https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113300
Bug ID: 113300
Summary: GCC rejects valid program involving explicit and non
explicit default constructors
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jlame646 at gmail dot com
Target Milestone: ---
The following valid program is rejected by gcc and clang but accepted by msvc.
https://godbolt.org/z/Y3x8nP11M
```
struct A
{
explicit A(int = 10);
A()= default;
};
A a = {}; //msvc ok but gcc and clang fails here
```
GCC says:
```
<source>:8:8: error: conversion from '<brace-enclosed initializer list>' to 'A'
is ambiguous
8 | A a = {}; //msvc ok but gcc and clang fails here
| ^
<source>:5:3: note: candidate: 'constexpr A::A()'
5 | A()= default;
| ^
<source>:4:12: note: candidate: 'A::A(int)'
4 | explicit A(int = 10);
```
The reason why this is valid is discussed here:
https://stackoverflow.com/questions/77788861/ambiguous-constructor-error-in-gcc-but-not-in-msvc
