1 files changed, 1 insertions, 1 deletions

diff --git a/lapi.c b/lapi.c
index 27bf23da..41e6b86d 100644
--- a/lapi.c
+++ b/lapi.c
@@ -39,7 +39,7 @@ const char lua_ident[] =
 
 
 /*
-** Test for a valid index.
+** Test for a valid index (one that is not the 'nilvalue').
 ** '!ttisnil(o)' implies 'o != &G(L)->nilvalue', so it is not needed.
 ** However, it covers the most common cases in a faster way.
 */