Yield self is inferred to be of a mistaken type

[doranid]

Steps to reproduce

1. Run the following

import astroid


print(list(astroid.parse('''
import contextlib

class A:
    @contextlib.contextmanager
    def get(self):
        yield self

class B(A):
    def play():
        pass

with B().get() as b:
    b.play()
''').ilookup('b')))

Current behavior

Prints [<Instance of .A at 0x...>]

Expected behavior

Prints [<Instance of .B at 0x...>]

python -c "from astroid import __pkginfo__; print(__pkginfo__.version)" output

2.6.2

[jacobtylerwalls]

Possible duplicate of #1008

[doranid]

This problem is due to the fact _infer_context_manager takes caller function, using its current context, instead of the original callers context. This may be fixed for example by adding data to Generator instance, by infer_call_result that signifies its possible value types.

I'm not familiar with the codebase, it seems to me that that this is not the correct approach, but, the correct approach is to pass this data inside the context structure. But it's not clear to me how to do that.