Issue 24487. Annotations with constructor resolution should produce navigation reginos to construct…

pkg/analysis_server/lib/src/domains/analysis/navigation_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 domains.analysis.navigation_dart;
 
 import 'package:analysis_server/analysis/navigation_core.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
@@ skipping 56 matching lines @@
     collector.addRegion(offset, length, kind, location);
   }
 
   void _addRegion_nodeStart_nodeEnd(AstNode a, AstNode b, Element element) {
     int offset = a.offset;
     int length = b.end - offset;
     _addRegion(offset, length, element);
   }
 
   void _addRegionForNode(AstNode node, Element element) {
+    if (node == null) {
+      return;
+    }
     int offset = node.offset;
     int length = node.length;
     _addRegion(offset, length, element);
   }
 
   void _addRegionForToken(Token token, Element element) {
     int offset = token.offset;
     int length = token.length;
     _addRegion(offset, length, element);
   }
 }
 
 class _DartNavigationComputerVisitor extends RecursiveAstVisitor {
   final _DartNavigationCollector computer;
 
   _DartNavigationComputerVisitor(this.computer);
 
   @override
+  visitAnnotation(Annotation node) {
+    Element element = node.element;
+    if (element is ConstructorElement && element.isSynthetic) {
+      element = element.enclosingElement;
+    }
+    Identifier name = node.name;
+    if (name is PrefixedIdentifier) {
+      // use constructor in: @PrefixClass.constructorName
+      Element prefixElement = name.prefix.staticElement;
+      if (prefixElement is ClassElement) {
+        prefixElement = element;
+      }
+      computer._addRegionForNode(name.prefix, prefixElement);
+      // always constructor
+      computer._addRegionForNode(name.identifier, element);
+    } else {
+      computer._addRegionForNode(name, element);
+    }
+    computer._addRegionForNode(node.constructorName, element);
+    // arguments
+    _safelyVisit(node.arguments);
+  }
+
+  @override
   visitAssignmentExpression(AssignmentExpression node) {
     _safelyVisit(node.leftHandSide);
     computer._addRegionForToken(node.operator, node.bestElement);
     _safelyVisit(node.rightHandSide);
   }
 
   @override
   visitBinaryExpression(BinaryExpression node) {
     _safelyVisit(node.leftOperand);
     computer._addRegionForToken(node.operator, node.bestElement);
@@ skipping 195 matching lines @@
     }
     // The node starts or ends in the range.
     if (isInRange(node.offset) || isInRange(node.end)) {
       node.accept(visitor);
       return;
     }
     // Go deeper.
     super.visitNode(node);
   }
 }