Improve used name relations and fields indexing.

pkg/analyzer/lib/src/summary/index_unit.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.
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/member.dart';
@@ skipping 402 matching lines @@
   visitClassTypeAlias(ClassTypeAlias node) {
     recordIsAncestorOf(node.element);
     super.visitClassTypeAlias(node);
   }
 
   @override
   visitConstructorFieldInitializer(ConstructorFieldInitializer node) {
     SimpleIdentifier fieldName = node.fieldName;
     if (fieldName != null) {
       Element element = fieldName.staticElement;
-      recordRelation(
-          element, IndexRelationKind.IS_REFERENCED_BY, fieldName, true);
+      recordRelation(element, IndexRelationKind.IS_WRITTEN_BY, fieldName, true);
     }
     node.expression?.accept(this);
   }
 
   @override
   visitConstructorName(ConstructorName node) {
     ConstructorElement element = node.staticElement;
     element = _getActualConstructorElement(element);
     // record relation
     if (node.name != null) {
@@ skipping 102 matching lines @@
   visitSimpleIdentifier(SimpleIdentifier node) {
     Element element = node.bestElement;
     // name in declaration
     if (node.inDeclarationContext()) {
       recordDefinedElement(element);
       return;
     }
     // record qualified unresolved name reference
     bool isQualified = _isQualified(node);
     if (isQualified && element == null) {
-      recordNameRelation(node, IndexRelationKind.IS_REFERENCED_BY);
+      bool inGetterContext = node.inGetterContext();
+      bool inSetterContext = node.inSetterContext();
+      IndexRelationKind kind;
+      if (inGetterContext && inSetterContext) {
+        kind = IndexRelationKind.IS_READ_WRITTEN_BY;
+      } else if (inGetterContext) {
+        kind = IndexRelationKind.IS_READ_BY;
+      } else {
+        kind = IndexRelationKind.IS_WRITTEN_BY;
+      }
+      recordNameRelation(node, kind);
     }
     // this.field parameter
     if (element is FieldFormalParameterElement) {
-      recordRelation(
-          element.field, IndexRelationKind.IS_REFERENCED_BY, node, true);
+      AstNode parent = node.parent;
+      IndexRelationKind kind =
+          parent is FieldFormalParameter && parent.identifier == node
+              ? IndexRelationKind.IS_WRITTEN_BY
+              : IndexRelationKind.IS_REFERENCED_BY;
+      recordRelation(element.field, kind, node, true);
       return;
     }
     // ignore a local reference to a parameter
     if (element is ParameterElement && node.parent is! Label) {
       return;
     }
     // record specific relations
     recordRelation(
         element, IndexRelationKind.IS_REFERENCED_BY, node, isQualified);
   }
@@ skipping 193 matching lines @@
         usedNames: nameRelations.map((r) => r.nameInfo.id).toList(),
         usedNameKinds: nameRelations.map((r) => r.kind).toList(),
         usedNameOffsets: nameRelations.map((r) => r.offset).toList());
   }
 
   void defineName(String name, IndexNameKind kind, int offset) {
     _StringInfo nameInfo = pkg._getStringInfo(name);
     definedNames.add(new _DefinedNameInfo(nameInfo, kind, offset));
   }
 }