78b5f0b165
## Summary This PR closes #16248. If the return type of the function isn't assignable to the one specified, an `invalid-return-type` error occurs. I thought it would be better to report this as a different kind of error than the `invalid-assignment` error, so I defined this as a new error. ## Test Plan All type inconsistencies in the test cases have been replaced with appropriate ones. --------- Co-authored-by: Carl Meyer <carl@astral.sh>
995 B
995 B
Narrowing for match statements
Single match pattern
def _(flag: bool):
x = None if flag else 1
reveal_type(x) # revealed: None | Literal[1]
y = 0
match x:
case None:
y = x
reveal_type(y) # revealed: Literal[0] | None
Class patterns
def get_object() -> object:
return object()
class A: ...
class B: ...
x = get_object()
reveal_type(x) # revealed: object
match x:
case A():
reveal_type(x) # revealed: A
case B():
# TODO could be `B & ~A`
reveal_type(x) # revealed: B
reveal_type(x) # revealed: object
Class pattern with guard
def get_object() -> object:
return object()
class A:
def y() -> int:
return 1
class B: ...
x = get_object()
reveal_type(x) # revealed: object
match x:
case A() if reveal_type(x): # revealed: A
pass
case B() if reveal_type(x): # revealed: B
pass
reveal_type(x) # revealed: object