Erasure fix: Replace type parameters with dynamic instead of Object.

lib/transformations/erasure.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 library kernel.transformations.erasure;
 
 import '../ast.dart';
 import '../type_algebra.dart';
 
 /// This pass is a temporary measure to run strong mode code in the VM, which
 /// does not yet have the necessary runtime support.
@@ skipping 58 matching lines @@
       }
       // Skip the visitFunctionNode but traverse body.
       node.function.transformChildren(this);
       node.function.typeParameters.forEach(constantSubstitution.remove);
     } else {
       node.transformChildren(this);
     }
     return node;
   }
 
+  bool isObject(DartType type) {
+    return type is InterfaceType && type.classNode.supertype == null;
+  }
+
   @override
   visitFunctionNode(FunctionNode node) {
     for (var parameter in node.typeParameters) {
       substitution[parameter] = const DynamicType();
     }
     for (var parameter in node.typeParameters) {
-      substitution[parameter] = substitute(parameter.bound, substitution);
+      if (!isObject(parameter.bound)) {
+        substitution[parameter] = substitute(parameter.bound, substitution);
+      }
     }
     node.transformChildren(this);
     node.typeParameters.forEach(substitution.remove);
     node.typeParameters.clear();
     return node;
   }
 
   @override
   visitStaticInvocation(StaticInvocation node) {
     if (node.target.kind != ProcedureKind.Factory) {
@@ skipping 36 matching lines @@
   }
 
   @override
   visitMapLiteral(MapLiteral node) {
     if (node.isConst) pushConstantContext();
     node.transformChildren(this);
     if (node.isConst) popConstantContext();
     return node;
   }
 }