Add ICEing regression tests

Author: oli-obk

tests/ui/impl-trait/lazy_subtyping_of_opaques.rs

@@ -0,0 +1,49 @@
+use std::iter;
+
+mod either {
+    pub enum Either<L, R> {
+        Left(L),
+        Right(R),
+    }
+
+    impl<L: Iterator, R: Iterator<Item = L::Item>> Iterator for Either<L, R> {
+        type Item = L::Item;
+        fn next(&mut self) -> Option<Self::Item> {
+            todo!()
+        }
+    }
+    pub use self::Either::{Left, Right};
+}
+
+pub enum BabeConsensusLogRef<'a> {
+    NextEpochData(BabeNextEpochRef<'a>),
+    NextConfigData,
+}
+
+impl<'a> BabeConsensusLogRef<'a> {
+    pub fn scale_encoding(
+        &self,
+    ) -> impl Iterator<Item = impl AsRef<[u8]> + Clone + 'a> + Clone + 'a {
+        match self {
+            BabeConsensusLogRef::NextEpochData(digest) => either::Left(either::Left(
+                digest.scale_encoding().map(either::Left).map(either::Left),
+            )),
+            BabeConsensusLogRef::NextConfigData => either::Right(
+                iter::once(either::Right(either::Left([1])))
+                    .chain(std::iter::once([1]).map(either::Right).map(either::Right)),
+            ),
+        }
+    }
+}
+
+pub struct BabeNextEpochRef<'a>(&'a ());
+
+impl<'a> BabeNextEpochRef<'a> {
+    pub fn scale_encoding(
+        &self,
+    ) -> impl Iterator<Item = impl AsRef<[u8]> + Clone + 'a> + Clone + 'a {
+        std::iter::once([1])
+    }
+}
+
+fn main() {}

tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.rs

@@ -0,0 +1,22 @@
+#![feature(type_alias_impl_trait)]
+
+type Tait = impl FnOnce() -> ();
+
+fn reify_as_tait() -> Thunk<Tait> {
+    Thunk::new(|cont| cont)
+}
+
+struct Thunk<F>(F);
+
+impl<F> Thunk<F> {
+    fn new(f: F)
+    where
+        F: ContFn,
+    {
+        todo!();
+    }
+}
+
+trait ContFn {}
+
+impl<F: FnOnce(Tait) -> ()> ContFn for F {}