opMixin or mixin function templates with convenience operator?

[jmh530]

On Thursday, 12 December 2019 at 11:39:46 UTC, Ola Fosheim 
Grøstad wrote:
> [snip]
>
> This is getting close to AST macros... but you should be able 
> to put constraint on the resulting AST.

If it is anything like AST macros, then I wouldn't expect Walter 
to be that supportive of it...