2 files changed, 45 insertions, 0 deletions
diff --git a/tests/ui/traits/next-solver/normalize/eager-norm-pre-normalizes-to.rs b/tests/ui/traits/next-solver/normalize/eager-norm-pre-normalizes-to.rs
new file mode 100644
index 00000000000..ea18ac54c05
--- /dev/null
+++ b/tests/ui/traits/next-solver/normalize/eager-norm-pre-normalizes-to.rs
@@ -0,0 +1,44 @@
+//@ check-pass
+//@ compile-flags: -Znext-solver
+
+// A regression test for trait-system-refactor-initiative#184.
+//
+// When adding nested goals we replace aliases with infer vars
+// and add `AliasRelate` goals to constrain them. When doing this
+// for `NormalizesTo` goals, we then first tries to prove the
+// `NormalizesTo` goal and then normalized the nested aliases.
+
+trait Trait<T> {
+    type Assoc;
+}
+impl<T, U> Trait<U> for T {
+    type Assoc = ();
+}
+
+trait Id {
+    type This;
+}
+impl<T> Id for T {
+    type This = T;
+}
+trait Relate<T> {
+    type Alias;
+}
+impl<T, U> Relate<U> for T {
+    type Alias = <T as Trait<<U as Id>::This>>::Assoc;
+}
+
+
+fn guide_me<T: Trait<u32>>() {
+    // Normalizing `<T as Relate<i32>>::Alias` relates the associated type with an unconstrained
+    // term. This resulted in a `NormalizesTo(<T as Trait<<U as Id>::This>>::Assoc, ?x)` goal.
+    // We replace `<i32 as Id>::This` with an infer var `?y`, resulting in the following goals:
+    // - `NormalizesTo(<T as Trait<?y>::Assoc, ?x)`
+    // - `AliasRelate(<i32 as Id>::This, ?y)`
+    //
+    // When proving the `NormalizesTo` goal first, we incompletely constrain `?y` to `u32`,
+    // causing an unexpected type mismatch.
+    let _: <T as Relate<i32>>::Alias;
+}
+
+fn main() {}
diff --git a/tests/ui/traits/next-solver/normalize/normalize-allow-too-many-vars.rs b/tests/ui/traits/next-solver/normalize/normalize-allow-too-many-vars.rs
index 5284220ac38..3150d9a88d0 100644
--- a/tests/ui/traits/next-solver/normalize/normalize-allow-too-many-vars.rs
+++ b/tests/ui/traits/next-solver/normalize/normalize-allow-too-many-vars.rs
@@ -1,4 +1,5 @@
 //@ check-pass
+//@ compile-flags: -Znext-solver
 
 // When canonicalizing a response in the trait solver, we bail with overflow
 // if there are too many non-region inference variables. Doing so in normalizes-to