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[redundant_closure]: special case inclusive ranges #10905

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Merged
merged 2 commits into from
Jun 8, 2023
Merged

[redundant_closure]: special case inclusive ranges #10905

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2c7cf2c
handle RangeInclusive function desugar
y21 Jun 7, 2023
9ff34ac
actually don't lint for inclusive range
y21 Jun 7, 2023
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8 changes: 8 additions & 0 deletions clippy_lints/src/eta_reduction.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -120,6 +120,13 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
if !is_type_diagnostic_item(cx, callee_ty_unadjusted, sym::Arc);
if !is_type_diagnostic_item(cx, callee_ty_unadjusted, sym::Rc);
if let ty::Closure(_, substs) = *closure_ty.kind();
// Don't lint if this is an inclusive range expression.
// They desugar to a call to `RangeInclusiveNew` which would have odd suggestions. (#10684)
if !matches!(higher::Range::hir(body.value), Some(higher::Range {
start: Some(_),
end: Some(_),
limits: rustc_ast::RangeLimits::Closed
}));
then {
span_lint_and_then(cx, REDUNDANT_CLOSURE, expr.span, "redundant closure", |diag| {
if let Some(mut snippet) = snippet_opt(cx, callee.span) {
Expand All @@ -136,6 +143,7 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
// Mutable closure is used after current expr; we cannot consume it.
snippet = format!("&mut {snippet}");
}

diag.span_suggestion(
expr.span,
"replace the closure with the function itself",
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6 changes: 6 additions & 0 deletions tests/ui/eta.fixed
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Expand Up @@ -46,6 +46,12 @@ fn main() {

// issue #7224
let _: Option<Vec<u32>> = Some(0).map(|_| vec![]);

// issue #10684
fn test<T>(x: impl Fn(usize, usize) -> T) -> T {
x(1, 2)
}
test(|start, end| start..=end);
}

trait TestTrait {
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6 changes: 6 additions & 0 deletions tests/ui/eta.rs
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Expand Up @@ -46,6 +46,12 @@ fn main() {

// issue #7224
let _: Option<Vec<u32>> = Some(0).map(|_| vec![]);

// issue #10684
fn test<T>(x: impl Fn(usize, usize) -> T) -> T {
x(1, 2)
}
test(|start, end| start..=end);
}

trait TestTrait {
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42 changes: 21 additions & 21 deletions tests/ui/eta.stderr
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Expand Up @@ -31,129 +31,129 @@ LL | let e = Some(1u8).map(|a| generic(a));
| ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `generic`

error: redundant closure
--> $DIR/eta.rs:87:51
--> $DIR/eta.rs:93:51
|
LL | let e = Some(TestStruct { some_ref: &i }).map(|a| a.foo());
| ^^^^^^^^^^^ help: replace the closure with the method itself: `TestStruct::foo`
|
= note: `-D clippy::redundant-closure-for-method-calls` implied by `-D warnings`

error: redundant closure
--> $DIR/eta.rs:88:51
--> $DIR/eta.rs:94:51
|
LL | let e = Some(TestStruct { some_ref: &i }).map(|a| a.trait_foo());
| ^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `TestTrait::trait_foo`

error: redundant closure
--> $DIR/eta.rs:90:42
--> $DIR/eta.rs:96:42
|
LL | let e = Some(&mut vec![1, 2, 3]).map(|v| v.clear());
| ^^^^^^^^^^^^^ help: replace the closure with the method itself: `std::vec::Vec::clear`

error: redundant closure
--> $DIR/eta.rs:94:29
--> $DIR/eta.rs:100:29
|
LL | let e = Some("str").map(|s| s.to_string());
| ^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `std::string::ToString::to_string`

error: redundant closure
--> $DIR/eta.rs:95:27
--> $DIR/eta.rs:101:27
|
LL | let e = Some('a').map(|s| s.to_uppercase());
| ^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `char::to_uppercase`

error: redundant closure
--> $DIR/eta.rs:97:65
--> $DIR/eta.rs:103:65
|
LL | let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(|c| c.to_ascii_uppercase()).collect();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `char::to_ascii_uppercase`

error: redundant closure
--> $DIR/eta.rs:160:22
--> $DIR/eta.rs:166:22
|
LL | requires_fn_once(|| x());
| ^^^^^^ help: replace the closure with the function itself: `x`

error: redundant closure
--> $DIR/eta.rs:167:27
--> $DIR/eta.rs:173:27
|
LL | let a = Some(1u8).map(|a| foo_ptr(a));
| ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `foo_ptr`

error: redundant closure
--> $DIR/eta.rs:172:27
--> $DIR/eta.rs:178:27
|
LL | let a = Some(1u8).map(|a| closure(a));
| ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `closure`

error: redundant closure
--> $DIR/eta.rs:204:28
--> $DIR/eta.rs:210:28
|
LL | x.into_iter().for_each(|x| add_to_res(x));
| ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut add_to_res`

error: redundant closure
--> $DIR/eta.rs:205:28
--> $DIR/eta.rs:211:28
|
LL | y.into_iter().for_each(|x| add_to_res(x));
| ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut add_to_res`

error: redundant closure
--> $DIR/eta.rs:206:28
--> $DIR/eta.rs:212:28
|
LL | z.into_iter().for_each(|x| add_to_res(x));
| ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `add_to_res`

error: redundant closure
--> $DIR/eta.rs:213:21
--> $DIR/eta.rs:219:21
|
LL | Some(1).map(|n| closure(n));
| ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut closure`

error: redundant closure
--> $DIR/eta.rs:217:21
--> $DIR/eta.rs:223:21
|
LL | Some(1).map(|n| in_loop(n));
| ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `in_loop`

error: redundant closure
--> $DIR/eta.rs:310:18
--> $DIR/eta.rs:316:18
|
LL | takes_fn_mut(|| f());
| ^^^^^^ help: replace the closure with the function itself: `&mut f`

error: redundant closure
--> $DIR/eta.rs:313:19
--> $DIR/eta.rs:319:19
|
LL | takes_fn_once(|| f());
| ^^^^^^ help: replace the closure with the function itself: `&mut f`

error: redundant closure
--> $DIR/eta.rs:317:26
--> $DIR/eta.rs:323:26
|
LL | move || takes_fn_mut(|| f_used_once())
| ^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut f_used_once`

error: redundant closure
--> $DIR/eta.rs:329:19
--> $DIR/eta.rs:335:19
|
LL | array_opt.map(|a| a.as_slice());
| ^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<[u8; 3]>::as_slice`

error: redundant closure
--> $DIR/eta.rs:332:19
--> $DIR/eta.rs:338:19
|
LL | slice_opt.map(|s| s.len());
| ^^^^^^^^^^^ help: replace the closure with the method itself: `<[u8]>::len`

error: redundant closure
--> $DIR/eta.rs:335:17
--> $DIR/eta.rs:341:17
|
LL | ptr_opt.map(|p| p.is_null());
| ^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<*const usize>::is_null`

error: redundant closure
--> $DIR/eta.rs:339:17
--> $DIR/eta.rs:345:17
|
LL | dyn_opt.map(|d| d.method_on_dyn());
| ^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<dyn TestTrait>::method_on_dyn`
Expand Down