Add a test

tests/ui/traits/next-solver/normalize-region-obligations.rs

@@ -0,0 +1,22 @@
+// revisions: normalize_param_env normalize_obligation
+// check-pass
+// compile-flags: -Znext-solver
+
+trait Foo {
+    #[cfg(normalize_param_env)]
+    type Gat<'a> where <Self as Mirror>::Assoc: 'a;
+    #[cfg(normalize_obligation)]
+    type Gat<'a> where Self: 'a;
+}
+
+trait Mirror { type Assoc: ?Sized; }
+impl<T: ?Sized> Mirror for T { type Assoc = T; }
+
+impl<T> Foo for T {
+    #[cfg(normalize_param_env)]
+    type Gat<'a> = i32 where T: 'a;
+    #[cfg(normalize_obligation)]
+    type Gat<'a> = i32 where <T as Mirror>::Assoc: 'a;
+}
+
+fn main() {}