[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
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// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++1z -triple=x86_64-linux-gnu
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template <typename U, typename V>
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struct S1 {
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static constexpr const bool value = false;
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};
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template <typename U, typename V>
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inline constexpr bool global_inline_var = S1<U, V>::value;
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template <typename T>
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struct S2 {
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template <typename U, typename V>
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static inline constexpr bool var = global_inline_var<U, V>;
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};
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template <typename U, typename V>
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void foo() {
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static_assert(S1<U, V>::value);
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// expected-error@-1{{static_assert failed due to requirement 'S1<int, float>::value'}}
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}
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template void foo<int, float>();
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// expected-note@-1{{in instantiation of function template specialization 'foo<int, float>' requested here}}
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template <typename U, typename V>
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void foo2() {
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static_assert(global_inline_var<U, V>);
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// expected-error@-1{{static_assert failed due to requirement 'global_inline_var<int, float>'}}
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}
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template void foo2<int, float>();
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// expected-note@-1{{in instantiation of function template specialization 'foo2<int, float>' requested here}}
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template <typename T, typename U, typename V>
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void foo3() {
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static_assert(T::template var<U, V>);
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// expected-error@-1{{static_assert failed due to requirement 'S2<long>::var<int, float>'}}
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}
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template void foo3<S2<long>, int, float>();
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// expected-note@-1{{in instantiation of function template specialization 'foo3<S2<long>, int, float>' requested here}}
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template <typename T>
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void foo4() {
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static_assert(S1<T[sizeof(T)], int[4]>::value, "");
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// expected-error@-1{{static_assert failed due to requirement 'S1<float [4], int [4]>::value'}}
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};
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template void foo4<float>();
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// expected-note@-1{{in instantiation of function template specialization 'foo4<float>' requested here}}
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2018-12-11 16:39:11 +08:00
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template <typename U, typename V>
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void foo5() {
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static_assert(!!(global_inline_var<U, V>));
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// expected-error@-1{{static_assert failed due to requirement '!!(global_inline_var<int, float>)'}}
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}
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template void foo5<int, float>();
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// expected-note@-1{{in instantiation of function template specialization 'foo5<int, float>' requested here}}
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