Fix order of mixin application during class finalization

runtime/vm/class_finalizer.cc

 // Copyright (c) 2013, 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.
 
 #include "vm/class_finalizer.h"
 
 #include "vm/flags.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/longjump.h"
@@ skipping 1197 matching lines @@
     const Script& script = Script::Handle(cls.script());
     ReportError(script, cls.token_pos(),
                 "class '%s' has a cycle in its superclass relationship",
                 name.ToCString());
   }
   // Finalize super class.
   const Class& super_class = Class::Handle(cls.SuperClass());
   if (!super_class.IsNull()) {
     FinalizeClass(super_class);
   }
+  if (cls.mixin() != Type::null()) {
+    // Copy instance methods and fields from the mixin class.
+    // This has to happen before the check whether the methods of
+    // the class conflict with inherited methods.
+    ApplyMixin(cls);
+  }
   // Finalize type parameters before finalizing the super type.
   FinalizeTypeParameters(cls);
   // Finalize super type.
   Type& super_type = Type::Handle(cls.super_type());
   if (!super_type.IsNull()) {
     super_type ^= FinalizeType(cls, super_type, kCanonicalizeWellFormed);
     cls.set_super_type(super_type);
   }
   if (cls.IsSignatureClass()) {
     // Check for illegal self references.
@@ skipping 13 matching lines @@
     // Resolve and finalize the result and parameter types of the signature
     // function of this signature class.
     const Function& sig_function = Function::Handle(cls.signature_function());
     ResolveAndFinalizeSignature(cls, sig_function);
 
     // Resolve and finalize the signature type of this signature class.
     const Type& sig_type = Type::Handle(cls.SignatureType());
     FinalizeType(cls, sig_type, kCanonicalizeWellFormed);
     return;
   }
-  if (cls.mixin() != Type::null()) {
-    // Copy instance methods and fields from the mixin class.
-    // This has to happen before the check whether the methods of
-    // the class conflict with inherited methods.
-    ApplyMixin(cls);
-  }
   // Finalize interface types (but not necessarily interface classes).
   Array& interface_types = Array::Handle(cls.interfaces());
   AbstractType& interface_type = AbstractType::Handle();
   for (intptr_t i = 0; i < interface_types.Length(); i++) {
     interface_type ^= interface_types.At(i);
     interface_type = FinalizeType(cls, interface_type, kCanonicalizeWellFormed);
     interface_types.SetAt(i, interface_type);
   }
   // Mark as finalized before resolving type parameter upper bounds and member
   // types in order to break cycles.
@@ skipping 425 matching lines @@
 void ClassFinalizer::ReportError(const char* format, ...) {
   va_list args;
   va_start(args, format);
   const Error& error = Error::Handle(
       Parser::FormatError(Script::Handle(), -1, "Error", format, args));
   va_end(args);
   ReportError(error);
 }
 
 }  // namespace dart