Per the docs, the default location is: src/main/resources.
My XSD's are in src/main/schema, so I need to change the sources setting.
So I have used the following:
sources in (xjc, Compile) <+= sourceDirectory / "main" / "schema"
This results in:
overloaded method value in with alternatives:
[error] (p: sbt.Reference,t: sbt.Scoped)sbt.ScopedTask[Seq[java.io.File]] <and>
[error] (p: sbt.Reference,c: sbt.ConfigKey)sbt.ScopedTask[Seq[java.io.File]] <and>
[error] (c: sbt.ConfigKey,t: sbt.Scoped)sbt.ScopedTask[Seq[java.io.File]]
[error] cannot be applied to (sbt.TaskKey[Seq[java.io.File]], sbt.Configuration)
[error] Error occurred in an application involving default arguments.
[error] sources in (xjc, Compile) <+= sourceDirectory / "main" / "schema"
[error] ^
[error] one error found