diff options
| -rw-r--r-- | libstdc++-v3/ChangeLog | 8 | ||||
| -rw-r--r-- | libstdc++-v3/include/std/variant | 44 |
2 files changed, 36 insertions, 16 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 1ba66d8..d310cb0 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,5 +1,13 @@ 2019-05-17 Jonathan Wakely <jwakely@redhat.com> + PR libstdc++/90246 + * include/std/variant (holds_alternative, get, get_if): Improve + static assertion messages. + (bad_variant_access::bad_variant_access()): Change default message. + (__throw_bad_variant_access(bool)): New overload. + (get): Use new overload. + (visit, visit<R>): Improve exception message. + * testsuite/20_util/variant/compile.cc: Fix narrowing test for ILP32 targets. Add more cases from P0608R3. * testsuite/20_util/variant/run.cc: Add more cases from P0608R3. diff --git a/libstdc++-v3/include/std/variant b/libstdc++-v3/include/std/variant index eec41750..60472b4 100644 --- a/libstdc++-v3/include/std/variant +++ b/libstdc++-v3/include/std/variant @@ -1065,7 +1065,7 @@ namespace __variant holds_alternative(const variant<_Types...>& __v) noexcept { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, - "T should occur for exactly once in alternatives"); + "T must occur exactly once in alternatives"); return __v.index() == __detail::__variant::__index_of_v<_Tp, _Types...>; } @@ -1073,7 +1073,7 @@ namespace __variant constexpr _Tp& get(variant<_Types...>& __v) { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, - "T should occur for exactly once in alternatives"); + "T must occur exactly once in alternatives"); static_assert(!is_void_v<_Tp>, "_Tp should not be void"); return std::get<__detail::__variant::__index_of_v<_Tp, _Types...>>(__v); } @@ -1082,7 +1082,7 @@ namespace __variant constexpr _Tp&& get(variant<_Types...>&& __v) { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, - "T should occur for exactly once in alternatives"); + "T must occur exactly once in alternatives"); static_assert(!is_void_v<_Tp>, "_Tp should not be void"); return std::get<__detail::__variant::__index_of_v<_Tp, _Types...>>( std::move(__v)); @@ -1092,7 +1092,7 @@ namespace __variant constexpr const _Tp& get(const variant<_Types...>& __v) { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, - "T should occur for exactly once in alternatives"); + "T must occur exactly once in alternatives"); static_assert(!is_void_v<_Tp>, "_Tp should not be void"); return std::get<__detail::__variant::__index_of_v<_Tp, _Types...>>(__v); } @@ -1101,7 +1101,7 @@ namespace __variant constexpr const _Tp&& get(const variant<_Types...>&& __v) { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, - "T should occur for exactly once in alternatives"); + "T must occur exactly once in alternatives"); static_assert(!is_void_v<_Tp>, "_Tp should not be void"); return std::get<__detail::__variant::__index_of_v<_Tp, _Types...>>( std::move(__v)); @@ -1139,7 +1139,7 @@ namespace __variant get_if(variant<_Types...>* __ptr) noexcept { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, - "T should occur for exactly once in alternatives"); + "T must occur exactly once in alternatives"); static_assert(!is_void_v<_Tp>, "_Tp should not be void"); return std::get_if<__detail::__variant::__index_of_v<_Tp, _Types...>>( __ptr); @@ -1150,7 +1150,7 @@ namespace __variant get_if(const variant<_Types...>* __ptr) noexcept { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, - "T should occur for exactly once in alternatives"); + "T must occur exactly once in alternatives"); static_assert(!is_void_v<_Tp>, "_Tp should not be void"); return std::get_if<__detail::__variant::__index_of_v<_Tp, _Types...>>( __ptr); @@ -1213,22 +1213,34 @@ namespace __variant class bad_variant_access : public exception { public: - bad_variant_access() noexcept : _M_reason("Unknown reason") { } + bad_variant_access() noexcept { } + const char* what() const noexcept override { return _M_reason; } private: - bad_variant_access(const char* __reason) : _M_reason(__reason) { } + bad_variant_access(const char* __reason) noexcept : _M_reason(__reason) { } - const char* _M_reason; + // Must point to a string with static storage duration: + const char* _M_reason = "bad variant access"; friend void __throw_bad_variant_access(const char* __what); }; + // Must only be called with a string literal inline void __throw_bad_variant_access(const char* __what) { _GLIBCXX_THROW_OR_ABORT(bad_variant_access(__what)); } + inline void + __throw_bad_variant_access(bool __valueless) + { + if (__valueless) [[__unlikely__]] + __throw_bad_variant_access("std::get: variant is valueless"); + else + __throw_bad_variant_access("std::get: wrong index for variant"); + } + template<typename... _Types> class variant : private __detail::__variant::_Variant_base<_Types...>, @@ -1592,7 +1604,7 @@ namespace __variant static_assert(_Np < sizeof...(_Types), "The index should be in [0, number of alternatives)"); if (__v.index() != _Np) - __throw_bad_variant_access("Unexpected index"); + __throw_bad_variant_access(__v.valueless_by_exception()); return __detail::__variant::__get<_Np>(__v); } @@ -1603,7 +1615,7 @@ namespace __variant static_assert(_Np < sizeof...(_Types), "The index should be in [0, number of alternatives)"); if (__v.index() != _Np) - __throw_bad_variant_access("Unexpected index"); + __throw_bad_variant_access(__v.valueless_by_exception()); return __detail::__variant::__get<_Np>(std::move(__v)); } @@ -1614,7 +1626,7 @@ namespace __variant static_assert(_Np < sizeof...(_Types), "The index should be in [0, number of alternatives)"); if (__v.index() != _Np) - __throw_bad_variant_access("Unexpected index"); + __throw_bad_variant_access(__v.valueless_by_exception()); return __detail::__variant::__get<_Np>(__v); } @@ -1625,7 +1637,7 @@ namespace __variant static_assert(_Np < sizeof...(_Types), "The index should be in [0, number of alternatives)"); if (__v.index() != _Np) - __throw_bad_variant_access("Unexpected index"); + __throw_bad_variant_access(__v.valueless_by_exception()); return __detail::__variant::__get<_Np>(std::move(__v)); } @@ -1646,7 +1658,7 @@ namespace __variant visit(_Visitor&& __visitor, _Variants&&... __variants) { if ((__variants.valueless_by_exception() || ...)) - __throw_bad_variant_access("Unexpected index"); + __throw_bad_variant_access("std::visit: variant is valueless"); using _Result_type = std::invoke_result_t<_Visitor, decltype(std::get<0>(std::declval<_Variants>()))...>; @@ -1663,7 +1675,7 @@ namespace __variant visit(_Visitor&& __visitor, _Variants&&... __variants) { if ((__variants.valueless_by_exception() || ...)) - __throw_bad_variant_access("Unexpected index"); + __throw_bad_variant_access("std::visit<R>: variant is valueless"); return std::__do_visit<_Res>(std::forward<_Visitor>(__visitor), std::forward<_Variants>(__variants)...); |