Make components actually uncurried functions in uncurried mode.

CHANGELOG.md

@@ -26,8 +26,9 @@ subset of the arguments, and return a curried type with the remaining ones https
 - Support optional named arguments without a final unit in uncurried functions https://github.com/rescript-lang/rescript-compiler/pull/5907
 - Add support for uncurried mode: a mode where everything is considered uncurried, whether with or without the `.`. This can be turned on with `@@uncurried` locally in a file. For project-level configuration in `bsconfig.json`, there's a boolean config `"uncurried"`, which propagates to dependencies, to turn on uncurried mode.
 Since there's no syntax for partial application in this new mode, introduce `@res.partial foo(x)` to express partial application. This is temporary and will later have some surface syntax.
+Make uncurried functions a subtype of curried functions, and allow application for uncurried functions.
 Use best effort to determine the config when formatting a file.
-https://github.com/rescript-lang/rescript-compiler/pull/5968 https://github.com/rescript-lang/rescript-compiler/pull/6080
+https://github.com/rescript-lang/rescript-compiler/pull/5968 https://github.com/rescript-lang/rescript-compiler/pull/6080 https://github.com/rescript-lang/rescript-compiler/pull/6086
 
 #### :boom: Breaking Change
 

jscomp/ml/ctype.ml

@@ -2341,9 +2341,6 @@ let rec unify (env:Env.t ref) t1 t2 =
         with Cannot_expand ->
           unify2 env t1 t2
         end
-    | (Tconstr (Pident {name="function$"}, [tFun; _], _), Tarrow _) when !Config.uncurried = Uncurried ->
-        (* subtype: an uncurried function is cast to a curried one *)
-        unify2 env tFun t2
     | _ ->
         unify2 env t1 t2
     end;
@@ -2399,6 +2396,9 @@ and unify3 env t1 t1' t2 t2' =
       link_type t2' t1;
   | (Tfield _, Tfield _) -> (* special case for GADTs *)
       unify_fields env t1' t2'
+  | (Tconstr (Pident {name="function$"}, [tFun; _], _), Tarrow _) when !Config.uncurried = Uncurried ->
+      (* subtype: an uncurried function is cast to a curried one *)
+      unify2 env tFun t2
   | _ ->
     begin match !umode with
     | Expression ->

jscomp/stdlib-406/pervasivesU.res

@@ -15,6 +15,25 @@
 
 @@uncurried
 
+module Jsx = {
+  type element
+  type ref
+
+  @val external null: element = "null"
+
+  external float: float => element = "%identity"
+  external int: int => element = "%identity"
+  external string: string => element = "%identity"
+
+  external array: array<element> => element = "%identity"
+
+  type componentLike<'props, 'return> = 'props => 'return
+  type component<'props> = componentLike<'props, element>
+
+  /* this function exists to prepare for making `component` abstract */
+  external component: componentLike<'props, element> => component<'props> = "%identity"
+}
+
 /* Internal */
 external __unsafe_cast: 'a => 'b = "%identity"
 
@@ -301,12 +320,10 @@ let exit_function = ref(ignore)
 let at_exit = f => {
   let g = exit_function.contents
   exit_function :=
-    (
-      () => {
-        f()
-        g()
-      }
-    )
+    () => {
+      f()
+      g()
+    }
 }
 
 let do_at_exit = () => exit_function.contents()

jscomp/stdlib-406/pervasivesU.resi

@@ -1,4 +1,4 @@
-@@ocaml.text(/* ************************************************************************ */
+/* ************************************************************************ */
 /*  */
 /* OCaml */
 /*  */
@@ -13,9 +13,7 @@
 /*  */
 /* ************************************************************************ */
 
-@@uncurried
-
-" The initially opened module.
+/*** The initially opened module.
 
    This module provides the basic operations over the built-in types
    (numbers, booleans, byte sequences, strings, exceptions, references,
@@ -24,7 +22,28 @@
    This module is automatically opened at the beginning of each compilation.
    All components of this module can therefore be referred by their short
    name, without prefixing them by [Pervasives].
-")
+*/
+
+@@uncurried
+
+module Jsx: {
+  type element
+  type ref
+
+  @val external null: element = "null"
+
+  external float: float => element = "%identity"
+  external int: int => element = "%identity"
+  external string: string => element = "%identity"
+
+  external array: array<element> => element = "%identity"
+
+  type componentLike<'props, 'return> = 'props => 'return
+  type component<'props> = componentLike<'props, element>
+
+  /* this function exists to prepare for making `component` abstract */
+  external component: componentLike<'props, element> => component<'props> = "%identity"
+}
 
 /* Internal */
 external __unsafe_cast: 'a => 'b = "%identity"

jscomp/test/UncurriedAlways.js

@@ -43,6 +43,10 @@ function bar3(__x) {
   return foo3(__x, 3, 4);
 }
 
+function q(param) {
+  return null;
+}
+
 exports.foo = foo;
 exports.z = z;
 exports.bar = bar;
@@ -54,4 +58,5 @@ exports.foo2 = foo2;
 exports.bar2 = bar2;
 exports.foo3 = foo3;
 exports.bar3 = bar3;
+exports.q = q;
 /*  Not a pure module */

jscomp/test/UncurriedAlways.res

@@ -14,12 +14,15 @@ let a = 3->foo(. 4)
 
 Js.log(a) // Test automatic uncurried application
 
-let _ = Js.Array2.map([1], (. x) => x+1)
+let _ = Js.Array2.map([1], (. x) => x + 1)
 
 let ptl = @res.partial foo(10) // force partial application
 
-let foo2 = (x,y) => x+y
+let foo2 = (x, y) => x + y
 let bar2: _ => _ = foo2(_, 3)
 
-let foo3 = (x,y,z) => x+y+z
-let bar3 : _ => _ = foo3(_, 3, 4)
+let foo3 = (x, y, z) => x + y + z
+let bar3: _ => _ = foo3(_, 3, 4)
+
+type cmp = Jsx.component<int>
+let q: cmp = _ => Jsx.null // Check that subtyping works past type definitions

lib/es6/pervasivesU.js

@@ -6,6 +6,8 @@ import * as Caml_string from "./caml_string.js";
 import * as Caml_exceptions from "./caml_exceptions.js";
 import * as Caml_js_exceptions from "./caml_js_exceptions.js";
 
+var Jsx = {};
+
 function failwith(s) {
   throw {
         RE_EXN_ID: "Failure",
@@ -216,6 +218,7 @@ var min_float = 2.22507385850720138e-308;
 var epsilon_float = 2.22044604925031308e-16;
 
 export {
+  Jsx ,
   invalid_arg ,
   failwith ,
   Exit ,

lib/js/pervasivesU.js

@@ -6,6 +6,8 @@ var Caml_string = require("./caml_string.js");
 var Caml_exceptions = require("./caml_exceptions.js");
 var Caml_js_exceptions = require("./caml_js_exceptions.js");
 
+var Jsx = {};
+
 function failwith(s) {
   throw {
         RE_EXN_ID: "Failure",
@@ -215,6 +217,7 @@ var min_float = 2.22507385850720138e-308;
 
 var epsilon_float = 2.22044604925031308e-16;
 
+exports.Jsx = Jsx;
 exports.invalid_arg = invalid_arg;
 exports.failwith = failwith;
 exports.Exit = Exit;

res_syntax/src/reactjs_jsx_v3.ml

@@ -959,6 +959,13 @@ let jsxMapper ~config =
               }
               innerExpressionWithRef
           in
+          let fullExpression =
+            if !Config.uncurried = Uncurried then
+              fullExpression
+              |> Ast_uncurried.uncurriedFun ~loc:fullExpression.pexp_loc
+                   ~arity:1
+            else fullExpression
+          in
           let fullExpression =
             match fullModuleName with
             | "" -> fullExpression

res_syntax/src/reactjs_jsx_v4.ml

@@ -952,6 +952,12 @@ let mapBinding ~config ~emptyLoc ~pstr_loc ~fileName ~recFlag binding =
            innerExpression
         else innerExpression)
     in
+    let fullExpression =
+      if !Config.uncurried = Uncurried then
+        fullExpression
+        |> Ast_uncurried.uncurriedFun ~loc:fullExpression.pexp_loc ~arity:1
+      else fullExpression
+    in
     let fullExpression =
       match fullModuleName with
       | "" -> fullExpression