Variable not referred in from clause

[czpmango]

(czp@nebula) [nba]> $var = GO FROM "Tim Duncan" OVER * yield like._dst as dst;go from "Tim Duncan" over like yield $var.dst

[ERROR (-1009)]: SemanticError: A variable must be referred in FROM before used in WHERE or YIELD

(czp@nebula) [nba]> $var=go from "Tim Duncan" over * yield like._dst as dst;$var1=go from $var.dst over like yield like._dst as dst1;go from $var1.dst1 over like yield $var.dst
+----------+
| $var.dst |
+----------+
| __NULL__ |
+----------+
| __NULL__ |
+----------+
| __NULL__ |
+----------+
| __NULL__ |
+----------+
| __NULL__ |
+----------+
| __NULL__ |
+----------+
| __NULL__ |
+----------+
Got 7 rows (time spent 23942/25187 us)

$var.dst never be referred in from clause of the third sequential sentence but used in yield clause.