(trying to adapt https://stackoverflow.com/questions/36253310/how-to-get-actual-type-arguments-of-a-reified-generic-parameter-in-kotlin to get a

KType

rather than a

Type

)

Do you mean this one? https://gist.github.com/udalov/bb6f398c2e643ee69586356fdd67e9b1 It somehow works for me. The

ERROR

type I only get if I don’t create an anonymous subclass at the call site (i.e. in the

inline fun getKType

). I noticed however that the resulting

KType

(and

KTypeProjection

) has various issues: • You cannot get the

KClass

or

Class

which was used to create the

KType

so you have to store that info separately. • The

KType

lacks nullability information. • The

KTypeProjection

doesn’t have star projection anymore (turns into

out UpperBound?

at runtime). •

KType

itself isn’t generic and thus you lose compile-time safety when passing around `KType`s instead of `KClass`es. • I think `KType`’s implementation isn’t optimized that much for performance.

isSubtypeOf

for example looks scary. •

KTypeProjection

lacks

isSubtypeOf

or something similar to check whether two projections are compatible/assignable.

The

toString()

of the resulting

KType

always contains “ERROR: …” for me. I was particularly interested in the nullability information, but as you said, it’s not there. kotlin-reflect feels a bit shaky and doesn’t seem quite there yet. also got lots of errors when debugging it.

Unfortunately there cannot be nullability information when

KType

is constructed from Java’s

Type

since Java doesn’t have any info about nullability.

I didn’t construct

KType

from java’s

Type

, I constructed it using kotlin reflection. same thing.

How did you construct it?

KClass.createType

allows you to specify nullability 😮

lol

Ah, yeah. Regarding generic inheritance I think Kotlin has the same limitations as Java - i.e. type erasure 😕

this is using reified super type token, and works for

Class

. why can’t it work for

KClass

too?

Yeah that would be great but I think it isn’t 😞

I simply think it’s not mature, some things haven’t been implemented yet.