Improve the handling of inference for instance fields in the task model

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 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 2649 matching lines @@
   @override
   void internalPerform() {
     //
     // Prepare inputs.
     //
     // Note: DEPENDENCIES_INPUT is not needed.  It is merely a bookkeeping
     // dependency to ensure that the variables that this variable references
     // have types inferred before inferring the type of this variable.
     //
     VariableElementImpl variable = target;
+
     CompilationUnit unit = getRequiredInput(UNIT_INPUT);
     TypeProvider typeProvider = getRequiredInput(TYPE_PROVIDER_INPUT);
     RecordingErrorListener errorListener = new RecordingErrorListener();
-    if (dependencyCycle == null) {
-      //
-      // Re-resolve the variable's initializer so that the inferred types of other
-      // variables will be propagated.
-      //
-      NodeLocator locator = new NodeLocator(variable.nameOffset);
-      AstNode node = locator.searchWithin(unit);
-      VariableDeclaration declaration = node
-          .getAncestor((AstNode ancestor) => ancestor is VariableDeclaration);
-      if (declaration == null || declaration.name != node) {
-        throw new AnalysisException(
-            "NodeLocator failed to find a variable's declaration");
-      }
-      Expression initializer = declaration.initializer;
-      ResolutionEraser.erase(initializer, eraseDeclarations: false);
-      ResolutionContext resolutionContext =
-          ResolutionContextBuilder.contextFor(initializer, errorListener);
-      ResolverVisitor visitor = new ResolverVisitor(
-          variable.library, variable.source, typeProvider, errorListener,
-          nameScope: resolutionContext.scope);
-      if (resolutionContext.enclosingClassDeclaration != null) {
-        visitor.prepareToResolveMembersInClass(
-            resolutionContext.enclosingClassDeclaration);
-      }
-      visitor.initForIncrementalResolution();
-      initializer.accept(visitor);
+    VariableDeclaration declaration = getDeclaration(unit);
+    //
+    // Re-resolve the variable's initializer so that the inferred types of other
+    // variables will be propagated.
+    //
+    Expression initializer = declaration.initializer;
+    ResolutionEraser.erase(initializer, eraseDeclarations: false);
+    ResolutionContext resolutionContext =
+        ResolutionContextBuilder.contextFor(initializer, errorListener);
+    ResolverVisitor visitor = new ResolverVisitor(
+        variable.library, variable.source, typeProvider, errorListener,
+        nameScope: resolutionContext.scope);
+    if (resolutionContext.enclosingClassDeclaration != null) {
+      visitor.prepareToResolveMembersInClass(
+          resolutionContext.enclosingClassDeclaration);
+    }
+    visitor.initForIncrementalResolution();
+    initializer.accept(visitor);
+
+    // If we're not in a dependency cycle, and we have no type annotation,
+    // do inference.
+    if (dependencyCycle == null && variable.hasImplicitType) {
       //
       // Record the type of the variable.
       //
       DartType newType = initializer.staticType;
       if (newType == null || newType.isBottom) {
         newType = typeProvider.dynamicType;
       }
       variable.type = newType;
       (variable.initializer as ExecutableElementImpl).returnType = newType;
       if (variable is PropertyInducingElementImpl) {
@@ skipping 1393 matching lines @@
 
   @override
   bool moveNext() {
     if (_newSources.isEmpty) {
       return false;
     }
     currentTarget = _newSources.removeLast();
     return true;
   }
 }