Summary
Hello, I ran into this (I did quickly check the issues but sorry if this a duplicate):
def main_1(paths: Sequence[str]) -> None:
match paths:
case []:
value = 0
case [_first]:
value = 1
case [_first, _second]:
value = 2
case [*_paths]:
raise ValueError
print(value) # error[possibly-unresolved-reference] from ty. OK for mypy.
def main_2(paths: Sequence[str]) -> None:
match paths:
case []:
value = 0
case [first]:
value = 1
case [_first, _second]:
value = 2
case [_first, _second, *_paths]:
raise ValueError
print(value) # error[possibly-unresolved-reference] from ty. OK for mypy.Here all cases are clearly handled, so it would be nice to detect that the variable will always be assigned. Mypy does, apparently.
What's kind of strange is that the following works for ty, but not for mypy:
def main_3(paths: Sequence[str]) -> int: # mypy error: Missing return statement. OK for ty
match paths:
case []:
return 0
case [first]:
return 1
case [first, second]:
return 2
case [first, second, *_paths]:
raise ValueErrorVersion
ty 0.0.32 (4d1e1fc 2026-04-20)
Summary
Hello, I ran into this (I did quickly check the issues but sorry if this a duplicate):
Here all cases are clearly handled, so it would be nice to detect that the variable will always be assigned. Mypy does, apparently.
What's kind of strange is that the following works for ty, but not for mypy:Version
ty 0.0.32 (4d1e1fc 2026-04-20)