Fix parsing of poly-var typexpr consisting of one tag-spec-first (#254)

* Fix parsing of poly-var typexpr consisting of only tag-spec-first

`[s]` or `[ListStyleType.t]` should parse without more tag-spec's

* Add bs-css to roundtrip tests

* Add changelog entry

Author: IwanKaramazow

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## Unreleased
 
-* Implement new syntax for guards on pattern match cases in [3248](https://github.com/rescript-lang/syntax/pull/248)
+* Fix parsing of poly-var typexpr consisting of one tag-spec-first in [254](https://github.com/rescript-lang/syntax/pull/254)
+* Implement new syntax for guards on pattern match cases in [#248](https://github.com/rescript-lang/syntax/pull/248)
 * Implement intelligent breaking for poly-var type expressions in [#246](https://github.com/rescript-lang/syntax/pull/246)
 * Improve indentation of fast pipe chain in let binding in [#244](https://github.com/rescript-lang/syntax/pull/244)
 * Improve printing of non-callback arguments in call expressions with callback in [#241](https://github.com/rescript-lang/syntax/pull/241/files)

src/res_core.ml

@@ -4827,8 +4827,14 @@ and parseTagSpecFirst p =
     [parsePolymorphicVariantTypeSpecHash ~attrs ~full:false p]
   | _ ->
     let typ = parseTypExpr ~attrs p in
-    Parser.expect Bar p;
-    [Parsetree.Rinherit typ; parseTagSpec p]
+    begin match p.token with
+    | Rbracket ->
+      (* example: [ListStyleType.t] *)
+      [Parsetree.Rinherit typ;]
+    | _ ->
+      Parser.expect Bar p;
+      [Parsetree.Rinherit typ; parseTagSpec p]
+    end
 
 and parsePolymorphicVariantTypeSpecHash ~attrs ~full p : Parsetree.row_field =
   let startPos = p.Parser.startPos in

tests/idempotency/bs-css/Css.re

@@ -0,0 +1,16 @@
+include Css_Legacy_Core;
+include Css_Colors;
+
+include Css_Legacy_Core.Make({
+  exception NotImplemented;
+
+  let make = (. _) => raise(NotImplemented);
+  let mergeStyles = (. _) => raise(NotImplemented);
+  let injectRule = (. _) => ();
+  let injectRaw = (. _) => ();
+  let makeKeyFrames = (. _) => raise(NotImplemented);
+});
+
+external unsafeJsonToStyles: Js.Json.t => ReactDOMRe.Style.t = "%identity";
+
+let style = rules => rules->toJson->unsafeJsonToStyles;

tests/idempotency/bs-css/CssEmotion.re

@@ -0,0 +1,37 @@
+include Css_Legacy_Core;
+include Css_Colors;
+
+include Css_Legacy_Core.Make({
+  [@bs.module "emotion"]
+  external mergeStyles: (. array(string)) => string = "cx";
+
+  [@bs.module "emotion"] external make: (. Js.Json.t) => string = "css";
+
+  [@bs.module "emotion"]
+  external injectRule: (. Js.Json.t) => unit = "injectGlobal";
+
+  [@bs.module "emotion"]
+  external injectRaw: (. string) => unit = "injectGlobal";
+
+  [@bs.module "emotion"]
+  external makeKeyFrames: (. Js.Dict.t(Js.Json.t)) => string = "keyframes";
+});
+
+type cache;
+
+[@bs.module "emotion"] external cache: cache = "cache";
+
+let fontFace =
+    (~fontFamily, ~src, ~fontStyle=?, ~fontWeight=?, ~fontDisplay=?, ()) => {
+  let asString =
+    Css_Legacy_Core.fontFace(
+      ~fontFamily,
+      ~src,
+      ~fontStyle?,
+      ~fontWeight?,
+      ~fontDisplay?,
+      (),
+    );
+  insertRule(asString);
+  fontFamily;
+};

tests/idempotency/bs-css/CssEmotionJs.re

@@ -0,0 +1,37 @@
+include Css_Js_Core;
+include Css_Colors;
+
+include Css_Js_Core.Make({
+  [@bs.module "emotion"]
+  external mergeStyles: (. array(string)) => string = "cx";
+
+  [@bs.module "emotion"] external make: (. Js.Json.t) => string = "css";
+
+  [@bs.module "emotion"]
+  external injectRule: (. Js.Json.t) => unit = "injectGlobal";
+
+  [@bs.module "emotion"]
+  external injectRaw: (. string) => unit = "injectGlobal";
+
+  [@bs.module "emotion"]
+  external makeKeyFrames: (. Js.Dict.t(Js.Json.t)) => string = "keyframes";
+});
+
+type cache;
+
+[@bs.module "emotion"] external cache: cache = "cache";
+
+let fontFace =
+    (~fontFamily, ~src, ~fontStyle=?, ~fontWeight=?, ~fontDisplay=?, ()) => {
+  insertRule(.
+    Css_Js_Core.fontFace(
+      ~fontFamily,
+      ~src,
+      ~fontStyle?,
+      ~fontWeight?,
+      ~fontDisplay?,
+      (),
+    ),
+  );
+  fontFamily;
+};

tests/idempotency/bs-css/CssJs.re

@@ -0,0 +1,16 @@
+include Css_Js_Core;
+include Css_Colors;
+
+include Css_Js_Core.Make({
+  exception NotImplemented;
+
+  let make = (. _) => raise(NotImplemented);
+  let mergeStyles = (. _) => raise(NotImplemented);
+  let injectRule = (. _) => ();
+  let injectRaw = (. _) => ();
+  let makeKeyFrames = (. _) => raise(NotImplemented);
+});
+
+external unsafeJsonToStyles: Js.Json.t => ReactDOMRe.Style.t = "%identity";
+
+let style = (. rules) => rules->toJson->unsafeJsonToStyles;