/test.kt:(152,157): warning: Argument type mismatch: actual type is 'kotlin.String?', but 'kotlin.String' was expected. This will become an error in a future release.

/test.kt:(240,245): warning: Argument type mismatch: actual type is 'kotlin.String?', but 'kotlin.String' was expected. This will become an error in a future release.

/test.kt:(240,245): error: Return type mismatch: expected 'kotlin.String', actual 'kotlin.String?'.

/test.kt:(240,245): error: Argument type mismatch: actual type is 'kotlin.String?', but 'kotlin.String' was expected.

/test.kt:(361,366): warning: Argument type mismatch: actual type is 'kotlin.String?', but 'kotlin.String' was expected. This will become an error in a future release.

/test.kt:(463,468): warning: Argument type mismatch: actual type is 'kotlin.String?', but 'kotlin.String' was expected. This will become an error in a future release.

/test.kt:(499,504): warning: Argument type mismatch: actual type is 'kotlin.String?', but 'kotlin.String' was expected. This will become an error in a future release.

/test.kt:(559,564): warning: Argument type mismatch: actual type is 'kotlin.String?', but 'kotlin.String' was expected. This will become an error in a future release.

/test.kt:(824,831): error: Return type of 'get' is not a subtype of the return type of the overridden member 'fun get(): String'.

/test.kt:(900,903): error: Return type of 'get' is not a subtype of the return type of the overridden member 'fun get(): String'.
