Fix local type variables breaking react components in uncurried mode (rescript-lang#6668)

* test(react-ppx): breaking test for newtype in uncurried mode

* fix(react-ppx): don't ignore newtypes in uncurried mode

* docs: update changelog

* style: formatting

Author: glennsl

CHANGELOG.md

@@ -15,6 +15,7 @@
 #### :bug: Bug Fix
 
 - Fix making the static import for the dynamic import of external ffi https://github.com/rescript-lang/rescript-compiler/pull/6664
+- Fix local type variables breaking react components. https://github.com/rescript-lang/rescript-compiler/pull/6665
 
 #### :nail-care: Polish
 

jscomp/syntax/src/jsx_common.ml

@@ -58,6 +58,8 @@ let removeArity binding =
     match expr.pexp_desc with
     | _ when Ast_uncurried.exprIsUncurriedFun expr ->
       Ast_uncurried.exprExtractUncurriedFun expr
+    | Pexp_newtype (label, e) ->
+      {expr with pexp_desc = Pexp_newtype (label, removeArityRecord e)}
     | Pexp_apply (forwardRef, [(label, e)]) ->
       {
         expr with

jscomp/syntax/tests/ppx/react/expected/newtype.res.txt

@@ -99,3 +99,16 @@ let make = {
 
   \"Newtype"
 }
+
+@@uncurried
+
+module Uncurried = {
+  type props<'foo> = {foo?: 'foo}
+
+  let make = (type a, {?foo, _}: props<_>) => React.null
+  let make = {
+    let \"Newtype$Uncurried" = (props: props<_>) => make(props)
+
+    \"Newtype$Uncurried"
+  }
+}

jscomp/syntax/tests/ppx/react/newtype.res

@@ -45,4 +45,10 @@ module V4A3 = {
 }
 
 @react.component
-let make =(~x : ('a,'b), ~q:'a ) => [fst(x), q]
+let make =(~x : ('a,'b), ~q:'a ) => [fst(x), q]
+
+@@uncurried
+
+module Uncurried = {
+  @react.component
+  let make = (type a, ~foo=?) => React.null}