https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109680
--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #4)
> template <typename T, typename U = T&&>
> U __declval (int);
> template <typename T>
> T __declval (long);
> template <typename T>
> auto declval () noexcept -> decltype (__declval <T> (0));
> using To = int () const;
> using From = int (*) ();
> To foo () { return declval <From> (); }
> From bar () { return declval <To> (); }
> static_assert (!__is_convertible (To, From), "");
> static_assert (!__is_convertible (From, To), "");
> should show that both assertions should succeed.
Thanks.
> Dunno if in this case the
> reason why it isn't convertible is simply the fact that functions can't be
> declared to return function/method/array types or some other reason as well.
Yeah, I'm also not sure, so I think this should fix it:
--- a/gcc/cp/method.cc
+++ b/gcc/cp/method.cc
@@ -2245,6 +2245,8 @@ is_convertible_helper (tree from, tree to)
{
if (VOID_TYPE_P (from) && VOID_TYPE_P (to))
return integer_one_node;
+ if (FUNC_OR_METHOD_TYPE_P (from) || FUNC_OR_METHOD_TYPE_P (to))
+ return error_mark_node;
cp_unevaluated u;
tree expr = build_stub_object (from);
deferring_access_check_sentinel acs (dk_no_deferred);
Since
static_assert (!__is_convertible (int[3], int[3]), "");
already passes, arrays are handled correctly I think.
