Follow ClassTypeAlias constructor redirections.

pkg/analyzer/test/src/summary/index_unit_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.
 
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
@@ skipping 415 matching lines @@
   }
 
   void test_isReferencedBy_ConstructorElement_classTypeAlias() {
     _indexTestUnit('''
 class M {}
 class A implements B {
   A() {}
   A.named() {}
 }
 class B = A with M;
+class C = B with M;
 main() {
-  new B(); // 1
-  new B.named(); // 2
+  new B(); // B1
+  new B.named(); // B2
+  new C(); // C1
+  new C.named(); // C2
 }
 ''');
     ClassElement classA = findElement('A');
     ConstructorElement constA = classA.constructors[0];
     ConstructorElement constA_named = classA.constructors[1];
-    assertThat(constA).isReferencedAt('(); // 1', length: 0);
-    assertThat(constA_named).isReferencedAt('.named(); // 2', length: 6);
+    assertThat(constA)
+      ..isReferencedAt('(); // B1', length: 0)
+      ..isReferencedAt('(); // C1', length: 0);
+    assertThat(constA_named)
+      ..isReferencedAt('.named(); // B2', length: 6)
+      ..isReferencedAt('.named(); // C2', length: 6);
+  }
+
+  void test_isReferencedBy_ConstructorElement_classTypeAlias_cycle() {
+    _indexTestUnit('''
+class M {}
+class A = B with M;
+class B = A with M;
+main() {
+  new A();
+  new B();
+}
+''');
+    // No additional validation, but it should not fail with stack overflow.
   }
 
   void test_isReferencedBy_ConstructorElement_redirection() {
     _indexTestUnit('''
 class A {
   A() : this.bar(); // 1
   A.foo() : this(); // 2
   A.bar();
 }
 ''');
@@ skipping 308 matching lines @@
         test._expectedLocation(search, length: length));
   }
 
   void isReferencedQualifiedAt(String search, {int length}) {
     test._assertHasRelation(
         element,
         IndexRelationKind.IS_REFERENCED_QUALIFIED_BY,
         test._expectedLocation(search, length: length));
   }
 }