Auto merge of #4776 - mikerite:fix-4727, r=flip1995

Fix crash in `use-self` lint

Fixes #4727

changelog: Fix crash in `use-self` lint

Author: bors

clippy_lints/src/use_self.rs

@@ -223,30 +223,32 @@ struct UseSelfVisitor<'a, 'tcx> {
 
 impl<'a, 'tcx> Visitor<'tcx> for UseSelfVisitor<'a, 'tcx> {
     fn visit_path(&mut self, path: &'tcx Path, _id: HirId) {
-        if path.segments.len() >= 2 {
-            let last_but_one = &path.segments[path.segments.len() - 2];
-            if last_but_one.ident.name != kw::SelfUpper {
-                let enum_def_id = match path.res {
-                    Res::Def(DefKind::Variant, variant_def_id) => self.cx.tcx.parent(variant_def_id),
-                    Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), ctor_def_id) => {
-                        let variant_def_id = self.cx.tcx.parent(ctor_def_id);
-                        variant_def_id.and_then(|def_id| self.cx.tcx.parent(def_id))
-                    },
-                    _ => None,
-                };
+        if !path.segments.iter().any(|p| p.ident.span.is_dummy()) {
+            if path.segments.len() >= 2 {
+                let last_but_one = &path.segments[path.segments.len() - 2];
+                if last_but_one.ident.name != kw::SelfUpper {
+                    let enum_def_id = match path.res {
+                        Res::Def(DefKind::Variant, variant_def_id) => self.cx.tcx.parent(variant_def_id),
+                        Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), ctor_def_id) => {
+                            let variant_def_id = self.cx.tcx.parent(ctor_def_id);
+                            variant_def_id.and_then(|def_id| self.cx.tcx.parent(def_id))
+                        },
+                        _ => None,
+                    };
 
-                if self.item_path.res.opt_def_id() == enum_def_id {
-                    span_use_self_lint(self.cx, path, Some(last_but_one));
+                    if self.item_path.res.opt_def_id() == enum_def_id {
+                        span_use_self_lint(self.cx, path, Some(last_but_one));
+                    }
                 }
             }
-        }
 
-        if path.segments.last().expect(SEGMENTS_MSG).ident.name != kw::SelfUpper {
-            if self.item_path.res == path.res {
-                span_use_self_lint(self.cx, path, None);
-            } else if let Res::Def(DefKind::Ctor(def::CtorOf::Struct, _), ctor_def_id) = path.res {
-                if self.item_path.res.opt_def_id() == self.cx.tcx.parent(ctor_def_id) {
+            if path.segments.last().expect(SEGMENTS_MSG).ident.name != kw::SelfUpper {
+                if self.item_path.res == path.res {
                     span_use_self_lint(self.cx, path, None);
+                } else if let Res::Def(DefKind::Ctor(def::CtorOf::Struct, _), ctor_def_id) = path.res {
+                    if self.item_path.res.opt_def_id() == self.cx.tcx.parent(ctor_def_id) {
+                        span_use_self_lint(self.cx, path, None);
+                    }
                 }
             }
         }

tests/ui/crashes/auxiliary/ice-4727-aux.rs

@@ -0,0 +1,9 @@
+pub trait Trait {
+    fn fun(par: &str) -> &str;
+}
+
+impl Trait for str {
+    fn fun(par: &str) -> &str {
+        &par[0..1]
+    }
+}

tests/ui/crashes/ice-4727.rs

@@ -0,0 +1,8 @@
+// run-pass
+
+#![warn(clippy::use_self)]
+
+#[path = "auxiliary/ice-4727-aux.rs"]
+mod aux;
+
+fn main() {}

tests/ui/use_self.fixed

@@ -1,4 +1,5 @@
 // run-rustfix
+// compile-flags: --edition 2018
 
 #![warn(clippy::use_self)]
 #![allow(dead_code)]
@@ -332,3 +333,32 @@ mod issue3567 {
         }
     }
 }
+
+mod paths_created_by_lowering {
+    use std::ops::Range;
+
+    struct S {}
+
+    impl S {
+        const A: usize = 0;
+        const B: usize = 1;
+
+        async fn g() -> Self {
+            Self {}
+        }
+
+        fn f<'a>(&self, p: &'a [u8]) -> &'a [u8] {
+            &p[Self::A..Self::B]
+        }
+    }
+
+    trait T {
+        fn f<'a>(&self, p: &'a [u8]) -> &'a [u8];
+    }
+
+    impl T for Range<u8> {
+        fn f<'a>(&self, p: &'a [u8]) -> &'a [u8] {
+            &p[0..1]
+        }
+    }
+}

tests/ui/use_self.rs

@@ -1,4 +1,5 @@
 // run-rustfix
+// compile-flags: --edition 2018
 
 #![warn(clippy::use_self)]
 #![allow(dead_code)]
@@ -332,3 +333,32 @@ mod issue3567 {
         }
     }
 }
+
+mod paths_created_by_lowering {
+    use std::ops::Range;
+
+    struct S {}
+
+    impl S {
+        const A: usize = 0;
+        const B: usize = 1;
+
+        async fn g() -> S {
+            S {}
+        }
+
+        fn f<'a>(&self, p: &'a [u8]) -> &'a [u8] {
+            &p[S::A..S::B]
+        }
+    }
+
+    trait T {
+        fn f<'a>(&self, p: &'a [u8]) -> &'a [u8];
+    }
+
+    impl T for Range<u8> {
+        fn f<'a>(&self, p: &'a [u8]) -> &'a [u8] {
+            &p[0..1]
+        }
+    }
+}