[IDEA] Generic `Never` for more explicit exception type-hinting

Ideas
1

In one sentence: allow Never to be generic, bound to BaseException.

@overload
def divide(a, b: Literal[0]) -> Never[ZeroDivisionError]:...
@overload 
def divide(a: int, b: int) -> float: ...
def divide(a, b) : return a/b

try:
    divide(5, 0)  # ✔ ZeroDivisionError wrapped in correct try-except block
except ZeroDivisionError:
    ...

try:
    divide(5, 0)  # ✘ type-checker can produce 2 messages
   # [uncaught-exception] divide(5, 0) raises ZeroDivisionError
   # Note: ValueError does not cover ZeroDivisionError
except ValueError:
    ...

divide(5, 0)  # ✘ [uncaught-exception] raises ZeroDivisionError

Non-generic Never should remain unchanged. try-except-blocks act like type: ignore statements. TypingError: type checker will emit error with a message specified in typing stubs · Issue #1043 · python/typing · GitHub

2

See previous discussions on checked exceptions, the conclusion of which were:

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