diff --git a/otherlibs/dune-build-info/test/run.t b/otherlibs/dune-build-info/test/run.t
old mode 100755
new mode 100644
index b83081602d8..91b2ce55968
--- a/otherlibs/dune-build-info/test/run.t
+++ b/otherlibs/dune-build-info/test/run.t
@@ -132,7 +132,7 @@ craft an example with a single placeholder to make the output stable:
   $ dune build d/d.install
   $ dune install d --prefix _install --debug-artifact-substitution
   Found placeholder in _build/install/default/bin/d:
-  - placeholder: Vcs_describe In_source_tree "d"
+  - placeholder: Vcs_describe (In_source_tree "d")
   - evaluates to: "1.0+d"
 
 Test substitution when promoting
diff --git a/otherlibs/dyn/dyn.ml b/otherlibs/dyn/dyn.ml
index e06b2f872f3..b9a22524f57 100644
--- a/otherlibs/dyn/dyn.ml
+++ b/otherlibs/dyn/dyn.ml
@@ -68,12 +68,14 @@ let pp_sequence start stop x ~f =
     let sep = ";" ^ String.make (String.length start) ' ' in
     Pp.hvbox
       (Pp.concat_mapi ~sep:Pp.cut x ~f:(fun i x ->
-         Pp.box ((if i = 0 then Pp.verbatim (start ^ " ") else Pp.verbatim sep) ++ f x))
+         Pp.box
+           ~indent:2
+           ((if i = 0 then Pp.verbatim (start ^ " ") else Pp.verbatim sep) ++ f x))
        ++ Pp.space
        ++ Pp.verbatim stop)
 ;;
 
-let rec pp =
+let rec pp ?(in_arg = false) =
   let open Pp.O in
   function
   | Opaque -> Pp.verbatim "<opaque>"
@@ -87,8 +89,8 @@ let rec pp =
   | Bytes b -> string_in_ocaml_syntax (Bytes.to_string b)
   | Char c -> Pp.char c
   | Float f -> Pp.verbatim (string_of_float f)
-  | Option None -> pp (Variant ("None", []))
-  | Option (Some x) -> pp (Variant ("Some", [ x ]))
+  | Option None -> pp ~in_arg (Variant ("None", []))
+  | Option (Some x) -> pp ~in_arg (Variant ("Some", [ x ]))
   | List xs -> pp_sequence "[" "]" xs ~f:pp
   | Array xs -> pp_sequence "[|" "|]" (Array.to_list xs) ~f:pp
   | Set xs ->
@@ -100,25 +102,25 @@ let rec pp =
        ++ Pp.space
        ++ pp_sequence "{" "}" xs ~f:(fun (k, v) ->
          Pp.box ~indent:2 (pp k ++ Pp.space ++ Pp.char ':' ++ Pp.space ++ pp v)))
-  | Tuple x ->
-    Pp.box
-      (Pp.char '('
-       ++ Pp.concat_map ~sep:(Pp.seq (Pp.char ',') Pp.space) x ~f:pp
-       ++ Pp.char ')')
+  | Tuple xs ->
+    Pp.char '('
+    ++ Pp.hvbox (Pp.concat_map ~sep:(Pp.seq (Pp.char ',') Pp.space) xs ~f:pp)
+    ++ Pp.char ')'
   | Record fields ->
     pp_sequence "{" "}" fields ~f:(fun (f, v) ->
       Pp.box ~indent:2 (Pp.verbatim f ++ Pp.space ++ Pp.char '=' ++ Pp.space ++ pp v))
   | Variant (v, []) -> Pp.verbatim v
-  | Variant (v, xs) ->
-    Pp.hvbox
-      ~indent:2
-      (Pp.concat
-         [ Pp.verbatim v
-         ; Pp.space
-         ; Pp.concat_map ~sep:(Pp.seq (Pp.char ',') Pp.space) xs ~f:pp
-         ])
+  | Variant (v, (_ :: _ as xs)) ->
+    let arg =
+      match xs with
+      | [ x ] -> x
+      | _ -> Tuple xs
+    in
+    let app = Pp.hvbox ~indent:2 (Pp.verbatim v ++ Pp.space ++ pp ~in_arg:true arg) in
+    if in_arg then Pp.char '(' ++ app ++ Pp.char ')' else app
 ;;
 
+let pp t = pp t
 let to_string t = Format.asprintf "%a" Pp.to_fmt (pp t)
 
 type 'a builder = 'a -> t
diff --git a/otherlibs/ocamlc-loc/test/ocamlc_loc_tests.ml b/otherlibs/ocamlc-loc/test/ocamlc_loc_tests.ml
index 7b6d6363e6d..10070c42498 100644
--- a/otherlibs/ocamlc-loc/test/ocamlc_loc_tests.ml
+++ b/otherlibs/ocamlc-loc/test/ocamlc_loc_tests.ml
@@ -64,7 +64,7 @@ Error (warning 32 [unused-value-declaration]): unused value foo.
     { loc = { path = "test.ml"; line = Single 1; chars = Some (4, 7) }
     ; message = "unused value foo."
     ; related = []
-    ; severity = Error Some { code = 32; name = "unused-value-declaration" }
+    ; severity = Error (Some { code = 32; name = "unused-value-declaration" })
     } |}]
 ;;
 
@@ -98,9 +98,9 @@ Error: The implementation test.ml does not match the interface test.cmi:
          The type bool is not compatible with the type int"
     ; related =
         [ ({ path = "test.mli"; line = Single 1; chars = Some (0, 11) },
-          "Expected declaration")
+           "Expected declaration")
         ; ({ path = "test.ml"; line = Single 1; chars = Some (4, 5) },
-          "Actual declaration")
+           "Actual declaration")
         ]
     ; severity = Error None
     } |}]
@@ -169,7 +169,7 @@ Error: Signature mismatch:
   [%expect
     {|
     >> error 0
-    { loc = { path = "test.ml"; line = Range 3, 5; chars = Some (6, 3) }
+    { loc = { path = "test.ml"; line = Range (3, 5); chars = Some (6, 3) }
     ; message =
         "Signature mismatch:\n\
          Modules do not match:\n\
@@ -184,9 +184,9 @@ Error: Signature mismatch:
          Type float is not compatible with type int"
     ; related =
         [ ({ path = "test.ml"; line = Single 2; chars = Some (2, 20) },
-          "Expected declaration")
+           "Expected declaration")
         ; ({ path = "test.ml"; line = Single 4; chars = Some (6, 7) },
-          "Actual declaration")
+           "Actual declaration")
         ]
     ; severity = Error None
     } |}]
@@ -242,12 +242,12 @@ Error: The implementation src/dune_rules/artifacts.ml
            ; line = Single 20
            ; chars = Some (4, 33)
            },
-          "Expected declaration")
+           "Expected declaration")
         ; ({ path = "src/dune_rules/artifacts.ml"
            ; line = Single 50
            ; chars = Some (8, 13)
            },
-          "Actual declaration")
+           "Actual declaration")
         ]
     ; severity = Error None
     } |}]
@@ -280,7 +280,7 @@ Will be removed past 2020-20-20. Use Mylib.Intf_only instead.
         "module Bar\n\
          Will be removed past 2020-20-20. Use Mylib.Bar instead."
     ; related = []
-    ; severity = Error Some "deprecated"
+    ; severity = Error (Some "deprecated")
     }
     >> error 1
     { loc = { path = "fooexe.ml"; line = Single 4; chars = Some (0, 7) }
@@ -288,7 +288,7 @@ Will be removed past 2020-20-20. Use Mylib.Intf_only instead.
         "module Foo\n\
          Will be removed past 2020-20-20. Use Mylib.Foo instead."
     ; related = []
-    ; severity = Error Some "deprecated"
+    ; severity = Error (Some "deprecated")
     }
     >> error 2
     { loc = { path = "fooexe.ml"; line = Single 7; chars = Some (11, 22) }
@@ -296,7 +296,7 @@ Will be removed past 2020-20-20. Use Mylib.Intf_only instead.
         "module Intf_only\n\
          Will be removed past 2020-20-20. Use Mylib.Intf_only instead."
     ; related = []
-    ; severity = Error Some "deprecated"
+    ; severity = Error (Some "deprecated")
     } |}]
 ;;
 
@@ -315,7 +315,7 @@ Error: Some record fields are undefined: signal_watcher
     >> error 0
     { loc =
         { path = "test/expect-tests/timer_tests.ml"
-        ; line = Range 6, 10
+        ; line = Range (6, 10)
         ; chars = Some (2, 3)
         }
     ; message = "Some record fields are undefined: signal_watcher"
@@ -387,7 +387,7 @@ Error: The implementation src/dune_engine/build_system.ml
            ; line = Single 8
            ; chars = Some (0, 40)
            },
-          "Expected declaration")
+           "Expected declaration")
         ]
     ; severity = Error None
     } |}]
@@ -503,7 +503,7 @@ testing
     ; message = "A.f\n\
                  testing"
     ; related = []
-    ; severity = Error Some "foobar"
+    ; severity = Error (Some "foobar")
     } |}]
 ;;
 
@@ -572,7 +572,7 @@ Case
     >> error 0
     { loc =
         { path = "src/dune_engine/action.ml"
-        ; line = Range 34, 96
+        ; line = Range (34, 96)
         ; chars = Some (4, 64)
         }
     ; message =
@@ -580,12 +580,12 @@ Case
          Here is an example of a case that is not matched:\n\
          Case"
     ; related = []
-    ; severity = Error Some { code = 8; name = "partial-match" }
+    ; severity = Error (Some { code = 8; name = "partial-match" })
     }
     >> error 1
     { loc =
         { path = "src/dune_engine/action.ml"
-        ; line = Range 291, 315
+        ; line = Range (291, 315)
         ; chars = Some (2, 22)
         }
     ; message =
@@ -593,12 +593,12 @@ Case
          Here is an example of a case that is not matched:\n\
          Case"
     ; related = []
-    ; severity = Error Some { code = 8; name = "partial-match" }
+    ; severity = Error (Some { code = 8; name = "partial-match" })
     }
     >> error 2
     { loc =
         { path = "src/dune_engine/action.ml"
-        ; line = Range 339, 363
+        ; line = Range (339, 363)
         ; chars = Some (21, 24)
         }
     ; message =
@@ -606,12 +606,12 @@ Case
          Here is an example of a case that is not matched:\n\
          Case"
     ; related = []
-    ; severity = Error Some { code = 8; name = "partial-match" }
+    ; severity = Error (Some { code = 8; name = "partial-match" })
     }
     >> error 3
     { loc =
         { path = "src/dune_engine/action.ml"
-        ; line = Range 391, 414
+        ; line = Range (391, 414)
         ; chars = Some (4, 70)
         }
     ; message =
@@ -619,7 +619,7 @@ Case
          Here is an example of a case that is not matched:\n\
          Case"
     ; related = []
-    ; severity = Error Some { code = 8; name = "partial-match" }
+    ; severity = Error (Some { code = 8; name = "partial-match" })
     } |}]
 ;;
 
diff --git a/otherlibs/stdune/test/ansi_color_tests.ml b/otherlibs/stdune/test/ansi_color_tests.ml
index 4e99445e9ca..540a4eb0325 100644
--- a/otherlibs/stdune/test/ansi_color_tests.ml
+++ b/otherlibs/stdune/test/ansi_color_tests.ml
@@ -53,48 +53,60 @@ let%expect_test "reproduce #2664" =
   [%expect
     {|
     Vbox
-      0,
-      Seq
-        Seq
-          Seq
-            Seq
-              Seq
-                Seq
-                  Seq
-                    Seq
-                      Seq
-                        Seq
-                          Seq
-                            Seq
-                              Seq
-                                Seq
-                                  Seq
-                                    Seq
-                                      Seq
-                                        Seq
-                                          Seq
-                                            Seq
-                                              Nop,
-                                              Tag [ Fg_blue ], Verbatim "1",
-                                            Tag [ Fg_blue ], Verbatim "2",
-                                          Tag [ Fg_blue ], Verbatim "3",
-                                        Tag [ Fg_blue ], Verbatim "4",
-                                      Tag [ Fg_blue ], Verbatim "5",
-                                    Tag [ Fg_blue ], Verbatim "6",
-                                  Tag [ Fg_blue ], Verbatim "7",
-                                Tag [ Fg_blue ], Verbatim "8",
-                              Tag [ Fg_blue ], Verbatim "9",
-                            Tag [ Fg_blue ], Verbatim "10",
-                          Tag [ Fg_blue ], Verbatim "11",
-                        Tag [ Fg_blue ], Verbatim "12",
-                      Tag [ Fg_blue ], Verbatim "13",
-                    Tag [ Fg_blue ], Verbatim "14",
-                  Tag [ Fg_blue ], Verbatim "15",
-                Tag [ Fg_blue ], Verbatim "16",
-              Tag [ Fg_blue ], Verbatim "17",
-            Tag [ Fg_blue ], Verbatim "18",
-          Tag [ Fg_blue ], Verbatim "19",
-        Tag [ Fg_blue ], Verbatim "20" |}]
+      (0,
+       Seq
+         (Seq
+            (Seq
+               (Seq
+                  (Seq
+                     (Seq
+                        (Seq
+                           (Seq
+                              (Seq
+                                 (Seq
+                                    (Seq
+                                       (Seq
+                                          (Seq
+                                             (Seq
+                                                (Seq
+                                                   (Seq
+                                                      (Seq
+                                                         (Seq
+                                                            (Seq
+                                                               (Seq
+                                                                  (Nop,
+                                                                   Tag
+                                                                     ([ Fg_blue ],
+                                                                      Verbatim
+                                                                        "1")),
+                                                                Tag
+                                                                  ([ Fg_blue ],
+                                                                   Verbatim "2")),
+                                                             Tag
+                                                               ([ Fg_blue ],
+                                                                Verbatim "3")),
+                                                          Tag
+                                                            ([ Fg_blue ],
+                                                             Verbatim "4")),
+                                                       Tag
+                                                         ([ Fg_blue ],
+                                                          Verbatim "5")),
+                                                    Tag
+                                                      ([ Fg_blue ], Verbatim "6")),
+                                                 Tag ([ Fg_blue ], Verbatim "7")),
+                                              Tag ([ Fg_blue ], Verbatim "8")),
+                                           Tag ([ Fg_blue ], Verbatim "9")),
+                                        Tag ([ Fg_blue ], Verbatim "10")),
+                                     Tag ([ Fg_blue ], Verbatim "11")),
+                                  Tag ([ Fg_blue ], Verbatim "12")),
+                               Tag ([ Fg_blue ], Verbatim "13")),
+                            Tag ([ Fg_blue ], Verbatim "14")),
+                         Tag ([ Fg_blue ], Verbatim "15")),
+                      Tag ([ Fg_blue ], Verbatim "16")),
+                   Tag ([ Fg_blue ], Verbatim "17")),
+                Tag ([ Fg_blue ], Verbatim "18")),
+             Tag ([ Fg_blue ], Verbatim "19")),
+          Tag ([ Fg_blue ], Verbatim "20"))) |}]
 ;;
 
 let%expect_test "Ansi_color.strip" =
@@ -129,30 +141,30 @@ let%expect_test "parse fg and bg colors" =
   [%expect
     {|
 Vbox
-  0,
-  Seq
-    Seq
-      Seq
-        Seq
-          Seq
-            Seq
-              Seq
-                Seq
-                  Seq
-                    Seq
-                      Seq
-                        Seq Nop, Verbatim "This is a ",
-                        Tag [ Fg_blue ], Verbatim "blue",
-                      Verbatim " string with ",
-                    Tag [ Fg_red ], Verbatim "red",
-                  Verbatim " and ",
-                Tag [ Fg_green ], Verbatim "green",
-              Verbatim " together with strings of a ",
-            Tag [ Bg_blue ], Verbatim "blue blackground",
-          Verbatim " and ",
-        Tag [ Bg_red ], Verbatim "red background",
-      Verbatim " and ",
-    Tag [ Bg_green ], Verbatim "green background" |}]
+  (0,
+   Seq
+     (Seq
+        (Seq
+           (Seq
+              (Seq
+                 (Seq
+                    (Seq
+                       (Seq
+                          (Seq
+                             (Seq
+                                (Seq
+                                   (Seq (Nop, Verbatim "This is a "),
+                                    Tag ([ Fg_blue ], Verbatim "blue")),
+                                 Verbatim " string with "),
+                              Tag ([ Fg_red ], Verbatim "red")),
+                           Verbatim " and "),
+                        Tag ([ Fg_green ], Verbatim "green")),
+                     Verbatim " together with strings of a "),
+                  Tag ([ Bg_blue ], Verbatim "blue blackground")),
+               Verbatim " and "),
+            Tag ([ Bg_red ], Verbatim "red background")),
+         Verbatim " and "),
+      Tag ([ Bg_green ], Verbatim "green background"))) |}]
 ;;
 
 let%expect_test "parse multiple fg and bg colors" =
@@ -167,14 +179,18 @@ let%expect_test "parse multiple fg and bg colors" =
   [%expect
     {|
 Vbox
-  0,
-  Seq
-    Seq
-      Seq
-        Seq Nop, Verbatim "This text is ",
-        Tag [ Fg_blue; Bg_red ], Verbatim "blue string with a red background",
-      Verbatim " and ",
-    Tag [ Fg_green; Bg_blue ], Verbatim "green string with a blue background" |}]
+  (0,
+   Seq
+     (Seq
+        (Seq
+           (Seq (Nop, Verbatim "This text is "),
+            Tag
+              ([ Fg_blue; Bg_red ],
+               Verbatim "blue string with a red background")),
+         Verbatim " and "),
+      Tag
+        ([ Fg_green; Bg_blue ],
+         Verbatim "green string with a blue background"))) |}]
 ;;
 
 let%expect_test "fg default overrides" =
@@ -189,14 +205,14 @@ let%expect_test "fg default overrides" =
   [%expect
     {|
   Vbox
-    0,
-    Seq
-      Seq
-        Seq
-          Seq Nop, Verbatim "This text has a ",
-          Tag [ Fg_blue ], Verbatim "blue foreground",
-        Verbatim " but here it becomes the default foreground,",
-      Verbatim " even together with another foreground modifier." |}]
+    (0,
+     Seq
+       (Seq
+          (Seq
+             (Seq (Nop, Verbatim "This text has a "),
+              Tag ([ Fg_blue ], Verbatim "blue foreground")),
+           Verbatim " but here it becomes the default foreground,"),
+        Verbatim " even together with another foreground modifier.")) |}]
 ;;
 
 let%expect_test "bg default overrides" =
@@ -211,14 +227,14 @@ let%expect_test "bg default overrides" =
   [%expect
     {|
 Vbox
-  0,
-  Seq
-    Seq
-      Seq
-        Seq Nop, Verbatim "This text has a ",
-        Tag [ Bg_blue ], Verbatim "blue background",
-      Verbatim " but here it becomes the default background,",
-    Verbatim " even together with another background modifier." |}]
+  (0,
+   Seq
+     (Seq
+        (Seq
+           (Seq (Nop, Verbatim "This text has a "),
+            Tag ([ Bg_blue ], Verbatim "blue background")),
+         Verbatim " but here it becomes the default background,"),
+      Verbatim " even together with another background modifier.")) |}]
 ;;
 
 let%expect_test "parse 8-bit colors" =
@@ -235,30 +251,31 @@ let%expect_test "parse 8-bit colors" =
   [%expect
     {|
 Vbox
-  0,
-  Seq
-    Seq
-      Seq
-        Seq
-          Seq
-            Seq
-              Seq
-                Seq
-                  Seq
-                    Seq
-                      Seq
-                        Seq Nop, Verbatim "This is a ",
-                        Tag [ Fg_8_bit_color 33 ], Verbatim "blue",
-                      Verbatim " string with ",
-                    Tag [ Fg_8_bit_color 196 ], Verbatim "red",
-                  Verbatim " and ",
-                Tag [ Fg_8_bit_color 46 ], Verbatim "green",
-              Verbatim " together with strings of a ",
-            Tag [ Bg_8_bit_color 33 ], Verbatim "blue blackground",
-          Verbatim " and ",
-        Tag [ Bg_8_bit_color 196 ], Verbatim "red background",
-      Verbatim " and ",
-    Tag [ Bg_8_bit_color 46 ], Verbatim "green background" |}]
+  (0,
+   Seq
+     (Seq
+        (Seq
+           (Seq
+              (Seq
+                 (Seq
+                    (Seq
+                       (Seq
+                          (Seq
+                             (Seq
+                                (Seq
+                                   (Seq (Nop, Verbatim "This is a "),
+                                    Tag
+                                      ([ Fg_8_bit_color 33 ], Verbatim "blue")),
+                                 Verbatim " string with "),
+                              Tag ([ Fg_8_bit_color 196 ], Verbatim "red")),
+                           Verbatim " and "),
+                        Tag ([ Fg_8_bit_color 46 ], Verbatim "green")),
+                     Verbatim " together with strings of a "),
+                  Tag ([ Bg_8_bit_color 33 ], Verbatim "blue blackground")),
+               Verbatim " and "),
+            Tag ([ Bg_8_bit_color 196 ], Verbatim "red background")),
+         Verbatim " and "),
+      Tag ([ Bg_8_bit_color 46 ], Verbatim "green background"))) |}]
 ;;
 
 let%expect_test "parse 24-bit colors" =
@@ -275,33 +292,38 @@ let%expect_test "parse 24-bit colors" =
   [%expect
     {|
     Vbox
-      0,
-      Seq
-        Seq
-          Seq
-            Seq
-              Seq
-                Seq
-                  Seq
-                    Seq
-                      Seq
-                        Seq
-                          Seq
-                            Seq Nop, Verbatim "This is a ",
+      (0,
+       Seq
+         (Seq
+            (Seq
+               (Seq
+                  (Seq
+                     (Seq
+                        (Seq
+                           (Seq
+                              (Seq
+                                 (Seq
+                                    (Seq
+                                       (Seq (Nop, Verbatim "This is a "),
+                                        Tag
+                                          ([ Fg_24_bit_color [ 255; 0; 0 ] ],
+                                           Verbatim "blue")),
+                                     Verbatim " string with "),
+                                  Tag
+                                    ([ Fg_24_bit_color [ 0; 255; 0 ] ],
+                                     Verbatim "red")),
+                               Verbatim " and "),
                             Tag
-                              [ Fg_24_bit_color [ 255; 0; 0 ] ],
-                              Verbatim "blue",
-                          Verbatim " string with ",
-                        Tag [ Fg_24_bit_color [ 0; 255; 0 ] ], Verbatim "red",
-                      Verbatim " and ",
-                    Tag [ Fg_24_bit_color [ 0; 0; 255 ] ], Verbatim "green",
-                  Verbatim " together with strings of a ",
+                              ([ Fg_24_bit_color [ 0; 0; 255 ] ],
+                               Verbatim "green")),
+                         Verbatim " together with strings of a "),
+                      Tag
+                        ([ Bg_24_bit_color [ 255; 0; 0 ] ],
+                         Verbatim "blue blackground")),
+                   Verbatim " and "),
                 Tag
-                  [ Bg_24_bit_color [ 255; 0; 0 ] ],
-                  Verbatim "blue blackground",
-              Verbatim " and ",
-            Tag [ Bg_24_bit_color [ 0; 255; 0 ] ], Verbatim "red background",
-          Verbatim " and ",
-        Tag [ Bg_24_bit_color [ 0; 0; 255 ] ], Verbatim "green background"
+                  ([ Bg_24_bit_color [ 0; 255; 0 ] ], Verbatim "red background")),
+             Verbatim " and "),
+          Tag ([ Bg_24_bit_color [ 0; 0; 255 ] ], Verbatim "green background")))
 |}]
 ;;
diff --git a/otherlibs/stdune/test/path_tests.ml b/otherlibs/stdune/test/path_tests.ml
index 27b9d915138..c8db7d45e61 100644
--- a/otherlibs/stdune/test/path_tests.ml
+++ b/otherlibs/stdune/test/path_tests.ml
@@ -43,7 +43,7 @@ let%expect_test _ =
   let p = Path.(relative root) "foo" in
   descendant p ~of_:p;
   [%expect {|
-  Some In_source_tree "."
+  Some (In_source_tree ".")
   |}]
 ;;
 
@@ -149,21 +149,21 @@ false
 let%expect_test _ =
   descendant (r "foo") ~of_:(r "foo/");
   [%expect {|
-Some In_source_tree "."
+Some (In_source_tree ".")
 |}]
 ;;
 
 let%expect_test _ =
   descendant (r "foo/") ~of_:(r "foo");
   [%expect {|
-Some In_source_tree "."
+Some (In_source_tree ".")
 |}]
 ;;
 
 let%expect_test _ =
   descendant (r "foo/bar") ~of_:(r "foo");
   [%expect {|
-Some In_source_tree "bar"
+Some (In_source_tree "bar")
 |}]
 ;;
 
@@ -177,14 +177,14 @@ None
 let%expect_test _ =
   descendant Path.root ~of_:Path.root;
   [%expect {|
-Some In_source_tree "."
+Some (In_source_tree ".")
 |}]
 ;;
 
 let%expect_test _ =
   descendant (r "foo") ~of_:Path.root;
   [%expect {|
-Some In_source_tree "foo"
+Some (In_source_tree "foo")
 |}]
 ;;
 
@@ -205,21 +205,21 @@ None
 let%expect_test _ =
   descendant (Path.relative build_dir "foo/bar") ~of_:build_dir;
   [%expect {|
-Some In_source_tree "foo/bar"
+Some (In_source_tree "foo/bar")
 |}]
 ;;
 
 let%expect_test _ =
   descendant (Path.relative build_dir "foo/bar") ~of_:(Path.relative build_dir "foo");
   [%expect {|
-Some In_source_tree "bar"
+Some (In_source_tree "bar")
 |}]
 ;;
 
 let%expect_test _ =
   descendant (Path.relative build_dir "foo/bar") ~of_:(Path.relative build_dir "foo");
   [%expect {|
-Some In_source_tree "bar"
+Some (In_source_tree "bar")
 |}]
 ;;
 
@@ -453,13 +453,13 @@ let%expect_test _ =
 [@@expect.uncaught_exn
   {|
   ( "(\"Path.rm_rf called on external dir\",\
-   \n{ t = External \"/does/not/exist/foo/bar/baz\" })") |}]
+   \n { t = External \"/does/not/exist/foo/bar/baz\" })") |}]
 ;;
 
 let%expect_test _ =
   drop_build_context (Path.relative Path.build_dir "foo/bar");
   [%expect {|
-Some In_source_tree "bar"
+Some (In_source_tree "bar")
 |}]
 ;;
 
diff --git a/test/blackbox-tests/test-cases/directory-targets/copy-files.t b/test/blackbox-tests/test-cases/directory-targets/copy-files.t
index 2f13c365280..ca151fd6a20 100644
--- a/test/blackbox-tests/test-cases/directory-targets/copy-files.t
+++ b/test/blackbox-tests/test-cases/directory-targets/copy-files.t
@@ -25,7 +25,7 @@ Dune loads all the rules of a directory at once.
   Error: Dependency cycle between:
      Computing directory contents of _build/default
   -> { dir = In_build_dir "default/foo"
-     ; predicate = Glob Glob "*"
+     ; predicate = Glob (Glob "*")
      ; only_generated_files = false
      }
   -> Computing directory contents of _build/default
diff --git a/test/blackbox-tests/test-cases/enabled_if/eif-dune-describe-crash.t b/test/blackbox-tests/test-cases/enabled_if/eif-dune-describe-crash.t
index fc27c378570..273b7a7a82a 100644
--- a/test/blackbox-tests/test-cases/enabled_if/eif-dune-describe-crash.t
+++ b/test/blackbox-tests/test-cases/enabled_if/eif-dune-describe-crash.t
@@ -28,5 +28,5 @@
   Internal error, please report upstream including the contents of _build/log.
   Description:
     ("modules_and_obj_dir: failed lookup",
-    { keys = []; for_ = Exe { first_exe = "test" } })
+     { keys = []; for_ = Exe { first_exe = "test" } })
   Raised at Stdune__Code_error.raise in file
diff --git a/test/blackbox-tests/test-cases/github7806.t b/test/blackbox-tests/test-cases/github7806.t
index 06c90074426..2fae64f46cd 100644
--- a/test/blackbox-tests/test-cases/github7806.t
+++ b/test/blackbox-tests/test-cases/github7806.t
@@ -2,8 +2,8 @@
   Internal error, please report upstream including the contents of _build/log.
   Description:
     ("[as_in_source_tree_exn] called on something not in source tree",
-    { t =
-        External
-          "$TESTCASE_ROOT"
-    })
+     { t =
+         External
+           "$TESTCASE_ROOT"
+     })
   Raised at Stdune__Code_error.raise in file
diff --git a/test/blackbox-tests/test-cases/invalid-opam-file-name-github8281.t b/test/blackbox-tests/test-cases/invalid-opam-file-name-github8281.t
index 0948b756b61..503cd36f925 100644
--- a/test/blackbox-tests/test-cases/invalid-opam-file-name-github8281.t
+++ b/test/blackbox-tests/test-cases/invalid-opam-file-name-github8281.t
@@ -27,14 +27,14 @@ Whenever an invalid package name is used, dune crashes when building @doc
   Internal error, please report upstream including the contents of _build/log.
   Description:
     ("[gen_rules] returned rules in a directory that is not a descendant of the directory it was called for",
-    { dir = In_build_dir "default/_doc/_html/x.y"
-    ; example =
-        Rule
-          { targets =
-              { root = In_build_dir "default/_doc/_html/x"
-              ; files = set { "db.js" }
-              ; dirs = set {}
-              }
-          }
-    })
+     { dir = In_build_dir "default/_doc/_html/x.y"
+     ; example =
+         Rule
+           { targets =
+               { root = In_build_dir "default/_doc/_html/x"
+               ; files = set { "db.js" }
+               ; dirs = set {}
+               }
+           }
+     })
   Raised at Stdune__Code_error.raise in file
diff --git a/test/blackbox-tests/test-cases/menhir/flags-in-workspace.t b/test/blackbox-tests/test-cases/menhir/flags-in-workspace.t
index 5dac8a83873..8f16dba1939 100644
--- a/test/blackbox-tests/test-cases/menhir/flags-in-workspace.t
+++ b/test/blackbox-tests/test-cases/menhir/flags-in-workspace.t
@@ -16,5 +16,5 @@ See #9024.
   Internal error, please report upstream including the contents of _build/log.
   Description:
     ("Syntax identifier is unset",
-    { name = "menhir"
-    ; supported_versions =
+     { name = "menhir"
+     ; supported_versions =
diff --git a/test/blackbox-tests/test-cases/pkg/external-lock-dir.t b/test/blackbox-tests/test-cases/pkg/external-lock-dir.t
index b9974fee5fb..61cc4f99cd2 100644
--- a/test/blackbox-tests/test-cases/pkg/external-lock-dir.t
+++ b/test/blackbox-tests/test-cases/pkg/external-lock-dir.t
@@ -17,8 +17,8 @@ A lock directory which does not exist in the source tree:
   Internal error, please report upstream including the contents of _build/log.
   Description:
     ("Local.relative: received absolute path",
-    { t = "."
-    ; path =
-        "$TESTCASE_ROOT/dune.lock"
-    })
+     { t = "."
+     ; path =
+         "$TESTCASE_ROOT/dune.lock"
+     })
   Raised at Stdune__Code_error.raise in file
diff --git a/test/blackbox-tests/test-cases/version-corruption.t b/test/blackbox-tests/test-cases/version-corruption.t
index 93156474483..1b90c8cd85f 100644
--- a/test/blackbox-tests/test-cases/version-corruption.t
+++ b/test/blackbox-tests/test-cases/version-corruption.t
@@ -116,10 +116,10 @@ which corresponds to `~min_len` in Link_time_code_gen.
 
   $ dune build --debug-artifact-substitution
   Found placeholder in _build/default/gen_lifecycle.exe:
-  - placeholder: Vcs_describe In_source_tree "."
+  - placeholder: Vcs_describe (In_source_tree ".")
   - evaluates to: "v0.0.1"
   Found placeholder in _build/default/gen_lifecycle.bc:
-  - placeholder: Vcs_describe In_source_tree "."
+  - placeholder: Vcs_describe (In_source_tree ".")
   - evaluates to: "v0.0.1"
 
   $ ocaml compare.ml gen_lifecycle.old ./gen_lifecycle.exe
diff --git a/test/expect-tests/dune_lang/sexp_tests.ml b/test/expect-tests/dune_lang/sexp_tests.ml
index eb75ac478c2..2201760a264 100644
--- a/test/expect-tests/dune_lang/sexp_tests.ml
+++ b/test/expect-tests/dune_lang/sexp_tests.ml
@@ -308,7 +308,8 @@ let%expect_test _ =
    \n ; start = { pos_lnum = 1; pos_bol = 0; pos_cnum = 0 }\
    \n ; stop = { pos_lnum = 1; pos_bol = 0; pos_cnum = 0 }\
    \n },\
-   \n\"Invalid text in unquoted template\", { s = \"x%{\" })") |}]
+   \n \"Invalid text in unquoted template\",\
+   \n { s = \"x%{\" })") |}]
 ;;
 
 let%expect_test _ =
@@ -320,7 +321,8 @@ let%expect_test _ =
    \n ; start = { pos_lnum = 1; pos_bol = 0; pos_cnum = 0 }\
    \n ; stop = { pos_lnum = 1; pos_bol = 0; pos_cnum = 0 }\
    \n },\
-   \n\"Invalid text in unquoted template\", { s = \"x%{\" })") |}]
+   \n \"Invalid text in unquoted template\",\
+   \n { s = \"x%{\" })") |}]
 ;;
 
 let%expect_test _ =
@@ -358,11 +360,11 @@ world
   |> print_dyn;
   [%expect
     {|
-[ Atom A "hello"
+[ Atom (A "hello")
 ; Comment [ " comment" ]
-; Atom A "world"
+; Atom (A "world")
 ; Comment [ " multiline"; " comment" ]
-; List [ Atom A "x"; Comment [ " comment inside list" ]; Atom A "y" ]
+; List [ Atom (A "x"); Comment [ " comment inside list" ]; Atom (A "y") ]
 ]
 |}]
 ;;
diff --git a/test/expect-tests/dune_pkg/dune_pkg_unit_tests.ml b/test/expect-tests/dune_pkg/dune_pkg_unit_tests.ml
index 40a5b1c1733..24fa1953aa1 100644
--- a/test/expect-tests/dune_pkg/dune_pkg_unit_tests.ml
+++ b/test/expect-tests/dune_pkg/dune_pkg_unit_tests.ml
@@ -303,7 +303,7 @@ let%expect_test "encode/decode round trip test for lockdir with complex deps" =
     ; packages =
         map
           { "a" :
-              { build_command = Some Action [ "progn"; [ "echo"; "hello" ] ]
+              { build_command = Some (Action [ "progn"; [ "echo"; "hello" ] ])
               ; install_command = Some [ "system"; "echo 'world'" ]
               ; depends = []
               ; info =
diff --git a/test/expect-tests/dune_rpc_impl/dune_rpc_impl_tests.ml b/test/expect-tests/dune_rpc_impl/dune_rpc_impl_tests.ml
index 71ab5e1c0f5..30c86d38b1f 100644
--- a/test/expect-tests/dune_rpc_impl/dune_rpc_impl_tests.ml
+++ b/test/expect-tests/dune_rpc_impl/dune_rpc_impl_tests.ml
@@ -51,28 +51,32 @@ let%expect_test "serialize and deserialize error message" =
     Error: Oh no!
     ---- Original ----
     Vbox
-      0,
-      Seq
-        Box
-          0,
-          Concat
-            Break ("", 1, ""), ("", 0, ""),
-            [ Seq Tag Error, Verbatim "Error", Char :; Verbatim "Oh no!" ],
-        Break ("", 0, ""), ("", 0, "")
+      (0,
+       Seq
+         (Box
+            (0,
+             Concat
+               (Break (("", 1, ""), ("", 0, "")),
+                [ Seq (Tag (Error, Verbatim "Error"), Char :)
+                ; Verbatim "Oh no!"
+                ])),
+          Break (("", 0, ""), ("", 0, ""))))
     ------- RPC ------
     Vbox
-      0,
-      Seq
-        Box
-          0,
-          Vbox
-            0,
-            Box
-              0,
-              Concat
-                Break ("", 1, ""), ("", 0, ""),
-                [ Seq Tag Error, Verbatim "Error", Char :; Verbatim "Oh no!" ],
-        Break ("", 0, ""), ("", 0, "") |}]
+      (0,
+       Seq
+         (Box
+            (0,
+             Vbox
+               (0,
+                Box
+                  (0,
+                   Concat
+                     (Break (("", 1, ""), ("", 0, "")),
+                      [ Seq (Tag (Error, Verbatim "Error"), Char :)
+                      ; Verbatim "Oh no!"
+                      ])))),
+          Break (("", 0, ""), ("", 0, "")))) |}]
 ;;
 
 let%expect_test "serialize and deserialize error message with location" =
@@ -91,44 +95,45 @@ let%expect_test "serialize and deserialize error message with location" =
     Error: An error with location!
     ---- Original ----
     Vbox
-      0,
-      Concat
-        Nop,
-        [ Seq
-            Box 0, Tag Loc, Text "File \"Bar\", line 1, characters 2-3:",
-            Break ("", 0, ""), ("", 0, "")
-        ; Seq
-            Box
-              0,
-              Concat
-                Break ("", 1, ""), ("", 0, ""),
-                [ Seq Tag Error, Verbatim "Error", Char :
-                ; Verbatim "An error with location!"
-                ],
-            Break ("", 0, ""), ("", 0, "")
-        ]
+      (0,
+       Concat
+         (Nop,
+          [ Seq
+              (Box (0, Tag (Loc, Text "File \"Bar\", line 1, characters 2-3:")),
+               Break (("", 0, ""), ("", 0, "")))
+          ; Seq
+              (Box
+                 (0,
+                  Concat
+                    (Break (("", 1, ""), ("", 0, "")),
+                     [ Seq (Tag (Error, Verbatim "Error"), Char :)
+                     ; Verbatim "An error with location!"
+                     ])),
+               Break (("", 0, ""), ("", 0, "")))
+          ]))
     ------- RPC ------
     Vbox
-      0,
-      Concat
-        Nop,
-        [ Seq
-            Box 0, Tag Loc, Text "File \"/Foo/Bar\", line 1, characters 2-3:",
-            Break ("", 0, ""), ("", 0, "")
-        ; Seq
-            Box
-              0,
-              Vbox
-                0,
-                Box
-                  0,
-                  Concat
-                    Break ("", 1, ""), ("", 0, ""),
-                    [ Seq Tag Error, Verbatim "Error", Char :
-                    ; Verbatim "An error with location!"
-                    ],
-            Break ("", 0, ""), ("", 0, "")
-        ] |}]
+      (0,
+       Concat
+         (Nop,
+          [ Seq
+              (Box
+                 (0, Tag (Loc, Text "File \"/Foo/Bar\", line 1, characters 2-3:")),
+               Break (("", 0, ""), ("", 0, "")))
+          ; Seq
+              (Box
+                 (0,
+                  Vbox
+                    (0,
+                     Box
+                       (0,
+                        Concat
+                          (Break (("", 1, ""), ("", 0, "")),
+                           [ Seq (Tag (Error, Verbatim "Error"), Char :)
+                           ; Verbatim "An error with location!"
+                           ])))),
+               Break (("", 0, ""), ("", 0, "")))
+          ])) |}]
 ;;
 
 let%expect_test "serialize and deserialize error with location excerpt and hint" =
@@ -158,78 +163,83 @@ let%expect_test "serialize and deserialize error with location excerpt and hint"
     Hint: Hint 2
     ---- Original ----
     Vbox
-      0,
-      Concat
-        Nop,
-        [ Seq
-            Box 0, Tag Loc, Text "File \"foo.ml\", line 1, characters 2-3:",
-            Break ("", 0, ""), ("", 0, "")
-        ; Seq
-            Box
-              0,
-              Concat
-                Break ("", 1, ""), ("", 0, ""),
-                [ Seq Tag Error, Verbatim "Error", Char :
-                ; Verbatim "An error with location!"
-                ],
-            Break ("", 0, ""), ("", 0, "")
-        ; Seq
-            Box
-              0,
-              Seq
-                Seq Tag Hint, Verbatim "Hint:", Break ("", 1, ""), ("", 0, ""),
-                Verbatim "Hint 1",
-            Break ("", 0, ""), ("", 0, "")
-        ; Seq
-            Box
-              0,
-              Seq
-                Seq Tag Hint, Verbatim "Hint:", Break ("", 1, ""), ("", 0, ""),
-                Verbatim "Hint 2",
-            Break ("", 0, ""), ("", 0, "")
-        ]
+      (0,
+       Concat
+         (Nop,
+          [ Seq
+              (Box
+                 (0, Tag (Loc, Text "File \"foo.ml\", line 1, characters 2-3:")),
+               Break (("", 0, ""), ("", 0, "")))
+          ; Seq
+              (Box
+                 (0,
+                  Concat
+                    (Break (("", 1, ""), ("", 0, "")),
+                     [ Seq (Tag (Error, Verbatim "Error"), Char :)
+                     ; Verbatim "An error with location!"
+                     ])),
+               Break (("", 0, ""), ("", 0, "")))
+          ; Seq
+              (Box
+                 (0,
+                  Seq
+                    (Seq
+                       (Tag (Hint, Verbatim "Hint:"),
+                        Break (("", 1, ""), ("", 0, ""))),
+                     Verbatim "Hint 1")),
+               Break (("", 0, ""), ("", 0, "")))
+          ; Seq
+              (Box
+                 (0,
+                  Seq
+                    (Seq
+                       (Tag (Hint, Verbatim "Hint:"),
+                        Break (("", 1, ""), ("", 0, ""))),
+                     Verbatim "Hint 2")),
+               Break (("", 0, ""), ("", 0, "")))
+          ]))
     ------- RPC ------
     Vbox
-      0,
-      Concat
-        Nop,
-        [ Seq
-            Box
-              0,
-              Tag
-                Loc,
-                Text
-                  "File \"TEST/foo.ml\", line 1, characters 2-3:",
-            Break ("", 0, ""), ("", 0, "")
-        ; Seq
-            Box
-              0,
-              Vbox
-                0,
-                Concat
-                  Break ("", 0, ""), ("", 0, ""),
-                  [ Box
-                      0,
-                      Concat
-                        Break ("", 1, ""), ("", 0, ""),
-                        [ Seq Tag Error, Verbatim "Error", Char :
-                        ; Verbatim "An error with location!"
-                        ]
-                  ; Box
-                      0,
-                      Seq
-                        Seq
-                          Tag Hint, Verbatim "Hint:",
-                          Break ("", 1, ""), ("", 0, ""),
-                        Verbatim "Hint 1"
-                  ; Box
-                      0,
-                      Seq
-                        Seq
-                          Tag Hint, Verbatim "Hint:",
-                          Break ("", 1, ""), ("", 0, ""),
-                        Verbatim "Hint 2"
-                  ],
-            Break ("", 0, ""), ("", 0, "")
-        ] |}]
+      (0,
+       Concat
+         (Nop,
+          [ Seq
+              (Box
+                 (0,
+                  Tag
+                    (Loc,
+                     Text
+                       "File \"TEST/foo.ml\", line 1, characters 2-3:")),
+               Break (("", 0, ""), ("", 0, "")))
+          ; Seq
+              (Box
+                 (0,
+                  Vbox
+                    (0,
+                     Concat
+                       (Break (("", 0, ""), ("", 0, "")),
+                        [ Box
+                            (0,
+                             Concat
+                               (Break (("", 1, ""), ("", 0, "")),
+                                [ Seq (Tag (Error, Verbatim "Error"), Char :)
+                                ; Verbatim "An error with location!"
+                                ]))
+                        ; Box
+                            (0,
+                             Seq
+                               (Seq
+                                  (Tag (Hint, Verbatim "Hint:"),
+                                   Break (("", 1, ""), ("", 0, ""))),
+                                Verbatim "Hint 1"))
+                        ; Box
+                            (0,
+                             Seq
+                               (Seq
+                                  (Tag (Hint, Verbatim "Hint:"),
+                                   Break (("", 1, ""), ("", 0, ""))),
+                                Verbatim "Hint 2"))
+                        ]))),
+               Break (("", 0, ""), ("", 0, "")))
+          ])) |}]
 ;;
diff --git a/test/expect-tests/memo/main.ml b/test/expect-tests/memo/main.ml
index 8bc927a7461..6c4776a7242 100644
--- a/test/expect-tests/memo/main.ml
+++ b/test/expect-tests/memo/main.ml
@@ -308,7 +308,7 @@ let%expect_test _ =
   [%expect
     {|
       (Some [ (Some "lazy_memo", "foo"); (Some "id", "lazy: foo") ],
-      Some [ (Some "lazy_memo", "foo"); (Some "id", "lazy: foo") ])
+       Some [ (Some "lazy_memo", "foo"); (Some "id", "lazy: foo") ])
     |}]
 ;;
 
@@ -331,7 +331,7 @@ let%expect_test _ =
   [%expect
     {|
     (Some [ (Some "lazy_memo", "foo"); (None, ()) ],
-    Some [ (Some "lazy_memo", "foo"); (None, ()) ])
+     Some [ (Some "lazy_memo", "foo"); (None, ()) ])
   |}]
 ;;
 
diff --git a/test/expect-tests/module_tests.ml b/test/expect-tests/module_tests.ml
index e412a90772e..8da1d6a9b89 100644
--- a/test/expect-tests/module_tests.ml
+++ b/test/expect-tests/module_tests.ml
@@ -23,9 +23,9 @@ let%expect_test "Module.Kind encoding round trip" =
   test Impl;
   [%expect {| { ast = "impl"; decoded = Ok Impl } |}];
   test (Alias []);
-  [%expect {| { ast = "alias"; decoded = Ok Alias [] } |}];
+  [%expect {| { ast = "alias"; decoded = Ok (Alias []) } |}];
   test (Alias [ module_name "A" ]);
-  [%expect {| { ast = "(alias (A))"; decoded = Ok Alias [ "A" ] } |}];
+  [%expect {| { ast = "(alias (A))"; decoded = Ok (Alias [ "A" ]) } |}];
   test (Alias [ module_name "A"; module_name "B" ]);
-  [%expect {| { ast = "(alias (A B))"; decoded = Ok Alias [ "A"; "B" ] } |}]
+  [%expect {| { ast = "(alias (A B))"; decoded = Ok (Alias [ "A"; "B" ]) } |}]
 ;;