error[E0658]: `?` is not allowed in a `const fn` --> $DIR/const-try-feature-gate.rs:4:5 | LL | Some(())?; | ^^^^^^^^^ | = note: see issue #74935 for more information = help: add `#![feature(const_try)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0658`.