parse.y: clear lex_strterm

* parse.y (parser_heredoc_restore): clear lex_strterm always to get
  rid of marking recycled node.  this bug is revealed by r41372 with
  GC.stress=true.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41378 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Tue Jun 18 16:43:44 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (parser_heredoc_restore): clear lex_strterm always to get
+	  rid of marking recycled node.  this bug is revealed by r41372 with
+	  GC.stress=true.
+
 Tue Jun 18 12:53:25 2013  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (nlz): Cast the result explicitly.

parse.y

@@ -6345,6 +6345,7 @@ parser_heredoc_restore(struct parser_params *parser, NODE *here)
 {
     VALUE line;
 
+    lex_strterm = 0;
     line = here->nd_orig;
     lex_lastline = line;
     lex_pbeg = RSTRING_PTR(line);
@@ -6419,7 +6420,6 @@ parser_here_document(struct parser_params *parser, NODE *here)
 #endif
       restore:
 	heredoc_restore(lex_strterm);
-	lex_strterm = 0;
 	return 0;
     }
     if (was_bol() && whole_match_p(eos, len, indent)) {