parse.y: keep literal encoding

* parse.y (literal_concat_gen, evstr2dstr_gen): keep literal
  encoding beginning with an interpolation same as the source file
  encoding.  [ruby-core:70703] [Bug #11519]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51820 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Thu Sep 10 22:48:49 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (literal_concat_gen, evstr2dstr_gen): keep literal
+	  encoding beginning with an interpolation same as the source file
+	  encoding.  [ruby-core:70703] [Bug #11519]
+
 Thu Sep 10 22:15:51 2015  Joe Rafaniello  <jrafanie@redhat.com>
 
 	* process.c (rb_f_spawn): Be more specific regarding "other

parse.y

@@ -8725,7 +8725,7 @@ literal_concat_gen(struct parser_params *parser, NODE *head, NODE *tail)
 
     htype = nd_type(head);
     if (htype == NODE_EVSTR) {
-	NODE *node = NEW_DSTR(Qnil);
+	NODE *node = NEW_DSTR(STR_NEW0());
 	head = list_append(node, head);
 	htype = NODE_DSTR;
     }
@@ -8798,7 +8798,7 @@ static NODE *
 evstr2dstr_gen(struct parser_params *parser, NODE *node)
 {
     if (nd_type(node) == NODE_EVSTR) {
-	node = list_append(NEW_DSTR(Qnil), node);
+	node = list_append(NEW_DSTR(STR_NEW0()), node);
     }
     return node;
 }

test/ruby/test_literal.rb

@@ -102,6 +102,15 @@ class TestRubyLiteral < Test::Unit::TestCase
     assert_equal('FooBar', b, 'r3842')
   end
 
+  def test_dstring_encoding
+    bug11519 = '[ruby-core:70703] [Bug #11519]'
+    ['"foo#{}"', '"#{}foo"', '"#{}"'].each do |code|
+      a = eval("#-*- coding: utf-8 -*-\n#{code}")
+      assert_equal(Encoding::UTF_8, a.encoding,
+                   proc{"#{bug11519}: #{code}.encoding"})
+    end
+  end
+
   def test_dsymbol
     assert_equal :a3c, :"a#{1+2}c"
   end