Incompatible typehints for Sphinx and mypy

[fjarri]

Currently, for mypy 0.770, sphinx 3.5.2, their requirements for typehints are contradictory.

In order for typehints to hyperlink properly in the docs, sphinx needs from __future__ import annotations and, in some cases, fully qualified type names (with all the outer namespaces present).

On the other hand, mypy does not need the __future__ import (and, in fact, not having it adds a compile-time check that the types are available), and does not handle fully qualified type names correctly.

The current choice is to side with Sphinx since the documentation is more important. Perhaps it will be resolved in future versions (e.g. Sphinx 4.0).