refactor: clarify uppercase exotic ident path

Author: cometkim

jscomp/syntax/src/res_printer.ml

@@ -376,7 +376,7 @@ let printLongident = function
   | Longident.Lident txt -> Doc.text txt
   | lid -> Doc.join ~sep:Doc.dot (printLongidentAux [] lid)
 
-type identifierStyle = ExoticIdent | NormalIdent
+type identifierStyle = UppercaseExoticIdent | ExoticIdent | NormalIdent
 
 let classifyIdentContent ?(allowUident = false) ?(allowHyphen = false) txt =
   if Token.isKeywordTxt txt then ExoticIdent
@@ -386,9 +386,9 @@ let classifyIdentContent ?(allowUident = false) ?(allowHyphen = false) txt =
       if i == len then NormalIdent
       else if i == 0 then
         match String.unsafe_get txt i with
+        | '\\' -> UppercaseExoticIdent
         | 'A' .. 'Z' when allowUident -> loop (i + 1)
         | 'a' .. 'z' | '_' -> loop (i + 1)
-        | '-' when allowHyphen -> loop (i + 1)
         | _ -> ExoticIdent
       else
         match String.unsafe_get txt i with
@@ -402,7 +402,7 @@ let printIdentLike ?allowUident ?allowHyphen txt =
   let txt = Ext_ident.unwrap_uppercase_exotic txt in
   match classifyIdentContent ?allowUident ?allowHyphen txt with
   | ExoticIdent -> Doc.concat [Doc.text "\\\""; Doc.text txt; Doc.text "\""]
-  | NormalIdent -> Doc.text txt
+  | UppercaseExoticIdent | NormalIdent -> Doc.text txt
 
 let rec unsafe_for_all_range s ~start ~finish p =
   start > finish
@@ -433,8 +433,14 @@ let printPolyVarIdent txt =
   (* numeric poly-vars don't need quotes: #644 *)
   if isValidNumericPolyvarNumber txt then Doc.text txt
   else
-    let txt = Ext_ident.unwrap_uppercase_exotic txt in
     match classifyIdentContent ~allowUident:true txt with
+    | UppercaseExoticIdent ->
+      Doc.concat
+        [
+          Doc.text "\"";
+          Doc.text (Ext_ident.unwrap_uppercase_exotic txt);
+          Doc.text "\"";
+        ]
     | ExoticIdent -> Doc.concat [Doc.text "\""; Doc.text txt; Doc.text "\""]
     | NormalIdent -> (
       match txt with