rustc_arena::coldpath shouldn't be `pub`

[fogti]

rust/compiler/rustc_arena/src/lib.rs

Lines 33 to 37 in 1d517af

	#[inline(never)]
	#[cold]
	pub fn cold_path<F: FnOnce() -> R, R>(f: F) -> R {
	f()
	}

The function isn't used anywhere outside of that crate (there is a copy of that function in rustc_datastructures, which is used elsewhere). It shouldn't be pub at all because it is only used in the same file in which it is defined.

[homersimpsons]

Should not we use rustc_datastructures::cold_path instead of duplicating the function ?

[fogti]

rustc_arena currently doesn't depend on rustc_datastructures, and it would be a really heavyweight dependency. I don't think that's worth it as the function is extremely trivial.

[henryboisdequin]

@rustbot claim