1 files changed, 16 insertions, 0 deletions
diff --git a/tests/ui/type-alias-impl-trait/broken_mir.rs b/tests/ui/type-alias-impl-trait/broken_mir.rs
new file mode 100644
index 00000000000..b68e798fb7c
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/broken_mir.rs
@@ -0,0 +1,16 @@
+//! ICE: https://github.com/rust-lang/rust/issues/114121
+//! This test checks that MIR validation never constrains
+//! new hidden types that *differ* from the actual hidden types.
+//! This test used to ICE because oli-obk assumed mir validation
+//! was only ever run after opaque types were revealed in MIR.
+
+// compile-flags: -Zvalidate-mir
+// check-pass
+
+fn main() {
+    let _ = Some(()).into_iter().flat_map(|_| Some(()).into_iter().flat_map(func));
+}
+
+fn func(_: ()) -> impl Iterator<Item = ()> {
+    Some(()).into_iter().flat_map(|_| vec![])
+}