Add a unit index to prelinked type references in summaries.

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 107 matching lines @@
    * Index into [UnlinkedLibrary.dependencies] indicating which imported library
    * declares the entity being referred to.
    */
   int dependency;
 
   /**
    * The kind of the entity being referred to.  For the pseudo-type `dynamic`,
    * the kind if [PrelinkedReferenceKind.classOrEnum].
    */
   PrelinkedReferenceKind kind;
+
+  /**
+   * Integer index indicating which unit in the imported library contains the
+   * definition of the entity.  As with indices into [UnlinkedLibrary.units],
+   * zero represents the defining compilation unit, and nonzero values
+   * represent parts in the order of the corresponding `part` declarations.
+   */
+  int unit;
 }
 
 /**
  * Enum used to indicate the kind of entity referred to by a
  * [PrelinkedReference].
  */
 enum PrelinkedReferenceKind {
   /**
    * The entity is a class or enum.
    */
@@ skipping 289 matching lines @@
  * Unlinked summary of an entire library.
  */
 class UnlinkedLibrary {
   /**
    * Top level and prefixed names referred to by this library.
    */
   List<UnlinkedReference> references;
 
   /**
    * Information about the units constituting this library.  The first unit
-   * listed is always the defining compilation unit.
+   * listed is always the defining compilation unit.  The remaining units are
+   * listed in the order of their corresponding `part` declarations.
    */
   List<UnlinkedUnit> units;
 
   /**
    * Name of the library (from a "library" declaration, if present).
    */
   String name;
 
   /**
    * Classes declared in the library.
@@ skipping 267 matching lines @@
   /**
    * Indicates whether the variable is declared using the `final` keyword.
    */
   bool isFinal;
 
   /**
    * Indicates whether the variable is declared using the `const` keyword.
    */
   bool isConst;
 }