KT element: KtNamedFunction
FIR element: FirSimpleFunctionImpl
FIR source kind: KtRealSourceElementKind

FIR element rendered:
public final [ResolvedTo(BODY_RESOLVE)] fun <[ResolvedTo(BODY_RESOLVE)] T> R|kotlin/Array<out kotlin/Array<out T>>|.flatten(): R|kotlin/collections/List<T>|