At present, FeatureHasher (and HashingVectorizer) is not supported with PyPy because it relies on interacting with array.array from Cython which is not supported and probably won't be in the near future (cf cython/cython#1818 and bitbucket.org/pypy/pypy#2807).

Following workarounds were proposed in #11010, briefly,

• use a separate pure python implementation for _hashing.py specific PyPy [MRG] PyPy support #11010 (comment)
• convert the current _hashing.pyx to cython's pure-python mode together with an external pxd ([MRG] PyPy support #11010 (comment))
• use a different data structure instead of array.array ([MRG] PyPy support #11010 (comment))