QuerySet with multiple annotations crashes with "unhashable type: 'Point'"

[Lachlan Cannon]

Simplified example to reproduce, with these models:

class State(models.Model):
    name = models.CharField(max_length=100)

class Locality(models.Model):
    name = models.CharField(max_length=100)
    location = models.PointField(geography=True)
    state = models.ForeignKey(State, on_delete=models.CASCADE)

Running the following code works fine in 2.0 (assuming you have a few models set up):

State.objects.annotate(distance=Distance('locality__location', Locality.objects.first().location))

But this code works in 1.11, and fails in 2.0.1 with TypeError: unhashable type: 'Point':

State.objects.annotate(distance=Distance('locality__location', self.locality.location)).annotate(count=Count('locality'))

[Tim Graham]

Bisected to 19b2dfd1bfe7fd716dd3d8bfa5f972070d83b42f.

[Mariusz Felisiak]

​PR

[GitHub <noreply@…>]

In b002a032:

Fixed #29054 -- Fixed a regression where a queryset that annotates with geometry objects crashes.

Made GEOSGeometryBase hashable.
Regression in 19b2dfd1bfe7fd716dd3d8bfa5f972070d83b42f.

Thanks Tim Graham for the review.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 42622b89:

[2.0.x] Fixed #29054 -- Fixed a regression where a queryset that annotates with geometry objects crashes.

Made GEOSGeometryBase hashable.
Regression in 19b2dfd1bfe7fd716dd3d8bfa5f972070d83b42f.

Thanks Tim Graham for the review.
Backport of b002a032f90b8cd228cfcee6c88cd238a8191cc0 from master