Replace 'length' with more generic 'extractProperty' operation.

pkg/analyzer/lib/src/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
  * contains abstract classes which declare the interface for reading data from
  * summaries.  It is parsed and transformed into code that implements the
  * summary format.
  *
@@ skipping 700 matching lines @@
    * class.
    */
   propertyAccessor,
 
   /**
    * The entity is a method.
    */
   method,
 
   /**
-   * The `length` property access.
-   */
-  length,
-
-  /**
    * The entity is a typedef.
    */
   typedef,
 
   /**
    * The entity is a local function.
    */
   function,
 
   /**
@@ skipping 386 matching lines @@
    * - A qualified reference to a static constant variable (e.g. `C.v`, where
    *   C is a class and `v` is a constant static variable in `C`).
    * - An identifier expression referring to a constant variable.
    * - A simple or qualified identifier denoting a class or type alias.
    * - A simple or qualified identifier denoting a top-level function or a
    *   static method.
    */
   pushReference,
 
   /**
+   * Pop the top value from the stack, extract the value of the property with
+   * the name obtained from [UnlinkedConst.strings], and push the result back
+   * onto the stack.
+   */
+  extractProperty,
+
+  /**
    * Pop the top `n` values from the stack (where `n` is obtained from
    * [UnlinkedConst.ints]) into a list (filled from the end) and take the next
    * `n` values from [UnlinkedConst.strings] and use the lists of names and
    * values to create named arguments.  Then pop the top `m` values from the
    * stack (where `m` is obtained from [UnlinkedConst.ints]) into a list (filled
    * from the end) and use them as positional arguments.  Use the lists of
    * positional and names arguments to invoke a constant constructor obtained
    * from [UnlinkedConst.references], and push the resulting value back onto the
    * stack.
    *
@@ skipping 173 matching lines @@
    * Pop the top 2 values from the stack, compute `v1 % v2`, and push the
    * result back onto the stack.
    */
   modulo,
 
   /**
    * Pop the top 3 values from the stack, compute `v1 ? v2 : v3`, and push the
    * result back onto the stack.
    */
   conditional,
-
-  /**
-   * Pop the top value from the stack, evaluate `v.length`, and push the result
-   * back onto the stack.
-   */
-  length,
 }
 
 /**
  * Unlinked summary information about a constructor initializer.
  */
 abstract class UnlinkedConstructorInitializer extends base.SummaryClass {
   /**
    * If [kind] is `thisInvocation` or `superInvocation`, the arguments of the
    * invocation.  Otherwise empty.
    */
@@ skipping 1120 matching lines @@
    */
   @Id(11)
   int get visibleLength;
 
   /**
    * If a local variable, the beginning of the visible range; zero otherwise.
    */
   @Id(12)
   int get visibleOffset;
 }