From f8026a0852af4230ad5d807a3ad6894736455782 Mon Sep 17 00:00:00 2001
From: Hyeseong Kim <hey@hyeseong.kim>
Date: Sun, 26 May 2024 08:31:52 +0900
Subject: [PATCH 1/3] refactor: clarify uppercase exotic ident path

---
 jscomp/syntax/src/res_printer.ml | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/jscomp/syntax/src/res_printer.ml b/jscomp/syntax/src/res_printer.ml
index f9d370af46..bc6823456f 100644
--- a/jscomp/syntax/src/res_printer.ml
+++ b/jscomp/syntax/src/res_printer.ml
@@ -378,7 +378,7 @@ let print_longident = function
   | Longident.Lident txt -> Doc.text txt
   | lid -> Doc.join ~sep:Doc.dot (print_longident_aux [] lid)
 
-type identifier_style = ExoticIdent | NormalIdent
+type identifier_style = UppercaseExoticIdent | ExoticIdent | NormalIdent
 
 let classify_ident_content ?(allow_uident = false) ?(allow_hyphen = false) txt =
   if Token.is_keyword_txt txt then ExoticIdent
@@ -388,9 +388,9 @@ let classify_ident_content ?(allow_uident = false) ?(allow_hyphen = false) txt =
       if i == len then NormalIdent
       else if i == 0 then
         match String.unsafe_get txt i with
+        | '\\' -> UppercaseExoticIdent
         | 'A' .. 'Z' when allow_uident -> loop (i + 1)
         | 'a' .. 'z' | '_' -> loop (i + 1)
-        | '-' when allow_hyphen -> loop (i + 1)
         | _ -> ExoticIdent
       else
         match String.unsafe_get txt i with
@@ -404,7 +404,7 @@ let print_ident_like ?allow_uident ?allow_hyphen txt =
   let txt = Ext_ident.unwrap_uppercase_exotic txt in
   match classify_ident_content ?allow_uident ?allow_hyphen 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
@@ -435,8 +435,14 @@ let print_poly_var_ident txt =
   (* numeric poly-vars don't need quotes: #644 *)
   if is_valid_numeric_polyvar_number txt then Doc.text txt
   else
-    let txt = Ext_ident.unwrap_uppercase_exotic txt in
     match classify_ident_content ~allow_uident: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

From 842fcad6d9ab2b12577779fc4adc755867177702 Mon Sep 17 00:00:00 2001
From: Hyeseong Kim <hey@hyeseong.kim>
Date: Sun, 26 May 2024 22:30:13 +0900
Subject: [PATCH 2/3] remove unnecessary unwrap

---
 jscomp/syntax/src/res_printer.ml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/jscomp/syntax/src/res_printer.ml b/jscomp/syntax/src/res_printer.ml
index bc6823456f..86b9bf51c4 100644
--- a/jscomp/syntax/src/res_printer.ml
+++ b/jscomp/syntax/src/res_printer.ml
@@ -401,7 +401,6 @@ let classify_ident_content ?(allow_uident = false) ?(allow_hyphen = false) txt =
     loop 0
 
 let print_ident_like ?allow_uident ?allow_hyphen txt =
-  let txt = Ext_ident.unwrap_uppercase_exotic txt in
   match classify_ident_content ?allow_uident ?allow_hyphen txt with
   | ExoticIdent -> Doc.concat [Doc.text "\\\""; Doc.text txt; Doc.text "\""]
   | UppercaseExoticIdent | NormalIdent -> Doc.text txt

From b0c6f1e70d544e235e611f11078e76ba8428ee26 Mon Sep 17 00:00:00 2001
From: Hyeseong Kim <hey@hyeseong.kim>
Date: Mon, 27 May 2024 17:34:08 +0900
Subject: [PATCH 3/3] use `String.sub` intead of `unwrap_uppercase_exotic`

---
 jscomp/syntax/src/res_printer.ml | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/jscomp/syntax/src/res_printer.ml b/jscomp/syntax/src/res_printer.ml
index 86b9bf51c4..109a053bca 100644
--- a/jscomp/syntax/src/res_printer.ml
+++ b/jscomp/syntax/src/res_printer.ml
@@ -436,12 +436,10 @@ let print_poly_var_ident txt =
   else
     match classify_ident_content ~allow_uident:true txt with
     | UppercaseExoticIdent ->
-      Doc.concat
-        [
-          Doc.text "\"";
-          Doc.text (Ext_ident.unwrap_uppercase_exotic txt);
-          Doc.text "\"";
-        ]
+      let len = String.length txt in
+      (* UppercaseExoticIdent follows the \"..." format,
+         so removing the leading backslash is enough to transform it into polyvar style *)
+      Doc.text ((String.sub [@doesNotRaise]) txt 1 (len - 1))
     | ExoticIdent -> Doc.concat [Doc.text "\""; Doc.text txt; Doc.text "\""]
     | NormalIdent -> (
       match txt with