error[E0277]: the trait bound `Bar: Copy` is not satisfied --> $DIR/fn-call-in-non-const.rs:14:32 | LL | let _: [Option; 2] = [no_copy(); 2]; | ^^^^^^^^^ the trait `Copy` is not implemented for `Bar` | = note: required for `Option` to implement `Copy` = note: the `Copy` trait is required because this value will be copied for each element of the array = help: consider creating a new `const` item and initializing it with the result of the function call to be used in the repeat position, like `const VAL: Type = const_fn();` and `let x = [VAL; 42];` = help: create an inline `const` block, see RFC #2920 for more information help: consider annotating `Bar` with `#[derive(Copy)]` | LL | #[derive(Copy)] | error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.