fix: don't panic on a non-generic classproperty in get_attributes

[renz011tzar]

Fixes #4453.

get_kind_and_field_type matched classproperty / cached_classproperty on the class name alone, then unwrapped the first type argument:

Type::ClassType(c)
    if c.name() == "classproperty" || c.name() == "cached_classproperty" =>
{
    let result_ty = c.targs().as_slice().first().unwrap();

A class with that name but no type arguments reaches this arm with empty targs, so get_attributes panics.

Change

Per @yangdanny97's suggestion in the issue, the no-type-arguments case now behaves as (None, ty). Rather than adding a nested match, the check moves into the match guard, so such a class simply doesn't match this arm and falls through to the existing _ => (None, ty):

Type::ClassType(c)
    if (c.name() == "classproperty" || c.name() == "cached_classproperty")
        && let Some(result_ty) = c.targs().as_slice().first() =>
{
    (Some(String::from("property")), result_ty)
}

Testing

Adds test_get_attributes_non_generic_classproperty, following the existing TempDir + create_query() pattern in test/query.rs. It checks out a module defining a plain class classproperty: used as a decorator, and asserts get_attributes returns the attribute rather than panicking.

• The test fails without the fix (panicked at pyrefly/lib/query.rs:1147:66: called Option::unwrap() on a None value) and passes with it.
• cargo test -p pyrefly --lib test::query — 7 passed, 0 failed.
• cargo fmt --check clean.

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[meta-codesync]

This pull request has been imported. If you are a Meta employee, you can view this in D114848162. (Because this pull request was imported automatically, there will not be any future comments.)

[yangdanny97]

Review automatically exported from Phabricator review in Meta.

[meta-codesync]

@ndmitchell merged this pull request in 1ba9829.