closure calls (just the invocation part).

frog/leg/compiler.dart

 // Copyright (c) 2011, 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.
 
 class WorkElement {
   final Element element;
   TreeElements resolutionTree;
   Function run;
 
   WorkElement.toCompile(this.element) : resolutionTree = null {
@@ skipping 58 matching lines @@
 
   void ensure(bool condition) {
     if (!condition) cancel('failed assertion in leg');
   }
 
   void unimplemented(String methodName,
                      [Node node, Token token, HInstruction instruction]) {
     cancel("$methodName not implemented", node, token, instruction);
   }
 
+  void internalError(String message,
+                     [Node node, Token token, HInstruction instruction]) {
+    cancel("Internal Error: $message", node, token, instruction);
+  }
+
   void cancel([String reason, Node node, Token token,
                HInstruction instruction]) {
     throw new CompilerCancelledException(reason);
   }
 
   void log(message) {
     // Do nothing.
   }
 
   bool run(Script script) {
@@ skipping 156 matching lines @@
 
 class CompilerCancelledException implements Exception {
   final String reason;
   CompilerCancelledException(this.reason);
 
   String toString() {
     String banner = 'compiler cancelled';
     return (reason !== null) ? '$banner: $reason' : '$banner';
   }
 }