lint reborrow in Local

Author: lengyijun

clippy_lints/src/borrow_deref_ref.rs

@@ -68,21 +68,13 @@ impl LateLintPass<'_> for BorrowDerefRef {
                         return;
                     }
                     if matches!(deref_expr.kind, ExprKind::Path(..) | ExprKind::Field(..)) {
-                        if let Some(parent_node) = map.find(parent_hir_id) {
-                            if let rustc_hir::Node::Local(..) = parent_node {
-                                let outer_ty = cx.typeck_results().node_type(parent_hir_id);
-                                if outer_ty == ref_ty {
-                                    return;
-                                }
+                        if let Some(rustc_hir::Node::Expr(parent_expr)) = map.find(parent_hir_id) {
+                            if matches!(parent_expr.kind, ExprKind::AddrOf(_, Mutability::Mut, _)) {
+                                return;
                             }
-                            if let rustc_hir::Node::Expr(parent_expr) = parent_node {
-                                if matches!(parent_expr.kind, ExprKind::AddrOf(_, Mutability::Mut, _)) {
-                                    return;
-                                }
-                                if matches!(parent_expr.kind, ExprKind::Unary(UnOp::Deref, ..)) &&
-                                   !is_lint_allowed(cx, DEREF_ADDROF, parent_expr.hir_id) {
-                                    return;
-                                }
+                            if matches!(parent_expr.kind, ExprKind::Unary(UnOp::Deref, ..)) &&
+                               !is_lint_allowed(cx, DEREF_ADDROF, parent_expr.hir_id) {
+                                return;
                             }
                         }
                     }

tests/ui/borrow_deref_ref.rs

@@ -2,27 +2,22 @@ fn main() {}
 
 mod should_lint {
     fn foo() {
+        let a = &12;
+        let b = &*a;
+
         let s = &String::new();
-        let a: &str = &*s;
+        let x: &str = &*s;
 
-        let a = &12;
-        let b = &mut &*bar(a);
+        let b = &mut &*bar(&12);
     }
 
     fn bar(x: &u32) -> &u32 {
         x
     }
 }
 
-mod should_not_lint1 {
-    fn not_lint_simple_reborrow() {
-        let a = &12;
-        let b = &*a;
-    }
-}
-
 // this mod explains why we should not lint `&mut &* (&T)`
-mod should_not_lint2 {
+mod should_not_lint1 {
     fn foo(x: &mut &u32) {
         *x = &1;
     }
@@ -37,8 +32,8 @@ mod should_not_lint2 {
     }
 }
 
-// similar to should_not_lint2
-mod should_not_lint3 {
+// similar to should_not_lint1
+mod should_not_lint2 {
     struct S<'a> {
         a: &'a u32,
         b: u32,

tests/ui/borrow_deref_ref.stderr

@@ -1,28 +1,36 @@
 error: deref on an immutable reference
-  --> $DIR/borrow_deref_ref.rs:6:23
+  --> $DIR/borrow_deref_ref.rs:6:17
    |
-LL |         let a: &str = &*s;
-   |                       ^^^
+LL |         let b = &*a;
+   |                 ^^^
    |
    = note: `-D clippy::borrow-deref-ref` implied by `-D warnings`
+   = help: consider using `a` if you would like to reborrow
+
+error: deref on an immutable reference
+  --> $DIR/borrow_deref_ref.rs:9:23
+   |
+LL |         let x: &str = &*s;
+   |                       ^^^
+   |
    = help: consider using `&**s` if you would like to deref
    = help: consider using `s` if you would like to reborrow
 
 error: deref on an immutable reference
-  --> $DIR/borrow_deref_ref.rs:9:22
+  --> $DIR/borrow_deref_ref.rs:11:22
    |
-LL |         let b = &mut &*bar(a);
-   |                      ^^^^^^^^
+LL |         let b = &mut &*bar(&12);
+   |                      ^^^^^^^^^^
    |
-   = help: consider using `bar(a)` if you would like to reborrow
+   = help: consider using `bar(&12)` if you would like to reborrow
 
 error: deref on an immutable reference
-  --> $DIR/borrow_deref_ref.rs:59:23
+  --> $DIR/borrow_deref_ref.rs:54:23
    |
 LL |         let addr_y = &&*x as *const _ as usize; // assert ok
    |                       ^^^
    |
    = help: consider using `x` if you would like to reborrow
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors