Argument 1 to "load" has incompatible type "HTTPResponse"; expected IO[str]

[lithammer]

Python v3.6
Mypy v0.501

# http.py
import http.client
import json

conn = http.client.HTTPConnection('example.com')
conn.request('GET', '/foobar.json')
response = conn.getresponse()
json.load(response)

Since response is a "file-like object" (i.e. has a .read() method). And json.load(fp, ...) operates on those according to the documentation ("Deserialize fp (a .read()-supporting file-like object containing a JSON document) to a Python object") I expect this to work.

$ mypy http.py
http.py:8: error: Argument 1 to "load" has incompatible type "HTTPResponse"; expected IO[str]

[JelleZijlstra]

Mypy doesn't currently support structural typing, although there is an active proposal to add it (see python/typing#11 and python/peps#224). Once that's implemented we could add a Protocol that defines the read method, but until then I'm not sure there's any better workaround than using cast() or # type: ignore.

[ilevkivskyi]

The original example now passes without errors, so I assume it was fixed in typeshed.