cxx-explicit-specifier.cpp
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// RUN: %clang_cc1 -std=c++2a -emit-pch %s -o %t-cxx2a
// RUN: %clang_cc1 -std=c++2a -DUSE_PCH -include-pch %t-cxx2a %s -ast-print -verify | FileCheck %s
#ifndef USE_PCH
namespace inheriting_constructor {
struct S {};
template<typename X, typename Y> struct T {
template<typename A>
explicit((Y{}, true)) T(A &&a) {}
};
template<typename X, typename Y> struct U : T<X, Y> {
using T<X, Y>::T;
};
U<S, char> foo(char ch) {
return U<S, char>(ch);
}
}
#else
namespace inheriting_constructor {
U<S, char> a = foo('0');
}
//CHECK: explicit((char{} , true))
#endif
namespace basic {
#ifndef USE_PCH
struct B {};
struct A {
explicit A(int);
explicit(false) operator bool();
explicit(true) operator B();
};
#else
//expected-note@-6+ {{candidate constructor}}
//expected-note@-9+ {{candidate constructor}}
//expected-note-re@-7+ {{explicit constructor is not a candidate{{$}}}}
//expected-note@-7+ {{candidate function}}
//expected-note@-7+ {{explicit conversion function is not a candidate (explicit specifier evaluates to true)}}
//CHECK: explicit{{ +}}A(
//CHECK-NEXT: explicit(false){{ +}}operator
//CHECK-NEXT: explicit(true){{ +}}operator
A a = 0; //expected-error {{no viable conversion}}
A a1(0);
bool b = a1;
B b1 = a1; //expected-error {{no viable conversion}}
#endif
}
namespace templ {
#ifndef USE_PCH
template<bool b>
struct B {
static constexpr bool value = b;
};
template<bool b>
struct A {
explicit(b) A(B<b>) {}
template<typename T>
explicit(b ^ T::value) operator T();
};
B<true> b_true;
B<false> b_false;
#else
//expected-note@-8 {{candidate template ignored}}
//expected-note@-8 {{explicit constructor declared here}}
//expected-note@-15+ {{candidate constructor}}
//expected-note@-8+ {{explicit conversion function is not a candidate (explicit specifier}}
//expected-note@-11 {{explicit constructor is not a candidate (explicit specifier}}
//CHECK: explicit(b){{ +}}A
//CHECK: explicit(b{{ +}}^{{ +}}T::value){{ +}}operator
A a = { b_true }; //expected-error {{class template argument deduction}}
A a0 = b_true; //expected-error {{no viable constructor or deduction guide}}
A a_true(b_true);
A a_false = b_false;
B<true> b = a_true;
B<true> b1 = a_false; //expected-error {{no viable conversion}}
B<false> b2(a_true);
#endif
}
namespace guide {
#ifndef USE_PCH
template<typename T>
struct A {
A(T);
};
template<typename T>
explicit(true) A(T) -> A<T>;
explicit(false) A(int) -> A<int>;
#else
//expected-note@-5 {{explicit deduction guide}}
//CHECK: explicit(true){{ +}}A(
//CHECK: explicit(false){{ +}}A(
A a = { 0.0 }; //expected-error {{explicit deduction guide}}
A a1 = { 0 };
#endif
}