error[E0054]: cannot cast `i32` as `bool` --> $DIR/cast-rfc0401-2.rs:6:13 | LL | let _ = 3 as bool; | ^^^^^^^^^ | help: compare with zero instead | LL | let _ = 3 != 0; | ~~~~ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0054`.