Custom attributes (again)

[Walter Bright]

On 4/6/2012 3:27 AM, Ary Manzana wrote:
>> @safe, @nothrow, etc., require a lot of semantic support in the
>> compiler. They cannot pretend to be user defined attributes.
>
> Yes they can. That's how it is done in C# and Java. In fact, IUnknown is
> pretending to be an interface and has semantic support in the compiler.

All the semantics of @safe are in the compiler. None of it can be user defined. 
There's just no point to trying to make it user defined. It's like trying to 
make int user defined.

IUnknown's semantics are nearly all user-defined.