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Final (context-sensitive Literal) doesn't support type narrowing #19814
Description
Bug Report
Maybe there's a reason this is not supported, but at a quick look it seems like it should work. When a union of context-sensitive Literals are used, it fails to perform type narrowing, whereas explicit Literals do work.
To Reproduce
from typing import Final, Literal
class TXTRecord:
type: Final = "TXT"
text: str = "Foo"
class ARecord:
type: Final = "A"
host: str = "192.168.1.1"
record: TXTRecord | ARecord
reveal_type(record.type)
if record.type == "TXT":
print(record.text) # error with Final, but not with Literal
else:
print(record.host) # error with Final, but not with Literal
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