commit 716725435749074db5f5e7ef70b8950331e8315d
Author: Jason Merrill <jason@redhat.com>
Date: Tue May 8 17:39:10 2018 -0400
PR c++/85706 - class deduction under decltype
* pt.c (for_each_template_parm_r): Handle DECLTYPE_TYPE. Clear
*walk_subtrees whether or not we walked into the operand.
(type_uses_auto): Only look at deduced contexts.
@@ -9829,6 +9829,7 @@ for_each_template_parm_r (tree *tp, int *walk_subtrees, void *d)
break;
case TYPEOF_TYPE:
+ case DECLTYPE_TYPE:
case UNDERLYING_TYPE:
if (pfd->include_nondeduced_p
&& for_each_template_parm (TYPE_VALUES_RAW (t), fn, data,
@@ -9836,6 +9837,7 @@ for_each_template_parm_r (tree *tp, int *walk_subtrees, void *d)
pfd->include_nondeduced_p,
pfd->any_fn))
return error_mark_node;
+ *walk_subtrees = false;
break;
case FUNCTION_DECL:
@@ -26862,7 +26864,7 @@ type_uses_auto (tree type)
them. */
if (uses_template_parms (type))
return for_each_template_parm (type, is_auto_r, /*data*/NULL,
- /*visited*/NULL, /*nondeduced*/true);
+ /*visited*/NULL, /*nondeduced*/false);
else
return NULL_TREE;
}
new file mode 100644
@@ -0,0 +1,9 @@
+// PR c++/85706
+// { dg-additional-options "-std=c++17 -fconcepts" }
+
+template<class T> struct S {
+ S(T);
+};
+
+template<class = void>
+auto f() -> decltype(S(42)); // error