Hide host effect params from docs by oli-obk · Pull Request #116670 · rust-lang/rust (original) (raw)

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Since we're just looking for ConstKind::Param, we obviously don't hide host args like false, true or more complex const exprs (we'd need to check the corresp. ty::Generics first I think). Could you add a FIXME(effects) for this as well / extend the previous one.

I only know of one case where this currently surfaces (without using #![feature(rustc_attrs)] + #[rustc_host]). Namely, documenting the cross-crate re-export of pub fn h<T: Tr>() {} where Tr is a const trait results in pub fn h<T>() where T: Tr<true> since we currently don't elide defaulted args in cross-crate scenarios (#80379). My PR #112463 would fix this specific case but it's blocked on performance.

(This would also surface with always-const bounds if they were introduced like T: const Trait → T: Trait<false>, etc.)