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#![warn(clippy::result_map_unit_fn)]
#![feature(never_type)]
#![allow(unused, clippy::unnecessary_map_on_constructor)]
//@no-rustfix
struct HasResult {
field: Result<usize, usize>,
}
fn do_nothing<T>(_: T) {}
fn diverge<T>(_: T) -> ! {
panic!()
}
fn plus_one(value: usize) -> usize {
value + 1
}
#[rustfmt::skip]
fn result_map_unit_fn() {
let x = HasResult { field: Ok(10) };
x.field.map(|value| { do_nothing(value); do_nothing(value) });
//~^ ERROR: called `map(f)` on an `Result` value where `f` is a closure that returns t
//~| NOTE: `-D clippy::result-map-unit-fn` implied by `-D warnings`
x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
//~^ ERROR: called `map(f)` on an `Result` value where `f` is a closure that returns t
// Suggestion for the let block should be `{ ... }` as it's too difficult to build a
// proper suggestion for these cases
x.field.map(|value| {
//~^ ERROR: called `map(f)` on an `Result` value where `f` is a closure that returns t
do_nothing(value);
do_nothing(value)
});
x.field.map(|value| { do_nothing(value); do_nothing(value); });
//~^ ERROR: called `map(f)` on an `Result` value where `f` is a closure that returns t
// The following should suggest `if let Ok(_X) ...` as it's difficult to generate a proper let variable name for them
let res: Result<!, usize> = Ok(42).map(diverge);
"12".parse::<i32>().map(diverge);
//~^ ERROR: called `map(f)` on an `Result` value where `f` is a function that returns
let res: Result<(), usize> = Ok(plus_one(1)).map(do_nothing);
// Should suggest `if let Ok(_y) ...` to not override the existing foo variable
let y: Result<usize, usize> = Ok(42);
y.map(do_nothing);
//~^ ERROR: called `map(f)` on an `Result` value where `f` is a function that returns
}
fn main() {}
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