| // RUN: %clang_cc1 -std=c2x -fsyntax-only -verify -Wno-unused %s |
| // RUN: %clang_cc1 -fsyntax-only -verify -Wno-unused -x c++ -std=c++17 %s |
| |
| // Test that the semantic behavior of the extension allowing the user to pass a |
| // type as the first argument to _Generic. |
| |
| // Test that we match on basic types. |
| static_assert(_Generic(int, int : 1, default : 0) == 1); |
| static_assert(_Generic(_BitInt(12), int : 1, _BitInt(10) : 2, _BitInt(12) : 3) == 3); |
| |
| // Test that we correctly fall back to the default association appropriately. |
| static_assert(_Generic(int, long : 1, default : 0) == 0); |
| |
| // Ensure we correctly match constant arrays by their extent. |
| static_assert(_Generic(int[12], int[0] : 0, int * : 0, int[12] : 1, default : 0) == 1); |
| |
| // Ensure we correctly match function types by their signature. |
| static_assert(_Generic(int(int), void(void) : 0, int(void) : 0, void(int) : 0, int(int) : 1, default : 0) == 1); |
| |
| // Test that we still diagnose when no associations match and that the |
| // diagnostic includes qualifiers. |
| static_assert(_Generic(const int, long : 1)); // expected-error {{controlling expression type 'const int' not compatible with any generic association type}} |
| |
| // Test that qualifiers work as expected and do not issue a diagnostic when |
| // using the type form. |
| static_assert(_Generic(const int, int : 0, const int : 1) == 1); |
| static_assert(_Generic(int volatile _Atomic const, int : 0, const int : 0, volatile int : 0, _Atomic int : 0, _Atomic const volatile int : 1) == 1); |
| |
| // Test that inferred qualifiers also work as expected. |
| const int ci = 0; |
| static_assert(_Generic(__typeof__(ci), int : 0, const int : 1) == 1); |
| // And that the expression form still complains about qualified associations |
| // and matches the correct association. |
| static_assert(_Generic(ci, int : 1, const int : 0) == 1); // expected-warning {{due to lvalue conversion of the controlling expression, association of type 'const int' will never be selected because it is qualified}} |
| |
| // The type operand form of _Generic allows incomplete and non-object types, |
| // but the expression operand form still rejects them. |
| static_assert(_Generic(struct incomplete, struct incomplete : 1, default : 0) == 1); |
| static_assert(_Generic(struct another_incomplete, struct incomplete : 1, default : 0) == 0); |
| static_assert(_Generic(1, struct also_incomplete : 1, default : 0) == 0); // expected-error {{type 'struct also_incomplete' in generic association incomplete}} |
| |
| void foo(int); |
| static_assert(_Generic(__typeof__(foo), void(int) : 1, default : 0) == 1); |
| static_assert(_Generic(foo, void(int) : 1, default : 0) == 0); // expected-error {{type 'void (int)' in generic association not an object type}} |
| |
| // Ensure we still get a diagnostic for duplicated associations for the type |
| // form, even when using qualified type, and that the diagnostic includes |
| // qualifiers. |
| static_assert(_Generic(const int, |
| const int : 1, // expected-note {{compatible type 'const int' specified here}} |
| int : 2, |
| const int : 3 // expected-error {{type 'const int' in generic association compatible with previously specified type 'const int'}} |
| ) == 1); |
| |
| // Verify that we are matching using the canonical type of the type operand... |
| typedef int Int; |
| typedef const Int CInt; |
| typedef CInt OtherCInt; |
| static_assert(_Generic(volatile CInt, const volatile int : 1, default : 0) == 1); |
| static_assert(_Generic(const int, CInt : 1, default : 0) == 1); |
| |
| // ...and that duplicate associations are doing so as well. |
| static_assert(_Generic(const int, |
| CInt : 1, // expected-note {{compatible type 'CInt' (aka 'const int') specified here}} |
| const volatile int : 2, |
| OtherCInt : 3 // expected-error {{type 'OtherCInt' (aka 'const int') in generic association compatible with previously specified type 'CInt' (aka 'const int')}} |
| ) == 1); |
| |
| // Also test that duplicate array or function types are caught. |
| static_assert(_Generic(const int, |
| int[12] : 0, // expected-note {{compatible type 'int[12]' specified here}} |
| int[12] : 0, // expected-error {{type 'int[12]' in generic association compatible with previously specified type 'int[12]'}} |
| int(int) : 0, // expected-note {{compatible type 'int (int)' specified here}} |
| int(int) : 0, // expected-error {{type 'int (int)' in generic association compatible with previously specified type 'int (int)'}} |
| default : 1 |
| ) == 1); |
| |
| |
| // Tests that only make sense for C++: |
| #ifdef __cplusplus |
| // Ensure that _Generic works within a template argument list. |
| template <typename Ty, int N = _Generic(Ty, int : 0, default : 1)> |
| constexpr Ty bar() { return N; } |
| |
| static_assert(bar<int>() == 0); |
| static_assert(bar<float>() == 1); |
| |
| // Or that it can be used as a non-type template argument. |
| static_assert(bar<int, _Generic(int, int : 1, default : 0)>() == 1); |
| |
| // Ensure that a dependent type works as expected. |
| template <typename Ty> |
| struct Dependent { |
| // If we checked the type early, this would fail to compile without any |
| // instantiation. Instead, it only fails with the bad instantiation. |
| static_assert(_Generic(Ty, int : 1)); // expected-error {{controlling expression type 'double' not compatible with any generic association type}} \ |
| expected-note@#BadInstantiation {{in instantiation of template class 'Dependent<double>' requested here}} |
| }; |
| |
| template struct Dependent<int>; // Good instantiation |
| template struct Dependent<double>; // #BadInstantiation |
| |
| // Another template instantiation test, this time for a variable template with |
| // a type-dependent initializer. |
| template <typename Ty> |
| constexpr auto Val = _Generic(Ty, Ty : Ty{}); |
| |
| static_assert(Val<int> == 0); |
| static_assert(__is_same(decltype(Val<Dependent<int>>), const Dependent<int>)); |
| |
| // Ensure that pack types also work as expected. |
| template <unsigned Arg, unsigned... Args> struct Or { |
| enum { result = Arg | Or<Args...>::result }; |
| }; |
| |
| template <unsigned Arg> struct Or<Arg> { |
| enum { result = Arg }; |
| }; |
| |
| template <class... Args> struct TypeMask { |
| enum { |
| result = Or<_Generic(Args, int: 1, long: 2, short: 4, float: 8)...>::result |
| }; |
| }; |
| |
| static_assert(TypeMask<int, long, short>::result == 7, "fail"); |
| static_assert(TypeMask<float, short>::result == 12, "fail"); |
| static_assert(TypeMask<int, float, float>::result == 9, "fail"); |
| |
| template <typename... T> |
| void f() { |
| // Because _Generic only accepts a single type argument, it does not make |
| // sense for it to accept a pack, so a pack is rejected while parsing. |
| _Generic(T..., int : 1); // expected-error {{expected ','}} |
| } |
| #endif // __cplusplus |