add test for Failed to normalize closure with TAIT #109020

Fixes #109020

Author: matthiaskrgr

tests/ui/type-alias-impl-trait/closure-normalization-ice-109020.rs

@@ -0,0 +1,41 @@
+// ICE Failed to normalize closure with TAIT
+// issue: rust-lang/rust#109020
+//@ check-pass
+
+#![feature(type_alias_impl_trait)]
+
+use std::marker::PhantomData;
+
+type WithEmplacableForFn<'a> = impl EmplacableFn + 'a;
+
+fn with_emplacable_for<'a, F, R>(mut f: F) -> R
+where
+    F: for<'b> FnMut(Emplacable<WithEmplacableForFn<'b>>) -> R,
+{
+    fn with_emplacable_for_inner<'a, R>(
+        _: &'a (),
+        _: &mut dyn FnMut(Emplacable<WithEmplacableForFn<'a>>) -> R,
+    ) -> R {
+        fn _constrain(_: &mut ()) -> WithEmplacableForFn<'_> {
+            ()
+        }
+        loop {}
+    }
+
+    with_emplacable_for_inner(&(), &mut f)
+}
+
+trait EmplacableFn {}
+
+impl EmplacableFn for () {}
+
+struct Emplacable<F>
+where
+    F: EmplacableFn,
+{
+    phantom: PhantomData<F>,
+}
+
+fn main() {
+    with_emplacable_for(|_| {});
+}