diff --git a/src/spell.c b/src/spell.c
index 039dfca..4807fff 100644
--- a/src/spell.c
+++ b/src/spell.c
@@ -4950,7 +4950,7 @@
 static void put_sugtime __ARGS((spellinfo_T *spin, FILE *fd));
 static int write_vim_spell __ARGS((spellinfo_T *spin, char_u *fname));
 static void clear_node __ARGS((wordnode_T *node));
-static int put_node __ARGS((FILE *fd, wordnode_T *node, int index, int regionmask, int prefixtree));
+static int put_node __ARGS((FILE *fd, wordnode_T *node, int idx, int regionmask, int prefixtree));
 static void spell_make_sugfile __ARGS((spellinfo_T *spin, char_u *wfname));
 static int sug_filltree __ARGS((spellinfo_T *spin, slang_T *slang));
 static int sug_maketable __ARGS((spellinfo_T *spin));