diff --git a/package/test/parser.jl b/package/test/parser.jl
index 795b98a..6ec7684 100644
--- a/package/test/parser.jl
+++ b/package/test/parser.jl
@@ -192,7 +192,7 @@ function parse_factor!(p::Parser)
     end
 
     if sign == -1
-        neg_simpl(factor)
+        :(-$factor)
     else
         factor
     end