Fix some type warnings.

lib/compiler/implementation/elements/elements.dart

Index: lib/compiler/implementation/elements/elements.dart
diff --git a/lib/compiler/implementation/elements/elements.dart b/lib/compiler/implementation/elements/elements.dart
index 65b42a1b9becd8db7a27af80c5e6aa4c264bb15a..c952945533752d46febd528c1bb642548f8268ce 100644
--- a/lib/compiler/implementation/elements/elements.dart
+++ b/lib/compiler/implementation/elements/elements.dart
@@ -284,9 +284,6 @@ class Element implements Hashable {
     listener.cancel("Unimplemented cloneTo", element: this);
   }
 
-  Link<Type> get allSupertypesAndSelf() {
-    return allSupertypes.prepend(new InterfaceType(this));
-  }
 }
 
 class ContainerElement extends Element {
@@ -1110,8 +1107,9 @@ class ClassElement extends ScopeContainerElement
   Element lookupSuperInterfaceMember(SourceString memberName,
                                      LibraryElement fromLibrary) {
     bool isPrivate = memberName.isPrivate();
-    for (Type t in interfaces) {
-      Element e = t.element.lookupLocalMember(memberName);
+    for (InterfaceType t in interfaces) {
+      ClassElement cls = t.element;
+      Element e = cls.lookupLocalMember(memberName);
       if (e === null) continue;
       // Private members from a different library are not visible.
       if (isPrivate && fromLibrary !== e.getLibrary()) continue;
@@ -1309,6 +1307,10 @@ class ClassElement extends ScopeContainerElement
   ClassElement cloneTo(Element enclosing, DiagnosticListener listener) {
     listener.internalErrorOnElement(this, 'unsupported operation');
   }
+
+  Link<Type> get allSupertypesAndSelf() {
+    return allSupertypes.prepend(new InterfaceType(this));
+  }
 }
 
 class Elements {