ruff/crates/ty_python_semantic/resources/mdtest/narrow
Alex Waygood 529d81daca
Some checks are pending
CI / Determine changes (push) Waiting to run
CI / cargo fmt (push) Waiting to run
CI / cargo clippy (push) Blocked by required conditions
CI / cargo test (linux) (push) Blocked by required conditions
CI / cargo test (linux, release) (push) Blocked by required conditions
CI / cargo test (windows) (push) Blocked by required conditions
CI / cargo test (wasm) (push) Blocked by required conditions
CI / cargo build (release) (push) Waiting to run
CI / cargo build (msrv) (push) Blocked by required conditions
CI / cargo fuzz build (push) Blocked by required conditions
CI / fuzz parser (push) Blocked by required conditions
CI / test scripts (push) Blocked by required conditions
CI / ecosystem (push) Blocked by required conditions
CI / Fuzz for new ty panics (push) Blocked by required conditions
CI / cargo shear (push) Blocked by required conditions
CI / python package (push) Waiting to run
CI / pre-commit (push) Waiting to run
CI / mkdocs (push) Waiting to run
CI / formatter instabilities and black similarity (push) Blocked by required conditions
CI / test ruff-lsp (push) Blocked by required conditions
CI / check playground (push) Blocked by required conditions
CI / benchmarks-instrumented (push) Blocked by required conditions
CI / benchmarks-walltime (push) Blocked by required conditions
[ty Playground] Release / publish (push) Waiting to run
[ty] Improve subscript narrowing for "safe mutable classes" (#19781)
## Summary

This PR improves the `is_safe_mutable_class` function in `infer.rs` in
several ways:
- It uses `KnownClass::to_instance()` for all "safe mutable classes".
Previously, we were using `SpecialFormType::instance_fallback()` for
some variants -- I'm not totally sure why. Switching to
`KnownClass::to_instance()` for all "safe mutable classes" fixes a
number of TODOs in the `assignment.md` mdtest suite
- Rather than eagerly calling `.to_instance(db)` on all "safe mutable
classes" every time `is_safe_mutable_class` is called, we now only call
it lazily on each element, allowing us to short-circuit more
effectively.
- I removed the entry entirely for `TypedDict` from the list of "safe
mutable classes", as it's not correct.
`SpecialFormType::TypedDict.instance_fallback(db)` just returns an
instance type representing "any instance of `typing._SpecialForm`",
which I don't think was the intent of this code. No tests fail as a
result of removing this entry, as we already check separately whether an
object is an inhabitant of a `TypedDict` type (and consider that object
safe-mutable if so!).

## Test Plan

mdtests updated
2025-08-06 12:26:25 +01:00
..
conditionals [ty] fix incorrect lazy scope narrowing (#19744) 2025-08-04 20:32:08 -07:00
assert.md
assignment.md [ty] Improve subscript narrowing for "safe mutable classes" (#19781) 2025-08-06 12:26:25 +01:00
bool-call.md
boolean.md
complex_target.md [ty] Track different uses of legacy typevars, including context when rendering typevars (#19604) 2025-08-01 12:20:32 -04:00
hasattr.md [ty] Attribute access on intersections with negative parts (#19524) 2025-07-25 14:56:14 +02:00
isinstance.md [ty] Support narrowing on isinstance()/issubclass() if the second argument is a dynamic, intersection, union or typevar type (#18900) 2025-06-24 10:55:26 +00:00
issubclass.md [ty] Support narrowing on isinstance()/issubclass() if the second argument is a dynamic, intersection, union or typevar type (#18900) 2025-06-24 10:55:26 +00:00
match.md [ty] Improve disjointness inference for NominalInstanceTypes and SubclassOfTypes (#18864) 2025-06-24 20:27:37 +00:00
post_if_statement.md
truthiness.md [ty] Reachability constraints (#18621) 2025-06-17 09:24:28 +02:00
type.md [ty] Surface matched overload diagnostic directly (#18452) 2025-06-20 08:36:49 +05:30
type_guards.md [ty] Splat variadic arguments into parameter list (#18996) 2025-07-22 14:33:08 -04:00
while.md [ty] Eagerly simplify 'True' and 'False' constraints (#18998) 2025-06-30 13:11:52 +02:00