* compile.c (iseq_compile_each): Dynamic string literals (e.g.,

"#{x}") should not be frozen because they don't literally
  represent strings.
  https://twitter.com/shugomaeda/status/651937650027401216
  https://twitter.com/yukihiro_matz/status/651942882312482817
  https://twitter.com/yukihiro_matz/status/651980835181096960

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52087 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,12 @@
+Fri Oct  9 12:52:08 2015  Shugo Maeda  <shugo@ruby-lang.org>
+
+	* compile.c (iseq_compile_each): Dynamic string literals (e.g.,
+	  "#{x}") should not be frozen because they don't literally
+	  represent strings.
+	  https://twitter.com/shugomaeda/status/651937650027401216
+	  https://twitter.com/yukihiro_matz/status/651942882312482817
+	  https://twitter.com/yukihiro_matz/status/651980835181096960
+
 Fri Oct  9 06:52:49 2015  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* benchmark/prepare_require.rb: skip file creation if it already

compile.c

@@ -5059,11 +5059,6 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR *ret, NODE * node, int poped)
 	if (poped) {
 	    ADD_INSN(ret, line, pop);
 	}
-	else {
-	    if (iseq->compile_data->option->frozen_string_literal) {
-		ADD_SEND (ret, line, idFreeze, INT2FIX(0));
-	    }
-	}
 	break;
       }
       case NODE_XSTR:{

test/ruby/test_iseq.rb

@@ -166,12 +166,13 @@ class TestISeq < Test::Unit::TestCase
     $f = 'f'
     line = __LINE__ + 2
     code = <<-'EOS'
-    ['foo', 'foo', "#{$f}foo"]
+    ['foo', 'foo', "#{$f}foo", "#{'foo'}"]
     EOS
-    s1, s2, s3 = RubyVM::InstructionSequence.compile(code, __FILE__, __FILE__, line, {frozen_string_literal: true}).eval
-    assert(s1.frozen?)
-    assert(s2.frozen?)
-    assert(s3.frozen?)
-    assert(s1.object_id == s2.object_id)
+    s1, s2, s3, s4 = RubyVM::InstructionSequence.compile(code, __FILE__, __FILE__, line, {frozen_string_literal: true}).eval
+    assert_equal(true, s1.frozen?)
+    assert_equal(true, s2.frozen?)
+    assert_equal(false, s3.frozen?)
+    assert_equal(true, s4.frozen?)
+    assert_equal(s2.object_id, s2.object_id)
   end
 end