42 lines
1.9 KiB
C++
42 lines
1.9 KiB
C++
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// RUN: %clang_cc1 -std=c++2a -x c++ -verify %s
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template<typename T>
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constexpr bool is_ptr_v = false;
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template<typename T>
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constexpr bool is_ptr_v<T*> = true;
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template<typename T, typename U>
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constexpr bool is_same_v = false;
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template<typename T>
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constexpr bool is_same_v<T, T> = true;
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template<typename T> requires is_ptr_v<T> // expected-note {{because 'is_ptr_v<int>' evaluated to false}}
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// expected-note@-1{{because 'is_ptr_v<char>' evaluated to false}}
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auto dereference(T t) { // expected-note {{candidate template ignored: constraints not satisfied [with T = int]}}
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// expected-note@-1{{candidate template ignored: constraints not satisfied [with T = char]}}
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return *t;
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}
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static_assert(is_same_v<decltype(dereference<int*>(nullptr)), int>);
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static_assert(is_same_v<decltype(dereference(2)), int>); // expected-error {{no matching function for call to 'dereference'}}
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static_assert(is_same_v<decltype(dereference<char>('a')), char>); // expected-error {{no matching function for call to 'dereference'}}
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template<typename T> requires (T{} + T{}) // expected-note {{because substituted constraint expression is ill-formed: invalid operands to binary expression ('A' and 'A')}}
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auto foo(T t) { // expected-note {{candidate template ignored: constraints not satisfied [with T = A]}}
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return t + t;
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}
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template<typename T> requires (!((T{} - T{}) && (T{} + T{})) || false)
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// expected-note@-1{{because substituted constraint expression is ill-formed: invalid operands to binary expression ('A' and 'A')}}
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// expected-note@-2{{and 'false' evaluated to false}}
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auto bar(T t) { // expected-note {{candidate template ignored: constraints not satisfied [with T = A]}}
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return t + t;
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}
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struct A { };
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static_assert(foo(A{})); // expected-error {{no matching function for call to 'foo'}}
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static_assert(bar(A{})); // expected-error {{no matching function for call to 'bar'}}
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