From patchwork Mon Nov 19 14:04:38 2012
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Subject: [C++] PR 55368
Date: Mon, 19 Nov 2012 04:04:38 -0000
From: Paolo Carlini <paolo.carlini@oracle.com>
X-Patchwork-Id: 200008
Message-Id: <50AA3C76.9060307@oracle.com>
To: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Cc: Jason Merrill <jason@redhat.com>

Hi,

the issue is that we accept a stray comma at the end of a member 
declaration. The reason is very simple: toward the end of the 
cp_parser_member_declaration main loop, we simply consume a comma token, 
without checking that isn't immediately followed by a semi colon. Thus 
the below, which passes testing on x86_64-linux. Alternately something 
like patch *_2?

Thanks,
Paolo.

//////////////////////
/cp
2012-11-19  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/55368
	* parser.c (cp_parser_member_declaration): Emit an error in case
	of stray comma at end of member declaration.

/testsuite
2012-11-19  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/55368
	* g++.dg/parse/struct-5.C: New.

Index: parser.c
===================================================================
--- parser.c	(revision 193618)
+++ parser.c	(working copy)
@@ -19004,6 +19003,7 @@
   cp_token *initializer_token_start = NULL;
   int saved_pedantic;
   bool saved_colon_corrects_to_scope_p = parser->colon_corrects_to_scope_p;
+  bool seen_comma = false;
 
   /* Check for the `__extension__' keyword.  */
   if (cp_parser_extension_opt (parser, &saved_pedantic))
@@ -19407,7 +19407,10 @@
 	  parser->object_scope = NULL_TREE;
 	  /* If it's a `,', then there are more declarators.  */
 	  if (cp_lexer_next_token_is (parser->lexer, CPP_COMMA))
-	    cp_lexer_consume_token (parser->lexer);
+	    {
+	      seen_comma = true;
+	      cp_lexer_consume_token (parser->lexer);
+	    }
 	  /* If the next token isn't a `;', then we have a parse error.  */
 	  else if (cp_lexer_next_token_is_not (parser->lexer,
 					       CPP_SEMICOLON))
@@ -19425,6 +19428,8 @@
 		 and issue nonsensical error messages.  */
 	      assume_semicolon = true;
 	    }
+	  else
+	    seen_comma = false;
 
 	  if (decl)
 	    {
@@ -19446,6 +19451,13 @@
 	}
     }
 
+  if (seen_comma)
+    {
+      cp_token *token = cp_lexer_previous_token (parser->lexer);
+      error_at (token->location,
+		"stray %<,%> at end of member declaration");
+    }
+
   cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
  out:
   parser->colon_corrects_to_scope_p = saved_colon_corrects_to_scope_p;


Index: cp/parser.c
===================================================================
--- cp/parser.c	(revision 193618)
+++ cp/parser.c	(working copy)
@@ -19407,7 +19406,15 @@ cp_parser_member_declaration (cp_parser* parser)
 	  parser->object_scope = NULL_TREE;
 	  /* If it's a `,', then there are more declarators.  */
 	  if (cp_lexer_next_token_is (parser->lexer, CPP_COMMA))
-	    cp_lexer_consume_token (parser->lexer);
+	    {
+	      cp_lexer_consume_token (parser->lexer);
+	      if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
+		{
+		  cp_token *token = cp_lexer_previous_token (parser->lexer);
+		  error_at (token->location,
+			    "stray %<,%> at end of member declaration");
+		}
+	    }
 	  /* If the next token isn't a `;', then we have a parse error.  */
 	  else if (cp_lexer_next_token_is_not (parser->lexer,
 					       CPP_SEMICOLON))
Index: testsuite/g++.dg/parse/struct-5.C
===================================================================
--- testsuite/g++.dg/parse/struct-5.C	(revision 0)
+++ testsuite/g++.dg/parse/struct-5.C	(working copy)
@@ -0,0 +1,3 @@
+// PR c++/55368
+
+struct A { struct B *C,; };  // { dg-error "stray" }