A couple interesting observations with the existing behavior of CallableType and mypy/messages.py's pretty_callable (below)

First, when printing B.f in testInvalidOverrideArgumentCountWithImplicitSignature2 and I.g in testAbstractClassWithAllDynamicTypes, the output of both did not contain "self". Upon some investigation, isinstance(tp.definition, FuncDef) is False and then tp.def_extras.get('first_arg') is None. I'm guessing this might be since both have implicit return types and that might be interacting somehow with CallableType?

[case testInvalidOverrideArgumentCountWithImplicitSignature2]
...
class B:
    def f(self, x, y): pass
...
main:5: note:      Superclass:
main:5: note:          def f(x: Any, y: Any) -> Any
-- expected this instead? def f(self, x: Any, y: Any) -> Any

Second, I had to split testOverloadedMethodSupertype and testFinalBodyReprocessedAndStillFinalOverloaded into an only_when_cache and only_when_nocache version. Similar to what I described above, in the only_when_nocache versions, isinstance(tp.definition, FuncDef) is False. However, in the only_when_cache versions, it is True and "self" is included in the output

Not sure if this is expected behavior or a bug. Let me know what you think!

@atakiar Could you look into some of the mypy_primer errors? I'm a little nervous about all of the missing errors, though it wouldn't shock me if some of them had been wrong?

@msullivan I think new commits made their way to master between my last merge and when the mypy_primer workflow ran (triggered manually for first-time mypy contributors). Trying this again, hopefully it’ll come out looking better this time!

@msullivan let me know what you think!

By the way, the missing mypy_primer errors are the result of #10579. The new multiline note along with the restriction on number of errors shown, results in the last few errors now being hidden

Diff from mypy_primer, showing the effect of this PR on open source code:

aioredis (https://github.com/aio-libs/aioredis.git)
+ aioredis/client.py:4286: note:      Superclass:
+ aioredis/client.py:4286: note:          def (self: Redis) -> Any
+ aioredis/client.py:4286: note:      Subclass:
+ aioredis/client.py:4286: note:          def __aenter__(self) -> Coroutine[Any, Any, Pipeline]