patch 7.4.699
Problem:    E315 when trying to delete a fold. (Yutao Yuan)
Solution:   Make sure the fold doesn't go beyond the last buffer line.
            (Christian Brabandt)
diff --git a/src/fold.c b/src/fold.c
index 41fcee0..671bbf7 100644
--- a/src/fold.c
+++ b/src/fold.c
@@ -234,6 +234,8 @@
 	return FALSE;
     }
 
+    if (last > win->w_buffer->b_ml.ml_line_count)
+	last = win->w_buffer->b_ml.ml_line_count;
     if (lastp != NULL)
 	*lastp = last;
     if (firstp != NULL)