error[E0621]: explicit lifetime required in the type of `x` --> $DIR/generator-region-requirements.rs:16:51 | LL | fn dangle(x: &mut i32) -> &'static mut i32 { | -------- help: add explicit lifetime `'static` to the type of `x`: `&'static mut i32` ... LL | GeneratorState::Complete(c) => return c, | ^ lifetime `'static` required error: aborting due to previous error For more information about this error, try `rustc --explain E0621`.