From 6cee83187cada629d399077a9795d4e32b5c82b6 Mon Sep 17 00:00:00 2001
From: Gabriel Nordeborn <gabbe.nord@gmail.com>
Date: Mon, 29 Jan 2024 20:50:22 +0100
Subject: [PATCH 1/5] dict as a builtin type

---
 jscomp/ml/ast_untagged_variants.ml |  1 +
 jscomp/ml/predef.ml                | 14 +++++++++++---
 jscomp/ml/predef.mli               |  2 ++
 jscomp/others/js_dict.res          |  6 +++---
 jscomp/others/js_dict.resi         |  6 +++---
 jscomp/test/js_dict_test.res       |  2 +-
 lib/es6/js_dict.js                 |  3 ++-
 lib/es6/js_json.js                 |  3 +--
 lib/js/js_dict.js                  |  3 ++-
 lib/js/js_json.js                  |  3 +--
 10 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/jscomp/ml/ast_untagged_variants.ml b/jscomp/ml/ast_untagged_variants.ml
index 1f721eba45..440299cb32 100644
--- a/jscomp/ml/ast_untagged_variants.ml
+++ b/jscomp/ml/ast_untagged_variants.ml
@@ -142,6 +142,7 @@ let reportConstructorMoreThanOneArg ~loc ~name =
 
 let type_is_builtin_object (t : Types.type_expr) =
   match t.desc with
+  | Tconstr (Path.Pident ident, [_], _) when Ident.name ident = "dict" -> true
   | Tconstr (path, _, _) ->
     let name = Path.name path in
     name = "Js.Dict.t" || name = "Js_dict.t"
diff --git a/jscomp/ml/predef.ml b/jscomp/ml/predef.ml
index fe5749d7dc..a33e37334d 100644
--- a/jscomp/ml/predef.ml
+++ b/jscomp/ml/predef.ml
@@ -40,6 +40,7 @@ and ident_array = ident_create "array"
 and ident_list = ident_create "list"
 and ident_option = ident_create "option"
 and ident_result = ident_create "result"
+and ident_dict = ident_create "dict"
 
 and ident_int64 = ident_create "int64"
 and ident_lazy_t = ident_create "lazy_t"
@@ -82,8 +83,7 @@ and path_array = Pident ident_array
 and path_list = Pident ident_list
 and path_option = Pident ident_option
 and path_result = Pident ident_result
-
-
+and path_dict = Pident ident_dict
 and path_int64 = Pident ident_int64
 and path_lazy_t = Pident ident_lazy_t
 and path_string = Pident ident_string
@@ -105,6 +105,7 @@ and type_array t = newgenty (Tconstr(path_array, [t], ref Mnil))
 and type_list t = newgenty (Tconstr(path_list, [t], ref Mnil))
 and type_option t = newgenty (Tconstr(path_option, [t], ref Mnil))
 and type_result t1 t2 = newgenty (Tconstr(path_result, [t1; t2], ref Mnil))
+and type_dict t = newgenty (Tconstr(path_option, [t], ref Mnil))
 
 and type_int64 = newgenty (Tconstr(path_int64, [], ref Mnil))
 and type_lazy_t t = newgenty (Tconstr(path_lazy_t, [t], ref Mnil))
@@ -226,6 +227,12 @@ let common_initial_env add_type add_extension empty_env =
      Type_variant([cstr ident_ok [tvar1];
                    cstr ident_error [tvar2]]);
      type_variance = [Variance.covariant; Variance.covariant]}
+  and decl_dict =
+    let tvar = newgenvar() in
+    {decl_abstr with
+      type_params = [tvar];
+      type_arity = 1;
+      type_variance = [Variance.covariant]}
   and decl_uncurried =
     let tvar1, tvar2 = newgenvar(), newgenvar() in
     {decl_abstr with
@@ -292,6 +299,7 @@ let common_initial_env add_type add_extension empty_env =
   add_type ident_lazy_t decl_lazy_t (
   add_type ident_option decl_option (
   add_type ident_result decl_result (
+  add_type ident_dict decl_dict (
   add_type ident_list decl_list (
   add_type ident_array decl_array (
   add_type ident_exn decl_exn (
@@ -305,7 +313,7 @@ let common_initial_env add_type add_extension empty_env =
   add_type ident_extension_constructor decl_abstr (
   add_type ident_floatarray decl_abstr (
     add_type ident_promise decl_promise (
-      empty_env))))))))))))))))))))))))))
+      empty_env)))))))))))))))))))))))))))
 
 let build_initial_env add_type add_exception empty_env =
   let common = common_initial_env add_type add_exception empty_env in
diff --git a/jscomp/ml/predef.mli b/jscomp/ml/predef.mli
index a998aa6807..a3f15f9071 100644
--- a/jscomp/ml/predef.mli
+++ b/jscomp/ml/predef.mli
@@ -29,6 +29,7 @@ val type_array: type_expr -> type_expr
 val type_list: type_expr -> type_expr
 val type_option: type_expr -> type_expr
 val type_result: type_expr -> type_expr -> type_expr
+val type_dict: type_expr -> type_expr
 
 val type_int64: type_expr
 val type_lazy_t: type_expr -> type_expr
@@ -47,6 +48,7 @@ val path_array: Path.t
 val path_list: Path.t
 val path_option: Path.t
 val path_result: Path.t
+val path_dict: Path.t
 
 val path_int64: Path.t
 val path_lazy_t: Path.t
diff --git a/jscomp/others/js_dict.res b/jscomp/others/js_dict.res
index b08e0759b2..52335a5675 100644
--- a/jscomp/others/js_dict.res
+++ b/jscomp/others/js_dict.res
@@ -25,7 +25,7 @@
 /*** Provides a simple key-value dictionary abstraction over native JavaScript objects */
 
 /** The dict type */
-type t<'a>
+type t<'a> = dict<'a>
 
 /** The key type, an alias of string */
 type key = string
@@ -60,7 +60,7 @@ external keys: t<'a> => array<key> = "Object.keys"
 @obj
 external empty: unit => t<'a> = ""
 
-let unsafeDeleteKey: (. t<string>, string) => unit = %raw(` function (dict,key){
+let unsafeDeleteKey: (t<string>, string) => unit = %raw(` function (dict,key){
       delete dict[key];
      }
   `)
@@ -118,7 +118,7 @@ let map = (f, source) => {
   let l = Js_array2.length(keys)
   for i in 0 to l - 1 {
     let key = Js_array2.unsafe_get(keys, i)
-    set(target, key, f(. unsafeGet(source, key)))
+    set(target, key, f(unsafeGet(source, key)))
   }
   target
 }
diff --git a/jscomp/others/js_dict.resi b/jscomp/others/js_dict.resi
index c9c4584f44..8baa9407d0 100644
--- a/jscomp/others/js_dict.resi
+++ b/jscomp/others/js_dict.resi
@@ -39,7 +39,7 @@ Dictionary type (ie an '{ }' JS object). However it is restricted to hold a
 single type; therefore values must have the same type. This Dictionary type is
 mostly used with the Js_json.t type.
 */
-type t<'a>
+type t<'a> = dict<'a>
 
 /**
   The type for dictionary keys. This means that dictionaries *must* use `string`s as their keys.
@@ -107,7 +107,7 @@ external keys: t<'a> => array<string> = "Object.keys"
 external empty: unit => t<'a> = ""
 
 /** Experimental internal function */
-let unsafeDeleteKey: (. t<string>, string) => unit
+let unsafeDeleteKey: (t<string>, string) => unit
 
 /**
 Returns an array of key/value pairs in the given dictionary (ES2017).
@@ -170,4 +170,4 @@ let salePrices = Js.Dict.map(discount, prices)
 salePrices == Js.Dict.fromList(list{("pen", 0.90), ("book", 4.50), ("stapler", 6.30)})
 ```
 */
-let map: ((. 'a) => 'b, t<'a>) => t<'b>
+let map: ('a => 'b, t<'a>) => t<'b>
diff --git a/jscomp/test/js_dict_test.res b/jscomp/test/js_dict_test.res
index 8db793714c..9ae9f08bd2 100644
--- a/jscomp/test/js_dict_test.res
+++ b/jscomp/test/js_dict_test.res
@@ -26,7 +26,7 @@ let suites = {
     ("fromArray", _ => Eq([("x", 23), ("y", 46)], fromArray([("x", 23), ("y", 46)]) |> entries)),
     (
       "map",
-      _ => Eq({"foo": "43", "bar": "86"} |> Obj.magic, map((. i) => string_of_int(i), obj())),
+      _ => Eq({"foo": "43", "bar": "86"} |> Obj.magic, map(i => string_of_int(i), obj())),
     ),
   }
 }
diff --git a/lib/es6/js_dict.js b/lib/es6/js_dict.js
index 2be98231e8..4a99ee0479 100644
--- a/lib/es6/js_dict.js
+++ b/lib/es6/js_dict.js
@@ -1,5 +1,6 @@
 
 
+import * as Curry from "./curry.js";
 import * as Caml_option from "./caml_option.js";
 
 function get(dict, k) {
@@ -68,7 +69,7 @@ function map(f, source) {
   var l = keys.length;
   for(var i = 0; i < l; ++i){
     var key = keys[i];
-    target[key] = f(source[key]);
+    target[key] = Curry._1(f, source[key]);
   }
   return target;
 }
diff --git a/lib/es6/js_json.js b/lib/es6/js_json.js
index 961ee2e9ab..61c6fbcd33 100644
--- a/lib/es6/js_json.js
+++ b/lib/es6/js_json.js
@@ -1,6 +1,5 @@
 
 
-import * as Caml_option from "./caml_option.js";
 
 var Kind = {};
 
@@ -75,7 +74,7 @@ function decodeNumber(json) {
 
 function decodeObject(json) {
   if (typeof json === "object" && !Array.isArray(json) && json !== null) {
-    return Caml_option.some(json);
+    return json;
   }
   
 }
diff --git a/lib/js/js_dict.js b/lib/js/js_dict.js
index 4dfafed9ff..beadd32063 100644
--- a/lib/js/js_dict.js
+++ b/lib/js/js_dict.js
@@ -1,5 +1,6 @@
 'use strict';
 
+var Curry = require("./curry.js");
 var Caml_option = require("./caml_option.js");
 
 function get(dict, k) {
@@ -68,7 +69,7 @@ function map(f, source) {
   var l = keys.length;
   for(var i = 0; i < l; ++i){
     var key = keys[i];
-    target[key] = f(source[key]);
+    target[key] = Curry._1(f, source[key]);
   }
   return target;
 }
diff --git a/lib/js/js_json.js b/lib/js/js_json.js
index 6128ff3e74..8d9166a172 100644
--- a/lib/js/js_json.js
+++ b/lib/js/js_json.js
@@ -1,6 +1,5 @@
 'use strict';
 
-var Caml_option = require("./caml_option.js");
 
 var Kind = {};
 
@@ -75,7 +74,7 @@ function decodeNumber(json) {
 
 function decodeObject(json) {
   if (typeof json === "object" && !Array.isArray(json) && json !== null) {
-    return Caml_option.some(json);
+    return json;
   }
   
 }

From 6e49b4dc7fe4d811e784380a4a2ce562f0a84cc2 Mon Sep 17 00:00:00 2001
From: Gabriel Nordeborn <gabbe.nord@gmail.com>
Date: Mon, 29 Jan 2024 20:53:55 +0100
Subject: [PATCH 2/5] fix

---
 jscomp/ml/predef.ml | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/jscomp/ml/predef.ml b/jscomp/ml/predef.ml
index a33e37334d..a65174625e 100644
--- a/jscomp/ml/predef.ml
+++ b/jscomp/ml/predef.ml
@@ -84,6 +84,8 @@ and path_list = Pident ident_list
 and path_option = Pident ident_option
 and path_result = Pident ident_result
 and path_dict = Pident ident_dict
+
+
 and path_int64 = Pident ident_int64
 and path_lazy_t = Pident ident_lazy_t
 and path_string = Pident ident_string
@@ -105,7 +107,7 @@ and type_array t = newgenty (Tconstr(path_array, [t], ref Mnil))
 and type_list t = newgenty (Tconstr(path_list, [t], ref Mnil))
 and type_option t = newgenty (Tconstr(path_option, [t], ref Mnil))
 and type_result t1 t2 = newgenty (Tconstr(path_result, [t1; t2], ref Mnil))
-and type_dict t = newgenty (Tconstr(path_option, [t], ref Mnil))
+and type_dict t = newgenty (Tconstr(path_dict, [t], ref Mnil))
 
 and type_int64 = newgenty (Tconstr(path_int64, [], ref Mnil))
 and type_lazy_t t = newgenty (Tconstr(path_lazy_t, [t], ref Mnil))

From 42e24613fe63f073c5ab98f7cfdda6596443c7b8 Mon Sep 17 00:00:00 2001
From: Gabriel Nordeborn <gabbe.nord@gmail.com>
Date: Mon, 29 Jan 2024 20:56:44 +0100
Subject: [PATCH 3/5] revert unintended changes

---
 jscomp/others/js_dict.res    | 4 ++--
 jscomp/others/js_dict.resi   | 4 ++--
 jscomp/test/js_dict_test.res | 2 +-
 lib/es6/js_dict.js           | 3 +--
 lib/js/js_dict.js            | 3 +--
 5 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/jscomp/others/js_dict.res b/jscomp/others/js_dict.res
index 52335a5675..5daef592fd 100644
--- a/jscomp/others/js_dict.res
+++ b/jscomp/others/js_dict.res
@@ -60,7 +60,7 @@ external keys: t<'a> => array<key> = "Object.keys"
 @obj
 external empty: unit => t<'a> = ""
 
-let unsafeDeleteKey: (t<string>, string) => unit = %raw(` function (dict,key){
+let unsafeDeleteKey: (. t<string>, string) => unit = %raw(` function (dict,key){
       delete dict[key];
      }
   `)
@@ -118,7 +118,7 @@ let map = (f, source) => {
   let l = Js_array2.length(keys)
   for i in 0 to l - 1 {
     let key = Js_array2.unsafe_get(keys, i)
-    set(target, key, f(unsafeGet(source, key)))
+    set(target, key, f(. unsafeGet(source, key)))
   }
   target
 }
diff --git a/jscomp/others/js_dict.resi b/jscomp/others/js_dict.resi
index 8baa9407d0..5f6a30ffd4 100644
--- a/jscomp/others/js_dict.resi
+++ b/jscomp/others/js_dict.resi
@@ -107,7 +107,7 @@ external keys: t<'a> => array<string> = "Object.keys"
 external empty: unit => t<'a> = ""
 
 /** Experimental internal function */
-let unsafeDeleteKey: (t<string>, string) => unit
+let unsafeDeleteKey: (. t<string>, string) => unit
 
 /**
 Returns an array of key/value pairs in the given dictionary (ES2017).
@@ -170,4 +170,4 @@ let salePrices = Js.Dict.map(discount, prices)
 salePrices == Js.Dict.fromList(list{("pen", 0.90), ("book", 4.50), ("stapler", 6.30)})
 ```
 */
-let map: ('a => 'b, t<'a>) => t<'b>
+let map: ((. 'a) => 'b, t<'a>) => t<'b>
diff --git a/jscomp/test/js_dict_test.res b/jscomp/test/js_dict_test.res
index 9ae9f08bd2..8db793714c 100644
--- a/jscomp/test/js_dict_test.res
+++ b/jscomp/test/js_dict_test.res
@@ -26,7 +26,7 @@ let suites = {
     ("fromArray", _ => Eq([("x", 23), ("y", 46)], fromArray([("x", 23), ("y", 46)]) |> entries)),
     (
       "map",
-      _ => Eq({"foo": "43", "bar": "86"} |> Obj.magic, map(i => string_of_int(i), obj())),
+      _ => Eq({"foo": "43", "bar": "86"} |> Obj.magic, map((. i) => string_of_int(i), obj())),
     ),
   }
 }
diff --git a/lib/es6/js_dict.js b/lib/es6/js_dict.js
index 4a99ee0479..2be98231e8 100644
--- a/lib/es6/js_dict.js
+++ b/lib/es6/js_dict.js
@@ -1,6 +1,5 @@
 
 
-import * as Curry from "./curry.js";
 import * as Caml_option from "./caml_option.js";
 
 function get(dict, k) {
@@ -69,7 +68,7 @@ function map(f, source) {
   var l = keys.length;
   for(var i = 0; i < l; ++i){
     var key = keys[i];
-    target[key] = Curry._1(f, source[key]);
+    target[key] = f(source[key]);
   }
   return target;
 }
diff --git a/lib/js/js_dict.js b/lib/js/js_dict.js
index beadd32063..4dfafed9ff 100644
--- a/lib/js/js_dict.js
+++ b/lib/js/js_dict.js
@@ -1,6 +1,5 @@
 'use strict';
 
-var Curry = require("./curry.js");
 var Caml_option = require("./caml_option.js");
 
 function get(dict, k) {
@@ -69,7 +68,7 @@ function map(f, source) {
   var l = keys.length;
   for(var i = 0; i < l; ++i){
     var key = keys[i];
-    target[key] = Curry._1(f, source[key]);
+    target[key] = f(source[key]);
   }
   return target;
 }

From 9952724eae1f4e53ac6689957020d7e17e29d901 Mon Sep 17 00:00:00 2001
From: Gabriel Nordeborn <gabbe.nord@gmail.com>
Date: Tue, 30 Jan 2024 09:39:34 +0100
Subject: [PATCH 4/5] adapt gentype to dict as built in

---
 jscomp/gentype/TranslateTypeExprFromTypes.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/jscomp/gentype/TranslateTypeExprFromTypes.ml b/jscomp/gentype/TranslateTypeExprFromTypes.ml
index 45cde1fe24..a57468dba4 100644
--- a/jscomp/gentype/TranslateTypeExprFromTypes.ml
+++ b/jscomp/gentype/TranslateTypeExprFromTypes.ml
@@ -236,7 +236,7 @@ let translateConstr ~config ~paramsTranslation ~(path : Path.t) ~typeEnv =
   | ( (["Js"; "Promise"; "t"] | ["Promise"; "t"] | ["promise"]),
       [paramTranslation] ) ->
     {paramTranslation with type_ = Promise paramTranslation.type_}
-  | (["Js"; "Dict"; "t"] | ["Dict"; "t"]), [paramTranslation] ->
+  | (["Js"; "Dict"; "t"] | ["Dict"; "t"] | ["dict"]), [paramTranslation] ->
     {paramTranslation with type_ = Dict paramTranslation.type_}
   | ["function$"], [arg; _arity] ->
     {dependencies = arg.dependencies; type_ = arg.type_}

From fba5e8a9dd49df0f76a14c89ce6f8f59e378aa33 Mon Sep 17 00:00:00 2001
From: Gabriel Nordeborn <gabbe.nord@gmail.com>
Date: Tue, 30 Jan 2024 10:08:08 +0100
Subject: [PATCH 5/5] changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 81557b99d3..e400636cbf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@
 
 - Experimental support of tagged template literals, eg ```sql`select * from ${table}```. https://github.com/rescript-lang/rescript-compiler/pull/6250
 - Experimental support for generic/custom JSX transforms. https://github.com/rescript-lang/rescript-compiler/pull/6565
+- `dict` is now a builtin type. https://github.com/rescript-lang/rescript-compiler/pull/6590
 
 #### :bug: Bug Fix