1 files changed, 40 insertions, 0 deletions
diff --git a/tests/ui/traits/new-solver/normalizes_to_ignores_unnormalizable_candidate.rs b/tests/ui/traits/new-solver/normalizes_to_ignores_unnormalizable_candidate.rs
new file mode 100644
index 000000000..46343241b
--- /dev/null
+++ b/tests/ui/traits/new-solver/normalizes_to_ignores_unnormalizable_candidate.rs
@@ -0,0 +1,40 @@
+// [no_self_infer] check-pass
+// compile-flags: -Ztrait-solver=next
+// revisions: self_infer no_self_infer
+
+// checks that the new solver is smart enough to infer `?0 = U` when solving:
+// `normalizes-to(<Vec<?0> as Trait>::Assoc, u8)`
+// with `normalizes-to(<Vec<U> as Trait>::Assoc, u8)` in the paramenv even when
+// there is a separate `Vec<T>: Trait` bound  in the paramenv.
+//
+// FIXME(-Ztrait-solver=next)
+// This could also compile for `normalizes-to(<?0 as Trait>::Assoc, u8)` but
+// we currently immediately consider a goal ambiguous if the self type is an
+// inference variable.
+
+trait Trait {
+    type Assoc;
+}
+
+fn foo<T: Trait<Assoc = u8>>(x: T) {}
+
+#[cfg(self_infer)]
+fn unconstrained<T>() -> T {
+    todo!()
+}
+
+#[cfg(no_self_infer)]
+fn unconstrained<T>() -> Vec<T> {
+    todo!()
+}
+
+fn bar<T, U>()
+where
+    Vec<T>: Trait,
+    Vec<U>: Trait<Assoc = u8>,
+{
+    foo(unconstrained())
+    //[self_infer]~^ ERROR type annotations needed
+}
+
+fn main() {}