Initial mapping from0

Author: nojaf

compiler/ml/ast_mapper_from0.ml

@@ -358,6 +358,10 @@ module E = struct
       match_ ~loc ~attrs (sub.expr sub e) (sub.cases sub pel)
     | Pexp_try (e, pel) -> try_ ~loc ~attrs (sub.expr sub e) (sub.cases sub pel)
     | Pexp_tuple el -> tuple ~loc ~attrs (List.map (sub.expr sub) el)
+    | Pexp_construct ({txt = Longident.Lident "[]"}, None)
+      when attrs |> List.exists (fun ({txt}, _) -> txt == "JSX") ->
+      let attrs = attrs |> List.filter (fun ({txt}, _) -> txt != "JSX") in
+      jsx_fragment ~loc ~attrs loc.loc_start [] loc.loc_end
     | Pexp_construct (lid, arg) -> (
       let lid1 = map_loc sub lid in
       let arg1 = map_opt (sub.expr sub) arg in

tests/tools_tests/package-lock.json

@@ -61,3 +61,7 @@ let eq2 = 3 === 3
 
 let test = async () => 12
 let f = async () => (await test()) + 1
+
+module Fragments = {
+  let f1 = <></>
+}

tests/tools_tests/ppx/TestPpx.res

@@ -80,6 +80,10 @@ async function f() {
   return await test() + 1 | 0;
 }
 
+let Fragments = {
+  f1: /* [] */0
+};
+
 let a = "A";
 
 let b = "B";
@@ -114,4 +118,5 @@ exports.eq = eq;
 exports.eq2 = eq2;
 exports.test = test;
 exports.f = f;
+exports.Fragments = Fragments;
 /*  Not a pure module */