privacy: Fix an ICE in `path_is_private_type`
privacy: Fix an ICE in `path_is_private_type`

Fixes https://github.com/rust-lang/rust/issues/52879

(Untested.)
graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,GBGamer/rust,graydon/rust,GBGamer/rust