Merge pull request #16014 from dundargoc/refactor/reduce-char-casts

refactor: reduce number of unique char casts

26 files changed, 107 insertions, 116 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index e58a59e872..44552bcb26 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -712,7 +712,7 @@ Object nvim_call_dict_function(Object dict, String fn, Array args, Error *err)
     }
     fn = (String) {
       .data = (char *)di->di_tv.vval.v_string,
-      .size = strlen((char *)di->di_tv.vval.v_string),
+      .size = STRLEN(di->di_tv.vval.v_string),
     };
   }
 
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 2617859381..37cc854959 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -3235,7 +3235,7 @@ void maketitle(void)
         int use_sandbox = false;
         int save_called_emsg = called_emsg;
 
-        use_sandbox = was_set_insecurely(curwin, (char_u *)"titlestring", 0);
+        use_sandbox = was_set_insecurely(curwin, "titlestring", 0);
         called_emsg = false;
         build_stl_str_hl(curwin, (char_u *)buf, sizeof(buf),
                          p_titlestring, use_sandbox,
@@ -3353,7 +3353,7 @@ void maketitle(void)
         int use_sandbox = false;
         int save_called_emsg = called_emsg;
 
-        use_sandbox = was_set_insecurely(curwin, (char_u *)"iconstring", 0);
+        use_sandbox = was_set_insecurely(curwin, "iconstring", 0);
         called_emsg = false;
         build_stl_str_hl(curwin, icon_str, sizeof(buf),
                          p_iconstring, use_sandbox,
diff --git a/src/nvim/digraph.c b/src/nvim/digraph.c
index b0fc4ee463..0fa6ebcd94 100644
--- a/src/nvim/digraph.c
+++ b/src/nvim/digraph.c
@@ -1843,12 +1843,12 @@ char_u *keymap_init(void)
     vim_snprintf(buf, buflen, "keymap/%s_%s.vim",
                  curbuf->b_p_keymap, p_enc);
 
-    if (source_runtime((char_u *)buf, 0) == FAIL) {
+    if (source_runtime(buf, 0) == FAIL) {
       // try finding "keymap/'keymap'.vim" in 'runtimepath'
       vim_snprintf(buf, buflen, "keymap/%s.vim",
                    curbuf->b_p_keymap);
 
-      if (source_runtime((char_u *)buf, 0) == FAIL) {
+      if (source_runtime(buf, 0) == FAIL) {
         xfree(buf);
         return (char_u *)N_("E544: Keymap file not found");
       }
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index ac659fbda4..b19ea36bd5 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -1191,7 +1191,7 @@ int eval_foldexpr(char_u *arg, int *cp)
 {
   typval_T tv;
   varnumber_T retval;
-  int use_sandbox = was_set_insecurely(curwin, (char_u *)"foldexpr", OPT_LOCAL);
+  int use_sandbox = was_set_insecurely(curwin, "foldexpr", OPT_LOCAL);
 
   ++emsg_off;
   if (use_sandbox) {
@@ -10224,7 +10224,7 @@ bool script_autoload(const char *const name, const size_t name_len, const bool r
     }
 
     // Try loading the package from $VIMRUNTIME/autoload/<name>.vim
-    if (source_runtime((char_u *)scriptname, 0) == OK) {
+    if (source_runtime(scriptname, 0) == OK) {
       ret = true;
     }
   }
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 17cf141b54..da129c1170 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -4362,7 +4362,7 @@ static void f_globpath(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     globpath((char_u *)tv_get_string(&argvars[0]), (char_u *)file, &ga, flags);
 
     if (rettv->v_type == VAR_STRING) {
-      rettv->vval.v_string = ga_concat_strings_sep(&ga, "\n");
+      rettv->vval.v_string = (char_u *)ga_concat_strings_sep(&ga, "\n");
     } else {
       tv_list_alloc_ret(rettv, ga.ga_len);
       for (int i = 0; i < ga.ga_len; i++) {
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index d247118589..5d43a14168 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -1439,11 +1439,11 @@ static void do_filter(linenr_T line1, linenr_T line2, exarg_T *eap, char_u *cmd,
 
     if (linecount > p_report) {
       if (do_in) {
-        vim_snprintf((char *)msg_buf, sizeof(msg_buf),
+        vim_snprintf(msg_buf, sizeof(msg_buf),
                      _("%" PRId64 " lines filtered"), (int64_t)linecount);
-        if (msg(msg_buf) && !msg_scroll) {
+        if (msg((char_u *)msg_buf) && !msg_scroll) {
           // save message to display it after redraw
-          set_keep_msg(msg_buf, 0);
+          set_keep_msg((char_u *)msg_buf, 0);
         }
       } else {
         msgmore((long)linecount);
@@ -4451,24 +4451,24 @@ bool do_sub_msg(bool count_only)
       *msg_buf = NUL;
     }
     if (sub_nsubs == 1) {
-      vim_snprintf_add((char *)msg_buf, sizeof(msg_buf),
+      vim_snprintf_add(msg_buf, sizeof(msg_buf),
                        "%s", count_only ? _("1 match") : _("1 substitution"));
     } else {
-      vim_snprintf_add((char *)msg_buf, sizeof(msg_buf),
+      vim_snprintf_add(msg_buf, sizeof(msg_buf),
                        count_only ? _("%" PRId64 " matches")
                                   : _("%" PRId64 " substitutions"),
                        (int64_t)sub_nsubs);
     }
     if (sub_nlines == 1) {
-      vim_snprintf_add((char *)msg_buf, sizeof(msg_buf),
+      vim_snprintf_add(msg_buf, sizeof(msg_buf),
                        "%s", _(" on 1 line"));
     } else {
-      vim_snprintf_add((char *)msg_buf, sizeof(msg_buf),
+      vim_snprintf_add(msg_buf, sizeof(msg_buf),
                        _(" on %" PRId64 " lines"), (int64_t)sub_nlines);
     }
-    if (msg(msg_buf)) {
+    if (msg((char_u *)msg_buf)) {
       // save message to display it after redraw
-      set_keep_msg(msg_buf, 0);
+      set_keep_msg((char_u *)msg_buf, 0);
     }
     return true;
   }
@@ -5800,8 +5800,7 @@ void ex_helptags(exarg_T *eap)
   }
 
   if (STRCMP(eap->arg, "ALL") == 0) {
-    do_in_path(p_rtp, (char_u *)"doc", DIP_ALL + DIP_DIR,
-               helptags_cb, &add_help_tags);
+    do_in_path(p_rtp, "doc", DIP_ALL + DIP_DIR, helptags_cb, &add_help_tags);
   } else {
     ExpandInit(&xpc);
     xpc.xp_context = EXPAND_DIRECTORIES;
diff --git a/src/nvim/ex_cmds2.c b/src/nvim/ex_cmds2.c
index c3cde2f15a..40a2960a85 100644
--- a/src/nvim/ex_cmds2.c
+++ b/src/nvim/ex_cmds2.c
@@ -1640,10 +1640,10 @@ void ex_compiler(exarg_T *eap)
     do_unlet(S_LEN("b:current_compiler"), true);
 
     snprintf((char *)buf, bufsize, "compiler/%s.vim", eap->arg);
-    if (source_runtime(buf, DIP_ALL) == FAIL) {
+    if (source_runtime((char *)buf, DIP_ALL) == FAIL) {
       // Try lua compiler
       snprintf((char *)buf, bufsize, "compiler/%s.lua", eap->arg);
-      if (source_runtime(buf, DIP_ALL) == FAIL) {
+      if (source_runtime((char *)buf, DIP_ALL) == FAIL) {
         EMSG2(_("E666: compiler not supported: %s"), eap->arg);
       }
     }
@@ -1823,7 +1823,7 @@ static void cmd_source(char_u *fname, exarg_T *eap)
                || eap->cstack->cs_idx >= 0);
 
     // ":source" read ex commands
-  } else if (do_source(fname, false, DOSO_NONE) == FAIL) {
+  } else if (do_source((char *)fname, false, DOSO_NONE) == FAIL) {
     EMSG2(_(e_notopen), fname);
   }
 }
@@ -2027,7 +2027,7 @@ int do_source_str(const char *cmd, const char *traceback_name)
 /// @param is_vimrc     DOSO_ value
 ///
 /// @return FAIL if file could not be opened, OK otherwise
-int do_source(char_u *fname, int check_other, int is_vimrc)
+int do_source(char *fname, int check_other, int is_vimrc)
 {
   struct source_cookie cookie;
   char_u *save_sourcing_name;
@@ -2043,7 +2043,7 @@ int do_source(char_u *fname, int check_other, int is_vimrc)
   proftime_T wait_start;
   bool trigger_source_post = false;
 
-  p = expand_env_save(fname);
+  p = expand_env_save((char_u *)fname);
   if (p == NULL) {
     return retval;
   }
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index dff3b4223b..16a9b78c6a 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -9433,14 +9433,14 @@ static void ex_filetype(exarg_T *eap)
   }
   if (STRCMP(arg, "on") == 0 || STRCMP(arg, "detect") == 0) {
     if (*arg == 'o' || !filetype_detect) {
-      source_runtime((char_u *)FILETYPE_FILE, DIP_ALL);
+      source_runtime(FILETYPE_FILE, DIP_ALL);
       filetype_detect = kTrue;
       if (plugin) {
-        source_runtime((char_u *)FTPLUGIN_FILE, DIP_ALL);
+        source_runtime(FTPLUGIN_FILE, DIP_ALL);
         filetype_plugin = kTrue;
       }
       if (indent) {
-        source_runtime((char_u *)INDENT_FILE, DIP_ALL);
+        source_runtime(INDENT_FILE, DIP_ALL);
         filetype_indent = kTrue;
       }
     }
@@ -9451,15 +9451,15 @@ static void ex_filetype(exarg_T *eap)
   } else if (STRCMP(arg, "off") == 0) {
     if (plugin || indent) {
       if (plugin) {
-        source_runtime((char_u *)FTPLUGOF_FILE, DIP_ALL);
+        source_runtime(FTPLUGOF_FILE, DIP_ALL);
         filetype_plugin = kFalse;
       }
       if (indent) {
-        source_runtime((char_u *)INDOFF_FILE, DIP_ALL);
+        source_runtime(INDOFF_FILE, DIP_ALL);
         filetype_indent = kFalse;
       }
     } else {
-      source_runtime((char_u *)FTOFF_FILE, DIP_ALL);
+      source_runtime(FTOFF_FILE, DIP_ALL);
       filetype_detect = kFalse;
     }
   } else {
@@ -9471,15 +9471,15 @@ static void ex_filetype(exarg_T *eap)
 void filetype_maybe_enable(void)
 {
   if (filetype_detect == kNone) {
-    source_runtime((char_u *)FILETYPE_FILE, true);
+    source_runtime(FILETYPE_FILE, true);
     filetype_detect = kTrue;
   }
   if (filetype_plugin == kNone) {
-    source_runtime((char_u *)FTPLUGIN_FILE, true);
+    source_runtime(FTPLUGIN_FILE, true);
     filetype_plugin = kTrue;
   }
   if (filetype_indent == kNone) {
-    source_runtime((char_u *)INDENT_FILE, true);
+    source_runtime(INDENT_FILE, true);
     filetype_indent = kTrue;
   }
 }
diff --git a/src/nvim/ex_session.c b/src/nvim/ex_session.c
index 4aadd77d45..1e1da6a9a3 100644
--- a/src/nvim/ex_session.c
+++ b/src/nvim/ex_session.c
@@ -859,7 +859,7 @@ void ex_loadview(exarg_T *eap)
 {
   char *fname = get_view_file(*eap->arg);
   if (fname != NULL) {
-    if (do_source((char_u *)fname, false, DOSO_NONE) == FAIL) {
+    if (do_source(fname, false, DOSO_NONE) == FAIL) {
       EMSG2(_(e_notopen), fname);
     }
     xfree(fname);
diff --git a/src/nvim/file_search.c b/src/nvim/file_search.c
index d364895ea4..5458d8acf2 100644
--- a/src/nvim/file_search.c
+++ b/src/nvim/file_search.c
@@ -1664,13 +1664,13 @@ int vim_chdirfile(char_u *fname)
 /// Change directory to "new_dir". Search 'cdpath' for relative directory names.
 int vim_chdir(char_u *new_dir)
 {
-  char_u *dir_name = find_directory_in_path(new_dir, STRLEN(new_dir),
-                                            FNAME_MESS, curbuf->b_ffname);
+  char *dir_name = (char *)find_directory_in_path(new_dir, STRLEN(new_dir),
+                                                  FNAME_MESS, curbuf->b_ffname);
   if (dir_name == NULL) {
     return -1;
   }
 
-  int r = os_chdir((char *)dir_name);
+  int r = os_chdir(dir_name);
   xfree(dir_name);
   return r;
 }
diff --git a/src/nvim/fold.c b/src/nvim/fold.c
index 06b8049176..5a2ce74666 100644
--- a/src/nvim/fold.c
+++ b/src/nvim/fold.c
@@ -1838,8 +1838,7 @@ char_u *get_foldtext(win_T *wp, linenr_T lnum, linenr_T lnume, foldinfo_T foldin
       curbuf = wp->w_buffer;
 
       emsg_silent++;       // handle exceptions, but don't display errors
-      text = eval_to_string_safe(wp->w_p_fdt, NULL,
-                                 was_set_insecurely(wp, (char_u *)"foldtext", OPT_LOCAL));
+      text = eval_to_string_safe(wp->w_p_fdt, NULL, was_set_insecurely(wp, "foldtext", OPT_LOCAL));
       emsg_silent--;
 
       if (text == NULL || did_emsg) {
diff --git a/src/nvim/garray.c b/src/nvim/garray.c
index 69ad17ebcb..7a3cc4a944 100644
--- a/src/nvim/garray.c
+++ b/src/nvim/garray.c
@@ -143,14 +143,14 @@ void ga_remove_duplicate_strings(garray_T *gap)
 /// @param sep
 ///
 /// @returns the concatenated strings
-char_u *ga_concat_strings_sep(const garray_T *gap, const char *sep)
+char *ga_concat_strings_sep(const garray_T *gap, const char *sep)
   FUNC_ATTR_NONNULL_RET
 {
   const size_t nelem = (size_t)gap->ga_len;
   const char **strings = gap->ga_data;
 
   if (nelem == 0) {
-    return (char_u *)xstrdup("");
+    return xstrdup("");
   }
 
   size_t len = 0;
@@ -169,7 +169,7 @@ char_u *ga_concat_strings_sep(const garray_T *gap, const char *sep)
   }
   strcpy(s, strings[nelem - 1]);
 
-  return (char_u *)ret;
+  return ret;
 }
 
 /// For a growing array that contains a list of strings: concatenate all the
@@ -180,7 +180,7 @@ char_u *ga_concat_strings_sep(const garray_T *gap, const char *sep)
 /// @returns the concatenated strings
 char_u *ga_concat_strings(const garray_T *gap) FUNC_ATTR_NONNULL_RET
 {
-  return ga_concat_strings_sep(gap, ",");
+  return (char_u *)ga_concat_strings_sep(gap, ",");
 }
 
 /// Concatenate a string to a growarray which contains characters.
@@ -198,7 +198,7 @@ void ga_concat(garray_T *gap, const char *restrict s)
     return;
   }
 
-  ga_concat_len(gap, s, strlen((char *)s));
+  ga_concat_len(gap, s, STRLEN(s));
 }
 
 /// Concatenate a string to a growarray which contains characters
diff --git a/src/nvim/getchar.c b/src/nvim/getchar.c
index 280d2506c6..eb836b9005 100644
--- a/src/nvim/getchar.c
+++ b/src/nvim/getchar.c
@@ -2660,12 +2660,11 @@ void set_maparg_lhs_rhs(const char_u *orig_lhs, const size_t orig_lhs_len, const
   char_u *replaced = replace_termcodes(orig_lhs, orig_lhs_len, &lhs_buf,
                                        true, true, true, cpo_flags);
   mapargs->lhs_len = STRLEN(replaced);
-  xstrlcpy((char *)mapargs->lhs, (char *)replaced, sizeof(mapargs->lhs));
+  STRLCPY(mapargs->lhs, replaced, sizeof(mapargs->lhs));
 
   mapargs->orig_rhs_len = orig_rhs_len;
   mapargs->orig_rhs = xcalloc(mapargs->orig_rhs_len + 1, sizeof(char_u));
-  xstrlcpy((char *)mapargs->orig_rhs, (char *)orig_rhs,
-           mapargs->orig_rhs_len + 1);
+  STRLCPY(mapargs->orig_rhs, orig_rhs, mapargs->orig_rhs_len + 1);
 
   if (STRICMP(orig_rhs, "<nop>") == 0) {  // "<Nop>" means nothing
     mapargs->rhs = xcalloc(1, sizeof(char_u));  // single null-char
@@ -2677,7 +2676,7 @@ void set_maparg_lhs_rhs(const char_u *orig_lhs, const size_t orig_lhs_len, const
     mapargs->rhs_len = STRLEN(replaced);
     mapargs->rhs_is_noop = false;
     mapargs->rhs = xcalloc(mapargs->rhs_len + 1, sizeof(char_u));
-    xstrlcpy((char *)mapargs->rhs, (char *)replaced, mapargs->rhs_len + 1);
+    STRLCPY(mapargs->rhs, replaced, mapargs->rhs_len + 1);
   }
 
   xfree(lhs_buf);
@@ -2785,7 +2784,7 @@ int str_to_mapargs(const char_u *strargs, bool is_unmap, MapArguments *mapargs)
   // (e.g. "<Space>" is longer than ' '), so first copy into a buffer.
   size_t orig_lhs_len = (size_t)(lhs_end - to_parse);
   char_u *lhs_to_replace = xcalloc(orig_lhs_len + 1, sizeof(char_u));
-  xstrlcpy((char *)lhs_to_replace, (char *)to_parse, orig_lhs_len + 1);
+  STRLCPY(lhs_to_replace, to_parse, orig_lhs_len + 1);
 
   size_t orig_rhs_len = STRLEN(rhs_start);
   set_maparg_lhs_rhs(lhs_to_replace, orig_lhs_len,
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 182e88083a..1d120bbe6b 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -669,7 +669,7 @@ EXTERN bool swap_exists_did_quit INIT(= false);
 
 EXTERN char_u IObuff[IOSIZE];               ///< Buffer for sprintf, I/O, etc.
 EXTERN char_u NameBuff[MAXPATHL];           ///< Buffer for expanding file names
-EXTERN char_u msg_buf[MSG_BUF_LEN];         ///< Small buffer for messages
+EXTERN char msg_buf[MSG_BUF_LEN];           ///< Small buffer for messages
 EXTERN char os_buf[                         ///< Buffer for the os/ layer
 #if MAXPATHL > IOSIZE
                                             MAXPATHL
@@ -982,9 +982,8 @@ EXTERN char_u e_float_as_string[] INIT(= N_("E806: using Float as a String"));
 
 EXTERN char_u e_autocmd_err[] INIT(=N_("E5500: autocmd has thrown an exception: %s"));
 EXTERN char_u e_cmdmap_err[] INIT(=N_("E5520: <Cmd> mapping must end with <CR>"));
-EXTERN char_u e_cmdmap_repeated[] INIT(=
-                                         N_(
-                                          "E5521: <Cmd> mapping must end with <CR> before second <Cmd>"));
+EXTERN char_u
+e_cmdmap_repeated[] INIT(=N_("E5521: <Cmd> mapping must end with <CR> before second <Cmd>"));
 EXTERN char_u e_cmdmap_key[] INIT(=N_("E5522: <Cmd> mapping must not include %s key"));
 
 EXTERN char_u e_api_error[] INIT(=N_("E5555: API call: %s"));
diff --git a/src/nvim/hardcopy.c b/src/nvim/hardcopy.c
index 9d9ffa550a..99e0bff81c 100644
--- a/src/nvim/hardcopy.c
+++ b/src/nvim/hardcopy.c
@@ -551,7 +551,7 @@ static void prt_header(prt_settings_T *const psettings, const int pagenum, const
     curwin->w_botline = lnum + 63;
     printer_page_num = pagenum;
 
-    use_sandbox = was_set_insecurely(curwin, (char_u *)"printheader", 0);
+    use_sandbox = was_set_insecurely(curwin, "printheader", 0);
     build_stl_str_hl(curwin, tbuf, (size_t)width + IOSIZE,
                      p_header, use_sandbox,
                      ' ', width, NULL, NULL);
diff --git a/src/nvim/indent.c b/src/nvim/indent.c
index a3ee3983e5..f49aff6643 100644
--- a/src/nvim/indent.c
+++ b/src/nvim/indent.c
@@ -533,7 +533,7 @@ int get_expr_indent(void)
   colnr_T save_curswant;
   int save_set_curswant;
   int save_State;
-  int use_sandbox = was_set_insecurely(curwin, (char_u *)"indentexpr", OPT_LOCAL);
+  int use_sandbox = was_set_insecurely(curwin, "indentexpr", OPT_LOCAL);
 
   // Save and restore cursor position and curswant, in case it was changed
   // * via :normal commands.
diff --git a/src/nvim/main.c b/src/nvim/main.c
index 069c253bff..9a82eccc6f 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -1700,7 +1700,7 @@ static void do_system_initialization(void)
       memcpy(vimrc, dir, dir_len);
       vimrc[dir_len] = PATHSEP;
       memcpy(vimrc + dir_len + 1, path_tail, sizeof(path_tail));
-      if (do_source((char_u *)vimrc, false, DOSO_NONE) != FAIL) {
+      if (do_source(vimrc, false, DOSO_NONE) != FAIL) {
         xfree(vimrc);
         xfree(config_dirs);
         return;
@@ -1712,7 +1712,7 @@ static void do_system_initialization(void)
 
 #ifdef SYS_VIMRC_FILE
   // Get system wide defaults, if the file name is defined.
-  (void)do_source((char_u *)SYS_VIMRC_FILE, false, DOSO_NONE);
+  (void)do_source(SYS_VIMRC_FILE, false, DOSO_NONE);
 #endif
 }
 
@@ -1741,7 +1741,7 @@ static bool do_user_initialization(void)
 
   // init.lua
   if (os_path_exists(init_lua_path)
-      && do_source(init_lua_path, true, DOSO_VIMRC)) {
+      && do_source((char *)init_lua_path, true, DOSO_VIMRC)) {
     if (os_path_exists(user_vimrc)) {
       EMSG3(_("E5422: Conflicting configs: \"%s\" \"%s\""), init_lua_path,
             user_vimrc);
@@ -1754,7 +1754,7 @@ static bool do_user_initialization(void)
   xfree(init_lua_path);
 
   // init.vim
-  if (do_source(user_vimrc, true, DOSO_VIMRC) != FAIL) {
+  if (do_source((char *)user_vimrc, true, DOSO_VIMRC) != FAIL) {
     do_exrc = p_exrc;
     if (do_exrc) {
       do_exrc = (path_full_compare((char_u *)VIMRC_FILE, user_vimrc,
@@ -1782,7 +1782,7 @@ static bool do_user_initialization(void)
       memmove(vimrc, dir, dir_len);
       vimrc[dir_len] = PATHSEP;
       memmove(vimrc + dir_len + 1, path_tail, sizeof(path_tail));
-      if (do_source((char_u *)vimrc, true, DOSO_VIMRC) != FAIL) {
+      if (do_source(vimrc, true, DOSO_VIMRC) != FAIL) {
         do_exrc = p_exrc;
         if (do_exrc) {
           do_exrc = (path_full_compare((char_u *)VIMRC_FILE, (char_u *)vimrc,
@@ -1814,7 +1814,7 @@ static void source_startup_scripts(const mparm_T *const parmp)
         || strequal(parmp->use_vimrc, "NORC")) {
       // Do nothing.
     } else {
-      if (do_source((char_u *)parmp->use_vimrc, false, DOSO_NONE) != OK) {
+      if (do_source(parmp->use_vimrc, false, DOSO_NONE) != OK) {
         EMSG2(_("E282: Cannot read from \"%s\""), parmp->use_vimrc);
       }
     }
@@ -1835,7 +1835,7 @@ static void source_startup_scripts(const mparm_T *const parmp)
 #endif
       secure = p_secure;
 
-      if (do_source((char_u *)VIMRC_FILE, true, DOSO_VIMRC) == FAIL) {
+      if (do_source(VIMRC_FILE, true, DOSO_VIMRC) == FAIL) {
 #if defined(UNIX)
         // if ".exrc" is not owned by user set 'secure' mode
         if (!file_owned(EXRC_FILE)) {
@@ -1844,7 +1844,7 @@ static void source_startup_scripts(const mparm_T *const parmp)
           secure = 0;
         }
 #endif
-        (void)do_source((char_u *)EXRC_FILE, false, DOSO_NONE);
+        (void)do_source(EXRC_FILE, false, DOSO_NONE);
       }
     }
     if (secure == 2) {
diff --git a/src/nvim/misc1.c b/src/nvim/misc1.c
index 2dfe5df325..40db5b7cf3 100644
--- a/src/nvim/misc1.c
+++ b/src/nvim/misc1.c
@@ -696,18 +696,18 @@ void msgmore(long n)
       }
     } else {
       if (n > 0) {
-        vim_snprintf((char *)msg_buf, MSG_BUF_LEN,
+        vim_snprintf(msg_buf, MSG_BUF_LEN,
                      _("%" PRId64 " more lines"), (int64_t)pn);
       } else {
-        vim_snprintf((char *)msg_buf, MSG_BUF_LEN,
+        vim_snprintf(msg_buf, MSG_BUF_LEN,
                      _("%" PRId64 " fewer lines"), (int64_t)pn);
       }
     }
     if (got_int) {
-      xstrlcat((char *)msg_buf, _(" (Interrupted)"), MSG_BUF_LEN);
+      xstrlcat(msg_buf, _(" (Interrupted)"), MSG_BUF_LEN);
     }
-    if (msg(msg_buf)) {
-      set_keep_msg(msg_buf, 0);
+    if (msg((char_u *)msg_buf)) {
+      set_keep_msg((char_u *)msg_buf, 0);
       keep_msg_more = true;
     }
   }
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 0668924237..8bc2b3781a 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -4253,7 +4253,7 @@ void op_formatexpr(oparg_T *oap)
 /// @param c  character to be inserted
 int fex_format(linenr_T lnum, long count, int c)
 {
-  int use_sandbox = was_set_insecurely(curwin, (char_u *)"formatexpr", OPT_LOCAL);
+  int use_sandbox = was_set_insecurely(curwin, "formatexpr", OPT_LOCAL);
   int r;
   char_u *fex;
 
@@ -4817,7 +4817,7 @@ void op_addsub(oparg_T *oap, linenr_T Prenum1, bool g_cmd)
       if (change_cnt == 1) {
         MSG(_("1 line changed"));
       } else {
-        smsg((char *)_("%" PRId64 " lines changed"), (int64_t)change_cnt);
+        smsg(_("%" PRId64 " lines changed"), (int64_t)change_cnt);
       }
     }
   }
@@ -6056,7 +6056,7 @@ bool prepare_yankreg_from_object(yankreg_T *reg, String regtype, size_t lines)
 
 void finish_yankreg_from_object(yankreg_T *reg, bool clipboard_adjust)
 {
-  if (reg->y_size > 0 && strlen((char *)reg->y_array[reg->y_size-1]) == 0) {
+  if (reg->y_size > 0 && STRLEN(reg->y_array[reg->y_size-1]) == 0) {
     // a known-to-be charwise yank might have a final linebreak
     // but otherwise there is no line after the final newline
     if (reg->y_type != kMTCharWise) {
@@ -6121,7 +6121,7 @@ static bool get_clipboard(int name, yankreg_T **target, bool quiet)
       goto err;
     }
     char_u *regtype = TV_LIST_ITEM_TV(tv_list_last(res))->vval.v_string;
-    if (regtype == NULL || strlen((char *)regtype) > 1) {
+    if (regtype == NULL || STRLEN(regtype) > 1) {
       goto err;
     }
     switch (regtype[0]) {
@@ -6164,7 +6164,7 @@ static bool get_clipboard(int name, yankreg_T **target, bool quiet)
     reg->y_array[tv_idx++] = (char_u *)xstrdupnul((const char *)TV_LIST_ITEM_TV(li)->vval.v_string);
   });
 
-  if (reg->y_size > 0 && strlen((char *)reg->y_array[reg->y_size-1]) == 0) {
+  if (reg->y_size > 0 && STRLEN(reg->y_array[reg->y_size-1]) == 0) {
     // a known-to-be charwise yank might have a final linebreak
     // but otherwise there is no line after the final newline
     if (reg->y_type != kMTCharWise) {
diff --git a/src/nvim/option.c b/src/nvim/option.c
index b766ae92cf..659e16268b 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -2072,9 +2072,9 @@ static void check_string_option(char_u **pp)
 /// Return true when option "opt" was set from a modeline or in secure mode.
 /// Return false when it wasn't.
 /// Return -1 for an unknown option.
-int was_set_insecurely(win_T *const wp, char_u *opt, int opt_flags)
+int was_set_insecurely(win_T *const wp, char *opt, int opt_flags)
 {
-  int idx = findoption((const char *)opt);
+  int idx = findoption(opt);
 
   if (idx >= 0) {
     uint32_t *flagp = insecure_flag(wp, idx, opt_flags);
@@ -3288,7 +3288,7 @@ ambw_end:
       if (p > q) {
         vim_snprintf((char *)fname, sizeof(fname), "spell/%.*s.vim",
                      (int)(p - q), q);
-        source_runtime(fname, DIP_ALL);
+        source_runtime((char *)fname, DIP_ALL);
       }
     }
   }
diff --git a/src/nvim/path.c b/src/nvim/path.c
index 60c7ea7fa4..5b1793b111 100644
--- a/src/nvim/path.c
+++ b/src/nvim/path.c
@@ -1658,8 +1658,7 @@ static char *eval_includeexpr(const char *const ptr, const size_t len)
 {
   set_vim_var_string(VV_FNAME, ptr, (ptrdiff_t)len);
   char *res = (char *)eval_to_string_safe(curbuf->b_p_inex, NULL,
-                                          was_set_insecurely(curwin, (char_u *)"includeexpr",
-                                                             OPT_LOCAL));
+                                          was_set_insecurely(curwin, "includeexpr", OPT_LOCAL));
   set_vim_var_string(VV_FNAME, NULL, 0);
   return res;
 }
@@ -2038,7 +2037,7 @@ char_u *path_shorten_fname(char_u *full_path, char_u *dir_name)
   }
 
   assert(dir_name != NULL);
-  size_t len = strlen((char *)dir_name);
+  size_t len = STRLEN(dir_name);
 
   // If dir_name is a path head, full_path can always be made relative.
   if (len == (size_t)path_head_length() && is_path_head(dir_name)) {
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index 046e6dbd12..53be2c04e2 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -1628,8 +1628,8 @@ static int qf_parse_multiline_pfx(int idx, qf_list_T *qfl, qffields_T *fields)
       return QF_FAIL;
     }
     if (*fields->errmsg) {
-      size_t textlen = strlen((char *)qfprev->qf_text);
-      size_t errlen  = strlen((char *)fields->errmsg);
+      size_t textlen = STRLEN(qfprev->qf_text);
+      size_t errlen  = STRLEN(fields->errmsg);
       qfprev->qf_text = xrealloc(qfprev->qf_text, textlen + errlen + 2);
       qfprev->qf_text[textlen] = '\n';
       STRCPY(qfprev->qf_text + textlen + 1, fields->errmsg);
diff --git a/src/nvim/runtime.c b/src/nvim/runtime.c
index c47bffd426..67df0c9258 100644
--- a/src/nvim/runtime.c
+++ b/src/nvim/runtime.c
@@ -47,13 +47,13 @@ void ex_runtime(exarg_T *eap)
     arg = skipwhite(arg + len);
   }
 
-  source_runtime(arg, flags);
+  source_runtime((char *)arg, flags);
 }
 
 
 static void source_callback(char_u *fname, void *cookie)
 {
-  (void)do_source(fname, false, DOSO_NONE);
+  (void)do_source((char *)fname, false, DOSO_NONE);
 }
 
 /// Find the file "name" in all directories in "path" and invoke
@@ -64,7 +64,7 @@ static void source_callback(char_u *fname, void *cookie)
 /// When "flags" has DIP_ERR: give an error message if there is no match.
 ///
 /// return FAIL when no file could be sourced, OK otherwise.
-int do_in_path(char_u *path, char_u *name, int flags, DoInRuntimepathCB callback, void *cookie)
+int do_in_path(char_u *path, char *name, int flags, DoInRuntimepathCB callback, void *cookie)
 {
   char_u *tail;
   int num_files;
@@ -79,8 +79,7 @@ int do_in_path(char_u *path, char_u *name, int flags, DoInRuntimepathCB callback
   {
     if (p_verbose > 10 && name != NULL) {
       verbose_enter();
-      smsg(_("Searching for \"%s\" in \"%s\""),
-           (char *)name, (char *)path);
+      smsg(_("Searching for \"%s\" in \"%s\""), name, (char *)path);
       verbose_leave();
     }
 
@@ -109,7 +108,7 @@ int do_in_path(char_u *path, char_u *name, int flags, DoInRuntimepathCB callback
         tail = buf + STRLEN(buf);
 
         // Loop over all patterns in "name"
-        char_u *np = name;
+        char_u *np = (char_u *)name;
         while (*np != NUL && ((flags & DIP_ALL) || !did_one)) {
           // Append the pattern from "name" to buf[].
           assert(MAXPATHL >= (tail - buf));
@@ -281,16 +280,16 @@ int do_in_path_and_pp(char_u *path, char_u *name, int flags, DoInRuntimepathCB c
   int done = FAIL;
 
   if ((flags & DIP_NORTP) == 0) {
-    done |= do_in_path(path, (name && !*name) ? NULL : name, flags, callback, cookie);
+    done |= do_in_path(path, (char *)((name && !*name) ? NULL : name), flags, callback, cookie);
   }
 
   if ((done == FAIL || (flags & DIP_ALL)) && (flags & DIP_START)) {
     char *start_dir = "pack/*/start/*/%s%s";  // NOLINT
     size_t len = STRLEN(start_dir) + STRLEN(name) + 6;
-    char_u *s = xmallocz(len);  // TODO(bfredl): get rid of random allocations
+    char *s = xmallocz(len);  // TODO(bfredl): get rid of random allocations
     char *suffix = (flags & DIP_AFTER) ? "after/" : "";
 
-    vim_snprintf((char *)s, len, start_dir, suffix, name);
+    vim_snprintf(s, len, start_dir, suffix, name);
     done |= do_in_path(p_pp, s, flags & ~DIP_AFTER, callback, cookie);
 
     xfree(s);
@@ -300,7 +299,7 @@ int do_in_path_and_pp(char_u *path, char_u *name, int flags, DoInRuntimepathCB c
       len = STRLEN(start_dir) + STRLEN(name) + 6;
       s = xmallocz(len);
 
-      vim_snprintf((char *)s, len, start_dir, suffix, name);
+      vim_snprintf(s, len, start_dir, suffix, name);
       done |= do_in_path(p_pp, s, flags & ~DIP_AFTER, callback, cookie);
 
       xfree(s);
@@ -310,9 +309,9 @@ int do_in_path_and_pp(char_u *path, char_u *name, int flags, DoInRuntimepathCB c
   if ((done == FAIL || (flags & DIP_ALL)) && (flags & DIP_OPT)) {
     char *opt_dir = "pack/*/opt/*/%s";  // NOLINT
     size_t len = STRLEN(opt_dir) + STRLEN(name);
-    char_u *s = xmallocz(len);
+    char *s = xmallocz(len);
 
-    vim_snprintf((char *)s, len, opt_dir, name);
+    vim_snprintf(s, len, opt_dir, name);
     done |= do_in_path(p_pp, s, flags, callback, cookie);
 
     xfree(s);
@@ -322,7 +321,7 @@ int do_in_path_and_pp(char_u *path, char_u *name, int flags, DoInRuntimepathCB c
       len = STRLEN(opt_dir) + STRLEN(name);
       s = xmallocz(len);
 
-      vim_snprintf((char *)s, len, opt_dir, name);
+      vim_snprintf(s, len, opt_dir, name);
       done |= do_in_path(p_pp, s, flags, callback, cookie);
 
       xfree(s);
@@ -374,7 +373,7 @@ static void expand_pack_entry(RuntimeSearchPath *search_path, Map(String, handle
     if (STRLEN(pack_entry) + STRLEN(start_pat[i]) + 1 > MAXPATHL) {
       continue;
     }
-    xstrlcpy(buf, (char *)pack_entry, MAXPATHL);
+    STRLCPY(buf, pack_entry, MAXPATHL);
     xstrlcat(buf, start_pat[i], sizeof buf);
     expand_rtp_entry(search_path, rtp_used, buf, false);
     size_t after_size = STRLEN(buf)+7;
@@ -515,9 +514,9 @@ int do_in_runtimepath(char_u *name, int flags, DoInRuntimepathCB callback, void
 /// When "flags" has DIP_ALL: source all files, otherwise only the first one.
 ///
 /// return FAIL when no file could be sourced, OK otherwise.
-int source_runtime(char_u *name, int flags)
+int source_runtime(char *name, int flags)
 {
-  return do_in_runtimepath(name, flags, source_callback, NULL);
+  return do_in_runtimepath((char_u *)name, flags, source_callback, NULL);
 }
 
 /// Just like source_runtime(), but use "path" instead of 'runtimepath'.
@@ -535,7 +534,7 @@ static void source_all_matches(char_u *pat)
 
   if (gen_expand_wildcards(1, &pat, &num_files, &files, EW_FILE) == OK) {
     for (int i = 0; i < num_files; i++) {
-      (void)do_source(files[i], false, DOSO_NONE);
+      (void)do_source((char *)files[i], false, DOSO_NONE);
     }
     FreeWild(num_files, files);
   }
@@ -791,7 +790,7 @@ static void add_pack_start_dir(char_u *fname, void *cookie)
     if (STRLEN(fname) + STRLEN(start_pat[i]) + 1 > MAXPATHL) {
       continue;
     }
-    xstrlcpy((char *)buf, (char *)fname, MAXPATHL);
+    STRLCPY(buf, fname, MAXPATHL);
     xstrlcat((char *)buf, start_pat[i], sizeof buf);
     if (pack_has_entries(buf)) {
       add_pack_dir_to_rtp(buf, true);
@@ -804,9 +803,9 @@ static void add_pack_start_dir(char_u *fname, void *cookie)
 void load_start_packages(void)
 {
   did_source_packages = true;
-  do_in_path(p_pp, (char_u *)"pack/*/start/*", DIP_ALL + DIP_DIR,  // NOLINT
+  do_in_path(p_pp, "pack/*/start/*", DIP_ALL + DIP_DIR,  // NOLINT
              add_start_pack_plugin, &APP_LOAD);
-  do_in_path(p_pp, (char_u *)"start/*", DIP_ALL + DIP_DIR,  // NOLINT
+  do_in_path(p_pp, "start/*", DIP_ALL + DIP_DIR,  // NOLINT
              add_start_pack_plugin, &APP_LOAD);
 }
 
@@ -849,8 +848,8 @@ void load_plugins(void)
     }
     TIME_MSG("loading packages");
 
-    source_runtime(plugin_pattern_vim, DIP_ALL | DIP_AFTER);
-    source_runtime(plugin_pattern_lua, DIP_ALL | DIP_AFTER);
+    source_runtime((char *)plugin_pattern_vim, DIP_ALL | DIP_AFTER);
+    source_runtime((char *)plugin_pattern_lua, DIP_ALL | DIP_AFTER);
     TIME_MSG("loading after plugins");
   }
 }
@@ -873,9 +872,7 @@ void ex_packadd(exarg_T *eap)
     vim_snprintf(pat, len, plugpat, round == 1 ? "start" : "opt", eap->arg);
     // The first round don't give a "not found" error, in the second round
     // only when nothing was found in the first round.
-    res = do_in_path(p_pp, (char_u *)pat,
-                     DIP_ALL + DIP_DIR
-                     + (round == 2 && res == FAIL ? DIP_ERR : 0),
+    res = do_in_path(p_pp, pat, DIP_ALL + DIP_DIR + (round == 2 && res == FAIL ? DIP_ERR : 0),
                      round == 1 ? add_start_pack_plugin : add_opt_pack_plugin,
                      eap->forceit ? &APP_ADD_DIR : &APP_BOTH);
     xfree(pat);
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index d8cd8c2008..0bd9dbe0d5 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -5465,7 +5465,7 @@ static void win_redr_custom(win_T *wp, bool draw_ruler)
     fillchar = ' ';
     attr = HL_ATTR(HLF_TPF);
     maxwidth = Columns;
-    use_sandbox = was_set_insecurely(wp, (char_u *)"tabline", 0);
+    use_sandbox = was_set_insecurely(wp, "tabline", 0);
   } else {
     row = W_ENDROW(wp);
     fillchar = fillchar_status(&attr, wp);
@@ -5500,15 +5500,14 @@ static void win_redr_custom(win_T *wp, bool draw_ruler)
         attr = HL_ATTR(HLF_MSG);
       }
 
-      use_sandbox = was_set_insecurely(wp, (char_u *)"rulerformat", 0);
+      use_sandbox = was_set_insecurely(wp, "rulerformat", 0);
     } else {
       if (*wp->w_p_stl != NUL) {
         stl = wp->w_p_stl;
       } else {
         stl = p_stl;
       }
-      use_sandbox = was_set_insecurely(wp, (char_u *)"statusline",
-                                       *wp->w_p_stl == NUL ? 0 : OPT_LOCAL);
+      use_sandbox = was_set_insecurely(wp, "statusline", *wp->w_p_stl == NUL ? 0 : OPT_LOCAL);
     }
 
     col += wp->w_wincol;
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index 2b5faee8de..ac4c81f6b3 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -4393,8 +4393,8 @@ static void syn_cmd_include(exarg_T *eap, int syncing)
   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) == FAIL
-      : source_runtime(eap->arg, DIP_ALL) == FAIL) {
+      ? do_source((char *)eap->arg, false, DOSO_NONE) == FAIL
+      : source_runtime((char *)eap->arg, DIP_ALL) == FAIL) {
     EMSG2(_(e_notopen), eap->arg);
   }
   curwin->w_s->b_syn_topgrp = prev_toplvl_grp;
@@ -6616,10 +6616,10 @@ int load_colors(char_u *name)
   buf = xmalloc(buflen);
   apply_autocmds(EVENT_COLORSCHEMEPRE, name, curbuf->b_fname, false, curbuf);
   snprintf((char *)buf, buflen, "colors/%s.vim", name);
-  retval = source_runtime(buf, DIP_START + DIP_OPT);
+  retval = source_runtime((char *)buf, DIP_START + DIP_OPT);
   if (retval == FAIL) {
     snprintf((char *)buf, buflen, "colors/%s.lua", name);
-    retval = source_runtime(buf, DIP_START + DIP_OPT);
+    retval = source_runtime((char *)buf, DIP_START + DIP_OPT);
   }
   xfree(buf);
   apply_autocmds(EVENT_COLORSCHEME, name, curbuf->b_fname, false, curbuf);
diff --git a/src/nvim/tag.c b/src/nvim/tag.c
index 768cca284b..ee92a2c642 100644
--- a/src/nvim/tag.c
+++ b/src/nvim/tag.c
@@ -906,7 +906,7 @@ static int add_llist_tags(char_u *tag, int num_matches, char_u **matches)
     if (len > 128) {
       len = 128;
     }
-    xstrlcpy((char *)tag_name, (const char *)tagp.tagname, len + 1);
+    STRLCPY(tag_name, tagp.tagname, len + 1);
     tag_name[len] = NUL;
 
     // Save the tag file name
@@ -914,7 +914,7 @@ static int add_llist_tags(char_u *tag, int num_matches, char_u **matches)
     if (p == NULL) {
       continue;
     }
-    xstrlcpy((char *)fname, (const char *)p, MAXPATHL);
+    STRLCPY(fname, p, MAXPATHL);
     XFREE_CLEAR(p);
 
     // Get the line number or the search pattern used to locate