[Bug c++/70637] Ambiguity error invoking a constructor with double brace initialization

[arthur.j.odwyer at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70637

Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |arthur.j.odwyer at gmail dot com

--- Comment #1 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> ---
Confirmed. I ran into the same issue with a unit test that was trying to test
whether a given constructor was `explicit`.

====
// https://godbolt.org/z/STvgby
#include <initializer_list>

struct S {
    explicit S();
};
struct T {
    T();
};

void foo(S) {}
void foo(T) {}

void bar()
{
    foo({});
}
====

GCC says:
<source>: In function 'void bar()':
<source>:16:11: error: call of overloaded 'foo(<brace-enclosed initializer
list>)' is ambiguous
   16 |     foo({});
      |           ^
<source>:11:6: note: candidate: 'void foo(S)'
   11 | void foo(S) {}
      |      ^~~
<source>:12:6: note: candidate: 'void foo(T)'
   12 | void foo(T) {}
      |      ^~~