Fix false positive in needless_pass_by_value trait methods

Author: sinkuu

clippy_lints/src/needless_pass_by_value.rs

@@ -87,7 +87,9 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessPassByValue {
 
         // Exclude non-inherent impls
         if let Some(NodeItem(item)) = cx.tcx.hir.find(cx.tcx.hir.get_parent_node(node_id)) {
-            if matches!(item.node, ItemImpl(_, _, _, _, Some(_), _, _) | ItemAutoImpl(..)) {
+            if matches!(item.node, ItemImpl(_, _, _, _, Some(_), _, _) | ItemAutoImpl(..) |
+                ItemTrait(..))
+            {
                 return;
             }
         }

tests/ui/needless_pass_by_value.rs

@@ -103,4 +103,11 @@ impl<T: Serialize, U> S<T, U> {
     }
 }
 
+trait FalsePositive {
+    fn visit_str(s: &str);
+    fn visit_string(s: String) {
+        Self::visit_str(&s);
+    }
+}
+
 fn main() {}