David Peter 1fe958c694 [ty] Implicit type aliases: Support for PEP 604 unions (#21195) ...

## Summary

Add support for implicit type aliases that use PEP 604 unions:
```py
IntOrStr = int | str

reveal_type(IntOrStr)  # UnionType

def _(int_or_str: IntOrStr):
    reveal_type(int_or_str)  # int | str
```

## Typing conformance

The changes are either removed false positives, or new diagnostics due
to known limitations unrelated to this PR.

## Ecosystem impact

Spot checked, a mix of true positives and known limitations.

## Test Plan

New Markdown tests.

2025-11-03 21:50:25 +01:00

..

conditionals

[ty] Use declared variable types as bidirectional type context (#20796)

2025-10-16 15:40:39 -04:00

assert.md

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

assignment.md

[ty] No union with Unknown for module-global symbols (#20664)

2025-10-01 16:40:30 +02:00

bool-call.md

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

boolean.md

[ty] Consider __len__ when determining the truthiness of an instance of a tuple class or a @final class (#21049)

2025-10-24 09:29:55 +00:00

complex_target.md

[ty] No union with Unknown for module-global symbols (#20664)

2025-10-01 16:40:30 +02:00

hasattr.md

[ty] Improve error messages for unresolved attribute diagnostics (#20963)

2025-10-19 10:58:25 +01:00

isinstance.md

[ty] Implicit type aliases: Support for PEP 604 unions (#21195)

2025-11-03 21:50:25 +01:00

issubclass.md

[ty] Implicit type aliases: Support for PEP 604 unions (#21195)

2025-11-03 21:50:25 +01:00

match.md

[ty] Use the top materialization of classes for narrowing in class-patterns for match statements (#21150)

2025-10-30 20:44:51 +00:00

post_if_statement.md

Rename Red Knot (#17820)

2025-05-03 19:49:15 +02:00

truthiness.md

[ty] Reachability constraints (#18621)

2025-06-17 09:24:28 +02:00

type_guards.md

[ty] Filter out revealed-type and undefined-reveal diagnostics from mdtest snapshots (#20820)

2025-10-12 18:39:32 +00:00

type.md

[ty] linear variance inference for PEP-695 type parameters (#18713)

2025-08-19 17:54:09 -07:00

while.md

[ty] Eagerly simplify 'True' and 'False' constraints (#18998)

2025-06-30 13:11:52 +02:00