Steps to reproduce:

1. Create a item "item" on for example 10 hosts with value "1" and 10 with value 0.
2. Create calculated item: count(last_foreach(//item[]),"eq",1) or count(//item[]),"eq",1)

Result:
Cannot evaluate function: invalid first argument at 'count(last_foreach(/*/item[]),"eq",1)'

Expected:
Should return 10.