fix: prevent stripping of quotes for empty polymorphic variant (#474)

Author: a-c-sreedhar-reddy

src/res_printer.ml

@@ -459,7 +459,13 @@ let printPolyVarIdent txt =
         Doc.text txt;
         Doc.text"\""
       ]
-    | NormalIdent -> Doc.text txt
+    | NormalIdent -> match txt with
+      | "" -> Doc.concat [
+        Doc.text "\"";
+        Doc.text txt;
+        Doc.text"\""
+      ]
+      | _ -> Doc.text txt
 
 
 let printLident l = match l with

tests/printer/pattern/expected/variant.res.txt

@@ -43,3 +43,5 @@ switch numericPolyVar {
 | #42 => ()
 | #3(x, y, z) => Js.log3(x, y, z)
 }
+
+let e = #""

tests/printer/pattern/variant.res

@@ -43,3 +43,5 @@ switch numericPolyVar {
 | #42 => ()
 | #3(x, y, z) => Js.log3(x, y, z)
 }
+
+let e = #""