Verify AST instead of constant values.

pkg/analyzer/tool/summary/idl.dart

 // Copyright (c) 2015, 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.
 
 /**
  * This file is an "idl" style description of the summary format.  It is not
  * executed directly; instead it is parsed and transformed into code that
  * implements the summary format.
  *
  * The code generation process introduces the following non-typical semantics:
@@ skipping 619 matching lines @@
 
   /**
    * Pop the top 2 values from the stack, pass them to the predefined Dart
    * function `identical`, and push the result back onto the stack.
    */
   identical,
 
   /**
    * Pop the top 2 values from the stack, evaluate `v1 == v2`, and push the
    * result back onto the stack.
-   *
-   * This is also used to represent `v1 != v2`, by composition with [not].
    */
   equal,
 
   /**
+   * Pop the top 2 values from the stack, evaluate `v1 != v2`, and push the
+   * result back onto the stack.
+   */
+  notEqual,
+
+  /**
    * Pop the top value from the stack, compute its boolean negation, and push
    * the result back onto the stack.
    */
   not,
 
   /**
    * Pop the top 2 values from the stack, compute `v1 && v2`, and push the
    * result back onto the stack.
    */
   and,
@@ skipping 803 matching lines @@
   int propagatedTypeSlot;
 
   /**
    * If this variable is inferrable, nonzero slot id identifying which entry in
    * [LinkedLibrary.types] contains the inferred type for this variable.  If
    * there is no matching entry in [LinkedLibrary.types], then no type was
    * inferred for this variable, so its static type is `dynamic`.
    */
   int inferredTypeSlot;
 }