Spring cleaning: remove uncurried arity 0. (rescript-lang#6118)

Uncurried arity 0 does not exist in .res.
It was only used in certain internal .ml files.

Author: cristianoc

jscomp/frontend/ast_core_type.ml

@@ -115,18 +115,12 @@ let rec get_uncurry_arity_aux (ty : t) acc =
   | _ -> acc
 
 (**
-   {[ unit -> 'b ]} return arity 0
+   {[ unit -> 'b ]} return arity 1
    {[ unit -> 'a1 -> a2']} arity 2
    {[ 'a1 -> 'a2 -> ... 'aN -> 'b ]} return arity N
 *)
 let get_uncurry_arity (ty : t) =
   match ty.ptyp_desc with
-  | Ptyp_arrow
-      (Nolabel, { ptyp_desc = Ptyp_constr ({ txt = Lident "unit" }, []) }, rest)
-    -> (
-      match rest with
-      | { ptyp_desc = Ptyp_arrow _ } -> Some (get_uncurry_arity_aux rest 1)
-      | _ -> Some 0)
   | Ptyp_arrow (_, _, rest) -> Some (get_uncurry_arity_aux rest 1)
   | _ -> None
 

jscomp/frontend/ast_uncurry_gen.ml

@@ -91,12 +91,7 @@ let to_uncurry_fn (e : Parsetree.expression) (self : Bs_ast_mapper.mapper)
   in
   let body = Ast_async.add_async_attribute ~async body in
 
-  let len = List.length rev_extra_args in
-  let arity =
-    match rev_extra_args with
-    | [ (_, p) ] -> Ast_pat.is_unit_cont ~yes:0 ~no:len p
-    | _ -> len
-  in
+  let arity = List.length rev_extra_args in
   Bs_syntaxerr.err_large_arity loc arity;
   let fun_exp = Ast_uncurried.uncurriedFun ~loc ~arity body in
   {

jscomp/test/UncurriedExternals.js

@@ -47,7 +47,7 @@ function tsiU(c) {
     });
 }
 
-var match = React.useState(function () {
+var match = React.useState(function (param) {
       return 3;
     });
 

jscomp/test/attr_test.js

@@ -14,7 +14,7 @@ function max2(x, y) {
 var hh = 1 + 2;
 
 function f(x) {
-  des(x, (function () {
+  des(x, (function (param) {
           console.log("hei");
         }));
 }

jscomp/test/bs_auto_uncurry.js

@@ -36,28 +36,30 @@ var xs = Array.prototype.map.call([
       }));
 
 function f_0(param) {
-  return hi(function () {
+  return hi(function (param) {
 
             });
 }
 
 function f_01(param) {
-  return hi(function () {
-              console.log("x");
+  return hi(function (x) {
+              if (x === undefined) {
+                console.log("x");
+                return ;
+              }
+              
             });
 }
 
 function f_02(xs) {
-  return hi(function () {
-              xs.contents = undefined;
+  return hi(function (x) {
+              xs.contents = x;
               console.log("x");
             });
 }
 
 function f_03(xs, u) {
-  return hi(function () {
-              return Curry._1(u, undefined);
-            });
+  return hi(Curry.__1(u));
 }
 
 function fishy(x, y, z) {

jscomp/test/bs_auto_uncurry.ml

@@ -52,7 +52,7 @@ external ff2 :
     = "ff2" [@@bs.val]
 
 external
- hi: (unit -> unit [@bs.uncurry 0]) -> int = "hi" [@@bs.val]
+ hi: (unit -> unit [@bs.uncurry 1]) -> int = "hi" [@@bs.val]
 
 (** 
 fun (_){

jscomp/test/bs_auto_uncurry_test.js

@@ -37,16 +37,16 @@ var xs = {
   contents: /* [] */0
 };
 
-hi(function () {
+hi(function (x) {
       xs.contents = {
-        hd: undefined,
+        hd: x,
         tl: xs.contents
       };
     });
 
-hi(function () {
+hi(function (x) {
       xs.contents = {
-        hd: undefined,
+        hd: x,
         tl: xs.contents
       };
     });

jscomp/test/event_ffi.js

@@ -38,7 +38,7 @@ function ocaml_run(b, c) {
   return (x + b | 0) + c | 0;
 }
 
-function a0() {
+function a0(param) {
   console.log("hi");
 }
 

jscomp/test/ffi_arity_test.js

@@ -39,7 +39,7 @@ var hh = [
       return parseInt(x);
     });
 
-function u() {
+function u(param) {
   return 3;
 }
 
@@ -53,8 +53,8 @@ function fff(param) {
   vvv.contents = vvv.contents + 1 | 0;
 }
 
-function g() {
-  return fff(undefined);
+function g(param) {
+  fff(undefined);
 }
 
 function abc(x, y, z) {