range.c: check if range modifiable

* range.c (range_modify): frozen object cannot be modified.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56693 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

range.c

@@ -80,6 +80,7 @@ rb_range_new(VALUE beg, VALUE end, int exclude_end)
 static void
 range_modify(VALUE range)
 {
+    rb_check_frozen(range);
     /* Ranges are immutable, so that they should be initialized only once. */
     if (RANGE_EXCL(range) != Qnil) {
 	rb_name_err_raise("`initialize' called twice", range, ID2SYM(idInitialize));

test/ruby/test_range.rb

@@ -11,6 +11,12 @@ class TestRange < Test::Unit::TestCase
     assert_equal((0...2), Range.new(0, 2, true))
   end
 
+  def test_frozen_initialize
+    r = Range.allocate
+    r.freeze
+    assert_raise(RuntimeError){r.__send__(:initialize, 1, 2)}
+  end
+
   def test_range_string
     # XXX: Is this really the test of Range?
     assert_equal([], ("a" ... "a").to_a)