“'Mapper' 中的 map(From)' 与 'CursorToMessageImpl' 中的 'map(Object)' 冲突；两种方法具有相同的擦除，但都不会覆盖另一个

Question

This is code in kotlin. Showing error Type inference failed: inline fun T.apply(block: T.() -> Unit): T cannot be applied to receiver: Message arguments: (Message.() -> Any).

**map(From)' in 'Mapper' clashes with 'map(Object)' in 'CursorToMessageImpl'; both methods have same erasure, yet neither overrides the other **

class CursorToMessageImpl @Inject constructor(
private val context: Context,
private val cursorToPart: CursorToPart,
private val keys: KeyManager,
private val permissionManager: PermissionManager,
private val preferences: Preferences) : CursorToMessage

{
private val uri = Uri.parse("content://mms-sms/complete-conversations")
    private val projection = arrayOf(
            MmsSms.TYPE_DISCRIMINATOR_COLUMN,
            MmsSms._ID,
            Mms.DATE,
            Mms.DATE_SENT,
            Mms.READ,
            Mms.THREAD_ID,
            Mms.LOCKED,

            Sms.ADDRESS,
            Sms.BODY,
            Sms.SEEN,
            Sms.TYPE,
            Sms.STATUS,
            Sms.ERROR_CODE,

            Mms.SUBJECT,
            Mms.SUBJECT_CHARSET,
            Mms.SEEN,
            Mms.MESSAGE_TYPE,
            Mms.MESSAGE_BOX,
            Mms.DELIVERY_REPORT,
            Mms.READ_REPORT,
            MmsSms.PendingMessages.ERROR_TYPE,
            Mms.STATUS
    )

    override fun map(from: Pair<Cursor, CursorToMessage.MessageColumns>): Message {
        val cursor = from.first
        val columnsMap = from.second

        return Message().apply {
            type = when {
                cursor.getColumnIndex(MmsSms.TYPE_DISCRIMINATOR_COLUMN) != -1 -> cursor.getString(columnsMap.msgType)
                cursor.getColumnIndex(Mms.SUBJECT) != -1 -> "mms"
                cursor.getColumnIndex(Sms.ADDRESS) != -1 -> "sms"
                else -> "unknown"
            }

            id = keys.newId()
            threadId = cursor.getLong(columnsMap.threadId)
            contentId = cursor.getLong(columnsMap.msgId)
            date = cursor.getLong(columnsMap.date)
            dateSent = cursor.getLong(columnsMap.dateSent)
            read = cursor.getInt(columnsMap.read) != 0
            locked = cursor.getInt(columnsMap.locked) != 0
            subId = if (columnsMap.subId != -1) cursor.getInt(columnsMap.subId)

            else -1

            when (type) {
                "sms" -> {
                    address = cursor.getString(columnsMap.smsAddress) ?: ""
                    boxId = cursor.getInt(columnsMap.smsType)
                    seen = cursor.getInt(columnsMap.smsSeen) != 0

                    body = columnsMap.smsBody
                            .takeIf { column -> column != -1 } // The column may not be set
                            ?.let { column -> cursor.getString(column) } ?: "" // cursor.getString() may return null

                    errorCode = cursor.getInt(columnsMap.smsErrorCode)
                    deliveryStatus = cursor.getInt(columnsMap.smsStatus)
                }

                "mms" -> {
                    address = getMmsAddress(contentId)
                    boxId = cursor.getInt(columnsMap.mmsMessageBox)
                    date *= 1000L
                    dateSent *= 1000L
                    seen = cursor.getInt(columnsMap.mmsSeen) != 0
                    mmsDeliveryStatusString = cursor.getString(columnsMap.mmsDeliveryReport) ?: ""
                    errorType = if (columnsMap.mmsErrorType != -1) cursor.getInt(columnsMap.mmsErrorType) else 0
                    messageSize = 0
                    readReportString = cursor.getString(columnsMap.mmsReadReport) ?: ""
                    messageType = cursor.getInt(columnsMap.mmsMessageType)
                    mmsStatus = cursor.getInt(columnsMap.mmsStatus)
                    val subjectCharset = cursor.getInt(columnsMap.mmsSubjectCharset)
                    subject = cursor.getString(columnsMap.mmsSubject)
                            ?.takeIf { it.isNotBlank() }
                            ?.let(_root_ide_package_.app.google.android.mms.pdu_alt.PduPersister::getBytes)
                            ?.let { _root_ide_package_.app.google.android.mms.pdu_alt.EncodedStringValue(subjectCharset, it).string } ?: ""
                    textContentType = ""
                    attachmentType = Message.AttachmentType.NOT_LOADED

                    parts.addAll(cursorToPart.getPartsCursor(contentId)?.map { cursorToPart.map(it) } ?: listOf())
                }
                else -> -1
            }
        }
    }


**and interference mapper is :-**


interface Mapper<in From, out To> {

    fun map(from: From): To
}

Answer 1

I'm not 100% sure this is your issue, but since else -> -1 in your when statement doesn't accomplish anything, try removing it. A when statement doesn't have to be exhaustive when it isn't being forced to be evaluated as an expression (by assigning its result to a variable or property).

else -> -1 at the bottom of your when statement causes it to be a when expression that returns Any . Usually, the compiler can interpret a lambda ending in an expression other than Unit as having an implicit return of Unit if there are no overloads that it would otherwise match. But there may be some cases where the involved classes are complex enough to prevent it from deducing that.