Fields with the same name across different anonymous structures inside on union

Question

Is it legal to have fields with the same name across different anonymous structures inside one union?

union Foo
{
    struct
    {
        int bar;
    };

    struct
    {
        int bar;
    };
};

MSVC does in fact allow this while GCC doesn't.

@Neil Butterworth It was actually made by an accident as the real example is much bigger and more complex than the one I've provided here — FrozenHeart, Nov 14 '18 at 22:20
Possible duplicate of [Are "anonymous structs" standard? And, really, what \*are\* they?](https://stackoverflow.com/questions/14248044/are-anonymous-structs-standard-and-really-what-are-they) — Swordfish, Nov 14 '18 at 22:24
Possible duplicate of [Anonymous union and struct](https://stackoverflow.com/questions/25542390/anonymous-union-and-struct) — Swordfish, Nov 14 '18 at 22:25
Disable language extensions of `cl` (`/Za`) and get: `error C2467: illegal declaration of anonymous 'struct'` and `error C2658: 'Foo::bar': redefinition in anonymous struct/union`. — Swordfish, Nov 14 '18 at 22:50

score 4 · Accepted Answer · answered Nov 14 '18 at 22:20

4

The code is not valid, simply because C++ has no anonymous structures.

With -pedantic-errors, GCC refuses to compile it with error: ISO C++ prohibits anonymous structs [-Wpedantic].

answered Nov 14 '18 at 22:20

HolyBlackCat

I've just updated my question, please take a look at the new version. – FrozenHeart Nov 14 '18 at 22:29
@FrozenHeart I'd say it warrants a separate question, probably tagged `language-lawyer`. But since both GCC and Clang reject the new snippet as well, I smell MSVC bug. – HolyBlackCat Nov 14 '18 at 22:34

1 Answers1