error[E0277]: the trait bound `[closure@$DIR/issue-102985.rs:4:23: 4:25]: ~const Fn<()>` is not satisfied --> $DIR/issue-102985.rs:5:14 | LL | n => n(), | ^^^ expected an `Fn<()>` closure, found `[closure@$DIR/issue-102985.rs:4:23: 4:25]` | = help: the trait `~const Fn<()>` is not implemented for closure `[closure@$DIR/issue-102985.rs:4:23: 4:25]` note: the trait `Fn<()>` is implemented for `[closure@$DIR/issue-102985.rs:4:23: 4:25]`, but that implementation is not `const` --> $DIR/issue-102985.rs:5:14 | LL | n => n(), | ^^^ = note: wrap the `[closure@$DIR/issue-102985.rs:4:23: 4:25]` in a closure with no arguments: `|| { /* code */ }` error[E0277]: the trait bound `[closure@$DIR/issue-102985.rs:4:23: 4:25]: ~const Fn<()>` is not satisfied --> $DIR/issue-102985.rs:5:14 | LL | n => n(), | ^^^ expected an `Fn<()>` closure, found `[closure@$DIR/issue-102985.rs:4:23: 4:25]` | = help: the trait `~const Fn<()>` is not implemented for closure `[closure@$DIR/issue-102985.rs:4:23: 4:25]` note: the trait `Fn<()>` is implemented for `[closure@$DIR/issue-102985.rs:4:23: 4:25]`, but that implementation is not `const` --> $DIR/issue-102985.rs:5:14 | LL | n => n(), | ^^^ = note: wrap the `[closure@$DIR/issue-102985.rs:4:23: 4:25]` in a closure with no arguments: `|| { /* code */ }` error[E0015]: cannot call non-const closure in constants --> $DIR/issue-102985.rs:5:14 | LL | n => n(), | ^^^ | = note: closures need an RFC before allowed to be called in constants = note: calls in constants are limited to constant functions, tuple structs and tuple variants error: aborting due to 3 previous errors Some errors have detailed explanations: E0015, E0277. For more information about an error, try `rustc --explain E0015`.