1 files changed, 0 insertions, 59 deletions
diff --git a/src/test/ui/traits/reservation-impl/non-lattice-ok.rs b/src/test/ui/traits/reservation-impl/non-lattice-ok.rs
deleted file mode 100644
index a71051243c8..00000000000
--- a/src/test/ui/traits/reservation-impl/non-lattice-ok.rs
+++ /dev/null
@@ -1,59 +0,0 @@
-// build-pass
-
-// Check that a reservation impl does not force other impls to follow
-// a lattice discipline.
-
-// Why did we ever want to do this?
-//
-// We want to eventually add an `impl<T> From<!> for T` impl. That impl conflicts
-// with existing impls - at least the `impl<T> From<T> for T` impl. There are
-// 2 ways we thought of for dealing with that conflict:
-//
-// 1. Using specialization and doing some handling for the
-// overlap. The current thought is to require ["intersection
-// impls"][ii], specialization", which means providing an
-// (higher-priority) impl for the intersection of every 2 conflicting
-// impls that determines what happens in the intersection case. That's
-// the first thing we thought about - see e.g.
-// https://github.com/rust-lang/rust/issues/57012#issuecomment-452150775
-//
-// 2. The other way is to notice that `impl From<!> for T` is basically a
-// marker trait since its only method is uninhabited, and allow for "marker
-// trait overlap", where the conflict "doesn't matter" because it can't
-// actually cause any ambiguity.
-//
-// Now it turned out lattice specialization doesn't work it, because an
-// `impl<T> From<T> for Smaht<T>` would require an `impl From<!> for Smaht<!>`,
-// breaking backwards-compatibility in a fairly painful way. So if we want to
-// go with a known approach, we should go with a "marker trait overlap"-style
-// approach.
-//
-// [ii]: https://smallcultfollowing.com/babysteps/blog/2016/09/24/intersection-impls/
-
-#![feature(rustc_attrs, never_type)]
-
-trait MyTrait {}
-
-impl MyTrait for ! {}
-
-trait MyFrom<T> {
-    fn my_from(x: T) -> Self;
-}
-
-// Given the "normal" impls for From
-#[rustc_reservation_impl="this impl is reserved"]
-impl<T> MyFrom<!> for T {
-    fn my_from(x: !) -> Self { match x {} }
-}
-
-impl<T> MyFrom<T> for T {
-    fn my_from(x: T) -> Self { x }
-}
-
-// ... we *do* want to allow this common pattern, of `From<!> for MySmaht<T>`
-struct MySmaht<T>(T);
-impl<T> MyFrom<T> for MySmaht<T> {
-    fn my_from(x: T) -> Self { MySmaht(x) }
-}
-
-fn main() {}