Auto merge of #7263 - Jarcho:redundant_closure_macro, r=llogiq

Fix `redundant_closure` for `vec![]` macro in a closure with arguments

fixes: #7224
changelog: Fix `redundant_closure` for `vec![]` macro in a closure with arguments

clippy_lints/src/eta_reduction.rs

@@ -92,17 +92,19 @@ fn check_closure(cx: &LateContext<'_>, expr: &Expr<'_>) {
  let ex = &body.value;
 
  if ex.span.ctxt() != expr.span.ctxt() {
- if let Some(VecArgs::Vec(&[])) = higher::vec_macro(cx, ex) {
- // replace `|| vec![]` with `Vec::new`
- span_lint_and_sugg(
- cx,
- REDUNDANT_CLOSURE,
- expr.span,
- "redundant closure",
- "replace the closure with `Vec::new`",
- "std::vec::Vec::new".into(),
- Applicability::MachineApplicable,
- );
+ if decl.inputs.is_empty() {
+ if let Some(VecArgs::Vec(&[])) = higher::vec_macro(cx, ex) {
+ // replace `|| vec![]` with `Vec::new`
+ span_lint_and_sugg(
+ cx,
+ REDUNDANT_CLOSURE,
+ expr.span,
+ "redundant closure",
+ "replace the closure with `Vec::new`",
+ "std::vec::Vec::new".into(),
+ Applicability::MachineApplicable,
+ );
+ }
  }
  // skip `foo(|| macro!())`
  return;

tests/ui/eta.fixed

@@ -48,6 +48,9 @@ fn main() {
  // See #515
  let a: Option<Box<dyn (::std::ops::Deref<Target = [i32]>)>> =
  Some(vec![1i32, 2]).map(|v| -> Box<dyn (::std::ops::Deref<Target = [i32]>)> { Box::new(v) });
+
+ // issue #7224
+ let _: Option<Vec<u32>> = Some(0).map(|_| vec![]);
 }
 
 trait TestTrait {

tests/ui/eta.rs

@@ -48,6 +48,9 @@ fn main() {
  // See #515
  let a: Option<Box<dyn (::std::ops::Deref<Target = [i32]>)>> =
  Some(vec![1i32, 2]).map(|v| -> Box<dyn (::std::ops::Deref<Target = [i32]>)> { Box::new(v) });
+
+ // issue #7224
+ let _: Option<Vec<u32>> = Some(0).map(|_| vec![]);
 }
 
 trait TestTrait {

tests/ui/eta.stderr

@@ -33,51 +33,51 @@ LL | let e = Some(1u8).map(|a| generic(a));
  | ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `generic`
 
 error: redundant closure
- --> $DIR/eta.rs:89:51
+ --> $DIR/eta.rs:92:51
  |
 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:91:51
+ --> $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:94:42
+ --> $DIR/eta.rs:97:42
  |
 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:99:29
+ --> $DIR/eta.rs:102:29
  |
 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:101:27
+ --> $DIR/eta.rs:104:27
  |
 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:104:65
+ --> $DIR/eta.rs:107:65
  |
 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:187:27
+ --> $DIR/eta.rs:190:27
  |
 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:192:27
+ --> $DIR/eta.rs:195:27
  |
 LL | let a = Some(1u8).map(|a| closure(a));
  | ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `closure`