Add an assigned variables analysis....

src/ast.cc

Index: src/ast.cc
===================================================================
--- src/ast.cc	(revision 4066)
+++ src/ast.cc	(working copy)
@@ -58,13 +58,27 @@
 // ----------------------------------------------------------------------------
 // Implementation of other node functionality.
 
+Assignment* ExpressionStatement::StatementAsSimpleAssignment() {
+  return (expression()->AsAssignment() != NULL &&
+          !expression()->AsAssignment()->is_compound())
+      ? expression()->AsAssignment()
+      : NULL;
+}
+
+
+CountOperation* ExpressionStatement::StatementAsCountOperation() {
+  return expression()->AsCountOperation();
+}
+
+
 VariableProxy::VariableProxy(Handle<String> name,
                              bool is_this,
                              bool inside_with)
   : name_(name),
     var_(NULL),
     is_this_(is_this),
-    inside_with_(inside_with) {
+    inside_with_(inside_with),
+    is_trivial_(false) {
   // names must be canonicalized for fast equality checks
   ASSERT(name->IsSymbol());
 }