error.c: suppress warnings

* error.c (rb_error_frozen_object): use rb_attr_get instead of
  rb_ivar_get to get rid of warnings for string objects created
  when frozen-string-literal-debug is disabled.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52299 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Tue Oct 27 16:41:05 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* error.c (rb_error_frozen_object): use rb_attr_get instead of
+	  rb_ivar_get to get rid of warnings for string objects created
+	  when frozen-string-literal-debug is disabled.
+
 Tue Oct 27 16:18:12 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/logger.rb (Logger::Period#previous_period_end): as weekly

error.c

@@ -2227,8 +2227,12 @@ void
 rb_error_frozen_object(VALUE frozen_obj)
 {
     VALUE path, line;
-    if ((path = rb_iv_get(frozen_obj, "__object_created_path__")) != Qnil &&
-	(line = rb_iv_get(frozen_obj, "__object_created_line__")) != Qnil) {
+    ID created_path, created_line;
+
+    CONST_ID(created_path, "__object_created_path__");
+    CONST_ID(created_line, "__object_created_line__");
+    if (!NIL_P(path = rb_attr_get(frozen_obj, created_path)) &&
+	!NIL_P(line = rb_attr_get(frozen_obj, created_line))) {
 	rb_raise(rb_eRuntimeError, "can't modify frozen %"PRIsVALUE", created at %"PRIsVALUE":%"PRIsVALUE,
 		 CLASS_OF(frozen_obj), path, line);
     }