You are doing insert operation(insert clonelist) in which you are accessing Converted lead Id value in a field. You can't use converted LeadId field in DML operations. Below is the Sample code that will work-
trigger ConvertedLead_Trigger on Lead (after update) {
Map<Id, Lead> cl = new Map<Id,Lead>();
Lead parent;
List<Contact> clist = new List<Contact>();
Set<Id> convertedids = new Set<Id>();
//list of converted leads
for (Lead t:Trigger.new){
Lead ol = Trigger.oldMap.get(t.ID);
if(t.IsConverted == true && ol.isConverted == false)
{
cl.put(t.Id, t);
convertedids.add(t.ConvertedContactId);
}
}
Set<Id> leadIds = cl.keySet();
List<ConvertLeadTest__c> mp =[Select Id,Name,Lead__c, Account__c,Opportunity__c from ConvertLeadTest__c where Lead__c in :leadIds];
List<ConvertLeadTest__c> mp1=new List<ConvertLeadTest__c>();
List<ConvertLeadTest__c> mp2=new List<ConvertLeadTest__c>();
for(ConvertLeadTest__c cc:mp)
{
if(cl.containsKey(cc.Lead__c))
{
cc.Account__c=cl.get(cc.Lead__c).ConvertedAccountId;
cc.Opportunity__c=cl.get(cc.Lead__c).ConvertedOpportunityId;
mp1.add(cc);
mp2.add(new ConvertLeadTest__c(Account__c=cl.get(cc.Lead__c).ConvertedAccountId,Opportunity__c=cl.get(cc.Lead__c).ConvertedOpportunityId));
}
}
update mp;
insert mp2;
}
But if you write ConvertLeadTest__c(Lead__c=cc.Lead__c,Account__c=cl.get(cc.Lead__c).ConvertedAccountId,Opportunity__c=cl.get(cc.Lead__c).ConvertedOpportunityId)); then it will throw error.
Hope this will help you.
Thanks :)