Consider it fixed in 1.0. It is a relic from the days when '=' was
also the equality comparison operator. It also catches typos like
x == 0 # intended: x = 0
which can be relly annoying to find, but I don't think the advantage
of catching those is worth the lack of orthogonality and surprise at
not being able to write "x = v or 'foo'".
--Guido van Rossum, CWI, Amsterdam <Guido.van.Rossum@cwi.nl>