diff --git a/pkg/vm/lib/transformations/mixin_deduplication.dart b/pkg/vm/lib/transformations/mixin_deduplication.dart
index 68ade75..19375aa 100644
--- a/pkg/vm/lib/transformations/mixin_deduplication.dart
+++ b/pkg/vm/lib/transformations/mixin_deduplication.dart
@@ -76,8 +76,12 @@
     }
 
     if (c.supertype != null) {
-      _transformSupertype(c);
+      c.supertype = _transformSupertype(c.supertype, c, true);
     }
+    if (c.mixedInType != null) {
+      throw 'All mixins should be transformed already.';
+    }
+    transformSupertypeList(c.implementedTypes, this);
 
     if (!c.isAnonymousMixin) {
       return c;
@@ -97,18 +101,24 @@
     return c;
   }
 
-  void _transformSupertype(Class c) {
-    Class oldSuper = c.superclass;
-    if (oldSuper == null) {
-      return;
-    }
+  @override
+  Supertype visitSupertype(Supertype node) {
+    return _transformSupertype(node, null, false);
+  }
+
+  Supertype _transformSupertype(
+      Supertype supertype, Class cls, bool isSuperclass) {
+    Class oldSuper = supertype.classNode;
     Class newSuper = visitClass(oldSuper);
     if (newSuper == null) {
       Class canonicalSuper = _duplicatedMixins[oldSuper];
       assert(canonicalSuper != null);
-      c.supertype = new Supertype(canonicalSuper, c.supertype.typeArguments);
-      _correctForwardingConstructors(c, oldSuper, canonicalSuper);
+      supertype = new Supertype(canonicalSuper, supertype.typeArguments);
+      if (isSuperclass) {
+        _correctForwardingConstructors(cls, oldSuper, canonicalSuper);
+      }
     }
+    return supertype;
   }
 
   @override
diff --git a/tests/language_2/language_2_kernel.status b/tests/language_2/language_2_kernel.status
index 6c38373..5d8f770 100644
--- a/tests/language_2/language_2_kernel.status
+++ b/tests/language_2/language_2_kernel.status
@@ -159,7 +159,6 @@
 covariant_subtyping_test: RuntimeError
 generic_methods_generic_function_result_test/01: MissingCompileTimeError
 generic_no_such_method_dispatcher_test: RuntimeError # Issue 31424
-mixin_declaration/mixin_declaration_inference_valid_mixin_applications_test: DartkCrash
 web_int_literals_test/*: SkipByDesign # Test applies only to JavaScript targets
 
 [ $compiler == fasta ]
diff --git a/tests/language_2/mixin_deduplication_test.dart b/tests/language_2/mixin_deduplication_test.dart
new file mode 100644
index 0000000..f401bf1
--- /dev/null
+++ b/tests/language_2/mixin_deduplication_test.dart
@@ -0,0 +1,46 @@
+// Copyright (c) 2018, 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.
+
+// Test mixin de-duplication with new mixin syntax.
+
+import 'package:expect/expect.dart';
+
+class A {
+  int foo() => 1;
+}
+
+class B {
+  int bar() => 2;
+}
+
+abstract class C implements A, B {
+}
+
+mixin M1 on A, B {
+  int sum() => foo() + bar();
+}
+
+mixin M2 on A, B, M1 {
+  int sumX2() => sum()*2;
+}
+
+class X extends C with M1, M2 {
+  int foo() => 4;
+  int bar() => 5;
+}
+
+class Y extends C with M1, M2 {
+  int foo() => 7;
+  int bar() => 10;
+}
+
+X x = new X();
+Y y = new Y();
+
+void main() {
+  Expect.equals(9, x.sum());
+  Expect.equals(18, x.sumX2());
+  Expect.equals(17, y.sum());
+  Expect.equals(34, y.sumX2());
+}