warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes --> $DIR/hir-const-check.rs:3:30 | LL | #![feature(const_trait_impl, effects)] | ^^^^^^^ | = note: see issue #102090 for more information = note: `#[warn(incomplete_features)]` on by default error[E0658]: `?` is not allowed in a `const fn` --> $DIR/hir-const-check.rs:12:9 | 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to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error: using `#![feature(effects)]` without enabling next trait solver globally | = note: the next trait solver must be enabled globally for the effects feature to work correctly = help: use `-Znext-solver` to enable error: aborting due to 2 previous errors; 1 warning emitted For more information about this error, try `rustc --explain E0658`.