the Apex class:

public with sharing class AcctActivityList{
  
    public Account acct {get; set;}
    public List<ActivityHistory> ClosedTasks {get; set;}
    string mail = 'mail';
  
    public AcctActivityList(ApexPages.StandardController stdcontroller) {
        //get account
        acct = (Account)stdController.getRecord();
        //get activity history - can't query activity history directly, just in a subquery against another object

        SObject[] ActivityHistory = [Select id, (select Id, AccountId, Account.Name, ActivityDate, ActivityType, Description, OwnerId, Subject,
                                        LastModifiedDate, IsTask, WhatId, WhoId from ActivityHistories where
                                        (ActivityType !='Email' or Subject.contains('email')) ORDER by ActivityDate DESC)
                           from Account where Id =: acct.id];
      
        ClosedTasks = (List<ActivityHistory>)ActivityHistory.get(0).getSObjects('ActivityHistories');
      
    }
}


Why is my string.contains filter not working (i.e. why can't I save the code)?
When I try to save, I get the error: unexpected token: 'email'. The same is true if the filter is Subject.contains('email') == false.

I've seen this string class referenced various places around the web and it's still not working. I also tried reverting to API 27 (it was on 29) in case there was a bug in that API. No go.