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