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

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