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//@require-annotations-for-level: ERROR
#![warn(clippy::map_identity)]
#![allow(clippy::needless_return, clippy::disallowed_names)]
fn main() {
let x: [u16; 3] = [1, 2, 3];
// should lint
let _: Vec<_> = x.iter().map(not_identity).collect();
//~^ map_identity
let _: Vec<_> = x.iter().collect();
//~^ map_identity
//~| map_identity
let _: Option<u8> = Some(3);
//~^ map_identity
let _: Result<i8, f32> = Ok(-3);
// should not lint
let _: Vec<_> = x.iter().map(|x| 2 * x).collect();
let _: Vec<_> = x.iter().map(not_identity).map(|x| return x - 4).collect();
let _: Option<u8> = None.map(|x: u8| x - 1);
let _: Result<i8, f32> = Err(2.3).map(|x: i8| {
return x + 3;
});
let _: Result<u32, u32> = Ok(1);
//~^ map_identity
let _: Result<u32, u32> = Ok(1).map_err(|a: u32| a * 42);
// : u32 guides type inference
let _ = Ok(1).map_err(|a: u32| a);
let _ = Ok(1).map_err(std::convert::identity::<u32>);
}
fn issue7189() {
// should lint
let x = [(1, 2), (3, 4)].iter().copied();
let _ = x.clone();
//~^ map_identity
let _ = x.clone();
let _ = x.clone();
//~^ map_identity
let y = [(1, 2, (3, (4,))), (5, 6, (7, (8,)))].iter().copied();
let _ = y.clone();
//~^ map_identity
// should not lint
let _ = x.clone().map(|(x, y)| (x, y, y));
let _ = x.clone().map(|(x, _y)| (x,));
let _ = x.clone().map(|(x, _)| (x,));
let _ = x.clone().map(|(x, ..)| (x,));
let _ = y.clone().map(|(x, y, (z, _))| (x, y, (z, z)));
let _ = y
.clone()
.map(|(x, y, (z, _)): (i32, i32, (i32, (i32,)))| (x, y, (z, z)));
let _ = y
.clone()
.map(|(x, y, (z, (w,))): (i32, i32, (i32, (i32,)))| (x, y, (z, (w,))));
}
fn not_identity(x: &u16) -> u16 {
*x
}
fn issue11764() {
let x = [(1, 2), (3, 4)];
// don't lint: this is an `Iterator<Item = &(i32, i32)>`
// match ergonomics makes the binding patterns into references
// so that its type changes to `Iterator<Item = (&i32, &i32)>`
let _ = x.iter().map(|(x, y)| (x, y));
let _ = x.iter().map(|x| (x.0,)).map(|(x,)| x);
// no match ergonomics for `(i32, i32)`
let _ = x.iter().copied();
//~^ map_identity
}
fn issue13904() {
// lint, but there's a catch:
// when we remove the `.map()`, `it.next()` would require `it` to be mutable
// therefore, include that in the suggestion as well
let mut it = [1, 2, 3].into_iter();
let _ = it.next();
//~^ map_identity
//~| HELP: remove the call to `map`, and make `it` mutable
// lint
let mut index = [1, 2, 3].into_iter();
let mut subindex = (index.by_ref().take(3), 42);
let _ = subindex.0.next();
//~^ map_identity
//~| HELP: remove the call to `map`, and make `subindex` mutable
// lint
#[allow(unused_mut)]
let mut it = [1, 2, 3].into_iter();
let _ = it.next();
//~^ map_identity
//~| HELP: remove the call to `map`
// lint
let it = [1, 2, 3].into_iter();
let _ = { it }.next();
//~^ map_identity
//~| HELP: remove the call to `map`
}
// same as `issue11764`, but for arrays
fn issue15198() {
let x = [[1, 2], [3, 4]];
// don't lint: `&[i32; 2]` becomes `[&i32; 2]`
let _ = x.iter().map(|[x, y]| [x, y]);
let _ = x.iter().map(|x| [x[0]]).map(|[x]| x);
// no match ergonomics for `[i32, i32]`
let _ = x.iter().copied();
//~^ map_identity
}
mod foo {
#[derive(Clone, Copy)]
pub struct Foo {
pub foo: u8,
pub bar: u8,
}
#[derive(Clone, Copy)]
pub struct Foo2(pub u8, pub u8);
}
use foo::{Foo, Foo2};
struct Bar {
foo: u8,
bar: u8,
}
struct Bar2(u8, u8);
fn structs() {
let x = [Foo { foo: 0, bar: 0 }];
let _ = x.into_iter();
//~^ map_identity
// still lint when different paths are used for the same struct
let _ = x.into_iter();
//~^ map_identity
// don't lint: same fields but different structs
let _ = x.into_iter().map(|Foo { foo, bar }| Bar { foo, bar });
// still lint with redundant field names
#[allow(clippy::redundant_field_names)]
let _ = x.into_iter();
//~^ map_identity
// still lint with field order change
let _ = x.into_iter();
//~^ map_identity
// don't lint: switched field assignment
let _ = x.into_iter().map(|Foo { foo, bar }| Foo { foo: bar, bar: foo });
}
fn tuple_structs() {
let x = [Foo2(0, 0)];
let _ = x.into_iter();
//~^ map_identity
// still lint when different paths are used for the same struct
let _ = x.into_iter();
//~^ map_identity
// don't lint: same fields but different structs
let _ = x.into_iter().map(|Foo2(foo, bar)| Bar2(foo, bar));
// don't lint: switched field assignment
let _ = x.into_iter().map(|Foo2(foo, bar)| Foo2(bar, foo));
}
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