Use "Object" as the reified type of covariant override parameters.

pkg/analyzer/lib/src/dart/element/handle.dart

Index: pkg/analyzer/lib/src/dart/element/handle.dart
diff --git a/pkg/analyzer/lib/src/dart/element/handle.dart b/pkg/analyzer/lib/src/dart/element/handle.dart
index a1574550661aaa06e91add71f3fed407cfaf01aa..f8ae4a9fd69c7deeda777cf2a219572c34b8918b 100644
--- a/pkg/analyzer/lib/src/dart/element/handle.dart
+++ b/pkg/analyzer/lib/src/dart/element/handle.dart
@@ -409,7 +409,7 @@ abstract class ElementHandle implements Element {
       object is Element && object.location == _location;
 
   @override
-  /*=T*/ accept/*<T>*/(ElementVisitor<dynamic/*=T*/> visitor) =>
+  /*=T*/ accept/*<T>*/(ElementVisitor<dynamic/*=T*/ > visitor) =>
       actualElement.accept(visitor);
 
   @override
@@ -875,6 +875,10 @@ class MethodElementHandle extends ExecutableElementHandle
 
   @override
   MethodDeclaration computeNode() => actualElement.computeNode();
+
+  @override
+  FunctionType getReifiedType(DartType objectType) =>
+      actualElement.getReifiedType(objectType);
 }
 
 /**