Kotshi kapt fails to find @KotshiConstructor annotated constructor

[LouisCAD]

The compilation error strikes with this:

import se.ansman.kotshi.JsonSerializable
import se.ansman.kotshi.KotshiConstructor
import splitties.exceptions.unsupported

@JsonSerializable
@Suppress("DataClassPrivateConstructor")
data class FcmToken private constructor(val androidId: String, val token: String, val appId: Int) {
    constructor(androidId: String, token: String) : this(androidId, token, 857930)
    @Suppress("UNREACHABLE_CODE")
    @KotshiConstructor
    constructor() : this(unsupported(), unsupported())
}

In the snippet above, unsupported() returns Nothing, just like Kotlin's TODO(). The goal is to enforce the fact that this model is only for serialization, not parsing.

Here's the error:

:app:kaptGenerateStubsDebugProdApiKotlin
e: C:\Users\Me\AndroidStudioProjects\MyProject\app\build\tmp\kapt3\stubs\buildType\my\package\name\model\api\FcmToken.java:8: error: Kotshi: Multiple constructors found, please annotate the primary one with @KotshiConstructor
public final class FcmToken {
             ^
:app:kaptDebugProdApiKotlin FAILED

FAILURE: Build failed with an exception.

[ansman]

This is not supported at all, perhaps we it would be in the future by using annotation arguments.

[LouisCAD]

Tried to workaround this by adding a nothing: Nothing parameter, but it seems I can't really, because there's a mismatch between the constructor parameter names and the properties on the class.