Is it possible to tell Kotlin compiler to generate inner static classes out of object expressions?

Does it not do that? It does for me, also setting the enclosing class and enclosing method tags properly.

They are local which leads to an issue with jackson deserialization https://github.com/FasterXML/jackson-module-kotlin/issues/135

There is no object expression in the code posted there. There is a local class, hence

Class#isLocalClass

returns true. This is not Kotlin's "fault", the same would happen in Java.

when I do something like

fun foo(bar: Sting): Any {
  val obj = object : SomeClass() {
    val buz = bar
  }
  return obj;
}

Yes. Local means "inside a method".

So, I want the compiler to make it non-local

why not just move it out of the fun ?

But it is local... You want the compiler to generate wrong metadata...

Because this is less verbose when the object is defined in the method. And I don't have to invent a name for the class