#![warn(option_map_unit_fn)] #![allow(unused)] fn do_nothing(_: T) {} fn diverge(_: T) -> ! { panic!() } fn plus_one(value: usize) -> usize { value + 1 } struct HasOption { field: Option, } impl HasOption { fn do_option_nothing(self: &Self, value: usize) {} fn do_option_plus_one(self: &Self, value: usize) -> usize { value + 1 } } #[cfg_attr(rustfmt, rustfmt_skip)] fn main() { let x = HasOption { field: Some(10) }; x.field.map(plus_one); let _ : Option<()> = x.field.map(do_nothing); x.field.map(do_nothing); x.field.map(do_nothing); x.field.map(diverge); let captured = 10; if let Some(value) = x.field { do_nothing(value + captured) }; let _ : Option<()> = x.field.map(|value| do_nothing(value + captured)); x.field.map(|value| x.do_option_nothing(value + captured)); x.field.map(|value| { x.do_option_plus_one(value + captured); }); x.field.map(|value| do_nothing(value + captured)); x.field.map(|value| { do_nothing(value + captured) }); x.field.map(|value| { do_nothing(value + captured); }); x.field.map(|value| { { do_nothing(value + captured); } }); x.field.map(|value| diverge(value + captured)); x.field.map(|value| { diverge(value + captured) }); x.field.map(|value| { diverge(value + captured); }); x.field.map(|value| { { diverge(value + captured); } }); x.field.map(|value| plus_one(value + captured)); x.field.map(|value| { plus_one(value + captured) }); x.field.map(|value| { let y = plus_one(value + captured); }); x.field.map(|value| { plus_one(value + captured); }); x.field.map(|value| { { plus_one(value + captured); } }); x.field.map(|ref value| { do_nothing(value + captured) }); x.field.map(|value| { do_nothing(value); do_nothing(value) }); x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) }); // Suggestion for the let block should be `{ ... }` as it's too difficult to build a // proper suggestion for these cases x.field.map(|value| { do_nothing(value); do_nothing(value) }); x.field.map(|value| { do_nothing(value); do_nothing(value); }); }