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// RUN: %clang_cc1 -std=c++20 -verify %s
template <class T>
requires(sizeof(T) > 2) || T::value // #FOO_REQ
void Foo(T){}; // #FOO
template <class T>
void TrailingReturn(T) // #TRAILING
requires(sizeof(T) > 2) || // #TRAILING_REQ
T::value // #TRAILING_REQ_VAL
{};
template <bool B>
struct HasValue {
static constexpr bool value = B;
};
static_assert(sizeof(HasValue<true>) <= 2);
template <bool B>
struct HasValueLarge {
static constexpr bool value = B;
int I;
};
static_assert(sizeof(HasValueLarge<true>) > 2);
void usage() {
// Passes the 1st check, short-circuit so the 2nd ::value is not evaluated.
Foo(1.0);
TrailingReturn(1.0);
// Fails the 1st check, but has a ::value, so the check happens correctly.
Foo(HasValue<true>{});
TrailingReturn(HasValue<true>{});
// Passes the 1st check, but would have passed the 2nd one.
Foo(HasValueLarge<true>{});
TrailingReturn(HasValueLarge<true>{});
// Fails the 1st check, fails 2nd because there is no ::value.
Foo(true);
// expected-error@-1{{no matching function for call to 'Foo'}}
// expected-note@#FOO{{candidate template ignored: constraints not satisfied [with T = bool]}}
// expected-note@#FOO_REQ{{because 'sizeof(_Bool) > 2' (1 > 2) evaluated to false}}
// expected-note@#FOO_REQ{{because substituted constraint expression is ill-formed: type 'bool' cannot be used prior to '::' because it has no members}}
TrailingReturn(true);
// expected-error@-1{{no matching function for call to 'TrailingReturn'}}
// expected-note@#TRAILING{{candidate template ignored: constraints not satisfied [with T = bool]}}
// expected-note@#TRAILING_REQ{{because 'sizeof(_Bool) > 2' (1 > 2) evaluated to false}}
// expected-note@#TRAILING_REQ_VAL{{because substituted constraint expression is ill-formed: type 'bool' cannot be used prior to '::' because it has no members}}
// Fails the 1st check, fails 2nd because ::value is false.
Foo(HasValue<false>{});
// expected-error@-1 {{no matching function for call to 'Foo'}}
// expected-note@#FOO{{candidate template ignored: constraints not satisfied [with T = HasValue<false>]}}
// expected-note@#FOO_REQ{{because 'sizeof(HasValue<false>) > 2' (1 > 2) evaluated to false}}
// expected-note@#FOO_REQ{{and 'HasValue<false>::value' evaluated to false}}
TrailingReturn(HasValue<false>{});
// expected-error@-1 {{no matching function for call to 'TrailingReturn'}}
// expected-note@#TRAILING{{candidate template ignored: constraints not satisfied [with T = HasValue<false>]}}
// expected-note@#TRAILING_REQ{{because 'sizeof(HasValue<false>) > 2' (1 > 2) evaluated to false}}
// expected-note@#TRAILING_REQ_VAL{{and 'HasValue<false>::value' evaluated to false}}
}
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