Fix issue with formatting spread props.

cli/reactjs_jsx_v4.ml

@@ -188,7 +188,7 @@ let recordFromProps ~loc ~removeKey callArguments =
   let props, propsToSpread =
     removeLastPositionUnitAux callArguments []
     |> List.rev
-    |> List.partition (fun (label, _) -> label <> labelled "spreadProps")
+    |> List.partition (fun (label, _) -> label <> labelled "_spreadProps")
   in
   let props =
     if removeKey then

src/res_core.ml

@@ -2635,7 +2635,7 @@ and parseJsxProp p =
         {e with pexp_attributes = propLocAttr :: e.pexp_attributes}
       in
       (* using label "spreadProps" to distinguish from others *)
-      let label = Asttypes.Labelled "spreadProps" in
+      let label = Asttypes.Labelled "_spreadProps" in
       match p.Parser.token with
       | Rbrace ->
         Parser.next p;

src/res_printer.ml

@@ -4129,6 +4129,9 @@ and printJsxProp ~customLayout arg cmtTbl =
     | Nolabel -> Doc.nil
     | Labelled _lbl -> printIdentLike ident
     | Optional _lbl -> Doc.concat [Doc.question; printIdentLike ident])
+  | Asttypes.Labelled "_spreadProps", expr ->
+    let doc = printExpressionWithComments ~customLayout expr cmtTbl in
+    Doc.concat [Doc.lbrace; Doc.dotdotdot; Doc.softLine; doc; Doc.rbrace]
   | lbl, expr ->
     let argLoc, expr =
       match expr.pexp_attributes with

tests/parsing/grammar/expressions/expected/jsx.res.txt

@@ -577,4 +577,8 @@ let _ =
 ;;(([(((fun a -> 1))[@ns.braces ])])[@JSX ])
 ;;(([((span ~children:[] ())[@JSX ])])[@JSX ])
 ;;(([[|a|]])[@JSX ])
-;;(([(1, 2)])[@JSX ])
+;;(([(1, 2)])[@JSX ])
+let _ =
+  ((A.createElement ~x:(({js|y|js})[@ns.namedArgLoc ]) ~_spreadProps:((str)
+      [@ns.namedArgLoc ]) ~children:[] ())
+  [@JSX ])

tests/parsing/grammar/expressions/jsx.res

@@ -513,3 +513,5 @@ let _ = <View style=styles["backgroundImageWrapper"]>
 <> ...<span /> </>
 <> ...[a] </>
 <> ...(1, 2) </>
+
+let _ = <A x="y" {...str} />

tests/printer/expr/expected/jsx.res.txt

@@ -408,3 +408,5 @@ let v =
       }}
     </B>
   </A>
+
+let x = <A x="y" {...str} />

tests/printer/expr/jsx.res

@@ -401,3 +401,5 @@ let v =
       }}
     </B>
   </A>
+
+let x = <A x="y" {...str} />