Fix issue with printing async functions with locally abstract types

CHANGELOG.md

@@ -58,6 +58,7 @@
 - Fix an issue where error messages related to duplicate props were displayed without a loc and were unclear https://github.com/rescript-lang/syntax/pull/728
 - 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 printing async functions with locally abstract types https://github.com/rescript-lang/syntax/pull/732
 
 #### :eyeglasses: Spec Compliance
 

src/res_parsetree_viewer.ml

@@ -163,10 +163,8 @@ let funExpr expr =
     | expr -> (attrsBefore, List.rev acc, expr)
   in
   match expr with
-  | {
-      pexp_desc = Pexp_fun (_, _defaultExpr, _pattern, _returnExpr);
-      pexp_attributes = attrs;
-    } as expr ->
+  | {pexp_desc = Pexp_fun _ | Pexp_newtype _; pexp_attributes = attrs} as expr
+    ->
     collect attrs [] {expr with pexp_attributes = []}
   | expr -> collect [] [] expr
 

tests/printer/expr/asyncAwait.res

@@ -116,4 +116,9 @@ let b4 = await (foo.bar.baz)
 
 let c1 = @foo x => @bar y => x + y
 let c2 = (. x) => y => x+y
-let c3 = (. x) => @foo y => x+y
+let c3 = (. x) => @foo y => x+y
+
+let f = async (type a, ()) => {
+   await Js.Promise.resolve(())
+ }
+

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

@@ -139,3 +139,7 @@ let b4 = await foo.bar.baz
 let c1 = @foo x => @bar y => x + y
 let c2 = (. x, y) => x + y
 let c3 = (. x) => @foo y => x + y
+
+let f = async (type a, ()) => {
+  await Js.Promise.resolve()
+}

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

@@ -1,19 +1,13 @@
 let f = (type t, xs: list<t>) => ()
-let f = (@attr type t, xs: list<t>) => ()
+let f = @attr (type t, xs: list<t>) => ()
 let f = (type t, xs: list<t>, type s, ys: list<s>) => ()
-let f = (@attr type t, xs: list<t>, @attr2 type s, ys: list<s>) => ()
+let f = @attr (type t, xs: list<t>, @attr2 type s, ys: list<s>) => ()
 let f = (type t u v, xs: list<(t, u, v)>) => ()
-let f = (@attr type t u v, xs: list<(t, u, v)>) => ()
+let f = @attr (type t u v, xs: list<(t, u, v)>) => ()
 let f = (type t u v, xs: list<(t, u, v)>, type s w z, ys: list<(s, w, z)>) => ()
-let f = (@attr type t u v, xs: list<(t, u, v)>, @attr2 type s w z, ys: list<(s, w, z)>) => ()
-let f = (
-  @attr type t,
-  @attr type s,
-  xs: list<(t, s)>,
-  @attr type u,
-  @attr type v w,
-  ys: list<(u, v, w)>,
-) => ()
+let f = @attr (type t u v, xs: list<(t, u, v)>, @attr2 type s w z, ys: list<(s, w, z)>) => ()
+let f = @attr
+(type t, @attr type s, xs: list<(t, s)>, @attr type u, @attr type v w, ys: list<(u, v, w)>) => ()
 
 let mk_formatting_gen:
   type a b c d e f. formatting_gen<a, b, c, d, e, f> => Parsetree.expression =