1 files changed, 29 insertions, 0 deletions
diff --git a/tests/ui/traits/new-solver/alias_eq_cant_be_furthur_normalized.rs b/tests/ui/traits/new-solver/alias_eq_cant_be_furthur_normalized.rs
new file mode 100644
index 000000000..dc726ba51
--- /dev/null
+++ b/tests/ui/traits/new-solver/alias_eq_cant_be_furthur_normalized.rs
@@ -0,0 +1,29 @@
+// check-pass
+// compile-flags: -Ztrait-solver=next
+
+// check that a goal such as `alias-eq(<T as TraitB>::Assoc<bool>, <T as TraitB>::Assoc<?0>)`
+// succeeds with a constraint that `?0 = bool`
+
+// FIXME(deferred_projection_equality): add a test that this is true during coherence
+
+trait TraitA {}
+
+trait TraitB {
+    type Assoc<T: ?Sized>;
+}
+
+impl<T: TraitB> TraitA for (T, T::Assoc<bool>) {}
+
+impl TraitB for i32 {
+    type Assoc<T: ?Sized> = u32;
+}
+
+fn needs_a<T: TraitA>() {}
+
+fn bar<T: TraitB>() {
+    needs_a::<(T, <T as TraitB>::Assoc<_>)>();
+}
+
+fn main() {
+    bar::<i32>();
+}