sqlcl: Substitution Variable in Script Name Not Working

[ann--b]

Note: This works in sql plus.

From sqlcl:

sql> @dir1/script1.sql

script1.sql:
@@script2.sql

script2.sql:
define myVar = x
@@dir1/&myVar._y

SP2-0310: Unable to open file: "dir1/x.sql"