[Enhancment] Calling `expectSelfie()` from another package

Start by reproducing the cross-package ErrorSpec example and inspect SelfieImplementations/DiskSelfie.toMatchDisk(), especially the behavior around line 38 and CallLocation source lookup. Compare it with toMatchDisk_TODO(). Done means the public API can validate and write snapshots from another package without relying on TODO behavior or overwriting them on every run.

Hello, the library is pretty useful, but I'm stumbling into a problem that I'm not sure how to fix.

Using Kotest, I want to create a reusable Spec to snapshot tests my custom exceptions and their localization.
It ends up looking kind of like this:

package mypackage.errors

abstract class ErrorSpec<T : Error>(
    private val clazz: KClass<T>,
    private val create: () -> T
) :
    FunSpec({
        context("Localisation") {
            forAll(Exhaustive.collection(SUPPORTED_LOCALES)) {

                expectSelfie(json.encodeToString(clazz.serializer(), create())).toMatchDisk()

            }
        }
    })

class ErrorTest : ErrorSpec<Error>(
    clazz = Error::class,
    create = { Error() }
)

This work perfectly, until I put ErrorSpec in another package.
The main reason I want to do this is to use a testFixtures.

This then ends up failing at runtime with:

org.opentest4j.AssertionFailedError:
Couldn't find source file for CallLocation(
    clazz=mypackage.ErrorSpec$1$1,
    method=invokeSuspend,
    fileName=Specs.kt,
    line=36
),

looked in TypedPath(absolutePath=[...]/mypackage/src/test/kotlin/)
and [[...]/mypackage/src/test/resources],

maybe there are other source roots?

What I don't understand is that, if I use toMatchDisk_TODO() instead of toMatchDisk(), the snapshot files end up being written, but the tests fails on writeLine.

Manually changing the value of isTodo to true in SelfieImplementations/DiskSelfie.toMatchDisk():38, the tests pass successfully, with the snapshot file being written at the correct place (albeit being overwritten every run, which kind of defeat the point).

Is there a way to do what I want using the public API?
If not, would it be possible to implement?