unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/dune

@@ -0,0 +1,18 @@
+(library
+ (name ppx_sexp_conv_test_sexp_grammar)
+ (libraries base expect_test_helpers_core.expect_test_helpers_base
+   sexp_grammar)
+ (preprocess
+  (pps ppx_sexp_conv ppx_expect ppx_here)))
+
+(rule
+ (targets regular_vs_polymorphic_variants.diff)
+ (deps test_regular_variants.ml test_polymorphic_variants.ml)
+ (mode promote)
+ (action
+  (bash
+    "%{bin:patdiff-for-review} %{bin:patdiff} %{deps} > %{targets} || true")))
+
+(alias
+ (name DEFAULT)
+ (deps regular_vs_polymorphic_variants.diff))

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_allow_extra_fields.ml

@@ -0,0 +1,119 @@
+open! Base
+
+module _ = struct
+  type t = { a : int } [@@sexp.allow_extra_fields] [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (List
+               (Fields
+                  { allow_extra_fields = true
+                  ; fields =
+                      [ No_tag
+                          { name = "a"
+                          ; required = true
+                          ; args = Cons (int_sexp_grammar.untyped, Empty)
+                          }
+                      ]
+                  })))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module _ = struct
+  type t = { a : int } [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (List
+               (Fields
+                  { allow_extra_fields = false
+                  ; fields =
+                      [ No_tag
+                          { name = "a"
+                          ; required = true
+                          ; args = Cons (int_sexp_grammar.untyped, Empty)
+                          }
+                      ]
+                  })))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module _ = struct
+  type t =
+    | Allow_extra_fields of { foo : int } [@sexp.allow_extra_fields]
+    | Forbid_extra_fields of { bar : int }
+  [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (Variant
+               { case_sensitivity = Case_sensitive_except_first_character
+               ; clauses =
+                   [ No_tag
+                       { name = "Allow_extra_fields"
+                       ; clause_kind =
+                           List_clause
+                             { args =
+                                 Fields
+                                   { allow_extra_fields = true
+                                   ; fields =
+                                       [ No_tag
+                                           { name = "foo"
+                                           ; required = true
+                                           ; args = Cons (int_sexp_grammar.untyped, Empty)
+                                           }
+                                       ]
+                                   }
+                             }
+                       }
+                   ; No_tag
+                       { name = "Forbid_extra_fields"
+                       ; clause_kind =
+                           List_clause
+                             { args =
+                                 Fields
+                                   { allow_extra_fields = false
+                                   ; fields =
+                                       [ No_tag
+                                           { name = "bar"
+                                           ; required = true
+                                           ; args = Cons (int_sexp_grammar.untyped, Empty)
+                                           }
+                                       ]
+                                   }
+                             }
+                       }
+                   ]
+               }))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+
+  let _ = Allow_extra_fields { foo = 1 }
+  let _ = Forbid_extra_fields { bar = 1 }
+end

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_allow_extra_fields.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_attributes.ml

@@ -0,0 +1,117 @@
+open! Base
+
+module type S = sig
+  type t [@@deriving sexp_grammar]
+end
+
+let show_grammar (module M : S) =
+  Expect_test_helpers_base.print_s ([%sexp_of: _ Sexp_grammar.t] [%sexp_grammar: M.t])
+;;
+
+module Grammarless = struct
+  type t =
+    [ `A
+    | `B of string
+    ]
+end
+
+let the_grammar = [%sexp_grammar: [ `A | `B of string ]]
+
+let%expect_test "[@sexp_grammar.custom] in [@@deriving]" =
+  show_grammar
+    (module struct
+      type t = (Grammarless.t[@sexp_grammar.custom the_grammar]) * int
+      [@@deriving_inline sexp_grammar]
+
+      let _ = fun (_ : t) -> ()
+
+      let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+        { untyped =
+            Lazy
+              (lazy
+                (List
+                   (Cons
+                      ( (the_grammar : Grammarless.t Sexplib0.Sexp_grammar.t).untyped
+                      , Cons (int_sexp_grammar.untyped, Empty) ))))
+        }
+      ;;
+
+      let _ = t_sexp_grammar
+
+      [@@@end]
+    end);
+  [%expect
+    {|
+    (List (
+      Cons
+      (Variant (
+        (case_sensitivity Case_sensitive)
+        (clauses (
+          (No_tag (
+            (name        A)
+            (clause_kind Atom_clause)))
+          (No_tag (
+            (name B) (clause_kind (List_clause (args (Cons String Empty))))))))))
+      (Cons Integer Empty)))
+    |}]
+;;
+
+let%expect_test "[@sexp_grammar.custom] in [%sexp_grammar]" =
+  show_grammar
+    (module struct
+      type t = Grammarless.t * int
+
+      let t_sexp_grammar =
+        [%sexp_grammar: (Grammarless.t[@sexp_grammar.custom the_grammar]) * int]
+      ;;
+    end);
+  [%expect
+    {|
+    (List (
+      Cons
+      (Variant (
+        (case_sensitivity Case_sensitive)
+        (clauses (
+          (No_tag (
+            (name        A)
+            (clause_kind Atom_clause)))
+          (No_tag (
+            (name B) (clause_kind (List_clause (args (Cons String Empty))))))))))
+      (Cons Integer Empty)))
+    |}]
+;;
+
+let%expect_test "[@sexp_grammar.any] in [@@deriving]" =
+  show_grammar
+    (module struct
+      type t =
+        (Grammarless.t[@sexp_grammar.any "GRAMMARLESS"])
+        * (Grammarless.t[@sexp_grammar.any])
+      [@@deriving_inline sexp_grammar]
+
+      let _ = fun (_ : t) -> ()
+
+      let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+        { untyped = List (Cons (Any "GRAMMARLESS", Cons (Any "ANY", Empty))) }
+      ;;
+
+      let _ = t_sexp_grammar
+
+      [@@@end]
+    end);
+  [%expect {| (List (Cons (Any GRAMMARLESS) (Cons (Any ANY) Empty))) |}]
+;;
+
+let%expect_test "[@sexp_grammar.any] in [%sexp_grammar]" =
+  show_grammar
+    (module struct
+      type t = Grammarless.t * Grammarless.t
+
+      let t_sexp_grammar =
+        [%sexp_grammar:
+          (Grammarless.t[@sexp_grammar.any "GRAMMARLESS"])
+          * (Grammarless.t[@sexp_grammar.any])]
+      ;;
+    end);
+  [%expect {| (List (Cons (Any GRAMMARLESS) (Cons (Any ANY) Empty))) |}]
+;;

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_attributes.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_base_map.ml

@@ -0,0 +1,35 @@
+open! Base
+
+module type S = sig
+  type t [@@deriving sexp_grammar]
+end
+
+module Key = struct
+  type t = int [@@deriving sexp_grammar]
+end
+
+module Pair = struct
+  type ('a, 'b) t = 'a * 'b [@@deriving sexp_grammar]
+
+  module M (A : T) = struct
+    type 'b t = A.t * 'b
+  end
+
+  let m__t_sexp_grammar (type a) (module Key : S with type t = a) v_sexp_grammar =
+    t_sexp_grammar Key.t_sexp_grammar v_sexp_grammar
+  ;;
+end
+
+type t = string Pair.M(Key).t [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : t) -> ()
+
+let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy (lazy (Pair.m__t_sexp_grammar (module Key) string_sexp_grammar).untyped)
+  }
+;;
+
+let _ = t_sexp_grammar
+
+[@@@end]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_base_map.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_coverage_for_deriving.ml

@@ -0,0 +1,616 @@
+open Ppx_sexp_conv_lib.Conv
+
+[@@@warning "-37"] (* allow unused constructors *)
+
+type abstract_a [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : abstract_a) -> ()
+
+let (abstract_a_sexp_grammar : abstract_a Sexplib0.Sexp_grammar.t) =
+  { untyped = Any "Test_coverage_for_deriving.abstract_a" }
+;;
+
+let _ = abstract_a_sexp_grammar
+
+[@@@end]
+
+type abstract_b [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : abstract_b) -> ()
+
+let (abstract_b_sexp_grammar : abstract_b Sexplib0.Sexp_grammar.t) =
+  { untyped = Any "Test_coverage_for_deriving.abstract_b" }
+;;
+
+let _ = abstract_b_sexp_grammar
+
+[@@@end]
+
+type integer = int [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : integer) -> ()
+let (integer_sexp_grammar : integer Sexplib0.Sexp_grammar.t) = int_sexp_grammar
+let _ = integer_sexp_grammar
+
+[@@@end]
+
+type tuple = int * string [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : tuple) -> ()
+
+let (tuple_sexp_grammar : tuple Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy
+        (lazy
+          (List
+             (Cons (int_sexp_grammar.untyped, Cons (string_sexp_grammar.untyped, Empty)))))
+  }
+;;
+
+let _ = tuple_sexp_grammar
+
+[@@@end]
+
+type pos =
+  { x : float
+  ; y : float
+  }
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : pos) -> ()
+
+let (pos_sexp_grammar : pos Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy
+        (lazy
+          (List
+             (Fields
+                { allow_extra_fields = false
+                ; fields =
+                    [ No_tag
+                        { name = "x"
+                        ; required = true
+                        ; args = Cons (float_sexp_grammar.untyped, Empty)
+                        }
+                    ; No_tag
+                        { name = "y"
+                        ; required = true
+                        ; args = Cons (float_sexp_grammar.untyped, Empty)
+                        }
+                    ]
+                })))
+  }
+;;
+
+let _ = pos_sexp_grammar
+
+[@@@end]
+
+type 'a unary = 'a list [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : 'a unary) -> ()
+
+let unary_sexp_grammar :
+      'a. 'a Sexplib0.Sexp_grammar.t -> 'a unary Sexplib0.Sexp_grammar.t
+  =
+  fun _'a_sexp_grammar -> list_sexp_grammar _'a_sexp_grammar
+;;
+
+let _ = unary_sexp_grammar
+
+[@@@end]
+
+type enum =
+  | One
+  | Two
+  | Three
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : enum) -> ()
+
+let (enum_sexp_grammar : enum Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Variant
+        { case_sensitivity = Case_sensitive_except_first_character
+        ; clauses =
+            [ No_tag { name = "One"; clause_kind = Atom_clause }
+            ; No_tag { name = "Two"; clause_kind = Atom_clause }
+            ; No_tag { name = "Three"; clause_kind = Atom_clause }
+            ]
+        }
+  }
+;;
+
+let _ = enum_sexp_grammar
+
+[@@@end]
+
+type ('a, 'b) which =
+  | This of 'a
+  | That of 'b
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : ('a, 'b) which) -> ()
+
+let which_sexp_grammar :
+      'a 'b.
+      'a Sexplib0.Sexp_grammar.t
+      -> 'b Sexplib0.Sexp_grammar.t
+      -> ('a, 'b) which Sexplib0.Sexp_grammar.t
+  =
+  fun _'a_sexp_grammar _'b_sexp_grammar ->
+  { untyped =
+      Variant
+        { case_sensitivity = Case_sensitive_except_first_character
+        ; clauses =
+            [ No_tag
+                { name = "This"
+                ; clause_kind =
+                    List_clause { args = Cons (_'a_sexp_grammar.untyped, Empty) }
+                }
+            ; No_tag
+                { name = "That"
+                ; clause_kind =
+                    List_clause { args = Cons (_'b_sexp_grammar.untyped, Empty) }
+                }
+            ]
+        }
+  }
+;;
+
+let _ = which_sexp_grammar
+
+[@@@end]
+
+type 'a optional =
+  | No
+  | Yes of 'a
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : 'a optional) -> ()
+
+let optional_sexp_grammar :
+      'a. 'a Sexplib0.Sexp_grammar.t -> 'a optional Sexplib0.Sexp_grammar.t
+  =
+  fun _'a_sexp_grammar ->
+  { untyped =
+      Variant
+        { case_sensitivity = Case_sensitive_except_first_character
+        ; clauses =
+            [ No_tag { name = "No"; clause_kind = Atom_clause }
+            ; No_tag
+                { name = "Yes"
+                ; clause_kind =
+                    List_clause { args = Cons (_'a_sexp_grammar.untyped, Empty) }
+                }
+            ]
+        }
+  }
+;;
+
+let _ = optional_sexp_grammar
+
+[@@@end]
+
+type empty = | [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : empty) -> ()
+let (empty_sexp_grammar : empty Sexplib0.Sexp_grammar.t) = { untyped = Union [] }
+let _ = empty_sexp_grammar
+
+[@@@end]
+
+type _ phantom = int [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : _ phantom) -> ()
+
+let phantom_sexp_grammar :
+      'a__086_.
+      'a__086_ Sexplib0.Sexp_grammar.t -> 'a__086_ phantom Sexplib0.Sexp_grammar.t
+  =
+  fun _'a__086__sexp_grammar -> int_sexp_grammar
+;;
+
+let _ = phantom_sexp_grammar
+
+[@@@end]
+
+type color =
+  [ `Red
+  | `Blue
+  ]
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : color) -> ()
+
+let (color_sexp_grammar : color Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Variant
+        { case_sensitivity = Case_sensitive
+        ; clauses =
+            [ No_tag { name = "Red"; clause_kind = Atom_clause }
+            ; No_tag { name = "Blue"; clause_kind = Atom_clause }
+            ]
+        }
+  }
+;;
+
+let _ = color_sexp_grammar
+
+[@@@end]
+
+type adjective =
+  [ color
+  | `Fast
+  | `Slow
+  | `Count of int
+  ]
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : adjective) -> ()
+
+let (adjective_sexp_grammar : adjective Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy
+        (lazy
+          (Union
+             [ color_sexp_grammar.untyped
+             ; Variant
+                 { case_sensitivity = Case_sensitive
+                 ; clauses =
+                     [ No_tag { name = "Fast"; clause_kind = Atom_clause }
+                     ; No_tag { name = "Slow"; clause_kind = Atom_clause }
+                     ; No_tag
+                         { name = "Count"
+                         ; clause_kind =
+                             List_clause { args = Cons (int_sexp_grammar.untyped, Empty) }
+                         }
+                     ]
+                 }
+             ]))
+  }
+;;
+
+let _ = adjective_sexp_grammar
+
+[@@@end]
+
+type 'a tree =
+  { data : 'a
+  ; children : 'a tree list
+  }
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : 'a tree) -> ()
+
+include struct
+  open struct
+    let (grammars__118_ : Sexplib0.Sexp_grammar.defn Stdlib.List.t Stdlib.Lazy.t) =
+      lazy
+        (let tree_sexp_grammar
+               : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a tree Sexplib0.Sexp_grammar.t
+           =
+           fun _'a_sexp_grammar ->
+           { untyped = Recursive ("tree", [ _'a_sexp_grammar.untyped ]) }
+         in
+         [ { tycon = "tree"
+           ; tyvars = [ "a" ]
+           ; grammar =
+               List
+                 (Fields
+                    { allow_extra_fields = false
+                    ; fields =
+                        [ No_tag
+                            { name = "data"
+                            ; required = true
+                            ; args = Cons (Tyvar "a", Empty)
+                            }
+                        ; No_tag
+                            { name = "children"
+                            ; required = true
+                            ; args =
+                                Cons
+                                  ( (list_sexp_grammar
+                                       (tree_sexp_grammar { untyped = Tyvar "a" }))
+                                      .untyped
+                                  , Empty )
+                            }
+                        ]
+                    })
+           }
+         ])
+    ;;
+
+    let _ = grammars__118_
+  end
+
+  let tree_sexp_grammar :
+        'a. 'a Sexplib0.Sexp_grammar.t -> 'a tree Sexplib0.Sexp_grammar.t
+    =
+    fun _'a_sexp_grammar ->
+    { untyped =
+        Tycon ("tree", [ _'a_sexp_grammar.untyped ], Stdlib.Lazy.force grammars__118_)
+    }
+  ;;
+
+  let _ = tree_sexp_grammar
+end
+
+[@@@end]
+
+type alpha = int
+
+and beta =
+  { alpha : alpha
+  ; betas : beta list
+  }
+
+and gamma = beta list [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : alpha) -> ()
+let _ = fun (_ : beta) -> ()
+let _ = fun (_ : gamma) -> ()
+
+include struct
+  open struct
+    let (grammars__131_ : Sexplib0.Sexp_grammar.defn Stdlib.List.t Stdlib.Lazy.t) =
+      lazy
+        (let (alpha_sexp_grammar : alpha Sexplib0.Sexp_grammar.t) =
+           { untyped = Recursive ("alpha", []) }
+         and (beta_sexp_grammar : beta Sexplib0.Sexp_grammar.t) =
+           { untyped = Recursive ("beta", []) }
+         in
+         [ { tycon = "alpha"; tyvars = []; grammar = int_sexp_grammar.untyped }
+         ; { tycon = "beta"
+           ; tyvars = []
+           ; grammar =
+               List
+                 (Fields
+                    { allow_extra_fields = false
+                    ; fields =
+                        [ No_tag
+                            { name = "alpha"
+                            ; required = true
+                            ; args = Cons (alpha_sexp_grammar.untyped, Empty)
+                            }
+                        ; No_tag
+                            { name = "betas"
+                            ; required = true
+                            ; args =
+                                Cons ((list_sexp_grammar beta_sexp_grammar).untyped, Empty)
+                            }
+                        ]
+                    })
+           }
+         ])
+    ;;
+
+    let _ = grammars__131_
+  end
+
+  let (alpha_sexp_grammar : alpha Sexplib0.Sexp_grammar.t) =
+    { untyped = Lazy (lazy (Tycon ("alpha", [], Stdlib.Lazy.force grammars__131_))) }
+
+  and (beta_sexp_grammar : beta Sexplib0.Sexp_grammar.t) =
+    { untyped = Lazy (lazy (Tycon ("beta", [], Stdlib.Lazy.force grammars__131_))) }
+  ;;
+
+  let _ = alpha_sexp_grammar
+  and _ = beta_sexp_grammar
+end
+
+let (gamma_sexp_grammar : gamma Sexplib0.Sexp_grammar.t) =
+  { untyped = Lazy (lazy (list_sexp_grammar beta_sexp_grammar).untyped) }
+;;
+
+let _ = gamma_sexp_grammar
+
+[@@@end]
+
+type record_attributes =
+  { a : int [@default 0]
+  ; b : bool [@sexp.bool]
+  ; c : float option [@sexp.option]
+  ; d : string list [@sexp.list]
+  ; e : bytes array [@sexp.array]
+  ; f : Ppx_sexp_conv_lib.Sexp.t [@sexp.omit_nil]
+  }
+[@@sexp.allow_extra_fields] [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : record_attributes) -> ()
+
+let (record_attributes_sexp_grammar : record_attributes Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy
+        (lazy
+          (List
+             (Fields
+                { allow_extra_fields = true
+                ; fields =
+                    [ No_tag
+                        { name = "a"
+                        ; required = false
+                        ; args = Cons (int_sexp_grammar.untyped, Empty)
+                        }
+                    ; No_tag { name = "b"; required = false; args = Empty }
+                    ; No_tag
+                        { name = "c"
+                        ; required = false
+                        ; args = Cons (float_sexp_grammar.untyped, Empty)
+                        }
+                    ; No_tag
+                        { name = "d"
+                        ; required = false
+                        ; args = Cons (List (Many string_sexp_grammar.untyped), Empty)
+                        }
+                    ; No_tag
+                        { name = "e"
+                        ; required = false
+                        ; args = Cons (List (Many bytes_sexp_grammar.untyped), Empty)
+                        }
+                    ; No_tag
+                        { name = "f"
+                        ; required = false
+                        ; args =
+                            Cons (Ppx_sexp_conv_lib.Sexp.t_sexp_grammar.untyped, Empty)
+                        }
+                    ]
+                })))
+  }
+;;
+
+let _ = record_attributes_sexp_grammar
+
+[@@@end]
+
+type variant_attributes =
+  | A
+  | B of int list [@sexp.list]
+  | C of
+      { a : int [@default 0]
+      ; b : bool [@sexp.bool]
+      ; c : float option [@sexp.option]
+      ; d : string list [@sexp.list]
+      ; e : bytes array [@sexp.array]
+      ; f : Ppx_sexp_conv_lib.Sexp.t [@sexp.omit_nil]
+      } [@sexp.allow_extra_fields]
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : variant_attributes) -> ()
+
+let (variant_attributes_sexp_grammar : variant_attributes Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy
+        (lazy
+          (Variant
+             { case_sensitivity = Case_sensitive_except_first_character
+             ; clauses =
+                 [ No_tag { name = "A"; clause_kind = Atom_clause }
+                 ; No_tag
+                     { name = "B"
+                     ; clause_kind = List_clause { args = Many int_sexp_grammar.untyped }
+                     }
+                 ; No_tag
+                     { name = "C"
+                     ; clause_kind =
+                         List_clause
+                           { args =
+                               Fields
+                                 { allow_extra_fields = true
+                                 ; fields =
+                                     [ No_tag
+                                         { name = "a"
+                                         ; required = false
+                                         ; args = Cons (int_sexp_grammar.untyped, Empty)
+                                         }
+                                     ; No_tag
+                                         { name = "b"; required = false; args = Empty }
+                                     ; No_tag
+                                         { name = "c"
+                                         ; required = false
+                                         ; args = Cons (float_sexp_grammar.untyped, Empty)
+                                         }
+                                     ; No_tag
+                                         { name = "d"
+                                         ; required = false
+                                         ; args =
+                                             Cons
+                                               ( List (Many string_sexp_grammar.untyped)
+                                               , Empty )
+                                         }
+                                     ; No_tag
+                                         { name = "e"
+                                         ; required = false
+                                         ; args =
+                                             Cons
+                                               ( List (Many bytes_sexp_grammar.untyped)
+                                               , Empty )
+                                         }
+                                     ; No_tag
+                                         { name = "f"
+                                         ; required = false
+                                         ; args =
+                                             Cons
+                                               ( Ppx_sexp_conv_lib.Sexp.t_sexp_grammar
+                                                   .untyped
+                                               , Empty )
+                                         }
+                                     ]
+                                 }
+                           }
+                     }
+                 ]
+             }))
+  }
+;;
+
+let _ = variant_attributes_sexp_grammar
+
+[@@@end]
+
+type polymorphic_variant_attributes =
+  [ `A
+  | `B of int list [@sexp.list]
+  ]
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : polymorphic_variant_attributes) -> ()
+
+let (polymorphic_variant_attributes_sexp_grammar :
+      polymorphic_variant_attributes Sexplib0.Sexp_grammar.t)
+  =
+  { untyped =
+      Lazy
+        (lazy
+          (Variant
+             { case_sensitivity = Case_sensitive
+             ; clauses =
+                 [ No_tag { name = "A"; clause_kind = Atom_clause }
+                 ; No_tag
+                     { name = "B"
+                     ; clause_kind = List_clause { args = Many int_sexp_grammar.untyped }
+                     }
+                 ]
+             }))
+  }
+;;
+
+let _ = polymorphic_variant_attributes_sexp_grammar
+
+[@@@end]
+
+type opaque =
+  { x : (string[@sexp.opaque])
+  ; y : int -> int
+  }
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : opaque) -> ()
+
+let (opaque_sexp_grammar : opaque Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy
+        (lazy
+          (List
+             (Fields
+                { allow_extra_fields = false
+                ; fields =
+                    [ No_tag
+                        { name = "x"
+                        ; required = true
+                        ; args =
+                            Cons (Sexplib0.Sexp_conv.opaque_sexp_grammar.untyped, Empty)
+                        }
+                    ; No_tag
+                        { name = "y"
+                        ; required = true
+                        ; args = Cons (Sexplib0.Sexp_conv.fun_sexp_grammar.untyped, Empty)
+                        }
+                    ]
+                })))
+  }
+;;
+
+let _ = opaque_sexp_grammar
+
+[@@@end]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_coverage_for_deriving.mli

@@ -0,0 +1,283 @@
+(** This file covers a lot of cases for [@@deriving], for both interface and
+    implementation. They are also exported for validation. *)
+
+type abstract_a [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val abstract_a_sexp_grammar : abstract_a Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type abstract_b [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val abstract_b_sexp_grammar : abstract_b Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type integer = int [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val integer_sexp_grammar : integer Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type tuple = int * string [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val tuple_sexp_grammar : tuple Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type pos =
+  { x : float
+  ; y : float
+  }
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val pos_sexp_grammar : pos Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type 'a unary = 'a list [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val unary_sexp_grammar : 'a Sexplib0.Sexp_grammar.t -> 'a unary Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type enum =
+  | One
+  | Two
+  | Three
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val enum_sexp_grammar : enum Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type ('a, 'b) which =
+  | This of 'a
+  | That of 'b
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val which_sexp_grammar
+    :  'a Sexplib0.Sexp_grammar.t
+    -> 'b Sexplib0.Sexp_grammar.t
+    -> ('a, 'b) which Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type 'a optional =
+  | No
+  | Yes of 'a
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val optional_sexp_grammar
+    :  'a Sexplib0.Sexp_grammar.t
+    -> 'a optional Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type empty = | [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val empty_sexp_grammar : empty Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type _ phantom = int [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val phantom_sexp_grammar
+    :  'a__003_ Sexplib0.Sexp_grammar.t
+    -> 'a__003_ phantom Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type color =
+  [ `Red
+  | `Blue
+  ]
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val color_sexp_grammar : color Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type adjective =
+  [ color
+  | `Fast
+  | `Slow
+  | `Count of int
+  ]
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val adjective_sexp_grammar : adjective Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type 'a tree =
+  { data : 'a
+  ; children : 'a tree list
+  }
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val tree_sexp_grammar : 'a Sexplib0.Sexp_grammar.t -> 'a tree Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type alpha = int
+
+and beta =
+  { alpha : alpha
+  ; betas : beta list
+  }
+
+and gamma = beta list [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val alpha_sexp_grammar : alpha Sexplib0.Sexp_grammar.t
+  val beta_sexp_grammar : beta Sexplib0.Sexp_grammar.t
+  val gamma_sexp_grammar : gamma Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type record_attributes =
+  { a : int
+  ; b : bool
+  ; c : float option
+  ; d : string list
+  ; e : bytes array
+  ; f : Ppx_sexp_conv_lib.Sexp.t
+  }
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val record_attributes_sexp_grammar : record_attributes Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type variant_attributes =
+  | A
+  | B of int list
+  | C of
+      { a : int
+      ; b : bool
+      ; c : float option
+      ; d : string list
+      ; e : bytes array
+      ; f : Ppx_sexp_conv_lib.Sexp.t
+      }
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val variant_attributes_sexp_grammar : variant_attributes Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type polymorphic_variant_attributes =
+  [ `A
+  | `B of int list
+  ]
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val polymorphic_variant_attributes_sexp_grammar
+    : polymorphic_variant_attributes Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]
+
+type opaque =
+  { x : string
+  ; y : int -> int
+  }
+[@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+include sig
+  [@@@ocaml.warning "-32"]
+
+  val opaque_sexp_grammar : opaque Sexplib0.Sexp_grammar.t
+end
+[@@ocaml.doc "@inline"]
+
+[@@@end]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_extension.ml

@@ -0,0 +1,19 @@
+open! Base
+
+(* Not sure how much people will want to use this, considering that the input is more
+   complicated and specific than the output, but they have it. *)
+module type S = sig
+  val t_sexp_grammar : [%sexp_grammar: int Map.M(String).t]
+end
+
+module _ (M : S) : sig
+  val t_sexp_grammar : int Map.M(String).t Sexplib0.Sexp_grammar.t [@@warning "-32"]
+end =
+  M
+
+(* The grammar is illegible, so just make sure it builds. *)
+
+let (_ : _ Sexplib0.Sexp_grammar.t) = [%sexp_grammar: int Map.M(String).t]
+
+(* This used to give a compilation error. *)
+let (_ : _ Sexplib0.Sexp_grammar.t) = [%sexp_grammar: _ list]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_extension.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_functors.ml

@@ -0,0 +1,158 @@
+open! Base
+
+module Maybe = struct
+  type 'a t = 'a option [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : 'a t) -> ()
+
+  let t_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t =
+    fun _'a_sexp_grammar -> option_sexp_grammar _'a_sexp_grammar
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module Make (T : sig
+  type 'a t [@@deriving sexp_grammar]
+end) =
+struct
+  [@@@warning "-37"]
+
+  type 'a t = T of 'a T.t u
+  and 'a u = U of 'a T.t t Maybe.t [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : 'a t) -> ()
+  let _ = fun (_ : 'a u) -> ()
+
+  include struct
+    open struct
+      let (grammars__001_ : Sexplib0.Sexp_grammar.defn Stdlib.List.t Stdlib.Lazy.t) =
+        lazy
+          (let t_sexp_grammar
+                 : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t
+             =
+             fun _'a_sexp_grammar ->
+             { untyped = Recursive ("t", [ _'a_sexp_grammar.untyped ]) }
+           and u_sexp_grammar
+                 : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a u Sexplib0.Sexp_grammar.t
+             =
+             fun _'a_sexp_grammar ->
+             { untyped = Recursive ("u", [ _'a_sexp_grammar.untyped ]) }
+           in
+           [ { tycon = "t"
+             ; tyvars = [ "a" ]
+             ; grammar =
+                 Variant
+                   { case_sensitivity = Case_sensitive_except_first_character
+                   ; clauses =
+                       [ No_tag
+                           { name = "T"
+                           ; clause_kind =
+                               List_clause
+                                 { args =
+                                     Cons
+                                       ( (u_sexp_grammar
+                                            (T.t_sexp_grammar { untyped = Tyvar "a" }))
+                                           .untyped
+                                       , Empty )
+                                 }
+                           }
+                       ]
+                   }
+             }
+           ; { tycon = "u"
+             ; tyvars = [ "a" ]
+             ; grammar =
+                 Variant
+                   { case_sensitivity = Case_sensitive_except_first_character
+                   ; clauses =
+                       [ No_tag
+                           { name = "U"
+                           ; clause_kind =
+                               List_clause
+                                 { args =
+                                     Cons
+                                       ( (Maybe.t_sexp_grammar
+                                            (t_sexp_grammar
+                                               (T.t_sexp_grammar { untyped = Tyvar "a" })))
+                                           .untyped
+                                       , Empty )
+                                 }
+                           }
+                       ]
+                   }
+             }
+           ])
+      ;;
+
+      let _ = grammars__001_
+    end
+
+    let t_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t =
+      fun _'a_sexp_grammar ->
+      { untyped =
+          Tycon ("t", [ _'a_sexp_grammar.untyped ], Stdlib.Lazy.force grammars__001_)
+      }
+
+    and u_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a u Sexplib0.Sexp_grammar.t =
+      fun _'a_sexp_grammar ->
+      { untyped =
+          Tycon ("u", [ _'a_sexp_grammar.untyped ], Stdlib.Lazy.force grammars__001_)
+      }
+    ;;
+
+    let _ = t_sexp_grammar
+    and _ = u_sexp_grammar
+  end
+
+  [@@@end]
+
+  type 'a v = V of 'a t [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : 'a v) -> ()
+
+  let v_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a v Sexplib0.Sexp_grammar.t =
+    fun _'a_sexp_grammar ->
+    { untyped =
+        Variant
+          { case_sensitivity = Case_sensitive_except_first_character
+          ; clauses =
+              [ No_tag
+                  { name = "V"
+                  ; clause_kind =
+                      List_clause
+                        { args = Cons ((t_sexp_grammar _'a_sexp_grammar).untyped, Empty) }
+                  }
+              ]
+          }
+    }
+  ;;
+
+  let _ = v_sexp_grammar
+
+  [@@@end]
+end
+
+module T1 = Make (Maybe)
+module T2 = Make (T1)
+
+type t = int T2.t * int T1.t [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : t) -> ()
+
+let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy
+        (lazy
+          (List
+             (Cons
+                ( (T2.t_sexp_grammar int_sexp_grammar).untyped
+                , Cons ((T1.t_sexp_grammar int_sexp_grammar).untyped, Empty) ))))
+  }
+;;
+
+let _ = t_sexp_grammar
+
+[@@@end]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_functors.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_gadt.ml

@@ -0,0 +1,75 @@
+open! Base
+
+type t = T : ('a[@sexp.opaque]) -> t [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : t) -> ()
+
+let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy
+        (lazy
+          (Variant
+             { case_sensitivity = Case_sensitive_except_first_character
+             ; clauses =
+                 [ No_tag
+                     { name = "T"
+                     ; clause_kind =
+                         List_clause
+                           { args =
+                               Cons (Sexplib0.Sexp_conv.opaque_sexp_grammar.untyped, Empty)
+                           }
+                     }
+                 ]
+             }))
+  }
+;;
+
+let _ = t_sexp_grammar
+
+[@@@end]
+
+type nullary = Nullary : nullary [@@deriving sexp] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : nullary) -> ()
+
+let (nullary_sexp_grammar : nullary Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Variant
+        { case_sensitivity = Case_sensitive_except_first_character
+        ; clauses = [ No_tag { name = "Nullary"; clause_kind = Atom_clause } ]
+        }
+  }
+;;
+
+let _ = nullary_sexp_grammar
+
+[@@@end]
+
+(* We can't derive [of_sexp], but we can derive a sensible grammar for this type. *)
+type _ grammar_only = Grammar_only : int -> string grammar_only
+[@@warning "-37"] [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : _ grammar_only) -> ()
+
+let grammar_only_sexp_grammar :
+      'a__016_.
+      'a__016_ Sexplib0.Sexp_grammar.t -> 'a__016_ grammar_only Sexplib0.Sexp_grammar.t
+  =
+  fun _'a__016__sexp_grammar ->
+  { untyped =
+      Variant
+        { case_sensitivity = Case_sensitive_except_first_character
+        ; clauses =
+            [ No_tag
+                { name = "Grammar_only"
+                ; clause_kind =
+                    List_clause { args = Cons (int_sexp_grammar.untyped, Empty) }
+                }
+            ]
+        }
+  }
+;;
+
+let _ = grammar_only_sexp_grammar
+
+[@@@end]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_gadt.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_nonrec.ml

@@ -0,0 +1,19 @@
+open! Base
+
+open struct
+  type t = int [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) = int_sexp_grammar
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+type nonrec t = t [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : t) -> ()
+let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) = t_sexp_grammar
+let _ = t_sexp_grammar
+
+[@@@end]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_nonrec.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_opaque.ml

@@ -0,0 +1,15 @@
+open! Base
+
+type t = (int[@sexp.opaque]) list [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : t) -> ()
+
+let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy (lazy (list_sexp_grammar Sexplib0.Sexp_conv.opaque_sexp_grammar).untyped)
+  }
+;;
+
+let _ = t_sexp_grammar
+
+[@@@end]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_opaque.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_polymorphic_variants.ml

@@ -0,0 +1,171 @@
+open Base
+
+[@@@warning "-37"]
+
+module _ = struct
+  type 'a t =
+    [ `A
+    | `B
+    ]
+  [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : 'a t) -> ()
+
+  let t_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t =
+    fun _'a_sexp_grammar ->
+    { untyped =
+        Variant
+          { case_sensitivity = Case_sensitive
+          ; clauses =
+              [ No_tag { name = "A"; clause_kind = Atom_clause }
+              ; No_tag { name = "B"; clause_kind = Atom_clause }
+              ]
+          }
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module _ = struct
+  module With_sexp = struct
+    type t =
+      [ `A of int * int
+      | `B of string
+      ]
+    [@@deriving sexp_of]
+  end
+
+  type t =
+    [ `A of int * int
+    | `B of string
+    ]
+  [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (Variant
+               { case_sensitivity = Case_sensitive
+               ; clauses =
+                   [ No_tag
+                       { name = "A"
+                       ; clause_kind =
+                           List_clause
+                             { args =
+                                 Cons
+                                   ( List
+                                       (Cons
+                                          ( int_sexp_grammar.untyped
+                                          , Cons (int_sexp_grammar.untyped, Empty) ))
+                                   , Empty )
+                             }
+                       }
+                   ; No_tag
+                       { name = "B"
+                       ; clause_kind =
+                           List_clause
+                             { args = Cons (string_sexp_grammar.untyped, Empty) }
+                       }
+                   ]
+               }))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+
+  open Expect_test_helpers_base
+
+  let%expect_test _ =
+    print_s (With_sexp.sexp_of_t (`A (1, 2)));
+    print_s (With_sexp.sexp_of_t (`B "foo"));
+    [%expect {|
+      (A (1 2))
+      (B foo)
+      |}]
+  ;;
+end
+
+module _ = struct
+  module With_sexp = struct
+    type t =
+      [ `Int of int
+      | `List of int list
+      | `Sexp_dot_list of int list [@sexp.list]
+      ]
+    [@@deriving sexp]
+  end
+
+  type t =
+    [ `Int of int
+    | `List of int list
+    | `Sexp_dot_list of int list [@sexp.list]
+    ]
+  [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (Variant
+               { case_sensitivity = Case_sensitive
+               ; clauses =
+                   [ No_tag
+                       { name = "Int"
+                       ; clause_kind =
+                           List_clause { args = Cons (int_sexp_grammar.untyped, Empty) }
+                       }
+                   ; No_tag
+                       { name = "List"
+                       ; clause_kind =
+                           List_clause
+                             { args =
+                                 Cons ((list_sexp_grammar int_sexp_grammar).untyped, Empty)
+                             }
+                       }
+                   ; No_tag
+                       { name = "Sexp_dot_list"
+                       ; clause_kind =
+                           List_clause { args = Many int_sexp_grammar.untyped }
+                       }
+                   ]
+               }))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+
+  let (T : (With_sexp.t, t) Type_equal.t) = T
+
+  open Expect_test_helpers_base
+
+  let%expect_test _ =
+    print_s (With_sexp.sexp_of_t (`Int 1));
+    List.iter
+      [ []; [ 1 ]; [ 1; 2 ] ]
+      ~f:(fun l ->
+        print_s (With_sexp.sexp_of_t (`List l));
+        print_s (With_sexp.sexp_of_t (`Sexp_dot_list l)));
+    [%expect
+      {|
+      (Int 1)
+      (List ())
+      (Sexp_dot_list)
+      (List (1))
+      (Sexp_dot_list 1)
+      (List (1 2))
+      (Sexp_dot_list 1 2)
+      |}]
+  ;;
+end

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_polymorphic_variants.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_polymorphic_variants.mlt

@@ -0,0 +1,115 @@
+(* This toplevel test exercises some polymorphic variants that sexp_grammar rejects. We
+   show that in each case, the compiler or sexp would have given an error anyway. *)
+
+open Base
+
+type t = [ `A of int & string ] [@@deriving sexp]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: unsupported: polymorphic variant intersection type
+|}]
+
+type t = [ `A of int & string ] [@@deriving sexp_grammar]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: sexp_grammar: intersection types are unsupported
+|}]
+
+type t = [> `A ] [@@deriving sexp]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: Type unsupported for ppx [of_sexp] conversion
+|}]
+
+type t = [> `A ] [@@deriving sexp_grammar]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: sexp_grammar: open polymorphic variant types are unsupported
+|}]
+
+type t = [< `A ] [@@deriving sexp]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: A type variable is unbound in this type declaration.
+       In type [< `A ] as 'a the variable 'a is unbound
+|}]
+
+type t = [< `A ] [@@deriving sexp_grammar]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: A type variable is unbound in this type declaration.
+       In type [< `A ] as 'a the variable 'a is unbound
+|}]
+
+type 'a t = [< `A ] as 'a [@@deriving sexp]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: Type unsupported for ppx [of_sexp] conversion
+|}]
+
+type 'a t = [< `A ] as 'a [@@deriving sexp_grammar]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: sexp_grammar: type aliases are unsupported
+|}]
+
+type a = A : [> ] -> a [@@deriving sexp]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: Type unsupported for ppx [of_sexp] conversion
+|}]
+
+type a = A : [> ] -> a [@@deriving sexp_of]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: Type unsupported for ppx [sexp_of] conversion
+|}]
+
+type a = [ `A ] [@@deriving sexp];;
+
+#verbose true
+
+let f = [%sexp_of: [< a ]]
+
+[%%expect
+  {|
+val f : [< a ] -> Sexp.t = <fun>
+|}]
+
+let f = [%of_sexp: [> a ]]
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: Type unsupported for ppx [of_sexp] conversion
+|}]
+
+let f = [%of_sexp: [ | a ]]
+
+[%%expect
+  {|
+val f : Sexp.t -> a = <fun>
+|}]
+;;
+
+#verbose false

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_polymorphism.ml

@@ -0,0 +1,34 @@
+open! Base
+
+type ('a, _, 'b) t = 'a * 'b
+and u = (string, int, float) t [@@deriving_inline sexp_grammar]
+
+let _ = fun (_ : ('a, _, 'b) t) -> ()
+let _ = fun (_ : u) -> ()
+
+let t_sexp_grammar :
+      'a 'b__001_ 'b.
+      'a Sexplib0.Sexp_grammar.t
+      -> 'b__001_ Sexplib0.Sexp_grammar.t
+      -> 'b Sexplib0.Sexp_grammar.t
+      -> ('a, 'b__001_, 'b) t Sexplib0.Sexp_grammar.t
+  =
+  fun _'a_sexp_grammar _'b__001__sexp_grammar _'b_sexp_grammar ->
+  { untyped =
+      List (Cons (_'a_sexp_grammar.untyped, Cons (_'b_sexp_grammar.untyped, Empty)))
+  }
+;;
+
+let _ = t_sexp_grammar
+
+let (u_sexp_grammar : u Sexplib0.Sexp_grammar.t) =
+  { untyped =
+      Lazy
+        (lazy
+          (t_sexp_grammar string_sexp_grammar int_sexp_grammar float_sexp_grammar).untyped)
+  }
+;;
+
+let _ = u_sexp_grammar
+
+[@@@end]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_polymorphism.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_recursive_groups.ml

@@ -0,0 +1,112 @@
+open Base
+
+[@@@warning "-37"]
+
+module _ = struct
+  type t = T of int [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (Variant
+               { case_sensitivity = Case_sensitive_except_first_character
+               ; clauses =
+                   [ No_tag
+                       { name = "T"
+                       ; clause_kind =
+                           List_clause { args = Cons (int_sexp_grammar.untyped, Empty) }
+                       }
+                   ]
+               }))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module _ = struct
+  type t =
+    | T_int of int
+    | T_u of u
+
+  and u =
+    | U_int of int
+    | U_t of t
+  [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+  let _ = fun (_ : u) -> ()
+
+  include struct
+    open struct
+      let (grammars__001_ : Sexplib0.Sexp_grammar.defn Stdlib.List.t Stdlib.Lazy.t) =
+        lazy
+          (let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+             { untyped = Recursive ("t", []) }
+           and (u_sexp_grammar : u Sexplib0.Sexp_grammar.t) =
+             { untyped = Recursive ("u", []) }
+           in
+           [ { tycon = "t"
+             ; tyvars = []
+             ; grammar =
+                 Variant
+                   { case_sensitivity = Case_sensitive_except_first_character
+                   ; clauses =
+                       [ No_tag
+                           { name = "T_int"
+                           ; clause_kind =
+                               List_clause
+                                 { args = Cons (int_sexp_grammar.untyped, Empty) }
+                           }
+                       ; No_tag
+                           { name = "T_u"
+                           ; clause_kind =
+                               List_clause { args = Cons (u_sexp_grammar.untyped, Empty) }
+                           }
+                       ]
+                   }
+             }
+           ; { tycon = "u"
+             ; tyvars = []
+             ; grammar =
+                 Variant
+                   { case_sensitivity = Case_sensitive_except_first_character
+                   ; clauses =
+                       [ No_tag
+                           { name = "U_int"
+                           ; clause_kind =
+                               List_clause
+                                 { args = Cons (int_sexp_grammar.untyped, Empty) }
+                           }
+                       ; No_tag
+                           { name = "U_t"
+                           ; clause_kind =
+                               List_clause { args = Cons (t_sexp_grammar.untyped, Empty) }
+                           }
+                       ]
+                   }
+             }
+           ])
+      ;;
+
+      let _ = grammars__001_
+    end
+
+    let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+      { untyped = Lazy (lazy (Tycon ("t", [], Stdlib.Lazy.force grammars__001_))) }
+
+    and (u_sexp_grammar : u Sexplib0.Sexp_grammar.t) =
+      { untyped = Lazy (lazy (Tycon ("u", [], Stdlib.Lazy.force grammars__001_))) }
+    ;;
+
+    let _ = t_sexp_grammar
+    and _ = u_sexp_grammar
+  end
+
+  [@@@end]
+end

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_recursive_groups.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_regular_variants.ml

@@ -0,0 +1,163 @@
+open Base
+
+[@@@warning "-37"]
+
+module _ = struct
+  type 'a t =
+    | A
+    | B
+  [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : 'a t) -> ()
+
+  let t_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t =
+    fun _'a_sexp_grammar ->
+    { untyped =
+        Variant
+          { case_sensitivity = Case_sensitive_except_first_character
+          ; clauses =
+              [ No_tag { name = "A"; clause_kind = Atom_clause }
+              ; No_tag { name = "B"; clause_kind = Atom_clause }
+              ]
+          }
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module _ = struct
+  module With_sexp = struct
+    type t =
+      | A of int * int
+      | B of string
+    [@@deriving sexp_of]
+  end
+
+  type t = With_sexp.t =
+    | A of int * int
+    | B of string
+  [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (Variant
+               { case_sensitivity = Case_sensitive_except_first_character
+               ; clauses =
+                   [ No_tag
+                       { name = "A"
+                       ; clause_kind =
+                           List_clause
+                             { args =
+                                 Cons
+                                   ( int_sexp_grammar.untyped
+                                   , Cons (int_sexp_grammar.untyped, Empty) )
+                             }
+                       }
+                   ; No_tag
+                       { name = "B"
+                       ; clause_kind =
+                           List_clause
+                             { args = Cons (string_sexp_grammar.untyped, Empty) }
+                       }
+                   ]
+               }))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+
+  open Expect_test_helpers_base
+
+  let%expect_test _ =
+    print_s (With_sexp.sexp_of_t (A (1, 2)));
+    print_s (With_sexp.sexp_of_t (B "foo"));
+    [%expect {|
+      (A 1 2)
+      (B foo)
+      |}]
+  ;;
+end
+
+module _ = struct
+  module With_sexp = struct
+    type t =
+      | Int of int
+      | List of int list
+      | Sexp_dot_list of int list [@sexp.list]
+    [@@deriving sexp]
+  end
+
+  type t = With_sexp.t =
+    | Int of int
+    | List of int list
+    | Sexp_dot_list of int list [@sexp.list]
+  [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (Variant
+               { case_sensitivity = Case_sensitive_except_first_character
+               ; clauses =
+                   [ No_tag
+                       { name = "Int"
+                       ; clause_kind =
+                           List_clause { args = Cons (int_sexp_grammar.untyped, Empty) }
+                       }
+                   ; No_tag
+                       { name = "List"
+                       ; clause_kind =
+                           List_clause
+                             { args =
+                                 Cons ((list_sexp_grammar int_sexp_grammar).untyped, Empty)
+                             }
+                       }
+                   ; No_tag
+                       { name = "Sexp_dot_list"
+                       ; clause_kind =
+                           List_clause { args = Many int_sexp_grammar.untyped }
+                       }
+                   ]
+               }))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+
+  let (T : (With_sexp.t, t) Type_equal.t) = T
+
+  open Expect_test_helpers_base
+
+  let%expect_test _ =
+    print_s (With_sexp.sexp_of_t (Int 1));
+    List.iter
+      [ []; [ 1 ]; [ 1; 2 ] ]
+      ~f:(fun l ->
+        print_s (With_sexp.sexp_of_t (List l));
+        print_s (With_sexp.sexp_of_t (Sexp_dot_list l)));
+    [%expect
+      {|
+      (Int 1)
+      (List ())
+      (Sexp_dot_list)
+      (List (1))
+      (Sexp_dot_list 1)
+      (List (1 2))
+      (Sexp_dot_list 1 2)
+      |}]
+  ;;
+end

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_regular_variants.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_tag_type_names.ml

@@ -0,0 +1,179 @@
+open! Base
+
+module _ = struct
+  (* Nonrecursive constant *)
+  type t = [ `T of int ] [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (Variant
+               { case_sensitivity = Case_sensitive
+               ; clauses =
+                   [ No_tag
+                       { name = "T"
+                       ; clause_kind =
+                           List_clause { args = Cons (int_sexp_grammar.untyped, Empty) }
+                       }
+                   ]
+               }))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module _ = struct
+  (* Recursive constant *)
+  type t = [ `T of t ] [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  include struct
+    open struct
+      let (grammars__001_ : Sexplib0.Sexp_grammar.defn Stdlib.List.t Stdlib.Lazy.t) =
+        lazy
+          (let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+             { untyped = Recursive ("t", []) }
+           in
+           [ { tycon = "t"
+             ; tyvars = []
+             ; grammar =
+                 Variant
+                   { case_sensitivity = Case_sensitive
+                   ; clauses =
+                       [ No_tag
+                           { name = "T"
+                           ; clause_kind =
+                               List_clause { args = Cons (t_sexp_grammar.untyped, Empty) }
+                           }
+                       ]
+                   }
+             }
+           ])
+      ;;
+
+      let _ = grammars__001_
+    end
+
+    let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+      { untyped = Lazy (lazy (Tycon ("t", [], Stdlib.Lazy.force grammars__001_))) }
+    ;;
+
+    let _ = t_sexp_grammar
+  end
+
+  [@@@end]
+end
+
+module _ = struct
+  (* Nonrecursive parameterized *)
+  type 'a t = [ `T of 'a ] [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : 'a t) -> ()
+
+  let t_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t =
+    fun _'a_sexp_grammar ->
+    { untyped =
+        Variant
+          { case_sensitivity = Case_sensitive
+          ; clauses =
+              [ No_tag
+                  { name = "T"
+                  ; clause_kind =
+                      List_clause { args = Cons (_'a_sexp_grammar.untyped, Empty) }
+                  }
+              ]
+          }
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module _ = struct
+  (* Recursive parameterized *)
+  type 'a t = [ `T of 'a t ] [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : 'a t) -> ()
+
+  include struct
+    open struct
+      let (grammars__002_ : Sexplib0.Sexp_grammar.defn Stdlib.List.t Stdlib.Lazy.t) =
+        lazy
+          (let t_sexp_grammar
+                 : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t
+             =
+             fun _'a_sexp_grammar ->
+             { untyped = Recursive ("t", [ _'a_sexp_grammar.untyped ]) }
+           in
+           [ { tycon = "t"
+             ; tyvars = [ "a" ]
+             ; grammar =
+                 Variant
+                   { case_sensitivity = Case_sensitive
+                   ; clauses =
+                       [ No_tag
+                           { name = "T"
+                           ; clause_kind =
+                               List_clause
+                                 { args =
+                                     Cons
+                                       ( (t_sexp_grammar { untyped = Tyvar "a" }).untyped
+                                       , Empty )
+                                 }
+                           }
+                       ]
+                   }
+             }
+           ])
+      ;;
+
+      let _ = grammars__002_
+    end
+
+    let t_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t =
+      fun _'a_sexp_grammar ->
+      { untyped =
+          Tycon ("t", [ _'a_sexp_grammar.untyped ], Stdlib.Lazy.force grammars__002_)
+      }
+    ;;
+
+    let _ = t_sexp_grammar
+  end
+
+  [@@@end]
+end
+
+module _ = struct
+  (* Aliasing of non-parameterized type *)
+  type t = int [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) = int_sexp_grammar
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module _ = struct
+  (* Aliasing of parameterized type *)
+  type 'a t = 'a list [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : 'a t) -> ()
+
+  let t_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t =
+    fun _'a_sexp_grammar -> list_sexp_grammar _'a_sexp_grammar
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_tag_type_names.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_tags.ml

@@ -0,0 +1,493 @@
+open Base
+
+module _ = struct
+  module type S = sig
+    type t [@@deriving sexp_grammar]
+  end
+
+  let show_grammar (module M : S) =
+    Expect_test_helpers_base.print_s ([%sexp_of: _ Sexp_grammar.t] [%sexp_grammar: M.t])
+  ;;
+
+  let%expect_test "basic" =
+    show_grammar
+      (module struct
+        type nonrec t = (unit[@tag "key" = Atom "value"]) [@@deriving sexp_grammar]
+      end);
+    [%expect
+      {|
+      (Tagged (
+        (key   key)
+        (value value)
+        (grammar (List Empty))))
+      |}]
+  ;;
+
+  let%expect_test "tag ordering" =
+    show_grammar
+      (module struct
+        type nonrec t =
+          (unit
+          [@tag
+            "key1" = Atom "value1";
+            "key2" = Atom "value2"])
+        [@@deriving sexp_grammar]
+      end);
+    [%expect
+      {|
+      (Tagged (
+        (key   key1)
+        (value value1)
+        (grammar (
+          Tagged (
+            (key   key2)
+            (value value2)
+            (grammar (List Empty)))))))
+      |}]
+  ;;
+
+  let%expect_test "tag idents/expressions" =
+    show_grammar
+      (module struct
+        let k = "key"
+        let v = Sexp.Atom "value"
+        let kf () = k
+        let vf () = v
+
+        type nonrec t =
+          (unit
+          [@tag
+            k = v;
+            kf () = vf ()])
+        [@@deriving sexp_grammar]
+      end);
+    [%expect
+      {|
+      (Tagged (
+        (key   key)
+        (value value)
+        (grammar (
+          Tagged (
+            (key   key)
+            (value value)
+            (grammar (List Empty)))))))
+      |}]
+  ;;
+
+  let%expect_test "tag nesting" =
+    show_grammar
+      (module struct
+        type nonrec t' = (unit[@sexp_grammar.tag "inner" = Atom "inner value"])
+        [@@deriving sexp_grammar]
+
+        type nonrec t = (t'[@sexp_grammar.tag "outer" = Atom "outer value"])
+        [@@deriving sexp_grammar]
+      end);
+    [%expect
+      {|
+      (Tagged (
+        (key   outer)
+        (value "outer value")
+        (grammar (
+          Tagged (
+            (key   inner)
+            (value "inner value")
+            (grammar (List Empty)))))))
+      |}]
+  ;;
+
+  let%expect_test "@tags attribute" =
+    (* literal constant *)
+    show_grammar
+      (module struct
+        type t = (unit[@tags [ "y", Atom "Y"; "z", Atom "Z" ]]) [@@deriving sexp_grammar]
+      end);
+    [%expect
+      {|
+      (Tagged (
+        (key   y)
+        (value Y)
+        (grammar (
+          Tagged (
+            (key   z)
+            (value Z)
+            (grammar (List Empty)))))))
+      |}];
+    (* non-constant expression *)
+    show_grammar
+      (module struct
+        type t =
+          (unit
+          [@tags List.concat [ [ "x", Sexp.Atom "X" ]; [ "y", Atom "Y"; "z", Atom "Z" ] ]])
+        [@@deriving sexp_grammar]
+      end);
+    [%expect
+      {|
+      (Tagged (
+        (key   x)
+        (value X)
+        (grammar (
+          Tagged (
+            (key   y)
+            (value Y)
+            (grammar (
+              Tagged (
+                (key   z)
+                (value Z)
+                (grammar (List Empty))))))))))
+      |}];
+    (* cons onto non-constant expression *)
+    show_grammar
+      (module struct
+        type t =
+          (unit
+          [@tags
+            ("w", Sexp.Atom "W")
+            :: List.concat [ [ "x", Sexp.Atom "X" ]; [ "y", Atom "Y"; "z", Atom "Z" ] ]])
+        [@@deriving sexp_grammar]
+      end);
+    [%expect
+      {|
+      (Tagged (
+        (key   w)
+        (value W)
+        (grammar (
+          Tagged (
+            (key   x)
+            (value X)
+            (grammar (
+              Tagged (
+                (key   y)
+                (value Y)
+                (grammar (
+                  Tagged (
+                    (key   z)
+                    (value Z)
+                    (grammar (List Empty)))))))))))))
+      |}];
+    (* empty *)
+    show_grammar
+      (module struct
+        type t = (unit[@tags List.concat []]) [@@deriving sexp_grammar]
+      end);
+    [%expect {| (List Empty) |}];
+    (* with [@tag] *)
+    show_grammar
+      (module struct
+        type t = (unit[@tag "a" = Atom "A"] [@tags [ "b", Atom "B" ]])
+        [@@deriving sexp_grammar]
+      end);
+    [%expect
+      {|
+      (Tagged (
+        (key   a)
+        (value A)
+        (grammar (
+          Tagged (
+            (key   b)
+            (value B)
+            (grammar (List Empty)))))))
+      |}]
+  ;;
+
+  let%expect_test "doc comments - variant clauses" =
+    show_grammar
+      (module struct
+        [@@@ocaml.warning "-37"]
+
+        (** IGNORED *)
+        type t =
+          | Clause0 of (unit[@tag "k0" = Atom "v0"]) (** first clause *)
+          | Clause1 [@tag "k1" = Atom "v1"] (** second clause *)
+        [@@deriving sexp_grammar ~tags_of_doc_comments]
+        (** IGNORED *)
+      end);
+    [%expect
+      {|
+      (Variant (
+        (case_sensitivity Case_sensitive_except_first_character)
+        (clauses (
+          (Tag (
+            (key   sexp_grammar.doc_comment)
+            (value " first clause ")
+            (grammar (
+              No_tag (
+                (name Clause0)
+                (clause_kind (
+                  List_clause (
+                    args (
+                      Cons
+                      (Tagged (
+                        (key   k0)
+                        (value v0)
+                        (grammar (List Empty))))
+                      Empty)))))))))
+          (Tag (
+            (key   sexp_grammar.doc_comment)
+            (value " second clause ")
+            (grammar (
+              Tag (
+                (key   k1)
+                (value v1)
+                (grammar (
+                  No_tag (
+                    (name        Clause1)
+                    (clause_kind Atom_clause)))))))))))))
+      |}]
+  ;;
+
+  let%expect_test "doc comments - poly variant clauses" =
+    show_grammar
+      (module struct
+        [@@@ocaml.warning "-37"]
+
+        (** IGNORED *)
+        type t =
+          ([ `Clause0 of (unit[@tag "k0" = Atom "v0"]) (** first clause *)
+           | `Clause1 [@tag "k1" = Atom "v1"] (** second clause *)
+           ]
+          [@tag "kouter" = Atom "vouter"])
+        [@@deriving sexp_grammar ~tags_of_doc_comments]
+        (** IGNORED *)
+      end);
+    [%expect
+      {|
+      (Tagged (
+        (key   kouter)
+        (value vouter)
+        (grammar (
+          Variant (
+            (case_sensitivity Case_sensitive)
+            (clauses (
+              (Tag (
+                (key   sexp_grammar.doc_comment)
+                (value " first clause ")
+                (grammar (
+                  No_tag (
+                    (name Clause0)
+                    (clause_kind (
+                      List_clause (
+                        args (
+                          Cons
+                          (Tagged (
+                            (key   k0)
+                            (value v0)
+                            (grammar (List Empty))))
+                          Empty)))))))))
+              (Tag (
+                (key   sexp_grammar.doc_comment)
+                (value " second clause ")
+                (grammar (
+                  Tag (
+                    (key   k1)
+                    (value v1)
+                    (grammar (
+                      No_tag (
+                        (name        Clause1)
+                        (clause_kind Atom_clause))))))))))))))))
+      |}]
+  ;;
+
+  let%expect_test "doc comments - record fields" =
+    show_grammar
+      (module struct
+        (** IGNORED *)
+        type t =
+          { field0 : (unit[@tag "k0" = Atom "v0"]) (** first field *)
+          ; field1 : unit [@tag "k1" = Atom "v1"] (** second field *)
+          }
+        [@@deriving sexp_grammar ~tags_of_doc_comments]
+        (** IGNORED *)
+      end);
+    [%expect
+      {|
+      (List (
+        Fields (
+          (allow_extra_fields false)
+          (fields (
+            (Tag (
+              (key   sexp_grammar.doc_comment)
+              (value " first field ")
+              (grammar (
+                No_tag (
+                  (name     field0)
+                  (required true)
+                  (args (
+                    Cons
+                    (Tagged (
+                      (key   k0)
+                      (value v0)
+                      (grammar (List Empty))))
+                    Empty)))))))
+            (Tag (
+              (key   sexp_grammar.doc_comment)
+              (value " second field ")
+              (grammar (
+                Tag (
+                  (key   k1)
+                  (value v1)
+                  (grammar (
+                    No_tag (
+                      (name     field1)
+                      (required true)
+                      (args (Cons (List Empty) Empty)))))))))))))))
+      |}]
+  ;;
+
+  let%expect_test "deriving sexp_grammar without tags_of_doc_comments" =
+    show_grammar
+      (module struct
+        type t = { field : unit (** IGNORED *) } [@@deriving sexp_grammar]
+      end);
+    [%expect
+      {|
+      (List (
+        Fields (
+          (allow_extra_fields false)
+          (fields ((
+            No_tag (
+              (name     field)
+              (required true)
+              (args (Cons (List Empty) Empty)))))))))
+      |}]
+  ;;
+
+  let%expect_test "doc comments on subexpressions" =
+    show_grammar
+      (module struct
+        [@@@ocaml.warning "-37"]
+
+        type t = Foo of { bar : int (** inner *) } (** outer *)
+        [@@deriving sexp_grammar ~tags_of_doc_comments]
+      end);
+    [%expect
+      {|
+      (Variant (
+        (case_sensitivity Case_sensitive_except_first_character)
+        (clauses ((
+          Tag (
+            (key   sexp_grammar.doc_comment)
+            (value " outer ")
+            (grammar (
+              No_tag (
+                (name Foo)
+                (clause_kind (
+                  List_clause (
+                    args (
+                      Fields (
+                        (allow_extra_fields false)
+                        (fields ((
+                          Tag (
+                            (key   sexp_grammar.doc_comment)
+                            (value " inner ")
+                            (grammar (
+                              No_tag (
+                                (name     bar)
+                                (required true)
+                                (args (Cons Integer Empty)))))))))))))))))))))))
+      |}];
+    show_grammar
+      (module struct
+        [@@@ocaml.warning "-37"]
+
+        type t = [ `A of [ `B (** inner *) ] (** outer *) ]
+        [@@deriving sexp_grammar ~tags_of_doc_comments]
+      end);
+    [%expect
+      {|
+      (Variant (
+        (case_sensitivity Case_sensitive)
+        (clauses ((
+          Tag (
+            (key   sexp_grammar.doc_comment)
+            (value " outer ")
+            (grammar (
+              No_tag (
+                (name A)
+                (clause_kind (
+                  List_clause (
+                    args (
+                      Cons
+                      (Variant (
+                        (case_sensitivity Case_sensitive)
+                        (clauses ((
+                          Tag (
+                            (key   sexp_grammar.doc_comment)
+                            (value " inner ")
+                            (grammar (
+                              No_tag (
+                                (name        B)
+                                (clause_kind Atom_clause))))))))))
+                      Empty)))))))))))))
+      |}];
+    show_grammar
+      (module struct
+        [@@@ocaml.warning "-37"]
+
+        type t = { a : [ `B of int (** inner *) ] (** outer *) }
+        [@@deriving sexp_grammar ~tags_of_doc_comments]
+      end);
+    [%expect
+      {|
+      (List (
+        Fields (
+          (allow_extra_fields false)
+          (fields ((
+            Tag (
+              (key   sexp_grammar.doc_comment)
+              (value " outer ")
+              (grammar (
+                No_tag (
+                  (name     a)
+                  (required true)
+                  (args (
+                    Cons
+                    (Variant (
+                      (case_sensitivity Case_sensitive)
+                      (clauses ((
+                        Tag (
+                          (key   sexp_grammar.doc_comment)
+                          (value " inner ")
+                          (grammar (
+                            No_tag (
+                              (name B)
+                              (clause_kind (List_clause (args (Cons Integer Empty)))))))))))))
+                    Empty))))))))))))
+      |}];
+    show_grammar
+      (module struct
+        [@@@ocaml.warning "-37"]
+
+        type t = [ `A of [ `B (** inner *) ] option (** outer *) ]
+        [@@deriving sexp_grammar ~tags_of_doc_comments]
+      end);
+    [%expect
+      {|
+      (Variant (
+        (case_sensitivity Case_sensitive)
+        (clauses ((
+          Tag (
+            (key   sexp_grammar.doc_comment)
+            (value " outer ")
+            (grammar (
+              No_tag (
+                (name A)
+                (clause_kind (
+                  List_clause (
+                    args (
+                      Cons
+                      (Option (
+                        Variant (
+                          (case_sensitivity Case_sensitive)
+                          (clauses ((
+                            Tag (
+                              (key   sexp_grammar.doc_comment)
+                              (value " inner ")
+                              (grammar (
+                                No_tag (
+                                  (name        B)
+                                  (clause_kind Atom_clause)))))))))))
+                      Empty)))))))))))))
+      |}]
+  ;;
+end

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_tags.mli

@@ -0,0 +1 @@
+(* This interface intentionally left empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_tags.mlt

@@ -0,0 +1,62 @@
+open Ppx_sexp_conv_lib
+open Conv;;
+
+#verbose true
+
+module No_keys = struct
+  type t = (unit[@sexp_grammar.tag]) [@@deriving sexp_grammar]
+end
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: :: expected
+|}]
+
+module Key_literal_is_not_string = struct
+  type t = (unit[@sexp_grammar.tag 1 = [%sexp ""]]) [@@deriving sexp_grammar]
+end
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: This expression has type int but an expression was expected of type
+         string
+|}]
+
+module Key_ident_is_not_string = struct
+  let k = 1
+
+  type t = (unit[@sexp_grammar.tag k = [%sexp ""]]) [@@deriving sexp_grammar]
+end
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: This expression has type int but an expression was expected of type
+         string
+|}]
+
+module Value_literal_is_not_sexp = struct
+  type t = (unit[@sexp_grammar.tag "key" = 1]) [@@deriving sexp_grammar]
+end
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: This expression has type int but an expression was expected of type
+         Sexp.t
+|}]
+
+module Value_ident_is_not_sexp = struct
+  let v = 1
+
+  type t = (unit[@sexp_grammar.tag "key" = v]) [@@deriving sexp_grammar]
+end
+
+[%%expect
+  {|
+Line _, characters _-_:
+Error: This expression has type int but an expression was expected of type
+         Sexp.t
+|}]

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_test.ml

@@ -0,0 +1,86 @@
+open! Base
+
+module _ = struct
+  type t = int [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) = int_sexp_grammar
+  let _ = t_sexp_grammar
+
+  [@@@deriving.end]
+end
+
+module _ = struct
+  type 'a t = T of 'a
+  and 'a u = U of 'a t option [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : 'a t) -> ()
+  let _ = fun (_ : 'a u) -> ()
+
+  let t_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a t Sexplib0.Sexp_grammar.t =
+    fun _'a_sexp_grammar ->
+    { untyped =
+        Variant
+          { case_sensitivity = Case_sensitive_except_first_character
+          ; clauses =
+              [ No_tag
+                  { name = "T"
+                  ; clause_kind =
+                      List_clause { args = Cons (_'a_sexp_grammar.untyped, Empty) }
+                  }
+              ]
+          }
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  let u_sexp_grammar : 'a. 'a Sexplib0.Sexp_grammar.t -> 'a u Sexplib0.Sexp_grammar.t =
+    fun _'a_sexp_grammar ->
+    { untyped =
+        Variant
+          { case_sensitivity = Case_sensitive_except_first_character
+          ; clauses =
+              [ No_tag
+                  { name = "U"
+                  ; clause_kind =
+                      List_clause
+                        { args =
+                            Cons
+                              ( (option_sexp_grammar (t_sexp_grammar _'a_sexp_grammar))
+                                  .untyped
+                              , Empty )
+                        }
+                  }
+              ]
+          }
+    }
+  ;;
+
+  let _ = u_sexp_grammar
+
+  [@@@deriving.end]
+
+  (* Avoid unused constructor warnings. *)
+  let _ = T ()
+  let _ = U None
+end
+
+module _ = struct
+  type ('a, 'b) t = 'a -> 'b [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : ('a, 'b) t) -> ()
+
+  let t_sexp_grammar :
+        'a 'b.
+        'a Sexplib0.Sexp_grammar.t
+        -> 'b Sexplib0.Sexp_grammar.t
+        -> ('a, 'b) t Sexplib0.Sexp_grammar.t
+    =
+    fun _'a_sexp_grammar _'b_sexp_grammar -> Sexplib0.Sexp_conv.fun_sexp_grammar
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_test.mli

@@ -0,0 +1 @@
+(*_ This signature is deliberately empty. *)

unikernel/duniverse/ppx_sexp_conv/test/sexp_grammar/test_variants_more.ml

@@ -0,0 +1,93 @@
+open Base
+
+[@@@warning "-37"]
+
+module _ = struct
+  type t = A of [ `A of int ] [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (Variant
+               { case_sensitivity = Case_sensitive_except_first_character
+               ; clauses =
+                   [ No_tag
+                       { name = "A"
+                       ; clause_kind =
+                           List_clause
+                             { args =
+                                 Cons
+                                   ( Variant
+                                       { case_sensitivity = Case_sensitive
+                                       ; clauses =
+                                           [ No_tag
+                                               { name = "A"
+                                               ; clause_kind =
+                                                   List_clause
+                                                     { args =
+                                                         Cons
+                                                           ( int_sexp_grammar.untyped
+                                                           , Empty )
+                                                     }
+                                               }
+                                           ]
+                                       }
+                                   , Empty )
+                             }
+                       }
+                   ]
+               }))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end
+
+module _ = struct
+  type t = { a : [ `A of int ] } [@@deriving_inline sexp_grammar]
+
+  let _ = fun (_ : t) -> ()
+
+  let (t_sexp_grammar : t Sexplib0.Sexp_grammar.t) =
+    { untyped =
+        Lazy
+          (lazy
+            (List
+               (Fields
+                  { allow_extra_fields = false
+                  ; fields =
+                      [ No_tag
+                          { name = "a"
+                          ; required = true
+                          ; args =
+                              Cons
+                                ( Variant
+                                    { case_sensitivity = Case_sensitive
+                                    ; clauses =
+                                        [ No_tag
+                                            { name = "A"
+                                            ; clause_kind =
+                                                List_clause
+                                                  { args =
+                                                      Cons
+                                                        (int_sexp_grammar.untyped, Empty)
+                                                  }
+                                            }
+                                        ]
+                                    }
+                                , Empty )
+                          }
+                      ]
+                  })))
+    }
+  ;;
+
+  let _ = t_sexp_grammar
+
+  [@@@end]
+end