diff --git a/src/parser/treeify.rs b/src/parser/treeify.rs
index 535f220..f9e3a91 100644
--- a/src/parser/treeify.rs
+++ b/src/parser/treeify.rs
@@ -6,7 +6,7 @@ use crate::parser::ParserError;
 use crate::parser::Operator;
 
 fn treeify_binary(
-	mut i: usize,
+	i: usize,
 	g_inner: &mut VecDeque<Token>,
 	left_associative: bool
 ) -> Result<(), (LineLocation, ParserError)> {