N3994 Ranged-based for-loops: The Next Generation

	N3994 Ranged-based for-loops: The Next Generation
	* parser.c (cp_lexer_nth_token_is): New.
	(cp_parser_for_init_statement): Allow "for (id : init)".

From-SVN: r212043

gcc/cp/ChangeLog

+2014-06-26  Jason Merrill  <jason@redhat.com>
+
+	N3994 Ranged-based for-loops: The Next Generation
+	* parser.c (cp_lexer_nth_token_is): New.
+	(cp_parser_for_init_statement): Allow "for (id : init)".
+
 2014-06-26  Adam Butcher  <adam@jessamine.co.uk>
 
 	PR c++/61537

gcc/cp/parser.c

@@ -892,6 +892,12 @@ cp_lexer_next_token_is_keyword (cp_lexer* lexer, enum rid keyword)
 }
 
 static inline bool
+cp_lexer_nth_token_is (cp_lexer* lexer, size_t n, enum cpp_ttype type)
+{
+  return cp_lexer_peek_nth_token (lexer, n)->type == type;
+}
+
+static inline bool
 cp_lexer_nth_token_is_keyword (cp_lexer* lexer, size_t n, enum rid keyword)
 {
   return cp_lexer_peek_nth_token (lexer, n)->keyword == keyword;
@@ -10607,6 +10613,23 @@ cp_parser_for_init_statement (cp_parser* parser, tree *decl)
       bool is_range_for = false;
       bool saved_colon_corrects_to_scope_p = parser->colon_corrects_to_scope_p;
 
+      if (cp_lexer_next_token_is (parser->lexer, CPP_NAME)
+	  && cp_lexer_nth_token_is (parser->lexer, 2, CPP_COLON))
+	{
+	  /* N3994 -- for (id : init) ... */
+	  if (cxx_dialect < cxx1z)
+	    pedwarn (input_location, 0, "range-based for loop without a "
+		     "type-specifier only available with "
+		     "-std=c++1z or -std=gnu++1z");
+	  tree name = cp_parser_identifier (parser);
+	  tree type = cp_build_reference_type (make_auto (), /*rval*/true);
+	  *decl = build_decl (input_location, VAR_DECL, name, type);
+	  pushdecl (*decl);
+	  cp_lexer_consume_token (parser->lexer);
+	  return true;
+	}
+
+      /* A colon is used in range-based for.  */
       parser->colon_corrects_to_scope_p = false;
 
       /* We're going to speculatively look for a declaration, falling back

gcc/testsuite/g++.dg/cpp1z/range-for1.C

+// { dg-options "-std=c++1z -pedantic-errors" }
+
+extern "C" int printf (const char *, ...);
+#include <initializer_list>
+
+int main()
+{
+  for (i : {1,2})
+    {
+      printf ("%d ", i);
+    }
+}