Report unused elements in GenerateHintsTask.

pkg/analyzer/lib/src/task/dart.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.
 
 library analyzer.src.task.dart;
 
 import 'dart:collection';
 import 'dart:math' as math;
 
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 1718 matching lines @@
 /**
  * A task that generates [HINTS] for a unit.
  */
 class GenerateHintsTask extends SourceBasedAnalysisTask {
   /**
    * The name of the [RESOLVED_UNIT] input.
    */
   static const String UNIT_INPUT = 'UNIT_INPUT';
 
   /**
+   * The name of a list of [USED_ELEMENTS] for each library unit input.
+   */
+  static const String USED_ELEMENTS_INPUT = 'USED_ELEMENTS_INPUT';
+
+  /**
    * The task descriptor describing this kind of task.
    */
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor(
       'GenerateHintsTask', createTask, buildInputs, <ResultDescriptor>[HINTS]);
 
   GenerateHintsTask(InternalAnalysisContext context, AnalysisTarget target)
       : super(context, target);
 
   @override
   TaskDescriptor get descriptor => DESCRIPTOR;
 
   @override
   void internalPerform() {
     RecordingErrorListener errorListener = new RecordingErrorListener();
     Source source = getRequiredSource();
     ErrorReporter errorReporter = new ErrorReporter(errorListener, source);
     //
     // Prepare inputs.
     //
     CompilationUnit unit = getRequiredInput(UNIT_INPUT);
+    List<UsedElements> usedElementsList = getRequiredInput(USED_ELEMENTS_INPUT);
     CompilationUnitElement unitElement = unit.element;
     LibraryElement libraryElement = unitElement.library;
     //
-    // Use the HintGenerator to generate errors.
+    // Generate errors.
     //
     // TODO(scheglov) move collecting used imports into a separate task
 //      unit.accept(_importsVerifier);
     // Dead code analysis.
     unit.accept(new DeadCodeVerifier(errorReporter));
-    // TODO(scheglov) move collecting used elements into a separate task
-//      unit.accept(_usedElementsVisitor);
+    // Unused elements.
+    {
+      UsedElements usedElements = new UsedElements.merge(usedElementsList);
+      UnusedElementsVerifier visitor =
+          new UnusedElementsVerifier(errorListener, usedElements);
+      unitElement.accept(visitor);
+    }
     // Dart2js analysis.
     if (context.analysisOptions.dart2jsHint) {
       unit.accept(new Dart2JSVerifier(errorReporter));
     }
     // Dart best practices.
     InheritanceManager inheritanceManager =
         new InheritanceManager(libraryElement);
     TypeProvider typeProvider = context.typeProvider;
     unit.accept(new BestPracticesVerifier(errorReporter, typeProvider));
     unit.accept(new OverrideVerifier(errorReporter, inheritanceManager));
     // Find to-do comments.
     new ToDoFinder(errorReporter).findIn(unit);
     //
     // Record outputs.
     //
     outputs[HINTS] = errorListener.errors;
   }
 
   /**
    * Return a map from the names of the inputs of this kind of task to the task
    * input descriptors describing those inputs for a task with the
    * given [target].
    */
   static Map<String, TaskInput> buildInputs(LibraryUnitTarget target) {
-    return <String, TaskInput>{UNIT_INPUT: RESOLVED_UNIT.of(target)};
+    Source libSource = target.library;
+    return <String, TaskInput>{
+      UNIT_INPUT: RESOLVED_UNIT.of(target),
+      USED_ELEMENTS_INPUT: UNITS.of(libSource).toList((unit) {
+        LibraryUnitTarget target = new LibraryUnitTarget(libSource, unit);
+        return USED_ELEMENTS.of(target);
+      })
+    };
   }
 
   /**
    * Create a [GenerateHintsTask] based on the given [target] in
    * the given [context].
    */
   static GenerateHintsTask createTask(
       AnalysisContext context, AnalysisTarget target) {
     return new GenerateHintsTask(context, target);
   }
@@ skipping 708 matching lines @@
   @override
   bool moveNext() {
     if (_newSources.isEmpty) {
       return false;
     }
     currentTarget = _newSources.first;
     _newSources.remove(currentTarget);
     return true;
   }
 }