diff --git a/src/ocaml/preprocess/lexer_ident.mll b/src/ocaml/preprocess/lexer_ident.mll
index e9690dbd27..fd448d141c 100644
--- a/src/ocaml/preprocess/lexer_ident.mll
+++ b/src/ocaml/preprocess/lexer_ident.mll
@@ -91,6 +91,7 @@ rule token = parse
     { UIDENT ident }
   | "`"  { BACKQUOTE }
   | "'"  { QUOTE }
+  | "()" { LIDENT "()"}
   | "("  { LPAREN }
   | ")"  { RPAREN }
   | "."  { DOT }