Support default values for optional parameters.

dart/frog/leg/compiler.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.
 
 class WorkItem {
   final Element element;
   TreeElements resolutionTree;
   Function run;
   Map<int, BailoutInfo> bailouts = null;
 
@@ skipping 194 matching lines @@
     return elements;
   }
 
   TreeElements analyze(WorkItem work) {
     work.resolutionTree = analyzeElement(work.element);
     return work.resolutionTree;
   }
 
   String codegen(WorkItem work) {
     String code;
-    if (work.element.kind == ElementKind.FIELD) {
+    if (work.element.kind == ElementKind.FIELD
+        || work.element.kind == ElementKind.PARAMETER) {
       compileTimeConstantHandler.compileWorkItem(work);
       return null;
     } else {
       HGraph graph = builder.build(work);
       optimizer.optimize(work, graph);
       code = generator.generate(work, graph);
       universe.addGeneratedCode(work, code);
       return code;
     }
   }
@@ skipping 38 matching lines @@
   }
 
   Type resolveType(ClassElement element) {
     return resolver.resolveType(element);
   }
 
   FunctionParameters resolveSignature(FunctionElement element) {
     return resolver.resolveSignature(element);
   }
 
+  Object compileVariable(VariableElement element) {
+    Element savedElement = currentElement;
+    currentElement = element;
+    compile(new WorkItem.toCompile(element));
+    currentElement = savedElement;
+    return compileTimeConstantHandler.compileVariable(element);
+  }
+
   reportWarning(Node node, var message) {}
   reportError(Node node, var message) {}
 
   Script readScript(String filename) {
     unimplemented('Compiler.readScript');
   }
 
   String get legDirectory() {
     unimplemented('Compiler.legDirectory');
   }
@@ skipping 24 matching lines @@
 
 class CompilerCancelledException implements Exception {
   final String reason;
   CompilerCancelledException(this.reason);
 
   String toString() {
     String banner = 'compiler cancelled';
     return (reason !== null) ? '$banner: $reason' : '$banner';
   }
 }