c6007fdc70
Constify ?-operator for Result and Option Try to make `?`-operator usable in `const fn` with `Result` and `Option`, see #74935 . Note that the try-operator itself was constified in #87237. TODO * [x] Add tests for const T -> T conversions * [x] cleanup commits * [x] Remove `#![allow(incomplete_features)]` * [?] Await decision in #86808 - I'm not sure * [x] Await support for parsing `~const` in bootstrapping compiler * [x] Tracking issue(s)? - #88674