Fix forwardRef in uncurried mode (#6447)

Author: mununki

CHANGELOG.md

@@ -22,6 +22,7 @@
 - Fix issue where GenType was not supporting `@tag` on ordinary variatns https://github.com/rescript-lang/rescript-compiler/pull/6437
 - Fix using dynamic import of module in block instead of async function https://github.com/rescript-lang/rescript-compiler/pull/6434
 - Fix issue with using dynamic import of module in uncurried mode https://github.com/rescript-lang/rescript-compiler/pull/6434
+- Fix build error where JSX v4 transformation of the discouraged forwardRef in uncurried mode https://github.com/rescript-lang/rescript-compiler/pull/6447
 
 #### :nail_care: Polish
 

jscomp/syntax/src/reactjs_jsx_v4.ml

@@ -968,7 +968,8 @@ let mapBinding ~config ~emptyLoc ~pstr_loc ~fileName ~recFlag binding =
     let fullExpression =
       if !Config.uncurried = Uncurried then
         fullExpression
-        |> Ast_uncurried.uncurriedFun ~loc:fullExpression.pexp_loc ~arity:1
+        |> Ast_uncurried.uncurriedFun ~loc:fullExpression.pexp_loc
+             ~arity:(if hasForwardRef then 2 else 1)
       else fullExpression
     in
     let fullExpression =