From fc32d4e8b9a8001e9cb80ce359f9a678341a930c Mon Sep 17 00:00:00 2001
From: Cheng Lou <chenglou92@gmail.com>
Date: Mon, 23 Oct 2017 22:57:14 -0700
Subject: [PATCH] Enhance #1539

---
 .../expected_output/mlSyntax.re               |  8 ++++
 .../expected_output/mlSyntax.re.4.02.3        |  8 ++++
 formatTest/typeCheckedTests/input/mlSyntax.ml |  6 ++-
 src/syntax_util.ml                            | 38 ++++++++++++++++---
 4 files changed, 52 insertions(+), 8 deletions(-)

diff --git a/formatTest/typeCheckedTests/expected_output/mlSyntax.re b/formatTest/typeCheckedTests/expected_output/mlSyntax.re
index 68c98e7a2..c397634f7 100644
--- a/formatTest/typeCheckedTests/expected_output/mlSyntax.re
+++ b/formatTest/typeCheckedTests/expected_output/mlSyntax.re
@@ -100,8 +100,16 @@ module EM = {
 
 exception Ealias = EM.E;
 
+let switc = "match";
+
 let switch_ = "match";
 
+let switch__ = "match";
+
 let pub_ = "method";
 
+let pub__ = "method";
+
 let pri_ = "private";
+
+let pri__ = "private";
diff --git a/formatTest/typeCheckedTests/expected_output/mlSyntax.re.4.02.3 b/formatTest/typeCheckedTests/expected_output/mlSyntax.re.4.02.3
index f7e37aae7..07a607b06 100644
--- a/formatTest/typeCheckedTests/expected_output/mlSyntax.re.4.02.3
+++ b/formatTest/typeCheckedTests/expected_output/mlSyntax.re.4.02.3
@@ -100,8 +100,16 @@ module EM = {
 
 exception Ealias = EM.E;
 
+let switc = "match";
+
 let switch_ = "match";
 
+let switch__ = "match";
+
 let pub_ = "method";
 
+let pub__ = "method";
+
 let pri_ = "private";
+
+let pri__ = "private";
diff --git a/formatTest/typeCheckedTests/input/mlSyntax.ml b/formatTest/typeCheckedTests/input/mlSyntax.ml
index 208b26a96..3ff254e9f 100644
--- a/formatTest/typeCheckedTests/input/mlSyntax.ml
+++ b/formatTest/typeCheckedTests/input/mlSyntax.ml
@@ -70,8 +70,10 @@ end
 
 exception Ealias = EM.E
 
+let switc = "match"
 let switch = "match"
-
+let switch_ = "match"
 let pub = "method"
-
+let pub_ = "method"
 let pri = "private"
+let pri_ = "private"
diff --git a/src/syntax_util.ml b/src/syntax_util.ml
index 268dbbb0e..efc8ee107 100644
--- a/src/syntax_util.ml
+++ b/src/syntax_util.ml
@@ -168,10 +168,36 @@ let string_drop_suffix x = String.sub x 0 (String.length x - 1)
     and ocaml syntax, ocaml `not` converts to `!`, reason `!` converts to
     `not`.
 
-    In more complicated cases where a keyword exists in one syntax but not the
-    other these functions translate any potentially conflicting identifier into
-    the same identifier with a suffix attached, or remove the suffix when
-    converting back.
+    In more complicated cases where a reserved keyword exists in one syntax but
+    not the other, these functions translate any potentially conflicting
+    identifier into the same identifier with a suffix attached, or remove the
+    suffix when converting back. Two examples:
+
+    reason to ocaml:
+
+    pub: invalid in reason to begin with
+    pub_: pub
+    pub__: pub_
+
+    ocaml to reason:
+
+    pub: pub_
+    pub_: pub__
+    pub__: pub___
+
+    =====
+
+    reason to ocaml:
+
+    match: match_
+    match_: match__
+    match__: match___
+
+    ocaml to reason:
+
+    match: invalid in ocaml to begin with
+    match_: match
+    match__: match_
 *)
 
 let reason_to_ml_swap = function
@@ -259,8 +285,8 @@ let identifier_mapper f super =
     in
     super.pat mapper pat
   end;
-  signature_item = begin fun mapper signatureItem -> 
-    let signatureItem = 
+  signature_item = begin fun mapper signatureItem ->
+    let signatureItem =
       match signatureItem with
         | {psig_desc=Psig_value ({pval_name} as name);
            psig_loc} ->