Auto merge of rust-lang#6004 - mikerite:default-trait-access-20200904, r=ebroto

Simplify `clippy::default_trait_access`

Remove repeated matching on the same QPath.

changelog: none

Author: bors

clippy_lints/src/default_trait_access.rs

@@ -38,37 +38,23 @@ impl<'tcx> LateLintPass<'tcx> for DefaultTraitAccess {
             if let ExprKind::Path(ref qpath) = path.kind;
             if let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id();
             if match_def_path(cx, def_id, &paths::DEFAULT_TRAIT_METHOD);
+            // Detect and ignore <Foo as Default>::default() because these calls do explicitly name the type.
+            if let QPath::Resolved(None, _path) = qpath;
             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.kind;
-                            if let ExprKind::Path(ref p) = method.kind;
-                            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.typeck_results().expr_ty(expr);
-                        if let ty::Adt(def, ..) = expr_ty.kind {
-                            let replacement = format!("{}::default()", cx.tcx.def_path_str(def.did));
-                            span_lint_and_sugg(
-                                cx,
-                                DEFAULT_TRAIT_ACCESS,
-                                expr.span,
-                                &format!("calling `{}` is more clear than this expression", replacement),
-                                "try",
-                                replacement,
-                                Applicability::Unspecified, // First resolve the TODO above
-                            );
-                         }
-                    },
-                    QPath::TypeRelative(..) | QPath::LangItem(..) => {},
+                let expr_ty = cx.typeck_results().expr_ty(expr);
+                if let ty::Adt(def, ..) = expr_ty.kind {
+                    // 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 replacement = format!("{}::default()", cx.tcx.def_path_str(def.did));
+                    span_lint_and_sugg(
+                        cx,
+                        DEFAULT_TRAIT_ACCESS,
+                        expr.span,
+                        &format!("calling `{}` is more clear than this expression", replacement),
+                        "try",
+                        replacement,
+                        Applicability::Unspecified, // First resolve the TODO above
+                    );
                 }
             }
         }