Handle false positive with map_clone lint

clippy_lints/src/methods/map_clone.rs

@@ -86,8 +86,11 @@ pub(super) fn check(cx: &LateContext<'_>, e: &hir::Expr<'_>, recv: &hir::Expr<'_
  }
  }
  },
- hir::ExprKind::Call(call, [_]) => {
- if let hir::ExprKind::Path(qpath) = call.kind {
+ hir::ExprKind::Call(call, args) => {
+ if let hir::ExprKind::Path(qpath) = call.kind
+ && let [arg] = args
+ && ident_eq(name, arg)
+ {
  handle_path(cx, call, &qpath, e, recv);
  }
  },
@@ -118,7 +121,9 @@ fn handle_path(
  if let ty::Adt(_, args) = cx.typeck_results().expr_ty(recv).kind()
  && let args = args.as_slice()
  && let Some(ty) = args.iter().find_map(|generic_arg| generic_arg.as_type())
- && ty.is_ref()
+ && let ty::Ref(_, ty, Mutability::Not) = ty.kind()
+ && let ty::FnDef(_, lst) = cx.typeck_results().expr_ty(arg).kind()
+ && lst.iter().all(|l| l.as_type() == Some(*ty))
  {
  lint_path(cx, e.span, recv.span, is_copy(cx, ty.peel_refs()));
  }

tests/ui/map_clone.fixed

@@ -6,7 +6,8 @@
  clippy::redundant_clone,
  clippy::redundant_closure,
  clippy::useless_asref,
- clippy::useless_vec
+ clippy::useless_vec,
+ clippy::empty_loop
 )]
 
 fn main() {
@@ -117,4 +118,17 @@ fn main() {
  let y = x.as_ref().map(|x| String::clone(x));
  let x: Result<String, ()> = Ok(String::new());
  let y = x.as_ref().map(|x| String::clone(x));
+
+ // Issue #12271
+ {
+ // Don't lint these
+ let x: Option<&u8> = None;
+ let y = x.map(|x| String::clone(loop {}));
+ let x: Option<&u8> = None;
+ let y = x.map(|x| u8::clone(loop {}));
+ let x: Vec<&u8> = vec![];
+ let y = x.into_iter().map(|x| String::clone(loop {}));
+ let x: Vec<&u8> = vec![];
+ let y = x.into_iter().map(|x| u8::clone(loop {}));
+ }
 }

tests/ui/map_clone.rs

@@ -6,7 +6,8 @@
  clippy::redundant_clone,
  clippy::redundant_closure,
  clippy::useless_asref,
- clippy::useless_vec
+ clippy::useless_vec,
+ clippy::empty_loop
 )]
 
 fn main() {
@@ -117,4 +118,17 @@ fn main() {
  let y = x.as_ref().map(|x| String::clone(x));
  let x: Result<String, ()> = Ok(String::new());
  let y = x.as_ref().map(|x| String::clone(x));
+
+ // Issue #12271
+ {
+ // Don't lint these
+ let x: Option<&u8> = None;
+ let y = x.map(|x| String::clone(loop {}));
+ let x: Option<&u8> = None;
+ let y = x.map(|x| u8::clone(loop {}));
+ let x: Vec<&u8> = vec![];
+ let y = x.into_iter().map(|x| String::clone(loop {}));
+ let x: Vec<&u8> = vec![];
+ let y = x.into_iter().map(|x| u8::clone(loop {}));
+ }
 }

tests/ui/map_clone.stderr

@@ -1,5 +1,5 @@
 error: you are using an explicit closure for copying elements
- --> tests/ui/map_clone.rs:13:22
+ --> tests/ui/map_clone.rs:14:22
  |
 LL | let _: Vec<i8> = vec![5_i8; 6].iter().map(|x| *x).collect();
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `vec![5_i8; 6].iter().copied()`
@@ -8,85 +8,85 @@ LL | let _: Vec<i8> = vec![5_i8; 6].iter().map(|x| *x).collect();
  = help: to override `-D warnings` add `#[allow(clippy::map_clone)]`
 
 error: you are using an explicit closure for cloning elements
- --> tests/ui/map_clone.rs:14:26
+ --> tests/ui/map_clone.rs:15:26
  |
 LL | let _: Vec<String> = vec![String::new()].iter().map(|x| x.clone()).collect();
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `vec![String::new()].iter().cloned()`
 
 error: you are using an explicit closure for copying elements
- --> tests/ui/map_clone.rs:15:23
+ --> tests/ui/map_clone.rs:16:23
  |
 LL | let _: Vec<u32> = vec![42, 43].iter().map(|&x| x).collect();
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `vec![42, 43].iter().copied()`
 
 error: you are using an explicit closure for copying elements
- --> tests/ui/map_clone.rs:17:26
+ --> tests/ui/map_clone.rs:18:26
  |
 LL | let _: Option<u64> = Some(&16).map(|b| *b);
  | ^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `Some(&16).copied()`
 
 error: you are using an explicit closure for copying elements
- --> tests/ui/map_clone.rs:18:25
+ --> tests/ui/map_clone.rs:19:25
  |
 LL | let _: Option<u8> = Some(&1).map(|x| x.clone());
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `Some(&1).copied()`
 
 error: you are needlessly cloning iterator elements
- --> tests/ui/map_clone.rs:29:29
+ --> tests/ui/map_clone.rs:30:29
  |
 LL | let _ = std::env::args().map(|v| v.clone());
  | ^^^^^^^^^^^^^^^^^^^ help: remove the `map` call
 
 error: you are explicitly cloning with `.map()`
- --> tests/ui/map_clone.rs:68:13
+ --> tests/ui/map_clone.rs:69:13
  |
 LL | let y = x.map(|x| String::clone(x));
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
- --> tests/ui/map_clone.rs:70:13
+ --> tests/ui/map_clone.rs:71:13
  |
 LL | let y = x.map(Clone::clone);
  | ^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
- --> tests/ui/map_clone.rs:73:13
+ --> tests/ui/map_clone.rs:74:13
  |
 LL | let y = x.map(String::clone);
  | ^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
- --> tests/ui/map_clone.rs:79:13
+ --> tests/ui/map_clone.rs:80:13
  |
 LL | let y = x.map(|x| u32::clone(x));
  | ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `x.copied()`
 
 error: you are explicitly cloning with `.map()`
- --> tests/ui/map_clone.rs:82:13
+ --> tests/ui/map_clone.rs:83:13
  |
 LL | let y = x.map(|x| Clone::clone(x));
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `x.copied()`
 
 error: you are explicitly cloning with `.map()`
- --> tests/ui/map_clone.rs:94:13
+ --> tests/ui/map_clone.rs:95:13
  |
 LL | let y = x.map(|x| String::clone(x));
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
- --> tests/ui/map_clone.rs:97:13
+ --> tests/ui/map_clone.rs:98:13
  |
 LL | let y = x.map(|x| Clone::clone(x));
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
- --> tests/ui/map_clone.rs:103:13
+ --> tests/ui/map_clone.rs:104:13
  |
 LL | let y = x.map(|x| u32::clone(x));
  | ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `x.copied()`
 
 error: you are explicitly cloning with `.map()`
- --> tests/ui/map_clone.rs:106:13
+ --> tests/ui/map_clone.rs:107:13
  |
 LL | let y = x.map(|x| Clone::clone(x));
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `x.copied()`