| Message ID | 20210914084808.GU304296@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | c++: Fix __is_*constructible/assignable for templates [PR102305] | expand |
On 9/14/21 4:48 AM, Jakub Jelinek wrote: > is_xible_helper returns error_mark_node (i.e. false from the traits) > for abstract classes by testing ABSTRACT_CLASS_TYPE_P (to) early. > Unfortunately, as the testcase shows, that doesn't work on class templates > that haven't been instantiated yet, ABSTRACT_CLASS_TYPE_P for them is false > until it is instantiated, which is done when the routine later constructs > a dummy object with that type. > > The following patch fixes this by calling complete_type first, so that > ABSTRACT_CLASS_TYPE_P test will work properly, while keeping the handling > of arrays with unknown bounds, or incomplete types where it is done > currently. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? OK. > 2021-09-14 Jakub Jelinek <jakub@redhat.com> > > PR c++/102305 > * method.c (is_xible_helper): Call complete_type on to. > > * g++.dg/cpp0x/pr102305.C: New test. > > --- gcc/cp/method.c.jj 2021-08-12 09:34:16.465241411 +0200 > +++ gcc/cp/method.c 2021-09-13 12:29:05.398000237 +0200 > @@ -2081,6 +2081,7 @@ constructible_expr (tree to, tree from) > static tree > is_xible_helper (enum tree_code code, tree to, tree from, bool trivial) > { > + to = complete_type (to); > deferring_access_check_sentinel acs (dk_no_deferred); > if (VOID_TYPE_P (to) || ABSTRACT_CLASS_TYPE_P (to) > || (from && FUNC_OR_METHOD_TYPE_P (from) > --- gcc/testsuite/g++.dg/cpp0x/pr102305.C.jj 2021-09-13 12:46:47.580332966 +0200 > +++ gcc/testsuite/g++.dg/cpp0x/pr102305.C 2021-09-13 12:49:00.072503394 +0200 > @@ -0,0 +1,39 @@ > +// PR c++/102305 > +// { dg-do compile { target c++11 } } > + > +namespace std > +{ > + template<typename _Tp, _Tp __v> > + struct integral_constant > + { > + static constexpr _Tp value = __v; > + typedef integral_constant<_Tp, __v> type; > + }; > + > + template<typename _Tp, _Tp __v> > + constexpr _Tp integral_constant<_Tp, __v>::value; > + > + typedef integral_constant<bool, true> true_type; > + typedef integral_constant<bool, false> false_type; > + > + template<bool __v> > + using bool_constant = integral_constant<bool, __v>; > + > + template<typename _Tp, typename... _Args> > + struct is_constructible > + : public bool_constant<__is_constructible(_Tp, _Args...)> > + { > + }; > +} > + > +template<typename> > +struct A { > + virtual ~A() = 0; > +}; > + > +struct B { > + virtual ~B() = 0; > +}; > + > +static_assert(!std::is_constructible<A<int> >::value, ""); > +static_assert(!std::is_constructible<B>::value, ""); > > Jakub >
--- gcc/cp/method.c.jj 2021-08-12 09:34:16.465241411 +0200 +++ gcc/cp/method.c 2021-09-13 12:29:05.398000237 +0200 @@ -2081,6 +2081,7 @@ constructible_expr (tree to, tree from) static tree is_xible_helper (enum tree_code code, tree to, tree from, bool trivial) { + to = complete_type (to); deferring_access_check_sentinel acs (dk_no_deferred); if (VOID_TYPE_P (to) || ABSTRACT_CLASS_TYPE_P (to) || (from && FUNC_OR_METHOD_TYPE_P (from) --- gcc/testsuite/g++.dg/cpp0x/pr102305.C.jj 2021-09-13 12:46:47.580332966 +0200 +++ gcc/testsuite/g++.dg/cpp0x/pr102305.C 2021-09-13 12:49:00.072503394 +0200 @@ -0,0 +1,39 @@ +// PR c++/102305 +// { dg-do compile { target c++11 } } + +namespace std +{ + template<typename _Tp, _Tp __v> + struct integral_constant + { + static constexpr _Tp value = __v; + typedef integral_constant<_Tp, __v> type; + }; + + template<typename _Tp, _Tp __v> + constexpr _Tp integral_constant<_Tp, __v>::value; + + typedef integral_constant<bool, true> true_type; + typedef integral_constant<bool, false> false_type; + + template<bool __v> + using bool_constant = integral_constant<bool, __v>; + + template<typename _Tp, typename... _Args> + struct is_constructible + : public bool_constant<__is_constructible(_Tp, _Args...)> + { + }; +} + +template<typename> +struct A { + virtual ~A() = 0; +}; + +struct B { + virtual ~B() = 0; +}; + +static_assert(!std::is_constructible<A<int> >::value, ""); +static_assert(!std::is_constructible<B>::value, "");