Deprecate the FxHashMap() and FxHashSet() constructor function hack

Author: oli-obk

src/librustc/dep_graph/cgu_reuse_tracker.rs

@@ -51,8 +51,8 @@ pub struct CguReuseTracker {
 impl CguReuseTracker {
     pub fn new() -> CguReuseTracker {
         let data = TrackerData {
-            actual_reuse: FxHashMap(),
-            expected_reuse: FxHashMap(),
+            actual_reuse: FxHashMap::default(),
+            expected_reuse: FxHashMap::default(),
         };
 
         CguReuseTracker {

src/librustc/dep_graph/dep_tracking_map.rs

@@ -36,7 +36,7 @@ impl<M: DepTrackingMapConfig> DepTrackingMap<M> {
         DepTrackingMap {
             phantom: PhantomData,
             graph,
-            map: FxHashMap(),
+            map: FxHashMap::default(),
         }
     }
 }