*: Fix linter errors

16 files changed, 148 insertions, 141 deletions

diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index eeb9f45bbc..d98df6a06e 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -1755,7 +1755,7 @@ static const char *list_arg_vars(exarg_T *eap, const char *arg, int *first)
       // get_name_len() takes care of expanding curly braces
       name_start = name = arg;
       char *tofree;
-      len = get_name_len(&arg, &tofree, TRUE, TRUE);
+      len = get_name_len(&arg, &tofree, true, true);
       if (len <= 0) {
         /* This is mainly to keep test 49 working: when expanding
          * curly braces fails overrule the exception error message. */
@@ -1775,7 +1775,7 @@ static const char *list_arg_vars(exarg_T *eap, const char *arg, int *first)
         } else {
           // handle d.key, l[idx], f(expr)
           const char *const arg_subsc = arg;
-          if (handle_subscript(&arg, &tv, TRUE, TRUE) == FAIL) {
+          if (handle_subscript(&arg, &tv, true, true) == FAIL) {
             error = true;
           } else {
             if (arg == arg_subsc && len == 2 && name[1] == ':') {
@@ -1844,15 +1844,15 @@ ex_let_one (
     ++arg;
     name = arg;
     len = get_env_len(&arg);
-    if (len == 0)
+    if (len == 0) {
       EMSG2(_(e_invarg2), name - 1);
-    else {
-      if (op != NULL && (*op == '+' || *op == '-'))
+    } else {
+      if (op != NULL && (*op == '+' || *op == '-')) {
         EMSG2(_(e_letwrong), op);
-      else if (endchars != NULL
-               && vim_strchr(endchars, *skipwhite(arg)) == NULL)
+      } else if (endchars != NULL
+                 && vim_strchr(endchars, *skipwhite(arg)) == NULL) {
         EMSG(_(e_letunexp));
-      else if (!check_secure()) {
+      } else if (!check_secure()) {
         const char_u c1 = name[len];
         name[len] = NUL;
         char_u *p = get_tv_string_chk(tv);
@@ -1904,15 +1904,16 @@ ex_let_one (
       if (s != NULL && op != NULL && *op != '=') {
         opt_type = get_option_value(arg, &numval, &stringval, opt_flags);
         if ((opt_type == 1 && *op == '.')
-            || (opt_type == 0 && *op != '.'))
+            || (opt_type == 0 && *op != '.')) {
           EMSG2(_(e_letwrong), op);
-        else {
-          if (opt_type == 1) {          /* number */
-            if (*op == '+')
+        } else {
+          if (opt_type == 1) {  // number
+            if (*op == '+') {
               n = numval + n;
-            else
+            } else {
               n = numval - n;
-          } else if (opt_type == 0 && stringval != NULL) {     /* string */
+            }
+          } else if (opt_type == 0 && stringval != NULL) {  // string
             s = concat_str(stringval, s);
             xfree(stringval);
             stringval = s;
@@ -1963,7 +1964,7 @@ ex_let_one (
   else if (eval_isnamec1(*arg) || *arg == '{') {
     lval_T lv;
 
-    char_u *const p = get_lval(arg, tv, &lv, FALSE, FALSE, 0, FNE_CHECK_START);
+    char_u *const p = get_lval(arg, tv, &lv, false, false, 0, FNE_CHECK_START);
     if (p != NULL && lv.ll_name != NULL) {
       if (endchars != NULL && vim_strchr(endchars, *skipwhite(p)) == NULL)
         EMSG(_(e_letunexp));
@@ -2075,8 +2076,9 @@ get_lval (
   *p = NUL;
   v = find_var((const char *)lp->ll_name, STRLEN(lp->ll_name), &ht,
                flags & GLV_NO_AUTOLOAD);
-  if (v == NULL && !quiet)
+  if (v == NULL && !quiet) {
     EMSG2(_(e_undefvar), lp->ll_name);
+  }
   *p = cc;
   if (v == NULL)
     return NULL;
@@ -2850,9 +2852,10 @@ void ex_call(exarg_T *eap)
       break;
     }
 
-    /* Handle a function returning a Funcref, Dictionary or List. */
-    if (handle_subscript((const char **)&arg, &rettv, !eap->skip, TRUE) == FAIL) {
-      failed = TRUE;
+    // Handle a function returning a Funcref, Dictionary or List.
+    if (handle_subscript((const char **)&arg, &rettv, !eap->skip, true)
+        == FAIL) {
+      failed = true;
       break;
     }
 
@@ -3113,18 +3116,19 @@ static int do_lock_var(lval_T *lp, char_u *name_end, int deep, int lock)
     cc = *name_end;
     *name_end = NUL;
 
-    /* Normal name or expanded name. */
-    if (check_changedtick(lp->ll_name))
+    // Normal name or expanded name.
+    if (check_changedtick(lp->ll_name)) {
       ret = FAIL;
-    else {
+    } else {
       di = find_var((const char *)lp->ll_name, STRLEN(lp->ll_name), NULL, true);
-      if (di == NULL)
+      if (di == NULL) {
         ret = FAIL;
-      else {
-        if (lock)
+      } else {
+        if (lock) {
           di->di_flags |= DI_FLAGS_LOCK;
-        else
+        } else {
           di->di_flags &= ~DI_FLAGS_LOCK;
+        }
         item_lock(&di->di_tv, deep, lock);
       }
     }
@@ -4727,7 +4731,7 @@ static int get_option_tv(const char **const arg, typval_T *const rettv,
 
   c = *option_end;
   *option_end = NUL;
-  opt_type = get_option_value((char_u *)*arg, &numval,
+  opt_type = get_option_value((char_u *)(*arg), &numval,
                               rettv == NULL ? NULL : &stringval, opt_flags);
 
   if (opt_type == -3) {                 /* invalid name */
@@ -7011,7 +7015,7 @@ static char_u *deref_func_name(const char *name, int *lenp,
     *partialp = NULL;
   }
 
-  dictitem_T *const v = find_var(name, (size_t)*lenp, NULL, no_autoload);
+  dictitem_T *const v = find_var(name, (size_t)(*lenp), NULL, no_autoload);
   if (v != NULL && v->di_tv.v_type == VAR_FUNC) {
     if (v->di_tv.vval.v_string == NULL) {  // just in case
       *lenp = 0;
@@ -7250,9 +7254,7 @@ call_func(
     error = ERROR_UNKNOWN;
 
     if (!builtin_function((const char *)rfname, -1)) {
-      /*
-       * User defined function.
-       */
+      // User defined function.
       fp = find_func(rfname);
 
       /* Trigger FuncUndefined event, may load the function. */
@@ -7265,7 +7267,7 @@ call_func(
       // Try loading a package.
       if (fp == NULL && script_autoload((const char *)rfname, STRLEN(rfname),
                                         true) && !aborting()) {
-        /* loaded a package, search for the function again */
+        // Loaded a package, search for the function again.
         fp = find_func(rfname);
       }
 
@@ -8965,7 +8967,7 @@ static void f_exists(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     // get_name_len() takes care of expanding curly braces
     const char *name = p;
     char *tofree;
-    len = get_name_len((const char **)&p, &tofree, TRUE, FALSE);
+    len = get_name_len((const char **)&p, &tofree, true, false);
     if (len > 0) {
       if (tofree != NULL) {
         name = tofree;
@@ -11837,7 +11839,7 @@ static void get_user_input(typval_T *argvars, typval_T *rettv, int inputdialog)
       msg_start();
       msg_clr_eos();
       msg_puts_attr((const char *)prompt, echo_attr);
-      msg_didout = FALSE;
+      msg_didout = false;
       msg_starthere();
       *p = c;
     }
@@ -12899,9 +12901,9 @@ static void get_maparg(typval_T *argvars, typval_T *rettv, int exact)
     rettv_dict_alloc(rettv);
     if (rhs != NULL) {
       // Return a dictionary.
-      char_u      *lhs = str2special_save(mp->m_keys, TRUE);
+      char_u *lhs = str2special_save(mp->m_keys, true);
       char *const mapmode = map_mode_to_chars(mp->m_mode);
-      dict_T      *dict = rettv->vval.v_dict;
+      dict_T *dict = rettv->vval.v_dict;
 
       dict_add_nr_str(dict, "lhs",     0L, lhs);
       dict_add_nr_str(dict, "rhs",     0L, mp->m_orig_str);
@@ -16841,7 +16843,7 @@ static void f_synIDattr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
       p = highlight_has_attr(id, HL_ITALIC, modec);
     break;
 
-  case 'n':                                             /* name */
+  case 'n':                                             // name
     p = (char_u *)get_highlight_name(NULL, id - 1);
     break;
 
@@ -18423,7 +18425,7 @@ static int get_name_len(const char **const arg,
 
   if ((*arg)[0] == (char)K_SPECIAL && (*arg)[1] == (char)KS_EXTRA
       && (*arg)[2] == (char)KE_SNR) {
-    /* hard coded <SNR>, already translated */
+    // Hard coded <SNR>, already translated.
     *arg += 3;
     return get_id_len(arg) + 3;
   }
@@ -18436,7 +18438,7 @@ static int get_name_len(const char **const arg,
   /*
    * Find the end of the name; check for {} construction.
    */
-  const char *p = (const char *)find_name_end((char_u *)*arg,
+  const char *p = (const char *)find_name_end((char_u *)(*arg),
                                               &expr_start,
                                               &expr_end,
                                               len > 0 ? 0 : FNE_CHECK_START);
@@ -18451,7 +18453,7 @@ static int get_name_len(const char **const arg,
      * Include any <SID> etc in the expanded string:
      * Thus the -len here.
      */
-    char_u *temp_string = make_expanded_name((char_u *)*arg - len, expr_start,
+    char_u *temp_string = make_expanded_name((char_u *)(*arg) - len, expr_start,
                                              expr_end, (char_u *)p);
     if (temp_string == NULL) {
       return -1;
@@ -18919,8 +18921,8 @@ static int get_var_tv(
  * Also handle function call with Funcref variable: func(expr)
  * Can all be combined: dict.func(expr)[idx]['func'](expr)
  */
-static int 
-handle_subscript (
+static int
+handle_subscript(
     const char **const arg,
     typval_T *rettv,
     int evaluate,                   /* do more than finding the end */
@@ -19786,7 +19788,7 @@ char_u *get_var_value(const char *const name)
 {
   dictitem_T  *v;
 
-  v = find_var(name, strlen(name), NULL, FALSE);
+  v = find_var(name, strlen(name), NULL, false);
   if (v == NULL) {
     return NULL;
   }
@@ -20341,7 +20343,7 @@ void ex_echo(exarg_T *eap)
         if (!aborting()) {
           EMSG2(_(e_invexpr2), p);
         }
-        need_clr_eos = FALSE;
+        need_clr_eos = false;
         break;
       }
       need_clr_eos = false;
@@ -20372,15 +20374,16 @@ void ex_echo(exarg_T *eap)
               msg_clr_eos();
               needclr = false;
             }
-            msg_putchar_attr((uint8_t)*p, echo_attr);
+            msg_putchar_attr((uint8_t)(*p), echo_attr);
           } else {
             if (has_mbyte) {
               int i = (*mb_ptr2len)((const char_u *)p);
 
               (void)msg_outtrans_len_attr((char_u *)p, i, echo_attr);
               p += i - 1;
-            } else
+            } else {
               (void)msg_outtrans_len_attr((char_u *)p, 1, echo_attr);
+            }
           }
         }
       }
@@ -20961,7 +20964,7 @@ void ex_function(exarg_T *eap)
    * If there are no errors, add the function
    */
   if (fudi.fd_dict == NULL) {
-    v = find_var((const char *)name, STRLEN(name), &ht, FALSE);
+    v = find_var((const char *)name, STRLEN(name), &ht, false);
     if (v != NULL && v->di_tv.v_type == VAR_FUNC) {
       emsg_funcname(N_("E707: Function name conflicts with variable: %s"),
           name);
@@ -21205,7 +21208,7 @@ trans_function_name (
     }
   } else {
     len = (int)(end - *pp);
-    name = deref_func_name((const char *)*pp, &len, partial,
+    name = deref_func_name((const char *)(*pp), &len, partial,
                            flags & TFN_NO_AUTOLOAD);
     if (name == *pp) {
       name = NULL;
@@ -21252,7 +21255,7 @@ trans_function_name (
   else if (lead > 0) {
     lead = 3;
     if ((lv.ll_exp_name != NULL && eval_fname_sid((const char *)lv.ll_exp_name))
-        || eval_fname_sid((const char *)*pp)) {
+        || eval_fname_sid((const char *)(*pp))) {
       // It's "s:" or "<SID>".
       if (current_SID <= 0) {
         EMSG(_(e_usingsid));
@@ -21346,7 +21349,7 @@ static void list_func_head(ufunc_T *fp, int indent)
   }
   msg_putchar('(');
   int j;
-  for (j = 0; j < fp->uf_args.ga_len; ++j) {
+  for (j = 0; j < fp->uf_args.ga_len; j++) {
     if (j) {
       msg_puts(", ");
     }
@@ -22059,7 +22062,7 @@ call_user_func (
       smsg(_("calling %s"), sourcing_name);
       if (p_verbose >= 14) {
         msg_puts("(");
-        for (int i = 0; i < argcount; ++i) {
+        for (int i = 0; i < argcount; i++) {
           if (i > 0) {
             msg_puts(", ");
           }
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index d1c063ecce..091eeaac60 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -583,8 +583,7 @@ int do_cmdline(char_u *cmdline, LineGetter fgetline,
       ++no_wait_return;
       verbose_enter_scroll();
 
-      smsg(_("line %" PRId64 ": %s"),
-          (int64_t)sourcing_lnum, cmdline_copy);
+      smsg(_("line %" PRIdLINENR ": %s"), sourcing_lnum, cmdline_copy);
       if (msg_silent == 0) {
         msg_puts("\n");  // don't overwrite this either
       }
@@ -1816,9 +1815,9 @@ static char_u * do_one_cmd(char_u **cmdlinep,
           errormsg = (char_u *)_("E493: Backwards range given");
           goto doend;
         }
-        if (ask_yesno((char_u *)
-                _("Backwards range given, OK to swap"), FALSE) != 'y')
+        if (ask_yesno(_("Backwards range given, OK to swap"), false) != 'y') {
           goto doend;
+        }
       }
       lnum = ea.line1;
       ea.line1 = ea.line2;
@@ -2586,13 +2585,11 @@ int modifier_len(char_u *cmd)
 int cmd_exists(const char *const name)
 {
   exarg_T ea;
-  int full = FALSE;
-  int i;
-  int j;
   char_u      *p;
 
-  /* Check command modifiers. */
-  for (i = 0; i < (int)ARRAY_SIZE(cmdmods); i++) {
+  // Check command modifiers.
+  for (int i = 0; i < (int)ARRAY_SIZE(cmdmods); i++) {
+    int j;
     for (j = 0; name[j] != NUL; j++) {
       if (name[j] != (char)cmdmods[i].name[j]) {
         break;
@@ -2607,6 +2604,7 @@ int cmd_exists(const char *const name)
    * For ":2match" and ":3match" we need to skip the number. */
   ea.cmd = (char_u *)((*name == '2' || *name == '3') ? name + 1 : name);
   ea.cmdidx = (cmdidx_T)0;
+  int full = false;
   p = find_command(&ea, &full);
   if (p == NULL)
     return 3;
@@ -8250,9 +8248,9 @@ eval_vars (
   char_u      *resultbuf = NULL;
   size_t resultlen;
   buf_T       *buf;
-  int valid = VALID_HEAD + VALID_PATH;              /* assume valid result */
-  int skip_mod = FALSE;
-  char_u strbuf[30];
+  int valid = VALID_HEAD | VALID_PATH;  // Assume valid result.
+  int skip_mod = false;
+  char strbuf[30];
 
   *errormsg = NULL;
   if (escaped != NULL)
@@ -8384,8 +8382,8 @@ eval_vars (
             "E496: no autocommand buffer number to substitute for \"<abuf>\"");
         return NULL;
       }
-      sprintf((char *)strbuf, "%d", autocmd_bufnr);
-      result = strbuf;
+      snprintf(strbuf, sizeof(strbuf), "%d", autocmd_bufnr);
+      result = (char_u *)strbuf;
       break;
 
     case SPEC_AMATCH:           /* match name for autocommand */
@@ -8410,8 +8408,8 @@ eval_vars (
         *errormsg = (char_u *)_("E842: no line number to use for \"<slnum>\"");
         return NULL;
       }
-      sprintf((char *)strbuf, "%" PRId64, (int64_t)sourcing_lnum);
-      result = strbuf;
+      snprintf(strbuf, sizeof(strbuf), "%" PRIdLINENR, sourcing_lnum);
+      result = (char_u *)strbuf;
       break;
     default:
       // should not happen
diff --git a/src/nvim/ex_eval.c b/src/nvim/ex_eval.c
index ab8118e491..4bb6f97035 100644
--- a/src/nvim/ex_eval.c
+++ b/src/nvim/ex_eval.c
@@ -542,7 +542,7 @@ static void discard_exception(except_T *excp, int was_finished)
     } else {
       verbose_leave();
     }
-    STRNCPY(IObuff, saved_IObuff, IOSIZE);
+    xstrlcpy((char *)IObuff, (const char *)saved_IObuff, IOSIZE);
     xfree(saved_IObuff);
   }
   if (excp->type != ET_INTERRUPT)
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 9eea721463..d99c8d02f7 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -3903,36 +3903,35 @@ ExpandFromContext (
       ExpandFunc func;
       int ic;
       int escaped;
-    } tab[] =
-    {
-      {EXPAND_COMMANDS, get_command_name, FALSE, TRUE},
-      {EXPAND_BEHAVE, get_behave_arg, TRUE, TRUE},
-      {EXPAND_HISTORY, get_history_arg, TRUE, TRUE},
-      {EXPAND_USER_COMMANDS, get_user_commands, FALSE, TRUE},
-      {EXPAND_USER_ADDR_TYPE, get_user_cmd_addr_type, FALSE, TRUE},
-      {EXPAND_USER_CMD_FLAGS, get_user_cmd_flags, FALSE, TRUE},
-      {EXPAND_USER_NARGS, get_user_cmd_nargs, FALSE, TRUE},
-      {EXPAND_USER_COMPLETE, get_user_cmd_complete, FALSE, TRUE},
-      {EXPAND_USER_VARS, get_user_var_name, FALSE, TRUE},
-      {EXPAND_FUNCTIONS, get_function_name, FALSE, TRUE},
-      {EXPAND_USER_FUNC, get_user_func_name, FALSE, TRUE},
-      {EXPAND_EXPRESSION, get_expr_name, FALSE, TRUE},
-      {EXPAND_MENUS, get_menu_name, FALSE, TRUE},
-      {EXPAND_MENUNAMES, get_menu_names, FALSE, TRUE},
-      {EXPAND_SYNTAX, get_syntax_name, TRUE, TRUE},
-      {EXPAND_SYNTIME, get_syntime_arg, TRUE, TRUE},
-      {EXPAND_HIGHLIGHT, (ExpandFunc)get_highlight_name, TRUE, TRUE},
-      {EXPAND_EVENTS, get_event_name, TRUE, TRUE},
-      {EXPAND_AUGROUP, get_augroup_name, TRUE, TRUE},
-      {EXPAND_CSCOPE, get_cscope_name, TRUE, TRUE},
-      {EXPAND_SIGN, get_sign_name, TRUE, TRUE},
-      {EXPAND_PROFILE, get_profile_name, TRUE, TRUE},
+    } tab[] = {
+      { EXPAND_COMMANDS, get_command_name, false, true },
+      { EXPAND_BEHAVE, get_behave_arg, true, true },
+      { EXPAND_HISTORY, get_history_arg, true, true },
+      { EXPAND_USER_COMMANDS, get_user_commands, false, true },
+      { EXPAND_USER_ADDR_TYPE, get_user_cmd_addr_type, false, true },
+      { EXPAND_USER_CMD_FLAGS, get_user_cmd_flags, false, true },
+      { EXPAND_USER_NARGS, get_user_cmd_nargs, false, true },
+      { EXPAND_USER_COMPLETE, get_user_cmd_complete, false, true },
+      { EXPAND_USER_VARS, get_user_var_name, false, true },
+      { EXPAND_FUNCTIONS, get_function_name, false, true },
+      { EXPAND_USER_FUNC, get_user_func_name, false, true },
+      { EXPAND_EXPRESSION, get_expr_name, false, true },
+      { EXPAND_MENUS, get_menu_name, false, true },
+      { EXPAND_MENUNAMES, get_menu_names, false, true },
+      { EXPAND_SYNTAX, get_syntax_name, true, true },
+      { EXPAND_SYNTIME, get_syntime_arg, true, true },
+      { EXPAND_HIGHLIGHT, (ExpandFunc)get_highlight_name, true, true },
+      { EXPAND_EVENTS, get_event_name, true, true },
+      { EXPAND_AUGROUP, get_augroup_name, true, true },
+      { EXPAND_CSCOPE, get_cscope_name, true, true },
+      { EXPAND_SIGN, get_sign_name, true, true },
+      { EXPAND_PROFILE, get_profile_name, true, true },
 #ifdef HAVE_WORKING_LIBINTL
-      {EXPAND_LANGUAGE, get_lang_arg, TRUE, FALSE},
-      {EXPAND_LOCALES, get_locales, TRUE, FALSE},
+      { EXPAND_LANGUAGE, get_lang_arg, true, false },
+      { EXPAND_LOCALES, get_locales, true, false },
 #endif
-      {EXPAND_ENV_VARS, get_env_name, TRUE, TRUE},
-      {EXPAND_USER, get_users, TRUE, FALSE},
+      { EXPAND_ENV_VARS, get_env_name, true, true },
+      { EXPAND_USER, get_users, true, false },
     };
     int i;
 
diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index efb16e880e..4ea5121a91 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -3895,15 +3895,15 @@ static int check_mtime(buf_T *buf, FileInfo *file_info)
   if (buf->b_mtime_read != 0
       && time_differs(file_info->stat.st_mtim.tv_sec,
                       buf->b_mtime_read)) {
-    msg_scroll = TRUE;              /* don't overwrite messages here */
-    msg_silent = 0;                 /* must give this prompt */
+    msg_scroll = true;  // Don't overwrite messages here.
+    msg_silent = 0;     // Must give this prompt.
     // Don't use emsg() here, don't want to flush the buffers.
     msg_attr(_("WARNING: The file has been changed since reading it!!!"),
-        hl_attr(HLF_E));
-    if (ask_yesno((char_u *)_("Do you really want to write to it"),
-            TRUE) == 'n')
+             hl_attr(HLF_E));
+    if (ask_yesno(_("Do you really want to write to it"), true) == 'n') {
       return FAIL;
-    msg_scroll = FALSE;             /* always overwrite the file message now */
+    }
+    msg_scroll = false;  // Always overwrite the file message now.
   }
   return OK;
 }
@@ -5384,10 +5384,8 @@ char_u *vim_tempname(void)
 
 static AutoPatCmd *active_apc_list = NULL; /* stack of active autocommands */
 
-/*
- * augroups stores a list of autocmd group names.
- */
-static garray_T augroups = {0, 0, sizeof(char_u *), 10, NULL};
+/// List of autocmd group names
+static garray_T augroups = { 0, 0, sizeof(char_u *), 10, NULL };
 #define AUGROUP_NAME(i) (((char **)augroups.ga_data)[i])
 
 /*
@@ -5592,8 +5590,9 @@ static int au_new_group(char_u *name)
     }
 
     AUGROUP_NAME(i) = xstrdup((char *)name);
-    if (i == augroups.ga_len)
-      ++augroups.ga_len;
+    if (i == augroups.ga_len) {
+      augroups.ga_len++;
+    }
   }
 
   return i;
diff --git a/src/nvim/getchar.c b/src/nvim/getchar.c
index ae890d46bc..0717978ead 100644
--- a/src/nvim/getchar.c
+++ b/src/nvim/getchar.c
@@ -3227,7 +3227,7 @@ showmap (
   while (++len <= 3)
     msg_putchar(' ');
 
-  /* Display the LHS.  Get length of what we write. */
+  // Display the LHS.  Get length of what we write.
   len = (size_t)msg_outtrans_special(mp->m_keys, true);
   do {
     msg_putchar(' ');                   /* padd with blanks */
@@ -3252,8 +3252,8 @@ showmap (
   if (*mp->m_str == NUL) {
     msg_puts_attr("<Nop>", hl_attr(HLF_8));
   } else {
-    /* Remove escaping of CSI, because "m_str" is in a format to be used
-     * as typeahead. */
+    // Remove escaping of CSI, because "m_str" is in a format to be used
+    // as typeahead.
     char_u *s = vim_strsave(mp->m_str);
     vim_unescape_csi(s);
     msg_outtrans_special(s, FALSE);
diff --git a/src/nvim/menu.c b/src/nvim/menu.c
index cbaddb00d0..529978e3f0 100644
--- a/src/nvim/menu.c
+++ b/src/nvim/menu.c
@@ -758,7 +758,7 @@ static void show_menus_recursive(vimmenu_T *menu, int modes, int depth)
         if (*menu->strings[bit] == NUL) {
           msg_puts_attr("<Nop>", hl_attr(HLF_8));
         } else {
-          msg_outtrans_special(menu->strings[bit], FALSE);
+          msg_outtrans_special(menu->strings[bit], false);
         }
       }
   } else {
diff --git a/src/nvim/message.c b/src/nvim/message.c
index 4cc1350938..299cec5d40 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -1177,13 +1177,14 @@ int msg_outtrans_len_attr(char_u *msgstr, int len, int attr)
    * Normal characters are printed several at a time.
    */
   while (--len >= 0) {
-    if (enc_utf8)
-      /* Don't include composing chars after the end. */
+    if (enc_utf8) {
+      // Don't include composing chars after the end.
       mb_l = utfc_ptr2len_len((char_u *)str, len + 1);
-    else if (has_mbyte)
+    } else if (has_mbyte) {
       mb_l = (*mb_ptr2len)((char_u *)str);
-    else
+    } else {
       mb_l = 1;
+    }
     if (has_mbyte && mb_l > 1) {
       c = (*mb_ptr2char)((char_u *)str);
       if (vim_isprintc(c)) {
@@ -1680,9 +1681,10 @@ static void msg_puts_display(const char_u *str, int maxlen, int attr,
         } else {
           msg_screen_putchar(*s++, attr);
         }
-        did_last_char = TRUE;
-      } else
-        did_last_char = FALSE;
+        did_last_char = true;
+      } else {
+        did_last_char = false;
+      }
 
       if (p_more) {
         // Store text for scrolling back.
@@ -1784,7 +1786,7 @@ static void msg_puts_display(const char_u *str, int maxlen, int attr,
     ++s;
   }
 
-  /* output any postponed text */
+  // Output any postponed text.
   if (t_col > 0) {
     t_puts(&t_col, t_s, s, attr);
   }
@@ -1968,8 +1970,8 @@ static msgchunk_T *disp_sb_line(int row, msgchunk_T *smp)
  */
 static void t_puts(int *t_col, const char_u *t_s, const char_u *s, int attr)
 {
-  /* output postponed text */
-  msg_didout = TRUE;            /* remember that line is not empty */
+  // Output postponed text.
+  msg_didout = true;  // Remember that line is not empty.
   screen_puts_len((char_u *)t_s, (int)(s - t_s), msg_row, msg_col, attr);
   msg_col += *t_col;
   *t_col = 0;
diff --git a/src/nvim/misc1.c b/src/nvim/misc1.c
index f528c9e15a..db34159f24 100644
--- a/src/nvim/misc1.c
+++ b/src/nvim/misc1.c
@@ -2223,7 +2223,7 @@ change_warning (
  *
  * return the 'y' or 'n'
  */
-int ask_yesno(char_u *str, int direct)
+int ask_yesno(const char *str, bool direct)
 {
   int r = ' ';
   int save_State = State;
diff --git a/src/nvim/option.c b/src/nvim/option.c
index b1cbe3fb59..e697ab3f51 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -2570,10 +2570,10 @@ did_set_string_option (
       init_highlight(FALSE, FALSE);
 
       if (dark != (*p_bg == 'd') && get_var_value("g:colors_name") != NULL) {
-        /* The color scheme must have set 'background' back to another
-         * value, that's not what we want here.  Disable the color
-         * scheme and set the colors again. */
-        do_unlet((char_u *)"g:colors_name", TRUE);
+        // The color scheme must have set 'background' back to another
+        // value, that's not what we want here.  Disable the color
+        // scheme and set the colors again.
+        do_unlet((char_u *)"g:colors_name", true);
         free_string_option(p_bg);
         p_bg = vim_strsave((char_u *)(dark ? "dark" : "light"));
         check_string_option(&p_bg);
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index 3b86662f05..0da98713df 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -2078,7 +2078,7 @@ void qf_list(exarg_T *eap)
       msg_puts_attr((const char *)IObuff, hl_attr(HLF_N));
       if (qfp->qf_pattern != NULL) {
         qf_fmt_text(qfp->qf_pattern, IObuff, IOSIZE);
-        STRNCAT(IObuff, ":", IOSIZE);
+        xstrlcat((char *)IObuff, ":", IOSIZE);
         msg_puts((const char *)IObuff);
       }
       msg_puts(" ");
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index de16572dc2..6df443754b 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -6725,7 +6725,7 @@ int showmode(void)
             msg_puts_attr((const char *)edit_submode, attr);
           }
           if (edit_submode_extra != NULL) {
-            MSG_PUTS_ATTR(" ", attr);              /* add a space in between */
+            MSG_PUTS_ATTR(" ", attr);  // Add a space in between.
             if ((int)edit_submode_highl < (int)HLF_COUNT) {
               sub_attr = hl_attr(edit_submode_highl);
             } else {
diff --git a/src/nvim/spell.c b/src/nvim/spell.c
index 16370ffdc3..dea09cd633 100644
--- a/src/nvim/spell.c
+++ b/src/nvim/spell.c
@@ -13006,7 +13006,7 @@ void ex_spellinfo(exarg_T *eap)
   }
 
   msg_start();
-  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len && !got_int; ++lpi) {
+  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len && !got_int; lpi++) {
     langp_T *const lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
     msg_puts("file: ");
     msg_puts((const char *)lp->lp_slang->sl_fname);
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index f13f7a702e..0a27d9dd92 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -3649,7 +3649,9 @@ static void syn_list_cluster(int id)
   }
 }
 
-static void put_id_list(const char *name, short *list, int attr)
+static void put_id_list(const char *name,
+                        short *list,  // NOLINT(runtime/int)
+                        int attr)
 {
   short               *p;
 
@@ -5519,19 +5521,21 @@ void ex_ownsyntax(exarg_T *eap)
     clear_string_option(&curwin->w_s->b_syn_isk);
   }
 
-  /* save value of b:current_syntax */
+  // Save value of b:current_syntax.
   old_value = get_var_value("b:current_syntax");
-  if (old_value != NULL)
+  if (old_value != NULL) {
     old_value = vim_strsave(old_value);
+  }
 
   /* Apply the "syntax" autocommand event, this finds and loads the syntax
    * file. */
   apply_autocmds(EVENT_SYNTAX, eap->arg, curbuf->b_fname, TRUE, curbuf);
 
-  /* move value of b:current_syntax to w:current_syntax */
+  // Move value of b:current_syntax to w:current_syntax.
   new_value = get_var_value("b:current_syntax");
-  if (new_value != NULL)
+  if (new_value != NULL) {
     set_internal_string_var((char_u *)"w:current_syntax", new_value);
+  }
 
   /* restore value of b:current_syntax */
   if (old_value == NULL)
@@ -7534,11 +7538,11 @@ static void highlight_list_two(int cnt, int attr)
 const char *get_highlight_name(expand_T *const xp, const int idx)
   FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  // TODO: 'xp' is unused
+  // TODO(justinmk): 'xp' is unused
   if (idx == highlight_ga.ga_len && include_none != 0) {
     return "none";
   } else if (idx == highlight_ga.ga_len + include_none
-      && include_default != 0) {
+             && include_default != 0) {
     return "default";
   } else if (idx == highlight_ga.ga_len + include_none + include_default
              && include_link != 0) {
diff --git a/src/nvim/tag.c b/src/nvim/tag.c
index 404b58a7eb..e723ea20c9 100644
--- a/src/nvim/tag.c
+++ b/src/nvim/tag.c
@@ -541,9 +541,10 @@ do_tag (
           vim_snprintf((char *)IObuff + 1, IOSIZE - 1, "%2d %s ", i + 1,
                        mt_names[matches[i][0] & MT_MASK]);
           msg_puts((const char *)IObuff);
-          if (tagp.tagkind != NULL)
+          if (tagp.tagkind != NULL) {
             msg_outtrans_len(tagp.tagkind,
-                (int)(tagp.tagkind_end - tagp.tagkind));
+                             (int)(tagp.tagkind_end - tagp.tagkind));
+          }
           msg_advance(13);
           msg_outtrans_len_attr(tagp.tagname,
               (int)(tagp.tagname_end - tagp.tagname),
@@ -864,8 +865,9 @@ do_tag (
             msg(IObuff);
           }
           msg_scroll = true;  // Don't overwrite this message.
-        } else
+        } else {
           give_warning(IObuff, ic);
+        }
         if (ic && !msg_scrolled && msg_silent == 0) {
           ui_flush();
           os_delay(1000L, true);
diff --git a/src/nvim/undo.c b/src/nvim/undo.c
index 8470a8303e..8cedfcb905 100644
--- a/src/nvim/undo.c
+++ b/src/nvim/undo.c
@@ -2514,7 +2514,7 @@ void ex_undolist(exarg_T *eap)
     msg_start();
     msg_puts_attr(_("number changes  when               saved"),
                   hl_attr(HLF_T));
-    for (int i = 0; i < ga.ga_len && !got_int; ++i) {
+    for (int i = 0; i < ga.ga_len && !got_int; i++) {
       msg_putchar('\n');
       if (got_int) {
         break;