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error: Argument 1 to "assert_never" has incompatible type "Direction"; expected "NoReturn"
This is problematic, because the docs also have another example that uses == for comparison and implies that it would work if the second clause would be added.
defchoose_direction(direction: Direction) ->None:
ifdirection==Direction.up:
print('Going up!')
returnassert_never(direction) # E: Argument 1 to "assert_never" has incompatible type "Direction"; expected "NoReturn"
Beyond the docs, this is problematic, because we can have enums that subclass the value type, e.g.
classDirection(str, Enum):
up='up'down='down'
Now it actually makes a difference at runtime whether we compare with is or ==, because == also matches normal strings 'up' and 'down', is does not.
Your Environment
Reproduced in Python 3.9 w/ typing_extensions and Python 3.11, using Mypy 1.0.1.
The text was updated successfully, but these errors were encountered:
The docs contain this example (simplified):
This works. But if we switch to "==" for comparisons, it fails:
error: Argument 1 to "assert_never" has incompatible type "Direction"; expected "NoReturn"
This is problematic, because the docs also have another example that uses
==
for comparison and implies that it would work if the second clause would be added.Beyond the docs, this is problematic, because we can have enums that subclass the value type, e.g.
Now it actually makes a difference at runtime whether we compare with
is
or==
, because==
also matches normal strings'up'
and'down'
,is
does not.Your Environment
Reproduced in Python 3.9 w/ typing_extensions and Python 3.11, using Mypy 1.0.1.
The text was updated successfully, but these errors were encountered: