import org.jetbrains.kotlin.config.ApiVersion
import org.jetbrains.kotlin.config.LanguageFeature
import org.jetbrains.kotlin.config.LanguageVersionSettings
import org.jetbrains.kotlin.contracts.description.EventOccurrencesRange
import org.jetbrains.kotlin.descriptors.ClassKind
import org.jetbrains.kotlin.descriptors.EffectiveVisibility
import org.jetbrains.kotlin.descriptors.Visibility

        val subject: KtExpression
        val description: String
        val isCastToNotNull: Boolean
    }

    interface SmartcastImpossibleOnImplicitInvokeReceiver : KtFirDiagnostic<KtExpression> {
        override val diagnosticClass get() = SmartcastImpossibleOnImplicitInvokeReceiver::class
        val desiredType: KtType
        val subject: KtExpression
        val description: String
        val isCastToNotNull: Boolean

        ExpressionExpectedPackageFoundImpl(
            firDiagnostic as KtPsiDiagnostic,
            token,
        )
    }
    add(FirErrors.ERROR_IN_CONTRACT_DESCRIPTION) { firDiagnostic ->
        ErrorInContractDescriptionImpl(
            firDiagnostic.a,
            firDiagnostic as KtPsiDiagnostic,
            token,
        )
    }