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* [Bug c++/100374] New: Type-constraints of member function templates should not be substituted into during implicit instantiation
@ 2021-05-01 13:48 rs2740 at gmail dot com
2021-05-03 15:20 ` [Bug c++/100374] " ppalka at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: rs2740 at gmail dot com @ 2021-05-01 13:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100374
Bug ID: 100374
Summary: Type-constraints of member function templates should
not be substituted into during implicit instantiation
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Keywords: rejects-valid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: rs2740 at gmail dot com
Target Milestone: ---
template<class T, class U>
concept C = true;
template <class T>
struct Foo
{
template <C<typename T::value_type> U>
void bar()
{
}
};
Foo<float> f;
GCC trunk with -std=c++20 produces:
<source>: In instantiation of 'struct Foo<float>':
<source>:13:12: required from here
<source>:8:8: error: 'float' is not a class, struct, or union type
8 | void bar()
| ^~~
[temp.inst]/17 says that type-constraints like C<typename T::value_type> should
not be substituted into during the implicit instantiation of the declaration of
Foo<float>::bar:
The type-constraints and requires-clause of a template specialization or member
function are not instantiated along with the specialization or function itself,
even for a member function of a local class; substitution into the atomic
constraints formed from them is instead performed as specified in
[temp.constr.decl] and [temp.constr.atomic] when determining whether the
constraints are satisfied or as specified in [temp.constr.decl] when comparing
declarations.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/100374] Type-constraints of member function templates should not be substituted into during implicit instantiation
2021-05-01 13:48 [Bug c++/100374] New: Type-constraints of member function templates should not be substituted into during implicit instantiation rs2740 at gmail dot com
@ 2021-05-03 15:20 ` ppalka at gcc dot gnu.org
2022-05-27 18:40 ` ppalka at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-05-03 15:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100374
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
CC| |ppalka at gcc dot gnu.org
Status|UNCONFIRMED |NEW
Last reconfirmed| |2021-05-03
--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/100374] Type-constraints of member function templates should not be substituted into during implicit instantiation
2021-05-01 13:48 [Bug c++/100374] New: Type-constraints of member function templates should not be substituted into during implicit instantiation rs2740 at gmail dot com
2021-05-03 15:20 ` [Bug c++/100374] " ppalka at gcc dot gnu.org
@ 2022-05-27 18:40 ` ppalka at gcc dot gnu.org
2022-06-03 13:29 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2022-05-27 18:40 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100374
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |ppalka at gcc dot gnu.org
Status|NEW |ASSIGNED
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/100374] Type-constraints of member function templates should not be substituted into during implicit instantiation
2021-05-01 13:48 [Bug c++/100374] New: Type-constraints of member function templates should not be substituted into during implicit instantiation rs2740 at gmail dot com
2021-05-03 15:20 ` [Bug c++/100374] " ppalka at gcc dot gnu.org
2022-05-27 18:40 ` ppalka at gcc dot gnu.org
@ 2022-06-03 13:29 ` cvs-commit at gcc dot gnu.org
2022-07-21 16:48 ` cvs-commit at gcc dot gnu.org
2022-07-21 16:49 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-06-03 13:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100374
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:
https://gcc.gnu.org/g:43c013df02fdb07f9b7a5e7e6669e6d69769d451
commit r13-981-g43c013df02fdb07f9b7a5e7e6669e6d69769d451
Author: Patrick Palka <ppalka@redhat.com>
Date: Fri Jun 3 09:29:12 2022 -0400
c++: don't substitute TEMPLATE_PARM_CONSTRAINTS [PR100374]
This patch makes us avoid substituting into the TEMPLATE_PARM_CONSTRAINTS
of each template parameter except as necessary for declaration matching,
like we already do for the other constituent constraints of a declaration.
This patch also improves the CA104 implementation of explicit
specialization matching of a constrained function template inside a
class template, by considering the function's combined constraints
instead of just its trailing constraints. This allows us to correctly
handle the first three explicit specializations in concepts-spec2.C
below, but because we compare the constraints as a whole, it means we
incorrectly accept the fourth explicit specialization which writes #3's
constraints in a different way. For complete correctness here,
determine_specialization should use tsubst_each_template_parm_constraints
and template_parameter_heads_equivalent_p.
PR c++/100374
gcc/cp/ChangeLog:
* pt.cc (determine_specialization): Compare overall constraints
not just the trailing constraints.
(tsubst_each_template_parm_constraints): Define.
(tsubst_friend_function): Use it.
(tsubst_friend_class): Use it.
(tsubst_template_parm): Don't substitute TEMPLATE_PARM_CONSTRAINTS.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-spec2.C: New test.
* g++.dg/cpp2a/concepts-template-parm11.C: New test.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/100374] Type-constraints of member function templates should not be substituted into during implicit instantiation
2021-05-01 13:48 [Bug c++/100374] New: Type-constraints of member function templates should not be substituted into during implicit instantiation rs2740 at gmail dot com
` (2 preceding siblings ...)
2022-06-03 13:29 ` cvs-commit at gcc dot gnu.org
@ 2022-07-21 16:48 ` cvs-commit at gcc dot gnu.org
2022-07-21 16:49 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-07-21 16:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100374
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:
https://gcc.gnu.org/g:90655e30130f8f609911335902db3c8354a5e21a
commit r12-8602-g90655e30130f8f609911335902db3c8354a5e21a
Author: Patrick Palka <ppalka@redhat.com>
Date: Fri Jun 3 09:29:12 2022 -0400
c++: don't substitute TEMPLATE_PARM_CONSTRAINTS [PR100374]
This patch makes us avoid substituting into the TEMPLATE_PARM_CONSTRAINTS
of each template parameter except as necessary for declaration matching,
like we already do for the other constituent constraints of a declaration.
This patch also improves the CA104 implementation of explicit
specialization matching of a constrained function template inside a
class template, by considering the function's combined constraints
instead of just its trailing constraints. This allows us to correctly
handle the first three explicit specializations in concepts-spec2.C
below, but because we compare the constraints as a whole, it means we
incorrectly accept the fourth explicit specialization which writes #3's
constraints in a different way. For complete correctness here,
determine_specialization should use tsubst_each_template_parm_constraints
and template_parameter_heads_equivalent_p.
PR c++/100374
gcc/cp/ChangeLog:
* pt.cc (determine_specialization): Compare overall constraints
not just the trailing constraints.
(tsubst_each_template_parm_constraints): Define.
(tsubst_friend_function): Use it.
(tsubst_friend_class): Use it.
(tsubst_template_parm): Don't substitute TEMPLATE_PARM_CONSTRAINTS.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-spec2.C: New test.
* g++.dg/cpp2a/concepts-template-parm11.C: New test.
(cherry picked from commit 43c013df02fdb07f9b7a5e7e6669e6d69769d451)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/100374] Type-constraints of member function templates should not be substituted into during implicit instantiation
2021-05-01 13:48 [Bug c++/100374] New: Type-constraints of member function templates should not be substituted into during implicit instantiation rs2740 at gmail dot com
` (3 preceding siblings ...)
2022-07-21 16:48 ` cvs-commit at gcc dot gnu.org
@ 2022-07-21 16:49 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2022-07-21 16:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100374
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |12.2
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 12.2/13
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-05-01 13:48 [Bug c++/100374] New: Type-constraints of member function templates should not be substituted into during implicit instantiation rs2740 at gmail dot com
2021-05-03 15:20 ` [Bug c++/100374] " ppalka at gcc dot gnu.org
2022-05-27 18:40 ` ppalka at gcc dot gnu.org
2022-06-03 13:29 ` cvs-commit at gcc dot gnu.org
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