Compute values of elements a unit constant expressions depend on.

pkg/analyzer/lib/src/generated/constant.dart

 // Copyright (c) 2014, 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.
 
 library analyzer.src.generated.constant;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 1212 matching lines @@
         errorReporter));
     if (result != null) {
       return EvaluationResult.forValue(result);
     }
     return EvaluationResult.forErrors(errorListener.errors);
   }
 }
 
 /**
  * A visitor used to traverse the AST structures of all of the compilation units
+ * being resolved and build the full set of dependencies for all constant
+ * expressions.
+ */
+class ConstantExpressionsDependenciesFinder extends RecursiveAstVisitor {
+  /**
+   * The constants whose values need to be computed.
+   */
+  HashSet<ConstantEvaluationTarget> dependencies =
+      new HashSet<ConstantEvaluationTarget>();
+
+  @override
+  void visitListLiteral(ListLiteral node) {
+    if (node.constKeyword != null) {
+      _find(node);
+    } else {
+      super.visitListLiteral(node);
+    }
+  }
+
+  @override
+  void visitMapLiteral(MapLiteral node) {
+    if (node.constKeyword != null) {
+      _find(node);
+    } else {
+      super.visitMapLiteral(node);
+    }
+  }
+
+  @override
+  void visitSwitchCase(SwitchCase node) {
+    _find(node.expression);
+    node.statements.accept(this);
+  }
+
+  void _find(Expression node) {
+    if (node != null) {
+      ReferenceFinder referenceFinder = new ReferenceFinder(dependencies.add);
+      node.accept(referenceFinder);
+    }
+  }
+}
+
+/**
+ * A visitor used to traverse the AST structures of all of the compilation units
  * being resolved and build tables of the constant variables, constant
  * constructors, constant constructor invocations, and annotations found in
  * those compilation units.
  */
 class ConstantFinder extends RecursiveAstVisitor<Object> {
   final AnalysisContext context;
   final Source source;
   final Source librarySource;
 
   /**
@@ skipping 4154 matching lines @@
       return BoolState.from(_element == rightElement);
     } else if (rightOperand is DynamicState) {
       return BoolState.UNKNOWN_VALUE;
     }
     return BoolState.FALSE_STATE;
   }
 
   @override
   String toString() => _element == null ? "-unknown-" : _element.name;
 }