diff mbox

[C++] PR 50732

Message ID 4E98B07E.6060409@oracle.com
State New
Headers show

Commit Message

Paolo Carlini Oct. 14, 2011, 9:58 p.m. UTC 
On 10/14/2011 09:08 PM, Jason Merrill wrote:
> How about using complete_type_or_else?
The CPTK_IS_BASE_OF case becomes much simpler indeed, thanks. For the 
unary traits, though, I don't see an advantage in using it, because in 
some cases in check_trait_type we don't want to error out even when 
complete_type_or_else would. Unless we can check whether we are dealing 
with an array of unknown bound *before* completing the type? That is:

   if (TREE_CODE (type) == ARRAY_TYPE && !TYPE_DOMAIN (type)
&& COMPLETE_TYPE_P (TREE_TYPE (type)))

is the outcome always the same before and after trying to complete (type)?

Thanks,
Paolo.

//////////////////////

Comments

Jason Merrill Oct. 14, 2011, 10:20 p.m. UTC | #1 
On 10/14/2011 05:58 PM, Paolo Carlini wrote:
> On 10/14/2011 09:08 PM, Jason Merrill wrote:
>> How about using complete_type_or_else?
> The CPTK_IS_BASE_OF case becomes much simpler indeed, thanks. For the
> unary traits, though, I don't see an advantage in using it, because in
> some cases in check_trait_type we don't want to error out even when
> complete_type_or_else would. Unless we can check whether we are dealing
> with an array of unknown bound *before* completing the type? That is:
>
> if (TREE_CODE (type) == ARRAY_TYPE && !TYPE_DOMAIN (type)
> && COMPLETE_TYPE_P (TREE_TYPE (type)))
>
> is the outcome always the same before and after trying to complete (type)?

That should work.

Jason
diff mbox

Patch

Index: testsuite/g++.dg/ext/is_base_of_diagnostic.C
===================================================================
--- testsuite/g++.dg/ext/is_base_of_diagnostic.C	(revision 180007)
+++ testsuite/g++.dg/ext/is_base_of_diagnostic.C	(working copy)
@@ -1,7 +1,7 @@ 
 class A
 { };
 
-class B;
+class B; // { dg-error "forward declaration" }
 
 union C
 { };
Index: testsuite/g++.dg/ext/is_base_of_incomplete.C
===================================================================
--- testsuite/g++.dg/ext/is_base_of_incomplete.C	(revision 0)
+++ testsuite/g++.dg/ext/is_base_of_incomplete.C	(revision 0)
@@ -0,0 +1,7 @@ 
+template <typename T>
+struct non_instantiable
+{
+  typedef typename T::THIS_TYPE_CANNOT_BE_INSTANTIATED type;
+};
+
+int check[__is_base_of(non_instantiable<int>, void) ? -1 : 1];
Index: cp/semantics.c
===================================================================
--- cp/semantics.c	(revision 180007)
+++ cp/semantics.c	(working copy)
@@ -5276,10 +5276,6 @@  finish_trait_expr (cp_trait_kind kind, tree type1,
       return trait_expr;
     }
 
-  complete_type (type1);
-  if (type2)
-    complete_type (type2);
-
   switch (kind)
     {
     case CPTK_HAS_NOTHROW_ASSIGN:
@@ -5297,9 +5293,10 @@  finish_trait_expr (cp_trait_kind kind, tree type1,
     case CPTK_IS_POLYMORPHIC:
     case CPTK_IS_STD_LAYOUT:
     case CPTK_IS_TRIVIAL:
+      complete_type (type1);
       if (!check_trait_type (type1))
 	{
-	  error ("incomplete type %qT not allowed", type1);
+	  error ("invalid use of incomplete type %qT", type1);
 	  return error_mark_node;
 	}
       break;
@@ -5307,11 +5304,9 @@  finish_trait_expr (cp_trait_kind kind, tree type1,
     case CPTK_IS_BASE_OF:
       if (NON_UNION_CLASS_TYPE_P (type1) && NON_UNION_CLASS_TYPE_P (type2)
 	  && !same_type_ignoring_top_level_qualifiers_p (type1, type2)
-	  && !COMPLETE_TYPE_P (type2))
-	{
-	  error ("incomplete type %qT not allowed", type2);
-	  return error_mark_node;
-	}
+	  && !complete_type_or_else (type2, NULL_TREE))
+	/* We already issued an error.  */
+	return error_mark_node;
       break;
 
     case CPTK_IS_CLASS: