Revert "Allow closures inside lazy initializers."

lib/compiler/implementation/resolver.dart

 // Copyright (c) 2012, 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.
 
 abstract class TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
   DartType getType(TypeAnnotation annotation);
   bool isParameterChecked(Element element);
 }
@@ skipping 1354 matching lines @@
   }
 
   visitFunctionExpression(FunctionExpression node) {
     visit(node.returnType);
     SourceString name;
     if (node.name === null) {
       name = const SourceString("");
     } else {
       name = node.name.asIdentifier().source;
     }
-    if (scope.element.kind == ElementKind.VARIABLE_LIST) {
-      compiler.internalError("Bad enclosing element", node: node);
-    }
     FunctionElement enclosing = new FunctionElement.node(
         name, node, ElementKind.FUNCTION, Modifiers.EMPTY,
         scope.element);
     setupFunction(node, enclosing);
     defineElement(node, enclosing, doAddToScope: node.name !== null);
 
     // Run the body in a fresh statement scope.
     StatementScope oldScope = statementScope;
     statementScope = new StatementScope();
     visit(node.body);
@@ skipping 1754 matching lines @@
     return result;
   }
   Element lookup(SourceString name) => localLookup(name);
   Element lexicalLookup(SourceString name) => localLookup(name);
 
   Element add(Element newElement) {
     throw "Cannot add an element in a patch library scope";
   }
   String toString() => 'PatchLibraryScope($origin,$patch)';
 }