Add support for accessing field formal parameters in the initializer list of constructors

pkg/analyzer/test/generated/simple_resolver_test.dart

 // Copyright (c) 2016, 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.test.generated.simple_resolver_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 638 matching lines @@
 }
 class A {
   void sort([compare = Comparable.compare]) {}
 }''');
     computeLibrarySourceErrors(source);
     assertNoErrors(source);
     verify([source]);
   }
 
   void test_fieldFormalParameter() {
+    AnalysisOptionsImpl options = new AnalysisOptionsImpl();
+    options.enableInitializingFormalAccess = true;
+    resetWithOptions(options);
     Source source = addSource(r'''
 class A {
   int x;
-  A(this.x) {}
+  int y;
+  A(this.x) : y = x {}
 }''');
+    CompilationUnit unit =
+        analysisContext2.resolveCompilationUnit2(source, source);
+    ClassDeclaration classA = unit.declarations[0];
+    FieldDeclaration field = classA.members[0];
+    ConstructorDeclaration constructor = classA.members[2];
+    ParameterElement paramElement =
+        constructor.parameters.parameters[0].element;
+    expect(paramElement, new isInstanceOf<FieldFormalParameterElement>());
+    expect((paramElement as FieldFormalParameterElement).field,
+        field.fields.variables[0].element);
+    ConstructorFieldInitializer initializer = constructor.initializers[0];
+    SimpleIdentifier identifierX = initializer.expression;
+    expect(identifierX.staticElement, paramElement);
+
     computeLibrarySourceErrors(source);
     assertNoErrors(source);
     verify([source]);
   }
 
   void test_forEachLoops_nonConflicting() {
     Source source = addSource(r'''
 f() {
   List list = [1,2,3];
   for (int x in list) {}
@@ skipping 1141 matching lines @@
         // check propagated type
         FunctionType propagatedType = node.propagatedType as FunctionType;
         expect(propagatedType.returnType, test.typeProvider.stringType);
       } on AnalysisException catch (e, stackTrace) {
         thrownException[0] = new CaughtException(e, stackTrace);
       }
     }
     return null;
   }
 }