diff --git a/src/Lexer.cpp b/src/Lexer.cpp
index 122878a..d1f30e3 100644
--- a/src/Lexer.cpp
+++ b/src/Lexer.cpp
@@ -23,7 +23,7 @@ int Lexer::advance()
     prev_loc = loc;
     ++index;
     loc.advance();
-    if(index == current_lexed_text.size()) return 0;
+    if(index >= current_lexed_text.size()) return 0;
     current_char = current_lexed_text[index];
     loc.pos_from_char(current_char);
     if(current_char == '\n')