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Workaround for the interaction of constraints in expected and explicit template instantiation in permissive modes #4658

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Merged
StephanTLavavej merged 6 commits into from
May 20, 2024
Merged

Workaround for the interaction of constraints in expected and explicit template instantiation in permissive modes #4658

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2842a08
Workaround for DevCom-10652420
frederick-vs-ja May 6, 2024
4dfdfd7
Change the comments as DevCom-10652420 is closed as Not a Bug
frederick-vs-ja May 9, 2024
a7cea5f
`<locale>` is unused.
StephanTLavavej May 15, 2024
5c6389c
Mark workarounds with `// ^^^ workaround ^^^`.
StephanTLavavej May 15, 2024
420e316
Fix arrow comment.
StephanTLavavej May 15, 2024
7f66a89
Restore the inclusion of `<locale>` and explain its reason.
frederick-vs-ja May 15, 2024
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17 changes: 15 additions & 2 deletions stl/inc/expected
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Original file line number Diff line number Diff line change
Expand Up @@ -87,7 +87,11 @@ public:
}

friend constexpr void swap(unexpected& _Left, unexpected& _Right) noexcept(is_nothrow_swappable_v<_Err>)
#if defined(__clang__) || defined(__EDG__) // TRANSITION, /permissive
requires is_swappable_v<_Err>
#else // ^^^ no workaround / workaround vvv
requires is_swappable<_Err>::value
#endif // ^^^ workaround ^^^
{
_Left.swap(_Right);
}
Expand Down Expand Up @@ -601,7 +605,11 @@ public:
friend constexpr void swap(expected& _Lhs, expected& _Rhs) noexcept(
is_nothrow_move_constructible_v<_Ty> && is_nothrow_swappable_v<_Ty> && is_nothrow_move_constructible_v<_Err>
&& is_nothrow_swappable_v<_Err>)
requires is_swappable_v<_Ty> && is_swappable_v<_Err> //
#if defined(__clang__) || defined(__EDG__) // TRANSITION, /permissive
requires is_swappable_v<_Ty> && is_swappable_v<_Err>
#else // ^^^ no workaround / workaround vvv
requires is_swappable<_Ty>::value && is_swappable<_Err>::value
#endif // ^^^ workaround ^^^
&& is_move_constructible_v<_Ty> && is_move_constructible_v<_Err>
&& (is_nothrow_move_constructible_v<_Ty> || is_nothrow_move_constructible_v<_Err>)
{
Expand Down Expand Up @@ -1429,7 +1437,12 @@ public:

friend constexpr void swap(expected& _Left, expected& _Right) noexcept(
is_nothrow_move_constructible_v<_Err> && is_nothrow_swappable_v<_Err>)
requires is_swappable_v<_Err> && is_move_constructible_v<_Err>
#if defined(__clang__) || defined(__EDG__) // TRANSITION, /permissive
requires is_swappable_v<_Err>
#else // ^^^ no workaround / workaround vvv
requires is_swappable<_Err>::value
#endif // ^^^ workaround ^^^
&& is_move_constructible_v<_Err>
{
_Left.swap(_Right);
}
Expand Down
10 changes: 10 additions & 0 deletions stl/inc/iterator
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Expand Up @@ -498,6 +498,11 @@ _NODISCARD bool operator!=(
}
#endif // !_HAS_CXX20

#if _HAS_CXX20 && !defined(__clang__) && !defined(__EDG__) // TRANSITION, /permissive, avoid checking constraints
template <class _Elem, class _Traits>
constexpr bool _Iterator_is_contiguous<istreambuf_iterator<_Elem, _Traits>> = false;
#endif // ^^^ workaround ^^^

_EXPORT_STD template <class _Elem, class _Traits>
class ostreambuf_iterator {
public:
Expand Down Expand Up @@ -548,6 +553,11 @@ private:
streambuf_type* _Strbuf;
};

#if _HAS_CXX20 && !defined(__clang__) && !defined(__EDG__) // TRANSITION, /permissive, avoid checking constraints
template <class _Elem, class _Traits>
constexpr bool _Iterator_is_contiguous<ostreambuf_iterator<_Elem, _Traits>> = false;
#endif // ^^^ workaround ^^^

#if _HAS_CXX20
enum class _Variantish_state : unsigned char { _Nothing, _Holds_first, _Holds_second };

Expand Down
1 change: 1 addition & 0 deletions tests/std/test.lst
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Expand Up @@ -245,6 +245,7 @@ tests\GH_004388_unordered_meow_operator_equal
tests\GH_004477_mdspan_warning_5246
tests\GH_004618_mixed_operator_usage_keeps_statistical_properties
tests\GH_004618_normal_distribution_avoids_resets
tests\GH_004657_expected_constraints_permissive
tests\LWG2381_num_get_floating_point
tests\LWG2597_complex_branch_cut
tests\LWG3018_shared_ptr_function
Expand Down
4 changes: 4 additions & 0 deletions tests/std/tests/GH_004657_expected_constraints_permissive/env.lst
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@@ -0,0 +1,4 @@
# Copyright (c) Microsoft Corporation.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

RUNALL_INCLUDE ..\usual_latest_matrix.lst
27 changes: 27 additions & 0 deletions tests/std/tests/GH_004657_expected_constraints_permissive/test.compile.pass.cpp
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@@ -0,0 +1,27 @@
// Copyright (c) Microsoft Corporation.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#include <expected>
// <locale> provides several explicit template instantiation definitions that might break constraints checking
// and hence cause errors in /permissive modes.
#include <locale>
#include <string>
#include <utility>

using namespace std;

expected<int, string> test_expected_int_constraints() {
return 42;
}

expected<pair<int, int>, string> test_expected_pair_constraints() {
return pair<int, int>{42, 1729};
}

expected<void, string> test_expected_void_constraints() {
return {};
}

unexpected<string> test_unexpected_constraints() {
return unexpected<string>{string{}};
}
2 changes: 1 addition & 1 deletion tests/std/tests/P0323R12_expected/env.lst
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@@ -1,4 +1,4 @@
# Copyright (c) Microsoft Corporation.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

RUNALL_INCLUDE ..\strict_latest_matrix.lst
RUNALL_INCLUDE ..\usual_latest_matrix.lst
48 changes: 25 additions & 23 deletions tests/std/tests/P0323R12_expected/test.cpp
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Expand Up @@ -12,6 +12,8 @@
#include <utility>
#include <vector>

#include <is_permissive.hpp> // noexcept operator possibly gives wrong values in permissive modes

using namespace std;

enum class IsDefaultConstructible : bool { Not, Yes };
Expand Down Expand Up @@ -82,31 +84,31 @@ namespace test_unexpected {
// [expected.un.ctor]
const int& input = 1;
Unexpect in_place_lvalue_constructed{in_place, input};
static_assert(noexcept(Unexpect{in_place, input}) == copy_construction_is_noexcept);
static_assert(noexcept(Unexpect{in_place, input}) == copy_construction_is_noexcept || is_permissive);
assert(in_place_lvalue_constructed == Unexpect{test_error{1}});

Unexpect in_place_rvalue_constructed{in_place, 42};
static_assert(noexcept(Unexpect{in_place, 42}) == move_construction_is_noexcept);
static_assert(noexcept(Unexpect{in_place, 42}) == move_construction_is_noexcept || is_permissive);
assert(in_place_rvalue_constructed == Unexpect{test_error{42}});

Unexpect in_place_ilist_lvalue_constructed{in_place, {2}, input};
static_assert(noexcept(Unexpect{in_place, {2}, input}) == copy_construction_is_noexcept);
static_assert(noexcept(Unexpect{in_place, {2}, input}) == copy_construction_is_noexcept || is_permissive);
assert(in_place_ilist_lvalue_constructed == Unexpect{test_error{1}});

Unexpect in_place_ilist_rvalue_constructed{in_place, {2}, 1337};
static_assert(noexcept(Unexpect{in_place, {2}, 1337}) == move_construction_is_noexcept);
static_assert(noexcept(Unexpect{in_place, {2}, 1337}) == move_construction_is_noexcept || is_permissive);
assert(in_place_ilist_rvalue_constructed == Unexpect{test_error{1337}});

Unexpect base_error_constructed{test_error{3}};
static_assert(noexcept(Unexpect{test_error{3}}) == move_construction_is_noexcept);
static_assert(noexcept(Unexpect{test_error{3}}) == move_construction_is_noexcept || is_permissive);
assert(base_error_constructed.error()._val == 3);

Unexpect conversion_error_constructed{convertible{4}};
static_assert(noexcept(Unexpect{convertible{4}}) == move_construction_is_noexcept);
static_assert(noexcept(Unexpect{convertible{4}}) == move_construction_is_noexcept || is_permissive);
assert(conversion_error_constructed.error()._val == 4);

Unexpect brace_error_constructed{{5}};
static_assert(noexcept(Unexpect{{5}}) == move_construction_is_noexcept);
static_assert(noexcept(Unexpect{{5}}) == move_construction_is_noexcept || is_permissive);
assert(brace_error_constructed.error()._val == 5);

// [expected.un.eq]
Expand Down Expand Up @@ -500,12 +502,12 @@ namespace test_expected {
const Expected copy_constructed_value{const_input_value};
assert(copy_constructed_value);
assert(copy_constructed_value.value() == 3);
static_assert(noexcept(Expected{const_input_value}) == should_be_noexcept);
static_assert(noexcept(Expected{const_input_value}) == should_be_noexcept || is_permissive);

const Expected move_constructed_value{Input{}};
assert(move_constructed_value);
assert(move_constructed_value.value() == 42);
static_assert(noexcept(Expected{Input{}}) == should_be_noexcept);
static_assert(noexcept(Expected{Input{}}) == should_be_noexcept || is_permissive);

const Expected brace_constructed_value{{}};
assert(brace_constructed_value);
Expand All @@ -528,7 +530,7 @@ namespace test_expected {
const Expected move_constructed_value{Input{in_place}};
assert(move_constructed_value);
assert(move_constructed_value.value() == 42);
static_assert(noexcept(Expected{Input{in_place}}) == should_be_noexcept);
static_assert(noexcept(Expected{Input{in_place}}) == should_be_noexcept || is_permissive);

const Input const_input_error{unexpect};
const Expected copy_constructed_error{const_input_error};
Expand All @@ -539,7 +541,7 @@ namespace test_expected {
const Expected move_constructed_error{Input{unexpect}};
assert(!move_constructed_error);
assert(move_constructed_error.error() == 42);
static_assert(noexcept(Expected{Input{unexpect}}) == should_be_noexcept);
static_assert(noexcept(Expected{Input{unexpect}}) == should_be_noexcept || is_permissive);
}

{ // converting from unexpected
Expand All @@ -550,12 +552,12 @@ namespace test_expected {
const Expected copy_constructed{const_input};
assert(!copy_constructed);
assert(copy_constructed.error() == 3);
static_assert(noexcept(Expected{const_input}) == should_be_noexcept);
static_assert(noexcept(Expected{const_input}) == should_be_noexcept || is_permissive);

const Expected move_constructed{Input{in_place}};
assert(!move_constructed);
assert(move_constructed.error() == 42);
static_assert(noexcept(Expected{Input{in_place}}) == should_be_noexcept);
static_assert(noexcept(Expected{Input{in_place}}) == should_be_noexcept || is_permissive);
}

{ // in place payload
Expand All @@ -568,12 +570,12 @@ namespace test_expected {
const Expected value_constructed{in_place, convertible{}};
assert(value_constructed);
assert(value_constructed.value() == 42);
static_assert(noexcept(Expected{in_place, convertible{}}) == should_be_noexcept);
static_assert(noexcept(Expected{in_place, convertible{}}) == should_be_noexcept || is_permissive);

const Expected ilist_value_constructed{in_place, {1}, convertible{}};
assert(ilist_value_constructed);
assert(ilist_value_constructed.value() == 1337);
static_assert(noexcept(Expected{in_place, {1}, convertible{}}) == should_be_noexcept);
static_assert(noexcept(Expected{in_place, {1}, convertible{}}) == should_be_noexcept || is_permissive);
}

{ // in place error
Expand All @@ -586,12 +588,12 @@ namespace test_expected {
const Expected value_constructed{unexpect, convertible{}};
assert(!value_constructed);
assert(value_constructed.error() == 42);
static_assert(noexcept(Expected{unexpect, convertible{}}) == should_be_noexcept);
static_assert(noexcept(Expected{unexpect, convertible{}}) == should_be_noexcept || is_permissive);

const Expected ilist_value_constructed{unexpect, {1}, convertible{}};
assert(!ilist_value_constructed);
assert(ilist_value_constructed.error() == 1337);
static_assert(noexcept(Expected{unexpect, {1}, convertible{}}) == should_be_noexcept);
static_assert(noexcept(Expected{unexpect, {1}, convertible{}}) == should_be_noexcept || is_permissive);
}

{ // expected<void, E>: converting from different expected
Expand All @@ -609,7 +611,7 @@ namespace test_expected {
const Expected move_constructed_value{Input{in_place}};
assert(move_constructed_value);
move_constructed_value.value();
static_assert(noexcept(Expected{Input{in_place}}) == should_be_noexcept);
static_assert(noexcept(Expected{Input{in_place}}) == should_be_noexcept || is_permissive);

const Input const_input_error{unexpect};
const Expected copy_constructed_error{const_input_error};
Expand All @@ -620,7 +622,7 @@ namespace test_expected {
const Expected move_constructed_error{Input{unexpect}};
assert(!move_constructed_error);
assert(move_constructed_error.error() == 42);
static_assert(noexcept(Expected{Input{unexpect}}) == should_be_noexcept);
static_assert(noexcept(Expected{Input{unexpect}}) == should_be_noexcept || is_permissive);
}

{ // expected<void, E>: converting from unexpected
Expand All @@ -631,12 +633,12 @@ namespace test_expected {
const Expected copy_constructed{const_input};
assert(!copy_constructed);
assert(copy_constructed.error() == 3);
static_assert(noexcept(Expected{const_input}) == should_be_noexcept);
static_assert(noexcept(Expected{const_input}) == should_be_noexcept || is_permissive);

const Expected move_constructed{Input{in_place}};
assert(!move_constructed);
assert(move_constructed.error() == 42);
static_assert(noexcept(Expected{Input{in_place}}) == should_be_noexcept);
static_assert(noexcept(Expected{Input{in_place}}) == should_be_noexcept || is_permissive);
}

{ // expected<void, E>: in place payload
Expand All @@ -657,12 +659,12 @@ namespace test_expected {
const Expected value_constructed{unexpect, convertible{}};
assert(!value_constructed);
assert(value_constructed.error() == 42);
static_assert(noexcept(Expected{unexpect, convertible{}}) == should_be_noexcept);
static_assert(noexcept(Expected{unexpect, convertible{}}) == should_be_noexcept || is_permissive);

const Expected ilist_value_constructed{unexpect, {1}, convertible{}};
assert(!ilist_value_constructed);
assert(ilist_value_constructed.error() == 1337);
static_assert(noexcept(Expected{unexpect, {1}, convertible{}}) == should_be_noexcept);
static_assert(noexcept(Expected{unexpect, {1}, convertible{}}) == should_be_noexcept || is_permissive);
}
}

Expand Down