What is :-) ?

[Paul Backus]

On Monday, 20 November 2023 at 08:47:34 UTC, Antonio wrote:
> I understand the problem with UFCS (``next`` is not using UFCS 
> because it is a delegate defined in the own main() function,  
> and ``Counter``` without () is treated as a function call 
> because it is UFCS eligible )

This is not UFCS, it's [optional parentheses][1], which is a 
separate language feature. (Reminder: UFCS only applies when the 
callee has the form `x.y`)

According to the spec, it's disabled for function pointers and 
delegates due to the potential for ambiguity.

[1]: https://dlang.org/spec/function.html#optional-parenthesis