Compile error: "Variable Trigger does not exist" in a Trigger

Question

Just want to know what am I missing here.

trigger updateLastCallDate on Task (after insert, after update, after delete) {

    Set<Id> con_set = new Set<Id>();

    List<Contact> con_list = new List<Contact>();

    for(Task T: Trigger.new()){
        if(String.valueof(T.WhatId).startsWith('001') &&
            T.Status=='Completed' && T.Subject=='Call' ) {
            con_set.add(T.WhatId);
        }
     }

     for (AggregateResult aggregateResult: [SELECT max(createdDate)MaxCDate, WhatId
        FROM Task WHERE WhatID IN: con_set AND Status ='Completed'
        AND Subject ='Call' Group By WhatId]) {
        con_list.add(new Contact(Id=(id)aggregateResult.get('WhatId'),Last_Call__c=date.valueof(aggregateResult.get('MaxCDate'))));
     }

     try {
         if(con_list !=null && con_list.size()>0) {
             update con_list;
         }
     } catch(Exception e) {
         system.debug('Exception ***'+e.getMessage());
     }
  }

Answer 1

The compile error is because you have this:

for(Task T: Trigger.new()){

so the compiler thinks .new() is a method on a variable named Trigger, when it's actually a system context variable. It should be:

for (Task t : trigger.new) {