- Using a `java.io.File` as the `@InputArtifact` of an artifact transform.
- Using an input with an unknown implementation.
See <<validation_problems.adoc#implementation_unknown,Cannot use an input with an unknown implementation>>.
- Missing dependencies between tasks.
See <<validation_problems.adoc#implicit_dependency,Implicit dependencies between tasks>>.
- Converting files to a classpath where paths contain file separator.