I’ve got the following problem: here’s an interface called `Source`:

interface Source : Closeable {
  @Throws(IOException::class)
  fun read(sink: Buffer, byteCount: Long): Long
}

I’m declaring

SuspendingSource

like this:

interface SuspendingSource : Source {
  @Throws(IOException::class)
  override suspend fun read(sink: Buffer, byteCount: Long): Long
}

which doesn’t compile because of

Conflicting overloads

. Is it forbidden to override non-suspend functions with suspend ones?

Yes, it is forbidden. Since the anyone calling

Source.read

doesn't not know to suspend.

Ah, makes sense

It’s also quite intuitive if you look at the generated bytecode of a suspend function. They work by passing a hidden extra argument which tells the function where to resume.