Change TypeInference to handle super calls as direct invocations.

pkg/compiler/lib/src/inferrer/inferrer_visitor.dart

Index: pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
diff --git a/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart b/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
index bff02bd231a2291c9df27330cedaf468f1e50601..d011dc0d1977cf619e93499e794b3dd9fa01cbf7 100644
--- a/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
+++ b/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
@@ -958,13 +958,6 @@ abstract class InferrerVisitor<T, E extends MinimalInferrerEngine<T>>
     }
   }
 
-  T _superType;
-  T get superType {
-    if (_superType != null) return _superType;
-    return _superType =
-        types.nonNullExact(outermostElement.enclosingClass.superclass);
-  }
-
   @override
   T visitThisGet(Identifier node, _) {
     return thisType;
@@ -974,7 +967,7 @@ abstract class InferrerVisitor<T, E extends MinimalInferrerEngine<T>>
     if (node.isThis()) {
       return thisType;
     } else if (node.isSuper()) {
-      return superType;
+      return internalError(node, 'Unexpected expression $node.');
     } else {
       Element element = elements[node];
       if (Elements.isLocal(element)) {