Annotation type-safety

The library introduces a concept of annotation type-safety. Consider the following example:

        @Rpc
        interface MyService

        class MyServiceImpl : MyService

        fun <T> withService() {}

The compiler can't guarantee that the passed type parameter is the one for which the code generation was run:

        withService<MyService>() // ok
        withService<MyServiceImpl>() // compile time ok, runtime throws
    

The compiler plugin enforces annotation type-safety by requiring type parameters to have specific annotations, like @Rpc.

        @Rpc
        interface MyService

        class MyServiceImpl : MyService

        fun <@Rpc T : Any> withService() {}

        withService<MyService>() // ok
        withService<MyServiceImpl>() // compile time error
    

Annotation type-safety can be enforced recursively:

        @Rpc
        annotation class Grpc

        @Grpc
        interface MyGrpcService

        fun <@Rpc T> acceptAnyRpcType()
        fun <@Grpc T> acceptOnlyGrpcType()

        acceptAnyRpcType<MyService>() // OK
        acceptAnyRpcType<MyGrpcService>() // OK

        acceptOnlyGrpcType<MyService>() // Compiler time error
        acceptOnlyGrpcType<MyGrpcService>() // OK
    

Last modified: 25 June 2025