Fix printing of record types with optional labels

Fixes #583

Author: cristianoc

CHANGELOG.md

@@ -16,7 +16,11 @@
 
 - Add support for prop completion for JSX V4 https://github.com/rescript-lang/rescript-vscode/pull/579
 - Add support for create interface file for JSX V4 https://github.com/rescript-lang/rescript-vscode/pull/580
-- Expand one level of type definition on hover. Dig into record/variant body.
+- Expand one level of type definition on hover. Dig into record/variant body. https://github.com/rescript-lang/rescript-vscode/pull/584
+
+#### :bug: Bug Fix
+
+- Fix printing of record types with optional labels. https://github.com/rescript-lang/rescript-vscode/pull/584
 
 ## v1.6.0
 

analysis/tests/src/expected/Hover.res.txt

@@ -159,5 +159,5 @@ Completable: Cpath Value[y2].content.""
   }]
 
 Hover src/Hover.res 197:4
-{"contents": "```rescript\nCompV4.props<int, string> => React.element\n```\n\n```rescript\ntype props<'n, 's> = {n: option<'n>, s: 's}\n```\n\n```rescript\ntype element\n```"}
+{"contents": "```rescript\nCompV4.props<int, string> => React.element\n```\n\n```rescript\ntype props<'n, 's> = {?n: 'n, s: 's}\n```\n\n```rescript\ntype element\n```"}
 

analysis/vendor/compiler-libs-406/printtyp.ml

@@ -926,7 +926,7 @@ and tree_of_constructor cd =
       (name, args, Some ret)
 
 and tree_of_label l =
-  let opt = l.ld_attributes |> List.exists (fun ({txt}, _) -> txt = "optional") in
+  let opt = l.ld_attributes |> List.exists (fun ({txt}, _) -> txt = "ns.optional") in
   let typ = match l.ld_type.desc with
     | Tconstr (p, [t1], _) when opt && Path.same p Predef.path_option -> t1
     | _ -> l.ld_type in