Use type checking `mrb_to_str` instead of converting `mrb_str_to_str`.

include/mruby/string.h

@@ -352,6 +352,7 @@ MRB_API double mrb_str_to_dbl(mrb_state *mrb, mrb_value str, mrb_bool badcheck);
 
 /*
  * Returns a converted string type.
+ * For type checking, non converting `mrb_to_str` is recommended.
  */
 MRB_API mrb_value mrb_str_to_str(mrb_state *mrb, mrb_value str);
 

mrbgems/mruby-sprintf/src/sprintf.c

@@ -552,7 +552,7 @@ mrb_str_format(mrb_state *mrb, mrb_int argc, const mrb_value *argv, mrb_value fm
 
   ++argc;
   --argv;
-  fmt = mrb_str_to_str(mrb, fmt);
+  mrb_to_str(mrb, fmt);
   p = RSTRING_PTR(fmt);
   end = p + RSTRING_LEN(fmt);
   blen = 0;

mrbgems/mruby-struct/src/struct.c

@@ -213,7 +213,7 @@ make_struct(mrb_state *mrb, mrb_value name, mrb_value members, struct RClass *kl
   }
   else {
     /* old style: should we warn? */
-    name = mrb_str_to_str(mrb, name);
+    mrb_to_str(mrb, name);
     id = mrb_obj_to_sym(mrb, name);
     if (!is_const_id(mrb, mrb_sym2name_len(mrb, id, NULL))) {
       mrb_name_error(mrb, id, "identifier %S needs to be constant", name);

src/error.c

@@ -28,7 +28,7 @@ mrb_exc_new(mrb_state *mrb, struct RClass *c, const char *ptr, size_t len)
 MRB_API mrb_value
 mrb_exc_new_str(mrb_state *mrb, struct RClass* c, mrb_value str)
 {
-  str = mrb_str_to_str(mrb, str);
+  mrb_to_str(mrb, str);
   return mrb_obj_new(mrb, c, 1, &str);
 }
 

src/string.c

@@ -748,9 +748,7 @@ mrb_str_to_cstr(mrb_state *mrb, mrb_value str0)
 MRB_API void
 mrb_str_concat(mrb_state *mrb, mrb_value self, mrb_value other)
 {
-  if (!mrb_string_p(other)) {
-    other = mrb_str_to_str(mrb, other);
-  }
+  other = mrb_str_to_str(mrb, other);
   mrb_str_cat_str(mrb, self, other);
 }
 
@@ -993,15 +991,15 @@ mrb_str_to_str(mrb_state *mrb, mrb_value str)
 MRB_API const char*
 mrb_string_value_ptr(mrb_state *mrb, mrb_value ptr)
 {
-  mrb_value str = mrb_str_to_str(mrb, ptr);
-  return RSTRING_PTR(str);
+  mrb_to_str(mrb, ptr);
+  return RSTRING_PTR(ptr);
 }
 
 MRB_API mrb_int
 mrb_string_value_len(mrb_state *mrb, mrb_value ptr)
 {
-  mrb_value str = mrb_str_to_str(mrb, ptr);
-  return RSTRING_LEN(str);
+  mrb_to_str(mrb, ptr);
+  return RSTRING_LEN(ptr);
 }
 
 void
@@ -2183,7 +2181,7 @@ mrb_cstr_to_inum(mrb_state *mrb, const char *str, int base, int badcheck)
 MRB_API const char*
 mrb_string_value_cstr(mrb_state *mrb, mrb_value *ptr)
 {
-  mrb_value str = mrb_str_to_str(mrb, *ptr);
+  mrb_value str = mrb_to_str(mrb, *ptr);
   struct RString *ps = mrb_str_ptr(str);
   mrb_int len = mrb_str_strlen(mrb, ps);
   char *p = RSTR_PTR(ps);
@@ -2313,7 +2311,7 @@ mrb_str_to_dbl(mrb_state *mrb, mrb_value str, mrb_bool badcheck)
   char *s;
   mrb_int len;
 
-  str = mrb_str_to_str(mrb, str);
+  mrb_to_str(mrb, str);
   s = RSTRING_PTR(str);
   len = RSTRING_LEN(str);
   if (s) {
@@ -2600,7 +2598,7 @@ mrb_str_cat_str(mrb_state *mrb, mrb_value str, mrb_value str2)
 MRB_API mrb_value
 mrb_str_append(mrb_state *mrb, mrb_value str1, mrb_value str2)
 {
-  str2 = mrb_str_to_str(mrb, str2);
+  mrb_to_str(mrb, str2);
   return mrb_str_cat_str(mrb, str1, str2);
 }