With removal of increment operations, each node has a unique id.

runtime/vm/ast.h

Index: runtime/vm/ast.h
===================================================================
--- runtime/vm/ast.h	(revision 7508)
+++ runtime/vm/ast.h	(working copy)
@@ -105,18 +105,12 @@
 
   intptr_t token_index() const { return token_index_; }
 
-  virtual void SetIcDataAtId(intptr_t node_id, const ICData& value) {
-    ASSERT(id() == node_id);
-    set_ic_data(value);
-  }
 
-  virtual const ICData& ICDataAtId(intptr_t node_id) const {
-    ASSERT(id() == node_id);
-    return ic_data_;
+  const ICData& ic_data() const { return ic_data_; }
+  void set_ic_data(const ICData& value) {
+    ic_data_ = value.raw();
   }
 
-  virtual bool HasId(intptr_t value) const { return id_ == value; }
-
   intptr_t id() const { return id_; }
 
   void set_info(CodeGenInfo* info) { info_ = info; }
@@ -164,11 +158,6 @@
  protected:
   friend class ParsedFunction;
 
-  const ICData& ic_data() const { return ic_data_; }
-  void set_ic_data(const ICData& value) {
-    ic_data_ = value.raw();
-  }
-
   static intptr_t GetNextId() {
     Isolate* isolate = Isolate::Current();
     intptr_t tmp = isolate->ast_node_id();