *word = *curbuf->b_p_lw != NUL ? curbuf->b_p_lw : p_lispwords;
 
   while (*word != NUL) {
-    (void)copy_option_part(&word, buf, sizeof(buf), ",");
+    copy_option_part(&word, buf, sizeof(buf), ",");
     int len = (int)strlen(buf);
 
     if ((strncmp(buf, p, (size_t)len) == 0) && ascii_iswhite_or_nul(p[len])) {
diff --git a/src/nvim/input.c b/src/nvim/input.c
index 2dfb67acc5..b5080c87a0 100644
--- a/src/nvim/input.c
+++ b/src/nvim/input.c
@@ -158,7 +158,7 @@ int get_keystroke(MultiQueue *events)
 /// When "mouse_used" is not NULL allow using the mouse.
 ///
 /// @param colon  allow colon to abort
-int get_number(int colon, int *mouse_used)
+int get_number(int colon, bool *mouse_used)
 {
   int n = 0;
   int typed = 0;
@@ -219,7 +219,7 @@ int get_number(int colon, int *mouse_used)
 ///
 /// When "mouse_used" is not NULL allow using the mouse and in that case return
 /// the line number.
-int prompt_for_number(int *mouse_used)
+int prompt_for_number(bool *mouse_used)
 {
   // When using ":silent" assume that <CR> was entered.
   if (mouse_used != NULL) {
diff --git a/src/nvim/insexpand.c b/src/nvim/insexpand.c
index 44229c622b..6162371062 100644
--- a/src/nvim/insexpand.c
+++ b/src/nvim/insexpand.c
@@ -919,13 +919,11 @@ static bool ins_compl_equal(compl_T *match, char *str, size_t len)
 /// Reduce the longest common string for match "match".
 static void ins_compl_longest_match(compl_T *match)
 {
-  int had_match;
-
   if (compl_leader == NULL) {
     // First match, use it as a whole.
     compl_leader = xstrdup(match->cp_str);
 
-    had_match = (curwin->w_cursor.col > compl_col);
+    bool had_match = (curwin->w_cursor.col > compl_col);
     ins_compl_delete();
     ins_bytes(compl_leader + get_compl_len());
     ins_redraw(false);
@@ -959,7 +957,7 @@ static void ins_compl_longest_match(compl_T *match)
   if (*p != NUL) {
     // Leader was shortened, need to change the inserted text.
     *p = NUL;
-    had_match = (curwin->w_cursor.col > compl_col);
+    bool had_match = (curwin->w_cursor.col > compl_col);
     ins_compl_delete();
     ins_bytes(compl_leader + get_compl_len());
     ins_redraw(false);
@@ -1321,7 +1319,7 @@ void compl_set_info(int pum_idx)
 ///
 /// @param flags      DICT_FIRST and/or DICT_EXACT
 /// @param thesaurus  Thesaurus completion
-static void ins_compl_dictionaries(char *dict_start, char *pat, int flags, int thesaurus)
+static void ins_compl_dictionaries(char *dict_start, char *pat, int flags, bool thesaurus)
 {
   char *dict = dict_start;
   char *ptr;
@@ -1464,8 +1462,8 @@ static int thesaurus_add_words_in_line(char *fname, char **buf_arg, int dir, con
 
 /// Process "count" dictionary/thesaurus "files" and add the text matching
 /// "regmatch".
-static void ins_compl_files(int count, char **files, int thesaurus, int flags, regmatch_T *regmatch,
-                            char *buf, Direction *dir)
+static void ins_compl_files(int count, char **files, bool thesaurus, int flags,
+                            regmatch_T *regmatch, char *buf, Direction *dir)
   FUNC_ATTR_NONNULL_ARG(2, 7)
 {
   for (int i = 0; i < count && !got_int && !compl_interrupted; i++) {
@@ -1474,7 +1472,7 @@ static void ins_compl_files(int count, char **files, int thesaurus, int flags, r
       msg_hist_off = true;  // reset in msg_trunc()
       vim_snprintf(IObuff, IOSIZE,
                    _("Scanning dictionary: %s"), files[i]);
-      (void)msg_trunc(IObuff, true, HL_ATTR(HLF_R));
+      msg_trunc(IObuff, true, HL_ATTR(HLF_R));
     }
 
     if (fp == NULL) {
@@ -2954,7 +2952,7 @@ static int process_next_cpt_value(ins_compl_next_state_T *st, int *compl_type_ar
                    : st->ins_buf->b_sfname == NULL
                    ? st->ins_buf->b_fname
                    : st->ins_buf->b_sfname);
-      (void)msg_trunc(IObuff, true, HL_ATTR(HLF_R));
+      msg_trunc(IObuff, true, HL_ATTR(HLF_R));
     }
   } else if (*st->e_cpt == NUL) {
     status = INS_COMPL_CPT_END;
@@ -2982,12 +2980,12 @@ static int process_next_cpt_value(ins_compl_next_state_T *st, int *compl_type_ar
       if (!shortmess(SHM_COMPLETIONSCAN)) {
         msg_hist_off = true;  // reset in msg_trunc()
         vim_snprintf(IObuff, IOSIZE, "%s", _("Scanning tags."));
-        (void)msg_trunc(IObuff, true, HL_ATTR(HLF_R));
+        msg_trunc(IObuff, true, HL_ATTR(HLF_R));
       }
     }
 
     // in any case e_cpt is advanced to the next entry
-    (void)copy_option_part(&st->e_cpt, IObuff, IOSIZE, ",");
+    copy_option_part(&st->e_cpt, IObuff, IOSIZE, ",");
 
     st->found_all = true;
     if (compl_type == -1) {
@@ -3814,8 +3812,8 @@ void ins_compl_check_keys(int frequency, bool in_compl_func)
     if (vim_is_ctrl_x_key(c) && c != Ctrl_X && c != Ctrl_R) {
       c = safe_vgetc();         // Eat the character
       compl_shows_dir = ins_compl_key2dir(c);
-      (void)ins_compl_next(false, ins_compl_key2count(c),
-                           c != K_UP && c != K_DOWN, in_compl_func);
+      ins_compl_next(false, ins_compl_key2count(c),
+                     c != K_UP && c != K_DOWN, in_compl_func);
     } else {
       // Need to get the character to have KeyTyped set.  We'll put it
       // back with vungetc() below.  But skip K_IGNORE.
@@ -3835,7 +3833,7 @@ void ins_compl_check_keys(int frequency, bool in_compl_func)
     int todo = compl_pending > 0 ? compl_pending : -compl_pending;
 
     compl_pending = 0;
-    (void)ins_compl_next(false, todo, true, in_compl_func);
+    ins_compl_next(false, todo, true, in_compl_func);
   }
 }
 
@@ -3937,8 +3935,8 @@ static int get_normal_compl_info(char *line, int startcol, colnr_T curs_col)
       prefix = "";
     }
     STRCPY(compl_pattern, prefix);
-    (void)quote_meta(compl_pattern + strlen(prefix),
-                     line + compl_col, compl_length);
+    quote_meta(compl_pattern + strlen(prefix),
+               line + compl_col, compl_length);
   } else if (--startcol < 0
              || !vim_iswordp(mb_prevptr(line, line + startcol + 1))) {
     // Match any word of at least two chars
@@ -3965,12 +3963,12 @@ static int get_normal_compl_info(char *line, int startcol, colnr_T curs_col)
       // xmalloc(7) is enough  -- Acevedo
       compl_pattern = xmalloc(7);
       STRCPY(compl_pattern, "\\<");
-      (void)quote_meta(compl_pattern + 2, line + compl_col, 1);
+      quote_meta(compl_pattern + 2, line + compl_col, 1);
       STRCAT(compl_pattern, "\\k");
     } else {
       compl_pattern = xmalloc(quote_meta(NULL, line + compl_col, compl_length) + 2);
       STRCPY(compl_pattern, "\\<");
-      (void)quote_meta(compl_pattern + 2, line + compl_col, compl_length);
+      quote_meta(compl_pattern + 2, line + compl_col, compl_length);
     }
   }
 
@@ -4449,7 +4447,7 @@ int ins_complete(int c, bool enable_pum)
   // Eat the ESC that vgetc() returns after a CTRL-C to avoid leaving Insert
   // mode.
   if (got_int && !global_busy) {
-    (void)vgetc();
+    vgetc();
     got_int = false;
   }
 
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 6289ea3193..116e8136cc 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -2172,7 +2172,7 @@ int nlua_do_ucmd(ucmd_T *cmd, exarg_T *eap, bool preview)
   // every possible modifier (with room to spare). If the list of possible
   // modifiers grows this may need to be updated.
   char buf[200] = { 0 };
-  (void)uc_mods(buf, &cmdmod, false);
+  uc_mods(buf, &cmdmod, false);
   lua_pushstring(lstate, buf);
   lua_setfield(lstate, -2, "mods");
 
diff --git a/src/nvim/main.c b/src/nvim/main.c
index f01b6ecc8d..264593ffe8 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -615,7 +615,7 @@ int main(int argc, char **argv)
 
   // WORKAROUND(mhi): #3023
   if (cb_flags & CB_UNNAMEDMASK) {
-    (void)eval_has_provider("clipboard");
+    eval_has_provider("clipboard");
   }
 
   if (params.luaf != NULL) {
@@ -1013,7 +1013,7 @@ static void command_line_scan(mparm_T *parmp)
   char **argv = parmp->argv;
   int argv_idx;                         // index in argv[n][]
   bool had_minmin = false;              // found "--" argument
-  int want_argument;                    // option argument with argument
+  bool want_argument;                   // option argument with argument
   int n;
 
   argc--;
@@ -1581,7 +1581,7 @@ static void read_stdin(void)
   bool save_msg_didany = msg_didany;
   set_buflisted(true);
   // Create memfile and read from stdin.
-  (void)open_buffer(true, NULL, 0);
+  open_buffer(true, NULL, 0);
   if (buf_is_empty(curbuf) && curbuf->b_next != NULL) {
     // stdin was empty, go to buffer 2 (e.g. "echo file1 | xargs nvim"). #8561
     do_cmdline_cmd("silent! bnext");
@@ -1703,7 +1703,7 @@ static void create_windows(mparm_T *parmp)
         set_buflisted(true);
 
         // create memfile, read file
-        (void)open_buffer(false, NULL, 0);
+        open_buffer(false, NULL, 0);
 
         if (swap_exists_action == SEA_QUIT) {
           if (got_int || only_one_window()) {
@@ -1725,7 +1725,7 @@ static void create_windows(mparm_T *parmp)
       }
       os_breakcheck();
       if (got_int) {
-        (void)vgetc();          // only break the file loading, not the rest
+        vgetc();          // only break the file loading, not the rest
         break;
       }
     }
@@ -1804,9 +1804,9 @@ static void edit_buffers(mparm_T *parmp, char *cwd)
       // Edit file from arg list, if there is one.  When "Quit" selected
       // at the ATTENTION prompt close the window.
       swap_exists_did_quit = false;
-      (void)do_ecmd(0, arg_idx < GARGCOUNT
-                    ? alist_name(&GARGLIST[arg_idx])
-                    : NULL, NULL, NULL, ECMD_LASTL, ECMD_HIDE, curwin);
+      do_ecmd(0, arg_idx < GARGCOUNT
+              ? alist_name(&GARGLIST[arg_idx])
+              : NULL, NULL, NULL, ECMD_LASTL, ECMD_HIDE, curwin);
       if (swap_exists_did_quit) {
         // abort or quit selected
         if (got_int || only_one_window()) {
@@ -1825,7 +1825,7 @@ static void edit_buffers(mparm_T *parmp, char *cwd)
     }
     os_breakcheck();
     if (got_int) {
-      (void)vgetc();            // only break the file loading, not the rest
+      vgetc();            // only break the file loading, not the rest
       break;
     }
   }
@@ -1957,7 +1957,7 @@ static void do_system_initialization(void)
 
 #ifdef SYS_VIMRC_FILE
   // Get system wide defaults, if the file name is defined.
-  (void)do_source(SYS_VIMRC_FILE, false, DOSO_NONE, NULL);
+  do_source(SYS_VIMRC_FILE, false, DOSO_NONE, NULL);
 #endif
 }
 
diff --git a/src/nvim/mapping.c b/src/nvim/mapping.c
index 63604352cf..58fce92fb0 100644
--- a/src/nvim/mapping.c
+++ b/src/nvim/mapping.c
@@ -1528,7 +1528,6 @@ bool check_abbr(int c, char *ptr, int col, int mincol)
                             : (mp = mp->m_next)) {
       int qlen = mp->m_keylen;
       char *q = mp->m_keys;
-      int match;
 
       if (strchr(mp->m_keys, K_SPECIAL) != NULL) {
         // Might have K_SPECIAL escaped mp->m_keys.
@@ -1537,9 +1536,9 @@ bool check_abbr(int c, char *ptr, int col, int mincol)
         qlen = (int)strlen(q);
       }
       // find entries with right mode and keys
-      match = (mp->m_mode & State)
-              && qlen == len
-              && !strncmp(q, ptr, (size_t)len);
+      int match = (mp->m_mode & State)
+                  && qlen == len
+                  && !strncmp(q, ptr, (size_t)len);
       if (q != mp->m_keys) {
         xfree(q);
       }
@@ -1587,7 +1586,7 @@ bool check_abbr(int c, char *ptr, int col, int mincol)
         }
         tb[j] = NUL;
         // insert the last typed char
-        (void)ins_typebuf((char *)tb, 1, 0, true, mp->m_silent);
+        ins_typebuf((char *)tb, 1, 0, true, mp->m_silent);
       }
 
       // copy values here, calling eval_map_expr() may make "mp" invalid!
@@ -1603,7 +1602,7 @@ bool check_abbr(int c, char *ptr, int col, int mincol)
       }
       if (s != NULL) {
         // insert the to string
-        (void)ins_typebuf(s, noremap, 0, true, silent);
+        ins_typebuf(s, noremap, 0, true, silent);
         // no abbrev. for these chars
         typebuf.tb_no_abbr_cnt += (int)strlen(s) + j + 1;
         if (expr) {
@@ -1615,7 +1614,7 @@ bool check_abbr(int c, char *ptr, int col, int mincol)
       tb[1] = NUL;
       len = clen;  // Delete characters instead of bytes
       while (len-- > 0) {  // delete the from string
-        (void)ins_typebuf((char *)tb, 1, 0, true, silent);
+        ins_typebuf((char *)tb, 1, 0, true, silent);
       }
       return true;
     }
@@ -2177,8 +2176,8 @@ static void get_maparg(typval_T *argvars, typval_T *rettv, int exact)
   if (did_simplify) {
     // When the lhs is being simplified the not-simplified keys are
     // preferred for printing, like in do_map().
-    (void)replace_termcodes(keys, strlen(keys), &alt_keys_buf, 0,
-                            flags | REPTERM_NO_SIMPLIFY, NULL, p_cpo);
+    replace_termcodes(keys, strlen(keys), &alt_keys_buf, 0,
+                      flags | REPTERM_NO_SIMPLIFY, NULL, p_cpo);
     rhs = check_map(alt_keys_buf, mode, exact, false, abbr, &mp, &buffer_local, &rhs_lua);
   }
 
@@ -2399,8 +2398,8 @@ void f_maplist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
         bool did_simplify = false;
 
         char *lhs = str2special_save(mp->m_keys, true, false);
-        (void)replace_termcodes(lhs, strlen(lhs), &keys_buf, 0, flags, &did_simplify,
-                                p_cpo);
+        replace_termcodes(lhs, strlen(lhs), &keys_buf, 0, flags, &did_simplify,
+                          p_cpo);
         xfree(lhs);
 
         Dictionary dict = mapblock_fill_dict(mp,
diff --git a/src/nvim/mark.c b/src/nvim/mark.c
index 69042a6034..075c371024 100644
--- a/src/nvim/mark.c
+++ b/src/nvim/mark.c
@@ -929,8 +929,8 @@ void ex_delmarks(exarg_T *eap)
     // clear specified marks only
     const Timestamp timestamp = os_time();
     for (char *p = eap->arg; *p != NUL; p++) {
-      int lower = ASCII_ISLOWER(*p);
-      int digit = ascii_isdigit(*p);
+      bool lower = ASCII_ISLOWER(*p);
+      bool digit = ascii_isdigit(*p);
       if (lower || digit || ASCII_ISUPPER(*p)) {
         if (p[1] == '-') {
           // clear range of marks
diff --git a/src/nvim/mbyte.c b/src/nvim/mbyte.c
index b788d7aa6f..75e38c59f3 100644
--- a/src/nvim/mbyte.c
+++ b/src/nvim/mbyte.c
@@ -2251,7 +2251,7 @@ void *my_iconv_open(char *to, char *from)
     // stops for no apparent reason after about 8160 characters.
     char *p = tobuf;
     size_t tolen = ICONV_TESTLEN;
-    (void)iconv(fd, NULL, NULL, &p, &tolen);
+    iconv(fd, NULL, NULL, &p, &tolen);
     if (p == NULL) {
       iconv_working = kBroken;
       iconv_close(fd);
diff --git a/src/nvim/memfile.c b/src/nvim/memfile.c
index fc877d08a3..e7b23021dd 100644
--- a/src/nvim/memfile.c
+++ b/src/nvim/memfile.c
@@ -205,7 +205,7 @@ void mf_close_file(buf_T *buf, bool getlines)
   if (getlines) {
     // get all blocks in memory by accessing all lines (clumsy!)
     for (linenr_T lnum = 1; lnum <= buf->b_ml.ml_line_count; lnum++) {
-      (void)ml_get_buf(buf, lnum);
+      ml_get_buf(buf, lnum);
     }
   }
 
@@ -272,7 +272,7 @@ bhdr_T *mf_new(memfile_T *mfp, bool negative, unsigned page_count)
 
   // Init the data to all zero, to avoid reading uninitialized data.
   // This also avoids that the passwd file ends up in the swap file!
-  (void)memset(hp->bh_data, 0, (size_t)mfp->mf_page_size * page_count);
+  memset(hp->bh_data, 0, (size_t)mfp->mf_page_size * page_count);
 
   return hp;
 }
@@ -758,7 +758,7 @@ static bool mf_do_open(memfile_T *mfp, char *fname, int flags)
     return false;
   }
 
-  (void)os_set_cloexec(mfp->mf_fd);
+  os_set_cloexec(mfp->mf_fd);
 
   return true;
 }
diff --git a/src/nvim/memline.c b/src/nvim/memline.c
index 8f6b78d2d5..220e16ad99 100644
--- a/src/nvim/memline.c
+++ b/src/nvim/memline.c
@@ -328,7 +328,7 @@ int ml_open(buf_T *buf)
     b0p->b0_dirty = buf->b_changed ? B0_DIRTY : 0;
     b0p->b0_flags = (char)(get_fileformat(buf) + 1);
     set_b0_fname(b0p, buf);
-    (void)os_get_username(b0p->b0_uname, B0_UNAME_SIZE);
+    os_get_username(b0p->b0_uname, B0_UNAME_SIZE);
     b0p->b0_uname[B0_UNAME_SIZE - 1] = NUL;
     os_get_hostname(b0p->b0_hname, B0_HNAME_SIZE);
     b0p->b0_hname[B0_HNAME_SIZE - 1] = NUL;
@@ -342,7 +342,7 @@ int ml_open(buf_T *buf)
   // is created.
   mf_put(mfp, hp, true, false);
   if (!buf->b_help && !buf->b_spell) {
-    (void)mf_sync(mfp, 0);
+    mf_sync(mfp, 0);
   }
 
   // Fill in root pointer block and write page 1.
@@ -448,7 +448,7 @@ void ml_setname(buf_T *buf)
       emsg(_("E301: Oops, lost the swap file!!!"));
       return;
     }
-    (void)os_set_cloexec(mfp->mf_fd);
+    os_set_cloexec(mfp->mf_fd);
   }
   if (!success) {
     emsg(_("E302: Could not rename swap file"));
@@ -483,7 +483,7 @@ void ml_open_file(buf_T *buf)
   if (buf->b_spell) {
     char *fname = vim_tempname();
     if (fname != NULL) {
-      (void)mf_open_file(mfp, fname);           // consumes fname!
+      mf_open_file(mfp, fname);           // consumes fname!
     }
     buf->b_may_swap = false;
     return;
@@ -527,8 +527,8 @@ void ml_open_file(buf_T *buf)
   if (*p_dir != NUL && mfp->mf_fname == NULL) {
     need_wait_return = true;  // call wait_return() later
     no_wait_return++;
-    (void)semsg(_("E303: Unable to open swap file for \"%s\", recovery impossible"),
-                buf_spname(buf) != NULL ? buf_spname(buf) : buf->b_fname);
+    semsg(_("E303: Unable to open swap file for \"%s\", recovery impossible"),
+          buf_spname(buf) != NULL ? buf_spname(buf) : buf->b_fname);
     no_wait_return--;
   }
 
@@ -792,7 +792,7 @@ void ml_recover(bool checkext)
       i = 1;
     } else {  // several swapfiles found, choose
       // list the names of the swapfiles
-      (void)recover_names(fname, true, NULL, 0, NULL);
+      recover_names(fname, true, NULL, 0, NULL);
       msg_putchar('\n');
       msg_puts(_("Enter number of swap file to use (0 to quit): "));
       i = get_number(false, NULL);
@@ -801,7 +801,7 @@ void ml_recover(bool checkext)
       }
     }
     // get the swapfile name that will be used
-    (void)recover_names(fname, false, NULL, i, &fname_used);
+    recover_names(fname, false, NULL, i, &fname_used);
   }
   if (fname_used == NULL) {
     goto theend;  // user chose invalid number.
@@ -1289,7 +1289,7 @@ int recover_names(char *fname, bool do_list, list_T *ret_list, int nr, char **fn
     // Isolate a directory name from *dirp and put it in dir_name (we know
     // it is large enough, so use 31000 for length).
     // Advance dirp to next directory name.
-    (void)copy_option_part(&dirp, dir_name, 31000, ",");
+    copy_option_part(&dirp, dir_name, 31000, ",");
 
     if (dir_name[0] == '.' && dir_name[1] == NUL) {     // check current dir
       if (fname == NULL) {
@@ -1400,7 +1400,7 @@ int recover_names(char *fname, bool do_list, list_T *ret_list, int nr, char **fn
           msg_puts(".    ");
           msg_puts(path_tail(files[i]));
           msg_putchar('\n');
-          (void)swapfile_info(files[i]);
+          swapfile_info(files[i]);
         }
       } else {
         msg_puts(_("      -- none --\n"));
@@ -1639,7 +1639,7 @@ static bool swapfile_unchanged(char *fname)
   return ret;
 }
 
-static int recov_file_names(char **names, char *path, int prepend_dot)
+static int recov_file_names(char **names, char *path, bool prepend_dot)
   FUNC_ATTR_NONNULL_ALL
 {
   int num_names = 0;
@@ -1688,7 +1688,7 @@ void ml_sync_all(int check_file, int check_char, bool do_fsync)
     }
     ml_flush_line(buf);                     // flush buffered line
                                             // flush locked block
-    (void)ml_find_line(buf, 0, ML_FLUSH);
+    ml_find_line(buf, 0, ML_FLUSH);
     if (bufIsChanged(buf) && check_file && mf_need_trans(buf->b_ml.ml_mfp)
         && buf->b_ffname != NULL) {
       // If the original file does not exist anymore or has been changed
@@ -1704,8 +1704,8 @@ void ml_sync_all(int check_file, int check_char, bool do_fsync)
       }
     }
     if (buf->b_ml.ml_mfp->mf_dirty == MF_DIRTY_YES) {
-      (void)mf_sync(buf->b_ml.ml_mfp, (check_char ? MFS_STOP : 0)
-                    | (do_fsync && bufIsChanged(buf) ? MFS_FLUSH : 0));
+      mf_sync(buf->b_ml.ml_mfp, (check_char ? MFS_STOP : 0)
+              | (do_fsync && bufIsChanged(buf) ? MFS_FLUSH : 0));
       if (check_char && os_char_avail()) {      // character available now
         break;
       }
@@ -1721,7 +1721,7 @@ void ml_sync_all(int check_file, int check_char, bool do_fsync)
 /// changed or deleted.
 ///
 /// @param message  if true, the success of preserving is reported.
-void ml_preserve(buf_T *buf, int message, bool do_fsync)
+void ml_preserve(buf_T *buf, bool message, bool do_fsync)
 {
   memfile_T *mfp = buf->b_ml.ml_mfp;
   int got_int_save = got_int;
@@ -1738,7 +1738,7 @@ void ml_preserve(buf_T *buf, int message, bool do_fsync)
   got_int = false;
 
   ml_flush_line(buf);                               // flush buffered line
-  (void)ml_find_line(buf, 0, ML_FLUSH);   // flush locked block
+  ml_find_line(buf, 0, ML_FLUSH);   // flush locked block
   int status = mf_sync(mfp, MFS_ALL | (do_fsync ? MFS_FLUSH : 0));
 
   // stack is invalid after mf_sync(.., MFS_ALL)
@@ -1765,7 +1765,7 @@ void ml_preserve(buf_T *buf, int message, bool do_fsync)
       CHECK(buf->b_ml.ml_locked_low != lnum, "low != lnum");
       lnum = buf->b_ml.ml_locked_high + 1;
     }
-    (void)ml_find_line(buf, 0, ML_FLUSH);  // flush locked block
+    ml_find_line(buf, 0, ML_FLUSH);  // flush locked block
     // sync the updated pointer blocks
     if (mf_sync(mfp, MFS_ALL | (do_fsync ? MFS_FLUSH : 0)) == FAIL) {
       status = FAIL;
@@ -1986,7 +1986,8 @@ int ml_append_buf(buf_T *buf, linenr_T lnum, char *line, colnr_T len, bool newfi
 /// @param len  length of line, including NUL, or 0
 /// @param newfile  flag, see above
 /// @param mark  mark the new line
-static int ml_append_int(buf_T *buf, linenr_T lnum, char *line, colnr_T len, bool newfile, int mark)
+static int ml_append_int(buf_T *buf, linenr_T lnum, char *line, colnr_T len, bool newfile,
+                         bool mark)
 {
   // lnum out of range
   if (lnum > buf->b_ml.ml_line_count || buf->b_ml.ml_mfp == NULL) {
@@ -2239,7 +2240,7 @@ static int ml_append_int(buf_T *buf, linenr_T lnum, char *line, colnr_T len, boo
     // pointer blocks is done below
     int lineadd = buf->b_ml.ml_locked_lineadd;
     buf->b_ml.ml_locked_lineadd = 0;
-    (void)ml_find_line(buf, 0, ML_FLUSH);  // flush data block
+    ml_find_line(buf, 0, ML_FLUSH);  // flush data block
 
     // update pointer blocks for the new data block
     for (stack_idx = buf->b_ml.ml_stack_top - 1; stack_idx >= 0; stack_idx--) {
@@ -2286,8 +2287,7 @@ static int ml_append_int(buf_T *buf, linenr_T lnum, char *line, colnr_T len, boo
           // fix line count for rest of blocks in the stack
           ml_lineadd(buf, lineadd);
           // fix stack itself
-          buf->b_ml.ml_stack[buf->b_ml.ml_stack_top].ip_high +=
-            lineadd;
+          buf->b_ml.ml_stack[buf->b_ml.ml_stack_top].ip_high += lineadd;
           (buf->b_ml.ml_stack_top)++;
         }
 
@@ -2785,9 +2785,9 @@ static void ml_flush_line(buf_T *buf)
         // that has only one line.
         // Don't forget to copy the mark!
         // How about handling errors???
-        (void)ml_append_int(buf, lnum, new_line, new_len, false,
-                            (int)(dp->db_index[idx] & DB_MARKED));
-        (void)ml_delete_int(buf, lnum, false);
+        ml_append_int(buf, lnum, new_line, new_len, false,
+                      (int)(dp->db_index[idx] & DB_MARKED));
+        ml_delete_int(buf, lnum, false);
       }
     }
     xfree(new_line);
@@ -3205,7 +3205,7 @@ static void attention_message(buf_T *buf, char *fname)
   assert(buf->b_fname != NULL);
 
   no_wait_return++;
-  (void)emsg(_("E325: ATTENTION"));
+  emsg(_("E325: ATTENTION"));
   msg_puts(_("\nFound a swap file by the name \""));
   msg_home_replace(fname);
   msg_puts("\"\n");
@@ -3308,7 +3308,7 @@ static char *findswapname(buf_T *buf, char **dirp, char *old_fname, bool *found_
   // First allocate some memory to put the directory name in.
   const size_t dir_len = strlen(*dirp) + 1;
   char *dir_name = xmalloc(dir_len);
-  (void)copy_option_part(dirp, dir_name, dir_len, ",");
+  copy_option_part(dirp, dir_name, dir_len, ",");
 
   // We try different swapfile names until we find one that does not exist yet.
   char *fname = makeswapname(buf_fname, buf->b_ffname, buf, dir_name);
diff --git a/src/nvim/menu.c b/src/nvim/menu.c
index c4486222a5..b61c28a4df 100644
--- a/src/nvim/menu.c
+++ b/src/nvim/menu.c
@@ -69,7 +69,7 @@ void ex_menu(exarg_T *eap)
   char *map_to;            // command mapped to the menu entry
   int noremap;
   bool silent = false;
-  int unmenu;
+  bool unmenu;
   char *map_buf;
   char *p;
   int i;
@@ -868,7 +868,7 @@ char *set_context_in_menu_cmd(expand_T *xp, const char *cmd, char *arg, bool for
   char *after_dot;
   char *p;
   char *path_name = NULL;
-  int unmenu;
+  bool unmenu;
   vimmenu_T *menu;
 
   xp->xp_context = EXPAND_UNSUCCESSFUL;
@@ -1132,7 +1132,7 @@ static bool menu_namecmp(const char *const name, const char *const mname)
 ///                     to whether the command is a "nore" command.
 /// @param[out] unmenu  If not NULL, the flag it points to is set according
 ///                     to whether the command is an "unmenu" command.
-int get_menu_cmd_modes(const char *cmd, bool forceit, int *noremap, int *unmenu)
+int get_menu_cmd_modes(const char *cmd, bool forceit, int *noremap, bool *unmenu)
 {
   int modes;
 
diff --git a/src/nvim/message.c b/src/nvim/message.c
index 2c0e8064fb..7527349e5e 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -228,7 +228,7 @@ int verb_msg(const char *s)
 /// When terminal not initialized (yet) printf("%s", ..) is used.
 ///
 /// @return  true if wait_return() not called
-int msg(const char *s, const int attr)
+bool msg(const char *s, const int attr)
   FUNC_ATTR_NONNULL_ARG(1)
 {
   return msg_attr_keep(s, attr, false, false);
@@ -289,7 +289,6 @@ bool msg_attr_keep(const char *s, int attr, bool keep, bool multiline)
   FUNC_ATTR_NONNULL_ALL
 {
   static int entered = 0;
-  char *buf = NULL;
 
   if (keep && multiline) {
     // Not implemented. 'multiline' is only used by nvim-added messages,
@@ -328,7 +327,7 @@ bool msg_attr_keep(const char *s, int attr, bool keep, bool multiline)
 
   // Truncate the message if needed.
   msg_start();
-  buf = msg_strtrunc(s, false);
+  char *buf = msg_strtrunc(s, false);
   if (buf != NULL) {
     s = buf;
   }
@@ -342,7 +341,7 @@ bool msg_attr_keep(const char *s, int attr, bool keep, bool multiline)
   if (need_clear) {
     msg_clr_eos();
   }
-  int retval = msg_end();
+  bool retval = msg_end();
 
   if (keep && retval && vim_strsize(s) < (Rows - cmdline_row - 1) * Columns + sc_col) {
     set_keep_msg(s, 0);
@@ -461,7 +460,7 @@ void trunc_string(const char *s, char *buf, int room_in, int buflen)
     }
   } else if (e + 3 < buflen) {
     // set the middle and copy the last part
-    memmove(buf + e, "...", (size_t)3);
+    memmove(buf + e, "...", 3);
     len = (int)strlen(s + i) + 1;
     if (len >= buflen - e - 3) {
       len = buflen - e - 3 - 1;
@@ -840,7 +839,7 @@ void siemsg(const char *s, ...)
 
   va_list ap;
   va_start(ap, s);
-  (void)semsgv(s, ap);
+  semsgv(s, ap);
   va_end(ap);
 #ifdef ABORT_ON_INTERNAL_ERROR
   msg_putchar('\n');  // avoid overwriting the error message
@@ -858,7 +857,7 @@ void internal_error(const char *where)
 static void msg_semsg_event(void **argv)
 {
   char *s = argv[0];
-  (void)emsg(s);
+  emsg(s);
   xfree(s);
 }
 
@@ -877,7 +876,7 @@ void msg_schedule_semsg(const char *const fmt, ...)
 static void msg_semsg_multiline_event(void **argv)
 {
   char *s = argv[0];
-  (void)emsg_multiline(s, true);
+  emsg_multiline(s, true);
   xfree(s);
 }
 
@@ -905,7 +904,7 @@ char *msg_trunc(char *s, bool force, int attr)
   char *ts = msg_may_trunc(force, s);
 
   msg_hist_off = true;
-  int n = msg(ts, attr);
+  bool n = msg(ts, attr);
   msg_hist_off = false;
 
   if (n) {
@@ -970,7 +969,7 @@ static void add_msg_hist_multiattr(const char *s, int len, int attr, bool multil
 
   // Don't let the message history get too big
   while (msg_hist_len > MAX_MSG_HIST_LEN) {
-    (void)delete_first_msg();
+    delete_first_msg();
   }
 
   // allocate an entry and add the message at the end of the history
@@ -1035,7 +1034,7 @@ void ex_messages(exarg_T *eap)
     int keep = eap->addr_count == 0 ? 0 : eap->line2;
 
     while (msg_hist_len > keep) {
-      (void)delete_first_msg();
+      delete_first_msg();
     }
     return;
   }
@@ -1250,7 +1249,7 @@ void wait_return(int redraw)
     // Avoid that the mouse-up event causes visual mode to start.
     if (c == K_LEFTMOUSE || c == K_MIDDLEMOUSE || c == K_RIGHTMOUSE
         || c == K_X1MOUSE || c == K_X2MOUSE) {
-      (void)jump_to_mouse(MOUSE_SETPOS, NULL, 0);
+      jump_to_mouse(MOUSE_SETPOS, NULL, 0);
     } else if (vim_strchr("\r\n ", c) == NULL && c != Ctrl_C) {
       // Put the character back in the typeahead buffer.  Don't use the
       // stuff buffer, because lmaps wouldn't work.
@@ -1797,7 +1796,7 @@ void str2specialbuf(const char *sp, char *buf, size_t len)
 }
 
 /// print line for :print or :list command
-void msg_prt_line(const char *s, int list)
+void msg_prt_line(const char *s, bool list)
 {
   int c;
   int col = 0;
@@ -2523,7 +2522,7 @@ void sb_text_end_cmdline(void)
 /// Clear any text remembered for scrolling back.
 /// When "all" is false keep the last line.
 /// Called when redrawing the screen.
-void clear_sb_text(int all)
+void clear_sb_text(bool all)
 {
   msgchunk_T *mp;
   msgchunk_T **lastp;
@@ -2827,7 +2826,7 @@ static bool do_more_prompt(int typed_char)
             grid_fill(&msg_grid_adj, 0, 1, 0, Columns, ' ', ' ',
                       HL_ATTR(HLF_MSG));
             // display line at top
-            (void)disp_sb_line(0, mp);
+            disp_sb_line(0, mp);
           } else {
             // redisplay all lines
             // TODO(bfredl): this case is not optimized (though only concerns
@@ -2899,7 +2898,7 @@ static bool do_more_prompt(int typed_char)
   return retval;
 }
 
-void msg_moremsg(int full)
+void msg_moremsg(bool full)
 {
   int attr = hl_combine_attr(HL_ATTR(HLF_MSG), HL_ATTR(HLF_M));
   grid_line_start(&msg_grid_adj, Rows - 1);
@@ -2991,7 +2990,7 @@ void msg_clr_cmdline(void)
 /// call wait_return() if the message does not fit in the available space
 ///
 /// @return  true if wait_return() not called.
-int msg_end(void)
+bool msg_end(void)
 {
   // If the string is larger than the window,
   // or the ruler option is set and we run into it,
diff --git a/src/nvim/mouse.c b/src/nvim/mouse.c
index a026859a7e..7405c8c38b 100644
--- a/src/nvim/mouse.c
+++ b/src/nvim/mouse.c
@@ -187,7 +187,7 @@ static void call_click_def_func(StlClickDefinition *click_defs, int col, int whi
     }
   };
   typval_T rettv;
-  (void)call_vim_function(click_defs[col].func, ARRAY_SIZE(argv), argv, &rettv);
+  call_vim_function(click_defs[col].func, ARRAY_SIZE(argv), argv, &rettv);
   tv_clear(&rettv);
   // Make sure next click does not register as drag when callback absorbs the release event.
   got_click = false;
@@ -1010,7 +1010,7 @@ void do_mousescroll(cmdarg_T *cap)
     // Vertical scrolling
     if ((State & MODE_NORMAL) && shift_or_ctrl) {
       // whole page up or down
-      (void)onepage(cap->arg ? FORWARD : BACKWARD, 1);
+      onepage(cap->arg ? FORWARD : BACKWARD, 1);
     } else {
       if (shift_or_ctrl) {
         // whole page up or down
@@ -1030,7 +1030,7 @@ void do_mousescroll(cmdarg_T *cap)
     if (leftcol < 0) {
       leftcol = 0;
     }
-    (void)do_mousescroll_horiz(leftcol);
+    do_mousescroll_horiz(leftcol);
   }
 }
 
@@ -1416,7 +1416,7 @@ retnomove:
           break;
         }
         first = false;
-        (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+        hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
         if (curwin->w_topfill < win_get_fill(curwin, curwin->w_topline)) {
           curwin->w_topfill++;
         } else {
@@ -1577,7 +1577,7 @@ void nv_mousescroll(cmdarg_T *cap)
 /// Mouse clicks and drags.
 void nv_mouse(cmdarg_T *cap)
 {
-  (void)do_mouse(cap->oap, cap->cmdchar, BACKWARD, cap->count1, 0);
+  do_mouse(cap->oap, cap->cmdchar, BACKWARD, cap->count1, 0);
 }
 
 /// Compute the position in the buffer line from the posn on the screen in
@@ -1626,7 +1626,7 @@ bool mouse_comp_pos(win_T *win, int *rowp, int *colp, linenr_T *lnump)
       break;            // Position is in this buffer line.
     }
 
-    (void)hasFoldingWin(win, lnum, NULL, &lnum, true, NULL);
+    hasFoldingWin(win, lnum, NULL, &lnum, true, NULL);
 
     if (lnum == win->w_buffer->b_ml.ml_line_count) {
       retval = true;
@@ -1939,7 +1939,7 @@ void f_getmousepos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       winrow = row + 1 + wp->w_winrow_off;  // Adjust by 1 for top border
       wincol = col + 1 + wp->w_wincol_off;  // Adjust by 1 for left border
       if (row >= 0 && row < wp->w_height && col >= 0 && col < wp->w_width) {
-        (void)mouse_comp_pos(wp, &row, &col, &lnum);
+        mouse_comp_pos(wp, &row, &col, &lnum);
         col = vcol2col(wp, lnum, col, &coladd);
         column = col + 1;
       }
diff --git a/src/nvim/move.c b/src/nvim/move.c
index d7bd18f23b..d23b57823e 100644
--- a/src/nvim/move.c
+++ b/src/nvim/move.c
@@ -302,7 +302,7 @@ void update_topline(win_T *wp)
           if (lnum >= wp->w_buffer->b_ml.ml_line_count || n >= halfheight) {
             break;
           }
-          (void)hasFoldingWin(wp, lnum, NULL, &lnum, true, NULL);
+          hasFoldingWin(wp, lnum, NULL, &lnum, true, NULL);
         }
       } else {
         n = wp->w_topline + *so_ptr - wp->w_cursor.lnum;
@@ -319,7 +319,7 @@ void update_topline(win_T *wp)
       }
     } else {
       // Make sure topline is the first line of a fold.
-      (void)hasFoldingWin(wp, wp->w_topline, &wp->w_topline, NULL, true, NULL);
+      hasFoldingWin(wp, wp->w_topline, &wp->w_topline, NULL, true, NULL);
       check_botline = true;
     }
   }
@@ -347,7 +347,7 @@ void update_topline(win_T *wp)
           int n = wp->w_empty_rows;
           loff.lnum = wp->w_cursor.lnum;
           // In a fold go to its last line.
-          (void)hasFoldingWin(wp, loff.lnum, NULL, &loff.lnum, true, NULL);
+          hasFoldingWin(wp, loff.lnum, NULL, &loff.lnum, true, NULL);
           loff.fill = 0;
           n += wp->w_filler_rows;
           loff.height = 0;
@@ -381,7 +381,7 @@ void update_topline(win_T *wp)
             if (lnum <= 0 || line_count > wp->w_height_inner + 1) {
               break;
             }
-            (void)hasFolding(lnum, &lnum, NULL);
+            hasFolding(lnum, &lnum, NULL);
           }
         } else {
           line_count = wp->w_cursor.lnum - wp->w_botline + 1 + (int)(*so_ptr);
@@ -525,7 +525,7 @@ void set_topline(win_T *wp, linenr_T lnum)
   linenr_T prev_topline = wp->w_topline;
 
   // go to first of folded lines
-  (void)hasFoldingWin(wp, lnum, &lnum, NULL, true, NULL);
+  hasFoldingWin(wp, lnum, &lnum, NULL, true, NULL);
   // Approximate the value of w_botline
   wp->w_botline += lnum - wp->w_topline;
   wp->w_topline = lnum;
@@ -1207,7 +1207,7 @@ bool scrolldown(linenr_T line_count, int byfold)
   }
 
   // Make sure w_topline is at the first of a sequence of folded lines.
-  (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+  hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
   validate_cursor();            // w_wrow needs to be valid
   for (int todo = line_count; todo > 0; todo--) {
     if (curwin->w_topfill < win_get_fill(curwin, curwin->w_topline)
@@ -1332,11 +1332,11 @@ bool scrolldown(linenr_T line_count, int byfold)
 ///
 /// @param line_count number of lines to scroll
 /// @param byfold if true, count a closed fold as one line
-bool scrollup(linenr_T line_count, int byfold)
+bool scrollup(linenr_T line_count, bool byfold)
 {
   linenr_T topline = curwin->w_topline;
   linenr_T botline = curwin->w_botline;
-  int do_sms = curwin->w_p_wrap && curwin->w_p_sms;
+  bool do_sms = curwin->w_p_wrap && curwin->w_p_sms;
 
   if (do_sms || (byfold && hasAnyFolding(curwin)) || win_may_fill(curwin)) {
     int width1 = curwin->w_width_inner - curwin_col_off();
@@ -1359,7 +1359,7 @@ bool scrollup(linenr_T line_count, int byfold)
         linenr_T lnum = curwin->w_topline;
         if (byfold) {
           // for a closed fold: go to the last line in the fold
-          (void)hasFolding(lnum, NULL, &lnum);
+          hasFolding(lnum, NULL, &lnum);
         }
         if (lnum == curwin->w_topline && do_sms) {
           // 'smoothscroll': increase "w_skipcol" until it goes over
@@ -1415,7 +1415,7 @@ bool scrollup(linenr_T line_count, int byfold)
 
   if (hasAnyFolding(curwin)) {
     // Make sure w_topline is at the first of a sequence of folded lines.
-    (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+    hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
   }
 
   curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE);
@@ -1577,7 +1577,7 @@ static void max_topfill(void)
 // cursor off the screen.
 void scrolldown_clamp(void)
 {
-  int can_fill = (curwin->w_topfill < win_get_fill(curwin, curwin->w_topline));
+  bool can_fill = (curwin->w_topfill < win_get_fill(curwin, curwin->w_topline));
 
   if (curwin->w_topline <= 1
       && !can_fill) {
@@ -1609,7 +1609,7 @@ void scrolldown_clamp(void)
       curwin->w_topline--;
       curwin->w_topfill = 0;
     }
-    (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+    hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
     curwin->w_botline--;            // approximate w_botline
     curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE);
   }
@@ -1640,7 +1640,7 @@ void scrollup_clamp(void)
     if (curwin->w_topfill > 0) {
       curwin->w_topfill--;
     } else {
-      (void)hasFolding(curwin->w_topline, NULL, &curwin->w_topline);
+      hasFolding(curwin->w_topline, NULL, &curwin->w_topline);
       curwin->w_topline++;
     }
     curwin->w_botline++;                // approximate w_botline
@@ -1869,7 +1869,7 @@ void set_empty_rows(win_T *wp, int used)
 /// When scrolling scroll at least "min_scroll" lines.
 /// If "set_topbot" is true, set topline and botline first (for "zb").
 /// This is messy stuff!!!
-void scroll_cursor_bot(int min_scroll, int set_topbot)
+void scroll_cursor_bot(int min_scroll, bool set_topbot)
 {
   lineoff_T loff;
   linenr_T old_topline = curwin->w_topline;
@@ -1879,7 +1879,7 @@ void scroll_cursor_bot(int min_scroll, int set_topbot)
   int old_valid = curwin->w_valid;
   int old_empty_rows = curwin->w_empty_rows;
   linenr_T cln = curwin->w_cursor.lnum;  // Cursor Line Number
-  int do_sms = curwin->w_p_wrap && curwin->w_p_sms;
+  bool do_sms = curwin->w_p_wrap && curwin->w_p_sms;
 
   if (set_topbot) {
     bool set_skipcol = false;
@@ -2098,7 +2098,7 @@ void scroll_cursor_halfway(bool atend, bool prefer_above)
   linenr_T old_topline = curwin->w_topline;
   lineoff_T loff = { .lnum = curwin->w_cursor.lnum };
   lineoff_T boff = { .lnum = curwin->w_cursor.lnum };
-  (void)hasFolding(loff.lnum, &loff.lnum, &boff.lnum);
+  hasFolding(loff.lnum, &loff.lnum, &boff.lnum);
   int used = plines_win_nofill(curwin, loff.lnum, true);
   loff.fill = 0;
   boff.fill = 0;
@@ -2444,7 +2444,7 @@ int onepage(Direction dir, int count)
         botline_forw(curwin, &loff);
         botline_topline(&loff);
         // We're at the wrong end of a fold now.
-        (void)hasFoldingWin(curwin, loff.lnum, &loff.lnum, NULL, true, NULL);
+        hasFoldingWin(curwin, loff.lnum, &loff.lnum, NULL, true, NULL);
 
         // Always scroll at least one line.  Avoid getting stuck on
         // very long lines.
@@ -2491,10 +2491,10 @@ int onepage(Direction dir, int count)
       if (curwin->w_topline <= old_topline
           && old_topline < curbuf->b_ml.ml_line_count) {
         curwin->w_topline = old_topline + 1;
-        (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+        hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
       }
     } else if (curwin->w_botline > curbuf->b_ml.ml_line_count) {
-      (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+      hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
     }
   }
 
@@ -2593,7 +2593,7 @@ void halfpage(bool flag, linenr_T Prenum)
         if (n < 0 && scrolled > 0) {
           break;
         }
-        (void)hasFolding(curwin->w_topline, NULL, &curwin->w_topline);
+        hasFolding(curwin->w_topline, NULL, &curwin->w_topline);
         curwin->w_topline++;
         curwin->w_topfill = win_get_fill(curwin, curwin->w_topline);
 
@@ -2617,7 +2617,7 @@ void halfpage(bool flag, linenr_T Prenum)
           if (i > room) {
             break;
           }
-          (void)hasFolding(curwin->w_botline, NULL, &curwin->w_botline);
+          hasFolding(curwin->w_botline, NULL, &curwin->w_botline);
           curwin->w_botline++;
           room -= i;
         } while (curwin->w_botline <= curbuf->b_ml.ml_line_count);
@@ -2629,8 +2629,8 @@ void halfpage(bool flag, linenr_T Prenum)
       if (hasAnyFolding(curwin)) {
         while (--n >= 0
                && curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count) {
-          (void)hasFolding(curwin->w_cursor.lnum, NULL,
-                           &curwin->w_cursor.lnum);
+          hasFolding(curwin->w_cursor.lnum, NULL,
+                     &curwin->w_cursor.lnum);
           curwin->w_cursor.lnum++;
         }
       } else {
@@ -2652,7 +2652,7 @@ void halfpage(bool flag, linenr_T Prenum)
           break;
         }
         curwin->w_topline--;
-        (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+        hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
         curwin->w_topfill = 0;
       }
       curwin->w_valid &= ~(VALID_CROW|VALID_WROW|
@@ -2671,8 +2671,8 @@ void halfpage(bool flag, linenr_T Prenum)
       } else if (hasAnyFolding(curwin)) {
         while (--n >= 0 && curwin->w_cursor.lnum > 1) {
           curwin->w_cursor.lnum--;
-          (void)hasFolding(curwin->w_cursor.lnum,
-                           &curwin->w_cursor.lnum, NULL);
+          hasFolding(curwin->w_cursor.lnum,
+                     &curwin->w_cursor.lnum, NULL);
         }
       } else {
         curwin->w_cursor.lnum -= n;
diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index 3937533d36..88ebcbe690 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -702,7 +702,7 @@ static void normal_get_additional_char(NormalState *s)
   int *cp;
   bool repl = false;            // get character for replace mode
   bool lit = false;             // get extra character literally
-  int lang;                     // getting a text character
+  bool lang;                    // getting a text character
 
   no_mapping++;
   allow_keys++;                 // no mapping for nchar, but allow key codes
@@ -1027,7 +1027,7 @@ normal_end:
       restart_VIsual_select = 0;
     }
     if (restart_edit != 0 && !VIsual_active && s->old_mapped_len == 0) {
-      (void)edit(restart_edit, false, 1);
+      edit(restart_edit, false, 1);
     }
   }
 
@@ -1256,7 +1256,7 @@ static void normal_check_interrupt(NormalState *s)
     } else if (!global_busy || !exmode_active) {
       if (!quit_more) {
         // flush all buffers
-        (void)vgetc();
+        vgetc();
       }
       got_int = false;
     }
@@ -1847,7 +1847,7 @@ void clear_showcmd(void)
   }
 
   if (VIsual_active && !char_avail()) {
-    int cursor_bot = lt(VIsual, curwin->w_cursor);
+    bool cursor_bot = lt(VIsual, curwin->w_cursor);
     int lines;
     colnr_T leftcol, rightcol;
     linenr_T top, bot;
@@ -1861,8 +1861,8 @@ void clear_showcmd(void)
       bot = VIsual.lnum;
     }
     // Include closed folds as a whole.
-    (void)hasFolding(top, &top, NULL);
-    (void)hasFolding(bot, NULL, &bot);
+    hasFolding(top, &top, NULL);
+    hasFolding(bot, NULL, &bot);
     lines = bot - top + 1;
 
     if (VIsual_mode == Ctrl_V) {
@@ -2185,7 +2185,7 @@ void check_scrollbind(linenr_T topline_diff, int leftcol_diff)
 
     // do the horizontal scroll
     if (want_hor) {
-      (void)set_leftcol(tgt_leftcol);
+      set_leftcol(tgt_leftcol);
     }
   }
 
@@ -2256,7 +2256,7 @@ static void nv_page(cmdarg_T *cap)
       goto_tabpage(cap->count0);
     }
   } else {
-    (void)onepage(cap->arg, cap->count1);
+    onepage(cap->arg, cap->count1);
   }
 }
 
@@ -2606,7 +2606,7 @@ void nv_scroll_line(cmdarg_T *cap)
 }
 
 /// Scroll "count" lines up or down, and redraw.
-void scroll_redraw(int up, linenr_T count)
+void scroll_redraw(bool up, linenr_T count)
 {
   linenr_T prev_topline = curwin->w_topline;
   int prev_skipcol = curwin->w_skipcol;
@@ -2677,7 +2677,7 @@ static bool nv_z_get_count(cmdarg_T *cap, int *nchar_arg)
     LANGMAP_ADJUST(nchar, true);
     no_mapping--;
     allow_keys--;
-    (void)add_to_showcmd(nchar);
+    add_to_showcmd(nchar);
 
     if (nchar == K_DEL || nchar == K_KDEL) {
       n /= 10;
@@ -2722,7 +2722,7 @@ static int nv_zg_zw(cmdarg_T *cap, int nchar)
     LANGMAP_ADJUST(nchar, true);
     no_mapping--;
     allow_keys--;
-    (void)add_to_showcmd(nchar);
+    add_to_showcmd(nchar);
 
     if (vim_strchr("gGwW", nchar) == NULL) {
       clearopbeep(cap->oap);
@@ -2872,8 +2872,8 @@ static void nv_zet(cmdarg_T *cap)
   case 'h':
   case K_LEFT:
     if (!curwin->w_p_wrap) {
-      (void)set_leftcol((colnr_T)cap->count1 > curwin->w_leftcol
-                        ? 0 : curwin->w_leftcol - (colnr_T)cap->count1);
+      set_leftcol((colnr_T)cap->count1 > curwin->w_leftcol
+                  ? 0 : curwin->w_leftcol - (colnr_T)cap->count1);
     }
     break;
 
@@ -2886,7 +2886,7 @@ static void nv_zet(cmdarg_T *cap)
   case 'l':
   case K_RIGHT:
     if (!curwin->w_p_wrap) {
-      (void)set_leftcol(curwin->w_leftcol + (colnr_T)cap->count1);
+      set_leftcol(curwin->w_leftcol + (colnr_T)cap->count1);
     }
     break;
 
@@ -3288,8 +3288,8 @@ static void nv_ctrlo(cmdarg_T *cap)
 static void nv_hat(cmdarg_T *cap)
 {
   if (!checkclearopq(cap->oap)) {
-    (void)buflist_getfile(cap->count0, 0,
-                          GETF_SETMARK|GETF_ALT, false);
+    buflist_getfile(cap->count0, 0,
+                    GETF_SETMARK|GETF_ALT, false);
   }
 }
 
@@ -3554,7 +3554,7 @@ static void nv_ident(cmdarg_T *cap)
     init_history();
     add_to_history(HIST_SEARCH, buf, true, NUL);
 
-    (void)normal_search(cap, cmdchar == '*' ? '/' : '?', buf, 0, NULL);
+    normal_search(cap, cmdchar == '*' ? '/' : '?', buf, 0, NULL);
   } else {
     g_tag_at_cursor = true;
     do_cmdline_cmd(buf);
@@ -3638,8 +3638,8 @@ static void nv_scroll(cmdarg_T *cap)
         // Count a fold for one screen line.
         for (n = cap->count1 - 1; n > 0
              && curwin->w_cursor.lnum > curwin->w_topline; n--) {
-          (void)hasFolding(curwin->w_cursor.lnum,
-                           &curwin->w_cursor.lnum, NULL);
+          hasFolding(curwin->w_cursor.lnum,
+                     &curwin->w_cursor.lnum, NULL);
           if (curwin->w_cursor.lnum > curwin->w_topline) {
             curwin->w_cursor.lnum--;
           }
@@ -3680,7 +3680,7 @@ static void nv_scroll(cmdarg_T *cap)
         // Count a fold for one screen line.
         lnum = curwin->w_topline;
         while (n-- > 0 && lnum < curwin->w_botline - 1) {
-          (void)hasFolding(lnum, NULL, &lnum);
+          hasFolding(lnum, NULL, &lnum);
           lnum++;
         }
         n = lnum - curwin->w_topline;
@@ -3900,7 +3900,7 @@ static void nv_gotofile(cmdarg_T *cap)
   if (ptr != NULL) {
     // do autowrite if necessary
     if (curbufIsChanged() && curbuf->b_nwindows <= 1 && !buf_hide(curbuf)) {
-      (void)autowrite(curbuf, false);
+      autowrite(curbuf, false);
     }
     setpcmark();
     if (do_ecmd(0, ptr, NULL, NULL, ECMD_LAST,
@@ -3971,9 +3971,9 @@ static void nv_search(cmdarg_T *cap)
     return;
   }
 
-  (void)normal_search(cap, cap->cmdchar, cap->searchbuf,
-                      (cap->arg || !equalpos(save_cursor, curwin->w_cursor))
-                      ? 0 : SEARCH_MARK, NULL);
+  normal_search(cap, cap->cmdchar, cap->searchbuf,
+                (cap->arg || !equalpos(save_cursor, curwin->w_cursor))
+                ? 0 : SEARCH_MARK, NULL);
 }
 
 /// Handle "N" and "n" commands.
@@ -3989,7 +3989,7 @@ static void nv_next(cmdarg_T *cap)
     // an offset is given and the cursor is on the last char in the buffer:
     // Repeat with count + 1.
     cap->count1 += 1;
-    (void)normal_search(cap, 0, NULL, SEARCH_MARK | cap->arg, NULL);
+    normal_search(cap, 0, NULL, SEARCH_MARK | cap->arg, NULL);
     cap->count1 -= 1;
   }
 }
@@ -4123,7 +4123,7 @@ static void nv_bracket_block(cmdarg_T *cap, const pos_T *old_pos)
   if (cap->nchar == 'm' || cap->nchar == 'M') {
     int c;
     // norm is true for "]M" and "[m"
-    int norm = ((findc == '{') == (cap->nchar == 'm'));
+    bool norm = ((findc == '{') == (cap->nchar == 'm'));
 
     n = cap->count1;
     // found a match: we were inside a method
@@ -4289,9 +4289,9 @@ static void nv_brackets(cmdarg_T *cap)
   } else if (cap->nchar >= K_RIGHTRELEASE && cap->nchar <= K_LEFTMOUSE) {
     // [ or ] followed by a middle mouse click: put selected text with
     // indent adjustment.  Any other button just does as usual.
-    (void)do_mouse(cap->oap, cap->nchar,
-                   (cap->cmdchar == ']') ? FORWARD : BACKWARD,
-                   cap->count1, PUT_FIXINDENT);
+    do_mouse(cap->oap, cap->nchar,
+             (cap->cmdchar == ']') ? FORWARD : BACKWARD,
+             cap->count1, PUT_FIXINDENT);
   } else if (cap->nchar == 'z') {
     // "[z" and "]z": move to start or end of open fold.
     if (foldMoveTo(false, cap->cmdchar == ']' ? FORWARD : BACKWARD,
@@ -4556,7 +4556,7 @@ static void nv_replace(cmdarg_T *cap)
     // Insert the newline with an insert command, takes care of
     // autoindent.      The insert command depends on being on the last
     // character of a line or not.
-    (void)del_chars(cap->count1, false);        // delete the characters
+    del_chars(cap->count1, false);        // delete the characters
     stuffcharReadbuff('\r');
     stuffcharReadbuff(ESC);
 
@@ -5312,7 +5312,7 @@ static void nv_g_dollar_cmd(cmdarg_T *cap)
   } else {
     if (cap->count1 > 1) {
       // if it fails, let the cursor still move to the last char
-      (void)cursor_down(cap->count1 - 1, false);
+      cursor_down(cap->count1 - 1, false);
     }
     i = curwin->w_leftcol + curwin->w_width_inner - col_off - 1;
     coladvance((colnr_T)i);
@@ -5626,7 +5626,7 @@ static void nv_g_cmd(cmdarg_T *cap)
   case K_X2DRAG:
   case K_X2RELEASE:
     mod_mask = MOD_MASK_CTRL;
-    (void)do_mouse(oap, cap->nchar, BACKWARD, cap->count1, 0);
+    do_mouse(oap, cap->nchar, BACKWARD, cap->count1, 0);
     break;
 
   case K_IGNORE:
@@ -5699,12 +5699,12 @@ static void n_opencmd(cmdarg_T *cap)
 
   if (cap->cmdchar == 'O') {
     // Open above the first line of a folded sequence of lines
-    (void)hasFolding(curwin->w_cursor.lnum,
-                     &curwin->w_cursor.lnum, NULL);
+    hasFolding(curwin->w_cursor.lnum,
+               &curwin->w_cursor.lnum, NULL);
   } else {
     // Open below the last line of a folded sequence of lines
-    (void)hasFolding(curwin->w_cursor.lnum,
-                     NULL, &curwin->w_cursor.lnum);
+    hasFolding(curwin->w_cursor.lnum,
+               NULL, &curwin->w_cursor.lnum);
   }
   // trigger TextChangedI for the 'o/O' command
   curbuf->b_last_changedtick_i = buf_get_changedtick(curbuf);
@@ -6108,10 +6108,10 @@ static void nv_normal(cmdarg_T *cap)
 /// Don't even beep if we are canceling a command.
 static void nv_esc(cmdarg_T *cap)
 {
-  int no_reason = (cap->oap->op_type == OP_NOP
-                   && cap->opcount == 0
-                   && cap->count0 == 0
-                   && cap->oap->regname == 0);
+  bool no_reason = (cap->oap->op_type == OP_NOP
+                    && cap->opcount == 0
+                    && cap->count0 == 0
+                    && cap->oap->regname == 0);
 
   if (cap->arg) {               // true for CTRL-C
     if (restart_edit == 0 && cmdwin_type == 0 && !VIsual_active && no_reason) {
@@ -6618,6 +6618,6 @@ void normal_cmd(oparg_T *oap, bool toplevel)
   s.toplevel = toplevel;
   s.oa = *oap;
   normal_prepare(&s);
-  (void)normal_execute(&s.state, safe_vgetc());
+  normal_execute(&s.state, safe_vgetc());
   *oap = s.oa;
 }
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 4cce2e7ba6..5a83d7d247 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -213,7 +213,7 @@ int get_extra_op_char(int optype)
 }
 
 /// handle a shift operation
-void op_shift(oparg_T *oap, int curs_top, int amount)
+void op_shift(oparg_T *oap, bool curs_top, int amount)
 {
   int block_col = 0;
 
@@ -287,7 +287,7 @@ void op_shift(oparg_T *oap, int curs_top, int amount)
 /// leaves cursor on first blank in the line.
 ///
 /// @param call_changed_bytes  call changed_bytes()
-void shift_line(int left, int round, int amount, int call_changed_bytes)
+void shift_line(bool left, bool round, int amount, int call_changed_bytes)
 {
   const int sw_val = get_sw_value_indent(curbuf);
 
@@ -323,7 +323,7 @@ void shift_line(int left, int round, int amount, int call_changed_bytes)
   if (State & VREPLACE_FLAG) {
     change_indent(INDENT_SET, count, false, NUL, call_changed_bytes);
   } else {
-    (void)set_indent(count, call_changed_bytes ? SIN_CHANGED : 0);
+    set_indent(count, call_changed_bytes ? SIN_CHANGED : 0);
   }
 }
 
@@ -520,7 +520,7 @@ static void shift_block(oparg_T *oap, int amount)
 
 /// Insert string "s" (b_insert ? before : after) block :AKelly
 /// Caller must prepare for undo.
-static void block_insert(oparg_T *oap, char *s, int b_insert, struct block_def *bdp)
+static void block_insert(oparg_T *oap, char *s, bool b_insert, struct block_def *bdp)
 {
   int ts_val;
   int count = 0;                // extra spaces to replace a cut TAB
@@ -915,14 +915,14 @@ int do_record(int c)
     if (p != NULL) {
       // Remove escaping for K_SPECIAL in multi-byte chars.
       vim_unescape_ks(p);
-      (void)tv_dict_add_str(dict, S_LEN("regcontents"), p);
+      tv_dict_add_str(dict, S_LEN("regcontents"), p);
     }
 
     // Name of requested register, or empty string for unnamed operation.
     char buf[NUMBUFLEN + 2];
     buf[0] = (char)regname;
     buf[1] = NUL;
-    (void)tv_dict_add_str(dict, S_LEN("regname"), buf);
+    tv_dict_add_str(dict, S_LEN("regname"), buf);
     tv_dict_set_keys_readonly(dict);
 
     // Get the recorded key hits.  K_SPECIAL will be escaped, this
@@ -1702,8 +1702,8 @@ int op_delete(oparg_T *oap)
         }
       }
 
-      (void)del_bytes((colnr_T)n, !virtual_op,
-                      oap->op_type == OP_DELETE && !oap->is_VIsual);
+      del_bytes((colnr_T)n, !virtual_op,
+                oap->op_type == OP_DELETE && !oap->is_VIsual);
     } else {
       // delete characters between lines
       pos_T curpos;
@@ -1729,10 +1729,10 @@ int op_delete(oparg_T *oap)
       // delete from start of line until op_end
       int n = (oap->end.col + 1 - !oap->inclusive);
       curwin->w_cursor.col = 0;
-      (void)del_bytes((colnr_T)n, !virtual_op,
-                      oap->op_type == OP_DELETE && !oap->is_VIsual);
+      del_bytes((colnr_T)n, !virtual_op,
+                oap->op_type == OP_DELETE && !oap->is_VIsual);
       curwin->w_cursor = curpos;  // restore curwin->w_cursor
-      (void)do_join(2, false, false, false, false);
+      do_join(2, false, false, false, false);
       curbuf_splice_pending--;
       extmark_splice(curbuf, (int)startpos.lnum - 1, startpos.col,
                      (int)oap->line_count - 1, n, deleted_bytes,
@@ -1822,11 +1822,6 @@ static int op_replace(oparg_T *oap, int c)
 
   // block mode replace
   if (oap->motion_type == kMTBlockWise) {
-    int numc;
-    int num_chars;
-    char *newp;
-    char *oldp;
-    colnr_T oldlen;
     bd.is_MAX = (curwin->w_curswant == MAXCOL);
     for (; curwin->w_cursor.lnum <= oap->end.lnum; curwin->w_cursor.lnum++) {
       curwin->w_cursor.col = 0;       // make sure cursor position is valid
@@ -1857,7 +1852,7 @@ static int op_replace(oparg_T *oap, int c)
             && !bd.is_oneChar
             && bd.end_char_vcols > 0) ? bd.end_char_vcols - 1 : 0;
       // Figure out how many characters to replace.
-      numc = oap->end_vcol - oap->start_vcol + 1;
+      int numc = oap->end_vcol - oap->start_vcol + 1;
       if (bd.is_short && (!virtual_op || bd.is_MAX)) {
         numc -= (oap->end_vcol - bd.end_vcol) + 1;
       }
@@ -1873,11 +1868,11 @@ static int op_replace(oparg_T *oap, int c)
       }
 
       // Compute bytes needed, move character count to num_chars.
-      num_chars = numc;
+      int num_chars = numc;
       numc *= utf_char2len(c);
 
-      oldp = get_cursor_line_ptr();
-      oldlen = (int)strlen(oldp);
+      char *oldp = get_cursor_line_ptr();
+      colnr_T oldlen = (int)strlen(oldp);
 
       size_t newp_size = (size_t)bd.textcol + (size_t)bd.startspaces;
       if (had_ctrl_v_cr || (c != '\r' && c != '\n')) {
@@ -1887,7 +1882,7 @@ static int op_replace(oparg_T *oap, int c)
                                 - bd.textcol - bd.textlen);
         }
       }
-      newp = xmallocz(newp_size);
+      char *newp = xmallocz(newp_size);
       // copy up to deleted part
       memmove(newp, oldp, (size_t)bd.textcol);
       oldp += bd.textcol + bd.textlen;
@@ -2038,7 +2033,7 @@ static int op_replace(oparg_T *oap, int c)
 void op_tilde(oparg_T *oap)
 {
   struct block_def bd;
-  int did_change = false;
+  bool did_change = false;
 
   if (u_save((linenr_T)(oap->start.lnum - 1),
              (linenr_T)(oap->end.lnum + 1)) == FAIL) {
@@ -2050,7 +2045,7 @@ void op_tilde(oparg_T *oap)
     for (; pos.lnum <= oap->end.lnum; pos.lnum++) {
       block_prep(oap, &bd, pos.lnum, false);
       pos.col = bd.textcol;
-      int one_change = swapchars(oap->op_type, &pos, bd.textlen);
+      bool one_change = swapchars(oap->op_type, &pos, bd.textlen);
       did_change |= one_change;
     }
     if (did_change) {
@@ -2276,7 +2271,7 @@ void op_insert(oparg_T *oap, int count1)
 
   pos_T t1 = oap->start;
   const pos_T start_insert = curwin->w_cursor;
-  (void)edit(NUL, false, (linenr_T)count1);
+  edit(NUL, false, (linenr_T)count1);
 
   // When a tab was inserted, and the characters in front of the tab
   // have been converted to a tab as well, the column of the cursor
@@ -2478,9 +2473,6 @@ int op_change(oparg_T *oap)
 
     ins_len = (int)strlen(firstline) - pre_textlen;
     if (ins_len > 0) {
-      int offset;
-      char *newp;
-      char *oldp;
       // Subsequent calls to ml_get() flush the firstline data - take a
       // copy of the inserted text.
       char *ins_text = xmalloc((size_t)ins_len + 1);
@@ -2495,16 +2487,16 @@ int op_change(oparg_T *oap)
           // initial coladd offset as part of "startspaces"
           if (bd.is_short) {
             vpos.lnum = linenr;
-            (void)getvpos(&vpos, oap->start_vcol);
+            getvpos(&vpos, oap->start_vcol);
           } else {
             vpos.coladd = 0;
           }
-          oldp = ml_get(linenr);
-          newp = xmalloc(strlen(oldp) + (size_t)vpos.coladd
-                         + (size_t)ins_len + 1);
+          char *oldp = ml_get(linenr);
+          char *newp = xmalloc(strlen(oldp) + (size_t)vpos.coladd
+                               + (size_t)ins_len + 1);
           // copy up to block start
           memmove(newp, oldp, (size_t)bd.textcol);
-          offset = bd.textcol;
+          int offset = bd.textcol;
           memset(newp + offset, ' ', (size_t)vpos.coladd);
           offset += vpos.coladd;
           memmove(newp + offset, ins_text, (size_t)ins_len);
@@ -2842,17 +2834,17 @@ static void do_autocmd_textyankpost(oparg_T *oap, yankreg_T *reg)
     tv_list_append_string(list, reg->y_array[i], -1);
   }
   tv_list_set_lock(list, VAR_FIXED);
-  (void)tv_dict_add_list(dict, S_LEN("regcontents"), list);
+  tv_dict_add_list(dict, S_LEN("regcontents"), list);
 
   // Register type.
   char buf[NUMBUFLEN + 2];
   format_reg_type(reg->y_type, reg->y_width, buf, ARRAY_SIZE(buf));
-  (void)tv_dict_add_str(dict, S_LEN("regtype"), buf);
+  tv_dict_add_str(dict, S_LEN("regtype"), buf);
 
   // Name of requested register, or empty string for unnamed operation.
   buf[0] = (char)oap->regname;
   buf[1] = NUL;
-  (void)tv_dict_add_str(dict, S_LEN("regname"), buf);
+  tv_dict_add_str(dict, S_LEN("regname"), buf);
 
   // Motion type: inclusive or exclusive.
   tv_dict_add_bool(dict, S_LEN("inclusive"),
@@ -2861,11 +2853,11 @@ static void do_autocmd_textyankpost(oparg_T *oap, yankreg_T *reg)
   // Kind of operation: yank, delete, change).
   buf[0] = (char)get_op_char(oap->op_type);
   buf[1] = NUL;
-  (void)tv_dict_add_str(dict, S_LEN("operator"), buf);
+  tv_dict_add_str(dict, S_LEN("operator"), buf);
 
   // Selection type: visual or not.
-  (void)tv_dict_add_bool(dict, S_LEN("visual"),
-                         oap->is_VIsual ? kBoolVarTrue : kBoolVarFalse);
+  tv_dict_add_bool(dict, S_LEN("visual"),
+                   oap->is_VIsual ? kBoolVarTrue : kBoolVarFalse);
 
   tv_dict_set_keys_readonly(dict);
   textlock++;
@@ -2934,7 +2926,7 @@ void do_put(int regname, yankreg_T *reg, int dir, int count, int flags)
     if (flags & PUT_LINE) {
       stuffcharReadbuff(command_start_char);
       for (; count > 0; count--) {
-        (void)stuff_inserted(NUL, 1, count != 1);
+        stuff_inserted(NUL, 1, count != 1);
         if (count != 1) {
           // To avoid 'autoindent' affecting the text, use Ctrl_U to remove any
           // whitespace. Can't just insert Ctrl_U into readbuf1, this would go
@@ -2946,7 +2938,7 @@ void do_put(int regname, yankreg_T *reg, int dir, int count, int flags)
         }
       }
     } else {
-      (void)stuff_inserted(command_start_char, count, false);
+      stuff_inserted(command_start_char, count, false);
     }
 
     // Putting the text is done later, so can't move the cursor to the next
@@ -3124,9 +3116,9 @@ void do_put(int regname, yankreg_T *reg, int dir, int count, int flags)
     // Correct line number for closed fold.  Don't move the cursor yet,
     // u_save() uses it.
     if (dir == BACKWARD) {
-      (void)hasFolding(lnum, &lnum, NULL);
+      hasFolding(lnum, &lnum, NULL);
     } else {
-      (void)hasFolding(lnum, NULL, &lnum);
+      hasFolding(lnum, NULL, &lnum);
     }
     if (dir == FORWARD) {
       lnum++;
@@ -3350,13 +3342,11 @@ void do_put(int regname, yankreg_T *reg, int dir, int count, int flags)
     }
     curbuf->b_op_end.coladd = 0;
     if (flags & PUT_CURSEND) {
-      colnr_T len;
-
       curwin->w_cursor = curbuf->b_op_end;
       curwin->w_cursor.col++;
 
       // in Insert mode we might be after the NUL, correct for that
-      len = (colnr_T)strlen(get_cursor_line_ptr());
+      colnr_T len = (colnr_T)strlen(get_cursor_line_ptr());
       if (curwin->w_cursor.col > len) {
         curwin->w_cursor.col = len;
       }
@@ -3539,7 +3529,7 @@ void do_put(int regname, yankreg_T *reg, int dir, int count, int flags)
             } else if ((indent = get_indent() + indent_diff) < 0) {
               indent = 0;
             }
-            (void)set_indent(indent, SIN_NOMARK);
+            set_indent(indent, SIN_NOMARK);
             curwin->w_cursor = old_pos;
             // remember how many chars were removed
             if (cnt == count && i == y_size - 1) {
@@ -4379,7 +4369,7 @@ void op_addsub(oparg_T *oap, linenr_T Prenum1, bool g_cmd)
           length = oap->end.col - pos.col + 1;
         }
       }
-      int one_change = do_addsub(oap->op_type, &pos, length, amount);
+      bool one_change = do_addsub(oap->op_type, &pos, length, amount);
       if (one_change) {
         // Remember the start position of the first change.
         if (change_cnt == 0) {
@@ -4424,7 +4414,7 @@ void op_addsub(oparg_T *oap, linenr_T Prenum1, bool g_cmd)
 /// @param Prenum1 Amount of addition or subtraction.
 ///
 /// @return true if some character was changed.
-int do_addsub(int op_type, pos_T *pos, int length, linenr_T Prenum1)
+bool do_addsub(int op_type, pos_T *pos, int length, linenr_T Prenum1)
 {
   char *buf1 = NULL;
   char buf2[NUMBUFLEN];
@@ -4580,7 +4570,7 @@ int do_addsub(int op_type, pos_T *pos, int length, linenr_T Prenum1)
     curwin->w_cursor.col = col;
     startpos = curwin->w_cursor;
     did_change = true;
-    (void)del_char(false);
+    del_char(false);
     ins_char(firstdigit);
     endpos = curwin->w_cursor;
     curwin->w_cursor.col = col;
@@ -4688,7 +4678,7 @@ int do_addsub(int op_type, pos_T *pos, int length, linenr_T Prenum1)
         }
       }
       // del_char() will mark line needing displaying
-      (void)del_char(false);
+      del_char(false);
       c = gchar_cursor();
     }
 
@@ -5229,16 +5219,16 @@ static varnumber_T line_count_info(char *line, varnumber_T *wc, varnumber_T *cc,
   varnumber_T i;
   varnumber_T words = 0;
   varnumber_T chars = 0;
-  int is_word = 0;
+  bool is_word = false;
 
   for (i = 0; i < limit && line[i] != NUL;) {
     if (is_word) {
       if (ascii_isspace(line[i])) {
         words++;
-        is_word = 0;
+        is_word = false;
       }
     } else if (!ascii_isspace(line[i])) {
-      is_word = 1;
+      is_word = true;
     }
     chars++;
     i += utfc_ptr2len(line + i);
@@ -5526,7 +5516,7 @@ static void op_colon(oparg_T *oap)
     // When using !! on a closed fold the range ".!" works best to operate
     // on, it will be made the whole closed fold later.
     linenr_T endOfStartFold = oap->start.lnum;
-    (void)hasFolding(oap->start.lnum, NULL, &endOfStartFold);
+    hasFolding(oap->start.lnum, NULL, &endOfStartFold);
     if (oap->end.lnum != oap->start.lnum && oap->end.lnum != endOfStartFold) {
       // Make it a range with the end line.
       stuffcharReadbuff(',');
@@ -5745,7 +5735,7 @@ void do_pending_operator(cmdarg_T *cap, int old_col, bool gui_yank)
     const bool redo_yank = vim_strchr(p_cpo, CPO_YANK) != NULL && !gui_yank;
 
     // Avoid a problem with unwanted linebreaks in block mode
-    (void)reset_lbr();
+    reset_lbr();
     oap->is_VIsual = VIsual_active;
     if (oap->motion_force == 'V') {
       oap->motion_type = kMTLineWise;
@@ -6131,7 +6121,7 @@ void do_pending_operator(cmdarg_T *cap, int old_col, bool gui_yank)
         vim_beep(BO_OPER);
         CancelRedo();
       } else {
-        (void)op_delete(oap);
+        op_delete(oap);
         // save cursor line for undo if it wasn't saved yet
         if (oap->motion_type == kMTLineWise
             && has_format_option(FO_AUTO)
@@ -6150,7 +6140,7 @@ void do_pending_operator(cmdarg_T *cap, int old_col, bool gui_yank)
       } else {
         restore_lbr(lbr_saved);
         oap->excl_tr_ws = cap->cmdchar == 'z';
-        (void)op_yank(oap, !gui_yank);
+        op_yank(oap, !gui_yank);
       }
       check_cursor_col();
       break;
@@ -6281,7 +6271,7 @@ void do_pending_operator(cmdarg_T *cap, int old_col, bool gui_yank)
         op_insert(oap, cap->count1);
 
         // Reset linebreak, so that formatting works correctly.
-        (void)reset_lbr();
+        reset_lbr();
 
         // TODO(brammool): when inserting in several lines, should format all
         // the lines.
@@ -6355,7 +6345,7 @@ void do_pending_operator(cmdarg_T *cap, int old_col, bool gui_yank)
       if (!p_sol && oap->motion_type == kMTLineWise && !oap->end_adjusted
           && (oap->op_type == OP_LSHIFT || oap->op_type == OP_RSHIFT
               || oap->op_type == OP_DELETE)) {
-        (void)reset_lbr();
+        reset_lbr();
         coladvance(curwin->w_curswant = old_col);
       }
     } else {
@@ -6685,7 +6675,7 @@ static void set_clipboard(int name, yankreg_T *reg)
   tv_list_append_string(args, &regtype, 1);
   tv_list_append_string(args, ((char[]) { (char)name }), 1);
 
-  (void)eval_call_provider("clipboard", "set", args, true);
+  eval_call_provider("clipboard", "set", args, true);
 }
 
 /// Avoid slow things (clipboard) during batch operations (while/for-loops).
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 2c5f18a5e1..842f6502f8 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -420,7 +420,7 @@ void set_init_1(bool clean_arg)
 /// TODO(famiu): Refactor this when def_val uses OptVal.
 static void set_option_default(const OptIndex opt_idx, int opt_flags)
 {
-  int both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
+  bool both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
 
   // pointer to variable for current option
   vimoption_T *opt = &options[opt_idx];
@@ -616,8 +616,8 @@ void set_init_3(void)
   // Set 'shellpipe' and 'shellredir', depending on the 'shell' option.
   // This is done after other initializations, where 'shell' might have been
   // set, but only if they have not been set before.
-  int do_srr = !(options[kOptShellredir].flags & P_WAS_SET);
-  int do_sp = !(options[kOptShellpipe].flags & P_WAS_SET);
+  bool do_srr = !(options[kOptShellredir].flags & P_WAS_SET);
+  bool do_sp = !(options[kOptShellpipe].flags & P_WAS_SET);
 
   size_t len = 0;
   char *p = (char *)invocation_path_tail(p_sh, &len);
@@ -738,7 +738,7 @@ void ex_set(exarg_T *eap)
   if (eap->forceit) {
     flags |= OPT_ONECOLUMN;
   }
-  (void)do_set(eap->arg, flags);
+  do_set(eap->arg, flags);
 }
 
 /// Get the default value for a string option.
@@ -1674,18 +1674,18 @@ static char *option_expand(OptIndex opt_idx, char *val)
 static void didset_options(void)
 {
   // initialize the table for 'iskeyword' et.al.
-  (void)init_chartab();
+  init_chartab();
 
   didset_string_options();
 
-  (void)spell_check_msm();
-  (void)spell_check_sps();
-  (void)compile_cap_prog(curwin->w_s);
-  (void)did_set_spell_option(true);
+  spell_check_msm();
+  spell_check_sps();
+  compile_cap_prog(curwin->w_s);
+  did_set_spell_option(true);
   // set cedit_key
-  (void)did_set_cedit(NULL);
+  did_set_cedit(NULL);
   // initialize the table for 'breakat'.
-  (void)did_set_breakat(NULL);
+  did_set_breakat(NULL);
   didset_window_options(curwin, true);
 }
 
@@ -1696,17 +1696,17 @@ static void didset_options2(void)
   highlight_changed();
 
   // Parse default for 'fillchars'.
-  (void)set_fillchars_option(curwin, curwin->w_p_fcs, true);
+  set_fillchars_option(curwin, curwin->w_p_fcs, true);
 
   // Parse default for 'listchars'.
-  (void)set_listchars_option(curwin, curwin->w_p_lcs, true);
+  set_listchars_option(curwin, curwin->w_p_lcs, true);
 
   // Parse default for 'wildmode'.
   check_opt_wim();
   xfree(curbuf->b_p_vsts_array);
-  (void)tabstop_set(curbuf->b_p_vsts, &curbuf->b_p_vsts_array);
+  tabstop_set(curbuf->b_p_vsts, &curbuf->b_p_vsts_array);
   xfree(curbuf->b_p_vts_array);
-  (void)tabstop_set(curbuf->b_p_vts,  &curbuf->b_p_vts_array);
+  tabstop_set(curbuf->b_p_vts,  &curbuf->b_p_vts_array);
 }
 
 /// Check for string options that are NULL (normally only termcap options).
@@ -1852,7 +1852,7 @@ sctx_T *get_option_sctx(OptIndex opt_idx)
 /// window-local value.
 void set_option_sctx(OptIndex opt_idx, int opt_flags, sctx_T script_ctx)
 {
-  int both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
+  bool both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
   int indir = (int)options[opt_idx].indir;
   nlua_set_sctx(&script_ctx);
   LastSet last_set = {
@@ -2183,14 +2183,14 @@ static const char *did_set_laststatus(optset_T *args)
   // Also clear the cmdline to remove the ruler if there is one
   if (value == 3 && old_value != 3) {
     frame_new_height(topframe, topframe->fr_height - STATUS_HEIGHT, false, false);
-    (void)win_comp_pos();
+    win_comp_pos();
     clear_cmdline = true;
   }
   // When switching from global statusline, increase height of topframe by STATUS_HEIGHT
   // in order to to re-add the space that was previously taken by the global statusline
   if (old_value == 3 && value != 3) {
     frame_new_height(topframe, topframe->fr_height + STATUS_HEIGHT, false, false);
-    (void)win_comp_pos();
+    win_comp_pos();
   }
 
   last_status(false);  // (re)set last window status line.
@@ -2240,7 +2240,7 @@ static const char *did_set_lisp(optset_T *args)
 {
   buf_T *buf = (buf_T *)args->os_buf;
   // When 'lisp' option changes include/exclude '-' in keyword characters.
-  (void)buf_init_chartab(buf, false);          // ignore errors
+  buf_init_chartab(buf, false);          // ignore errors
   return NULL;
 }
 
@@ -2381,7 +2381,7 @@ static const char *did_set_paste(optset_T *args FUNC_ATTR_UNUSED)
       buf->b_p_vsts = buf->b_p_vsts_nopaste ? xstrdup(buf->b_p_vsts_nopaste) : empty_string_option;
       xfree(buf->b_p_vsts_array);
       if (buf->b_p_vsts && buf->b_p_vsts != empty_string_option) {
-        (void)tabstop_set(buf->b_p_vsts, &buf->b_p_vsts_array);
+        tabstop_set(buf->b_p_vsts, &buf->b_p_vsts_array);
       } else {
         buf->b_p_vsts_array = NULL;
       }
@@ -3522,7 +3522,7 @@ static const char *did_set_option(OptIndex opt_idx, void *varp, OptVal old_value
     set_option_varp(opt_idx, varp, old_value, true);
     // When resetting some values, need to act on it.
     if (restore_chartab) {
-      (void)buf_init_chartab(curbuf, true);
+      buf_init_chartab(curbuf, true);
     }
 
     // Unset new_value as it is no longer valid.
@@ -4385,7 +4385,7 @@ static int put_setstring(FILE *fd, char *cmd, char *name, char **valuep, uint64_
           if (fprintf(fd, "%s %s+=", cmd, name) < 0) {
             goto fail;
           }
-          (void)copy_option_part(&p, part, size, ",");
+          copy_option_part(&p, part, size, ",");
           if (put_escstr(fd, part, 2) == FAIL || put_eol(fd) == FAIL) {
             goto fail;
           }
@@ -5149,7 +5149,7 @@ void buf_copy_options(buf_T *buf, int flags)
       buf->b_p_vsts = xstrdup(p_vsts);
       COPY_OPT_SCTX(buf, BV_VSTS);
       if (p_vsts && p_vsts != empty_string_option) {
-        (void)tabstop_set(p_vsts, &buf->b_p_vsts_array);
+        tabstop_set(p_vsts, &buf->b_p_vsts_array);
       } else {
         buf->b_p_vsts_array = NULL;
       }
@@ -5198,7 +5198,7 @@ void buf_copy_options(buf_T *buf, int flags)
       buf->b_s.b_syn_isk = empty_string_option;
       buf->b_s.b_p_spc = xstrdup(p_spc);
       COPY_OPT_SCTX(buf, BV_SPC);
-      (void)compile_cap_prog(&buf->b_s);
+      compile_cap_prog(&buf->b_s);
       buf->b_s.b_p_spf = xstrdup(p_spf);
       COPY_OPT_SCTX(buf, BV_SPF);
       buf->b_s.b_p_spl = xstrdup(p_spl);
@@ -5260,7 +5260,7 @@ void buf_copy_options(buf_T *buf, int flags)
       if (dont_do_help) {
         buf->b_p_isk = save_p_isk;
         if (p_vts && p_vts != empty_string_option && !buf->b_p_vts_array) {
-          (void)tabstop_set(p_vts, &buf->b_p_vts_array);
+          tabstop_set(p_vts, &buf->b_p_vts_array);
         } else {
           buf->b_p_vts_array = NULL;
         }
@@ -5273,7 +5273,7 @@ void buf_copy_options(buf_T *buf, int flags)
         buf->b_p_vts = xstrdup(p_vts);
         COPY_OPT_SCTX(buf, BV_VTS);
         if (p_vts && p_vts != empty_string_option && !buf->b_p_vts_array) {
-          (void)tabstop_set(p_vts, &buf->b_p_vts_array);
+          tabstop_set(p_vts, &buf->b_p_vts_array);
         } else {
           buf->b_p_vts_array = NULL;
         }
@@ -5295,7 +5295,7 @@ void buf_copy_options(buf_T *buf, int flags)
 
   check_buf_options(buf);           // make sure we don't have NULLs
   if (did_isk) {
-    (void)buf_init_chartab(buf, false);
+    buf_init_chartab(buf, false);
   }
 }
 
diff --git a/src/nvim/optionstr.c b/src/nvim/optionstr.c
index 6886be3c25..9e4c0e6b0f 100644
--- a/src/nvim/optionstr.c
+++ b/src/nvim/optionstr.c
@@ -148,21 +148,21 @@ static char SHM_ALL[] = { SHM_RO, SHM_MOD, SHM_LINES,
 /// option values.
 void didset_string_options(void)
 {
-  (void)opt_strings_flags(p_cmp, p_cmp_values, &cmp_flags, true);
-  (void)opt_strings_flags(p_bkc, p_bkc_values, &bkc_flags, true);
-  (void)opt_strings_flags(p_bo, p_bo_values, &bo_flags, true);
-  (void)opt_strings_flags(p_ssop, p_ssop_values, &ssop_flags, true);
-  (void)opt_strings_flags(p_vop, p_ssop_values, &vop_flags, true);
-  (void)opt_strings_flags(p_fdo, p_fdo_values, &fdo_flags, true);
-  (void)opt_strings_flags(p_dy, p_dy_values, &dy_flags, true);
-  (void)opt_strings_flags(p_jop, p_jop_values, &jop_flags, true);
-  (void)opt_strings_flags(p_rdb, p_rdb_values, &rdb_flags, true);
-  (void)opt_strings_flags(p_tc, p_tc_values, &tc_flags, false);
-  (void)opt_strings_flags(p_tpf, p_tpf_values, &tpf_flags, true);
-  (void)opt_strings_flags(p_ve, p_ve_values, &ve_flags, true);
-  (void)opt_strings_flags(p_swb, p_swb_values, &swb_flags, true);
-  (void)opt_strings_flags(p_wop, p_wop_values, &wop_flags, true);
-  (void)opt_strings_flags(p_cb, p_cb_values, &cb_flags, true);
+  opt_strings_flags(p_cmp, p_cmp_values, &cmp_flags, true);
+  opt_strings_flags(p_bkc, p_bkc_values, &bkc_flags, true);
+  opt_strings_flags(p_bo, p_bo_values, &bo_flags, true);
+  opt_strings_flags(p_ssop, p_ssop_values, &ssop_flags, true);
+  opt_strings_flags(p_vop, p_ssop_values, &vop_flags, true);
+  opt_strings_flags(p_fdo, p_fdo_values, &fdo_flags, true);
+  opt_strings_flags(p_dy, p_dy_values, &dy_flags, true);
+  opt_strings_flags(p_jop, p_jop_values, &jop_flags, true);
+  opt_strings_flags(p_rdb, p_rdb_values, &rdb_flags, true);
+  opt_strings_flags(p_tc, p_tc_values, &tc_flags, false);
+  opt_strings_flags(p_tpf, p_tpf_values, &tpf_flags, true);
+  opt_strings_flags(p_ve, p_ve_values, &ve_flags, true);
+  opt_strings_flags(p_swb, p_swb_values, &swb_flags, true);
+  opt_strings_flags(p_wop, p_wop_values, &wop_flags, true);
+  opt_strings_flags(p_cb, p_cb_values, &cb_flags, true);
 }
 
 char *illegal_char(char *errbuf, size_t errbuflen, int c)
@@ -301,7 +301,7 @@ void set_string_option_direct(OptIndex opt_idx, const char *val, int opt_flags,
 
   assert(opt->var != &p_shada);
 
-  int both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
+  bool both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
   char *s = xstrdup(val);
   char **varp = (char **)get_varp_scope(opt, both ? OPT_LOCAL : opt_flags);
 
@@ -748,7 +748,7 @@ const char *did_set_backupcopy(optset_T *args)
         + ((*flags & BKC_YES) != 0)
         + ((*flags & BKC_NO) != 0) != 1) {
       // Must have exactly one of "auto", "yes"  and "no".
-      (void)opt_strings_flags(oldval, p_bkc_values, flags, true);
+      opt_strings_flags(oldval, p_bkc_values, flags, true);
       return e_invarg;
     }
   }
@@ -905,11 +905,11 @@ static const char *did_set_global_listfillchars(win_T *win, char *val, bool opt_
     // here, so ignore the return value.
     if (opt_lcs) {
       if (*wp->w_p_lcs == NUL) {
-        (void)set_listchars_option(wp, wp->w_p_lcs, true);
+        set_listchars_option(wp, wp->w_p_lcs, true);
       }
     } else {
       if (*wp->w_p_fcs == NUL) {
-        (void)set_fillchars_option(wp, wp->w_p_fcs, true);
+        set_fillchars_option(wp, wp->w_p_fcs, true);
       }
     }
   }
@@ -1220,7 +1220,7 @@ const char *did_set_display(optset_T *args FUNC_ATTR_UNUSED)
   if (opt_strings_flags(p_dy, p_dy_values, &dy_flags, true) != OK) {
     return e_invarg;
   }
-  (void)init_chartab();
+  init_chartab();
   msg_grid_validate();
   return NULL;
 }
@@ -1425,7 +1425,7 @@ int expand_set_foldcolumn(optexpand_T *args, int *numMatches, char ***matches)
 const char *did_set_foldexpr(optset_T *args)
 {
   win_T *win = (win_T *)args->os_win;
-  (void)did_set_optexpr(args);
+  did_set_optexpr(args);
   if (foldmethodIsExpr(win)) {
     foldUpdateAll(win);
   }
@@ -1973,7 +1973,7 @@ const char *did_set_sessionoptions(optset_T *args)
   if ((ssop_flags & SSOP_CURDIR) && (ssop_flags & SSOP_SESDIR)) {
     // Don't allow both "sesdir" and "curdir".
     const char *oldval = args->os_oldval.string.data;
-    (void)opt_strings_flags(oldval, p_ssop_values, &ssop_flags, true);
+    opt_strings_flags(oldval, p_ssop_values, &ssop_flags, true);
     return e_invarg;
   }
   return NULL;
diff --git a/src/nvim/os/env.c b/src/nvim/os/env.c
index 3c5d6d2159..34b2d89f0b 100644
--- a/src/nvim/os/env.c
+++ b/src/nvim/os/env.c
@@ -587,7 +587,7 @@ void expand_env_esc(char *restrict srcp, char *restrict dst, int dstlen, bool es
     if (src[0] == '`' && src[1] == '=') {
       var = src;
       src += 2;
-      (void)skip_expr(&src, NULL);
+      skip_expr(&src, NULL);
       if (*src == '`') {
         src++;
       }
@@ -1061,7 +1061,7 @@ size_t home_replace(const buf_T *const buf, const char *src, char *const dst, si
     size_t usedlen = 0;
     size_t flen = strlen(homedir_env_mod);
     char *fbuf = NULL;
-    (void)modify_fname(":p", false, &usedlen, &homedir_env_mod, &fbuf, &flen);
+    modify_fname(":p", false, &usedlen, &homedir_env_mod, &fbuf, &flen);
     flen = strlen(homedir_env_mod);
     assert(homedir_env_mod != homedir_env);
     if (vim_ispathsep(homedir_env_mod[flen - 1])) {
diff --git a/src/nvim/os/lang.c b/src/nvim/os/lang.c
index 20b60150ee..617ce4d3ea 100644
--- a/src/nvim/os/lang.c
+++ b/src/nvim/os/lang.c
@@ -100,9 +100,7 @@ static char *get_mess_env(void)
 /// Also do "v:lc_time"and "v:ctype".
 void set_lang_var(void)
 {
-  const char *loc;
-
-  loc = get_locale_val(LC_CTYPE);
+  const char *loc = get_locale_val(LC_CTYPE);
   set_vim_var_string(VV_CTYPE, loc, -1);
 
   loc = get_mess_env();
@@ -143,8 +141,6 @@ void init_locale(void)
 void ex_language(exarg_T *eap)
 {
   char *loc;
-  char *p;
-  char *name;
   int what = LC_ALL;
   char *whatstr = "";
 #ifdef LC_MESSAGES
@@ -153,12 +149,12 @@ void ex_language(exarg_T *eap)
 # define VIM_LC_MESSAGES 6789
 #endif
 
-  name = eap->arg;
+  char *name = eap->arg;
 
   // Check for "messages {name}", "ctype {name}" or "time {name}" argument.
   // Allow abbreviation, but require at least 3 characters to avoid
   // confusion with a two letter language name "me" or "ct".
-  p = skiptowhite(eap->arg);
+  char *p = skiptowhite(eap->arg);
   if ((*p == NUL || ascii_iswhite(*p)) && p - eap->arg >= 3) {
     if (STRNICMP(eap->arg, "messages", p - eap->arg) == 0) {
       what = VIM_LC_MESSAGES;
@@ -249,7 +245,6 @@ static bool did_init_locales = false;
 static char **find_locales(void)
 {
   garray_T locales_ga;
-  char *loc;
   char *saveptr = NULL;
 
   // Find all available locales by running command "locale -a".  If this
@@ -262,7 +257,7 @@ static char **find_locales(void)
 
   // Transform locale_a string where each locale is separated by "\n"
   // into an array of locale strings.
-  loc = os_strtok(locale_a, "\n", &saveptr);
+  char *loc = os_strtok(locale_a, "\n", &saveptr);
 
   while (loc != NULL) {
     loc = xstrdup(loc);
diff --git a/src/nvim/os/shell.c b/src/nvim/os/shell.c
index aa5075a79b..8f541a829d 100644
--- a/src/nvim/os/shell.c
+++ b/src/nvim/os/shell.c
@@ -119,14 +119,10 @@ int os_expand_wildcards(int num_pat, char **pat, int *num_file, char ***file, in
   int i;
   size_t len;
   char *p;
-  bool dir;
   char *extra_shell_arg = NULL;
   ShellOpts shellopts = kShellOptExpand | kShellOptSilent;
   int j;
   char *tempname;
-  char *command;
-  FILE *fd;
-  char *buffer;
 #define STYLE_ECHO      0       // use "echo", the default
 #define STYLE_GLOB      1       // use "glob", for csh
 #define STYLE_VIMGLOB   2       // use "vimglob", for Posix sh
@@ -242,7 +238,7 @@ int os_expand_wildcards(int num_pat, char **pat, int *num_file, char ***file, in
     len += sizeof("egin;" " end") - 1;
   }
 
-  command = xmalloc(len);
+  char *command = xmalloc(len);
 
   // Build the shell command:
   // - Set $nonomatch depending on EW_NOTFOUND (hopefully the shell
@@ -390,7 +386,7 @@ int os_expand_wildcards(int num_pat, char **pat, int *num_file, char ***file, in
   }
 
   // read the names from the file into memory
-  fd = fopen(tempname, READBIN);
+  FILE *fd = fopen(tempname, READBIN);
   if (fd == NULL) {
     // Something went wrong, perhaps a file name with a special char.
     if (!(flags & EW_SILENT)) {
@@ -417,7 +413,7 @@ int os_expand_wildcards(int num_pat, char **pat, int *num_file, char ***file, in
 #endif
   len = (size_t)templen;
   fseek(fd, 0, SEEK_SET);
-  buffer = xmalloc(len + 1);
+  char *buffer = xmalloc(len + 1);
   // fread() doesn't terminate buffer with NUL;
   // appropriate termination (not always NUL) is done below.
   size_t readlen = fread(buffer, 1, len, fd);
@@ -538,7 +534,7 @@ int os_expand_wildcards(int num_pat, char **pat, int *num_file, char ***file, in
     }
 
     // check if this entry should be included
-    dir = (os_isdir((*file)[i]));
+    bool dir = (os_isdir((*file)[i]));
     if ((dir && !(flags & EW_DIR)) || (!dir && !(flags & EW_FILE))) {
       continue;
     }
@@ -704,7 +700,7 @@ int os_call_shell(char *cmd, ShellOpts opts, char *extra_args)
   xfree(input.data);
 
   if (output) {
-    (void)write_output(output, nread, true);
+    write_output(output, nread, true);
     xfree(output);
   }
 
@@ -1144,7 +1140,7 @@ static void out_data_append_to_screen(char *output, size_t *count, bool eof)
         goto end;
       }
 
-      (void)msg_outtrans_len(p, i, 0);
+      msg_outtrans_len(p, i, 0);
       p += i;
     }
   }
diff --git a/src/nvim/path.c b/src/nvim/path.c
index be3a2dacb2..cb3d7045cb 100644
--- a/src/nvim/path.c
+++ b/src/nvim/path.c
@@ -717,7 +717,7 @@ static size_t do_path_expand(garray_T *gap, const char *path, size_t wildoff, in
       && *path_end == '/') {
     STRCPY(s, path_end + 1);
     stardepth++;
-    (void)do_path_expand(gap, buf, (size_t)(s - buf), flags, true);
+    do_path_expand(gap, buf, (size_t)(s - buf), flags, true);
     stardepth--;
   }
   *s = NUL;
@@ -746,7 +746,7 @@ static size_t do_path_expand(garray_T *gap, const char *path, size_t wildoff, in
           STRCPY(buf + len, "/**");  // NOLINT
           STRCPY(buf + len + 3, path_end);
           stardepth++;
-          (void)do_path_expand(gap, buf, len + 1, flags, true);
+          do_path_expand(gap, buf, len + 1, flags, true);
           stardepth--;
         }
 
@@ -754,7 +754,7 @@ static size_t do_path_expand(garray_T *gap, const char *path, size_t wildoff, in
         if (path_has_exp_wildcard(path_end)) {      // handle more wildcards
           // need to expand another component of the path
           // remove backslashes for the remaining components only
-          (void)do_path_expand(gap, buf, len + 1, flags, false);
+          do_path_expand(gap, buf, len + 1, flags, false);
         } else {
           FileInfo file_info;
 
@@ -1965,7 +1965,7 @@ bool same_directory(char *f1, char *f2)
     return false;
   }
 
-  (void)vim_FullName(f1, ffname, MAXPATHL, false);
+  vim_FullName(f1, ffname, MAXPATHL, false);
   t1 = path_tail_with_sep(ffname);
   t2 = path_tail_with_sep(f2);
   return t1 - ffname == t2 - f2
diff --git a/src/nvim/plines.c b/src/nvim/plines.c
index 461f69ae6c..2649977133 100644
--- a/src/nvim/plines.c
+++ b/src/nvim/plines.c
@@ -108,7 +108,7 @@ void win_linetabsize_cts(chartabsize_T *cts, colnr_T len)
   }
   // check for inline virtual text after the end of the line
   if (len == MAXCOL && cts->cts_has_virt_text && *cts->cts_ptr == NUL) {
-    (void)win_lbr_chartabsize(cts, NULL);
+    win_lbr_chartabsize(cts, NULL);
     cts->cts_vcol += cts->cts_cur_text_width_left + cts->cts_cur_text_width_right;
   }
 }
diff --git a/src/nvim/popupmenu.c b/src/nvim/popupmenu.c
index 6cc11c1175..04d95e1dc1 100644
--- a/src/nvim/popupmenu.c
+++ b/src/nvim/popupmenu.c
@@ -78,21 +78,20 @@ static void pum_compute_size(void)
   pum_kind_width = 0;
   pum_extra_width = 0;
   for (int i = 0; i < pum_size; i++) {
-    int w;
     if (pum_array[i].pum_text != NULL) {
-      w = vim_strsize(pum_array[i].pum_text);
+      int w = vim_strsize(pum_array[i].pum_text);
       if (pum_base_width < w) {
         pum_base_width = w;
       }
     }
     if (pum_array[i].pum_kind != NULL) {
-      w = vim_strsize(pum_array[i].pum_kind) + 1;
+      int w = vim_strsize(pum_array[i].pum_kind) + 1;
       if (pum_kind_width < w) {
         pum_kind_width = w;
       }
     }
     if (pum_array[i].pum_extra != NULL) {
-      w = vim_strsize(pum_array[i].pum_extra) + 1;
+      int w = vim_strsize(pum_array[i].pum_extra) + 1;
       if (pum_extra_width < w) {
         pum_extra_width = w;
       }
@@ -776,7 +775,7 @@ win_T *pum_set_info(int pum_idx, char *info)
   } else {
     // clean exist buffer
     while (!buf_is_empty(wp->w_buffer)) {
-      ml_delete_buf(wp->w_buffer, (linenr_T)1, false);
+      ml_delete_buf(wp->w_buffer, 1, false);
     }
   }
   no_u_sync--;
@@ -1139,13 +1138,13 @@ void pum_set_event_info(dict_T *dict)
     r = (double)pum_row;
     c = (double)pum_col;
   }
-  (void)tv_dict_add_float(dict, S_LEN("height"), h);
-  (void)tv_dict_add_float(dict, S_LEN("width"), w);
-  (void)tv_dict_add_float(dict, S_LEN("row"), r);
-  (void)tv_dict_add_float(dict, S_LEN("col"), c);
-  (void)tv_dict_add_nr(dict, S_LEN("size"), pum_size);
-  (void)tv_dict_add_bool(dict, S_LEN("scrollbar"),
-                         pum_scrollbar ? kBoolVarTrue : kBoolVarFalse);
+  tv_dict_add_float(dict, S_LEN("height"), h);
+  tv_dict_add_float(dict, S_LEN("width"), w);
+  tv_dict_add_float(dict, S_LEN("row"), r);
+  tv_dict_add_float(dict, S_LEN("col"), c);
+  tv_dict_add_nr(dict, S_LEN("size"), pum_size);
+  tv_dict_add_bool(dict, S_LEN("scrollbar"),
+                   pum_scrollbar ? kBoolVarTrue : kBoolVarFalse);
 }
 
 static void pum_position_at_mouse(int min_width)
diff --git a/src/nvim/profile.c b/src/nvim/profile.c
index 543f91304a..004454c984 100644
--- a/src/nvim/profile.c
+++ b/src/nvim/profile.c
@@ -254,7 +254,7 @@ void profile_reset(void)
   size_t todo = functbl->ht_used;
   hashitem_T *hi = functbl->ht_array;
 
-  for (; todo > (size_t)0; hi++) {
+  for (; todo > 0; hi++) {
     if (!HASHITEM_EMPTY(hi)) {
       todo--;
       ufunc_T *uf = HI2UF(hi);
@@ -797,7 +797,7 @@ void script_line_start(void)
   if (si->sn_prof_on && SOURCING_LNUM >= 1) {
     // Grow the array before starting the timer, so that the time spent
     // here isn't counted.
-    (void)ga_grow(&si->sn_prl_ga, SOURCING_LNUM - si->sn_prl_ga.ga_len);
+    ga_grow(&si->sn_prl_ga, SOURCING_LNUM - si->sn_prl_ga.ga_len);
     si->sn_prl_idx = SOURCING_LNUM - 1;
     while (si->sn_prl_ga.ga_len <= si->sn_prl_idx
            && si->sn_prl_ga.ga_len < si->sn_prl_ga.ga_maxlen) {
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index 59207dba17..0bd8ef6bcd 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -1603,7 +1603,7 @@ static int qf_parse_get_fields(char *linebuf, size_t linelen, efm_T *fmt_ptr, qf
   // Always ignore case when looking for a matching error.
   regmatch.rm_ic = true;
   regmatch.regprog = fmt_ptr->prog;
-  int r = vim_regexec(&regmatch, linebuf, 0);
+  bool r = vim_regexec(&regmatch, linebuf, 0);
   fmt_ptr->prog = regmatch.regprog;
   int status = QF_FAIL;
   if (r) {
@@ -1970,7 +1970,7 @@ static qf_info_T *ll_get_or_alloc_list(win_T *wp)
 /// For a location list command, returns the stack for the current window.  If
 /// the location list is not found, then returns NULL and prints an error
 /// message if 'print_emsg' is true.
-static qf_info_T *qf_cmd_get_stack(exarg_T *eap, int print_emsg)
+static qf_info_T *qf_cmd_get_stack(exarg_T *eap, bool print_emsg)
 {
   qf_info_T *qi = &ql_info;
 
@@ -2512,7 +2512,7 @@ static void win_set_loclist(win_T *wp, qf_info_T *qi)
 
 /// Find a help window or open one. If 'newwin' is true, then open a new help
 /// window.
-static int jump_to_help_window(qf_info_T *qi, bool newwin, int *opened_window)
+static int jump_to_help_window(qf_info_T *qi, bool newwin, bool *opened_window)
 {
   win_T *wp = NULL;
 
@@ -2715,7 +2715,7 @@ static void qf_goto_win_with_qfl_file(int qf_fnum)
 // window, jump to it. Otherwise open a new window to display the file. If
 // 'newwin' is true, then always open a new window. This is called from either
 // a quickfix or a location list window.
-static int qf_jump_to_usable_window(int qf_fnum, bool newwin, int *opened_window)
+static int qf_jump_to_usable_window(int qf_fnum, bool newwin, bool *opened_window)
 {
   win_T *usable_wp = NULL;
   bool usable_win = false;
@@ -2770,7 +2770,7 @@ static int qf_jump_to_usable_window(int qf_fnum, bool newwin, int *opened_window
 ///          QF_ABORT if the quickfix/location list was freed by an autocmd
 ///          when opening the buffer.
 static int qf_jump_edit_buffer(qf_info_T *qi, qfline_T *qf_ptr, int forceit, int prev_winid,
-                               int *opened_window)
+                               bool *opened_window)
 {
   qf_list_T *qfl = qf_get_curlist(qi);
   int old_changetick = qfl->qf_changedtick;
@@ -2905,7 +2905,7 @@ static void qf_jump_print_msg(qf_info_T *qi, int qf_index, qfline_T *qf_ptr, buf
 ///          FAIL if not able to jump/open a window.
 ///          NOTDONE if a file is not associated with the entry.
 ///          QF_ABORT if the quickfix/location list was modified by an autocmd.
-static int qf_jump_open_window(qf_info_T *qi, qfline_T *qf_ptr, bool newwin, int *opened_window)
+static int qf_jump_open_window(qf_info_T *qi, qfline_T *qf_ptr, bool newwin, bool *opened_window)
 {
   qf_list_T *qfl = qf_get_curlist(qi);
   int old_changetick = qfl->qf_changedtick;
@@ -2964,7 +2964,7 @@ static int qf_jump_open_window(qf_info_T *qi, qfline_T *qf_ptr, bool newwin, int
 ///          QF_ABORT if the quickfix/location list is freed by an autocmd when opening
 ///          the file.
 static int qf_jump_to_buffer(qf_info_T *qi, int qf_index, qfline_T *qf_ptr, int forceit,
-                             int prev_winid, int *opened_window, int openfold, int print_message)
+                             int prev_winid, bool *opened_window, int openfold, bool print_message)
 {
   // If there is a file name, read the wanted file if needed, and check
   // autowrite etc.
@@ -3051,7 +3051,7 @@ static void qf_jump_newwin(qf_info_T *qi, int dir, int errornr, int forceit, boo
 
   int prev_winid = curwin->handle;
 
-  int opened_window = false;
+  bool opened_window = false;
   int retval = qf_jump_open_window(qi, qf_ptr, newwin, &opened_window);
   if (retval == FAIL) {
     goto failed;
@@ -3988,7 +3988,7 @@ static void qf_update_buffer(qf_info_T *qi, qfline_T *old_last)
   buf_inc_changedtick(buf);
 
   if (old_last == NULL) {
-    (void)qf_win_pos_update(qi, 0);
+    qf_win_pos_update(qi, 0);
 
     // restore curwin/curbuf and a few other things
     aucmd_restbuf(&aco);
@@ -4199,7 +4199,7 @@ static void qf_fill_buffer(qf_list_T *qfl, buf_T *buf, qfline_T *old_last, int q
     }
     if (old_last == NULL) {
       // Delete the empty line which is now at the end
-      (void)ml_delete(lnum + 1, false);
+      ml_delete(lnum + 1, false);
     }
 
     qfga_clear();
@@ -4583,7 +4583,7 @@ int qf_get_cur_valid_idx(exarg_T *eap)
 /// Used by :cdo, :ldo, :cfdo and :lfdo commands.
 /// For :cdo and :ldo, returns the 'n'th valid error entry.
 /// For :cfdo and :lfdo, returns the 'n'th valid file entry.
-static size_t qf_get_nth_valid_entry(qf_list_T *qfl, size_t n, int fdo)
+static size_t qf_get_nth_valid_entry(qf_list_T *qfl, size_t n, bool fdo)
   FUNC_ATTR_NONNULL_ALL
 {
   // Check if the list has valid errors.
@@ -5706,7 +5706,7 @@ static buf_T *load_dummy_buffer(char *fname, char *dirname_start, char *resultin
     aucmd_prepbuf(&aco, newbuf);
 
     // Need to set the filename for autocommands.
-    (void)setfname(curbuf, fname, NULL, false);
+    setfname(curbuf, fname, NULL, false);
 
     // Create swap file now to avoid the ATTENTION message.
     check_need_swap(true);
@@ -5958,7 +5958,7 @@ static int qf_get_list_from_lines(dict_T *what, dictitem_T *di, dict_T *retdict)
 
   if (qf_init_ext(qi, 0, NULL, NULL, &di->di_tv, errorformat,
                   true, 0, 0, NULL, NULL) > 0) {
-    (void)get_errorlist(qi, NULL, 0, 0, l);
+    get_errorlist(qi, NULL, 0, 0, l);
     qf_free(&qi->qf_lists[0]);
   }
   xfree(qi);
@@ -7324,7 +7324,7 @@ static void get_qf_loc_list(bool is_qf, win_T *wp, typval_T *what_arg, typval_T
   if (what_arg->v_type == VAR_UNKNOWN) {
     tv_list_alloc_ret(rettv, kListLenMayKnow);
     if (is_qf || wp != NULL) {
-      (void)get_errorlist(NULL, wp, -1, 0, rettv->vval.v_list);
+      get_errorlist(NULL, wp, -1, 0, rettv->vval.v_list);
     }
   } else {
     tv_dict_alloc_ret(rettv);
diff --git a/src/nvim/rbuffer.c b/src/nvim/rbuffer.c
index d2fae5388f..ef286b3e22 100644
--- a/src/nvim/rbuffer.c
+++ b/src/nvim/rbuffer.c
@@ -213,7 +213,7 @@ int rbuffer_cmp(RBuffer *buf, const char *str, size_t count)
 {
   assert(count <= buf->size);
   size_t rcnt;
-  (void)rbuffer_read_ptr(buf, &rcnt);
+  rbuffer_read_ptr(buf, &rcnt);
   size_t n = MIN(count, rcnt);
   int rv = memcmp(str, buf->read_ptr, n);
   count -= n;
diff --git a/src/nvim/runtime.c b/src/nvim/runtime.c
index 29b70e05ca..d2e7af40e7 100644
--- a/src/nvim/runtime.c
+++ b/src/nvim/runtime.c
@@ -303,7 +303,7 @@ static bool source_callback_vim_lua(int num_fnames, char **fnames, bool all, voi
 
   for (int i = 0; i < num_fnames; i++) {
     if (path_with_extension(fnames[i], "vim")) {
-      (void)do_source(fnames[i], false, DOSO_NONE, cookie);
+      do_source(fnames[i], false, DOSO_NONE, cookie);
       did_one = true;
       if (!all) {
         return true;
@@ -313,7 +313,7 @@ static bool source_callback_vim_lua(int num_fnames, char **fnames, bool all, voi
 
   for (int i = 0; i < num_fnames; i++) {
     if (path_with_extension(fnames[i], "lua")) {
-      (void)do_source(fnames[i], false, DOSO_NONE, cookie);
+      do_source(fnames[i], false, DOSO_NONE, cookie);
       did_one = true;
       if (!all) {
         return true;
@@ -337,7 +337,7 @@ static bool source_callback(int num_fnames, char **fnames, bool all, void *cooki
   for (int i = 0; i < num_fnames; i++) {
     if (!path_with_extension(fnames[i], "vim")
         && !path_with_extension(fnames[i], "lua")) {
-      (void)do_source(fnames[i], false, DOSO_NONE, cookie);
+      do_source(fnames[i], false, DOSO_NONE, cookie);
       did_one = true;
       if (!all) {
         return true;
@@ -1804,7 +1804,7 @@ void ex_options(exarg_T *eap)
   bool multi_mods = 0;
 
   buf[0] = NUL;
-  (void)add_win_cmd_modifiers(buf, &cmdmod, &multi_mods);
+  add_win_cmd_modifiers(buf, &cmdmod, &multi_mods);
 
   os_setenv("OPTWIN_CMD", buf, 1);
   cmd_source(SYS_OPTWIN_FILE, NULL);
@@ -1845,7 +1845,7 @@ static FILE *fopen_noinh_readbin(char *filename)
     return NULL;
   }
 
-  (void)os_set_cloexec(fd_tmp);
+  os_set_cloexec(fd_tmp);
 
   return fdopen(fd_tmp, READBIN);
 }
@@ -2623,7 +2623,7 @@ static char *get_one_sourceline(struct source_cookie *sp)
   int c;
   char *buf;
 #ifdef USE_CRNL
-  int has_cr;                           // CR-LF found
+  bool has_cr;                           // CR-LF found
 #endif
   bool have_read = false;
 
diff --git a/src/nvim/search.c b/src/nvim/search.c
index 8279b4857c..c70aa60c74 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -101,7 +101,7 @@ static int last_idx = 0;        // index in spats[] for RE_LAST
 
 static uint8_t lastc[2] = { NUL, NUL };   // last character searched for
 static Direction lastcdir = FORWARD;      // last direction of character search
-static int last_t_cmd = true;             // last search t_cmd
+static bool last_t_cmd = true;            // last search t_cmd
 static char lastc_bytes[MB_MAXBYTES + 1];
 static int lastc_bytelen = 1;             // >1 for multi-byte char
 
@@ -388,7 +388,7 @@ bool pat_has_uppercase(char *pat)
   magic_T magic_val = MAGIC_ON;
 
   // get the magicness of the pattern
-  (void)skip_regexp_ex(pat, NUL, magic_isset(), NULL, NULL, &magic_val);
+  skip_regexp_ex(pat, NUL, magic_isset(), NULL, NULL, &magic_val);
 
   while (*p != NUL) {
     const int l = utfc_ptr2len(p);
@@ -436,7 +436,7 @@ int last_csearch_forward(void)
 
 int last_csearch_until(void)
 {
-  return last_t_cmd == true;
+  return last_t_cmd;
 }
 
 void set_last_csearch(int c, char *s, int len)
@@ -474,7 +474,7 @@ void reset_search_dir(void)
 
 // Set the last search pattern.  For ":let @/ =" and ShaDa file.
 // Also set the saved search pattern, so that this works in an autocommand.
-void set_last_search_pat(const char *s, int idx, int magic, int setlast)
+void set_last_search_pat(const char *s, int idx, int magic, bool setlast)
 {
   free_spat(&spats[idx]);
   // An empty string means that nothing should be matched.
@@ -521,7 +521,7 @@ void last_pat_prog(regmmatch_T *regmatch)
     return;
   }
   emsg_off++;           // So it doesn't beep if bad expr
-  (void)search_regcomp("", NULL, 0, last_idx, SEARCH_KEEP, regmatch);
+  search_regcomp("", NULL, 0, last_idx, SEARCH_KEEP, regmatch);
   emsg_off--;
 }
 
@@ -1495,7 +1495,7 @@ int search_for_exact_line(buf_T *buf, pos_T *pos, Direction dir, char *pat)
 /// position of the character, otherwise move to just before the char.
 /// Do this "cap->count1" times.
 /// Return FAIL or OK.
-int searchc(cmdarg_T *cap, int t_cmd)
+int searchc(cmdarg_T *cap, bool t_cmd)
   FUNC_ATTR_NONNULL_ALL
 {
   int c = cap->nchar;                   // char to search for
@@ -2518,7 +2518,7 @@ int current_search(int count, bool forward)
 /// else from position "cur".
 /// "direction" is FORWARD or BACKWARD.
 /// Returns true, false or -1 for failure.
-static int is_zero_width(char *pattern, int move, pos_T *cur, Direction direction)
+static int is_zero_width(char *pattern, bool move, pos_T *cur, Direction direction)
 {
   regmmatch_T regmatch;
   int result = -1;
@@ -2574,8 +2574,8 @@ static int is_zero_width(char *pattern, int move, pos_T *cur, Direction directio
   return result;
 }
 
-/// return true if line 'lnum' is empty or has white chars only.
-int linewhite(linenr_T lnum)
+/// @return  true if line 'lnum' is empty or has white chars only.
+bool linewhite(linenr_T lnum)
 {
   char *p = skipwhite(ml_get(lnum));
   return *p == NUL;
@@ -3557,7 +3557,6 @@ void find_pattern_in_path(char *ptr, Direction dir, size_t len, bool whole, bool
   char *curr_fname = curbuf->b_fname;
   char *prev_fname = NULL;
   int depth_displayed;                  // For type==CHECK_PATH
-  int already_searched;
   char *p;
   bool define_matched;
   regmatch_T regmatch;
@@ -3643,7 +3642,7 @@ void find_pattern_in_path(char *ptr, Direction dir, size_t len, bool whole, bool
                                       FNAME_EXP|FNAME_INCL|FNAME_REL, 1, p_fname,
                                       NULL);
       }
-      already_searched = false;
+      bool already_searched = false;
       if (new_fname != NULL) {
         // Check whether we have already searched in this file
         for (i = 0;; i++) {
diff --git a/src/nvim/shada.c b/src/nvim/shada.c
index efef6f8511..4aa4d83e0e 100644
--- a/src/nvim/shada.c
+++ b/src/nvim/shada.c
@@ -1252,7 +1252,7 @@ static void shada_read(ShaDaReadDef *const sd_reader, const int flags)
       // string is close to useless: you can only use it with :& or :~ and
       // that’s all because s//~ is not available until the first call to
       // regtilde. Vim was not calling this for some reason.
-      (void)regtilde(cur_entry.data.sub_string.sub, magic_isset(), false);
+      regtilde(cur_entry.data.sub_string.sub, magic_isset(), false);
       // Do not free shada entry: its allocated memory was saved above.
       break;
     case kSDItemHistoryEntry:
@@ -4024,7 +4024,7 @@ static bool shada_removable(const char *name)
 
   char *new_name = home_replace_save(NULL, name);
   for (char *p = p_shada; *p;) {
-    (void)copy_option_part(&p, part, ARRAY_SIZE(part), ", ");
+    copy_option_part(&p, part, ARRAY_SIZE(part), ", ");
     if (part[0] == 'r') {
       home_replace(NULL, part + 1, NameBuff, MAXPATHL, true);
       size_t n = strlen(NameBuff);
diff --git a/src/nvim/sign.c b/src/nvim/sign.c
index 690da8999e..1b33848e34 100644
--- a/src/nvim/sign.c
+++ b/src/nvim/sign.c
@@ -719,7 +719,7 @@ static void sign_jump_cmd(buf_T *buf, linenr_T lnum, const char *name, int id, c
     return;
   }
 
-  (void)sign_jump(id, group, buf);
+  sign_jump(id, group, buf);
 }
 
 /// Parse the command line arguments for the ":sign place", ":sign unplace" and
diff --git a/src/nvim/spell.c b/src/nvim/spell.c
index c322621038..5e8ace3f60 100644
--- a/src/nvim/spell.c
+++ b/src/nvim/spell.c
@@ -176,7 +176,7 @@ typedef struct syl_item_S {
 } syl_item_T;
 
 spelltab_T spelltab;
-int did_set_spelltab;
+bool did_set_spelltab;
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "spell.c.generated.h"
@@ -297,8 +297,8 @@ size_t spell_check(win_T *wp, char *ptr, hlf_T *attrp, int *capcol, bool docount
     MB_PTR_ADV(mi.mi_fend);
   }
 
-  (void)spell_casefold(wp, ptr, (int)(mi.mi_fend - ptr), mi.mi_fword,
-                       MAXWLEN + 1);
+  spell_casefold(wp, ptr, (int)(mi.mi_fend - ptr), mi.mi_fword,
+                 MAXWLEN + 1);
   mi.mi_fwordlen = (int)strlen(mi.mi_fword);
 
   if (is_camel_case && mi.mi_fwordlen > 0) {
@@ -363,7 +363,7 @@ size_t spell_check(win_T *wp, char *ptr, hlf_T *attrp, int *capcol, bool docount
         // Check for end of sentence.
         regmatch.regprog = wp->w_s->b_cap_prog;
         regmatch.rm_ic = false;
-        int r = vim_regexec(&regmatch, ptr, 0);
+        bool r = vim_regexec(&regmatch, ptr, 0);
         wp->w_s->b_cap_prog = regmatch.regprog;
         if (r) {
           *capcol = (int)(regmatch.endp[0] - ptr);
@@ -802,7 +802,7 @@ static void find_word(matchinf_T *mip, int mode)
           if (slang->sl_compsylmax < MAXWLEN) {
             // "fword" is only needed for checking syllables.
             if (ptr == mip->mi_word) {
-              (void)spell_casefold(mip->mi_win, ptr, wlen, fword, MAXWLEN);
+              spell_casefold(mip->mi_win, ptr, wlen, fword, MAXWLEN);
             } else {
               xstrlcpy(fword, ptr, (size_t)endlen[endidxcnt] + 1);
             }
@@ -1212,9 +1212,9 @@ static int fold_more(matchinf_T *mip)
     MB_PTR_ADV(mip->mi_fend);
   }
 
-  (void)spell_casefold(mip->mi_win, p, (int)(mip->mi_fend - p),
-                       mip->mi_fword + mip->mi_fwordlen,
-                       MAXWLEN - mip->mi_fwordlen);
+  spell_casefold(mip->mi_win, p, (int)(mip->mi_fend - p),
+                 mip->mi_fword + mip->mi_fwordlen,
+                 MAXWLEN - mip->mi_fwordlen);
   int flen = (int)strlen(mip->mi_fword + mip->mi_fwordlen);
   mip->mi_fwordlen += flen;
   return flen;
@@ -1272,7 +1272,7 @@ static TriState decor_spell_nav_col(win_T *wp, linenr_T lnum, linenr_T *decor_ln
 static inline bool can_syn_spell(win_T *wp, linenr_T lnum, int col)
 {
   bool can_spell;
-  (void)syn_get_id(wp, lnum, col, false, &can_spell, false);
+  syn_get_id(wp, lnum, col, false, &can_spell, false);
   return can_spell;
 }
 
@@ -1293,7 +1293,7 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
   size_t found_len = 0;
   hlf_T attr = HLF_COUNT;
   size_t len;
-  int has_syntax = syntax_present(wp);
+  bool has_syntax = syntax_present(wp);
   colnr_T col;
   char *buf = NULL;
   size_t buflen = 0;
@@ -2029,7 +2029,7 @@ char *parse_spelllang(win_T *wp)
     // If not found try loading the language now.
     if (slang == NULL) {
       if (filename) {
-        (void)spell_load_file(lang, lang, NULL, false);
+        spell_load_file(lang, lang, NULL, false);
       } else {
         spell_load_lang(lang);
         // SpellFileMissing autocommands may do anything, including
@@ -2374,7 +2374,7 @@ void spell_reload(void)
     // window for this buffer in which 'spell' is set.
     if (*wp->w_s->b_p_spl != NUL) {
       if (wp->w_p_spell) {
-        (void)parse_spelllang(wp);
+        parse_spelllang(wp);
         break;
       }
     }
@@ -2834,7 +2834,7 @@ void spell_soundfold(slang_T *slang, char *inword, bool folded, char *res)
     if (folded) {
       word = inword;
     } else {
-      (void)spell_casefold(curwin, inword, (int)strlen(inword), fword, MAXWLEN);
+      spell_casefold(curwin, inword, (int)strlen(inword), fword, MAXWLEN);
       word = fword;
     }
 
diff --git a/src/nvim/spell.h b/src/nvim/spell.h
index 43ba00e901..1462c45f5c 100644
--- a/src/nvim/spell.h
+++ b/src/nvim/spell.h
@@ -11,7 +11,7 @@ extern slang_T *first_lang;
 extern char *int_wordlist;
 
 extern spelltab_T spelltab;
-extern int did_set_spelltab;
+extern bool did_set_spelltab;
 
 extern char *e_format;
 
diff --git a/src/nvim/spellfile.c b/src/nvim/spellfile.c
index 0cffd5741e..ac9ac689ed 100644
--- a/src/nvim/spellfile.c
+++ b/src/nvim/spellfile.c
@@ -2015,16 +2015,16 @@ static afffile_T *spell_read_aff(spellinfo_T *spin, char *fname)
   spell_message(spin, IObuff);
 
   // Only do REP lines when not done in another .aff file already.
-  int do_rep = GA_EMPTY(&spin->si_rep);
+  bool do_rep = GA_EMPTY(&spin->si_rep);
 
   // Only do REPSAL lines when not done in another .aff file already.
-  int do_repsal = GA_EMPTY(&spin->si_repsal);
+  bool do_repsal = GA_EMPTY(&spin->si_repsal);
 
   // Only do SAL lines when not done in another .aff file already.
-  int do_sal = GA_EMPTY(&spin->si_sal);
+  bool do_sal = GA_EMPTY(&spin->si_sal);
 
   // Only do MAP lines when not done in another .aff file already.
-  int do_mapline = GA_EMPTY(&spin->si_map);
+  bool do_mapline = GA_EMPTY(&spin->si_map);
 
   // Allocate and init the afffile_T structure.
   afffile_T *aff = getroom(spin, sizeof(*aff), true);
@@ -2967,9 +2967,9 @@ static void add_fromto(spellinfo_T *spin, garray_T *gap, char *from, char *to)
   char word[MAXWLEN];
 
   fromto_T *ftp = GA_APPEND_VIA_PTR(fromto_T, gap);
-  (void)spell_casefold(curwin, from, (int)strlen(from), word, MAXWLEN);
+  spell_casefold(curwin, from, (int)strlen(from), word, MAXWLEN);
   ftp->ft_from = getroom_save(spin, word);
-  (void)spell_casefold(curwin, to, (int)strlen(to), word, MAXWLEN);
+  spell_casefold(curwin, to, (int)strlen(to), word, MAXWLEN);
   ftp->ft_to = getroom_save(spin, word);
 }
 
@@ -3614,11 +3614,9 @@ static int spell_read_wordfile(spellinfo_T *spin, char *fname)
           smsg(0, _("/encoding= line after word ignored in %s line %" PRIdLINENR ": %s"),
                fname, lnum, line - 1);
         } else {
-          char *enc;
-
           // Setup for conversion to 'encoding'.
           line += 9;
-          enc = enc_canonize(line);
+          char *enc = enc_canonize(line);
           if (!spin->si_ascii
               && convert_setup(&spin->si_conv, enc, p_enc) == FAIL) {
             smsg(0, _("Conversion in %s not supported: from %s to %s"),
@@ -3820,7 +3818,7 @@ static int store_word(spellinfo_T *spin, char *word, int flags, int region, cons
     return FAIL;
   }
 
-  (void)spell_casefold(curwin, word, len, foldword, MAXWLEN);
+  spell_casefold(curwin, word, len, foldword, MAXWLEN);
   for (const char *p = pfxlist; res == OK; p++) {
     if (!need_affix || (p != NULL && *p != NUL)) {
       res = tree_add_word(spin, foldword, spin->si_foldroot, ct | flags,
@@ -4593,7 +4591,7 @@ static int write_vim_spell(spellinfo_T *spin, char *fname)
     spin->si_memtot += (int)(nodecount + nodecount * sizeof(int));
 
     // Write the nodes.
-    (void)put_node(fd, tree, 0, regionmask, round == 3);
+    put_node(fd, tree, 0, regionmask, round == 3);
   }
 
   // Write another byte to check for errors (file system full).
@@ -5098,7 +5096,7 @@ static void sug_write(spellinfo_T *spin, char *fname)
   spin->si_memtot += (int)(nodecount + nodecount * sizeof(int));
 
   // Write the nodes.
-  (void)put_node(fd, tree, 0, 0, false);
+  put_node(fd, tree, 0, 0, false);
 
   // <SUGTABLE>: <sugwcount> <sugline> ...
   linenr_T wcount = spin->si_spellbuf->b_ml.ml_line_count;
@@ -5638,7 +5636,7 @@ static void set_spell_charflags(const char *flags_in, int cnt, const char *fol)
     }
   }
 
-  (void)set_spell_finish(&new_st);
+  set_spell_finish(&new_st);
 }
 
 static int set_spell_finish(spelltab_T *new_st)
diff --git a/src/nvim/spellsuggest.c b/src/nvim/spellsuggest.c
index c4be6f2ec7..f1fac5730d 100644
--- a/src/nvim/spellsuggest.c
+++ b/src/nvim/spellsuggest.c
@@ -442,7 +442,7 @@ void spell_suggest(int count)
   char wcopy[MAXWLEN + 2];
   suginfo_T sug;
   suggest_T *stp;
-  int mouse_used;
+  bool mouse_used;
   int limit;
   int selected = count;
   int badlen = 0;
@@ -730,8 +730,8 @@ static void spell_find_suggest(char *badptr, int badlen, suginfo_T *su, int maxc
     su->su_badlen = MAXWLEN - 1;        // just in case
   }
   xstrlcpy(su->su_badword, su->su_badptr, (size_t)su->su_badlen + 1);
-  (void)spell_casefold(curwin, su->su_badptr, su->su_badlen, su->su_fbadword,
-                       MAXWLEN);
+  spell_casefold(curwin, su->su_badptr, su->su_badlen, su->su_fbadword,
+                 MAXWLEN);
 
   // TODO(vim): make this work if the case-folded text is longer than the
   // original text. Currently an illegal byte causes wrong pointer
@@ -845,7 +845,7 @@ static void spell_suggest_expr(suginfo_T *su, char *expr)
 
   // Remove bogus suggestions, sort and truncate at "maxcount".
   check_suggestions(su, &su->su_ga);
-  (void)cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
+  cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
 }
 
 /// Find suggestions in file "fname".  Used for "file:" in 'spellsuggest'.
@@ -892,7 +892,7 @@ static void spell_suggest_file(suginfo_T *su, char *fname)
 
   // Remove bogus suggestions, sort and truncate at "maxcount".
   check_suggestions(su, &su->su_ga);
-  (void)cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
+  cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
 }
 
 /// Find suggestions for the internal method indicated by "sps_flags".
@@ -956,7 +956,7 @@ static void spell_suggest_intern(suginfo_T *su, bool interactive)
   // got_int when using a command, not for spellsuggest().
   os_breakcheck();
   if (interactive && got_int) {
-    (void)vgetc();
+    vgetc();
     got_int = false;
   }
 
@@ -968,7 +968,7 @@ static void spell_suggest_intern(suginfo_T *su, bool interactive)
 
     // Remove bogus suggestions, sort and truncate at "maxcount".
     check_suggestions(su, &su->su_ga);
-    (void)cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
+    cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
   }
 }
 
@@ -1064,7 +1064,7 @@ static void suggest_try_change(suginfo_T *su)
   STRCPY(fword, su->su_fbadword);
   int n = (int)strlen(fword);
   char *p = su->su_badptr + su->su_badlen;
-  (void)spell_casefold(curwin, p, (int)strlen(p), fword + n, MAXWLEN - n);
+  spell_casefold(curwin, p, (int)strlen(p), fword + n, MAXWLEN - n);
 
   // Make sure the resulting text is not longer than the original text.
   n = (int)strlen(su->su_badptr);
@@ -1272,10 +1272,10 @@ static void suggest_trie_walk(suginfo_T *su, langp_T *lp, char *fword, bool soun
         break;
       }
 
-      int fword_ends = (fword[sp->ts_fidx] == NUL
-                        || (soundfold
-                            ? ascii_iswhite(fword[sp->ts_fidx])
-                            : !spell_iswordp(fword + sp->ts_fidx, curwin)));
+      bool fword_ends = (fword[sp->ts_fidx] == NUL
+                         || (soundfold
+                             ? ascii_iswhite(fword[sp->ts_fidx])
+                             : !spell_iswordp(fword + sp->ts_fidx, curwin)));
       tword[sp->ts_twordlen] = NUL;
 
       if (sp->ts_prefixdepth <= PFD_NOTSPECIAL
@@ -2538,8 +2538,8 @@ static void score_combine(suginfo_T *su)
   }
 
   if (slang == NULL) {  // Using "double" without sound folding.
-    (void)cleanup_suggestions(&su->su_ga, su->su_maxscore,
-                              su->su_maxcount);
+    cleanup_suggestions(&su->su_ga, su->su_maxscore,
+                        su->su_maxcount);
     return;
   }
 
@@ -2558,9 +2558,9 @@ static void score_combine(suginfo_T *su)
   // Remove bad suggestions, sort the suggestions and truncate at "maxcount"
   // for both lists.
   check_suggestions(su, &su->su_ga);
-  (void)cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
+  cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
   check_suggestions(su, &su->su_sga);
-  (void)cleanup_suggestions(&su->su_sga, su->su_maxscore, su->su_maxcount);
+  cleanup_suggestions(&su->su_sga, su->su_maxscore, su->su_maxcount);
 
   ga_init(&ga, (int)sizeof(suginfo_T), 1);
   ga_grow(&ga, su->su_ga.ga_len + su->su_sga.ga_len);
@@ -2621,7 +2621,7 @@ static int stp_sal_score(suggest_T *stp, suginfo_T *su, slang_T *slang, char *ba
     pbad = badsound;
   } else {
     // soundfold the bad word with more characters following
-    (void)spell_casefold(curwin, su->su_badptr, stp->st_orglen, fword, MAXWLEN);
+    spell_casefold(curwin, su->su_badptr, stp->st_orglen, fword, MAXWLEN);
 
     // When joining two words the sound often changes a lot.  E.g., "t he"
     // sounds like "t h" while "the" sounds like "@".  Avoid that by
@@ -3148,7 +3148,7 @@ static void check_suggestions(suginfo_T *su, garray_T *gap)
     int len = stp[i].st_wordlen;
     xstrlcpy(longword + len, su->su_badptr + stp[i].st_orglen, MAXWLEN + 1 - (size_t)len);
     hlf_T attr = HLF_COUNT;
-    (void)spell_check(curwin, longword, &attr, NULL, false);
+    spell_check(curwin, longword, &attr, NULL, false);
     if (attr != HLF_COUNT) {
       // Remove this entry.
       xfree(stp[i].st_word);
diff --git a/src/nvim/state.c b/src/nvim/state.c
index d04c131226..a22081ceaa 100644
--- a/src/nvim/state.c
+++ b/src/nvim/state.c
@@ -74,7 +74,7 @@ getkey:
       // Call `os_inchar` directly to block for events or user input without
       // consuming anything from `input_buffer`(os/input.c) or calling the
       // mapping engine.
-      (void)os_inchar(NULL, 0, -1, typebuf.tb_change_cnt, main_loop.events);
+      os_inchar(NULL, 0, -1, typebuf.tb_change_cnt, main_loop.events);
       // If an event was put into the queue, we send K_EVENT directly.
       if (!multiqueue_empty(main_loop.events)) {
         key = K_EVENT;
diff --git a/src/nvim/statusline.c b/src/nvim/statusline.c
index baf5318c76..00c3c9003f 100644
--- a/src/nvim/statusline.c
+++ b/src/nvim/statusline.c
@@ -725,8 +725,6 @@ void draw_tabline(void)
     win_T *cwp;
     int wincount;
     int c;
-    int len;
-    char *p;
     grid_line_start(&default_grid, 0);
     FOR_ALL_TABS(tp) {
       tabcount++;
@@ -782,7 +780,7 @@ void draw_tabline(void)
       if (modified || wincount > 1) {
         if (wincount > 1) {
           vim_snprintf(NameBuff, MAXPATHL, "%d", wincount);
-          len = (int)strlen(NameBuff);
+          int len = (int)strlen(NameBuff);
           if (col + len >= Columns - 3) {
             break;
           }
@@ -801,8 +799,8 @@ void draw_tabline(void)
         // Get buffer name in NameBuff[]
         get_trans_bufname(cwp->w_buffer);
         shorten_dir(NameBuff);
-        len = vim_strsize(NameBuff);
-        p = NameBuff;
+        int len = vim_strsize(NameBuff);
+        char *p = NameBuff;
         while (len > room) {
           len -= ptr2cells(p);
           MB_PTR_ADV(p);
@@ -1399,7 +1397,7 @@ int build_stl_str_hl(win_T *wp, char *out, size_t outlen, char *fmt, OptIndex op
     case STL_VIM_EXPR:     // '{'
     {
       char *block_start = fmt_p - 1;
-      int reevaluate = (*fmt_p == '%');
+      bool reevaluate = (*fmt_p == '%');
       itemisflag = true;
 
       if (reevaluate) {
diff --git a/src/nvim/strings.c b/src/nvim/strings.c
index 9bddc01f02..fab04438b6 100644
--- a/src/nvim/strings.c
+++ b/src/nvim/strings.c
@@ -183,21 +183,17 @@ char *vim_strnsave_unquoted(const char *const string, const size_t length)
 char *vim_strsave_shellescape(const char *string, bool do_special, bool do_newline)
   FUNC_ATTR_NONNULL_RET FUNC_ATTR_MALLOC FUNC_ATTR_NONNULL_ALL
 {
-  char *d;
-  char *escaped_string;
   size_t l;
-  int csh_like;
-  bool fish_like;
 
   // Only csh and similar shells expand '!' within single quotes.  For sh and
   // the like we must not put a backslash before it, it will be taken
   // literally.  If do_special is set the '!' will be escaped twice.
   // Csh also needs to have "\n" escaped twice when do_special is set.
-  csh_like = csh_like_shell();
+  int csh_like = csh_like_shell();
 
   // Fish shell uses '\' as an escape character within single quotes, so '\'
   // itself must be escaped to get a literal '\'.
-  fish_like = fish_like_shell();
+  bool fish_like = fish_like_shell();
 
   // First count the number of extra bytes required.
   size_t length = strlen(string) + 3;       // two quotes and a trailing NUL
@@ -229,8 +225,8 @@ char *vim_strsave_shellescape(const char *string, bool do_special, bool do_newli
   }
 
   // Allocate memory for the result and fill it.
-  escaped_string = xmalloc(length);
-  d = escaped_string;
+  char *escaped_string = xmalloc(length);
+  char *d = escaped_string;
 
   // add opening quote
 #ifdef MSWIN
@@ -301,9 +297,7 @@ char *vim_strsave_shellescape(const char *string, bool do_special, bool do_newli
 char *vim_strsave_up(const char *string)
   FUNC_ATTR_NONNULL_RET FUNC_ATTR_MALLOC FUNC_ATTR_NONNULL_ALL
 {
-  char *p1;
-
-  p1 = xstrdup(string);
+  char *p1 = xstrdup(string);
   vim_strup(p1);
   return p1;
 }
@@ -376,9 +370,7 @@ char *strcase_save(const char *const orig, bool upper)
 void del_trailing_spaces(char *ptr)
   FUNC_ATTR_NONNULL_ALL
 {
-  char *q;
-
-  q = ptr + strlen(ptr);
+  char *q = ptr + strlen(ptr);
   while (--q > ptr && ascii_iswhite(q[0]) && q[-1] != '\\' && q[-1] != Ctrl_V) {
     *q = NUL;
   }
@@ -1360,11 +1352,11 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
     } else {
       size_t min_field_width = 0;
       size_t precision = 0;
-      int zero_padding = 0;
-      int precision_specified = 0;
-      int justify_left = 0;
-      int alternate_form = 0;
-      int force_sign = 0;
+      bool zero_padding = false;
+      bool precision_specified = false;
+      bool justify_left = false;
+      bool alternate_form = false;
+      bool force_sign = false;
 
       // if both ' ' and '+' flags appear, ' ' flag should be ignored
       int space_for_positive = 1;
@@ -1429,17 +1421,17 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
       while (true) {
         switch (*p) {
         case '0':
-          zero_padding = 1; p++; continue;
+          zero_padding = true; p++; continue;
         case '-':
-          justify_left = 1; p++; continue;
+          justify_left = true; p++; continue;
         // if both '0' and '-' flags appear, '0' should be ignored
         case '+':
-          force_sign = 1; space_for_positive = 0; p++; continue;
+          force_sign = true; space_for_positive = 0; p++; continue;
         case ' ':
-          force_sign = 1; p++; continue;
+          force_sign = true; p++; continue;
         // if both ' ' and '+' flags appear, ' ' should be ignored
         case '#':
-          alternate_form = 1; p++; continue;
+          alternate_form = true; p++; continue;
         case '\'':
           p++; continue;
         default:
@@ -1474,7 +1466,7 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
           min_field_width = (size_t)j;
         } else {
           min_field_width = (size_t)-j;
-          justify_left = 1;
+          justify_left = true;
         }
       } else if (ascii_isdigit((int)(*p))) {
         // size_t could be wider than unsigned int; make sure we treat
@@ -1490,7 +1482,7 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
       // parse precision
       if (*p == '.') {
         p++;
-        precision_specified = 1;
+        precision_specified = true;
 
         if (ascii_isdigit((int)(*p))) {
           // size_t could be wider than unsigned int; make sure we
@@ -1525,7 +1517,7 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
           if (j >= 0) {
             precision = (size_t)j;
           } else {
-            precision_specified = 0;
+            precision_specified = false;
             precision = 0;
           }
         }
@@ -1780,7 +1772,7 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
         // '0' flag should be ignored. This is so with Solaris 2.6, Digital
         // UNIX 4.0, HPUX 10, Linux, FreeBSD, NetBSD; but not with Perl.
         if (precision_specified) {
-          zero_padding = 0;
+          zero_padding = false;
         }
 
         if (fmt_spec == 'd') {
@@ -1868,8 +1860,7 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
               && !(zero_padding_insertion_ind < str_arg_l
                    && tmp[zero_padding_insertion_ind] == '0')) {
             // assure leading zero for alternate-form octal numbers
-            if (!precision_specified
-                || precision < num_of_digits + 1) {
+            if (!precision_specified || precision < num_of_digits + 1) {
               // precision is increased to force the first character to be
               // zero, except if a zero value is formatted with an explicit
               // precision of zero
@@ -1926,12 +1917,12 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
                                      force_sign, space_for_positive),
                    sizeof(tmp));
           str_arg_l = strlen(tmp);
-          zero_padding = 0;
+          zero_padding = false;
         } else if (xisnan(f)) {
           // Not a number: nan or NAN
           memmove(tmp, ASCII_ISUPPER(fmt_spec) ? "NAN" : "nan", 4);
           str_arg_l = 3;
-          zero_padding = 0;
+          zero_padding = false;
         } else {
           // Regular float number
           format[0] = '%';
@@ -2017,8 +2008,8 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
 
       default:
         // unrecognized conversion specifier, keep format string as-is
-        zero_padding = 0;  // turn zero padding off for non-numeric conversion
-        justify_left = 1;
+        zero_padding = false;  // turn zero padding off for non-numeric conversion
+        justify_left = true;
         min_field_width = 0;  // reset flags
 
         // discard the unrecognized conversion, just keep
@@ -2229,7 +2220,7 @@ char *strrep(const char *src, const char *what, const char *rep)
 }
 
 /// Implementation of "byteidx()" and "byteidxcomp()" functions
-static void byteidx_common(typval_T *argvars, typval_T *rettv, int comp)
+static void byteidx_common(typval_T *argvars, typval_T *rettv, bool comp)
 {
   rettv->vval.v_number = -1;
 
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index 41c9703f3b..4c74682432 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -340,10 +340,10 @@ void syntax_start(win_T *wp, linenr_T lnum)
   if (VALID_STATE(&current_state)
       && current_lnum < lnum
       && current_lnum < syn_buf->b_ml.ml_line_count) {
-    (void)syn_finish_line(false);
+    syn_finish_line(false);
     if (!current_state_stored) {
       current_lnum++;
-      (void)store_current_state();
+      store_current_state();
     }
 
     // If the current_lnum is now the same as "lnum", keep the current
@@ -401,7 +401,7 @@ void syntax_start(win_T *wp, linenr_T lnum)
   }
   while (current_lnum < lnum) {
     syn_start_line();
-    (void)syn_finish_line(false);
+    syn_finish_line(false);
     current_lnum++;
 
     // If we parsed at least "minlines" lines or started at a valid
@@ -490,23 +490,16 @@ static void clear_current_state(void)
 // 3. Simply start on a given number of lines above "lnum".
 static void syn_sync(win_T *wp, linenr_T start_lnum, synstate_T *last_valid)
 {
-  buf_T *curbuf_save;
-  win_T *curwin_save;
   pos_T cursor_save;
-  int idx;
   linenr_T lnum;
-  linenr_T end_lnum;
   linenr_T break_lnum;
-  bool had_sync_point;
   stateitem_T *cur_si;
   synpat_T *spp;
-  char *line;
   int found_flags = 0;
   int found_match_idx = 0;
   linenr_T found_current_lnum = 0;
   int found_current_col = 0;
   lpos_T found_m_endpos;
-  colnr_T prev_current_col;
 
   // Clear any current state that might be hanging around.
   invalidate_current_state();
@@ -543,14 +536,14 @@ static void syn_sync(win_T *wp, linenr_T start_lnum, synstate_T *last_valid)
   if (syn_block->b_syn_sync_flags & SF_CCOMMENT) {
     // Need to make syn_buf the current buffer for a moment, to be able to
     // use find_start_comment().
-    curwin_save = curwin;
+    win_T *curwin_save = curwin;
     curwin = wp;
-    curbuf_save = curbuf;
+    buf_T *curbuf_save = curbuf;
     curbuf = syn_buf;
 
     // Skip lines that end in a backslash.
     for (; start_lnum > 1; start_lnum--) {
-      line = ml_get(start_lnum - 1);
+      char *line = ml_get(start_lnum - 1);
       if (*line == NUL || *(line + strlen(line) - 1) != '\\') {
         break;
       }
@@ -566,7 +559,7 @@ static void syn_sync(win_T *wp, linenr_T start_lnum, synstate_T *last_valid)
     // defines the comment.
     // Restrict the search for the end of a comment to b_syn_sync_maxlines.
     if (find_start_comment((int)syn_block->b_syn_sync_maxlines) != NULL) {
-      for (idx = syn_block->b_syn_patterns.ga_len; --idx >= 0;) {
+      for (int idx = syn_block->b_syn_patterns.ga_len; --idx >= 0;) {
         if (SYN_ITEMS(syn_block)[idx].sp_syn.id
             == syn_block->b_syn_sync_id
             && SYN_ITEMS(syn_block)[idx].sp_type == SPTYPE_START) {
@@ -593,7 +586,7 @@ static void syn_sync(win_T *wp, linenr_T start_lnum, synstate_T *last_valid)
 
     found_m_endpos.lnum = 0;
     found_m_endpos.col = 0;
-    end_lnum = start_lnum;
+    linenr_T end_lnum = start_lnum;
     lnum = start_lnum;
     while (--lnum > break_lnum) {
       // This can take a long time: break when CTRL-C pressed.
@@ -621,7 +614,7 @@ static void syn_sync(win_T *wp, linenr_T start_lnum, synstate_T *last_valid)
       for (current_lnum = lnum; current_lnum < end_lnum; current_lnum++) {
         syn_start_line();
         while (true) {
-          had_sync_point = syn_finish_line(true);
+          bool had_sync_point = syn_finish_line(true);
           // When a sync point has been found, remember where, and
           // continue to look for another one, further on in the line.
           if (had_sync_point && current_state.ga_len) {
@@ -660,7 +653,7 @@ static void syn_sync(win_T *wp, linenr_T start_lnum, synstate_T *last_valid)
             // syn_current_attr() will have skipped the check for
             // an item that ends here, need to do that now.  Be
             // careful not to go past the NUL.
-            prev_current_col = current_col;
+            colnr_T prev_current_col = current_col;
             if (syn_getcurline()[current_col] != NUL) {
               current_col++;
             }
@@ -697,7 +690,7 @@ static void syn_sync(win_T *wp, linenr_T start_lnum, synstate_T *last_valid)
           }
           current_col = found_m_endpos.col;
           current_lnum = found_m_endpos.lnum;
-          (void)syn_finish_line(false);
+          syn_finish_line(false);
           current_lnum++;
         } else {
           current_lnum = start_lnum;
@@ -1149,7 +1142,7 @@ static synstate_T *store_current_state(void)
     // Add a new entry
     // If no free items, cleanup the array first.
     if (syn_block->b_sst_freecount == 0) {
-      (void)syn_stack_cleanup();
+      syn_stack_cleanup();
       // "sp" may have been moved to the freelist now
       sp = syn_stack_find_entry(current_lnum);
     }
@@ -1369,7 +1362,7 @@ bool syntax_check_changed(linenr_T lnum)
     if (sp != NULL && sp->sst_lnum == lnum) {
       // finish the previous line (needed when not all of the line was
       // drawn)
-      (void)syn_finish_line(false);
+      syn_finish_line(false);
 
       // Compare the current state with the previously saved state of
       // the line.
@@ -1379,7 +1372,7 @@ bool syntax_check_changed(linenr_T lnum)
 
       // Store the current state in b_sst_array[] for later use.
       current_lnum++;
-      (void)store_current_state();
+      store_current_state();
     }
   }
 
@@ -1395,7 +1388,7 @@ bool syntax_check_changed(linenr_T lnum)
 static bool syn_finish_line(const bool syncing)
 {
   while (!current_finished) {
-    (void)syn_current_attr(syncing, false, NULL, false);
+    syn_current_attr(syncing, false, NULL, false);
 
     // When syncing, and found some item, need to check the item.
     if (syncing && current_state.ga_len) {
@@ -1518,7 +1511,7 @@ static int syn_current_attr(const bool syncing, const bool displaying, bool *con
     // If we found a match after the last column, use it.
     if (next_match_idx >= 0 && next_match_col >= (int)current_col
         && next_match_col != MAXCOL) {
-      (void)push_next_match();
+      push_next_match();
     }
 
     current_finished = true;
@@ -2416,8 +2409,8 @@ static void find_endpos(int idx, lpos_T *startpos, lpos_T *m_endpos, lpos_T *hl_
 
       regmatch.rmm_ic = spp->sp_ic;
       regmatch.regprog = spp->sp_prog;
-      int r = syn_regexec(&regmatch, startpos->lnum, lc_col,
-                          IF_SYN_TIME(&spp->sp_time));
+      bool r = syn_regexec(&regmatch, startpos->lnum, lc_col,
+                           IF_SYN_TIME(&spp->sp_time));
       spp->sp_prog = regmatch.regprog;
       if (r) {
         if (best_idx == -1 || regmatch.startpos[0].col
@@ -2663,7 +2656,7 @@ static char *syn_getcurline(void)
 
 // Call vim_regexec() to find a match with "rmp" in "syn_buf".
 // Returns true when there is a match.
-static int syn_regexec(regmmatch_T *rmp, linenr_T lnum, colnr_T col, syn_time_T *st)
+static bool syn_regexec(regmmatch_T *rmp, linenr_T lnum, colnr_T col, syn_time_T *st)
 {
   int timed_out = 0;
   proftime_T pt;
@@ -3367,7 +3360,7 @@ static void syn_list_one(const int id, const bool syncing, const bool link_only)
       continue;
     }
 
-    (void)syn_list_header(did_header, 0, id, true);
+    syn_list_header(did_header, 0, id, true);
     did_header = true;
     last_matchgroup = 0;
     if (spp->sp_type == SPTYPE_MATCH) {
@@ -3420,7 +3413,7 @@ static void syn_list_one(const int id, const bool syncing, const bool link_only)
 
   // list the link, if there is one
   if (highlight_link_id(id - 1) && (did_header || link_only) && !got_int) {
-    (void)syn_list_header(did_header, 0, id, true);
+    syn_list_header(did_header, 0, id, true);
     msg_puts_attr("links to", attr);
     msg_putchar(' ');
     msg_outtrans(highlight_group_name(highlight_link_id(id - 1) - 1), 0);
@@ -3642,23 +3635,17 @@ static bool syn_list_keywords(const int id, const hashtab_T *const ht, bool did_
 
 static void syn_clear_keyword(int id, hashtab_T *ht)
 {
-  hashitem_T *hi;
-  keyentry_T *kp;
-  keyentry_T *kp_prev;
-  keyentry_T *kp_next;
-  int todo;
-
   hash_lock(ht);
-  todo = (int)ht->ht_used;
-  for (hi = ht->ht_array; todo > 0; hi++) {
+  int todo = (int)ht->ht_used;
+  for (hashitem_T *hi = ht->ht_array; todo > 0; hi++) {
     if (HASHITEM_EMPTY(hi)) {
       continue;
     }
     todo--;
-    kp_prev = NULL;
-    for (kp = HI2KE(hi); kp != NULL;) {
+    keyentry_T *kp_prev = NULL;
+    for (keyentry_T *kp = HI2KE(hi); kp != NULL;) {
       if (kp->k_syn.id == id) {
-        kp_next = kp->ke_next;
+        keyentry_T *kp_next = kp->ke_next;
         if (kp_prev == NULL) {
           if (kp_next == NULL) {
             hash_remove(ht, hi);
@@ -3684,16 +3671,13 @@ static void syn_clear_keyword(int id, hashtab_T *ht)
 // Clear a whole keyword table.
 static void clear_keywtab(hashtab_T *ht)
 {
-  hashitem_T *hi;
-  int todo;
-  keyentry_T *kp;
   keyentry_T *kp_next;
 
-  todo = (int)ht->ht_used;
-  for (hi = ht->ht_array; todo > 0; hi++) {
+  int todo = (int)ht->ht_used;
+  for (hashitem_T *hi = ht->ht_array; todo > 0; hi++) {
     if (!HASHITEM_EMPTY(hi)) {
       todo--;
-      for (kp = HI2KE(hi); kp != NULL; kp = kp_next) {
+      for (keyentry_T *kp = HI2KE(hi); kp != NULL; kp = kp_next) {
         kp_next = kp->ke_next;
         xfree(kp->next_list);
         xfree(kp->k_syn.cont_in_list);
@@ -3789,9 +3773,7 @@ static char *get_group_name(char *arg, char **name_end)
 ///              Return NULL for any error;
 static char *get_syn_options(char *arg, syn_opt_arg_T *opt, int *conceal_char, int skip)
 {
-  int syn_id;
   int len = 0;
-  char *p;
   int fidx;
   static const struct flag {
     char *name;
@@ -3835,7 +3817,7 @@ static char *get_syn_options(char *arg, syn_opt_arg_T *opt, int *conceal_char, i
     }
 
     for (fidx = ARRAY_SIZE(flagtab); --fidx >= 0;) {
-      p = flagtab[fidx].name;
+      char *p = flagtab[fidx].name;
       int i;
       for (i = 0, len = 0; p[i] != NUL; i += 2, len++) {
         if (arg[len] != p[i] && arg[len] != p[i + 1]) {
@@ -3904,7 +3886,7 @@ static char *get_syn_options(char *arg, syn_opt_arg_T *opt, int *conceal_char, i
         if (strcmp(gname, "NONE") == 0) {
           *opt->sync_idx = NONE_IDX;
         } else {
-          syn_id = syn_name2id(gname);
+          int syn_id = syn_name2id(gname);
           int i;
           for (i = curwin->w_s->b_syn_patterns.ga_len; --i >= 0;) {
             if (SYN_ITEMS(curwin->w_s)[i].sp_syn.id == syn_id
@@ -3960,10 +3942,7 @@ static void syn_cmd_include(exarg_T *eap, int syncing)
   char *arg = eap->arg;
   int sgl_id = 1;
   char *group_name_end;
-  char *rest;
   const char *errormsg = NULL;
-  int prev_toplvl_grp;
-  int prev_syn_inc_tag;
   bool source = false;
 
   eap->nextcmd = find_nextcmd(arg);
@@ -3973,7 +3952,7 @@ static void syn_cmd_include(exarg_T *eap, int syncing)
 
   if (arg[0] == '@') {
     arg++;
-    rest = get_group_name(arg, &group_name_end);
+    char *rest = get_group_name(arg, &group_name_end);
     if (rest == NULL) {
       emsg(_("E397: Filename required"));
       return;
@@ -4009,9 +3988,9 @@ static void syn_cmd_include(exarg_T *eap, int syncing)
     emsg(_("E847: Too many syntax includes"));
     return;
   }
-  prev_syn_inc_tag = current_syn_inc_tag;
+  int prev_syn_inc_tag = current_syn_inc_tag;
   current_syn_inc_tag = ++running_syn_inc_tag;
-  prev_toplvl_grp = curwin->w_s->b_syn_topgrp;
+  int prev_toplvl_grp = curwin->w_s->b_syn_topgrp;
   curwin->w_s->b_syn_topgrp = sgl_id;
   if (source
       ? do_source(eap->arg, false, DOSO_NONE, NULL) == FAIL
@@ -4028,15 +4007,11 @@ static void syn_cmd_keyword(exarg_T *eap, int syncing)
   char *arg = eap->arg;
   char *group_name_end;
   int syn_id;
-  char *rest;
   char *keyword_copy = NULL;
-  char *p;
-  char *kw;
   syn_opt_arg_T syn_opt_arg;
-  int cnt;
   int conceal_char = NUL;
 
-  rest = get_group_name(arg, &group_name_end);
+  char *rest = get_group_name(arg, &group_name_end);
 
   if (rest != NULL) {
     if (eap->skip) {
@@ -4059,8 +4034,8 @@ static void syn_cmd_keyword(exarg_T *eap, int syncing)
       // The options given apply to ALL keywords, so all options must be
       // found before keywords can be created.
       // 1: collect the options and copy the keywords to keyword_copy.
-      cnt = 0;
-      p = keyword_copy;
+      int cnt = 0;
+      char *p = keyword_copy;
       for (; rest != NULL && !ends_excmd(*rest); rest = skipwhite(rest)) {
         rest = get_syn_options(rest, &syn_opt_arg, &conceal_char, eap->skip);
         if (rest == NULL || ends_excmd(*rest)) {
@@ -4082,7 +4057,7 @@ static void syn_cmd_keyword(exarg_T *eap, int syncing)
         syn_incl_toplevel(syn_id, &syn_opt_arg.flags);
 
         // 2: Add an entry for each keyword.
-        for (kw = keyword_copy; --cnt >= 0; kw += strlen(kw) + 1) {
+        for (char *kw = keyword_copy; --cnt >= 0; kw += strlen(kw) + 1) {
           for (p = vim_strchr(kw, '[');;) {
             if (p != NULL) {
               *p = NUL;
@@ -4233,7 +4208,6 @@ static void syn_cmd_region(exarg_T *eap, int syncing)
   char *rest;                    // next arg, NULL on error
   char *key_end;
   char *key = NULL;
-  char *p;
   int item;
 #define ITEM_START          0
 #define ITEM_SKIP           1
@@ -4316,7 +4290,7 @@ static void syn_cmd_region(exarg_T *eap, int syncing)
     }
 
     if (item == ITEM_MATCHGROUP) {
-      p = skiptowhite(rest);
+      char *p = skiptowhite(rest);
       if ((p - rest == 4 && strncmp(rest, "NONE", 4) == 0) || eap->skip) {
         matchgroup_id = 0;
       } else {
@@ -4643,7 +4617,6 @@ static void syn_cmd_cluster(exarg_T *eap, int syncing)
 {
   char *arg = eap->arg;
   char *group_name_end;
-  char *rest;
   bool got_clstr = false;
   int opt_len;
   int list_op;
@@ -4653,7 +4626,7 @@ static void syn_cmd_cluster(exarg_T *eap, int syncing)
     return;
   }
 
-  rest = get_group_name(arg, &group_name_end);
+  char *rest = get_group_name(arg, &group_name_end);
 
   if (rest != NULL) {
     int scl_id = syn_check_cluster(arg, (int)(group_name_end - arg));
@@ -4720,7 +4693,6 @@ static void init_syn_patterns(void)
 /// @return  a pointer to the next argument, or NULL in case of an error.
 static char *get_syn_pattern(char *arg, synpat_T *ci)
 {
-  int *p;
   int idx;
 
   // need at least three chars
@@ -4757,7 +4729,7 @@ static char *get_syn_pattern(char *arg, synpat_T *ci)
       }
     }
     if (idx >= 0) {
-      p = &(ci->sp_offsets[idx]);
+      int *p = &(ci->sp_offsets[idx]);
       if (idx != SPO_LC_OFF) {
         switch (end[3]) {
         case 's':
@@ -5123,10 +5095,8 @@ static int16_t *copy_id_list(const int16_t *const list)
 static int in_id_list(stateitem_T *cur_si, int16_t *list, struct sp_syn *ssp, int contained)
 {
   int retval;
-  int16_t *scl_list;
   int16_t id = ssp->id;
   static int depth = 0;
-  int r;
 
   // If ssp has a "containedin" list and "cur_si" is in it, return true.
   if (cur_si != NULL && ssp->cont_in_list != NULL
@@ -5189,12 +5159,12 @@ static int in_id_list(stateitem_T *cur_si, int16_t *list, struct sp_syn *ssp, in
       return retval;
     }
     if (item >= SYNID_CLUSTER) {
-      scl_list = SYN_CLSTR(syn_block)[item - SYNID_CLUSTER].scl_list;
+      int16_t *scl_list = SYN_CLSTR(syn_block)[item - SYNID_CLUSTER].scl_list;
       // restrict recursiveness to 30 to avoid an endless loop for a
       // cluster that includes itself (indirectly)
       if (scl_list != NULL && depth < 30) {
         depth++;
-        r = in_id_list(NULL, scl_list, ssp, contained);
+        int r = in_id_list(NULL, scl_list, ssp, contained);
         depth--;
         if (r) {
           return retval;
@@ -5437,7 +5407,7 @@ int syn_get_id(win_T *wp, linenr_T lnum, colnr_T col, int trans, bool *spellp, i
     next_match_idx = -1;
   }
 
-  (void)get_syntax_attr(col, spellp, keep_state);
+  get_syntax_attr(col, spellp, keep_state);
 
   return trans ? current_trans_id : current_id;
 }
@@ -5459,7 +5429,7 @@ int syn_get_concealed_id(win_T *wp, linenr_T lnum, colnr_T col)
 {
   int seqnr;
 
-  (void)syn_get_id(wp, lnum, col, false, NULL, false);
+  syn_get_id(wp, lnum, col, false, NULL, false);
   int syntax_flags = get_syntax_info(&seqnr);
 
   if (syntax_flags & HL_CONCEAL) {
@@ -5519,7 +5489,7 @@ int syn_get_foldlevel(win_T *wp, linenr_T lnum)
       int cur_level = level;
       int low_level = cur_level;
       while (!current_finished) {
-        (void)syn_current_attr(false, false, NULL, false);
+        syn_current_attr(false, false, NULL, false);
         cur_level = syn_cur_foldlevel();
         if (cur_level < low_level) {
           low_level = cur_level;
diff --git a/src/nvim/tag.c b/src/nvim/tag.c
index 8c7b6171aa..01f9eb0141 100644
--- a/src/nvim/tag.c
+++ b/src/nvim/tag.c
@@ -279,7 +279,7 @@ void set_buflocal_tfu_callback(buf_T *buf)
 /// @param tag  tag (pattern) to jump to
 /// @param forceit  :ta with !
 /// @param verbose  print "tag not found" message
-void do_tag(char *tag, int type, int count, int forceit, int verbose)
+void do_tag(char *tag, int type, int count, int forceit, bool verbose)
 {
   taggy_T *tagstack = curwin->w_tagstack;
   int tagstackidx = curwin->w_tagstackidx;
@@ -546,7 +546,6 @@ void do_tag(char *tag, int type, int count, int forceit, int verbose)
 
   // Repeat searching for tags, when a file has not been found.
   while (true) {
-    int other_name;
     char *name;
 
     // When desired match not found yet, try to find it (and others).
@@ -560,7 +559,7 @@ void do_tag(char *tag, int type, int count, int forceit, int verbose)
     } else {
       name = tag;
     }
-    other_name = (tagmatchname == NULL || strcmp(tagmatchname, name) != 0);
+    bool other_name = (tagmatchname == NULL || strcmp(tagmatchname, name) != 0);
     if (new_tag
         || (cur_match >= num_matches && max_num_matches != MAXCOL)
         || other_name) {
@@ -717,7 +716,7 @@ void do_tag(char *tag, int type, int count, int forceit, int verbose)
         smsg(0, _("File \"%s\" does not exist"), nofile_fname);
       }
 
-      int ic = (matches[cur_match][0] & MT_IC_OFF);
+      bool ic = (matches[cur_match][0] & MT_IC_OFF);
       if (type != DT_TAG && type != DT_SELECT && type != DT_JUMP
           && (num_matches > 1 || ic)
           && !skip_msg) {
@@ -1160,7 +1159,7 @@ static int tag_strnicmp(char *s1, char *s2, size_t len)
 }
 
 // Extract info from the tag search pattern "pats->pat".
-static void prepare_pats(pat_T *pats, int has_re)
+static void prepare_pats(pat_T *pats, bool has_re)
 {
   pats->head = pats->pat;
   pats->headlen = pats->len;
@@ -1275,7 +1274,7 @@ static int find_tagfunc_tags(char *pat, garray_T *ga, int *match_count, int flag
     char *res_fname;
     char *res_cmd;
     char *res_kind;
-    int has_extra = 0;
+    bool has_extra = false;
     int name_only = flags & TAG_NAMES;
 
     if (TV_LIST_ITEM_TV(li)->v_type != VAR_DICT) {
@@ -1310,7 +1309,7 @@ static int find_tagfunc_tags(char *pat, garray_T *ga, int *match_count, int flag
         res_cmd = tv->vval.v_string;
         continue;
       }
-      has_extra = 1;
+      has_extra = true;
       if (!strcmp(dict_key, "kind")) {
         res_kind = tv->vval.v_string;
         continue;
@@ -1530,7 +1529,7 @@ static int findtags_apply_tfu(findtags_state_T *st, char *pat, char *buf_ffname)
 /// reached end of a emacs included tags file)
 static tags_read_status_T findtags_get_next_line(findtags_state_T *st, tagsearch_info_T *sinfo_p)
 {
-  int eof;
+  bool eof;
 
   // For binary search: compute the next offset to use.
   if (st->state == TS_BINARY) {
@@ -1545,7 +1544,7 @@ static tags_read_status_T findtags_get_next_line(findtags_state_T *st, tagsearch
     sinfo_p->curr_offset -= st->lbuf_size * 2;
     if (sinfo_p->curr_offset < 0) {
       sinfo_p->curr_offset = 0;
-      (void)fseek(st->fp, 0, SEEK_SET);
+      fseek(st->fp, 0, SEEK_SET);
       st->state = TS_STEP_FORWARD;
     }
   }
@@ -2304,7 +2303,7 @@ int find_tags(char *pat, int *num_matches, char ***matchesp, int flags, int minc
   char *saved_pat = NULL;                // copy of pat[]
 
   int findall = (mincount == MAXCOL || mincount == TAG_MANY);  // find all matching tags
-  int has_re = (flags & TAG_REGEXP);            // regexp used
+  bool has_re = (flags & TAG_REGEXP);            // regexp used
   int noic = (flags & TAG_NOIC);
   int verbose = (flags & TAG_VERBOSE);
   int save_p_ic = p_ic;
@@ -2564,7 +2563,7 @@ int get_tagfname(tagname_T *tnp, int first, char *buf)
 
       // Copy next file name into buf.
       buf[0] = NUL;
-      (void)copy_option_part(&tnp->tn_np, buf, MAXPATHL - 1, " ,");
+      copy_option_part(&tnp->tn_np, buf, MAXPATHL - 1, " ,");
 
       char *r_ptr = vim_findfile_stopdir(buf);
       // move the filename one char forward and truncate the
@@ -2774,7 +2773,7 @@ static char *tag_full_fname(tagptrs_T *tagp)
 /// @param keep_help  keep help flag
 ///
 /// @return  OK for success, NOTAGFILE when file not found, FAIL otherwise.
-static int jumpto_tag(const char *lbuf_arg, int forceit, int keep_help)
+static int jumpto_tag(const char *lbuf_arg, int forceit, bool keep_help)
 {
   char *pbuf_end;
   char *tofree_fname = NULL;
@@ -2947,11 +2946,10 @@ static int jumpto_tag(const char *lbuf_arg, int forceit, int keep_help)
 
         // try again, ignore case now
         p_ic = true;
-        if (!do_search(NULL, pbuf[0], pbuf[0], pbuf + 1, 1,
-                       search_options, NULL)) {
+        if (!do_search(NULL, pbuf[0], pbuf[0], pbuf + 1, 1, search_options, NULL)) {
           // Failed to find pattern, take a guess: "^func  ("
           found = 2;
-          (void)test_for_static(&tagp);
+          test_for_static(&tagp);
           char cc = *tagp.tagname_end;
           *tagp.tagname_end = NUL;
           snprintf(pbuf, LSIZE, "^%s\\s\\*(", tagp.tagname);
@@ -3171,7 +3169,7 @@ static void tagstack_clear_entry(taggy_T *item)
 }
 
 /// @param tagnames  expand tag names
-int expand_tags(int tagnames, char *pat, int *num_file, char ***file)
+int expand_tags(bool tagnames, char *pat, int *num_file, char ***file)
 {
   int extra_flag;
   size_t name_buf_size = 100;
@@ -3203,10 +3201,8 @@ int expand_tags(int tagnames, char *pat, int *num_file, char ***file)
       parse_match((*file)[i], &t_p);
       len = (size_t)(t_p.tagname_end - t_p.tagname);
       if (len > name_buf_size - 3) {
-        char *buf;
-
         name_buf_size = len + 3;
-        buf = xrealloc(name_buf, name_buf_size);
+        char *buf = xrealloc(name_buf, name_buf_size);
         name_buf = buf;
       }
 
@@ -3317,12 +3313,11 @@ int get_tags(list_T *list, char *pat, char *buf_fname)
           // skip "file:" (static tag)
           p += 4;
         } else if (!ascii_iswhite(*p)) {
-          char *n;
           int len;
 
           // Add extra field as a dict entry.  Fields are
           // separated by Tabs.
-          n = p;
+          char *n = p;
           while (*p != NUL && *p >= ' ' && *p < 127 && *p != ':') {
             p++;
           }
diff --git a/src/nvim/textformat.c b/src/nvim/textformat.c
index 7803322439..509a88e441 100644
--- a/src/nvim/textformat.c
+++ b/src/nvim/textformat.c
@@ -77,7 +77,7 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
   bool first_line = true;
   colnr_T leader_len;
   bool no_leader = false;
-  int do_comments = (flags & INSCHAR_DO_COM);
+  bool do_comments = (flags & INSCHAR_DO_COM);
   int has_lbr = curwin->w_p_lbr;
 
   // make sure win_lbr_chartabsize() counts correctly
@@ -100,15 +100,12 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
     int wantcol;                        // column at textwidth border
     int foundcol;                       // column for start of spaces
     int end_foundcol = 0;               // column for start of word
-    colnr_T virtcol;
     int orig_col = 0;
     char *saved_text = NULL;
     colnr_T col;
-    colnr_T end_col;
     bool did_do_comment = false;
 
-    virtcol = get_nolist_virtcol()
-              + char2cells(c != NUL ? c : gchar_cursor());
+    colnr_T virtcol = get_nolist_virtcol() + char2cells(c != NUL ? c : gchar_cursor());
     if (virtcol <= (colnr_T)textwidth) {
       break;
     }
@@ -175,7 +172,7 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
       }
       if (WHITECHAR(cc)) {
         // remember position of blank just before text
-        end_col = curwin->w_cursor.col;
+        colnr_T end_col = curwin->w_cursor.col;
 
         // find start of sequence of blanks
         int wcc = 0;  // counter for whitespace chars
@@ -419,7 +416,7 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
               ins_str(" ");
             }
           } else {
-            (void)set_indent(second_indent, SIN_CHANGED);
+            set_indent(second_indent, SIN_CHANGED);
           }
         }
       }
@@ -472,9 +469,7 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
 static int fmt_check_par(linenr_T lnum, int *leader_len, char **leader_flags, bool do_comments)
 {
   char *flags = NULL;        // init for GCC
-  char *ptr;
-
-  ptr = ml_get(lnum);
+  char *ptr = ml_get(lnum);
   if (do_comments) {
     *leader_len = get_leader_len(ptr, leader_flags, false, true);
   } else {
@@ -624,8 +619,6 @@ static bool paragraph_start(linenr_T lnum)
 /// @param prev_line   may start in previous line
 void auto_format(bool trailblank, bool prev_line)
 {
-  char *linep;
-
   if (!has_format_option(FO_AUTO)) {
     return;
   }
@@ -694,7 +687,7 @@ void auto_format(bool trailblank, bool prev_line)
   // need to add a space when 'w' is in 'formatoptions' to keep a paragraph
   // formatted.
   if (!wasatend && has_format_option(FO_WHITE_PAR)) {
-    linep = get_cursor_line_ptr();
+    char *linep = get_cursor_line_ptr();
     colnr_T len = (colnr_T)strlen(linep);
     if (curwin->w_cursor.col == len) {
       char *plinep = xstrnsave(linep, (size_t)len + 2);
@@ -1052,7 +1045,7 @@ void format_lines(linenr_T line_count, bool avoid_fex)
               indent = get_indent();
             }
           }
-          (void)set_indent(indent, SIN_CHANGED);
+          set_indent(indent, SIN_CHANGED);
         }
 
         // put cursor on last non-space
@@ -1096,13 +1089,13 @@ void format_lines(linenr_T line_count, bool avoid_fex)
           break;
         }
         if (next_leader_len > 0) {
-          (void)del_bytes(next_leader_len, false, false);
+          del_bytes(next_leader_len, false, false);
           mark_col_adjust(curwin->w_cursor.lnum, 0, 0, -next_leader_len, 0);
         } else if (second_indent > 0) {   // the "leader" for FO_Q_SECOND
           int indent = (int)getwhitecols_curline();
 
           if (indent > 0) {
-            (void)del_bytes(indent, false, false);
+            del_bytes(indent, false, false);
             mark_col_adjust(curwin->w_cursor.lnum, 0, 0, -indent, 0);
           }
         }
diff --git a/src/nvim/textobject.c b/src/nvim/textobject.c
index 2d1fd8c699..3d8e7c9901 100644
--- a/src/nvim/textobject.c
+++ b/src/nvim/textobject.c
@@ -169,14 +169,13 @@ found:
 /// @return       true if the next paragraph or section was found.
 bool findpar(bool *pincl, int dir, int count, int what, bool both)
 {
-  linenr_T curr;
   bool first;               // true on first line
   linenr_T fold_first;      // first line of a closed fold
   linenr_T fold_last;       // last line of a closed fold
   bool fold_skipped;        // true if a closed fold was skipped this
                             // iteration
 
-  curr = curwin->w_cursor.lnum;
+  linenr_T curr = curwin->w_cursor.lnum;
 
   while (count--) {
     bool did_skip = false;  // true after separating lines have been skipped
@@ -259,9 +258,7 @@ static bool inmacro(char *opt, const char *s)
 /// If 'both' is true also stop at '}'
 bool startPS(linenr_T lnum, int para, bool both)
 {
-  char *s;
-
-  s = ml_get(lnum);
+  char *s = ml_get(lnum);
   if ((uint8_t)(*s) == para || *s == '\f' || (both && *s == '}')) {
     return true;
   }
@@ -293,9 +290,7 @@ static bool cls_bigword;  ///< true for "W", "B" or "E"
 /// boundaries are of interest.
 static int cls(void)
 {
-  int c;
-
-  c = gchar_cursor();
+  int c = gchar_cursor();
   if (c == ' ' || c == '\t' || c == NUL) {
     return 0;
   }
@@ -534,9 +529,7 @@ static bool skip_chars(int cclass, int dir)
 /// Go back to the start of the word or the start of white space
 static void back_in_line(void)
 {
-  int sclass;                       // starting class
-
-  sclass = cls();
+  int sclass = cls();  // starting class
   while (true) {
     if (curwin->w_cursor.col == 0) {        // stop at start of line
       break;
@@ -723,15 +716,13 @@ int current_word(oparg_T *oap, int count, bool include, bool bigword)
 /// When Visual active, extend it by one or more sentences.
 int current_sent(oparg_T *oap, int count, bool include)
 {
-  pos_T start_pos;
-  pos_T pos;
   bool start_blank;
   int c;
   bool at_start_sent;
   int ncount;
 
-  start_pos = curwin->w_cursor;
-  pos = start_pos;
+  pos_T start_pos = curwin->w_cursor;
+  pos_T pos = start_pos;
   findsent(FORWARD, 1);        // Find start of next sentence.
 
   // When the Visual area is bigger than one character: Extend it.
@@ -1314,7 +1305,7 @@ extend:
   }
 
   // First move back to the start_lnum of the paragraph or white lines
-  int white_in_front = linewhite(start_lnum);
+  bool white_in_front = linewhite(start_lnum);
   while (start_lnum > 1) {
     if (white_in_front) {           // stop at first white line
       if (!linewhite(start_lnum - 1)) {
diff --git a/src/nvim/undo.c b/src/nvim/undo.c
index 2d631f237f..df38b3cb02 100644
--- a/src/nvim/undo.c
+++ b/src/nvim/undo.c
@@ -344,7 +344,7 @@ static inline void zero_fmark_additional_data(fmark_T *fmarks)
 /// "reload" is true when saving for a buffer reload.
 /// Careful: may trigger autocommands that reload the buffer.
 /// Returns FAIL when lines could not be saved, OK otherwise.
-int u_savecommon(buf_T *buf, linenr_T top, linenr_T bot, linenr_T newbot, int reload)
+int u_savecommon(buf_T *buf, linenr_T top, linenr_T bot, linenr_T newbot, bool reload)
 {
   if (!reload) {
     // When making changes is not allowed return FAIL.  It's a crude way
@@ -934,7 +934,7 @@ static u_header_T *unserialize_uhp(bufinfo_T *bi, const char *file_name)
     default:
       // Field not supported, skip it.
       while (--len >= 0) {
-        (void)undo_read_byte(bi);
+        undo_read_byte(bi);
       }
     }
   }
@@ -1255,7 +1255,7 @@ void u_write_undo(const char *const name, const bool forceit, buf_T *const buf,
     semsg(_(e_not_open), file_name);
     goto theend;
   }
-  (void)os_setperm(file_name, perm);
+  os_setperm(file_name, perm);
   if (p_verbose > 0) {
     verbose_enter();
     smsg(0, _("Writing undo file: %s"), file_name);
@@ -1500,7 +1500,7 @@ void u_read_undo(char *name, const uint8_t *hash, const char *orig_name FUNC_ATT
     default:
       // field not supported, skip
       while (--len >= 0) {
-        (void)undo_read_byte(&bi);
+        undo_read_byte(&bi);
       }
     }
   }
@@ -2250,7 +2250,7 @@ target_zero:
 ///
 /// @param undo If `true`, go up the tree. Down if `false`.
 /// @param do_buf_event If `true`, send buffer updates.
-static void u_undoredo(int undo, bool do_buf_event)
+static void u_undoredo(bool undo, bool do_buf_event)
 {
   char **newarray = NULL;
   linenr_T newlnum = MAXLNUM;
diff --git a/src/nvim/usercmd.c b/src/nvim/usercmd.c
index 148620865a..30f31d5bd9 100644
--- a/src/nvim/usercmd.c
+++ b/src/nvim/usercmd.c
@@ -1708,8 +1708,8 @@ int do_ucmd(exarg_T *eap, bool preview)
     save_current_sctx = current_sctx;
     current_sctx.sc_sid = cmd->uc_script_ctx.sc_sid;
   }
-  (void)do_cmdline(buf, eap->getline, eap->cookie,
-                   DOCMD_VERBOSE|DOCMD_NOWAIT|DOCMD_KEYTYPED);
+  do_cmdline(buf, eap->getline, eap->cookie,
+             DOCMD_VERBOSE|DOCMD_NOWAIT|DOCMD_KEYTYPED);
 
   // Careful: Do not use "cmd" here, it may have become invalid if a user
   // command was added.
diff --git a/src/nvim/version.c b/src/nvim/version.c
index ed9f270b5d..5da35a9724 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -2580,7 +2580,7 @@ void ex_version(exarg_T *eap)
 /// When "wrap" is true wrap the string in [].
 /// @param s
 /// @param wrap
-static void version_msg_wrap(char *s, int wrap)
+static void version_msg_wrap(char *s, bool wrap)
 {
   int len = vim_strsize(s) + (wrap ? 2 : 0);
 
@@ -2647,7 +2647,7 @@ void list_in_columns(char **items, int size, int current)
   for (int i = 0; !got_int && i < nrow * ncol; i++) {
     int idx = (i / ncol) + (i % ncol) * nrow;
     if (idx < item_count) {
-      int last_col = (i + 1) % ncol == 0;
+      bool last_col = (i + 1) % ncol == 0;
       if (idx == current) {
         msg_putchar('[');
       }
diff --git a/src/nvim/window.c b/src/nvim/window.c
index d928063b2f..bb630f6217 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -190,7 +190,7 @@ void do_window(int nchar, int Prenum, int xchar)
     if (bt_quickfix(curbuf)) {
       goto newwindow;
     }
-    (void)win_split(Prenum, 0);
+    win_split(Prenum, 0);
     break;
 
   // split current window in two parts, vertically
@@ -203,7 +203,7 @@ void do_window(int nchar, int Prenum, int xchar)
     if (bt_quickfix(curbuf)) {
       goto newwindow;
     }
-    (void)win_split(Prenum, WSP_VERT);
+    win_split(Prenum, WSP_VERT);
     break;
 
   // split current window and edit alternate file
@@ -222,8 +222,8 @@ void do_window(int nchar, int Prenum, int xchar)
     }
 
     if (!curbuf_locked() && win_split(0, 0) == OK) {
-      (void)buflist_getfile(Prenum == 0 ? curwin->w_alt_fnum : Prenum,
-                            0, GETF_ALT, false);
+      buflist_getfile(Prenum == 0 ? curwin->w_alt_fnum : Prenum,
+                      0, GETF_ALT, false);
     }
     break;
 
@@ -610,7 +610,7 @@ wingotofile:
     LANGMAP_ADJUST(xchar, true);
     no_mapping--;
     allow_keys--;
-    (void)add_to_showcmd(xchar);
+    add_to_showcmd(xchar);
 
     switch (xchar) {
     case '}':
@@ -1206,7 +1206,7 @@ int win_split_ins(int size, int flags, win_T *new_wp, int dir)
     CLEAR_FIELD(wp->w_border_adj);
   }
 
-  int before;
+  bool before;
   frame_T *curfrp;
 
   // Reorganise the tree of frames to insert the new window.
@@ -1398,7 +1398,7 @@ int win_split_ins(int size, int flags, win_T *new_wp, int dir)
   }
 
   if (flags & (WSP_TOP | WSP_BOT)) {
-    (void)win_comp_pos();
+    win_comp_pos();
   }
 
   // Both windows need redrawing.  Update all status lines, in case they
@@ -1746,7 +1746,7 @@ static void win_exchange(int Prenum)
   frame_fix_width(curwin);
   frame_fix_width(wp);
 
-  (void)win_comp_pos();                 // recompute window positions
+  win_comp_pos();                 // recompute window positions
 
   if (wp->w_buffer != curbuf) {
     reset_VIsual_and_resel();
@@ -1833,7 +1833,7 @@ static void win_rotate(bool upwards, int count)
     frame_fix_width(wp2);
 
     // recompute w_winrow and w_wincol for all windows
-    (void)win_comp_pos();
+    win_comp_pos();
   }
 
   wp1->w_pos_changed = true;
@@ -1870,14 +1870,14 @@ static void win_totop(int size, int flags)
     }
   } else {
     // Remove the window and frame from the tree of frames.
-    (void)winframe_remove(curwin, &dir, NULL);
+    winframe_remove(curwin, &dir, NULL);
   }
   win_remove(curwin, NULL);
   last_status(false);       // may need to remove last status line
-  (void)win_comp_pos();     // recompute window positions
+  win_comp_pos();     // recompute window positions
 
   // Split a window on the desired side and put the window there.
-  (void)win_split_ins(size, flags, curwin, dir);
+  win_split_ins(size, flags, curwin, dir);
   if (!(flags & WSP_VERT)) {
     win_setheight(height);
     if (p_ea) {
@@ -1944,7 +1944,7 @@ void win_move_after(win_T *win1, win_T *win2)
     win_append(win2, win1);
     frame_append(win2->w_frame, win1->w_frame);
 
-    (void)win_comp_pos();  // recompute w_winrow for all windows
+    win_comp_pos();  // recompute w_winrow for all windows
     redraw_later(curwin, UPD_NOT_VALID);
   }
   win_enter(win1, false);
@@ -2023,7 +2023,7 @@ static void win_equal_rec(win_T *next_curwin, bool current, frame_T *topfr, int
   int totwincount = 0;
   int next_curwin_size = 0;
   int room = 0;
-  int has_next_curwin = 0;
+  bool has_next_curwin = false;
 
   if (topfr->fr_layout == FR_LEAF) {
     // Set the width/height of this frame.
@@ -2814,7 +2814,7 @@ int win_close(win_T *win, bool free_buf, bool force)
       // only resize that frame.  Otherwise resize all windows.
       win_equal(curwin, curwin->w_frame->fr_parent == win_frame, dir);
     } else {
-      (void)win_comp_pos();
+      win_comp_pos();
       win_fix_scroll(false);
     }
   }
@@ -3031,7 +3031,7 @@ void win_free_all(void)
     win_T *wp = lastwin;
     win_remove(lastwin, NULL);
     int dummy;
-    (void)win_free_mem(wp, &dummy, NULL);
+    win_free_mem(wp, &dummy, NULL);
     for (int i = 0; i < AUCMD_WIN_COUNT; i++) {
       if (aucmd_win[i].auc_win == wp) {
         aucmd_win[i].auc_win = NULL;
@@ -3042,7 +3042,7 @@ void win_free_all(void)
   for (int i = 0; i < AUCMD_WIN_COUNT; i++) {
     if (aucmd_win[i].auc_win != NULL) {
       int dummy;
-      (void)win_free_mem(aucmd_win[i].auc_win, &dummy, NULL);
+      win_free_mem(aucmd_win[i].auc_win, &dummy, NULL);
       aucmd_win[i].auc_win = NULL;
     }
   }
@@ -3051,7 +3051,7 @@ void win_free_all(void)
 
   while (firstwin != NULL) {
     int dummy;
-    (void)win_free_mem(firstwin, &dummy, NULL);
+    win_free_mem(firstwin, &dummy, NULL);
   }
 
   // No window should be used after this. Set curwin to NULL to crash
@@ -5221,7 +5221,7 @@ void win_new_screen_rows(void)
     frame_new_height(topframe, h, false, false);
   }
 
-  (void)win_comp_pos();  // recompute w_winrow and w_wincol
+  win_comp_pos();  // recompute w_winrow and w_wincol
   win_reconfig_floats();  // The size of floats might change
   compute_cmdrow();
   curtab->tp_ch_used = p_ch;
@@ -5245,7 +5245,7 @@ void win_new_screen_cols(void)
     frame_new_width(topframe, Columns, false, false);
   }
 
-  (void)win_comp_pos();  // recompute w_winrow and w_wincol
+  win_comp_pos();  // recompute w_winrow and w_wincol
   win_reconfig_floats();  // The size of floats might change
 }
 
@@ -5469,8 +5469,8 @@ void may_trigger_win_scrolled_resized(void)
   int cwsr = check_window_scroll_resize(&size_count,
                                         &first_scroll_win, &first_size_win,
                                         NULL, NULL);
-  int trigger_resize = do_resize && size_count > 0;
-  int trigger_scroll = do_scroll && cwsr != 0;
+  bool trigger_resize = do_resize && size_count > 0;
+  bool trigger_scroll = do_scroll && cwsr != 0;
   if (!trigger_resize && !trigger_scroll) {
     return;  // no relevant changes
   }
@@ -5480,7 +5480,7 @@ void may_trigger_win_scrolled_resized(void)
     // Create the list for v:event.windows before making the snapshot.
     // windows_list = tv_list_alloc_with_items(size_count);
     windows_list = tv_list_alloc(size_count);
-    (void)check_window_scroll_resize(NULL, NULL, NULL, windows_list, NULL);
+    check_window_scroll_resize(NULL, NULL, NULL, windows_list, NULL);
   }
 
   dict_T *scroll_dict = NULL;
@@ -5488,7 +5488,7 @@ void may_trigger_win_scrolled_resized(void)
     // Create the dict with entries for v:event before making the snapshot.
     scroll_dict = tv_dict_alloc();
     scroll_dict->dv_refcount = 1;
-    (void)check_window_scroll_resize(NULL, NULL, NULL, NULL, scroll_dict);
+    check_window_scroll_resize(NULL, NULL, NULL, NULL, scroll_dict);
   }
 
   // WinScrolled/WinResized are triggered only once, even when multiple
@@ -5572,7 +5572,7 @@ void win_size_restore(garray_T *gap)
       }
     }
     // recompute the window positions
-    (void)win_comp_pos();
+    win_comp_pos();
   }
 }
 
@@ -5865,7 +5865,7 @@ void win_setwidth_win(int width, win_T *wp)
     frame_setwidth(wp->w_frame, width + wp->w_vsep_width);
 
     // recompute the window positions
-    (void)win_comp_pos();
+    win_comp_pos();
     redraw_all_later(UPD_NOT_VALID);
   }
 }
@@ -6250,7 +6250,7 @@ void win_drag_vsep_line(win_T *dragwin, int offset)
       fr = fr->fr_next;
     }
   }
-  (void)win_comp_pos();
+  win_comp_pos();
   redraw_all_later(UPD_NOT_VALID);
 }
 
@@ -6275,7 +6275,7 @@ void set_fraction(win_T *wp)
 /// TODO(vim): Ensure this also works with wrapped lines.
 /// Requires a not fully visible cursor line to be allowed at the bottom of
 /// a window("zb"), probably only when 'smoothscroll' is also set.
-void win_fix_scroll(int resize)
+void win_fix_scroll(bool resize)
 {
   if (*p_spk == 'c') {
     return;  // 'splitkeep' is "cursor"
@@ -6446,7 +6446,7 @@ void scroll_to_fraction(win_T *wp, int prev_height)
       }
     } else if (sline > 0) {
       while (sline > 0 && lnum > 1) {
-        (void)hasFoldingWin(wp, lnum, &lnum, NULL, true, NULL);
+        hasFoldingWin(wp, lnum, &lnum, NULL, true, NULL);
         if (lnum == 1) {
           // first line in buffer is folded
           line_size = 1;
@@ -6466,7 +6466,7 @@ void scroll_to_fraction(win_T *wp, int prev_height)
       if (sline < 0) {
         // Line we want at top would go off top of screen.  Use next
         // line instead.
-        (void)hasFoldingWin(wp, lnum, NULL, &lnum, true, NULL);
+        hasFoldingWin(wp, lnum, NULL, &lnum, true, NULL);
         lnum++;
         wp->w_wrow -= line_size + sline;
       } else if (sline > 0) {
@@ -6632,7 +6632,7 @@ void command_height(void)
       }
 
       // Recompute window positions.
-      (void)win_comp_pos();
+      win_comp_pos();
 
       // clear the lines added to cmdline
       if (full_screen) {
@@ -6652,7 +6652,7 @@ void command_height(void)
 
   // Recompute window positions.
   if (frp != lastwin->w_frame) {
-    (void)win_comp_pos();
+    win_comp_pos();
   }
 }
 
@@ -6868,7 +6868,7 @@ static bool resize_frame_for_status(frame_T *fr)
   } else if (fp != fr) {
     frame_new_height(fp, fp->fr_height - 1, false, false);
     frame_fix_height(wp);
-    (void)win_comp_pos();
+    win_comp_pos();
   } else {
     win_new_height(wp, wp->w_height - 1);
   }
@@ -6890,7 +6890,7 @@ static bool resize_frame_for_winbar(frame_T *fr)
   frame_new_height(fp, fp->fr_height - 1, false, false);
   win_new_height(wp, wp->w_height + 1);
   frame_fix_height(wp);
-  (void)win_comp_pos();
+  win_comp_pos();
 
   return true;
 }
@@ -7226,7 +7226,7 @@ void restore_snapshot(int idx, int close_curwin)
       && curtab->tp_snapshot[idx]->fr_height == topframe->fr_height
       && check_snapshot_rec(curtab->tp_snapshot[idx], topframe) == OK) {
     win_T *wp = restore_snapshot_rec(curtab->tp_snapshot[idx], topframe);
-    (void)win_comp_pos();
+    win_comp_pos();
     if (wp != NULL && close_curwin) {
       win_goto(wp);
     }
diff --git a/src/nvim/winfloat.c b/src/nvim/winfloat.c
index dc29c08c14..c732ad09ed 100644
--- a/src/nvim/winfloat.c
+++ b/src/nvim/winfloat.c
@@ -57,7 +57,7 @@ win_T *win_new_float(win_T *wp, bool last, FloatConfig fconfig, Error *err)
     int dir;
     winframe_remove(wp, &dir, NULL);
     XFREE_CLEAR(wp->w_frame);
-    (void)win_comp_pos();  // recompute window positions
+    win_comp_pos();  // recompute window positions
     win_remove(wp, NULL);
     win_append(lastwin_nofloating(), wp);
   }