re PR c++/47999 ([C++0x] auto type deduction works incorrectly in a function template)

	PR c++/47999
	* semantics.c (finish_call_expr): Preserve reference semantics
	in templates.

From-SVN: r171053

gcc/cp/ChangeLog

 2011-03-16  Jason Merrill  <jason@redhat.com>
 
+	PR c++/47999
+	* semantics.c (finish_call_expr): Preserve reference semantics
+	in templates.
+
 	* call.c (convert_default_arg): Use LOOKUP_IMPLICIT.
 
 2011-03-16  Jakub Jelinek  <jakub@redhat.com>

gcc/cp/semantics.c

@@ -2150,11 +2150,17 @@ finish_call_expr (tree fn, VEC(tree,gc) **args, bool disallow_virtual,
     /* A call where the function is unknown.  */
     result = cp_build_function_call_vec (fn, args, complain);
 
-  if (processing_template_decl)
+  if (processing_template_decl && result != error_mark_node)
     {
+      if (TREE_CODE (result) == INDIRECT_REF)
+	result = TREE_OPERAND (result, 0);
+      gcc_assert (TREE_CODE (result) == CALL_EXPR
+		  || TREE_CODE (fn) == PSEUDO_DTOR_EXPR
+		  || errorcount);
       result = build_call_vec (TREE_TYPE (result), orig_fn, orig_args);
       KOENIG_LOOKUP_P (result) = koenig_p;
       release_tree_vector (orig_args);
+      result = convert_from_reference (result);
     }
 
   return result;

gcc/testsuite/ChangeLog

+2011-03-16  Jason Merrill  <jason@redhat.com>
+
+	* g++.dg/cpp0x/auto22.C: New.
+
 2011-03-16  Richard Guenther  <rguenther@suse.de>
 
 	* gcc.dg/guality/vla-1.c (main): Use result of f1 to avoid

gcc/testsuite/g++.dg/cpp0x/auto22.C

+// PR c++/47999
+// { dg-options -std=c++0x }
+
+int& identity(int& i)
+{
+  return i;
+}
+
+// In a function template, auto type deduction works incorrectly.
+template <typename = void>
+void f()
+{
+  int i = 0;
+  auto&& x = identity(i); // Type of x should be `int&`, but it is `int&&`.
+}
+
+int main (int argc, char* argv[])
+{
+  f();
+  return 0;
+}