Fix P#7395 by reverting 9a2015

testsuite/tests/typing-poly/poly.ml

@@ -1434,3 +1434,16 @@ type (+'a, -'b) foo = private int
 val f : int -> ('a, 'a) foo = <fun>
 val x : ('_a, '_a) foo = 3
 |}]
+
+(* PR#7395 *)
+type u
+type 'a t = u;;
+let c (f : u -> u) =
+ object
+   method apply: 'a. 'a t -> 'a t = fun x -> f x
+ end;;
+[%%expect{|
+type u
+type 'a t = u
+val c : (u -> u) -> < apply : 'a. 'a t -> 'a t > = <fun>
+|}]

typing/typecore.ml

@@ -3800,7 +3800,7 @@ and type_cases ?in_function env ty_arg ty_res partial_flag loc caselist =
   let rec is_var spat =
     match spat.ppat_desc with
       Ppat_any | Ppat_var _ -> true
-    | Ppat_alias (spat, _) | Ppat_constraint (spat, _) -> is_var spat
+    | Ppat_alias (spat, _) -> is_var spat
     | _ -> false in
   let needs_exhaust_check =
     match caselist with