Fix suggestion on fully qualified syntax

clippy_lints/src/dereference.rs

@@ -155,7 +155,7 @@ impl_lint_pass!(Dereferencing<'_> => [
 
 #[derive(Default)]
 pub struct Dereferencing<'tcx> {
-    state: Option<(State, StateData)>,
+    state: Option<(State<'tcx>, StateData)>,
 
     // While parsing a `deref` method call in ufcs form, the path to the function is itself an
     // expression. This is to store the id of that expression so it can be skipped when
@@ -210,12 +210,13 @@ struct DerefedBorrow {
 }
 
 #[derive(Debug)]
-enum State {
+enum State<'tcx> {
     // Any number of deref method calls.
     DerefMethod {
         // The number of calls in a sequence which changed the referenced type
         ty_changed_count: usize,
         is_final_ufcs: bool,
+        call_args: Option<&'tcx [Expr<'tcx>]>,
         /// The required mutability
         target_mut: Mutability,
     },
@@ -312,10 +313,16 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing<'tcx> {
                             && position.lint_explicit_deref() =>
                     {
                         let ty_changed_count = usize::from(!deref_method_same_type(expr_ty, typeck.expr_ty(sub_expr)));
+                        let (is_final_ufcs, call_args) = if let ExprKind::Call(_, args) = expr.kind {
+                            (true, Some(args))
+                        } else {
+                            (false, None)
+                        };
                         self.state = Some((
                             State::DerefMethod {
                                 ty_changed_count,
-                                is_final_ufcs: matches!(expr.kind, ExprKind::Call(..)),
+                                is_final_ufcs,
+                                call_args,
                                 target_mut,
                             },
                             StateData {
@@ -438,6 +445,7 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing<'tcx> {
                             ty_changed_count + 1
                         },
                         is_final_ufcs: matches!(expr.kind, ExprKind::Call(..)),
+                        call_args: None,
                         target_mut,
                     },
                     data,
@@ -1472,11 +1480,12 @@ fn ty_contains_field(ty: Ty<'_>, name: Symbol) -> bool {
 }
 
 #[expect(clippy::needless_pass_by_value, clippy::too_many_lines)]
-fn report<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, state: State, data: StateData) {
+fn report<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, state: State<'_>, data: StateData) {
     match state {
         State::DerefMethod {
             ty_changed_count,
             is_final_ufcs,
+            call_args,
             target_mut,
         } => {
             let mut app = Applicability::MachineApplicable;
@@ -1503,12 +1512,25 @@ fn report<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, state: State, data
                 "&"
             };
 
-            let expr_str = if !expr_is_macro_call && is_final_ufcs && expr.precedence().order() < PREC_PREFIX {
+            let mut expr_str = if !expr_is_macro_call && is_final_ufcs && expr.precedence().order() < PREC_PREFIX {
                 format!("({expr_str})")
             } else {
                 expr_str.into_owned()
             };
 
+            // Fix #10850, changes suggestion if it's `Foo::deref` instead of `foo.deref`. Since `Foo::deref` is
+            // a `Call` instead of a `MethodCall` this should catch all instances of this, even if it's fully
+            // qualified or whatnot.
+            if is_final_ufcs && let Some(args) = call_args {
+                // Remove ref if it's there
+                let arg = if let ExprKind::AddrOf(.., arg) = args[0].kind {
+                    arg
+                } else {
+                    &args[0]
+                };
+                expr_str = snippet_with_applicability(cx, arg.span, "{ .. }", &mut app).to_string();
+            }
+
             span_lint_and_sugg(
                 cx,
                 EXPLICIT_DEREF_METHODS,

tests/ui/explicit_deref_methods.fixed

@@ -1,11 +1,12 @@
 //@run-rustfix
 #![warn(clippy::explicit_deref_methods)]
-#![allow(unused_variables)]
+#![allow(unused_variables, unused_must_use)]
 #![allow(
     clippy::borrow_deref_ref,
     suspicious_double_ref_op,
     clippy::explicit_auto_deref,
     clippy::needless_borrow,
+    clippy::no_effect,
     clippy::uninlined_format_args
 )]
 
@@ -28,6 +29,22 @@ impl Deref for CustomVec {
     }
 }
 
+struct Aaa;
+
+impl Deref for Aaa {
+    type Target = ();
+
+    fn deref(&self) -> &Self::Target {
+        todo!();
+    }
+}
+
+impl DerefMut for Aaa {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        todo!();
+    }
+}
+
 fn main() {
     let a: &mut String = &mut String::from("foo");
 
@@ -58,6 +75,16 @@ fn main() {
     let opt_a = Some(a.clone());
     let b = &*opt_a.unwrap();
 
+    // make sure `Aaa::deref` instead of `aaa.deref()` works as well as fully qualified syntax
+
+    &*Aaa;
+    &mut *Aaa;
+    &*Aaa;
+    &mut *Aaa;
+    let mut aaa = Aaa;
+    &*aaa;
+    &mut *aaa;
+
     // following should not require linting
 
     let cv = CustomVec(vec![0, 42]);

tests/ui/explicit_deref_methods.rs

@@ -1,11 +1,12 @@
 //@run-rustfix
 #![warn(clippy::explicit_deref_methods)]
-#![allow(unused_variables)]
+#![allow(unused_variables, unused_must_use)]
 #![allow(
     clippy::borrow_deref_ref,
     suspicious_double_ref_op,
     clippy::explicit_auto_deref,
     clippy::needless_borrow,
+    clippy::no_effect,
     clippy::uninlined_format_args
 )]
 
@@ -28,6 +29,22 @@ impl Deref for CustomVec {
     }
 }
 
+struct Aaa;
+
+impl Deref for Aaa {
+    type Target = ();
+
+    fn deref(&self) -> &Self::Target {
+        todo!();
+    }
+}
+
+impl DerefMut for Aaa {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        todo!();
+    }
+}
+
 fn main() {
     let a: &mut String = &mut String::from("foo");
 
@@ -58,6 +75,16 @@ fn main() {
     let opt_a = Some(a.clone());
     let b = opt_a.unwrap().deref();
 
+    // make sure `Aaa::deref` instead of `aaa.deref()` works as well as fully qualified syntax
+
+    Aaa::deref(&Aaa);
+    Aaa::deref_mut(&mut Aaa);
+    <Aaa as Deref>::deref(&Aaa);
+    <Aaa as DerefMut>::deref_mut(&mut Aaa);
+    let mut aaa = Aaa;
+    Aaa::deref(&aaa);
+    Aaa::deref_mut(&mut aaa);
+
     // following should not require linting
 
     let cv = CustomVec(vec![0, 42]);

tests/ui/explicit_deref_methods.stderr

@@ -1,5 +1,5 @@
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:36:19
+  --> $DIR/explicit_deref_methods.rs:53:19
    |
 LL |     let b: &str = a.deref();
    |                   ^^^^^^^^^ help: try this: `&*a`
@@ -7,70 +7,106 @@ LL |     let b: &str = a.deref();
    = note: `-D clippy::explicit-deref-methods` implied by `-D warnings`
 
 error: explicit `deref_mut` method call
-  --> $DIR/explicit_deref_methods.rs:38:23
+  --> $DIR/explicit_deref_methods.rs:55:23
    |
 LL |     let b: &mut str = a.deref_mut();
    |                       ^^^^^^^^^^^^^ help: try this: `&mut **a`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:41:39
+  --> $DIR/explicit_deref_methods.rs:58:39
    |
 LL |     let b: String = format!("{}, {}", a.deref(), a.deref());
    |                                       ^^^^^^^^^ help: try this: `&*a`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:41:50
+  --> $DIR/explicit_deref_methods.rs:58:50
    |
 LL |     let b: String = format!("{}, {}", a.deref(), a.deref());
    |                                                  ^^^^^^^^^ help: try this: `&*a`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:43:20
+  --> $DIR/explicit_deref_methods.rs:60:20
    |
 LL |     println!("{}", a.deref());
    |                    ^^^^^^^^^ help: try this: `&*a`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:46:11
+  --> $DIR/explicit_deref_methods.rs:63:11
    |
 LL |     match a.deref() {
    |           ^^^^^^^^^ help: try this: `&*a`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:50:28
+  --> $DIR/explicit_deref_methods.rs:67:28
    |
 LL |     let b: String = concat(a.deref());
    |                            ^^^^^^^^^ help: try this: `&*a`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:52:13
+  --> $DIR/explicit_deref_methods.rs:69:13
    |
 LL |     let b = just_return(a).deref();
    |             ^^^^^^^^^^^^^^^^^^^^^^ help: try this: `just_return(a)`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:54:28
+  --> $DIR/explicit_deref_methods.rs:71:28
    |
 LL |     let b: String = concat(just_return(a).deref());
    |                            ^^^^^^^^^^^^^^^^^^^^^^ help: try this: `just_return(a)`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:56:19
+  --> $DIR/explicit_deref_methods.rs:73:19
    |
 LL |     let b: &str = a.deref().deref();
    |                   ^^^^^^^^^^^^^^^^^ help: try this: `&**a`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:59:13
+  --> $DIR/explicit_deref_methods.rs:76:13
    |
 LL |     let b = opt_a.unwrap().deref();
    |             ^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&*opt_a.unwrap()`
 
 error: explicit `deref` method call
-  --> $DIR/explicit_deref_methods.rs:85:31
+  --> $DIR/explicit_deref_methods.rs:80:5
+   |
+LL |     Aaa::deref(&Aaa);
+   |     ^^^^^^^^^^^^^^^^ help: try this: `&*Aaa`
+
+error: explicit `deref_mut` method call
+  --> $DIR/explicit_deref_methods.rs:81:5
+   |
+LL |     Aaa::deref_mut(&mut Aaa);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut *Aaa`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:82:5
+   |
+LL |     <Aaa as Deref>::deref(&Aaa);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&*Aaa`
+
+error: explicit `deref_mut` method call
+  --> $DIR/explicit_deref_methods.rs:83:5
+   |
+LL |     <Aaa as DerefMut>::deref_mut(&mut Aaa);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut *Aaa`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:85:5
+   |
+LL |     Aaa::deref(&aaa);
+   |     ^^^^^^^^^^^^^^^^ help: try this: `&*aaa`
+
+error: explicit `deref_mut` method call
+  --> $DIR/explicit_deref_methods.rs:86:5
+   |
+LL |     Aaa::deref_mut(&mut aaa);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut *aaa`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:112:31
    |
 LL |     let b: &str = expr_deref!(a.deref());
    |                               ^^^^^^^^^ help: try this: `&*a`
 
-error: aborting due to 12 previous errors
+error: aborting due to 18 previous errors