public InterfaceDeclaration(TypeContainer parent, MemberName name, Modifiers mod, VSharpAttributes attrs, Location l, CompilationSourceFile file)
     : base(parent, mod, AllowedModifiers, name, attrs, l, TypeKind.Interface, file)
 {
     mod_flags |= Modifiers.ABSTRACT;
 }
 public EventFieldDeclaration(TypeContainer parent, FullNamedExpression type, Modifiers mod_flags, MemberName name, VSharpAttributes attrs)
     : base(parent, type, mod_flags, name, attrs, true)
 {
 }