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[C++] PR 57543

Message ID 5385064C.9020203@oracle.com
State New
Headers show

Commit Message

Paolo Carlini May 27, 2014, 9:40 p.m. UTC 
Hi,

On 05/27/2014 07:15 PM, Jason Merrill wrote:
> I don't think this is the right place for the fix; why do we have a 
> dummy object at all?  Doesn't maybe_dummy_object return 
> current_class_ref in this situation?
I see, thanks for the dummy object clarification.

Therefore, it seems to me that the real issue is that current_class_ref 
is null when maybe_dummy_object is called in the template case, vs the 
non-template case where cp_parser_late_return_type_opt calls 
inject_this_parameter. Thus the below, which at least passes testing.

The most tricky case is tested with struct Z: in that case 
tsubst_function_type is called , via 3/4 hops, from fn_type_unification, 
thus the former cannot simply use current_class_type, which is null. I 
tried to cope with that by using DECL_CONTEXT (in_decl) but then 
fn_type_unification has to pass the actual TEMPLATE_DECL as in_decl, not 
NULL_TREE. Is that reasonable??

Thanks!
Paolo.

////////////////////
diff mbox

Patch

Index: cp/pt.c
===================================================================
--- cp/pt.c	(revision 210956)
+++ cp/pt.c	(working copy)
@@ -11323,7 +11323,28 @@  tsubst_function_type (tree t,
   gcc_assert (TYPE_CONTEXT (t) == NULL_TREE);
 
   /* Substitute the return type.  */
+  tree save_ccp = current_class_ptr;
+  tree save_ccr = current_class_ref;
+  bool do_inject = (!current_class_ref
+		    && TREE_CODE (t) == METHOD_TYPE
+		    && TREE_CODE (TREE_TYPE (t)) == DECLTYPE_TYPE);
+  if (do_inject)
+    {
+      /* DR 1207: 'this' is in scope in the trailing return type.  */
+      inject_this_parameter (current_class_type
+			     ? current_class_type
+			     : DECL_CONTEXT (in_decl),
+			     type_memfn_quals (t));
+    }
+
   return_type = tsubst (TREE_TYPE (t), args, complain, in_decl);
+
+  if (do_inject)
+    {
+      current_class_ptr = save_ccp;
+      current_class_ref = save_ccr;
+    }
+
   if (return_type == error_mark_node)
     return error_mark_node;
   /* DR 486 clarifies that creation of a function type with an
@@ -15872,7 +15893,7 @@  fn_type_unification (tree fn,
 	 access path at this point.  */
       push_deferring_access_checks (dk_deferred);
       fntype = tsubst (TREE_TYPE (fn), explicit_targs,
-		       complain | tf_partial, NULL_TREE);
+		       complain | tf_partial, fn);
       pop_deferring_access_checks ();
       input_location = loc;
       processing_template_decl -= incomplete;
Index: testsuite/g++.dg/cpp0x/decltype59.C
===================================================================
--- testsuite/g++.dg/cpp0x/decltype59.C	(revision 0)
+++ testsuite/g++.dg/cpp0x/decltype59.C	(working copy)
@@ -0,0 +1,29 @@ 
+// PR c++/57543
+// { dg-do compile { target c++11 } }
+
+template< typename > struct X
+{
+  void foo();
+  auto bar() -> decltype( X::foo() );
+};
+
+template< typename > struct Y
+{
+  void foo();
+  template< typename >
+  auto bar() -> decltype( Y::foo() );
+};
+
+template< typename > struct Z
+{
+  void foo();
+  template< typename T>
+  auto bar() -> decltype( T::foo() );
+};
+
+int main()
+{
+  X<int>().bar();
+  Y<int>().bar<double>();
+  Z<int>().bar<Z<int>>();
+}