diff --git a/ppx/ppx.ml b/ppx/ppx.ml
index 0de6e511..efe10a1d 100644
--- a/ppx/ppx.ml
+++ b/ppx/ppx.ml
@@ -80,10 +80,9 @@ let extractChildren ?(removeLastPositionUnit = false) ~loc propsAndChildren =
     | [ (Nolabel, { pexp_desc = Pexp_construct ({ txt = Lident "()" }, None) })
       ] ->
         acc
-    | (Nolabel, _) :: _rest ->
-        raise
-          (Invalid_argument
-             "JSX: found non-labelled argument before the last position")
+    | (Nolabel, { pexp_loc }) :: _rest ->
+        Location.raise_errorf ~loc:pexp_loc
+          "JSX: found non-labelled argument before the last position"
     | arg :: rest -> allButLast_ rest (arg :: acc)
   in
   let allButLast lst = allButLast_ lst [] |> List.rev in
@@ -98,9 +97,9 @@ let extractChildren ?(removeLastPositionUnit = false) ~loc propsAndChildren =
       , if removeLastPositionUnit then allButLast props else props )
   | [ (_, childrenExpr) ], props ->
       (childrenExpr, if removeLastPositionUnit then allButLast props else props)
-  | _ ->
-      raise
-        (Invalid_argument "JSX: somehow there's more than one `children` label")
+  | _first :: (_, { pexp_loc }) :: _rest, _props ->
+      Location.raise_errorf ~loc:pexp_loc
+        "JSX: somehow there's more than one `children` label"
 
 let unerasableIgnore loc =
   { attr_name = { txt = "warning"; loc }
@@ -139,22 +138,22 @@ let filter_attr_name key attr =
   else false
 
 (* Finds the name of the variable the binding is assigned to, otherwise raises Invalid_argument *)
-let getFnName binding =
-  match binding with
-  | { pvb_pat = { ppat_desc = Ppat_var { txt } } } -> txt
-  | _ ->
-      raise (Invalid_argument "react.component calls cannot be destructured.")
+let rec getFnName = function
+  | { ppat_desc = Ppat_var { txt } } -> txt
+  | { ppat_desc = Ppat_constraint (pat, _) } -> getFnName pat
+  | { ppat_loc } ->
+      Location.raise_errorf ~loc:ppat_loc
+        "react.component calls cannot be destructured."
 
 (* Lookup the value of `props` otherwise raise Invalid_argument error *)
 let getPropsNameValue _acc (loc, exp) =
   match (loc, exp) with
   | { txt = Lident "props" }, { pexp_desc = Pexp_ident { txt = Lident str } } ->
       { propsName = str }
-  | { txt }, _ ->
-      raise
-        (Invalid_argument
-           ("react.component only accepts props as an option, given: "
-          ^ Longident.last_exn txt))
+  | { txt; loc }, _ ->
+      Location.raise_errorf ~loc
+        "react.component only accepts props as an option, given: %s"
+        (Longident.last_exn txt)
 
 (* Lookup the `props` record or string as part of [@react.component] and store the name for use when rewriting *)
 let get_props_attr payload =
@@ -174,10 +173,9 @@ let get_props_attr payload =
          }
         :: _rest)) ->
       { propsName = "props" }
-  | Some (PStr ({ pstr_desc = Pstr_eval (_, _) } :: _rest)) ->
-      raise
-        (Invalid_argument
-           "react.component accepts a record config with props as an options.")
+  | Some (PStr ({ pstr_desc = Pstr_eval (_, _); pstr_loc } :: _rest)) ->
+      Location.raise_errorf ~loc:pstr_loc
+        "react.component accepts a record config with props as an options."
   | _ -> default_props
 
 (* Plucks the label, loc, and type_ from an AST node *)
@@ -657,7 +655,7 @@ let process_value_binding ~pstr_loc ~inside_component ~mapper binding =
   if has_attr_on_binding binding || inside_component then
     let binding_loc = binding.pvb_loc in
     let binding_pat_loc = binding.pvb_pat.ppat_loc in
-    let fn_name = getFnName binding in
+    let fn_name = getFnName binding.pvb_pat in
     let modified_binding_old binding =
       let expression = binding.pvb_expr in
       (* TODO: there is a long-tail of unsupported features inside of blocks - Pexp_letmodule , Pexp_letexception , Pexp_ifthenelse *)
@@ -681,6 +679,10 @@ let process_value_binding ~pstr_loc ~inside_component ~mapper binding =
             spelunk_for_fun_expr inner_fun_expr
         | { pexp_desc = Pexp_sequence (_wrapper_expr, inner_fun_expr) } ->
             spelunk_for_fun_expr inner_fun_expr
+        | { pexp_desc = Pexp_newtype (_label, inner_fun_expr) } ->
+            spelunk_for_fun_expr inner_fun_expr
+        | { pexp_desc = Pexp_constraint (inner_fun_expr, _typ) } ->
+            spelunk_for_fun_expr inner_fun_expr
         | exp ->
             Location.raise_errorf ~loc:exp.pexp_loc
               "react.component calls can only be on function definitions or \
diff --git a/ppx/test/input_ocaml.ml b/ppx/test/input_ocaml.ml
index 0363d66b..c6cd334e 100644
--- a/ppx/test/input_ocaml.ml
+++ b/ppx/test/input_ocaml.ml
@@ -12,6 +12,8 @@ let%component make ~children:kids = div [||] kids
 let%component make ~children:(first, second) () = div [||] [ first; second ]
 let%component make ?(name = "") = div [||] [ name ]
 let%component make () = div [||] []
+let%component make (type a) ~(foo : a) : _ = div [||] []
+let%component make : type a. foo:a -> _ = fun ~foo:_ -> div [||] []
 
 let%component make ~(bar : int option) =
   div [||] [ React.string (string_of_int (Option.value ~default:0 bar)) ] ()
diff --git a/ppx/test/pp_ocaml.expected b/ppx/test/pp_ocaml.expected
index 67afc4d7..df01a8c3 100644
--- a/ppx/test/pp_ocaml.expected
+++ b/ppx/test/pp_ocaml.expected
@@ -222,6 +222,73 @@ let make =
   ((let make (Props : <  >  Js_of_ocaml.Js.t) = make () in
     fun ?key -> fun () -> React.create_element make (make_props ?key ()))
     [@merlin.hide ])
+let make =
+  let make_props
+    : foo:a ->
+        ?key:string ->
+          unit -> < foo: a Js_of_ocaml.Js.readonly_prop   >  Js_of_ocaml.Js.t
+    =
+    fun ~foo ->
+      fun ?key ->
+        fun () ->
+          let open Js_of_ocaml.Js.Unsafe in
+            obj
+              [|("key",
+                  (inject
+                     (Js_of_ocaml.Js.Optdef.option
+                        (Option.map Js_of_ocaml.Js.string key))));("foo",
+                                                                    (
+                                                                    inject
+                                                                    foo))|]
+    [@@merlin.hide ] in
+  let make (type a) ~foo:(foo : a)  = (div [||] [] : _) in
+  ((let make
+      (Props : < foo: a Js_of_ocaml.Js.readonly_prop   >  Js_of_ocaml.Js.t) =
+      make
+        ~foo:(fun (type res) -> fun (type a0) ->
+                fun (a0 : a0 Js_of_ocaml.Js.t) ->
+                  fun (_ : a0 -> < get: res   ;.. >  Js_of_ocaml.Js.gen_prop)
+                    -> (Js_of_ocaml.Js.Unsafe.get a0 "foo" : res)
+                (Props : < .. >  Js_of_ocaml.Js.t) (fun x -> x#foo)) in
+    fun ~foo ->
+      fun ?key ->
+        fun () -> React.create_element make (make_props ?key ~foo ()))
+    [@merlin.hide ])
+let make =
+  let make_props
+    : foo:'foo ->
+        ?key:string ->
+          unit ->
+            < foo: 'foo Js_of_ocaml.Js.readonly_prop   >  Js_of_ocaml.Js.t
+    =
+    fun ~foo ->
+      fun ?key ->
+        fun () ->
+          let open Js_of_ocaml.Js.Unsafe in
+            obj
+              [|("key",
+                  (inject
+                     (Js_of_ocaml.Js.Optdef.option
+                        (Option.map Js_of_ocaml.Js.string key))));("foo",
+                                                                    (
+                                                                    inject
+                                                                    foo))|]
+    [@@merlin.hide ] in
+  let make (type a) = (fun ~foo:_ -> div [||] [] : foo:a -> _) in
+  ((let make
+      (Props :
+        < foo: 'foo Js_of_ocaml.Js.readonly_prop   >  Js_of_ocaml.Js.t)
+      =
+      make
+        ~foo:(fun (type res) -> fun (type a0) ->
+                fun (a0 : a0 Js_of_ocaml.Js.t) ->
+                  fun (_ : a0 -> < get: res   ;.. >  Js_of_ocaml.Js.gen_prop)
+                    -> (Js_of_ocaml.Js.Unsafe.get a0 "foo" : res)
+                (Props : < .. >  Js_of_ocaml.Js.t) (fun x -> x#foo)) in
+    fun ~foo ->
+      fun ?key ->
+        fun () -> React.create_element make (make_props ?key ~foo ()))
+    [@merlin.hide ])
 let make =
   let make_props
     : bar:int option ->