Auto merge of #8899 - botahamec:use-self-tuple-struct-variants, r=Alexendoo

Fix `[use_self]` false negative with on struct and tuple struct patterns

fixes #8845

changelog: Triggered the warning for ``[`use_self`]`` on `TupleStruct` and `Struct` patterns, whereas currently it's only triggered for `Path` patterns

Author: bors

clippy_lints/src/use_self.rs

@@ -258,13 +258,21 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
             if !pat.span.from_expansion();
             if meets_msrv(self.msrv, msrvs::TYPE_ALIAS_ENUM_VARIANTS);
             if let Some(&StackItem::Check { impl_id, .. }) = self.stack.last();
-            if let PatKind::Path(QPath::Resolved(_, path)) = pat.kind;
-            if !matches!(path.res, Res::SelfTy { .. } | Res::Def(DefKind::TyParam, _));
+            // get the path from the pattern
+            if let PatKind::Path(QPath::Resolved(_, path))
+                 | PatKind::TupleStruct(QPath::Resolved(_, path), _, _)
+                 | PatKind::Struct(QPath::Resolved(_, path), _, _) = pat.kind;
             if cx.typeck_results().pat_ty(pat) == cx.tcx.type_of(impl_id);
-            if let [first, ..] = path.segments;
-            if let Some(hir_id) = first.hir_id;
             then {
-                span_lint(cx, cx.tcx.hir().span(hir_id));
+                match path.res {
+                    Res::Def(DefKind::Ctor(ctor_of, _), ..) => match ctor_of {
+                            CtorOf::Variant => lint_path_to_variant(cx, path),
+                            CtorOf::Struct => span_lint(cx, path.span),
+                    },
+                    Res::Def(DefKind::Variant, ..) => lint_path_to_variant(cx, path),
+                    Res::Def(DefKind::Struct, ..) => span_lint(cx, path.span),
+                    _ => ()
+                }
             }
         }
     }

tests/ui/use_self.fixed

@@ -542,3 +542,69 @@ mod use_self_in_pat {
         }
     }
 }
+
+mod issue8845 {
+    pub enum Something {
+        Num(u8),
+        TupleNums(u8, u8),
+        StructNums { one: u8, two: u8 },
+    }
+
+    struct Foo(u8);
+
+    struct Bar {
+        x: u8,
+        y: usize,
+    }
+
+    impl Something {
+        fn get_value(&self) -> u8 {
+            match self {
+                Self::Num(n) => *n,
+                Self::TupleNums(n, _m) => *n,
+                Self::StructNums { one, two: _ } => *one,
+            }
+        }
+
+        fn use_crate(&self) -> u8 {
+            match self {
+                Self::Num(n) => *n,
+                Self::TupleNums(n, _m) => *n,
+                Self::StructNums { one, two: _ } => *one,
+            }
+        }
+
+        fn imported_values(&self) -> u8 {
+            use Something::*;
+            match self {
+                Num(n) => *n,
+                TupleNums(n, _m) => *n,
+                StructNums { one, two: _ } => *one,
+            }
+        }
+    }
+
+    impl Foo {
+        fn get_value(&self) -> u8 {
+            let Self(x) = self;
+            *x
+        }
+
+        fn use_crate(&self) -> u8 {
+            let Self(x) = self;
+            *x
+        }
+    }
+
+    impl Bar {
+        fn get_value(&self) -> u8 {
+            let Self { x, .. } = self;
+            *x
+        }
+
+        fn use_crate(&self) -> u8 {
+            let Self { x, .. } = self;
+            *x
+        }
+    }
+}

tests/ui/use_self.rs

@@ -542,3 +542,69 @@ mod use_self_in_pat {
         }
     }
 }
+
+mod issue8845 {
+    pub enum Something {
+        Num(u8),
+        TupleNums(u8, u8),
+        StructNums { one: u8, two: u8 },
+    }
+
+    struct Foo(u8);
+
+    struct Bar {
+        x: u8,
+        y: usize,
+    }
+
+    impl Something {
+        fn get_value(&self) -> u8 {
+            match self {
+                Something::Num(n) => *n,
+                Something::TupleNums(n, _m) => *n,
+                Something::StructNums { one, two: _ } => *one,
+            }
+        }
+
+        fn use_crate(&self) -> u8 {
+            match self {
+                crate::issue8845::Something::Num(n) => *n,
+                crate::issue8845::Something::TupleNums(n, _m) => *n,
+                crate::issue8845::Something::StructNums { one, two: _ } => *one,
+            }
+        }
+
+        fn imported_values(&self) -> u8 {
+            use Something::*;
+            match self {
+                Num(n) => *n,
+                TupleNums(n, _m) => *n,
+                StructNums { one, two: _ } => *one,
+            }
+        }
+    }
+
+    impl Foo {
+        fn get_value(&self) -> u8 {
+            let Foo(x) = self;
+            *x
+        }
+
+        fn use_crate(&self) -> u8 {
+            let crate::issue8845::Foo(x) = self;
+            *x
+        }
+    }
+
+    impl Bar {
+        fn get_value(&self) -> u8 {
+            let Bar { x, .. } = self;
+            *x
+        }
+
+        fn use_crate(&self) -> u8 {
+            let crate::issue8845::Bar { x, .. } = self;
+            *x
+        }
+    }
+}

tests/ui/use_self.stderr

@@ -186,5 +186,65 @@ error: unnecessary structure name repetition
 LL |             if let Foo::Bar = self {
    |                    ^^^ help: use the applicable keyword: `Self`
 
-error: aborting due to 31 previous errors
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:563:17
+   |
+LL |                 Something::Num(n) => *n,
+   |                 ^^^^^^^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:564:17
+   |
+LL |                 Something::TupleNums(n, _m) => *n,
+   |                 ^^^^^^^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:565:17
+   |
+LL |                 Something::StructNums { one, two: _ } => *one,
+   |                 ^^^^^^^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:571:17
+   |
+LL |                 crate::issue8845::Something::Num(n) => *n,
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:572:17
+   |
+LL |                 crate::issue8845::Something::TupleNums(n, _m) => *n,
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:573:17
+   |
+LL |                 crate::issue8845::Something::StructNums { one, two: _ } => *one,
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:589:17
+   |
+LL |             let Foo(x) = self;
+   |                 ^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:594:17
+   |
+LL |             let crate::issue8845::Foo(x) = self;
+   |                 ^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:601:17
+   |
+LL |             let Bar { x, .. } = self;
+   |                 ^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:606:17
+   |
+LL |             let crate::issue8845::Bar { x, .. } = self;
+   |                 ^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
+
+error: aborting due to 41 previous errors