  
  
  class Exists(Subquery):
      template = 'EXISTS(%(subquery)s)'
  
      def __init__(self, *args, negated=False, **kwargs):
          self.negated = negated
          super().__init__(*args, **kwargs)
  
 
</s> remove 
    def __init__(self, *args, output_field=None, **kwargs):
        super().__init__(*args, output_field=TimeField(), **kwargs)
 </s> add     output_field = TimeField() </s> remove 
    def __init__(self, *args, output_field=None, **kwargs):
        super().__init__(*args, output_field=DateField(), **kwargs)
 </s> add     output_field = DateField() </s> remove 
    def __init__(self, output_field=None, **extra):
        if output_field is None:
            output_field = UUIDField()
        super().__init__(output_field=output_field, **extra)
 </s> add     output_field = UUIDField() </s> remove 
    def __init__(self, output_field=None, **extra):
        if output_field is None:
            output_field = DateTimeField()
        super().__init__(output_field=output_field, **extra)
 </s> add     output_field = DateTimeField() </s> remove     @property
    def output_field(self):
        return fields.BooleanField()

 </s> add 
    output_field = fields.BooleanField()
  
  
  class Exists(Subquery):
      template = 'EXISTS(%(subquery)s)'
    output_field = fields.BooleanField()
  
      def __init__(self, *args, negated=False, **kwargs):
          self.negated = negated
          super().__init__(*args, **kwargs)
  
keep keep keep add keep keep keep keep keep
 Fixed #28492 -- Defined default output_field of expressions at the class level.

This wasn't possible when settings were accessed during Field initialization
time as our test suite setup script was triggering imports of expressions
before settings were configured. 
django/db/models/expressions.py