diff --git a/CHANGELOG.md b/CHANGELOG.md
index 14c3b02f..7ad54874 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -64,6 +64,7 @@
 - Fix issue with using alias and default value together https://github.com/rescript-lang/syntax/pull/734
 - Fix formatting of `switch` expressions that contain braced `cases` inside https://github.com/rescript-lang/syntax/pull/735
 - Fix formatting of props spread for multiline JSX expression https://github.com/rescript-lang/syntax/pull/736
+- Fix issue with JSX V4 and newtype https://github.com/rescript-lang/syntax/pull/737
 
 #### :eyeglasses: Spec Compliance
 
diff --git a/cli/reactjs_jsx_v4.ml b/cli/reactjs_jsx_v4.ml
index c53a467d..b4a3b932 100644
--- a/cli/reactjs_jsx_v4.ml
+++ b/cli/reactjs_jsx_v4.ml
@@ -277,7 +277,7 @@ let makePropsTypeParams ?(stripExplicitOption = false)
                 For example, if JSX ppx is used for React Native, type would be different.
              *)
            match interiorType with
-           | {ptyp_desc = Ptyp_var "ref"} -> Some (refType loc)
+           | {ptyp_desc = Ptyp_any} -> Some (refType loc)
            | _ ->
              (* Strip explicit Js.Nullable.t in case of forwardRef *)
              if stripExplicitJsNullableOfRef then stripJsNullable interiorType
@@ -687,46 +687,18 @@ let rec recursivelyTransformNamedArgsForMake mapper expr args newtypes coreType
       (Some coreType)
   | _ -> (args, newtypes, coreType)
 
-let newtypeToVar newtype type_ =
-  let var_desc = Ptyp_var ("type-" ^ newtype) in
-  let typ (mapper : Ast_mapper.mapper) typ =
-    match typ.ptyp_desc with
-    | Ptyp_constr ({txt = Lident name}, _) when name = newtype ->
-      {typ with ptyp_desc = var_desc}
-    | _ -> Ast_mapper.default_mapper.typ mapper typ
-  in
-  let mapper = {Ast_mapper.default_mapper with typ} in
-  mapper.typ mapper type_
-
-let argToType ~newtypes ~(typeConstraints : core_type option) types
+let argToType types
     ((name, default, {ppat_attributes = attrs}, _alias, loc, type_) :
       arg_label * expression option * pattern * label * 'loc * core_type option)
     =
-  let rec getType name coreType =
-    match coreType with
-    | {ptyp_desc = Ptyp_arrow (arg, c1, c2)} ->
-      if name = arg then Some c1 else getType name c2
-    | _ -> None
-  in
-  let typeConst = Option.bind typeConstraints (getType name) in
-  let type_ =
-    List.fold_left
-      (fun type_ newtype ->
-        match (type_, typeConst) with
-        | _, Some typ | Some typ, None -> Some (newtypeToVar newtype.txt typ)
-        | _ -> None)
-      type_ newtypes
-  in
   match (type_, name, default) with
   | Some type_, name, _ when isOptional name ->
     (true, getLabel name, attrs, loc, type_) :: types
   | Some type_, name, _ -> (false, getLabel name, attrs, loc, type_) :: types
   | None, name, _ when isOptional name ->
-    (true, getLabel name, attrs, loc, Typ.var ~loc (safeTypeFromValue name))
-    :: types
+    (true, getLabel name, attrs, loc, Typ.any ~loc ()) :: types
   | None, name, _ when isLabelled name ->
-    (false, getLabel name, attrs, loc, Typ.var ~loc (safeTypeFromValue name))
-    :: types
+    (false, getLabel name, attrs, loc, Typ.any ~loc ()) :: types
   | _ -> types
 
 let hasDefaultValue nameArgList =
@@ -1006,16 +978,12 @@ let transformStructureItem ~config mapper item =
             modifiedBinding binding
           in
           (* do stuff here! *)
-          let namedArgList, newtypes, typeConstraints =
+          let namedArgList, newtypes, _typeConstraints =
             recursivelyTransformNamedArgsForMake mapper
               (modifiedBindingOld binding)
               [] [] None
           in
-          let namedTypeList =
-            List.fold_left
-              (argToType ~newtypes ~typeConstraints)
-              [] namedArgList
-          in
+          let namedTypeList = List.fold_left argToType [] namedArgList in
           let vbMatch (name, default, _, alias, loc, _) =
             let label = getLabel name in
             match default with
@@ -1208,6 +1176,13 @@ let transformStructureItem ~config mapper item =
                       | _ -> [Typ.any ()]))))
               expression
           in
+          let expression =
+            (* Add new tupes (type a,b,c) to make's definition *)
+            newtypes
+            |> List.fold_left
+                 (fun e newtype -> Exp.newtype newtype e)
+                 expression
+          in
           (* let make = ({id, name, ...}: props<'id, 'name, ...>) => { ... } *)
           let bindings, newBinding =
             match recFlag with
diff --git a/tests/ppx/react/expected/aliasProps.res.txt b/tests/ppx/react/expected/aliasProps.res.txt
index ece2f660..3857f28f 100644
--- a/tests/ppx/react/expected/aliasProps.res.txt
+++ b/tests/ppx/react/expected/aliasProps.res.txt
@@ -4,7 +4,7 @@ module C0 = {
   type props<'priority, 'text> = {priority: 'priority, text?: 'text}
 
   @react.component
-  let make = (props: props<'priority, 'text>) => {
+  let make = (props: props<_, _>) => {
     let _ = props.priority
     let text = switch props.text {
     | Some(text) => text
@@ -24,7 +24,7 @@ module C1 = {
   type props<'priority, 'text> = {priority: 'priority, text?: 'text}
 
   @react.component
-  let make = (props: props<'priority, 'text>) => {
+  let make = (props: props<_, _>) => {
     let p = props.priority
     let text = switch props.text {
     | Some(text) => text
@@ -44,7 +44,7 @@ module C2 = {
   type props<'foo> = {foo?: 'foo}
 
   @react.component
-  let make = (props: props<'foo>) => {
+  let make = (props: props<_>) => {
     let bar = switch props.foo {
     | Some(foo) => foo
     | None => ""
diff --git a/tests/ppx/react/expected/commentAtTop.res.txt b/tests/ppx/react/expected/commentAtTop.res.txt
index 4c7eba77..af2649b0 100644
--- a/tests/ppx/react/expected/commentAtTop.res.txt
+++ b/tests/ppx/react/expected/commentAtTop.res.txt
@@ -1,7 +1,7 @@
 type props<'msg> = {msg: 'msg} // test React JSX file
 
 @react.component
-let make = ({msg, _}: props<'msg>) => {
+let make = ({msg, _}: props<_>) => {
   ReactDOM.jsx("div", {children: ?ReactDOM.someElement({msg->React.string})})
 }
 let make = {
diff --git a/tests/ppx/react/expected/defaultValueProp.res.txt b/tests/ppx/react/expected/defaultValueProp.res.txt
index dc8f002c..a72ee93b 100644
--- a/tests/ppx/react/expected/defaultValueProp.res.txt
+++ b/tests/ppx/react/expected/defaultValueProp.res.txt
@@ -1,7 +1,7 @@
 module C0 = {
   type props<'a, 'b> = {a?: 'a, b?: 'b}
   @react.component
-  let make = (props: props<'a, 'b>) => {
+  let make = (props: props<_, _>) => {
     let a = switch props.a {
     | Some(a) => a
     | None => 2
@@ -23,7 +23,7 @@ module C1 = {
   type props<'a, 'b> = {a?: 'a, b: 'b}
 
   @react.component
-  let make = (props: props<'a, 'b>) => {
+  let make = (props: props<_, _>) => {
     let a = switch props.a {
     | Some(a) => a
     | None => 2
diff --git a/tests/ppx/react/expected/fileLevelConfig.res.txt b/tests/ppx/react/expected/fileLevelConfig.res.txt
index c1f3c9d1..4927786e 100644
--- a/tests/ppx/react/expected/fileLevelConfig.res.txt
+++ b/tests/ppx/react/expected/fileLevelConfig.res.txt
@@ -21,7 +21,7 @@ module V4C = {
   type props<'msg> = {msg: 'msg}
 
   @react.component
-  let make = ({msg, _}: props<'msg>) => {
+  let make = ({msg, _}: props<_>) => {
     ReactDOM.createDOMElementVariadic("div", [{msg->React.string}])
   }
   let make = {
@@ -37,7 +37,7 @@ module V4A = {
   type props<'msg> = {msg: 'msg}
 
   @react.component
-  let make = ({msg, _}: props<'msg>) => {
+  let make = ({msg, _}: props<_>) => {
     ReactDOM.jsx("div", {children: ?ReactDOM.someElement({msg->React.string})})
   }
   let make = {
diff --git a/tests/ppx/react/expected/firstClassModules.res.txt b/tests/ppx/react/expected/firstClassModules.res.txt
index c55d9e8b..689760fc 100644
--- a/tests/ppx/react/expected/firstClassModules.res.txt
+++ b/tests/ppx/react/expected/firstClassModules.res.txt
@@ -66,11 +66,12 @@ module Select = {
 
   @react.component
   let make = (
+    type a key,
     {model, selected, onChange, items, _}: props<
-      module(T with type t = '\"type-a" and type key = '\"type-key"),
-      option<'\"type-key">,
-      option<'\"type-key"> => unit,
-      array<'\"type-a">,
+      module(T with type t = a and type key = key),
+      option<key>,
+      option<key> => unit,
+      array<a>,
     >,
   ) => {
     let _ = (model, selected, onChange, items)
diff --git a/tests/ppx/react/expected/forwardRef.res.txt b/tests/ppx/react/expected/forwardRef.res.txt
index cb7b143f..a26c2fae 100644
--- a/tests/ppx/react/expected/forwardRef.res.txt
+++ b/tests/ppx/react/expected/forwardRef.res.txt
@@ -77,7 +77,7 @@ module V4C = {
 
     @react.component
     let make = (
-      {?className, children, _}: props<'className, 'children, ReactRef.currentDomRef>,
+      {?className, children, _}: props<_, _, ReactRef.currentDomRef>,
       ref: Js.Nullable.t<ReactRef.currentDomRef>,
     ) =>
       ReactDOM.createDOMElementVariadic(
@@ -135,10 +135,7 @@ module V4A = {
     }
 
     @react.component
-    let make = (
-      {?className, children, _}: props<'className, 'children, ReactDOM.Ref.currentDomRef>,
-      ref,
-    ) =>
+    let make = ({?className, children, _}: props<_, _, ReactDOM.Ref.currentDomRef>, ref) =>
       ReactDOM.jsxs(
         "div",
         {
diff --git a/tests/ppx/react/expected/interface.res.txt b/tests/ppx/react/expected/interface.res.txt
index 9b6062dd..77c60724 100644
--- a/tests/ppx/react/expected/interface.res.txt
+++ b/tests/ppx/react/expected/interface.res.txt
@@ -1,6 +1,6 @@
 module A = {
   type props<'x> = {x: 'x}
-  @react.component let make = ({x, _}: props<'x>) => React.string(x)
+  @react.component let make = ({x, _}: props<_>) => React.string(x)
   let make = {
     let \"Interface$A" = (props: props<_>) => make(props)
     \"Interface$A"
diff --git a/tests/ppx/react/expected/mangleKeyword.res.txt b/tests/ppx/react/expected/mangleKeyword.res.txt
index e216b703..f5642f49 100644
--- a/tests/ppx/react/expected/mangleKeyword.res.txt
+++ b/tests/ppx/react/expected/mangleKeyword.res.txt
@@ -23,8 +23,7 @@ module C4C0 = {
   type props<'T_open, 'T_type> = {@as("open") _open: 'T_open, @as("type") _type: 'T_type}
 
   @react.component
-  let make = ({@as("open") _open, @as("type") _type, _}: props<'T_open, string>) =>
-    React.string(_open)
+  let make = ({@as("open") _open, @as("type") _type, _}: props<_, string>) => React.string(_open)
   let make = {
     let \"MangleKeyword$C4C0" = (props: props<_>) => make(props)
 
@@ -46,8 +45,7 @@ module C4A0 = {
   type props<'T_open, 'T_type> = {@as("open") _open: 'T_open, @as("type") _type: 'T_type}
 
   @react.component
-  let make = ({@as("open") _open, @as("type") _type, _}: props<'T_open, string>) =>
-    React.string(_open)
+  let make = ({@as("open") _open, @as("type") _type, _}: props<_, string>) => React.string(_open)
   let make = {
     let \"MangleKeyword$C4A0" = (props: props<_>) => make(props)
 
diff --git a/tests/ppx/react/expected/newtype.res.txt b/tests/ppx/react/expected/newtype.res.txt
index fb810ec5..178ce71d 100644
--- a/tests/ppx/react/expected/newtype.res.txt
+++ b/tests/ppx/react/expected/newtype.res.txt
@@ -27,7 +27,7 @@ module V4C = {
   type props<'a, 'b, 'c> = {a: 'a, b: 'b, c: 'c}
 
   @react.component
-  let make = ({a, b, c, _}: props<'\"type-a", array<option<[#Foo('\"type-a")]>>, 'a>) =>
+  let make = (type a, {a, b, c, _}: props<a, array<option<[#Foo(a)]>>, 'a>) =>
     ReactDOM.createDOMElementVariadic("div", [])
   let make = {
     let \"Newtype$V4C" = (props: props<_>) => make(props)
@@ -42,7 +42,7 @@ module V4A = {
   type props<'a, 'b, 'c> = {a: 'a, b: 'b, c: 'c}
 
   @react.component
-  let make = ({a, b, c, _}: props<'\"type-a", array<option<[#Foo('\"type-a")]>>, 'a>) =>
+  let make = (type a, {a, b, c, _}: props<a, array<option<[#Foo(a)]>>, 'a>) =>
     ReactDOM.jsx("div", {})
   let make = {
     let \"Newtype$V4A" = (props: props<_>) => make(props)
@@ -50,3 +50,49 @@ module V4A = {
     \"Newtype$V4A"
   }
 }
+
+module V4A1 = {
+  type props<'a, 'b, 'c> = {a: 'a, b: 'b, c: 'c}
+
+  @react.component
+  let make = (type x y, {a, b, c, _}: props<x, array<y>, 'a>) => ReactDOM.jsx("div", {})
+  let make = {
+    let \"Newtype$V4A1" = (props: props<_>) => make(props)
+
+    \"Newtype$V4A1"
+  }
+}
+
+module type T = {
+  type t
+}
+
+module V4A2 = {
+  type props<'foo> = {foo: 'foo}
+
+  @react.component
+  let make = (type a, {foo, _}: props<module(T with type t = a)>) => {
+    module T = unpack(foo)
+    ReactDOM.jsx("div", {})
+  }
+  let make = {
+    let \"Newtype$V4A2" = (props: props<_>) => make(props)
+
+    \"Newtype$V4A2"
+  }
+}
+
+module V4A3 = {
+  type props<'foo> = {foo: 'foo}
+
+  @react.component
+  let make = (type a, {foo, _}: props<_>) => {
+    module T = unpack(foo: T with type t = a)
+    foo
+  }
+  let make = {
+    let \"Newtype$V4A3" = (props: props<_>) => make(props)
+
+    \"Newtype$V4A3"
+  }
+}
diff --git a/tests/ppx/react/expected/optimizeAutomaticMode.res.txt b/tests/ppx/react/expected/optimizeAutomaticMode.res.txt
index 25c30a12..5234e02a 100644
--- a/tests/ppx/react/expected/optimizeAutomaticMode.res.txt
+++ b/tests/ppx/react/expected/optimizeAutomaticMode.res.txt
@@ -7,7 +7,7 @@ module User = {
   type props<'doctor> = {doctor: 'doctor}
 
   @react.component
-  let make = ({doctor, _}: props<'doctor>) => {
+  let make = ({doctor, _}: props<_>) => {
     ReactDOM.jsx("h1", {id: "h1", children: ?ReactDOM.someElement({React.string(format(doctor))})})
   }
   let make = {
diff --git a/tests/ppx/react/expected/removedKeyProp.res.txt b/tests/ppx/react/expected/removedKeyProp.res.txt
index a7e5a464..83d11e9b 100644
--- a/tests/ppx/react/expected/removedKeyProp.res.txt
+++ b/tests/ppx/react/expected/removedKeyProp.res.txt
@@ -3,7 +3,7 @@
 module Foo = {
   type props<'x, 'y> = {x: 'x, y: 'y}
 
-  @react.component let make = ({x, y, _}: props<'x, 'y>) => React.string(x ++ y)
+  @react.component let make = ({x, y, _}: props<_, _>) => React.string(x ++ y)
   let make = {
     let \"RemovedKeyProp$Foo" = (props: props<_>) => make(props)
 
@@ -15,7 +15,7 @@ module HasChildren = {
   type props<'children> = {children: 'children}
 
   @react.component
-  let make = ({children, _}: props<'children>) => ReactDOM.createElement(React.fragment, [children])
+  let make = ({children, _}: props<_>) => ReactDOM.createElement(React.fragment, [children])
   let make = {
     let \"RemovedKeyProp$HasChildren" = (props: props<_>) => make(props)
 
diff --git a/tests/ppx/react/expected/topLevel.res.txt b/tests/ppx/react/expected/topLevel.res.txt
index bf6f95ec..5268d7e8 100644
--- a/tests/ppx/react/expected/topLevel.res.txt
+++ b/tests/ppx/react/expected/topLevel.res.txt
@@ -25,7 +25,7 @@ module V4C = {
   type props<'a, 'b> = {a: 'a, b: 'b}
 
   @react.component
-  let make = ({a, b, _}: props<'a, 'b>) => {
+  let make = ({a, b, _}: props<_, _>) => {
     Js.log("This function should be named 'TopLevel.react'")
     ReactDOM.createDOMElementVariadic("div", [])
   }
@@ -42,7 +42,7 @@ module V4A = {
   type props<'a, 'b> = {a: 'a, b: 'b}
 
   @react.component
-  let make = ({a, b, _}: props<'a, 'b>) => {
+  let make = ({a, b, _}: props<_, _>) => {
     Js.log("This function should be named 'TopLevel.react'")
     ReactDOM.jsx("div", {})
   }
diff --git a/tests/ppx/react/expected/typeConstraint.res.txt b/tests/ppx/react/expected/typeConstraint.res.txt
index e7b3e483..1ce2faaf 100644
--- a/tests/ppx/react/expected/typeConstraint.res.txt
+++ b/tests/ppx/react/expected/typeConstraint.res.txt
@@ -20,8 +20,7 @@ module V4C = {
   type props<'a, 'b> = {a: 'a, b: 'b}
 
   @react.component
-  let make = ({a, b, _}: props<'\"type-a", '\"type-a">) =>
-    ReactDOM.createDOMElementVariadic("div", [])
+  let make = (type a, {a, b, _}: props<_, _>) => ReactDOM.createDOMElementVariadic("div", [])
   let make = {
     let \"TypeConstraint$V4C" = (props: props<_>) => make(props)
 
@@ -34,7 +33,7 @@ module V4C = {
 module V4A = {
   type props<'a, 'b> = {a: 'a, b: 'b}
 
-  @react.component let make = ({a, b, _}: props<'\"type-a", '\"type-a">) => ReactDOM.jsx("div", {})
+  @react.component let make = (type a, {a, b, _}: props<_, _>) => ReactDOM.jsx("div", {})
   let make = {
     let \"TypeConstraint$V4A" = (props: props<_>) => make(props)
 
diff --git a/tests/ppx/react/expected/v4.res.txt b/tests/ppx/react/expected/v4.res.txt
index 9e709259..7412b812 100644
--- a/tests/ppx/react/expected/v4.res.txt
+++ b/tests/ppx/react/expected/v4.res.txt
@@ -9,7 +9,7 @@ module AnotherName = {
   type // Component with another name than "make"
   props<'x> = {x: 'x}
 
-  @react.component let anotherName = ({x, _}: props<'x>) => React.string(x)
+  @react.component let anotherName = ({x, _}: props<_>) => React.string(x)
   let anotherName = {
     let \"V4$AnotherName$anotherName" = (props: props<_>) => anotherName(props)
 
diff --git a/tests/ppx/react/newtype.res b/tests/ppx/react/newtype.res
index 27a834eb..c77634ed 100644
--- a/tests/ppx/react/newtype.res
+++ b/tests/ppx/react/newtype.res
@@ -18,3 +18,28 @@ module V4A = {
   @react.component
   let make = (type a, ~a: a, ~b: array<option<[#Foo(a)]>>, ~c: 'a, _) => <div />
 }
+
+module V4A1 = {
+  @react.component
+  let make = (type x y, ~a:x, ~b:array<y>, ~c:'a) => <div />
+}
+
+module type T = {
+  type t
+}
+
+module V4A2 = {
+  @react.component
+  let make = (type a, ~foo: module(T with type t = a)) => {
+    module T = unpack(foo)
+    <div />
+  }
+}
+
+module V4A3 = {
+  @react.component
+  let make = (type a, ~foo) => {
+    module T = unpack(foo: T with type t = a)
+    foo
+  }
+}