Auto merge of rust-lang#11376 - Jarcho:issue_11366, r=llogiq

Fix span when linting `explicit_auto_deref` immediately after `needless_borrow`

fixes rust-lang#11366

changelog: `explicit_auto_deref`: Fix span when linting immediately after `needless_borrow`

Author: bors

clippy_lints/src/dereference.rs

@@ -609,12 +609,14 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing<'tcx> {
                             adjusted_ty,
                         },
                     ));
-                } else if stability.is_deref_stable() {
+                } else if stability.is_deref_stable()
+                    && let Some(parent) = get_parent_expr(cx, expr)
+                {
                     self.state = Some((
                         State::ExplicitDeref { mutability: None },
                         StateData {
-                            span: expr.span,
-                            hir_id: expr.hir_id,
+                            span: parent.span,
+                            hir_id: parent.hir_id,
                             adjusted_ty,
                         },
                     ));

tests/ui/explicit_auto_deref.fixed

@@ -205,7 +205,7 @@ fn main() {
         }
     }
 
-    f_str(&&ref_str); // `needless_borrow` will suggest removing both references
+    f_str(&ref_str); // `needless_borrow` will suggest removing both references
     f_str(&ref_str); // `needless_borrow` will suggest removing only one reference
 
     let x = &&40;
@@ -293,4 +293,10 @@ fn main() {
     fn return_dyn_assoc<'a>(x: &'a &'a u32) -> &'a <&'a u32 as WithAssoc>::Assoc {
         *x
     }
+
+    // Issue #11366
+    let _: &mut u32 = match &mut Some(&mut 0u32) {
+        Some(x) => x,
+        None => panic!(),
+    };
 }

tests/ui/explicit_auto_deref.rs

@@ -293,4 +293,10 @@ fn main() {
     fn return_dyn_assoc<'a>(x: &'a &'a u32) -> &'a <&'a u32 as WithAssoc>::Assoc {
         *x
     }
+
+    // Issue #11366
+    let _: &mut u32 = match &mut Some(&mut 0u32) {
+        Some(x) => &mut *x,
+        None => panic!(),
+    };
 }

tests/ui/explicit_auto_deref.stderr

@@ -193,10 +193,10 @@ LL |     let _ = f_str(**ref_ref_str);
    |                   ^^^^^^^^^^^^^ help: try: `ref_ref_str`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:208:13
+  --> $DIR/explicit_auto_deref.rs:208:12
    |
 LL |     f_str(&&*ref_str); // `needless_borrow` will suggest removing both references
-   |             ^^^^^^^^ help: try: `ref_str`
+   |            ^^^^^^^^^ help: try: `ref_str`
 
 error: deref which would be done by auto-deref
   --> $DIR/explicit_auto_deref.rs:209:12
@@ -234,5 +234,11 @@ error: deref which would be done by auto-deref
 LL |         *x
    |         ^^ help: try: `x`
 
-error: aborting due to 39 previous errors
+error: deref which would be done by auto-deref
+  --> $DIR/explicit_auto_deref.rs:299:20
+   |
+LL |         Some(x) => &mut *x,
+   |                    ^^^^^^^ help: try: `x`
+
+error: aborting due to 40 previous errors