From 19f511fe942a7cb07a134e26afd2a95f9831693a Mon Sep 17 00:00:00 2001
From: Ryan Tjoa <rtjoa@janestreet.com>
Date: Thu, 26 Dec 2024 18:51:12 -0500
Subject: [PATCH] Inline Ctype.path_and_expansion

---
 typing/ctype.ml    |  9 ---------
 typing/ctype.mli   |  3 ---
 typing/typedecl.ml | 14 ++++++++++----
 3 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/typing/ctype.ml b/typing/ctype.ml
index c36922329f0..547b8f2d62c 100644
--- a/typing/ctype.ml
+++ b/typing/ctype.ml
@@ -2073,15 +2073,6 @@ let try_expand_safe_opt env ty =
   with Escape _ ->
     Btype.backtrack snap; raise Cannot_expand
 
-let path_and_expansion env ty =
-  match try_expand_safe_opt env ty with
-  | ty' ->
-    begin match get_desc ty with
-    | Tconstr (path, _, _) -> Some (path, ty')
-    | _ -> Misc.fatal_error "Ctype.path_and_expansion"
-    end
-  | exception Cannot_expand -> None
-
 let expand_head_opt env ty =
   try try_expand_head try_expand_safe_opt env ty with Cannot_expand -> ty
 
diff --git a/typing/ctype.mli b/typing/ctype.mli
index 8f2eefd6c93..a5d3460cdd8 100644
--- a/typing/ctype.mli
+++ b/typing/ctype.mli
@@ -246,9 +246,6 @@ val apply:
 val try_expand_once_opt: Env.t -> type_expr -> type_expr
 val try_expand_safe_opt: Env.t -> type_expr -> type_expr
 
-val path_and_expansion: Env.t -> type_expr -> (Path.t * type_expr) option
-(** Return an option instead of raising, and gives the path of the input type *)
-
 val expand_head_once: Env.t -> type_expr -> type_expr
 val expand_head: Env.t -> type_expr -> type_expr
 val expand_head_opt: Env.t -> type_expr -> type_expr
diff --git a/typing/typedecl.ml b/typing/typedecl.ml
index 04c66f2c7cb..f597c65f5ba 100644
--- a/typing/typedecl.ml
+++ b/typing/typedecl.ml
@@ -2093,10 +2093,16 @@ let check_unboxed_recursion ~abs_env env loc path0 ty0 to_check =
     | _ -> ()
   in
   let rec expand parents trace ty =
-    match Ctype.path_and_expansion env ty with
-    | Some (path, ty') ->
-      expand (Path.Set.add path parents) (Expands_to (ty, ty') :: trace) ty'
-    | None ->
+    match Ctype.try_expand_safe_opt env ty with
+    | ty' ->
+      begin match get_desc ty with
+      | Tconstr (path, _, _) ->
+        expand (Path.Set.add path parents) (Expands_to (ty, ty') :: trace) ty'
+      | _ ->
+        (* Only [Tconstr]s can be expanded *)
+        Misc.fatal_error "Typedecl.check_unboxed_recursion"
+      end
+    | exception Ctype.Cannot_expand ->
       parents, trace, ty
   in
   let rec visit parents trace ty =