[clang] Implement P3074R7 - trivial unions

[cor3ntin]

https://wg21.link/p3074r7

Issues were found in the paper after the meeting so we should punt on that while CWG decides what to do

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: cor3ntin (cor3ntin)

https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2024/p3074r5.html

Issues were found in the paper after the meeting so we should punt on that while CWG decides what to do

[frederick-vs-ja]

Was it intended to record R5 but not R7 (https://wg21.link/p3074r7) here?

[wusatosi]

Hey @cor3ntin I think waiting-for-wg21 can be removed as it was voted in in the plenary.

See: cplusplus/draft#7680

[cor3ntin]

see
https://cplusplus.github.io/CWG/issues/2999.html

The committee was redesigning the whole feature right after the meeting, it seems prudent to wait.

[wusatosi]

see https://cplusplus.github.io/CWG/issues/2999.html

The committee was redesigning the whole feature right after the meeting, it seems prudent to wait.

Thanks for the info! I didn't know about this, I am surprised they're designing this so late in 26's pipeline, is any form of trivial union going to be in 26?