Allow a closure to be torn off from itself via .call.

sdk/lib/_internal/compiler/implementation/inferrer/closure_tracer.dart

 // Copyright (c) 2013, 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.
 
 part of type_graph_inferrer;
 
 class ClosureTracerVisitor extends TracerVisitor {
   final FunctionElement tracedElement;
 
   ClosureTracerVisitor(this.tracedElement, tracedType, inferrer)
@@ skipping 61 matching lines @@
 
   visitDynamicCallSiteTypeInformation(DynamicCallSiteTypeInformation info) {
     super.visitDynamicCallSiteTypeInformation(info);
     if (info.selector.isCall()) {
       if (info.arguments.contains(currentUser)
           && !info.targets.every((element) => element.isFunction())) {
         bailout('Passed to a closure');
       } else if (info.targets.any((element) => checkIfCurrentUser(element))) {
         analyzeCall(info);
       }
+    } else if (info.selector.isGetter() &&
+        info.selector.name == Compiler.CALL_OPERATOR_NAME) {
+      // We are potentially tearing off ourself here
+      addNewEscapeInformation(info);
     }
   }
 }
 
 class StaticTearOffClosureTracerVisitor extends ClosureTracerVisitor {
   StaticTearOffClosureTracerVisitor(tracedElement, tracedType, inferrer)
       : super(tracedElement, tracedType, inferrer);
 
   visitStaticCallSiteTypeInformation(StaticCallSiteTypeInformation info) {
     super.visitStaticCallSiteTypeInformation(info);
     if (info.calledElement == tracedElement
         && info.selector != null
         && info.selector.isGetter()) {
       addNewEscapeInformation(info);
     }
   }
 }