Remove `mrb_funcall` from `mrb_method_search`.

src/class.c

@@ -1333,6 +1333,8 @@ mrb_method_search_vm(mrb_state *mrb, struct RClass **cp, mrb_sym mid)
   return m;                  /* no method */
 }
 
+mrb_value mrb_mod_to_s(mrb_state *mrb, mrb_value klass);
+
 MRB_API mrb_method_t
 mrb_method_search(mrb_state *mrb, struct RClass* c, mrb_sym mid)
 {
@@ -1340,11 +1342,8 @@ mrb_method_search(mrb_state *mrb, struct RClass* c, mrb_sym mid)
 
   m = mrb_method_search_vm(mrb, &c, mid);
   if (MRB_METHOD_UNDEF_P(m)) {
-    mrb_value inspect = mrb_funcall(mrb, mrb_obj_value(c), "inspect", 0);
-    if (mrb_string_p(inspect) && RSTRING_LEN(inspect) > 64) {
-      inspect = mrb_any_to_s(mrb, mrb_obj_value(c));
-    }
-    mrb_name_error(mrb, mid, "undefined method '%n' for class %v", mid, inspect);
+    mrb_value str = mrb_mod_to_s(mrb, mrb_obj_value(c));
+    mrb_name_error(mrb, mid, "undefined method '%n' for class %v", mid, str);
   }
   return m;
 }