Remove unused `# type: ignore`s (#12531)

Over time we've begun to use newer versions of mypy, typeshed, stub
packages---and of course we've improved our own annotations. This makes
some type ignore comments no longer necessary. I have removed them.

There was one exception: a module that imports `select.epoll`. The
ignore is redundant on Linux, but I've kept it ignored for those of us
who work on the source tree using not-Linux. (#11771)

I'm more interested in the config line which enforces this. I want
unused ignores to be reported, because I think it's useful feedback when
annotating to know when you've fixed a problem you had to previously
ignore.

* Installing extras before typechecking

Lacking an easy way to install all extras generically, let's bite the bullet and
make install the hand-maintained `all` extra before typechecking.

Now that https://github.com/matrix-org/backend-meta/pull/6 is merged to
the release/v1 branch.

1 files changed, 6 insertions, 0 deletions

diff --git a/mypy.ini b/mypy.ini
index a663bf6975..280f1e898e 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -7,6 +7,7 @@ show_error_codes = True
 show_traceback = True
 mypy_path = stubs
 warn_unreachable = True
+warn_unused_ignores = True
 local_partial_types = True
 no_implicit_optional = True
 
@@ -134,6 +135,11 @@ disallow_untyped_defs = True
 [mypy-synapse.metrics.*]
 disallow_untyped_defs = True
 
+[mypy-synapse.metrics._reactor_metrics]
+# This module imports select.epoll. That exists on Linux, but doesn't on macOS.
+# See https://github.com/matrix-org/synapse/pull/11771.
+warn_unused_ignores = False
+
 [mypy-synapse.module_api.*]
 disallow_untyped_defs = True