[Pitch] Opaque parameter types

[gwendal.roue (Gwendal Roué)]

Thank you Doug! It may be time to quote myself:

@gwendal.roue

[...] the Motivation section of the Rust RFC that accepts impl Trait (more or less our some P ) as an argument (after it was already used as a return type), is really well written. The critique rebuttals are quite interesting as well.