parse.y: should not deent concatenated string

* parse.y (string1): reset heredoc indent fore each string leteral
  so that concatenated string would not be dedented.
  [ruby-core:72857] [Bug #11990]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53541 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Fri Jan 15 16:12:10 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (string1): reset heredoc indent fore each string leteral
+	  so that concatenated string would not be dedented.
+	  [ruby-core:72857] [Bug #11990]
+
 Fri Jan 15 09:25:07 2016  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* common.mk: test-sample was changed to test-basic.

parse.y

@@ -3912,7 +3912,6 @@ strings		: string
 			else {
 			    node = evstr2dstr(node);
 			}
-			heredoc_indent = 0;
 			$$ = node;
 		    /*%
 			$$ = $1;
@@ -3935,6 +3934,7 @@ string		: tCHAR
 string1		: tSTRING_BEG string_contents tSTRING_END
 		    {
 			heredoc_dedent($2);
+			heredoc_indent = 0;
 		    /*%%%*/
 			$$ = $2;
 		    /*%

test/ruby/test_syntax.rb

@@ -580,6 +580,15 @@ e"
     assert_dedented_heredoc(expect, result)
   end
 
+  def test_dedented_heredoc_with_concatenation
+    bug11990 = '[ruby-core:72857] [Bug #11990] concatenated string should not be dedented'
+    %w[eos "eos" 'eos'].each do |eos|
+      assert_equal("x\n  y",
+                   eval("<<~#{eos} '  y'\n  x\neos\n"),
+                   "#{bug11990} with #{eos}")
+    end
+  end
+
   def test_lineno_after_heredoc
     bug7559 = '[ruby-dev:46737]'
     expected, _, actual = __LINE__, <<eom, __LINE__