Tracking issue for feature(repr128); enums with 128-bit discriminants

[Centril]

This issue tracks repr128, i.e. "enums with 128-bit discriminant" as per rust-lang/rfcs#1504.
Originally this was tracked in #35118.

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Nothing has changed re repr128… It is still the case that at least LLVM’s debuginfo API blocks us from implementing it at all. There’s very little incentive to work on it, though, and I’m not planning to do anything in that direction until a very convincing use-case for 128-bit enum discriminants comes up.

- @nagisa

[clarfonthey]

I actually double checked the RFC text and I didn't see mentions of repr(u128) anywhere. Is it still a feature that's desired?

[nagisa]

It’s a generic feature tied to integers in the language. It is not mentioned in the RFC because it would’ve implemented along with the integers themselves lest the roadblocks didn’t show up.