refactor: reduce number of explicit char casts (#16077)

* refactor: reduce number of explicit char casts

3 files changed, 8 insertions, 10 deletions

diff --git a/src/nvim/eval/encode.c b/src/nvim/eval/encode.c
index b457353838..d694b8a374 100644
--- a/src/nvim/eval/encode.c
+++ b/src/nvim/eval/encode.c
@@ -29,8 +29,6 @@
 #include "nvim/message.h"
 #include "nvim/vim.h"  // For _()
 
-#define utf_ptr2char(b) utf_ptr2char((char_u *)b)
-#define utf_ptr2len(b) ((size_t)utf_ptr2len((char_u *)b))
 #define utf_char2len(b) ((size_t)utf_char2len(b))
 
 const char *const encode_bool_var_names[] = {
@@ -614,8 +612,8 @@ static inline int convert_to_json_string(garray_T *const gap, const char *const
 #define ENCODE_RAW(ch) \
   (ch >= 0x20 && utf_printable(ch))
     for (size_t i = 0; i < utf_len;) {
-      const int ch = utf_ptr2char(utf_buf + i);
-      const size_t shift = (ch == 0? 1: utf_ptr2len(utf_buf + i));
+      const int ch = utf_ptr2char((char_u *)utf_buf + i);
+      const size_t shift = (ch == 0 ? 1 : ((size_t)utf_ptr2len((char_u *)utf_buf + i)));
       assert(shift > 0);
       i += shift;
       switch (ch) {
@@ -654,11 +652,11 @@ static inline int convert_to_json_string(garray_T *const gap, const char *const
     ga_append(gap, '"');
     ga_grow(gap, (int)str_len);
     for (size_t i = 0; i < utf_len;) {
-      const int ch = utf_ptr2char(utf_buf + i);
+      const int ch = utf_ptr2char((char_u *)utf_buf + i);
       const size_t shift = (ch == 0? 1: utf_char2len(ch));
       assert(shift > 0);
       // Is false on invalid unicode, but this should already be handled.
-      assert(ch == 0 || shift == utf_ptr2len(utf_buf + i));
+      assert(ch == 0 || shift == ((size_t)utf_ptr2len((char_u *)utf_buf + i)));
       switch (ch) {
       case BS:
       case TAB:
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 1d9ebdb596..7549ec7ac8 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -3544,7 +3544,7 @@ static void f_getcwd(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 
   if (from) {
-    xstrlcpy((char *)cwd, (char *)from, MAXPATHL);
+    STRLCPY(cwd, from, MAXPATHL);
   }
 
   rettv->vval.v_string = vim_strsave(cwd);
@@ -4867,7 +4867,7 @@ static void f_histnr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
  */
 static void f_hlID(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
-  rettv->vval.v_number = syn_name2id((const char_u *)tv_get_string(&argvars[0]));
+  rettv->vval.v_number = syn_name2id(tv_get_string(&argvars[0]));
 }
 
 /*
@@ -4875,7 +4875,7 @@ static void f_hlID(typval_T *argvars, typval_T *rettv, FunPtr fptr)
  */
 static void f_hlexists(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
-  rettv->vval.v_number = highlight_exists((const char_u *)tv_get_string(&argvars[0]));
+  rettv->vval.v_number = highlight_exists(tv_get_string(&argvars[0]));
 }
 
 /*
diff --git a/src/nvim/eval/userfunc.c b/src/nvim/eval/userfunc.c
index 6fe75e5e1f..80a22f6f9d 100644
--- a/src/nvim/eval/userfunc.c
+++ b/src/nvim/eval/userfunc.c
@@ -1818,7 +1818,7 @@ char_u *trans_function_name(char_u **pp, bool skip, int flags, funcdict_T *fdp,
   if (name != NULL) {
     name = vim_strsave(name);
     *pp = (char_u *)end;
-    if (strncmp((char *)name, "<SNR>", 5) == 0) {
+    if (STRNCMP(name, "<SNR>", 5) == 0) {
       // Change "<SNR>" to the byte sequence.
       name[0] = K_SPECIAL;
       name[1] = KS_EXTRA;