I think we can safely remove the following two lines of code in TimeEntryQuery#sql_for_activity_id_field because the variable condition_on_id and condition_on_parent_id are never been used.

diff --git a/app/models/time_entry_query.rb b/app/models/time_entry_query.rb
index f974ab6d9..e1cb753ad 100644
--- a/app/models/time_entry_query.rb
+++ b/app/models/time_entry_query.rb
@@ -190,18 +190,16 @@ class TimeEntryQuery < Query
         "#{TimeEntry.table_name}.issue_id NOT IN (#{issue_ids.join(',')})"
       else
         "1=1"
       end
     end
   end
 
   def sql_for_activity_id_field(field, operator, value)
-    condition_on_id = sql_for_field(field, operator, value, Enumeration.table_name, 'id')
-    condition_on_parent_id = sql_for_field(field, operator, value, Enumeration.table_name, 'parent_id')
     ids = value.map(&:to_i).join(',')
     table_name = Enumeration.table_name
     if operator == '='
       "(#{table_name}.id IN (#{ids}) OR #{table_name}.parent_id IN (#{ids}))"
     else
       "(#{table_name}.id NOT IN (#{ids}) AND (#{table_name}.parent_id IS NULL OR #{table_name}.parent_id NOT IN (#{ids})))"
     end
   end