* [PATCH] c++: Implement CWG2635 - Constrained structured bindings
@ 2022-11-12 11:23 Jakub Jelinek
2022-11-13 11:50 ` [PATCH] c++, v2: " Jakub Jelinek
0 siblings, 1 reply; 5+ messages in thread
From: Jakub Jelinek @ 2022-11-12 11:23 UTC (permalink / raw)
To: Jason Merrill; +Cc: gcc-patches
Hi!
The following patch implements CWG2635.
So far tested on
GXX_TESTSUITE_STDS=98,11,14,17,20,2b make check-g++ RUNTESTFLAGS="dg.exp=decomp*"
ok for trunk if it passes full bootstrap/regtest and it is voted in?
2022-11-12 Jakub Jelinek <jakub@redhat.com>
* decl.cc (grokdeclarator): Implement
CWG2635 - Constrained structured bindings. Diagnose constrained
auto type.
* g++.dg/cpp2a/decomp5.C: New test.
--- gcc/cp/decl.cc.jj 2022-11-11 17:14:33.103869977 +0100
+++ gcc/cp/decl.cc 2022-11-12 12:13:52.217239729 +0100
@@ -12660,7 +12660,8 @@ grokdeclarator (const cp_declarator *dec
gcc_unreachable ();
}
if (TREE_CODE (type) != TEMPLATE_TYPE_PARM
- || TYPE_IDENTIFIER (type) != auto_identifier)
+ || TYPE_IDENTIFIER (type) != auto_identifier
+ || PLACEHOLDER_TYPE_CONSTRAINTS_INFO (type))
{
if (type != error_mark_node)
{
--- gcc/testsuite/g++.dg/cpp2a/decomp5.C.jj 2022-11-12 12:17:21.024392082 +0100
+++ gcc/testsuite/g++.dg/cpp2a/decomp5.C 2022-11-12 12:20:00.700214521 +0100
@@ -0,0 +1,20 @@
+// CWG2635 - Constrained structured bindings
+// { dg-do compile { target c++20 } }
+
+namespace std {
+ template<typename T> struct tuple_size;
+ template<int, typename> struct tuple_element;
+}
+
+struct A {
+ int i;
+ A(int x) : i(x) {}
+ template <int I> int& get() { return i; }
+};
+
+template<> struct std::tuple_size<A> { static const int value = 2; };
+template<int I> struct std::tuple_element<I,A> { using type = int; };
+
+template<class T> concept C = true;
+C auto [x, y] = A{1}; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C<<placeholder>, >\\\]'" }
+ // { dg-message "type must be cv-qualified 'auto' or reference to cv-qualified 'auto'" "" { target *-*-* } .-1 }
Jakub
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH] c++, v2: Implement CWG2635 - Constrained structured bindings 2022-11-12 11:23 [PATCH] c++: Implement CWG2635 - Constrained structured bindings Jakub Jelinek @ 2022-11-13 11:50 ` Jakub Jelinek 2022-11-15 23:22 ` Jason Merrill 0 siblings, 1 reply; 5+ messages in thread From: Jakub Jelinek @ 2022-11-13 11:50 UTC (permalink / raw) To: Jason Merrill; +Cc: gcc-patches On Sat, Nov 12, 2022 at 12:23:56PM +0100, Jakub Jelinek wrote: > The following patch implements CWG2635. > > So far tested on > GXX_TESTSUITE_STDS=98,11,14,17,20,2b make check-g++ RUNTESTFLAGS="dg.exp=decomp*" > ok for trunk if it passes full bootstrap/regtest and it is voted in? Here is another version of the patch that passed bootstrap/regtest, the only change are tweaks to 2 further testcases. 2022-11-13 Jakub Jelinek <jakub@redhat.com> * decl.cc (grokdeclarator): Implement CWG2635 - Constrained structured bindings. Diagnose constrained auto type. * g++.dg/cpp2a/decomp5.C: New test. * g++.dg/cpp2a/concepts-placeholder7.C: Adjust expected diagnostics. * g++.dg/cpp2a/concepts-placeholder8.C: Likewise. --- gcc/cp/decl.cc.jj 2022-11-11 17:14:33.103869977 +0100 +++ gcc/cp/decl.cc 2022-11-12 12:13:52.217239729 +0100 @@ -12660,7 +12660,8 @@ grokdeclarator (const cp_declarator *dec gcc_unreachable (); } if (TREE_CODE (type) != TEMPLATE_TYPE_PARM - || TYPE_IDENTIFIER (type) != auto_identifier) + || TYPE_IDENTIFIER (type) != auto_identifier + || PLACEHOLDER_TYPE_CONSTRAINTS_INFO (type)) { if (type != error_mark_node) { --- gcc/testsuite/g++.dg/cpp2a/decomp5.C.jj 2022-11-12 12:17:21.024392082 +0100 +++ gcc/testsuite/g++.dg/cpp2a/decomp5.C 2022-11-12 12:20:00.700214521 +0100 @@ -0,0 +1,20 @@ +// CWG2635 - Constrained structured bindings +// { dg-do compile { target c++20 } } + +namespace std { + template<typename T> struct tuple_size; + template<int, typename> struct tuple_element; +} + +struct A { + int i; + A(int x) : i(x) {} + template <int I> int& get() { return i; } +}; + +template<> struct std::tuple_size<A> { static const int value = 2; }; +template<int I> struct std::tuple_element<I,A> { using type = int; }; + +template<class T> concept C = true; +C auto [x, y] = A{1}; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C<<placeholder>, >\\\]'" } + // { dg-message "type must be cv-qualified 'auto' or reference to cv-qualified 'auto'" "" { target *-*-* } .-1 } --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder7.C.jj 2021-04-06 23:49:08.288882716 +0200 +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder7.C 2022-11-13 12:17:38.570047510 +0100 @@ -7,16 +7,16 @@ template <class> void f() { int x[] = {1,2}; int y[] = {3}; - C1 auto [a,b] = x; - C1 auto [c] = y; // { dg-error "constraints" } + C1 auto [a,b] = x; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } + C1 auto [c] = y; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } } template <class T> void g() { T x[] = {1,2}; T y[] = {3}; - C1 auto [a,b] = x; - C1 auto [c] = y; // { dg-error "constraints" } + C1 auto [a,b] = x; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } + C1 auto [c] = y; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } } template void g<int>(); @@ -27,6 +27,6 @@ struct S { int a, b; } s; template <class T> void h() { - const C2<T> auto& [a, b] = s; + const C2<T> auto& [a, b] = s; // { dg-error "structured binding declaration cannot have type 'const auto \\\[requires ::C2<<placeholder>, >\\\]'" } } template void h<int>(); --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder8.C.jj 2021-04-06 23:49:08.288882716 +0200 +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder8.C 2022-11-13 12:19:17.034684881 +0100 @@ -5,6 +5,6 @@ template <class T> concept is_const = __ void f() { int x[] = {1,2}; const int y[] = {3}; - const is_const auto [a,b] = x; // { dg-error "constraints" } - const is_const auto [c] = y; + const is_const auto [a,b] = x; // { dg-error "structured binding declaration cannot have type 'const auto \\\[requires ::is_const<<placeholder>, >\\\]'" } + const is_const auto [c] = y; // { dg-error "structured binding declaration cannot have type 'const auto \\\[requires ::is_const<<placeholder>, >\\\]'" } } Jakub ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] c++, v2: Implement CWG2635 - Constrained structured bindings 2022-11-13 11:50 ` [PATCH] c++, v2: " Jakub Jelinek @ 2022-11-15 23:22 ` Jason Merrill 2022-11-16 10:17 ` [PATCH] c++, v3: " Jakub Jelinek 0 siblings, 1 reply; 5+ messages in thread From: Jason Merrill @ 2022-11-15 23:22 UTC (permalink / raw) To: Jakub Jelinek; +Cc: gcc-patches On 11/13/22 01:50, Jakub Jelinek wrote: > On Sat, Nov 12, 2022 at 12:23:56PM +0100, Jakub Jelinek wrote: >> The following patch implements CWG2635. >> >> So far tested on >> GXX_TESTSUITE_STDS=98,11,14,17,20,2b make check-g++ RUNTESTFLAGS="dg.exp=decomp*" >> ok for trunk if it passes full bootstrap/regtest and it is voted in? > > Here is another version of the patch that passed bootstrap/regtest, the only > change are tweaks to 2 further testcases. > > 2022-11-13 Jakub Jelinek <jakub@redhat.com> > > * decl.cc (grokdeclarator): Implement > CWG2635 - Constrained structured bindings. Diagnose constrained > auto type. Let's make the constrained auto case a pedwarn instead of an error. > * g++.dg/cpp2a/decomp5.C: New test. > * g++.dg/cpp2a/concepts-placeholder7.C: Adjust expected diagnostics. > * g++.dg/cpp2a/concepts-placeholder8.C: Likewise. > > --- gcc/cp/decl.cc.jj 2022-11-11 17:14:33.103869977 +0100 > +++ gcc/cp/decl.cc 2022-11-12 12:13:52.217239729 +0100 > @@ -12660,7 +12660,8 @@ grokdeclarator (const cp_declarator *dec > gcc_unreachable (); > } > if (TREE_CODE (type) != TEMPLATE_TYPE_PARM > - || TYPE_IDENTIFIER (type) != auto_identifier) > + || TYPE_IDENTIFIER (type) != auto_identifier > + || PLACEHOLDER_TYPE_CONSTRAINTS_INFO (type)) > { > if (type != error_mark_node) > { > --- gcc/testsuite/g++.dg/cpp2a/decomp5.C.jj 2022-11-12 12:17:21.024392082 +0100 > +++ gcc/testsuite/g++.dg/cpp2a/decomp5.C 2022-11-12 12:20:00.700214521 +0100 > @@ -0,0 +1,20 @@ > +// CWG2635 - Constrained structured bindings > +// { dg-do compile { target c++20 } } > + > +namespace std { > + template<typename T> struct tuple_size; > + template<int, typename> struct tuple_element; > +} > + > +struct A { > + int i; > + A(int x) : i(x) {} > + template <int I> int& get() { return i; } > +}; > + > +template<> struct std::tuple_size<A> { static const int value = 2; }; > +template<int I> struct std::tuple_element<I,A> { using type = int; }; > + > +template<class T> concept C = true; > +C auto [x, y] = A{1}; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C<<placeholder>, >\\\]'" } > + // { dg-message "type must be cv-qualified 'auto' or reference to cv-qualified 'auto'" "" { target *-*-* } .-1 } > --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder7.C.jj 2021-04-06 23:49:08.288882716 +0200 > +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder7.C 2022-11-13 12:17:38.570047510 +0100 > @@ -7,16 +7,16 @@ template <class> > void f() { > int x[] = {1,2}; > int y[] = {3}; > - C1 auto [a,b] = x; > - C1 auto [c] = y; // { dg-error "constraints" } > + C1 auto [a,b] = x; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } > + C1 auto [c] = y; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } > } > > template <class T> > void g() { > T x[] = {1,2}; > T y[] = {3}; > - C1 auto [a,b] = x; > - C1 auto [c] = y; // { dg-error "constraints" } > + C1 auto [a,b] = x; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } > + C1 auto [c] = y; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } > } > template void g<int>(); > > @@ -27,6 +27,6 @@ struct S { int a, b; } s; > > template <class T> > void h() { > - const C2<T> auto& [a, b] = s; > + const C2<T> auto& [a, b] = s; // { dg-error "structured binding declaration cannot have type 'const auto \\\[requires ::C2<<placeholder>, >\\\]'" } > } > template void h<int>(); > --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder8.C.jj 2021-04-06 23:49:08.288882716 +0200 > +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder8.C 2022-11-13 12:19:17.034684881 +0100 > @@ -5,6 +5,6 @@ template <class T> concept is_const = __ > void f() { > int x[] = {1,2}; > const int y[] = {3}; > - const is_const auto [a,b] = x; // { dg-error "constraints" } > - const is_const auto [c] = y; > + const is_const auto [a,b] = x; // { dg-error "structured binding declaration cannot have type 'const auto \\\[requires ::is_const<<placeholder>, >\\\]'" } > + const is_const auto [c] = y; // { dg-error "structured binding declaration cannot have type 'const auto \\\[requires ::is_const<<placeholder>, >\\\]'" } > } > > > Jakub > ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] c++, v3: Implement CWG2635 - Constrained structured bindings 2022-11-15 23:22 ` Jason Merrill @ 2022-11-16 10:17 ` Jakub Jelinek 2022-11-16 13:12 ` Jason Merrill 0 siblings, 1 reply; 5+ messages in thread From: Jakub Jelinek @ 2022-11-16 10:17 UTC (permalink / raw) To: Jason Merrill; +Cc: gcc-patches On Tue, Nov 15, 2022 at 06:22:36PM -0500, Jason Merrill wrote: > > Here is another version of the patch that passed bootstrap/regtest, the only > > change are tweaks to 2 further testcases. > > > > 2022-11-13 Jakub Jelinek <jakub@redhat.com> > > > > * decl.cc (grokdeclarator): Implement > > CWG2635 - Constrained structured bindings. Diagnose constrained > > auto type. > > Let's make the constrained auto case a pedwarn instead of an error. So like this (i.e. just pedwarn but don't change the type and keep doing what we were before)? 2022-11-16 Jakub Jelinek <jakub@redhat.com> * decl.cc (grokdeclarator): Implement CWG2635 - Constrained structured bindings. Emit a pedwarn on constrained auto type. Add auto_diagnostic_group for error_at and inform for non-auto type on structured bindings declaration. * g++.dg/cpp2a/decomp5.C: New test. * g++.dg/cpp2a/decomp6.C: New test. * g++.dg/cpp2a/decomp7.C: New test. * g++.dg/cpp2a/concepts-placeholder7.C: Adjust expected diagnostics. * g++.dg/cpp2a/concepts-placeholder8.C: Likewise. * g++.dg/cpp2a/concepts-placeholder9.C: New test. * g++.dg/cpp2a/concepts-placeholder10.C: New test. --- gcc/cp/decl.cc.jj 2022-11-16 07:29:11.603716748 +0100 +++ gcc/cp/decl.cc 2022-11-16 11:07:05.169822071 +0100 @@ -12664,6 +12664,7 @@ grokdeclarator (const cp_declarator *dec { if (type != error_mark_node) { + auto_diagnostic_group d; error_at (loc, "structured binding declaration cannot have " "type %qT", type); inform (loc, @@ -12673,6 +12674,10 @@ grokdeclarator (const cp_declarator *dec type = build_qualified_type (make_auto (), type_quals); declspecs->type = type; } + else if (PLACEHOLDER_TYPE_CONSTRAINTS_INFO (type)) + pedwarn (loc, OPT_Wpedantic, + "structured binding declaration cannot have constrained " + "%<auto%> type %qT", type); inlinep = 0; typedef_p = 0; constexpr_p = 0; --- gcc/testsuite/g++.dg/cpp2a/decomp5.C.jj 2022-11-16 10:39:20.469335601 +0100 +++ gcc/testsuite/g++.dg/cpp2a/decomp5.C 2022-11-16 10:46:02.272896156 +0100 @@ -0,0 +1,19 @@ +// CWG2635 - Constrained structured bindings +// { dg-do compile { target c++20 } } + +namespace std { + template<typename T> struct tuple_size; + template<int, typename> struct tuple_element; +} + +struct A { + int i; + A(int x) : i(x) {} + template <int I> int& get() { return i; } +}; + +template<> struct std::tuple_size<A> { static const int value = 2; }; +template<int I> struct std::tuple_element<I,A> { using type = int; }; + +template<class T> concept C = true; +C auto [x, y] = A{1}; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C<<placeholder>, >\\\]'" } --- gcc/testsuite/g++.dg/cpp2a/decomp6.C.jj 2022-11-16 10:46:44.868319518 +0100 +++ gcc/testsuite/g++.dg/cpp2a/decomp6.C 2022-11-16 10:47:07.485013348 +0100 @@ -0,0 +1,20 @@ +// CWG2635 - Constrained structured bindings +// { dg-do compile { target c++20 } } +// { dg-options "-pedantic" } + +namespace std { + template<typename T> struct tuple_size; + template<int, typename> struct tuple_element; +} + +struct A { + int i; + A(int x) : i(x) {} + template <int I> int& get() { return i; } +}; + +template<> struct std::tuple_size<A> { static const int value = 2; }; +template<int I> struct std::tuple_element<I,A> { using type = int; }; + +template<class T> concept C = true; +C auto [x, y] = A{1}; // { dg-warning "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C<<placeholder>, >\\\]'" } --- gcc/testsuite/g++.dg/cpp2a/decomp7.C.jj 2022-11-16 10:47:14.578917309 +0100 +++ gcc/testsuite/g++.dg/cpp2a/decomp7.C 2022-11-16 10:47:32.061680633 +0100 @@ -0,0 +1,20 @@ +// CWG2635 - Constrained structured bindings +// { dg-do compile { target c++20 } } +// { dg-options "-Wno-pedantic" } + +namespace std { + template<typename T> struct tuple_size; + template<int, typename> struct tuple_element; +} + +struct A { + int i; + A(int x) : i(x) {} + template <int I> int& get() { return i; } +}; + +template<> struct std::tuple_size<A> { static const int value = 2; }; +template<int I> struct std::tuple_element<I,A> { using type = int; }; + +template<class T> concept C = true; +C auto [x, y] = A{1}; // { dg-bogus "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C<<placeholder>, >\\\]'" } --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder7.C.jj 2022-11-13 17:53:46.037681901 +0100 +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder7.C 2022-11-16 11:09:56.092513219 +0100 @@ -7,16 +7,18 @@ template <class> void f() { int x[] = {1,2}; int y[] = {3}; - C1 auto [a,b] = x; - C1 auto [c] = y; // { dg-error "constraints" } + C1 auto [a,b] = x; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } + C1 auto [c] = y; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } + // { dg-error "constraints" "" { target *-*-* } .-1 } } template <class T> void g() { T x[] = {1,2}; T y[] = {3}; - C1 auto [a,b] = x; - C1 auto [c] = y; // { dg-error "constraints" } + C1 auto [a,b] = x; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } + C1 auto [c] = y; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } + // { dg-error "constraints" "" { target *-*-* } .-1 } } template void g<int>(); @@ -27,6 +29,6 @@ struct S { int a, b; } s; template <class T> void h() { - const C2<T> auto& [a, b] = s; + const C2<T> auto& [a, b] = s; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'const auto \\\[requires ::C2<<placeholder>, >\\\]'" } } template void h<int>(); --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder8.C.jj 2022-11-13 17:53:46.037681901 +0100 +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder8.C 2022-11-16 11:10:25.432116956 +0100 @@ -5,6 +5,7 @@ template <class T> concept is_const = __ void f() { int x[] = {1,2}; const int y[] = {3}; - const is_const auto [a,b] = x; // { dg-error "constraints" } - const is_const auto [c] = y; + const is_const auto [a,b] = x; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'const auto \\\[requires ::is_const<<placeholder>, >\\\]'" } + // { dg-error "constraints" "" { target *-*-* } .-1 } + const is_const auto [c] = y; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'const auto \\\[requires ::is_const<<placeholder>, >\\\]'" } } --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder9.C.jj 2022-11-16 10:49:54.610750873 +0100 +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder9.C 2022-11-16 11:12:09.234715037 +0100 @@ -0,0 +1,33 @@ +// PR c++/99899 +// { dg-do compile { target c++20 } } +// { dg-options "-Wno-pedantic" } + +template <class T> concept C1 = sizeof(T) > sizeof(int[1]); + +template <class> +void f() { + int x[] = {1,2}; + int y[] = {3}; + C1 auto [a,b] = x; + C1 auto [c] = y; // { dg-error "constraints" } +} + +template <class T> +void g() { + T x[] = {1,2}; + T y[] = {3}; + C1 auto [a,b] = x; + C1 auto [c] = y; // { dg-error "constraints" } +} +template void g<int>(); + + +template <class... Ts> concept C2 = sizeof...(Ts) > 1; + +struct S { int a, b; } s; + +template <class T> +void h() { + const C2<T> auto& [a, b] = s; +} +template void h<int>(); --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder10.C.jj 2022-11-16 10:49:54.610750873 +0100 +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder10.C 2022-11-16 10:50:16.757451058 +0100 @@ -0,0 +1,11 @@ +// { dg-do compile { target c++20 } } +// { dg-options "-Wno-pedantic" } + +template <class T> concept is_const = __is_same(T, const T); + +void f() { + int x[] = {1,2}; + const int y[] = {3}; + const is_const auto [a,b] = x; // { dg-error "constraints" } + const is_const auto [c] = y; +} Jakub ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] c++, v3: Implement CWG2635 - Constrained structured bindings 2022-11-16 10:17 ` [PATCH] c++, v3: " Jakub Jelinek @ 2022-11-16 13:12 ` Jason Merrill 0 siblings, 0 replies; 5+ messages in thread From: Jason Merrill @ 2022-11-16 13:12 UTC (permalink / raw) To: Jakub Jelinek; +Cc: gcc-patches On 11/16/22 05:17, Jakub Jelinek wrote: > On Tue, Nov 15, 2022 at 06:22:36PM -0500, Jason Merrill wrote: >>> Here is another version of the patch that passed bootstrap/regtest, the only >>> change are tweaks to 2 further testcases. >>> >>> 2022-11-13 Jakub Jelinek <jakub@redhat.com> >>> >>> * decl.cc (grokdeclarator): Implement >>> CWG2635 - Constrained structured bindings. Diagnose constrained >>> auto type. >> >> Let's make the constrained auto case a pedwarn instead of an error. > > So like this (i.e. just pedwarn but don't change the type and keep doing > what we were before)? OK. > 2022-11-16 Jakub Jelinek <jakub@redhat.com> > > * decl.cc (grokdeclarator): Implement > CWG2635 - Constrained structured bindings. Emit a pedwarn on > constrained auto type. Add auto_diagnostic_group for error_at > and inform for non-auto type on structured bindings declaration. > > * g++.dg/cpp2a/decomp5.C: New test. > * g++.dg/cpp2a/decomp6.C: New test. > * g++.dg/cpp2a/decomp7.C: New test. > * g++.dg/cpp2a/concepts-placeholder7.C: Adjust expected diagnostics. > * g++.dg/cpp2a/concepts-placeholder8.C: Likewise. > * g++.dg/cpp2a/concepts-placeholder9.C: New test. > * g++.dg/cpp2a/concepts-placeholder10.C: New test. > > --- gcc/cp/decl.cc.jj 2022-11-16 07:29:11.603716748 +0100 > +++ gcc/cp/decl.cc 2022-11-16 11:07:05.169822071 +0100 > @@ -12664,6 +12664,7 @@ grokdeclarator (const cp_declarator *dec > { > if (type != error_mark_node) > { > + auto_diagnostic_group d; > error_at (loc, "structured binding declaration cannot have " > "type %qT", type); > inform (loc, > @@ -12673,6 +12674,10 @@ grokdeclarator (const cp_declarator *dec > type = build_qualified_type (make_auto (), type_quals); > declspecs->type = type; > } > + else if (PLACEHOLDER_TYPE_CONSTRAINTS_INFO (type)) > + pedwarn (loc, OPT_Wpedantic, > + "structured binding declaration cannot have constrained " > + "%<auto%> type %qT", type); > inlinep = 0; > typedef_p = 0; > constexpr_p = 0; > --- gcc/testsuite/g++.dg/cpp2a/decomp5.C.jj 2022-11-16 10:39:20.469335601 +0100 > +++ gcc/testsuite/g++.dg/cpp2a/decomp5.C 2022-11-16 10:46:02.272896156 +0100 > @@ -0,0 +1,19 @@ > +// CWG2635 - Constrained structured bindings > +// { dg-do compile { target c++20 } } > + > +namespace std { > + template<typename T> struct tuple_size; > + template<int, typename> struct tuple_element; > +} > + > +struct A { > + int i; > + A(int x) : i(x) {} > + template <int I> int& get() { return i; } > +}; > + > +template<> struct std::tuple_size<A> { static const int value = 2; }; > +template<int I> struct std::tuple_element<I,A> { using type = int; }; > + > +template<class T> concept C = true; > +C auto [x, y] = A{1}; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C<<placeholder>, >\\\]'" } > --- gcc/testsuite/g++.dg/cpp2a/decomp6.C.jj 2022-11-16 10:46:44.868319518 +0100 > +++ gcc/testsuite/g++.dg/cpp2a/decomp6.C 2022-11-16 10:47:07.485013348 +0100 > @@ -0,0 +1,20 @@ > +// CWG2635 - Constrained structured bindings > +// { dg-do compile { target c++20 } } > +// { dg-options "-pedantic" } > + > +namespace std { > + template<typename T> struct tuple_size; > + template<int, typename> struct tuple_element; > +} > + > +struct A { > + int i; > + A(int x) : i(x) {} > + template <int I> int& get() { return i; } > +}; > + > +template<> struct std::tuple_size<A> { static const int value = 2; }; > +template<int I> struct std::tuple_element<I,A> { using type = int; }; > + > +template<class T> concept C = true; > +C auto [x, y] = A{1}; // { dg-warning "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C<<placeholder>, >\\\]'" } > --- gcc/testsuite/g++.dg/cpp2a/decomp7.C.jj 2022-11-16 10:47:14.578917309 +0100 > +++ gcc/testsuite/g++.dg/cpp2a/decomp7.C 2022-11-16 10:47:32.061680633 +0100 > @@ -0,0 +1,20 @@ > +// CWG2635 - Constrained structured bindings > +// { dg-do compile { target c++20 } } > +// { dg-options "-Wno-pedantic" } > + > +namespace std { > + template<typename T> struct tuple_size; > + template<int, typename> struct tuple_element; > +} > + > +struct A { > + int i; > + A(int x) : i(x) {} > + template <int I> int& get() { return i; } > +}; > + > +template<> struct std::tuple_size<A> { static const int value = 2; }; > +template<int I> struct std::tuple_element<I,A> { using type = int; }; > + > +template<class T> concept C = true; > +C auto [x, y] = A{1}; // { dg-bogus "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C<<placeholder>, >\\\]'" } > --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder7.C.jj 2022-11-13 17:53:46.037681901 +0100 > +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder7.C 2022-11-16 11:09:56.092513219 +0100 > @@ -7,16 +7,18 @@ template <class> > void f() { > int x[] = {1,2}; > int y[] = {3}; > - C1 auto [a,b] = x; > - C1 auto [c] = y; // { dg-error "constraints" } > + C1 auto [a,b] = x; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } > + C1 auto [c] = y; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } > + // { dg-error "constraints" "" { target *-*-* } .-1 } > } > > template <class T> > void g() { > T x[] = {1,2}; > T y[] = {3}; > - C1 auto [a,b] = x; > - C1 auto [c] = y; // { dg-error "constraints" } > + C1 auto [a,b] = x; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } > + C1 auto [c] = y; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'auto \\\[requires ::C1<<placeholder>, >\\\]'" } > + // { dg-error "constraints" "" { target *-*-* } .-1 } > } > template void g<int>(); > > @@ -27,6 +29,6 @@ struct S { int a, b; } s; > > template <class T> > void h() { > - const C2<T> auto& [a, b] = s; > + const C2<T> auto& [a, b] = s; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'const auto \\\[requires ::C2<<placeholder>, >\\\]'" } > } > template void h<int>(); > --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder8.C.jj 2022-11-13 17:53:46.037681901 +0100 > +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder8.C 2022-11-16 11:10:25.432116956 +0100 > @@ -5,6 +5,7 @@ template <class T> concept is_const = __ > void f() { > int x[] = {1,2}; > const int y[] = {3}; > - const is_const auto [a,b] = x; // { dg-error "constraints" } > - const is_const auto [c] = y; > + const is_const auto [a,b] = x; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'const auto \\\[requires ::is_const<<placeholder>, >\\\]'" } > + // { dg-error "constraints" "" { target *-*-* } .-1 } > + const is_const auto [c] = y; // { dg-error "structured binding declaration cannot have constrained 'auto' type 'const auto \\\[requires ::is_const<<placeholder>, >\\\]'" } > } > --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder9.C.jj 2022-11-16 10:49:54.610750873 +0100 > +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder9.C 2022-11-16 11:12:09.234715037 +0100 > @@ -0,0 +1,33 @@ > +// PR c++/99899 > +// { dg-do compile { target c++20 } } > +// { dg-options "-Wno-pedantic" } > + > +template <class T> concept C1 = sizeof(T) > sizeof(int[1]); > + > +template <class> > +void f() { > + int x[] = {1,2}; > + int y[] = {3}; > + C1 auto [a,b] = x; > + C1 auto [c] = y; // { dg-error "constraints" } > +} > + > +template <class T> > +void g() { > + T x[] = {1,2}; > + T y[] = {3}; > + C1 auto [a,b] = x; > + C1 auto [c] = y; // { dg-error "constraints" } > +} > +template void g<int>(); > + > + > +template <class... Ts> concept C2 = sizeof...(Ts) > 1; > + > +struct S { int a, b; } s; > + > +template <class T> > +void h() { > + const C2<T> auto& [a, b] = s; > +} > +template void h<int>(); > --- gcc/testsuite/g++.dg/cpp2a/concepts-placeholder10.C.jj 2022-11-16 10:49:54.610750873 +0100 > +++ gcc/testsuite/g++.dg/cpp2a/concepts-placeholder10.C 2022-11-16 10:50:16.757451058 +0100 > @@ -0,0 +1,11 @@ > +// { dg-do compile { target c++20 } } > +// { dg-options "-Wno-pedantic" } > + > +template <class T> concept is_const = __is_same(T, const T); > + > +void f() { > + int x[] = {1,2}; > + const int y[] = {3}; > + const is_const auto [a,b] = x; // { dg-error "constraints" } > + const is_const auto [c] = y; > +} > > Jakub > ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-11-16 13:12 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-11-12 11:23 [PATCH] c++: Implement CWG2635 - Constrained structured bindings Jakub Jelinek 2022-11-13 11:50 ` [PATCH] c++, v2: " Jakub Jelinek 2022-11-15 23:22 ` Jason Merrill 2022-11-16 10:17 ` [PATCH] c++, v3: " Jakub Jelinek 2022-11-16 13:12 ` Jason Merrill
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