Fix build

Author: Gbury

middle_end/flambda/types/structures/row_like.rec.ml

@@ -628,7 +628,7 @@ struct
           | Unknown -> Unknown
           | Known res -> Ok res
 
-    let get_variant_field t variant_tag field_index : _ Or_unknown_or_bottom.t =
+    let _get_variant_field t variant_tag field_index : _ Or_unknown_or_bottom.t =
       let index = Target_imm.to_targetint field_index in
       let aux { index = size; maps_to; } : _ Or_unknown_or_bottom.t =
         match size with

middle_end/flambda/types/structures/row_like.rec.mli

@@ -74,8 +74,10 @@ module For_blocks : sig
   *)
   val get_field : t -> Target_imm.t -> Type_grammar.t Or_unknown_or_bottom.t
 
+  (*
   val get_variant_field :
     t -> Tag.t -> Target_imm.t -> Type_grammar.t Or_unknown_or_bottom.t
+  *)
 
   val is_bottom : t -> bool