1 // RUN: %clang_cc1 -std=c++11 %s -verify
2 
3 // expected-no-diagnostics
4 
5 namespace PR15757 {
6   struct S {
7   };
8 
9   template<typename X, typename Y> struct T {
TPR15757::T10     template<typename A> T(X x, A &&a) {}
11 
TPR15757::T12     template<typename A> explicit T(A &&a)
13         noexcept(noexcept(T(X(), static_cast<A &&>(a))))
14       : T(X(), static_cast<A &&>(a)) {}
15   };
16 
17   template<typename X, typename Y> struct U : T<X, Y> {
18     using T<X, Y>::T;
19   };
20 
foo(char ch)21   U<S, char> foo(char ch) { return U<S, char>(ch); }
22 
main()23   int main() {
24     U<S, int> a(42);
25     U<S, char> b('4');
26     return 0;
27   }
28 }
29 
30 namespace WrongIdent {
31   struct A {};
32   struct B : A {};
33   struct C : B {
34     using B::A;
35   };
36 }
37 
38 namespace DefaultCtorConflict {
39   struct A { A(int = 0); };
40   struct B : A {
41     using A::A;
42   } b; // ok, not ambiguous, inherited constructor suppresses implicit default constructor
43   struct C {
44     B b;
45   } c;
46 }
47 
48 namespace InvalidConstruction {
49   struct A { A(int); };
50   struct B { B() = delete; };
51   struct C : A, B { using A::A; };
52   // Initialization here is performed as if by a defaulted default constructor,
53   // which would be ill-formed (in the immediate context) in this case because
54   // it would be defined as deleted.
55   template<typename T> void f(decltype(T(0))*);
56   template<typename T> int &f(...);
57   int &r = f<C>(0);
58 }
59