From 4308ca649fcdf2a87bad6831450f230805cbd61e Mon Sep 17 00:00:00 2001
From: Josh Berdine <jjb@fb.com>
Date: Thu, 9 Jul 2020 07:43:45 -0700
Subject: [PATCH] [sledge] Remove unnecessary hash functions

Reviewed By: ngorogiannis

Differential Revision: D22170519

fbshipit-source-id: 2c916272a
---
 sledge/src/fol.mli      |  5 ++---
 sledge/src/ses/term.ml  | 22 ++++++----------------
 sledge/src/ses/term.mli | 19 ++++++++-----------
 3 files changed, 16 insertions(+), 30 deletions(-)

diff --git a/sledge/src/fol.mli b/sledge/src/fol.mli
index f3d95cdd3..11a20c71b 100644
--- a/sledge/src/fol.mli
+++ b/sledge/src/fol.mli
@@ -7,7 +7,7 @@
 
 (** Variables *)
 module Var : sig
-  type t [@@deriving compare, equal, hash, sexp]
+  type t [@@deriving compare, equal, sexp]
   type strength = t -> [`Universal | `Existential | `Anonymous] option
 
   val pp : t pp
@@ -17,7 +17,6 @@ module Var : sig
   module Set : sig
     include NS.Set.S with type elt := t
 
-    val hash_fold_t : t Hash.folder
     val sexp_of_t : t -> Sexp.t
     val t_of_sexp : Sexp.t -> t
     val ppx : strength -> t pp
@@ -58,7 +57,7 @@ end
 
 (** Terms *)
 module Term : sig
-  type t [@@deriving compare, equal, hash, sexp]
+  type t [@@deriving compare, equal, sexp]
 
   val ppx : Var.strength -> t pp
   val pp : t pp
diff --git a/sledge/src/ses/term.ml b/sledge/src/ses/term.ml
index 66ad524a8..f19f45ca3 100644
--- a/sledge/src/ses/term.ml
+++ b/sledge/src/ses/term.ml
@@ -40,35 +40,25 @@ type opN = Concat | Record [@@deriving compare, equal, hash, sexp]
 module rec Set : sig
   include NS.Set.S with type elt := T.t
 
-  val hash : t -> int
-  val hash_fold_t : t Hash.folder
   val t_of_sexp : Sexp.t -> t
 end = struct
   include NS.Set.Make (T)
-
-  let hash_fold_t = hash_fold_t T.hash_fold_t
-  let hash = Hash.of_fold hash_fold_t
-
   include Provide_of_sexp (T)
 end
 
 and Qset : sig
   include NS.Qset.S with type elt := T.t
 
-  val hash : t -> int
-  val hash_fold_t : t Hash.folder
   val t_of_sexp : Sexp.t -> t
 end = struct
   include NS.Qset.Make (T)
 
-  let hash_fold_t = hash_fold_t T.hash_fold_t
-  let hash = Hash.of_fold hash_fold_t
   let t_of_sexp = t_of_sexp T.t_of_sexp
 end
 
 and T : sig
-  type set = Set.t [@@deriving compare, equal, hash, sexp]
-  type qset = Qset.t [@@deriving compare, equal, hash, sexp]
+  type set = Set.t [@@deriving compare, equal, sexp]
+  type qset = Qset.t [@@deriving compare, equal, sexp]
 
   type t =
     | Var of {id: int; name: string}
@@ -85,10 +75,10 @@ and T : sig
     | Integer of {data: Z.t}
     | Rational of {data: Q.t}
     | RecRecord of int
-  [@@deriving compare, equal, hash, sexp]
+  [@@deriving compare, equal, sexp]
 end = struct
-  type set = Set.t [@@deriving compare, equal, hash, sexp]
-  type qset = Qset.t [@@deriving compare, equal, hash, sexp]
+  type set = Set.t [@@deriving compare, equal, sexp]
+  type qset = Qset.t [@@deriving compare, equal, sexp]
 
   type t =
     | Var of {id: int; name: string}
@@ -105,7 +95,7 @@ end = struct
     | Integer of {data: Z.t}
     | Rational of {data: Q.t}
     | RecRecord of int
-  [@@deriving compare, equal, hash, sexp]
+  [@@deriving compare, equal, sexp]
 
   (* Note: solve (and invariant) requires Qset.min_elt to return a
      non-coefficient, so Integer and Rational terms must compare higher than
diff --git a/sledge/src/ses/term.mli b/sledge/src/ses/term.mli
index 017e85605..445927e47 100644
--- a/sledge/src/ses/term.mli
+++ b/sledge/src/ses/term.mli
@@ -26,7 +26,7 @@ type op1 =
           [Integer] types. *)
   | Splat  (** Iterated concatenation of a single byte *)
   | Select of int  (** Select an index from a record *)
-[@@deriving compare, equal, hash, sexp]
+[@@deriving compare, equal, sexp]
 
 type op2 =
   | Eq  (** Equal test *)
@@ -45,36 +45,34 @@ type op2 =
   | Ashr  (** Arithmetic shift right, bitwise *)
   | Sized  (** Size-tagged sequence *)
   | Update of int  (** Constant record with updated index *)
-[@@deriving compare, equal, hash, sexp]
+[@@deriving compare, equal, sexp]
 
 type op3 =
   | Conditional  (** If-then-else *)
   | Extract  (** Extract a slice of an sequence value *)
-[@@deriving compare, equal, hash, sexp]
+[@@deriving compare, equal, sexp]
 
 type opN =
   | Concat  (** Byte-array concatenation *)
   | Record  (** Record (array / struct) constant *)
-[@@deriving compare, equal, hash, sexp]
+[@@deriving compare, equal, sexp]
 
 module rec Set : sig
   include NS.Set.S with type elt := T.t
 
-  val hash_fold_t : t Hash.folder
   val t_of_sexp : Sexp.t -> t
 end
 
 and Qset : sig
   include NS.Qset.S with type elt := T.t
 
-  val hash_fold_t : t Hash.folder
   val t_of_sexp : Sexp.t -> t
 end
 
 and T : sig
-  type set = Set.t [@@deriving compare, equal, hash, sexp]
+  type set = Set.t [@@deriving compare, equal, sexp]
 
-  type qset = Qset.t [@@deriving compare, equal, hash, sexp]
+  type qset = Qset.t [@@deriving compare, equal, sexp]
 
   and t = private
     | Var of {id: int; name: string}
@@ -93,7 +91,7 @@ and T : sig
     | Integer of {data: Z.t}  (** Integer constant *)
     | Rational of {data: Q.t}  (** Rational constant *)
     | RecRecord of int  (** Reference to ancestor recursive record *)
-  [@@deriving compare, equal, hash, sexp]
+  [@@deriving compare, equal, sexp]
 end
 
 include module type of T with type t = T.t
@@ -101,7 +99,7 @@ include module type of T with type t = T.t
 (** Term.Var is re-exported as Var *)
 module Var : sig
   type term := t
-  type t = private term [@@deriving compare, equal, hash, sexp]
+  type t = private term [@@deriving compare, equal, sexp]
   type strength = t -> [`Universal | `Existential | `Anonymous] option
 
   module Map : Map.S with type key := t
@@ -109,7 +107,6 @@ module Var : sig
   module Set : sig
     include NS.Set.S with type elt := t
 
-    val hash_fold_t : t Hash.folder
     val sexp_of_t : t -> Sexp.t
     val t_of_sexp : Sexp.t -> t
     val ppx : strength -> t pp