Hi,
On 26/02/19 15:28, Jason Merrill wrote:
On 2/25/19 10:27 AM, Paolo Carlini wrote:
Hi,
this error recovery regression has to do with the recent changes
committed by Jason for c++/88368. What happens is that
maybe_instantiate_noexcept fails the hard way, thus, toward the end
of the function, doesn't update TREE_TYPE (fn) and just returns
false. process_subob_fn doesn't notice and proceeds to call
merge_exception_specifiers anyway where of course the gcc_assert
(!DEFERRED_NOEXCEPT_SPEC_P (add)) triggers, because
maybe_instantiate_noexcept has not done its normal job. To improve
error-recovery I think we can simply leave *spec_p alone in such
cases, because we would merge the *spec_p with a
TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn)) where TREE_TYPE (fn) has not
been normally computed. I tried a few other things which prima facie
looked sensible but nothing else worked - eg, returning false from
maybe_instantiate_noexcept and also updating TREE_TYPE (fn) to a
noexcept_false_spec variant causes regressions exactly for the
testcases of c++/88368.
If maybe_instantiate_noexcept returns false, I think we should set
*spec_p to error_mark_node.
Sure, that certainly works, I tested it a couple of days ago and I'm
finishing testing the below now. The only difference is that during
error-recovery 'zl ()' is seen as seriously broken and we don't give the
second, "cannot convert", error message, which we used to give.
Thanks, Paolo.
/////////////////////
Index: cp/method.c
===================================================================
--- cp/method.c (revision 269187)
+++ cp/method.c (working copy)
@@ -1256,9 +1256,13 @@ process_subob_fn (tree fn, tree *spec_p, bool *tri
if (spec_p)
{
- maybe_instantiate_noexcept (fn);
- tree raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn));
- *spec_p = merge_exception_specifiers (*spec_p, raises);
+ if (!maybe_instantiate_noexcept (fn))
+ *spec_p = error_mark_node;
+ else
+ {
+ tree raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn));
+ *spec_p = merge_exception_specifiers (*spec_p, raises);
+ }
}
if (!trivial_fn_p (fn) && !dtor_from_ctor)
Index: testsuite/g++.dg/cpp0x/nsdmi15.C
===================================================================
--- testsuite/g++.dg/cpp0x/nsdmi15.C (nonexistent)
+++ testsuite/g++.dg/cpp0x/nsdmi15.C (working copy)
@@ -0,0 +1,8 @@
+// PR c++/89488
+// { dg-do compile { target c++11 } }
+
+struct zl {
+ struct {
+ int x2 = zl (); // { dg-error "default member" }
+ } fx;
+};
