FnOnce internal compiler bug

[KalitaAlexey]

It fails to compile FnOnce impl.
Code that does not compile

#![feature(unboxed_closures)]
#![feature(core)]

struct Data {
    identifier: String,
}

impl FnOnce<u64> for Data {
    type Output = u64;

    extern "rust-call" fn call_once(self, arg: u64) -> Self::Output {
        arg
    }
}

fn main() {
}

Code that compiles

#![feature(unboxed_closures)]
#![feature(core)]

struct Data {
    identifier: String,
}

impl FnOnce<(u64,)> for Data {
    type Output = u64;

    extern "rust-call" fn call_once(self, args: (u64,)) -> Self::Output {
        args.0
    }
}

fn main() {
}

Error message is not helpful.

[apasel422]

This ICEs with error: internal compiler error: argument to function with "rust-call" ABI is neither a tuple nor unit, which is a duplicate of #22565 and #21139.