Merge pull request #3092 from illicitonion/issue-2879

default_trait_access skips <F as Default>::default()

clippy_lints/src/default_trait_access.rs

@@ -48,6 +48,17 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for DefaultTraitAccess {
             then {
                 match qpath {
                     QPath::Resolved(..) => {
+                        if_chain! {
+                            // Detect and ignore <Foo as Default>::default() because these calls do
+                            // explicitly name the type.
+                            if let ExprKind::Call(ref method, ref _args) = expr.node;
+                            if let ExprKind::Path(ref p) = method.node;
+                            if let QPath::Resolved(Some(_ty), _path) = p;
+                            then {
+                                return;
+                            }
+                        }
+
                         // TODO: Work out a way to put "whatever the imported way of referencing
                         // this type in this file" rather than a fully-qualified type.
                         let expr_ty = cx.tables.expr_ty(expr);

tests/ui/default_trait_access.rs

@@ -43,8 +43,10 @@ fn main() {
 
     let s18 = TupleStructDerivedDefault::default();
 
+    let s19 = <DerivedDefault as Default>::default();
+
     println!(
-        "[{}] [{}] [{}] [{}] [{}] [{}] [{}] [{}] [{}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}]",
+        "[{}] [{}] [{}] [{}] [{}] [{}] [{}] [{}] [{}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}] [{:?}], [{:?}]",
         s1,
         s2,
         s3,
@@ -63,6 +65,7 @@ fn main() {
         s16,
         s17,
         s18,
+        s19,
     );
 }