Creating Parent and Child record in the same DML Statement - Illegal assignment from Lead to Id error

Question

Im trying to work out how I can create a parent and child record at the same time. I've tried to base it on the example salesforce have provided https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/langCon_apex_dml_foreign_keys.htm

I'm using the standard leads object as the parent and have a custom object called Lead_account__c as the child. This is a junction object between the lead and account objects.

There is also an external ID field on the lead object called Azure_Lead_ID.

Lead__c is a look up relationship field on the Lead_account__c object up to the lead object

To me it looks like the example in Salesforce doc, but when running the code I get the following error: Line: 7, Column: 1 Illegal assignment from Lead to Id

Lead_Account__c newleadAcc = new Lead_Account__c(Client__c='0013H000002rmNDQAY');

// Create the parent reference.
// Used only for foreign key reference
// and doesn't contain any other fields.
Lead newlead = new Lead(Azure_lead_Id__c='SAP111111');                
newleadAcc.Lead__c = newlead;

// Create the Account object to insert.
// Same as above but has Name field.
// Used for the insert.
Lead parentLead = new Lead(
    LastName='Hallie',
    Company= 'Test Company',
    Azure_lead_Id__c='SAP111111');      

// Create the account and the opportunity.
Database.SaveResult[] results = Database.insert(new SObject[] {
    parentLead, newleadAcc });

// Check results.
for (Integer i = 0; i < results.size(); i++) {
    if (results[i].isSuccess()) {
    System.debug('Successfully created ID: '
          + results[i].getId());
    } else {
    System.debug('Error: could not create sobject '
          + 'for array element ' + i + '.');
    System.debug('   The error reported was: '
          + results[i].getErrors()[0].getMessage() + '\n');
    }
}

Answer 1

You would need to assign the value to the relationship object, not the Id/lookup object. This is __r rather than __c:

newleadAcc.Lead__r = newlead;