`kotlinOptions.freeCompilerArgs += ["-Xprogressive"]`

# gradle

[ilya.gorbunov]

kotlinOptions.freeCompilerArgs += ["-Xprogressive"]

[gildor]

Maybe make sense to have proper Gradle DSL for existing compiler flags
After all Kotlin Gradle plugin has the same version as Kotlin compiler, so it shouldn't have any problem with compatibility and much better discoverability