proper jkind reason

Author: alanechang

ocaml/typing/jkind.ml

@@ -629,6 +629,8 @@ type any_creation_reason =
   | Dummy_jkind
   | Type_expression_call
   | Inside_of_Tarrow
+  | Wildcard
+  | Unification_var
 
 type float64_creation_reason = Primitive of Ident.t
 
@@ -988,6 +990,8 @@ end = struct
     | Type_expression_call ->
       fprintf ppf "a call to [type_expression] via the ocaml API"
     | Inside_of_Tarrow -> fprintf ppf "argument or result of a Tarrow"
+    | Wildcard -> fprintf ppf "a _ in a type"
+    | Unification_var -> fprintf ppf "a fresh unification variable"
 
   let format_immediate_creation_reason ppf : immediate_creation_reason -> _ =
     function
@@ -1359,6 +1363,8 @@ module Debug_printers = struct
     | Dummy_jkind -> fprintf ppf "Dummy_jkind"
     | Type_expression_call -> fprintf ppf "Type_expression_call"
     | Inside_of_Tarrow -> fprintf ppf "Inside_of_Tarrow"
+    | Wildcard -> fprintf ppf "Wildcard"
+    | Unification_var -> fprintf ppf "Unification_var"
 
   let immediate_creation_reason ppf : immediate_creation_reason -> _ = function
     | Empty_record -> fprintf ppf "Empty_record"

ocaml/typing/jkind.mli

@@ -256,6 +256,8 @@ type any_creation_reason =
        unified to correct levels *)
   | Type_expression_call
   | Inside_of_Tarrow
+  | Wildcard
+  | Unification_var
 
 type float64_creation_reason = Primitive of Ident.t
 

ocaml/typing/typetexp.ml

@@ -432,7 +432,7 @@ end = struct
 
   let new_jkind ~is_named { jkind_initialization } =
     match jkind_initialization with
-    | Any -> Jkind.any ~why:Dummy_jkind
+    | Any -> Jkind.any ~why:(if is_named then Unification_var else Wildcard)
     | Sort -> Jkind.of_new_sort ~why:(if is_named then Unification_var else Wildcard)