diff --git a/src/include/strings.h b/src/include/strings.h
index 9e8663597..9ef03d33e 100755
--- a/src/include/strings.h
+++ b/src/include/strings.h
@@ -77,7 +77,6 @@ public:
   // @cmember Ritorna un riferimento al carattere i-esimo della stringa
   char& operator[](int i)
   { 
-    CHECKD(i >= 0 && i <= _size, "Bad string subscript: ", i);
     CHECKD(i >= 0 && i <= _size, "Bad string subscript: ", i);
     return _str[i]; 
   }