${.} in defaults seems not work as expected

[etclub]

The manual says ${.} will resolve to the directory containing the defaults file itself.
I have defaults.yaml and test.yaml in the same directory.
And in defaults.yaml, there is

defaults:
  - ${.}/test

But when I run pandoc -d defaults, it reports error

pandoc: ${.}/test.yaml: withBinaryFile: does not exist (No such file or directory)

[jgm]

This is issue #8024.