UDAs grammar: @ valid?

[Bruno Medeiros via Digitalmars-d]

Someone opened an issue report for a bug in the DDT parser, it doesn't 
parse this:

template X(int Y){}
@X!3  // error here
void main(){}

And yet DMD accepts this code. Is this grammar supposed to be valid 
though? The grammar spec doesn't allow it, not that means much. I 
searched for an open grammar bug, but couldn't find one.


--
Bruno Medeiros
https://twitter.com/brunodomedeiros