Adjust error code

src/librustc_typeck/coherence/overlap.rs

@@ -120,7 +120,7 @@ fn visit_item(&mut self, item: &'v hir::Item) {
                 if let Some(prev_id) = prev_default_impl {
                     let mut err = struct_span_err!(
                         self.tcx.sess,
-                        self.tcx.span_of_impl(impl_def_id).unwrap(), E0519,
+                        self.tcx.span_of_impl(impl_def_id).unwrap(), E0521,
                         "redundant default implementations of trait `{}`:",
                         trait_ref);
                     err.span_note(self.tcx.span_of_impl(self.tcx.map.local_def_id(prev_id))

src/librustc_typeck/diagnostics.rs

@@ -3696,6 +3696,6 @@ fn main() {
            // type `{}` was overridden
     E0436, // functional record update requires a struct
     E0513, // no type for local variable ..
-    E0519, // redundant default implementations of trait
-    E0520  // cannot specialize non-default item
+    E0520, // cannot specialize non-default item
+    E0521  // redundant default implementations of trait
 }