Improve search for constructors and import elements.

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 556 matching lines @@
     if (node.constructorName != null) {
       int offset = node.period.offset;
       int length = node.constructorName.end - offset;
       recordRelationOffset(
           element, IndexRelationKind.IS_REFERENCED_BY, offset, length, true);
     } else {
       int offset = node.superKeyword.end;
       recordRelationOffset(
           element, IndexRelationKind.IS_REFERENCED_BY, offset, 0, true);
     }
-    super.visitSuperConstructorInvocation(node);
+    node.argumentList?.accept(this);
   }
 
   @override
   visitTypeName(TypeName node) {
     AstNode parent = node.parent;
     if (parent is ClassTypeAlias && parent.superclass == node) {
       recordSuperType(node, IndexRelationKind.IS_EXTENDED_BY);
     } else {
       super.visitTypeName(node);
     }
@@ skipping 168 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));
   }
 }