diff --git a/src/eval.c b/src/eval.c
index 2a2d9d4..6e88c5c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -5682,6 +5682,7 @@
 {
     if (varp->v_type == VAR_LIST
 	    || varp->v_type == VAR_DICT
+	    || varp->v_type == VAR_BLOB
 	    || varp->v_type == VAR_FUNC
 	    || varp->v_type == VAR_PARTIAL
 	    || varp->v_type == VAR_FLOAT)
@@ -6057,6 +6058,12 @@
 		p = tv_get_string_buf(&rettv, buf);
 	    else
 		p = tv_stringify(&rettv, buf);
+	    if (p == NULL)
+	    {
+		clear_tv(&rettv);
+		ret = FAIL;
+		break;
+	    }
 	    len = (int)STRLEN(p);
 	    if (ga_grow(&ga, len + 2) == FAIL)
 	    {