ConeNullability.NULLABLE -> KaTypeNullability.NULLABLE
    ConeNullability.UNKNOWN -> KaTypeNullability.UNKNOWN
    ConeNullability.NOT_NULL -> KaTypeNullability.NON_NULLABLE

public sealed class KaClassTypeBuilder : KaTypeBuilder() {
    private val backingArguments = mutableListOf<KaTypeProjection>()

    public var nullability: KaTypeNullability = KaTypeNullability.NON_NULLABLE
        get() = withValidityAssertion { field }
        set(value) {
            withValidityAssertion { field = value }
        }

public typealias KtType = KaType

public enum class KaTypeNullability(public val isNullable: Boolean) {
    NULLABLE(true),
    NON_NULLABLE(false),
    UNKNOWN(false);

    public companion object {
        public fun create(isNullable: Boolean): KaTypeNullability = if (isNullable) NULLABLE else NON_NULLABLE
    }
}

public typealias KtTypeNullability = KaTypeNullability

public interface KaErrorType : KaType {

                    lower is KaTypeParameterType && upper is KaTypeParameterType && lower.symbol == upper.symbol
            if (isTheSameType &&
                lower.nullability == KaTypeNullability.NON_NULLABLE
                && upper.nullability == KaTypeNullability.NULLABLE
            ) {
                if (lower !is KaNonErrorClassType && upper !is KaNonErrorClassType) {
                    return true
                }

        else -> this
    } ?: this
}

internal fun KaTypeNullability.toConeNullability() = when (this) {
    KaTypeNullability.NULLABLE -> ConeNullability.NULLABLE
    KaTypeNullability.NON_NULLABLE -> ConeNullability.NOT_NULL
    KaTypeNullability.UNKNOWN -> ConeNullability.UNKNOWN
}

/**
 * @receiver A symbol that needs to be imported
 * @param useSiteSession A use-site fir session.

    get() = when {
        this.isNullabilityFlexible() -> KaTypeNullability.UNKNOWN
        this.isMarkedNullable -> KaTypeNullability.NULLABLE
        else -> KaTypeNullability.NON_NULLABLE
    }

internal val DeclarationDescriptorWithVisibility.ktVisibility: Visibility
    get() = when (visibility) {
        DescriptorVisibilities.PUBLIC -> Visibilities.Public