Shared and Constants are not instances of respective Variables

[ricardoV94]

Description

import pytensor
import pytensor.tensor as pt
import pytensor.sparse as ps

x = pt.as_tensor([[1, 0, 1.], [0, 1, 0]])
y = pt.exp(x)
assert isinstance(x, pt.TensorConstant)
assert isinstance(x, pt.TensorVariable)
assert not isinstance(y, pt.TensorConstant)
assert isinstance(y, pt.TensorVariable)

x = ps.as_sparse(ps.csr_from_dense(x).eval())
y = ps.structured_exp(x)
assert isinstance(x, ps.SparseConstant)
assert isinstance(x, ps.SparseVariable)  # Fails
assert not isinstance(y, ps.SparseConstant)
assert isinstance(y, ps.SparseVariable)

This was observed in pymc-devs/pymc#7114 (comment)

[ricardoV94]

Similarly, shared variables (dense or sparse) are not instances of TensorVariables either...

DenseTensor Constants also didn't use to be considered instances of DenseTensor Variables until: aesara-devs/aesara#556