Fix for inheriting covariance from a resynthesyzed parameter.

pkg/analyzer/test/src/summary/linker_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 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
 import 'package:analyzer/src/summary/link.dart';
 import 'package:test/test.dart';
@@ skipping 623 matching lines @@
     createLinker('import "a.dart"; var b = a;', path: '/b.dart');
     expect(
         _getVariable(linker
                 .getLibrary(linkerInputs.testDartUri)
                 .getContainedName('b'))
             .inferredType
             .toString(),
         'int');
   }
 
+  void test_inheritsCovariant_fromBundle() {
+    var bundle = createPackageBundle('''
+class X1 {}
+class X2 extends X1 {}
+class A {
+  void foo(covariant X1 x) {}
+}
+class B extends A {
+  void foo(X2 x) {}
+}
+''', path: '/a.dart');
+    addBundle('/a.ds', bundle);
+
+    // C.foo.x must inherit covariance from B.foo.x, even though it is
+    // resynthesized from the bundle.
+    createLinker('''
+import 'a.dart';
+class C extends B {
+  void foo(X2 x) {}
+}
+''');
+    LibraryElementForLink library = linker.getLibrary(linkerInputs.testDartUri);
+    library.libraryCycleForLink.ensureLinked();
+
+    ClassElementForLink_Class C = library.getContainedName('C');
+    expect(C.methods, hasLength(1));
+    MethodElementForLink foo = C.methods[0];
+    expect(foo.parameters, hasLength(1));
+    expect(foo.parameters[0].isCovariant, isTrue);
+  }
+
   void test_instantiate_param_of_param_to_bounds() {
     createLinker('''
 class C<T> {}
 class D<T extends num> {}
 final x = new C<D>();
 ''');
     LibraryElementForLink library = linker.getLibrary(linkerInputs.testDartUri);
     library.libraryCycleForLink.ensureLinked();
     PropertyAccessorElementForLink_Variable x = library.getContainedName('x');
     ParameterizedType type1 = x.returnType;
@@ skipping 306 matching lines @@
    */
   EntityRef _lookupInferredType(LinkedUnit unit, int slot) {
     for (EntityRef ref in unit.types) {
       if (ref.slot == slot) {
         return ref;
       }
     }
     return null;
   }
 }