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Implement LWG-3655: The INVOKE operation and union types #3495

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Merged
Stephan T. Lavavej (StephanTLavavej) merged 4 commits into from
Feb 26, 2023
Merged

Implement LWG-3655: The INVOKE operation and union types #3495

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63c9195
Implement LWG-3655: The `INVOKE` operation and `union` types
fsb4000 Feb 23, 2023
2b2dfc0
_Remove_cvref_t
fsb4000 Feb 23, 2023
3250c68
Rename to Union.
StephanTLavavej Feb 23, 2023
2eb2136
Verify that remove_cvref_t is used.
StephanTLavavej Feb 23, 2023
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6 changes: 4 additions & 2 deletions stl/inc/type_traits
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Original file line number Diff line number Diff line change
Expand Up @@ -1554,15 +1554,17 @@ struct _Invoker1;

template <class _Callable, class _Ty1, class _Removed_cvref>
struct _Invoker1<_Callable, _Ty1, _Removed_cvref, true, false>
: conditional_t<is_base_of_v<typename _Is_memfunptr<_Removed_cvref>::_Class_type, remove_reference_t<_Ty1>>,
: conditional_t<is_same_v<typename _Is_memfunptr<_Removed_cvref>::_Class_type, _Remove_cvref_t<_Ty1>>
|| is_base_of_v<typename _Is_memfunptr<_Removed_cvref>::_Class_type, _Remove_cvref_t<_Ty1>>,
_Invoker_pmf_object,
conditional_t<_Is_specialization_v<_Remove_cvref_t<_Ty1>, reference_wrapper>, _Invoker_pmf_refwrap,
_Invoker_pmf_pointer>> {}; // pointer to member function

template <class _Callable, class _Ty1, class _Removed_cvref>
struct _Invoker1<_Callable, _Ty1, _Removed_cvref, false, true>
: conditional_t<
is_base_of_v<typename _Is_member_object_pointer<_Removed_cvref>::_Class_type, remove_reference_t<_Ty1>>,
is_same_v<typename _Is_member_object_pointer<_Removed_cvref>::_Class_type, _Remove_cvref_t<_Ty1>>
|| is_base_of_v<typename _Is_member_object_pointer<_Removed_cvref>::_Class_type, _Remove_cvref_t<_Ty1>>,
_Invoker_pmd_object,
conditional_t<_Is_specialization_v<_Remove_cvref_t<_Ty1>, reference_wrapper>, _Invoker_pmd_refwrap,
_Invoker_pmd_pointer>> {}; // pointer to member data
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19 changes: 19 additions & 0 deletions tests/std/tests/P2136R3_invoke_r/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -109,6 +109,25 @@ constexpr bool test_invoke_r() {
return true;
}

// LWG-3655: The INVOKE operation and union types

@StephanTLavavej Stephan T. Lavavej (StephanTLavavej) Feb 23, 2023

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No change requested: this LWG issue resolution is being implemented unconditionally (as usual), but the test being extended here is C++23:

STL/tests/std/tests/P2136R3_invoke_r/env.lst

Line 4 in 86acfb1

RUNALL_INCLUDE ..\usual_latest_matrix.lst

This means that the product code is active for C++14/17/20, but is not being tested in those modes. We have tests that are built down to C++14 mode (e.g. Dev11_0535636_functional_overhaul is where INVOKE is mostly tested).

However, I don't think this coverage needs to be moved - even with my paranoia about compiler bugs, I find it hard to imagine a compiler bug that would affect this code that would appear only in C++14/17/20 mode. Also, it's slightly annoying to test anything here in C++14 mode as all that's available there is the older/deprecated result_of. So I'm simply noting this for future consideration.

union Union {
int x;
};
static_assert(is_invocable_v<int Union::*, Union>);
static_assert(is_invocable_v<int Union::*, Union&>);
static_assert(is_invocable_v<int Union::*, const Union>);
static_assert(is_invocable_v<int Union::*, const Union&>);

static_assert(is_invocable_v<void (Union::*)(), Union>);
static_assert(is_invocable_v<void (Union::*)(), Union&>);
static_assert(!is_invocable_v<void (Union::*)(), const Union>);
static_assert(!is_invocable_v<void (Union::*)(), const Union&>);

static_assert(is_invocable_v<void (Union::*)() const, Union>);
static_assert(is_invocable_v<void (Union::*)() const, Union&>);
static_assert(is_invocable_v<void (Union::*)() const, const Union>);
static_assert(is_invocable_v<void (Union::*)() const, const Union&>);

int main() {
test_invoke_r();
STATIC_ASSERT(test_invoke_r());
Expand Down