closure calls (just the invocation part).

frog/leg/elements/elements.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.
 
 #library('elements');
 
 #import('../tree/tree.dart');
 #import('../scanner/scannerlib.dart');
 #import('../leg.dart');  // TODO(karlklose): we only need type.
 #import('../util/util.dart');
@@ skipping 39 matching lines @@
   abstract Type computeType(Compiler compiler, Types types);
   Modifiers get modifiers() => null;
 
   bool isFunction() => kind == ElementKind.FUNCTION;
   bool isMember() =>
       enclosingElement !== null && enclosingElement.kind == ElementKind.CLASS;
   bool isInstanceMember() => false;
   bool isFactoryConstructor() => modifiers != null && modifiers.isFactory();
   bool isGenerativeConstructor() => kind == ElementKind.GENERATIVE_CONSTRUCTOR;
   bool isCompilationUnit() => kind == ElementKind.COMPILATION_UNIT;
+  bool isVariable() => kind == ElementKind.VARIABLE;
+  bool isParameter() => kind == ElementKind.PARAMETER;
 
   bool isAssignable() {
     if (modifiers != null && modifiers.isFinal()) return false;
     if (isFunction() || isGenerativeConstructor()) return false;
     return true;
   }
 
   const Element(this.name, this.kind, this.enclosingElement);
 
   // TODO(kasperl): This is a very bad hash code for the element and
@@ skipping 292 matching lines @@
     return (element != null)
            && !element.isInstanceMember()
            && (element.kind === ElementKind.FIELD);
   }
 
   static bool isInstanceMethod(Element element) {
     return (element != null)
            && element.isInstanceMember()
            && (element.kind === ElementKind.FUNCTION);
   }
+
+  static bool isClosureSend(Send send, TreeElements elements) {
+    if (send.isPropertyAccess) return false;
+    if (send.receiver !== null) return false;
+    Element element = elements[send];
+    // (o)() or foo()().
+    if (element === null && send.selector.asIdentifier() === null) return true;
+    // foo() with foo a local or a parameter.
+    return element.isVariable() || element.isParameter();
+  }
 }