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llvm-project/clang/test/SemaCXX/static-assert-cxx17.cpp

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[WIP][Sema] Improve static_assert diagnostics for type traits. Summary: In our codebase, `static_assert(std::some_type_trait<Ts...>::value, "msg")` (where `some_type_trait` is an std type_trait and `Ts...` is the appropriate template parameters) account for 11.2% of the `static_assert`s. In these cases, the `Ts` are typically not spelled out explicitly, e.g. `static_assert(std::is_same<SomeT::TypeT, typename SomeDependentT::value_type>::value, "message");` The diagnostic when the assert fails is typically not very useful, e.g. `static_assert failed due to requirement 'std::is_same<SomeT::TypeT, typename SomeDependentT::value_type>::value' "message"` This change makes the diagnostic spell out the types explicitly , e.g. `static_assert failed due to requirement 'std::is_same<int, float>::value' "message"` See tests for more examples. After this is submitted, I intend to handle `static_assert(!std::some_type_trait<Ts...>::value, "msg")`, which is another 6.6% of static_asserts. Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D54903 llvm-svn: 348239
2018-12-04 15:59:57 +08:00
// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++1z -triple=x86_64-linux-gnu
template <typename U, typename V>
struct S1 {
static constexpr const bool value = false;
};
template <typename U, typename V>
inline constexpr bool global_inline_var = S1<U, V>::value;
template <typename T>
struct S2 {
template <typename U, typename V>
static inline constexpr bool var = global_inline_var<U, V>;
};
template <typename U, typename V>
void foo() {
static_assert(S1<U, V>::value);
// expected-error@-1{{static_assert failed due to requirement 'S1<int, float>::value'}}
}
template void foo<int, float>();
// expected-note@-1{{in instantiation of function template specialization 'foo<int, float>' requested here}}
template <typename U, typename V>
void foo2() {
static_assert(global_inline_var<U, V>);
// expected-error@-1{{static_assert failed due to requirement 'global_inline_var<int, float>'}}
}
template void foo2<int, float>();
// expected-note@-1{{in instantiation of function template specialization 'foo2<int, float>' requested here}}
template <typename T, typename U, typename V>
void foo3() {
static_assert(T::template var<U, V>);
// expected-error@-1{{static_assert failed due to requirement 'S2<long>::var<int, float>'}}
}
template void foo3<S2<long>, int, float>();
// expected-note@-1{{in instantiation of function template specialization 'foo3<S2<long>, int, float>' requested here}}
template <typename T>
void foo4() {
static_assert(S1<T[sizeof(T)], int[4]>::value, "");
// expected-error@-1{{static_assert failed due to requirement 'S1<float [4], int [4]>::value'}}
};
template void foo4<float>();
// expected-note@-1{{in instantiation of function template specialization 'foo4<float>' requested here}}