ruff/crates/ty_python_semantic/resources
Shaygan Hooshyari 988c38c013
[ty] Skip eagerly evaluated scopes for attribute storing (#20856)
## Summary

Fix https://github.com/astral-sh/ty/issues/664

This PR adds support for storing attributes in comprehension scopes (any
eager scope.)

For example in the following code we infer type of `z` correctly:

```py
class C:
    def __init__(self):
        [None for self.z in range(1)]
reveal_type(C().z) # previously [unresolved-attribute] but now shows Unknown | int
```

The fix works by adjusting the following logics:

To identify if an attriute is an assignment to self or cls we need to
check the scope is a method. To allow comprehension scopes here we skip
any eager scope in the check.
Also at this stage the code checks if self or the first method argument
is shadowed by another binding that eager scope to prevent this:

```py
class D:
    g: int

class C:
    def __init__(self):
        [[None for self.g in range(1)] for self in [D()]]
reveal_type(C().g) # [unresolved-attribute]
```

When determining scopes that attributes might be defined after
collecting all the methods of the class the code also returns any
decendant scope that is eager and only has eager parents until the
method scope.

When checking reachability of a attribute definition if the attribute is
defined in an eager scope we use the reachability of the first non eager
scope which must be a method. This allows attributes to be marked as
reachable and be seen.


There are also which I didn't add support for:

```py
class C:
    def __init__(self):
        def f():
            [None for self.z in range(1)]
        f()

reveal_type(C().z) # [unresolved-attribute]
```

In the above example we will not even return the comprehension scope as
an attribute scope because there is a non eager scope (`f` function)
between the comprehension and the `__init__` method

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-11-11 14:45:34 -08:00
..
corpus [ty] Fix panic due to simplifying `Divergent` types out of intersections types (#21253) 2025-11-03 15:41:11 +00:00
mdtest [ty] Skip eagerly evaluated scopes for attribute storing (#20856) 2025-11-11 14:45:34 -08:00
primer [ty] Add cycle handling to `lazy_default` (#20967) 2025-10-23 10:05:08 +02:00
README.md Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00

README.md

Markdown files within the mdtest/ subdirectory are tests of type inference and type checking; executed by the tests/mdtest.rs integration test.

See crates/ty_test/README.md for documentation of this test format.