diff --git a/src/beval.c b/src/beval.c
index c5fa220..d51a3f5 100644
--- a/src/beval.c
+++ b/src/beval.c
@@ -127,6 +127,8 @@
 #ifdef FEAT_VARTABS
 		vim_free(beval->vts);
 		beval->vts = tabstop_copy(wp->w_buffer->b_p_vts_array);
+		if (wp->w_buffer->b_p_vts_array != NULL && beval->vts == NULL)
+		    return FAIL;
 #endif
 		beval->ts = wp->w_buffer->b_p_ts;
 		return OK;