NCubeInterior equality ignores parametric bounds, and is inconsistent with its hash #198

Two NCubeInterior objects with the same name but different parametric bounds compare equal, but they have different hashes. This breaks Python's requirement that a == b implies hash(a) == hash(b).

Reproduced with SymPDE 0.20.0:

from sympde.topology import Square

P = Square('P', bounds1=(0, 1), bounds2=(0, 1)).interior
Q = Square('P', bounds1=(0, 2), bounds2=(0, 1)).interior

P.min_coords, P.max_coords      # ((0.0, 0.0), (1.0, 1.0))
Q.min_coords, Q.max_coords      # ((0.0, 0.0), (2.0, 1.0))

P == Q                          # True: equality ignores the bounds
hash(P) == hash(Q)              # False: sets disagree with ==

P._hashable_content() returns only ('P',), so == compares names only, while the hash depends on other data as well.

Expected

Patches with different bounds compare unequal, and __eq__ and __hash__ agree. Including min_coords and max_coords in _hashable_content would probably fix both.

Context

In PSYDAC we need to check that a user-given domain matches the domain stored in a geometry file. Because of this bug we have to compare the bounds explicitly.