fixup! Remove implicit conversion using `to_str` method.

include/mruby/string.h

@@ -311,8 +311,7 @@ MRB_API mrb_value mrb_str_substr(mrb_state *mrb, mrb_value str, mrb_int beg, mrb
  * @param [mrb_value] str Ruby string.
  * @return [mrb_value] A Ruby string.
  */
-MRB_API mrb_value mrb_string_type(mrb_state *mrb, mrb_value str);
-
+MRB_API mrb_value mrb_ensure_string_type(mrb_state *mrb, mrb_value str);
 MRB_API mrb_value mrb_check_string_type(mrb_state *mrb, mrb_value str);
 MRB_API mrb_value mrb_str_new_capa(mrb_state *mrb, size_t capa);
 MRB_API mrb_value mrb_str_buf_new(mrb_state *mrb, size_t capa);

mrbgems/mruby-io/src/file.c

@@ -115,7 +115,7 @@ mrb_file_s_unlink(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "*", &argv, &argc);
   for (i = 0; i < argc; i++) {
     const char *utf8_path;
-    pathv = mrb_string_type(mrb, argv[i]);
+    pathv = mrb_ensure_string_type(mrb, argv[i]);
     utf8_path = mrb_string_value_cstr(mrb, &pathv);
     path = mrb_locale_from_utf8(utf8_path, -1);
     if (UNLINK(path) < 0) {

mrbgems/mruby-string-ext/src/string.c

@@ -163,7 +163,7 @@ mrb_str_concat_m(mrb_state *mrb, mrb_value self)
   if (mrb_fixnum_p(str))
     str = mrb_fixnum_chr(mrb, str);
   else
-    str = mrb_string_type(mrb, str);
+    str = mrb_ensure_string_type(mrb, str);
   mrb_str_concat(mrb, self, str);
   return self;
 }
@@ -191,7 +191,7 @@ mrb_str_start_with(mrb_state *mrb, mrb_value self)
   for (i = 0; i < argc; i++) {
     size_t len_l, len_r;
     int ai = mrb_gc_arena_save(mrb);
-    sub = mrb_string_type(mrb, argv[i]);
+    sub = mrb_ensure_string_type(mrb, argv[i]);
     mrb_gc_arena_restore(mrb, ai);
     len_l = RSTRING_LEN(self);
     len_r = RSTRING_LEN(sub);
@@ -220,7 +220,7 @@ mrb_str_end_with(mrb_state *mrb, mrb_value self)
   for (i = 0; i < argc; i++) {
     size_t len_l, len_r;
     int ai = mrb_gc_arena_save(mrb);
-    sub = mrb_string_type(mrb, argv[i]);
+    sub = mrb_ensure_string_type(mrb, argv[i]);
     mrb_gc_arena_restore(mrb, ai);
     len_l = RSTRING_LEN(self);
     len_r = RSTRING_LEN(sub);

src/class.c

@@ -1979,7 +1979,7 @@ mrb_mod_const_get(mrb_state *mrb, mrb_value mod)
   }
 
   /* const get with class path string */
-  path = mrb_string_type(mrb, path);
+  path = mrb_ensure_string_type(mrb, path);
   ptr = RSTRING_PTR(path);
   len = RSTRING_LEN(path);
   off = 0;

src/object.c

@@ -590,7 +590,7 @@ mrb_to_str(mrb_state *mrb, mrb_value val)
 }
 
 MRB_API mrb_value
-mrb_string_type(mrb_state *mrb, mrb_value str)
+mrb_ensure_string_type(mrb_state *mrb, mrb_value str)
 {
   if (!mrb_string_p(str)) {
     mrb_raisef(mrb, E_TYPE_ERROR, "%S cannot be converted to String",