diff --git a/src/fold.c b/src/fold.c
index 8f068dc..f8abe22 100644
--- a/src/fold.c
+++ b/src/fold.c
@@ -2928,7 +2928,7 @@
 	{
 	    /* 2: or 3: need to delete nested folds */
 	    foldRemove(&fp->fd_nested, top - fp->fd_top, bot - fp->fd_top);
-	    if (fp->fd_top + fp->fd_len > bot + 1)
+	    if (fp->fd_top + fp->fd_len - 1 > bot)
 	    {
 		/* 3: need to split it. */
 		foldSplit(gap, (int)(fp - (fold_T *)gap->ga_data), top, bot);
@@ -2970,10 +2970,12 @@
 
 /* foldReverseOrder() {{{2 */
     static void
-foldReverseOrder(garray_T *gap, linenr_T start, linenr_T end)
+foldReverseOrder(garray_T *gap, linenr_T start_arg, linenr_T end_arg)
 {
     fold_T *left, *right;
     fold_T tmp;
+    linenr_T start = start_arg;
+    linenr_T end = end_arg;
 
     for (; start < end; start++, end--)
     {
diff --git a/src/version.c b/src/version.c
index 0533f57..fd84c76 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    583,
+/**/
     582,
 /**/
     581,