In the new task model, use explicit dependencies on the type provider.

pkg/analyzer/lib/src/task/dart.dart

Index: pkg/analyzer/lib/src/task/dart.dart
diff --git a/pkg/analyzer/lib/src/task/dart.dart b/pkg/analyzer/lib/src/task/dart.dart
index 4fc84670e22c7ca7a3f6af388c7f74b68201227f..7225ee5e275d048e4c4cccd0046ed91d8a07af6f 100644
--- a/pkg/analyzer/lib/src/task/dart.dart
+++ b/pkg/analyzer/lib/src/task/dart.dart
@@ -1680,6 +1680,11 @@ class ComputeConstantDependenciesTask extends ConstantEvaluationAnalysisTask {
    */
   static const String UNIT_INPUT = 'UNIT_INPUT';
 
+  /**
+   * The name of the [TYPE_PROVIDER] input.
+   */
+  static const String TYPE_PROVIDER_INPUT = 'TYPE_PROVIDER_INPUT';
+
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor(
       'ComputeConstantDependenciesTask', createTask, buildInputs,
       <ResultDescriptor>[CONSTANT_DEPENDENCIES]);
@@ -1702,7 +1707,7 @@ class ComputeConstantDependenciesTask extends ConstantEvaluationAnalysisTask {
     //
     ConstantEvaluationTarget constant = target;
     AnalysisContext context = constant.context;
-    TypeProvider typeProvider = context.typeProvider;
+    TypeProvider typeProvider = getRequiredInput(TYPE_PROVIDER_INPUT);
     //
     // Compute dependencies.
     //
@@ -1726,12 +1731,14 @@ class ComputeConstantDependenciesTask extends ConstantEvaluationAnalysisTask {
           .getAncestor((Element element) => element is CompilationUnitElement);
       return <String, TaskInput>{
         UNIT_INPUT: RESOLVED_UNIT6
-            .of(new LibrarySpecificUnit(unit.librarySource, target.source))
+            .of(new LibrarySpecificUnit(unit.librarySource, target.source)),
+        TYPE_PROVIDER_INPUT: TYPE_PROVIDER.of(AnalysisContextTarget.request)
       };
     } else if (target is ConstantEvaluationTarget_Annotation) {
       return <String, TaskInput>{
         UNIT_INPUT: RESOLVED_UNIT6
-            .of(new LibrarySpecificUnit(target.librarySource, target.source))
+            .of(new LibrarySpecificUnit(target.librarySource, target.source)),
+        TYPE_PROVIDER_INPUT: TYPE_PROVIDER.of(AnalysisContextTarget.request)
       };
     } else {
       // Should never happen.
@@ -1761,6 +1768,11 @@ class ComputeConstantValueTask extends ConstantEvaluationAnalysisTask {
    */
   static const String DEPENDENCIES_INPUT = 'DEPENDENCIES_INPUT';
 
+  /**
+   * The name of the [TYPE_PROVIDER] input.
+   */
+  static const String TYPE_PROVIDER_INPUT = 'TYPE_PROVIDER_INPUT';
+
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor(
       'ComputeConstantValueTask', createTask, buildInputs,
       <ResultDescriptor>[CONSTANT_VALUE]);
@@ -1782,7 +1794,7 @@ class ComputeConstantValueTask extends ConstantEvaluationAnalysisTask {
     // are computed first.
     ConstantEvaluationTarget constant = target;
     AnalysisContext context = constant.context;
-    TypeProvider typeProvider = context.typeProvider;
+    TypeProvider typeProvider = getRequiredInput(TYPE_PROVIDER_INPUT);
     //
     // Compute the value of the constant.
     //
@@ -1802,7 +1814,8 @@ class ComputeConstantValueTask extends ConstantEvaluationAnalysisTask {
   static Map<String, TaskInput> buildInputs(ConstantEvaluationTarget target) {
     return <String, TaskInput>{
       DEPENDENCIES_INPUT:
-          CONSTANT_DEPENDENCIES.of(target).toListOf(CONSTANT_VALUE)
+          CONSTANT_DEPENDENCIES.of(target).toListOf(CONSTANT_VALUE),
+      TYPE_PROVIDER_INPUT: TYPE_PROVIDER.of(AnalysisContextTarget.request)
     };
   }
 
@@ -2287,6 +2300,11 @@ class GenerateHintsTask extends SourceBasedAnalysisTask {
   static const String USED_IMPORTED_ELEMENTS_INPUT = 'USED_IMPORTED_ELEMENTS';
 
   /**
+   * The name of the [TYPE_PROVIDER] input.
+   */
+  static const String TYPE_PROVIDER_INPUT = 'TYPE_PROVIDER_INPUT';
+
+  /**
    * The task descriptor describing this kind of task.
    */
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor(
@@ -2340,7 +2358,7 @@ class GenerateHintsTask extends SourceBasedAnalysisTask {
     // Dart best practices.
     InheritanceManager inheritanceManager =
         new InheritanceManager(libraryElement);
-    TypeProvider typeProvider = context.typeProvider;
+    TypeProvider typeProvider = getRequiredInput(TYPE_PROVIDER_INPUT);
     unit.accept(new BestPracticesVerifier(errorReporter, typeProvider));
     unit.accept(new OverrideVerifier(errorReporter, inheritanceManager));
     // Find to-do comments.
@@ -2367,7 +2385,8 @@ class GenerateHintsTask extends SourceBasedAnalysisTask {
       USED_IMPORTED_ELEMENTS_INPUT: UNITS.of(libSource).toList((unit) {
         LibrarySpecificUnit target = new LibrarySpecificUnit(libSource, unit);
         return USED_IMPORTED_ELEMENTS.of(target);
-      })
+      }),
+      TYPE_PROVIDER_INPUT: TYPE_PROVIDER.of(AnalysisContextTarget.request)
     };
   }
 
@@ -2802,6 +2821,11 @@ class ResolveReferencesTask extends SourceBasedAnalysisTask {
   static const String UNIT_INPUT = 'UNIT_INPUT';
 
   /**
+   * The name of the [TYPE_PROVIDER] input.
+   */
+  static const String TYPE_PROVIDER_INPUT = 'TYPE_PROVIDER_INPUT';
+
+  /**
    * The task descriptor describing this kind of task.
    */
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor(
@@ -2825,7 +2849,7 @@ class ResolveReferencesTask extends SourceBasedAnalysisTask {
     LibraryElement libraryElement = getRequiredInput(LIBRARY_INPUT);
     CompilationUnit unit = getRequiredInput(UNIT_INPUT);
     CompilationUnitElement unitElement = unit.element;
-    TypeProvider typeProvider = unitElement.context.typeProvider;
+    TypeProvider typeProvider = getRequiredInput(TYPE_PROVIDER_INPUT);
     //
     // Resolve references.
     //
@@ -2849,7 +2873,8 @@ class ResolveReferencesTask extends SourceBasedAnalysisTask {
   static Map<String, TaskInput> buildInputs(LibrarySpecificUnit target) {
     return <String, TaskInput>{
       LIBRARY_INPUT: LIBRARY_ELEMENT.of(target.library),
-      UNIT_INPUT: RESOLVED_UNIT5.of(target)
+      UNIT_INPUT: RESOLVED_UNIT5.of(target),
+      TYPE_PROVIDER_INPUT: TYPE_PROVIDER.of(AnalysisContextTarget.request)
     };
   }
 
@@ -2873,6 +2898,11 @@ class ResolveUnitTypeNamesTask extends SourceBasedAnalysisTask {
   static const String UNIT_INPUT = 'UNIT_INPUT';
 
   /**
+   * The name of the [TYPE_PROVIDER] input.
+   */
+  static const String TYPE_PROVIDER_INPUT = 'TYPE_PROVIDER_INPUT';
+
+  /**
    * The task descriptor describing this kind of task.
    */
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor(
@@ -2896,12 +2926,12 @@ class ResolveUnitTypeNamesTask extends SourceBasedAnalysisTask {
     //
     CompilationUnit unit = getRequiredInput(UNIT_INPUT);
     CompilationUnitElement unitElement = unit.element;
+    TypeProvider typeProvider = getRequiredInput(TYPE_PROVIDER_INPUT);
     //
     // Resolve TypeName nodes.
     //
     TypeResolverVisitor visitor = new TypeResolverVisitor.con2(
-        unitElement.library, unitElement.source, context.typeProvider,
-        errorListener);
+        unitElement.library, unitElement.source, typeProvider, errorListener);
     unit.accept(visitor);
     //
     // Record outputs.
@@ -2916,7 +2946,10 @@ class ResolveUnitTypeNamesTask extends SourceBasedAnalysisTask {
    * given [target].
    */
   static Map<String, TaskInput> buildInputs(LibrarySpecificUnit target) {
-    return <String, TaskInput>{UNIT_INPUT: RESOLVED_UNIT3.of(target)};
+    return <String, TaskInput>{
+      UNIT_INPUT: RESOLVED_UNIT3.of(target),
+      TYPE_PROVIDER_INPUT: TYPE_PROVIDER.of(AnalysisContextTarget.request)
+    };
   }
 
   /**
@@ -2944,6 +2977,11 @@ class ResolveVariableReferencesTask extends SourceBasedAnalysisTask {
   static const String UNIT_INPUT = 'UNIT_INPUT';
 
   /**
+   * The name of the [TYPE_PROVIDER] input.
+   */
+  static const String TYPE_PROVIDER_INPUT = 'TYPE_PROVIDER_INPUT';
+
+  /**
    * The task descriptor describing this kind of task.
    */
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor(
@@ -2969,7 +3007,7 @@ class ResolveVariableReferencesTask extends SourceBasedAnalysisTask {
     //
     // Resolve local variables.
     //
-    TypeProvider typeProvider = unitElement.context.typeProvider;
+    TypeProvider typeProvider = getRequiredInput(TYPE_PROVIDER_INPUT);
     Scope nameScope = new LibraryScope(libraryElement, errorListener);
     AstVisitor visitor = new VariableResolverVisitor.con2(libraryElement,
         unitElement.source, typeProvider, nameScope, errorListener);
@@ -2988,7 +3026,8 @@ class ResolveVariableReferencesTask extends SourceBasedAnalysisTask {
   static Map<String, TaskInput> buildInputs(LibrarySpecificUnit target) {
     return <String, TaskInput>{
       LIBRARY_INPUT: LIBRARY_ELEMENT.of(target.library),
-      UNIT_INPUT: RESOLVED_UNIT4.of(target)
+      UNIT_INPUT: RESOLVED_UNIT4.of(target),
+      TYPE_PROVIDER_INPUT: TYPE_PROVIDER.of(AnalysisContextTarget.request)
     };
   }
 
@@ -3079,6 +3118,11 @@ class VerifyUnitTask extends SourceBasedAnalysisTask {
   static const String UNIT_INPUT = 'UNIT_INPUT';
 
   /**
+   * The name of the [TYPE_PROVIDER] input.
+   */
+  static const String TYPE_PROVIDER_INPUT = 'TYPE_PROVIDER_INPUT';
+
+  /**
    * The task descriptor describing this kind of task.
    */
   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor('VerifyUnitTask',
@@ -3100,7 +3144,7 @@ class VerifyUnitTask extends SourceBasedAnalysisTask {
     RecordingErrorListener errorListener = new RecordingErrorListener();
     Source source = getRequiredSource();
     errorReporter = new ErrorReporter(errorListener, source);
-    TypeProvider typeProvider = context.typeProvider;
+    TypeProvider typeProvider = getRequiredInput(TYPE_PROVIDER_INPUT);
     //
     // Prepare inputs.
     //
@@ -3125,7 +3169,10 @@ class VerifyUnitTask extends SourceBasedAnalysisTask {
    * given [target].
    */
   static Map<String, TaskInput> buildInputs(LibrarySpecificUnit target) {
-    return <String, TaskInput>{UNIT_INPUT: RESOLVED_UNIT.of(target)};
+    return <String, TaskInput>{
+      UNIT_INPUT: RESOLVED_UNIT.of(target),
+      TYPE_PROVIDER_INPUT: TYPE_PROVIDER.of(AnalysisContextTarget.request)
+    };
   }
 
   /**