Compute also constant dependencies reference in method bodies.

pkg/analyzer/lib/src/dart/analysis/analysis_impl.dart

 // Copyright (c) 2017, 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.
 
 import 'package:analyzer/context/declared_variables.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
@@ skipping 444 matching lines @@
         _libraryElement, source, _typeProvider, errorListener));
 
     //
     // Find constants to compute.
     //
     {
       ConstantFinder constantFinder = new ConstantFinder();
       unit.accept(constantFinder);
       _constants.addAll(constantFinder.constantsToCompute);
     }
+
+    //
+    // Find constant dependencies to compute.
+    //
+    {
+      var finder = new ConstantExpressionsDependenciesFinder();
+      unit.accept(finder);
+      _constants.addAll(finder.dependencies);
+    }
   }
 
   /**
    * Return the result of resolve the given [uriContent], reporting errors
    * against the [uriLiteral].
    */
   Source _resolveUri(FileState file, bool isImport, StringLiteral uriLiteral,
       String uriContent) {
     UriValidationCode code =
         UriBasedDirectiveImpl.validateUri(isImport, uriLiteral, uriContent);
@@ skipping 202 matching lines @@
 }
 
 /**
  * Either the name or the source associated with a part-of directive.
  */
 class _NameOrSource {
   final String name;
   final Source source;
   _NameOrSource(this.name, this.source);
 }