diff --git a/src/etc/lexer.cpp b/src/etc/lexer.cpp
index f57e2ff..27a7261 100644
--- a/src/etc/lexer.cpp
+++ b/src/etc/lexer.cpp
@@ -26,7 +26,7 @@ vector<tok> lex(const string& in)
             [[likely]] case ' ': case '\t': case '\r': break;
             [[likely]] case '\n': ++lineNumber; break;
             default: {
-                tok::type type = getIdentifierCharType(current);
+                const tok::type type = getIdentifierCharType(current);
                 bool isTypeString = (type == STRING);
                 switch (type) {
                     case STRING: ++i;