Remove support for interfaces.

runtime/vm/class_finalizer.cc

 // Copyright (c) 2012, 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 301 matching lines @@
   if (cls.is_finalized()) {
     return;
   }
   Type& super_type = Type::Handle(cls.super_type());
   if (super_type.IsNull()) {
     return;
   }
   // Resolve failures lead to a longjmp.
   ResolveType(cls, super_type, kCanonicalizeWellFormed);
   const Class& super_class = Class::Handle(super_type.type_class());
-  if (cls.is_interface() != super_class.is_interface()) {
-    String& class_name = String::Handle(cls.Name());
-    String& super_class_name = String::Handle(super_class.Name());
-    const Script& script = Script::Handle(cls.script());
-    ReportError(script, cls.token_pos(),
-                "class '%s' and superclass '%s' are not "
-                "both classes or both interfaces",
-                class_name.ToCString(),
-                super_class_name.ToCString());
-  }
   // If cls belongs to core lib or to core lib's implementation, restrictions
   // about allowed interfaces are lifted.
   if (cls.library() != Library::CoreLibrary()) {
     // Prevent extending core implementation classes.
     bool is_error = false;
     switch (super_class.id()) {
       case kNumberCid:
       case kIntegerCid:
       case kSmiCid:
       case kMintCid:
@@ skipping 793 matching lines @@
       for (int i = 0; i < interfaces.Length(); i++) {
         super_class ^= interfaces.At(i);
         overridden_function = super_class.LookupDynamicFunction(function_name);
         if (!overridden_function.IsNull() &&
             !function.HasCompatibleParametersWith(overridden_function)) {
           // Function types are purposely not checked for subtyping.
           const String& class_name = String::Handle(cls.Name());
           const String& super_class_name = String::Handle(super_class.Name());
           const Script& script = Script::Handle(cls.script());
           ReportError(script, function.token_pos(),
-                      "class '%s' overrides function '%s' of %s '%s' "
+                      "class '%s' overrides function '%s' of super class '%s' "
                       "with incompatible parameters",
                       class_name.ToCString(),
                       function_name.ToCString(),
-                      super_class.is_interface() ? "interface" : "super class",
                       super_class_name.ToCString());
         }
       }
     }
     if (function.IsGetterFunction()) {
       name = Field::NameFromGetter(function_name);
       super_class = FindSuperOwnerOfFunction(cls, name);
       if (!super_class.IsNull()) {
         const String& class_name = String::Handle(cls.Name());
         const String& super_class_name = String::Handle(super_class.Name());
@@ skipping 280 matching lines @@
                   "const class '%s' has non-final field '%s'",
                   class_name.ToCString(), field_name.ToCString());
     }
   }
 }
 
 
 void ClassFinalizer::PrintClassInformation(const Class& cls) {
   HANDLESCOPE(Isolate::Current());
   const String& class_name = String::Handle(cls.Name());
-  OS::Print("%s '%s'",
-            cls.is_interface() ? "interface" : "class",
-            class_name.ToCString());
+  OS::Print("class '%s'", class_name.ToCString());
   const Library& library = Library::Handle(cls.library());
   if (!library.IsNull()) {
     OS::Print(" library '%s%s':\n",
               String::Handle(library.url()).ToCString(),
               String::Handle(library.private_key()).ToCString());
   } else {
     OS::Print(" (null library):\n");
   }
   const Type& super_type = Type::Handle(cls.super_type());
   if (super_type.IsNull()) {
@@ skipping 129 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