[Bug c++/84849] Ambiguous resolution of braze initializer list to a class with explicit copy/move constructors

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84849

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-03-13
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jose Dapena Paz from comment #0)
> For a template class with explicit copy and move constructors,

Those aren't copy and move constructors.

Reduced:

struct X
{
  X(const char*) { }
};

template <typename T>
class Foo {
 public:
  template <typename... Args>
  explicit Foo(Args&&... args);

  explicit Foo(const T&);
  explicit Foo(T&&) { }

  Foo(const Foo&) = delete;
  Foo& operator=(const Foo&) = delete;

  ~Foo() = default;
};

int main() {
  Foo<X> v({"a"});
}



vs.cc: In function 'int main()':
vs.cc:22:17: error: call of overloaded 'Foo(<brace-enclosed initializer list>)'
is ambiguous
   Foo<X> v({"a"});
                 ^
vs.cc:15:3: note: candidate: 'Foo<T>::Foo(const Foo<T>&) [with T = X]'
<deleted>
   Foo(const Foo&) = delete;
   ^~~
vs.cc:13:12: note: candidate: 'Foo<T>::Foo(T&&) [with T = X]'
   explicit Foo(T&&) { }
            ^~~
vs.cc:12:12: note: candidate: 'Foo<T>::Foo(const T&) [with T = X]'
   explicit Foo(const T&);
            ^~~