teak-llvm/clang/test/SemaTemplate/cxx2a-constraint-caching.cpp
Saar Raz 67c608a969 [Concepts] Deprecate -fconcepts-ts, enable Concepts under -std=c++2a
Now with concepts support merged and mostly complete, we do not need -fconcepts-ts
(which was also misleading as we were not implementing the TS) and can enable
concepts features under C++2a. A warning will be generated if users still attempt
to use -fconcepts-ts.
2020-01-24 00:48:59 +02:00

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// RUN: %clang_cc1 -std=c++2a -verify %s
// RUN: %clang_cc1 -std=c++2a -verify %s -fno-concept-satisfaction-caching -DNO_CACHE
// expected-no-diagnostics
template<typename T>
concept C = (f(T()), true);
template<typename T>
constexpr bool foo() { return false; }
template<typename T>
requires (f(T()), true)
constexpr bool foo() requires (f(T()), true) { return true; }
namespace a {
struct A {};
void f(A a);
}
static_assert(C<a::A>);
static_assert(foo<a::A>());
namespace a {
// This makes calls to f ambiguous, but the second check will still succeed
// because the constraint satisfaction results are cached.
void f(A a, int = 2);
}
#ifdef NO_CACHE
static_assert(!C<a::A>);
static_assert(!foo<a::A>());
#else
static_assert(C<a::A>);
static_assert(foo<a::A>());
#endif