Fix issue with nested async functions, where the inner function would be emitted without async

Author: cristianoc

CHANGELOG.md

@@ -15,8 +15,11 @@
 #### :nail_care: Polish
 
 - Add the gap property to jsxDOMStyle https://github.com/rescript-lang/rescript-compiler/pull/5956
+
+#### :bug: Bug Fix
 - Fix issue where error messages related to non-existent props were displayed without location information https://github.com/rescript-lang/syntax/pull/730
 - Fix issue where uncurried functions were incorrectly converting the type of a prop given as a default value to curried https://github.com/rescript-lang/syntax/pull/731
+- Fix issue with nested async functions, where the inner function would be emitted without `async`
 
 # 10.1.2
 

jscomp/ml/translcore.ml

@@ -681,6 +681,8 @@ let rec cut n l =
 
 let try_ids = Hashtbl.create 8
 
+let has_async_attribute exp = exp.exp_attributes |> List.exists (fun ({txt}, _payload) -> txt = "res.async")
+
 let rec transl_exp e =
   List.iter (Translattribute.check_attribute e) e.exp_attributes;
   transl_exp0 e
@@ -695,7 +697,7 @@ and transl_exp0 (e : Typedtree.expression) : Lambda.lambda =
   | Texp_let (rec_flag, pat_expr_list, body) ->
       transl_let rec_flag pat_expr_list (transl_exp body)
   | Texp_function { arg_label = _; param; cases; partial } ->
-      let async = e.exp_attributes |> List.exists (fun ({txt}, _payload) -> txt = "res.async") in
+      let async = has_async_attribute e in
       let params, body, return_unit =
         let pl = push_defaults e.exp_loc [] cases partial in
         transl_function e.exp_loc partial param pl
@@ -1021,7 +1023,7 @@ and transl_function loc partial param cases =
        } as exp;
    };
   ]
-    when Parmatch.inactive ~partial pat ->
+    when Parmatch.inactive ~partial pat && not (exp |> has_async_attribute) ->
       let params, body, return_unit =
         transl_function exp.exp_loc partial' param' cases
       in

jscomp/test/async_inline.js

@@ -38,10 +38,24 @@ async function broken$1(someAsyncFunction) {
 
 var broken$2 = broken$1;
 
+function nested1(param) {
+  return async function (y) {
+    return await y;
+  };
+}
+
+async function nested2(param) {
+  return async function (y) {
+    return await y;
+  };
+}
+
 exports.willBeInlined = willBeInlined;
 exports.inlined = inlined;
 exports.wrapSomethingAsync = wrapSomethingAsync;
 exports.wrapSomethingAsync2 = wrapSomethingAsync2;
 exports.M = M;
 exports.broken = broken$2;
+exports.nested1 = nested1;
+exports.nested2 = nested2;
 /* inlined Not a pure module */

jscomp/test/async_inline.res

@@ -36,3 +36,7 @@ let broken = async (someAsyncFunction) => {
 }
 
 let broken = someAsyncFunction => broken(someAsyncFunction)
+
+let nested1 = () => async (y) => await y
+
+let nested2 = async () => async (y) => await y

lib/4.06.1/unstable/js_compiler.ml

@@ -283499,6 +283499,8 @@ let rec cut n l =
 
 let try_ids = Hashtbl.create 8
 
+let has_async_attribute exp = exp.exp_attributes |> List.exists (fun ({txt}, _payload) -> txt = "res.async")
+
 let rec transl_exp e =
   List.iter (Translattribute.check_attribute e) e.exp_attributes;
   transl_exp0 e
@@ -283513,7 +283515,7 @@ and transl_exp0 (e : Typedtree.expression) : Lambda.lambda =
   | Texp_let (rec_flag, pat_expr_list, body) ->
       transl_let rec_flag pat_expr_list (transl_exp body)
   | Texp_function { arg_label = _; param; cases; partial } ->
-      let async = e.exp_attributes |> List.exists (fun ({txt}, _payload) -> txt = "res.async") in
+      let async = has_async_attribute e in
       let params, body, return_unit =
         let pl = push_defaults e.exp_loc [] cases partial in
         transl_function e.exp_loc partial param pl
@@ -283839,7 +283841,7 @@ and transl_function loc partial param cases =
        } as exp;
    };
   ]
-    when Parmatch.inactive ~partial pat ->
+    when Parmatch.inactive ~partial pat && not (exp |> has_async_attribute) ->
       let params, body, return_unit =
         transl_function exp.exp_loc partial' param' cases
       in

lib/4.06.1/unstable/js_playground_compiler.ml

@@ -293507,6 +293507,8 @@ let rec cut n l =
 
 let try_ids = Hashtbl.create 8
 
+let has_async_attribute exp = exp.exp_attributes |> List.exists (fun ({txt}, _payload) -> txt = "res.async")
+
 let rec transl_exp e =
   List.iter (Translattribute.check_attribute e) e.exp_attributes;
   transl_exp0 e
@@ -293521,7 +293523,7 @@ and transl_exp0 (e : Typedtree.expression) : Lambda.lambda =
   | Texp_let (rec_flag, pat_expr_list, body) ->
       transl_let rec_flag pat_expr_list (transl_exp body)
   | Texp_function { arg_label = _; param; cases; partial } ->
-      let async = e.exp_attributes |> List.exists (fun ({txt}, _payload) -> txt = "res.async") in
+      let async = has_async_attribute e in
       let params, body, return_unit =
         let pl = push_defaults e.exp_loc [] cases partial in
         transl_function e.exp_loc partial param pl
@@ -293847,7 +293849,7 @@ and transl_function loc partial param cases =
        } as exp;
    };
   ]
-    when Parmatch.inactive ~partial pat ->
+    when Parmatch.inactive ~partial pat && not (exp |> has_async_attribute) ->
       let params, body, return_unit =
         transl_function exp.exp_loc partial' param' cases
       in

lib/4.06.1/whole_compiler.ml

@@ -292966,6 +292966,8 @@ let rec cut n l =
 
 let try_ids = Hashtbl.create 8
 
+let has_async_attribute exp = exp.exp_attributes |> List.exists (fun ({txt}, _payload) -> txt = "res.async")
+
 let rec transl_exp e =
   List.iter (Translattribute.check_attribute e) e.exp_attributes;
   transl_exp0 e
@@ -292980,7 +292982,7 @@ and transl_exp0 (e : Typedtree.expression) : Lambda.lambda =
   | Texp_let (rec_flag, pat_expr_list, body) ->
       transl_let rec_flag pat_expr_list (transl_exp body)
   | Texp_function { arg_label = _; param; cases; partial } ->
-      let async = e.exp_attributes |> List.exists (fun ({txt}, _payload) -> txt = "res.async") in
+      let async = has_async_attribute e in
       let params, body, return_unit =
         let pl = push_defaults e.exp_loc [] cases partial in
         transl_function e.exp_loc partial param pl
@@ -293306,7 +293308,7 @@ and transl_function loc partial param cases =
        } as exp;
    };
   ]
-    when Parmatch.inactive ~partial pat ->
+    when Parmatch.inactive ~partial pat && not (exp |> has_async_attribute) ->
       let params, body, return_unit =
         transl_function exp.exp_loc partial' param' cases
       in