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

[rust.git] / clippy_lints / src / default_trait_access.rs

diff --git a/clippy_lints/src/default_trait_access.rs b/clippy_lints/src/default_trait_access.rs
index 0222f896e28f8371b9633e933f03c12ae6206143..d3598a5bdaae729416ac606e5019331b3bbaaad0 100644 (file)
--- a/clippy_lints/src/default_trait_access.rs
+++ b/clippy_lints/src/default_trait_access.rs
@@ -1,7 +1,10 @@
 use rustc::hir::*;
 use rustc::lint::*;
+use rustc::{declare_lint, lint_array};
+use if_chain::if_chain;
+use rustc::ty::TyKind;
 
-use crate::utils::{match_def_path, opt_def_id, paths, span_lint_and_sugg};
+use crate::utils::{any_parent_is_automatically_derived, match_def_path, opt_def_id, paths, span_lint_and_sugg};
 
 
 /// **What it does:** Checks for literal calls to `Default::default()`.
@@ -21,7 +24,7 @@
 /// ```
 declare_clippy_lint! {
     pub DEFAULT_TRAIT_ACCESS,
-    style,
+    pedantic,
     "checks for literal calls to Default::default()"
 }
 
@@ -37,23 +40,34 @@ fn get_lints(&self) -> LintArray {
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for DefaultTraitAccess {
     fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
         if_chain! {
-            if let ExprCall(ref path, ..) = expr.node;
-            if let ExprPath(ref qpath) = path.node;
+            if let ExprKind::Call(ref path, ..) = expr.node;
+            if !any_parent_is_automatically_derived(cx.tcx, expr.id);
+            if let ExprKind::Path(ref qpath) = path.node;
             if let Some(def_id) = opt_def_id(cx.tables.qpath_def(qpath, path.hir_id));
             if match_def_path(cx.tcx, def_id, &paths::DEFAULT_TRAIT_METHOD);
             then {
                 match qpath {
                     QPath::Resolved(..) => {
+                        if let ExprKind::Call(ref method, ref _args) = expr.node {
+                            if format!("{:?}", method).contains(" as Default>") {
+                                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 replacement = format!("{}::default()", cx.tables.expr_ty(expr));
-                        span_lint_and_sugg(
-                            cx,
-                            DEFAULT_TRAIT_ACCESS,
-                            expr.span,
-                            &format!("Calling {} is more clear than this expression", replacement),
-                            "try",
-                            replacement);
+                        let expr_ty = cx.tables.expr_ty(expr);
+                        if let TyKind::Adt(..) = expr_ty.sty {
+                            let replacement = format!("{}::default()", expr_ty);
+                            span_lint_and_sugg(
+                                cx,
+                                DEFAULT_TRAIT_ACCESS,
+                                expr.span,
+                                &format!("Calling {} is more clear than this expression", replacement),
+                                "try",
+                                replacement);
+                         }
                     },
                     QPath::TypeRelative(..) => {},
                 }