Would like to see ref and out required for function calls

[bearophile]

Nick Treleaven:

> IMO it's only functions whose arguments are all passed by ref 
> that don't really need annotation, and these are infrequent. 
> All others stand to benefit.

For arguments that use "const ref", "in ref", "immutable ref" I 
think ref at the call site is not so important.

Bye,
bearophile