Remove support of children spread inside JSX

CHANGELOG.md

@@ -15,6 +15,7 @@
 #### :boom: Breaking Change
 
 - Fix return type of `String.charCodeAt`. https://github.com/rescript-lang/rescript/pull/7864
+- Remove support of JSX children spread. https://github.com/rescript-lang/rescript/pull/7869
 
 #### :eyeglasses: Spec Compliance
 

analysis/src/CompletionFrontEnd.ml

@@ -1353,7 +1353,7 @@ let completionWithParser1 ~currentFile ~debug ~offset ~path ~posCursor
                 (Jsx_container_element
                    {jsx_container_element_children = children}) ->
               children
-            | _ -> JSXChildrenItems []
+            | _ -> []
           in
           let compName_loc = compName.loc in
           let compName_lid =
@@ -1412,8 +1412,7 @@ let completionWithParser1 ~currentFile ~debug ~offset ~path ~posCursor
                   (Jsx_container_element
                      {
                        jsx_container_element_closing_tag = None;
-                       jsx_container_element_children =
-                         JSXChildrenSpreading _ | JSXChildrenItems (_ :: _);
+                       jsx_container_element_children = _ :: _;
                      }) ) ->
               None
             | Some jsxProps, _ ->

analysis/src/CompletionJsx.ml

@@ -460,8 +460,8 @@ let extractJsxProps ~(compName : Longident.t Location.loc) ~props ~children =
   let open Parsetree in
   let childrenStart =
     match children with
-    | JSXChildrenItems [] -> None
-    | JSXChildrenSpreading child | JSXChildrenItems (child :: _) ->
+    | [] -> None
+    | child :: _ ->
       if child.pexp_loc.loc_ghost then None else Some (Loc.start child.pexp_loc)
   in
   let props =

analysis/src/SemanticTokens.ml

@@ -311,10 +311,7 @@ let command ~debug ~emitter ~path =
            ~pos:(Pos.ofLexing posOfGreatherthanAfterProps);
 
       (* children *)
-      (match children with
-      | Parsetree.JSXChildrenSpreading child -> iterator.expr iterator child
-      | Parsetree.JSXChildrenItems children ->
-        List.iter (iterator.expr iterator) children);
+      List.iter (iterator.expr iterator) children;
 
       (* closing tag *)
       closing_tag_opt

compiler/frontend/bs_ast_mapper.ml

@@ -292,9 +292,7 @@ module M = struct
 end
 
 module E = struct
-  let map_jsx_children sub = function
-    | JSXChildrenSpreading e -> JSXChildrenSpreading (sub.expr sub e)
-    | JSXChildrenItems xs -> JSXChildrenItems (List.map (sub.expr sub) xs)
+  let map_jsx_children sub xs = List.map (sub.expr sub) xs
 
   let map_jsx_prop sub = function
     | JSXPropPunning (optional, name) ->

compiler/ml/ast_iterator.ml

@@ -267,9 +267,7 @@ module M = struct
 end
 
 module E = struct
-  let iter_jsx_children sub = function
-    | JSXChildrenSpreading e -> sub.expr sub e
-    | JSXChildrenItems xs -> List.iter (sub.expr sub) xs
+  let iter_jsx_children sub xs = List.iter (sub.expr sub) xs
 
   let iter_jsx_prop sub = function
     | JSXPropPunning (_, name) -> iter_loc sub name

compiler/ml/ast_mapper.ml

@@ -263,9 +263,7 @@ module M = struct
 end
 
 module E = struct
-  let map_jsx_children sub = function
-    | JSXChildrenSpreading e -> JSXChildrenSpreading (sub.expr sub e)
-    | JSXChildrenItems xs -> JSXChildrenItems (List.map (sub.expr sub) xs)
+  let map_jsx_children sub xs = List.map (sub.expr sub) xs
 
   let map_jsx_prop sub = function
     | JSXPropPunning (optional, name) ->

compiler/ml/ast_mapper_from0.ml

@@ -326,8 +326,8 @@ module E = struct
     match e.pexp_desc with
     | Pexp_construct ({txt = Longident.Lident "[]" | Longident.Lident "::"}, _)
       ->
-      JSXChildrenItems (visit e)
-    | _ -> JSXChildrenSpreading (sub.expr sub e)
+      visit e
+    | _ -> [sub.expr sub e]
 
   let try_map_jsx_prop (sub : mapper) (lbl : Asttypes.Noloc.arg_label)
       (e : expression) : Parsetree.jsx_prop option =

compiler/ml/ast_mapper_to0.ml

@@ -340,8 +340,7 @@ module E = struct
 
   let map_jsx_children sub loc children =
     match children with
-    | JSXChildrenSpreading e -> sub.expr sub e
-    | JSXChildrenItems xs ->
+    | xs ->
       let list_expr = Ast_helper.Exp.make_list_expression loc xs None in
       sub.expr sub list_expr
 

compiler/ml/depend.ml

@@ -312,9 +312,7 @@ let rec add_expr bv exp =
     and_jsx_props bv props;
     add_jsx_children bv children
 
-and add_jsx_children bv = function
-  | JSXChildrenSpreading e -> add_expr bv e
-  | JSXChildrenItems xs -> List.iter (add_expr bv) xs
+and add_jsx_children bv xs = List.iter (add_expr bv) xs
 
 and add_jsx_prop bv = function
   | JSXPropPunning (_, _) -> ()

compiler/ml/parsetree.ml

@@ -372,9 +372,7 @@ and jsx_prop =
       Location.t
       * expression
 
-and jsx_children =
-  | JSXChildrenSpreading of expression
-  | JSXChildrenItems of expression list
+and jsx_children = expression list
 
 and jsx_props = jsx_prop list
 

compiler/ml/pprintast.ml

@@ -798,7 +798,7 @@ and simple_expr ctxt f x =
       pp f fmt (pattern ctxt) s expression e1 direction_flag df expression e2
         expression e3
     | Pexp_jsx_element (Jsx_fragment {jsx_fragment_children = children}) ->
-      pp f "<>%a</>" (list (simple_expr ctxt)) (collect_jsx_children children)
+      pp f "<>%a</>" (list (simple_expr ctxt)) children
     | Pexp_jsx_element
         (Jsx_unary_element
            {
@@ -828,21 +828,13 @@ and simple_expr ctxt f x =
       in
       match props with
       | [] ->
-        pp f "<%s>%a%s" name
-          (list (simple_expr ctxt))
-          (collect_jsx_children children)
-          closing_name
+        pp f "<%s>%a%s" name (list (simple_expr ctxt)) children closing_name
       | _ ->
         pp f "<%s %a>%a%s" name (print_jsx_props ctxt) props
           (list (simple_expr ctxt))
-          (collect_jsx_children children)
-          closing_name)
+          children closing_name)
     | _ -> paren true (expression ctxt) f x
 
-and collect_jsx_children = function
-  | JSXChildrenSpreading e -> [e]
-  | JSXChildrenItems xs -> xs
-
 and print_jsx_prop ctxt f = function
   | JSXPropPunning (is_optional, name) ->
     pp f "%s" (if is_optional then "?" ^ name.txt else name.txt)

compiler/ml/printast.ml

@@ -383,9 +383,7 @@ and expression i ppf x =
 
 and jsx_children i ppf children =
   line i ppf "jsx_children =\n";
-  match children with
-  | JSXChildrenSpreading e -> expression (i + 1) ppf e
-  | JSXChildrenItems xs -> list (i + 1) expression ppf xs
+  list (i + 1) expression ppf children
 
 and jsx_prop i ppf = function
   | JSXPropPunning (opt, name) ->

compiler/syntax/src/jsx_v4.ml

@@ -1182,8 +1182,8 @@ let append_children_prop (config : Jsx_common.jsx_config) mapper
     (component_description : componentDescription) (props : jsx_props)
     (children : jsx_children) : jsx_props =
   match children with
-  | JSXChildrenItems [] -> props
-  | JSXChildrenItems [child] | JSXChildrenSpreading child ->
+  | [] -> props
+  | [child] ->
     let expr =
       (* I don't quite know why fragment and uppercase don't do this additional ReactDOM.someElement wrapping *)
       match component_description with
@@ -1209,7 +1209,7 @@ let append_children_prop (config : Jsx_common.jsx_config) mapper
         JSXPropValue
           ({txt = "children"; loc = child.pexp_loc}, is_optional, expr);
       ]
-  | JSXChildrenItems (head :: _ as xs) ->
+  | head :: _ as xs ->
     let loc =
       match List.rev xs with
       | [] -> head.pexp_loc
@@ -1230,11 +1230,7 @@ let append_children_prop (config : Jsx_common.jsx_config) mapper
 let mk_react_jsx (config : Jsx_common.jsx_config) mapper loc attrs
     (component_description : componentDescription) (elementTag : expression)
     (props : jsx_props) (children : jsx_children) : expression =
-  let more_than_one_children =
-    match children with
-    | JSXChildrenSpreading _ -> false
-    | JSXChildrenItems xs -> List.length xs > 1
-  in
+  let more_than_one_children = List.length children > 1 in
   let props_with_children =
     append_children_prop config mapper component_description props children
   in
@@ -1314,12 +1310,12 @@ let expr ~(config : Jsx_common.jsx_config) mapper expression =
         (* For example 'input' *)
         let component_name_expr = constant_string ~loc:tag_loc name in
         mk_react_jsx config mapper loc attrs LowercasedComponent
-          component_name_expr props (JSXChildrenItems [])
+          component_name_expr props []
       | JsxUpperTag _ | JsxQualifiedLowerTag _ ->
         (* MyModule.make *)
         let make_id = mk_uppercase_tag_name_expr tag_name in
         mk_react_jsx config mapper loc attrs UppercasedComponent make_id props
-          (JSXChildrenItems [])
+          []
       | JsxTagInvalid name ->
         Jsx_common.raise_error ~loc
           "JSX: element name is neither upper- or lowercase, got \"%s\"" name)

compiler/syntax/src/res_ast_debugger.ml

@@ -707,12 +707,7 @@ module SexpAst = struct
       | Pexp_extension ext ->
         Sexp.list [Sexp.atom "Pexp_extension"; extension ext]
       | Pexp_await e -> Sexp.list [Sexp.atom "Pexp_await"; expression e]
-      | Pexp_jsx_element (Jsx_fragment {jsx_fragment_children = children}) ->
-        let xs =
-          match children with
-          | JSXChildrenSpreading e -> [e]
-          | JSXChildrenItems xs -> xs
-        in
+      | Pexp_jsx_element (Jsx_fragment {jsx_fragment_children = xs}) ->
         Sexp.list
           [
             Sexp.atom "Pexp_jsx_fragment"; Sexp.list (map_empty ~f:expression xs);
@@ -728,13 +723,8 @@ module SexpAst = struct
           (Jsx_container_element
              {
                jsx_container_element_props = props;
-               jsx_container_element_children = children;
+               jsx_container_element_children = xs;
              }) ->
-        let xs =
-          match children with
-          | JSXChildrenSpreading e -> [e]
-          | JSXChildrenItems xs -> xs
-        in
         Sexp.list
           [
             Sexp.atom "Pexp_jsx_container_element";

compiler/syntax/src/res_comments_table.ml

@@ -1658,12 +1658,7 @@ and walk_expression expr t comments =
     let opening_token = {expr.pexp_loc with loc_end = opening_greater_than} in
     let on_same_line, rest = partition_by_on_same_line opening_token comments in
     attach t.trailing opening_token on_same_line;
-    let exprs =
-      match children with
-      | Parsetree.JSXChildrenSpreading e -> [e]
-      | Parsetree.JSXChildrenItems xs -> xs
-    in
-    let xs = exprs |> List.map (fun e -> Expression e) in
+    let xs = children |> List.map (fun e -> Expression e) in
     walk_list xs t rest
   | Pexp_jsx_element
       (Jsx_unary_element
@@ -1769,7 +1764,7 @@ and walk_expression expr t comments =
         partition_leading_trailing rest closing_tag_loc
     in
     match children with
-    | Parsetree.JSXChildrenItems [] -> (
+    | [] -> (
       (* attach all comments to the closing tag if there are no children *)
       match closing_tag with
       | None ->
@@ -1801,11 +1796,7 @@ and walk_expression expr t comments =
           (* if the closing tag is on the same line, attach comments to the opening tag *)
           attach t.leading closing_tag_loc comments_for_children)
     | children ->
-      let children_nodes =
-        match children with
-        | Parsetree.JSXChildrenSpreading e -> [Expression e]
-        | Parsetree.JSXChildrenItems xs -> List.map (fun e -> Expression e) xs
-      in
+      let children_nodes = List.map (fun e -> Expression e) children in
 
       walk_list children_nodes t comments_for_children
     (* It is less likely that there are comments inside the closing tag, 

compiler/syntax/src/res_core.ml

@@ -188,6 +188,9 @@ module ErrorMessages = struct
   let type_definition_in_function =
     "Type definitions are not allowed inside functions.\n"
     ^ "  Move this `type` declaration to the top level or into a module."
+
+  let spread_children_no_longer_supported =
+    "Spreading JSX children is no longer supported."
 end
 
 module InExternal = struct
@@ -2999,19 +3002,13 @@ and parse_jsx_children p : Parsetree.jsx_children =
       loop p (child :: children)
     | _ -> children
   in
-  let children =
-    match p.Parser.token with
-    | DotDotDot ->
-      Parser.next p;
-      let expr =
-        parse_primary_expr ~operand:(parse_atomic_expr p) ~no_call:true p
-      in
-      Parsetree.JSXChildrenSpreading expr
-    | _ ->
-      let children = List.rev (loop p []) in
-      Parsetree.JSXChildrenItems children
-  in
-  children
+  match p.Parser.token with
+  | DotDotDot ->
+    Parser.err ~start_pos:p.start_pos ~end_pos:p.end_pos p
+      (Diagnostics.message ErrorMessages.spread_children_no_longer_supported);
+    Parser.next p;
+    [parse_primary_expr ~operand:(parse_atomic_expr p) ~no_call:true p]
+  | _ -> List.rev (loop p [])
 
 and parse_braced_or_record_expr p =
   let start_pos = p.Parser.start_pos in

compiler/syntax/src/res_printer.ml

@@ -4516,8 +4516,8 @@ and print_jsx_container_tag ~state tag_name
   (* <div className="test" /> *)
   let has_children =
     match children with
-    | JSXChildrenSpreading _ | JSXChildrenItems (_ :: _) -> true
-    | JSXChildrenItems [] -> false
+    | _ :: _ -> true
+    | [] -> false
   in
   let line_sep = get_line_sep_for_jsx_children children in
   let print_children children =
@@ -4606,8 +4606,8 @@ and print_jsx_fragment ~state (opening_greater_than : Lexing.position)
   in
   let has_children =
     match children with
-    | JSXChildrenItems [] -> false
-    | JSXChildrenSpreading _ | JSXChildrenItems (_ :: _) -> true
+    | [] -> false
+    | _ :: _ -> true
   in
   let line_sep = get_line_sep_for_jsx_children children in
   Doc.group
@@ -4621,18 +4621,15 @@ and print_jsx_fragment ~state (opening_greater_than : Lexing.position)
        ])
 
 and get_line_sep_for_jsx_children (children : Parsetree.jsx_children) =
-  match children with
-  | JSXChildrenSpreading _ -> Doc.line
-  | JSXChildrenItems children ->
-    if
-      List.length children > 1
-      || List.exists
-           (function
-             | {Parsetree.pexp_desc = Pexp_jsx_element _} -> true
-             | _ -> false)
-           children
-    then Doc.hard_line
-    else Doc.line
+  if
+    List.length children > 1
+    || List.exists
+         (function
+           | {Parsetree.pexp_desc = Pexp_jsx_element _} -> true
+           | _ -> false)
+         children
+  then Doc.hard_line
+  else Doc.line
 
 and print_jsx_children ~state (children : Parsetree.jsx_children) cmt_tbl =
   let open Parsetree in
@@ -4669,9 +4666,8 @@ and print_jsx_children ~state (children : Parsetree.jsx_children) cmt_tbl =
       print_comments (add_parens_or_braces expr_doc) cmt_tbl braces_loc
   in
   match children with
-  | JSXChildrenItems [] -> Doc.nil
-  | JSXChildrenSpreading child -> Doc.concat [Doc.dotdotdot; print_expr child]
-  | JSXChildrenItems children ->
+  | [] -> Doc.nil
+  | children ->
     let rec visit acc children =
       match children with
       | [] -> acc

tests/syntax_tests/data/conversion/reason/expected/jsxProps.res.txt

@@ -7,11 +7,3 @@ let handleClick = (href, event) =>
 @react.component
 let make = (~href, ~className="", ~children) =>
   <a href className onClick={event => handleClick(href, event)}> children </a>
-
-<Animated> ...{x => <div />} </Animated>
-
-<div> ...element </div>
-<div> ...{a => 1} </div>
-<div> ...<span /> </div>
-<div> ...[a, b] </div>
-<div> ...{(1, 2)} </div>