Declares a derive-like function attr macro which creates another wrap-like function with single tuple-loosened argument, retrieved from the former function.
Upon call, the loosened function propagates the call with the flattened input tuple as arguments to the original function.
``
// 'derives' a
fa_loose` wrapper-like function
fn fa(a: A, b: B) {}
fa(A, B); // normal call
let args = (A, B); fa_loose(args); // loose call // ie. instead of two arguments, there is only a single tuple argument
// another usage exaple
(0..10)
.map(|| (A, B))
.map(faloose)
.collect::
This is a draft and is my first try on proc-macros. I suggested this as an rfc before realising a proc macro would suffice: https://github.com/rust-lang/rfcs/issues/2667