| warning: ATTENTION! | |
| This build uses unsafe internal compiler arguments: | |
| -XXLanguage:-SealedInterfaces | |
| This mode is not recommended for production use, | |
| as no stability/compatibility guarantees are given on | |
| compiler or generated code. Use it at your own risk! | |
| compiler/testData/cli/jvm/languageVersion.kt:3:1: error: the feature "sealed interfaces" is disabled | |
| sealed interface Polygon | |
| ^ | |
| COMPILATION_ERROR |