unused local definition for concrete values

[jamesward]

If I turn these on:

scalacOptions := Seq(
  "-Wunused:locals",
  "-Xfatal-warnings",
)

And have a defer that returns a concrete value like:

    defer:
      ZIO.debug("hello, world").run
      ()

I get:

[error] 6 |    defer:
[error]   |    ^
[error]   |    unused local definition

Reproducer: https://github.com/jamesward/zio-direct-bug-unused