Commit Graph

558 Commits

Author SHA1 Message Date
David Peter 75f3c0e8e6
[ty] Respect `dataclass_transform` parameters for metaclass-based models (#20780)
## Summary

Respect parameters such as `frozen_default` for metaclass-based
`@dataclass_transformer` models.

Related to: https://github.com/astral-sh/ty/issues/1260

## Typing conformance changes

Those are all correct (new true positives)

## Test Plan

New Markdown tests
2025-10-09 13:24:20 +00:00
wangxiaolei f0d0b57900
[ty] `dataclass_transform`: Support `frozen_default` and `kw_only_default` (#20761)
## Summary

- Add support for eq, kw_only, and frozen parameter overrides in
@dataclass_transform
- Previously only order parameter override was supported
- Update test documentation to reflect fixed behavior
- Resolves issue where kw_only_default and frozen_default could not be
overridden

closes https://github.com/astral-sh/ty/issues/1260

## Test Plan

New Markdown tests

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-10-09 09:34:49 +02:00
Alex Waygood f054b8a55e
[ty] Improve assignability/subtyping between two protocol types (#20368) 2025-10-08 18:37:30 +00:00
Alex Waygood b9c84add07
[ty] Disambiguate classes that live in different modules but have the same fully qualified names (#20756)
## Summary

Even disambiguating classes using their fully qualified names is not
enough for some diagnostics. We've seen real-world examples in the
ecosystem (and https://github.com/astral-sh/ruff/pull/20368 introduces
some more!) where two types can be different, but can still have the
same fully qualified name. In these cases, our disambiguation machinery
needs to print the file path and line number of the class in order to
disambiguate classes with similar names in our diagnostics.

Helps with https://github.com/astral-sh/ty/issues/1306

## Test Plan

Mdtests
2025-10-08 18:27:40 +01:00
David Peter 150ea92d03
[ty] Add tests for instance attributes in class hierarchies (#20767)
## Summary

This adds a couple of new test cases related to
https://github.com/astral-sh/ty/issues/1067 and beyond that. For now,
they are just documenting the current (problematic) behavior. Since the
topic has some subtleties, I'd like to merge this prior to the actual
bugfix(es) in order to evaluate the changes in an easier way.
2025-10-08 17:46:47 +02:00
David Peter 6b94e620fe
[ty] Fix accidental Liskov violation in protocol tests (#20763)
## Summary

We have the following test in `protocols.md`:
```py
class HasX(Protocol):
    x: int

# […]

class Foo:
    x: int

# […]

class FooBool(Foo):
    x: bool

static_assert(not is_subtype_of(FooBool, HasX))
static_assert(not is_assignable_to(FooBool, HasX))
```

If `Foo` was indeed intended to be a base class of `FooBool`, then `x:
bool` should be reported as a Liskov violation. And then it's a matter
of definition whether or not these assertions should hold true or not
(should the incorrect override take precedence or not?). So it looks to
me like this is just an oversight, probably a copy-paste error from
another test right before it, where `FooSub` is indeed intended to be a
subclass of `Foo`.

I am fixing this because this test started to fail on a branch of mine
that changes how attribute lookup in inheritance chains works.
2025-10-08 14:04:37 +02:00
Mark Z. Ding f95eb90951
[ty] Truncate type display for long unions in some situations (#20730)
## Summary

Fixes [astral-sh/ty#1307](https://github.com/astral-sh/ty/issues/1307)

Unions with length <= 5 are unaffected to minimize test churn
Unions with length > 5 will only display the first 3 elements + "...
omitted x union elements"
Here "length" is defined as the number of elements after condensation to
literals

Edit: we no longer truncate in revel case. 
Before:

> info: Attempted to call union type `(def f1() -> int) | (def f2(name:
str) -> int) | (def f3(a: int, b: int) -> int) | (def f4[T](x: T@f4) ->
int) | Literal[5] | (Overload[() -> None, (x: str) -> str]) |
(Overload[() -> None, (x: str, y: str) -> str]) | PossiblyNotCallable`

After:

> info: Attempted to call union type `(def f1() -> int) | (def f2(name:
str) -> int) | (def f3(a: int, b: int) -> int) | ... omitted 5 union
elements`

The below comparisons are outdated, but left here as a reference.

Before:
```reveal_type(x)  # revealed: Literal[1, 2] | A | B | C | D | E | F | G```
```reveal_type(x) # revealed: Result1A | Result1B | Result2A | Result2B
| Result3 | Result4```
After:
```reveal_type(x)  # revealed: Literal[1, 2] | A | B | ... omitted 5 union elements```
```reveal_type(x) # revealed: Result1A | Result1B | Result2A | ...
omitted 3 union elements```

This formatting is consistent with
`crates/ty_python_semantic/src/types/call/bind.rs` line 2992

## Test Plan

Cosmetic only, covered and verified by changes in mdtest
2025-10-08 11:21:26 +01:00
David Peter 1f1542db51
[ty] Use 3.14 as the default version (#20759)
## Summary

Bump the latest supported Python version of ty to 3.14 and updates some
references from 3.13 to 3.14.

This also fixes a bug with `dataclasses.field` on 3.14 (which adds a new
keyword-only parameter to that function, breaking our previously naive
matching on the parameter structure of that function).

## Test Plan

A `ty check` on a file with template strings (without any further
configuration) doesn't raise errors anymore.
2025-10-08 11:38:47 +02:00
Carl Meyer 5d3a35e071
[ty] fix implicit Self on generic class with typevar default (#20754)
## Summary

Typevar attributes (bound/constraints/default) can be either lazily
evaluated or eagerly evaluated. Currently they are lazily evaluated for
PEP 695 typevars, and eager for legacy and synthetic typevars.
https://github.com/astral-sh/ruff/pull/20598 will make them lazy also
for legacy typevars, and the ecosystem report on that PR surfaced the
issue fixed here (because legacy typevars are much more common in the
ecosystem than PEP 695 typevars.)

Applying a transform to a typevar (normalization, materialization, or
mark-inferable) will reify all lazy attributes and create a new typevar
with eager attributes. In terms of Salsa identity, this transformed
typevar will be considered different from the original typevar, whether
or not the attributes were actually transformed.

In general, this is not a problem, since all typevars in a given generic
context will be transformed, or not, together.

The exception to this was implicit-self vs explicit Self annotations.
The typevar we created for implicit self was created initially using
inferable typevars, whereas an explicit Self annotation is initially
non-inferable, then transformed via mark-inferable when accessed as part
of a function signature. If the containing class (which becomes the
upper bound of `Self`) is generic, and has e.g. a lazily-evaluated
default, then the explicit-Self annotation will reify that default in
the upper bound, and the implicit-self would not, leading them to be
treated as different typevars, and causing us to fail to solve a call to
a method such as `def method(self) -> Self` correctly.

The fix here is to treat implicit-self more like explicit-Self,
initially creating it as non-inferable and then using the mark-inferable
transform on it. This is less efficient, but restores the invariant that
all typevars in a given generic context are transformed together, or
not, fixing the bug.

In the improved-constraint-solver work, the separation of typevars into
"inferable" and "non-inferable" is expected to disappear, along with the
mark-inferable transform, which would render both this bug and the fix
moot. So this fix is really just temporary until that lands.

There is a performance regression, but not a huge one: 1-2% on most
projects, 5% on one outlier. This seems acceptable, given that it should
be fully recovered by removing the mark-inferable transform.

## Test Plan

Added mdtests that failed before this change.
2025-10-08 01:38:24 +00:00
Alex Waygood ff386b4797
[ty] Improve diagnostics for bad `@overload` definitions (#20745) 2025-10-07 21:52:57 +00:00
Douglas Creager 416e956fe0
[ty] Infer better specializations of unions with `None` (etc) (#20749)
This PR adds a specialization inference special case that lets us handle
the following examples better:

```py
def f[T](t: T | None) -> T: ...
def g[T](t: T | int | None) -> T | int: ...

def _(x: str | None):
    reveal_type(f(x))  # revealed: str (previously str | None)

def _(y: str | int | None):
    reveal_type(g(x))  # revealed: str | int (previously str | int | None)
```

We already have a special case for when the formal is a union where one
element is a typevar, but it maps the entire actual type to the typevar
(as you can see in the "previously" results above).

The new special case kicks in when the actual is also a union. Now, we
filter out any actual union elements that are already subtypes of the
formal, and only bind whatever types remain to the typevar. (The `|
None` pattern appears quite often in the ecosystem results, but it's
more general and works with any number of non-typevar union elements.)

The new constraint solver should handle this case as well, but it's
worth adding this heuristic now with the old solver because it
eliminates some false positives from the ecosystem report, and makes the
ecosystem report less noisy on the other constraint solver PRs.
2025-10-07 13:33:42 -04:00
Brent Westbrook 88c0ce3e38
Update default and latest Python versions for 3.14 (#20725)
Summary
--

Closes #19467 and also removes the warning about using Python 3.14
without
preview enabled.

I also bumped `PythonVersion::default` to 3.9 because it reaches EOL
this month,
but we could also defer that for now if we wanted.

The first three commits are related to the `latest` bump to 3.14; the
fourth commit
bumps the default to 3.10.

Note that this PR also bumps the default Python version for ty to 3.10
because
there was a test asserting that it stays in sync with
`ast::PythonVersion`.

Test Plan
--

Existing tests

I spot-checked the ecosystem report, and I believe these are all
expected. Inbits doesn't specify a target Python version, so I guess
we're applying the default. UP007, UP035, and UP045 all use the new
default value to emit new diagnostics.
2025-10-07 12:23:11 -04:00
David Peter 23ebfe7777
[ty] Fix tiny mistake in protocol tests (#20743) 2025-10-07 11:58:35 +00:00
Ibraheem Ahmed 2ce3aba458
[ty] Use annotated parameters as type context (#20635)
## Summary

Use the type annotation of function parameters as bidirectional type
context when inferring the argument expression. For example, the
following example now type-checks:

```py
class TD(TypedDict):
    x: int

def f(_: TD): ...

f({ "x": 1 })
```

Part of https://github.com/astral-sh/ty/issues/168.
2025-10-03 17:14:51 -04:00
Alex Waygood c91b457044
[ty] Introduce `TypeRelation::Redundancy` (#20602)
## Summary

The union `T | U` can be validly simplified to `U` iff:
1. `T` is a subtype of `U` OR
2. `T` is equivalent to `U` OR
3. `U` is a union and contains a type that is equivalent to `T` OR
4. `T` is an intersection and contains a type that is equivalent to `U`

(In practice, the only situation in which 2, 3 or 4 would be true when
(1) was not true would be if `T` or `U` is a dynamic type.)

Currently we achieve these simplifications in the union builder by doing
something along the lines of `t.is_subtype_of(db, u) ||
t.is_equivalent_to_(db, u) ||
t.into_intersection().is_some_and(|intersection|
intersection.positive(db).contains(&u)) ||
u.into_union().is_some_and(|union| union.elements(db).contains(&t))`.
But this is both slow and misses some cases (it doesn't simplify the
union `Any | (Unknown & ~None)` to `Any`, for example). We can improve
the consistency and performance of our union simplifications by adding a
third type relation that sits in between `TypeRelation::Subtyping` and
`TypeRelation::Assignability`: `TypeRelation::UnionSimplification`.

This change leads to simpler, more user-friendly types due to the more
consistent simplification. It also lead to a pretty huge performance
improvement!

## Test Plan

Existing tests, plus some new ones.
2025-10-03 18:35:30 +01:00
Dhruv Manilawala 4e94b22815
[ty] Support single-starred argument for overload call (#20223)
## Summary

closes: https://github.com/astral-sh/ty/issues/247

This PR adds support for variadic arguments to overload call evaluation.

This basically boils down to making sure that the overloads are not
filtered out incorrectly during the step 5 in the overload call
evaluation algorithm. For context, the step 5 tries to filter out the
remaining overloads after finding an overload where the materialization
of argument types are assignable to the parameter types.

The issue with the previous implementation was that it wouldn't unpack
the variadic argument and wouldn't consider the many-to-one (multiple
arguments mapping to a single variadic parameter) correctly. This PR
fixes that.

## Test Plan

Update existing test cases and resolve the TODOs.
2025-10-02 10:41:56 -04:00
Alex Waygood 0639da2552
[ty] `~T` should never be assignable to `T` (#20606)
## Summary

Currently we do not emit an error on this code:

```py
from ty_extensions import Not

def f[T](x: T, y: Not[T]) -> T:
    x = y
    return x
```

But we should do! `~T` should never be assignable to `T`.

This fixes a small regression introduced in
14fe1228e7 (diff-8049ab5af787dba29daa389bbe2b691560c15461ef536f122b1beab112a4b48aR1443-R1446),
where a branch that previously returned `false` was replaced with a
branch that returns `C::always_satisfiable` -- the opposite of what it
used to be! The regression occurred because we didn't have any tests for
this -- so I added some tests in this PR that fail on `main`. I only
spotted the problem because I was going through the code of
`has_relation_to_impl` with a fine toothcomb for
https://github.com/astral-sh/ruff/pull/20602 😄
2025-10-02 07:52:47 +01:00
David Peter 71d711257a
[ty] No union with `Unknown` for module-global symbols (#20664)
## Summary

Quoting from the newly added comment:

Module-level globals can be mutated externally. A `MY_CONSTANT = 1`
global might be changed to `"some string"` from code outside of the
module that we're looking at, and so from a gradual-guarantee
perspective, it makes sense to infer a type of `Literal[1] | Unknown`
for global symbols. This allows the code that does the mutation to type
check correctly, and for code that uses the global, it accurately
reflects the lack of knowledge about the type.

External modifications (or modifications through `global` statements)
that would require a wider type are relatively rare. From a practical
perspective, we can therefore achieve a better user experience by
trusting the inferred type. Users who need the external mutation to work
can always annotate the global with the wider type. And everyone else
benefits from more precise type inference.

I initially implemented this by applying literal promotion to the type
of the unannotated module globals (as suggested in
https://github.com/astral-sh/ty/issues/1069), but the ecosystem impact
showed a lot of problems (https://github.com/astral-sh/ruff/pull/20643).
I fixed/patched some of these problems, but this PR seems like a good
first step, and it seems sensible to apply the literal promotion change
in a second step that can be evaluated separately.

closes https://github.com/astral-sh/ty/issues/1069

## Ecosystem impact

This seems like an (unexpectedly large) net positive with 650 fewer
diagnostics overall.. even though this change will certainly catch more
true positives.

* There are 666 removed `type-assertion-failure` diagnostics, where we
were previously used the correct type already, but removing the
`Unknown` now leads to an "exact" match.
* 1464 of the 1805 total new diagnostics are `unresolved-attribute`
errors, most (1365) of which were previously
`possibly-missing-attribute` errors. So they could also be counted as
"changed" diagnostics.
* For code that uses constants like
  ```py
  IS_PYTHON_AT_LEAST_3_10 = sys.version_info >= (3, 10)
  ```
where we would have previously inferred a type of `Literal[True/False] |
Unknown`, removing the `Unknown` now allows us to do reachability
analysis on branches that use these constants, and so we get a lot of
favorable ecosystem changes because of that.
* There is code like the following, where we previously emitted
`conflicting-argument-forms` diagnostics on calls to the aliased
`assert_type`, because its type was `Unknown | def …` (and the call to
`Unknown` "used" the type form argument in a non type-form way):
  ```py
  if sys.version_info >= (3, 11):
      import typing
  
      assert_type = typing.assert_type
  else:
      import typing_extensions
  
      assert_type = typing_extensions.assert_type
  ```
* ~100 new `invalid-argument-type` false positives, due to missing
`**kwargs` support (https://github.com/astral-sh/ty/issues/247)

## Typing conformance

```diff
+protocols_modules.py:25:1: error[invalid-assignment] Object of type `<module '_protocols_modules1'>` is not assignable to `Options1`
```

This diagnostic should apparently not be there, but it looks like we
also fail other tests in that file, so it seems to be a limitation that
was previously hidden by `Unknown` somehow.

## Test Plan

Updated tests and relatively thorough ecosystem analysis.
2025-10-01 16:40:30 +02:00
David Peter 56d630e303
[ty] Enums: allow multiple aliases to point to the same member (#20669)
## Summary

closes https://github.com/astral-sh/ty/issues/1293

## Test Plan

Regression test
2025-10-01 15:51:53 +02:00
David Peter 963bc8c228
[ty] Reformulation of public symbol inference test suite (#20667)
## Summary

Reformulation of the public symbol type inference test suite to use
class scopes instead of module scopes. This is in preparation for an
upcoming change to module-global scopes (#20664).

## Test Plan

Updated tests
2025-10-01 14:26:17 +02:00
Alex Waygood 20eb5b5b35
[ty] Fix subtyping of invariant generics specialized with `Any` (#20650) 2025-10-01 10:05:54 +00:00
github-actions[bot] d9473a2fcf
[ty] Sync vendored typeshed stubs (#20658)
---------

Co-authored-by: typeshedbot <>
Co-authored-by: David Peter <mail@david-peter.de>
2025-10-01 10:11:48 +02:00
Douglas Creager a422716267
[ty] Fix flaky constraint set rendering (#20653)
This doesn't seem to be flaky in the sense of tests failing
non-deterministically, but they are flaky in the sense of unrelated
changes causing testing failures from the clauses of a constraint set
being rendered in different orders. This flakiness is because we're
using Salsa IDs to determine the order in which typevars appear in a
constraint set BDD, and those IDs are assigned non-deterministically.

The fix is ham-fisted but effective: sort the constraints in each
clause, and the clauses in each set, as part of the rendering process.
Constraint sets are only rendered in our test cases, so we don't need to
over-optimize this.
2025-10-01 09:14:35 +02:00
David Peter b483d3b0b9
[ty] Literal promotion refactor (#20646)
## Summary

Not sure if this was the original intention, but it looks to me like the
previous `Type::literal_promotion_type` was more of an implementation
detail for the actual operation of promoting all literals in a
possibly-nested position of a type.

This is not a pure refactor, as I'm technically changing the behavior
for that protocols diagnostic message suggestion.

## Test Plan

New Markdown test
2025-09-30 14:22:36 +02:00
David Peter 130a794c2b
[ty] Add tests for nested generic functions (#20631)
## Summary

Add two simple tests that we recently discussed with @dcreager. They
demonstrate that the `TypeMapping::MarkTypeVarsInferable` operation
really does need to keep track of the binding context.

## Test Plan

Made sure that those tests fail if we create
`TypeMapping::MarkTypeVarsInferable(None)`s everywhere.
2025-09-30 08:44:18 +02:00
David Peter 0092794302
[ty] Use `typing.Self` for the first parameter of instance methods (#20517)
## Summary

Modify the (external) signature of instance methods such that the first
parameter uses `Self` unless it is explicitly annotated. This allows us
to correctly type-check more code, and allows us to infer correct return
types for many functions that return `Self`. For example:

```py
from pathlib import Path
from datetime import datetime, timedelta

reveal_type(Path(".config") / ".ty")  # now Path, previously Unknown

def _(dt: datetime, delta: timedelta):
    reveal_type(dt - delta)  # now datetime, previously Unknown
```

part of https://github.com/astral-sh/ty/issues/159

## Performance

I ran benchmarks locally on `attrs`, `freqtrade` and `colour`, the
projects with the largest regressions on CodSpeed. I see much smaller
effects locally, but can definitely reproduce the regression on `attrs`.
From looking at the profiling results (on Codspeed), it seems that we
simply do more type inference work, which seems plausible, given that we
now understand much more return types (of many stdlib functions). In
particular, whenever a function uses an implicit `self` and returns
`Self` (without mentioning `Self` anywhere else in its signature), we
will now infer the correct type, whereas we would previously return
`Unknown`. This also means that we need to invoke the generics solver in
more cases. Comparing half a million lines of log output on attrs, I can
see that we do 5% more "work" (number of lines in the log), and have a
lot more `apply_specialization` events (7108 vs 4304). On freqtrade, I
see similar numbers for `apply_specialization` (11360 vs 5138 calls).
Given these results, I'm not sure if it's generally worth doing more
performance work, especially since none of the code modifications
themselves seem to be likely candidates for regressions.

| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
|:---|---:|---:|---:|---:|
| `./ty_main check /home/shark/ecosystem/attrs` | 92.6 ± 3.6 | 85.9 |
102.6 | 1.00 |
| `./ty_self check /home/shark/ecosystem/attrs` | 101.7 ± 3.5 | 96.9 |
113.8 | 1.10 ± 0.06 |

| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
|:---|---:|---:|---:|---:|
| `./ty_main check /home/shark/ecosystem/freqtrade` | 599.0 ± 20.2 |
568.2 | 627.5 | 1.00 |
| `./ty_self check /home/shark/ecosystem/freqtrade` | 607.9 ± 11.5 |
594.9 | 626.4 | 1.01 ± 0.04 |

| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
|:---|---:|---:|---:|---:|
| `./ty_main check /home/shark/ecosystem/colour` | 423.9 ± 17.9 | 394.6
| 447.4 | 1.00 |
| `./ty_self check /home/shark/ecosystem/colour` | 426.9 ± 24.9 | 373.8
| 456.6 | 1.01 ± 0.07 |

## Test Plan

New Markdown tests

## Ecosystem report

* apprise: ~300 new diagnostics related to problematic stubs in apprise
😩
* attrs: a new true positive, since [this
function](4e2c89c823/tests/test_make.py (L2135))
is missing a `@staticmethod`?
* Some legitimate true positives
* sympy: lots of new `invalid-operator` false positives in [matrix
multiplication](cf9f4b6805/sympy/matrices/matrixbase.py (L3267-L3269))
due to our limited understanding of [generic `Callable[[Callable[[T1,
T2], T3]], Callable[[T1, T2], T3]]` "identity"
types](cf9f4b6805/sympy/core/decorators.py (L83-L84))
of decorators. This is not related to type-of-self.

## Typing conformance results

The changes are all correct, except for
```diff
+generics_self_usage.py:50:5: error[invalid-assignment] Object of type `def foo(self) -> int` is not assignable to `(typing.Self, /) -> int`
```
which is related to an assignability problem involving type variables on
both sides:
```py
class CallableAttribute:
    def foo(self) -> int:
        return 0

    bar: Callable[[Self], int] = foo  # <- we currently error on this assignment
```

---------

Co-authored-by: Shaygan Hooshyari <sh.hooshyari@gmail.com>
2025-09-29 21:08:08 +02:00
Alex Waygood 1cf19732b9
[ty] Use fully qualified names to distinguish ambiguous protocols in diagnostics (#20627) 2025-09-29 12:02:07 +00:00
Alex Waygood 3f640dacd4
[ty] Improve disambiguation of class names in diagnostics (#20603) 2025-09-29 11:43:11 +01:00
Alex Waygood 6b3c493cff
[ty] Use `Top` materializations for `TypeIs` special form (#20591) 2025-09-26 17:24:43 +00:00
Alex Waygood e4de179cdd
[ty] Simplify `Any | (Any & T)` to `Any` (#20593) 2025-09-26 17:00:10 +01:00
David Peter 3932f7c849
[ty] Fix subtyping for dynamic specializations (#20592)
## Summary

Fixes a bug observed by @AlexWaygood where `C[Any] <: C[object]` should
hold for a class that is covariant in its type parameter (and similar
subtyping relations involving dynamic types for other variance
configurations).

## Test Plan

New and updated Markdown tests
2025-09-26 15:05:03 +02:00
Alex Waygood 2af8c53110
[ty] Add more tests for subtyping/assignability between two protocol types (#20573) 2025-09-26 12:07:57 +01:00
Douglas Creager 02ebb2ee61
[ty] Change to BDD representation for constraint sets (#20533)
While working on #20093, I kept running into test failures due to
constraint sets not simplifying as much as they could, and therefore not
being easily testable against "always true" and "always false".

This PR updates our constraint set representation to use BDDs. Because
BDDs are reduced and ordered, they are canonical — equivalent boolean
formulas are represented by the same interned BDD node.

That said, there is a wrinkle, in that the "variables" that we use in
these BDDs — the individual constraints like `Lower ≤ T ≤ Upper` are not
always independent of each other.

As an example, given types `A ≤ B ≤ C ≤ D` and a typevar `T`, the
constraints `A ≤ T ≤ C` and `B ≤ T ≤ D` "overlap" — their intersection
is non-empty. So we should be able to simplify

```
(A ≤ T ≤ C) ∧ (B ≤ T ≤ D) == (B ≤ T ≤ C)
```

That's not a simplification that the BDD structure can perform itself,
since those three constraints are modeled as separate BDD variables, and
are therefore "opaque" to the BDD algorithms.

That means we need to perform this kind of simplification ourselves. We
look at pairs of constraints that appear in a BDD and see if they can be
simplified relative to each other, and if so, replace the pair with the
simplification. A large part of the toil of getting this PR to work was
identifying all of those patterns and getting that substitution logic
correct.

With this new representation, all existing tests pass, as well as some
new ones that represent test failures that were occuring on #20093.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-09-25 21:55:35 -04:00
Dhruv Manilawala 35ed55ec8c
[ty] Filter overloads using variadic parameters (#20547)
## Summary

Closes: https://github.com/astral-sh/ty/issues/551

This PR adds support for step 4 of the overload call evaluation
algorithm which states that:

> If the argument list is compatible with two or more overloads,
determine whether one or more of the overloads has a variadic parameter
(either `*args` or `**kwargs`) that maps to a corresponding argument
that supplies an indeterminate number of positional or keyword
arguments. If so, eliminate overloads that do not have a variadic
parameter.

And, with that, the overload call evaluation algorithm has been
implemented completely end to end as stated in the typing spec.

## Test Plan

Expand the overload call test suite.
2025-09-25 14:58:00 +00:00
David Peter efbb80f747
[ty] Remove hack in protocol satisfiability check (#20568)
## Summary

This removes a hack in the protocol satisfiability check that was
previously needed to work around missing assignability-modeling of
inferable type variables. Assignability of type variables is not
implemented fully, but some recent changes allow us to remove that hack
with limited impact on the ecosystem (and the test suite). The change in
the typing conformance test is favorable.

## Test Plan

* Adapted Markdown tests
* Made sure that this change works in combination with
https://github.com/astral-sh/ruff/pull/20517
2025-09-25 13:35:47 +02:00
Alex Waygood 21be94ac33
[ty] Explicitly test assignability/subtyping between unions of nominal types and protocols with method members (#20557) 2025-09-25 09:21:29 +00:00
Alex Waygood b7d5dc98c1
[ty] Add tests for interactions of `@classmethod`, `@staticmethod`, and protocol method members (#20555) 2025-09-25 10:14:53 +01:00
Dhruv Manilawala e1bb74b25a
[ty] Match variadic argument to variadic parameter (#20511)
## Summary

Closes: https://github.com/astral-sh/ty/issues/1236

This PR fixes a bug where the variadic argument wouldn't match against
the variadic parameter in certain scenarios.

This was happening because I didn't realize that the `all_elements`
iterator wouldn't keep on returning the variable element (which is
correct, I just didn't realize it back then).

I don't think we can use the `resize` method here because we don't know
how many parameters this variadic argument is matching against as this
is where the actual parameter matching occurs.

## Test Plan

Expand test cases to consider a few more combinations of arguments and
parameters which are variadic.
2025-09-25 07:51:56 +00:00
Aria Desires edeb45804e
[ty] fallback to resolve_real_module in file_to_module (#20461)
This is a naive(?) implementation of the approach @MichaReiser
originally suggested to me in https://github.com/astral-sh/ty/issues/869

Fixes https://github.com/astral-sh/ty/issues/869
Fixes https://github.com/astral-sh/ty/issues/1195
2025-09-24 21:15:35 -04:00
Ibraheem Ahmed bea92c8229
[ty] More precise type inference for dictionary literals (#20523)
## Summary

Extends https://github.com/astral-sh/ruff/pull/20360 to dictionary
literals. This also improves our `TypeDict` support by passing through
nested type context.
2025-09-24 18:12:00 -04:00
David Peter fcc76bb7b2
[ty] Todo-types for `os.fdopen`, `NamedTemporaryFile`, and `Path.open` (#20549)
## Summary

This applies the trick that we use for `builtins.open` to similar
functions that have the same problem. The reason is that the problem
would otherwise become even more pronounced once we add understanding of
the implicit type of `self` parameters, because then something like
`(base_path / "test.bin").open("rb")` also leads to a wrong return type
and can result in false positives.

## Test Plan

New Markdown tests
2025-09-24 15:43:58 +02:00
Shunsuke Shibayama 722f1a7d7a
[ty] fix stack overflow when comparing recursive `NamedTuple` types with `is_disjoint_from` (#20538)
## Summary

I found this bug while working on #20528.
The minimum reproducible code is:

```python
from __future__ import annotations

from typing import NamedTuple
from ty_extensions import is_disjoint_from, static_assert

class Path(NamedTuple):
    prev: Path | None
    key: str

static_assert(not is_disjoint_from(Path, Path))
```

A stack overflow occurs when a nominal instance type inherits from
`NamedTuple` and is defined recursively.
This PR fixes this bug.

## Test Plan

mdtest updated
2025-09-23 19:29:03 +02:00
Renkai Ge bf38e69870
[ty] Rename "possibly unbound" diagnostics to "possibly missing" (#20492)
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
2025-09-23 14:26:55 +00:00
fgiacome 4ed8c65d29
[ty] Add positional-only-parameter-as-kwarg error (#20495) 2025-09-23 15:10:45 +01:00
Dan Parizher 346842f003
[`pyflakes`] Fix false positives for `__annotate__` (Py3.14+) and `__warningregistry__` (`F821`) (#20154)
## Summary

Fixes #19970

---------

Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
2025-09-23 08:16:00 -04:00
David Peter 742f8a4ee6
[ty] Use `C[T]` instead of `C[Unknown]` for the upper bound of `Self` (#20479)
### Summary

This PR includes two changes, both of which are necessary to resolve
https://github.com/astral-sh/ty/issues/1196:

* For a generic class `C[T]`, we previously used `C[Unknown]` as the
upper bound of the `Self` type variable. There were two problems with
this. For one, when `Self` appeared in contravariant position, we would
materialize its upper bound to `Bottom[C[Unknown]]` (which might
simplify to `C[Never]` if `C` is covariant in `T`) when accessing
methods on `Top[C[Unknown]]`. This would result in `invalid-argument`
errors on the `self` parameter. Also, using an upper bound of
`C[Unknown]` would mean that inside methods, references to `T` would be
treated as `Unknown`. This could lead to false negatives. To fix this,
we now use `C[T]` (with a "nested" typevar) as the upper bound for
`Self` on `C[T]`.
* In order to make this work, we needed to allow assignability/subtyping
of inferable typevars to other types, since we now check assignability
of e.g. `C[int]` to `C[T]` (when checking assignability to the upper
bound of `Self`) when calling an instance-method on `C[int]` whose
`self` parameter is annotated as `self: Self` (or implicitly `Self`,
following https://github.com/astral-sh/ruff/pull/18007).

closes https://github.com/astral-sh/ty/issues/1196
closes https://github.com/astral-sh/ty/issues/1208


### Test Plan

Regression tests for both issues.
2025-09-23 14:02:25 +02:00
justin ef4df34652
[ty] implement `auto()` for `StrEnum` (#20524)
## Summary
see discussion here:
https://github.com/astral-sh/ty/issues/876#issuecomment-3310130167

https://docs.python.org/3/library/enum.html#enum.StrEnum

> Note Using
[auto](https://docs.python.org/3/library/enum.html#enum.auto) with
[StrEnum](https://docs.python.org/3/library/enum.html#enum.StrEnum)
results in the lower-cased member name as the value.

## Test Plan
- new mdtest
- also, added a test to assert the (already correct) behavior for
`IntEnum`

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-09-23 12:22:59 +02:00
Matthew Mckee 68ae9c8a15
[ty] Fix class literal subtyping with object fallback (#20521)
## Summary

@ibraheemdev notes this example failed

```py
from typing import Callable

class X:
    ...

def f(callable: Callable[[], X]) -> X:
    return callable()

x = f(X)
```

Resolves https://github.com/astral-sh/ty/issues/1210

The issue was that we set the `Self` to the class type instead of the
instance type of the class.

## Test Plan

Fix tests in `is_subtype_of.md`
2025-09-22 17:26:25 -07:00
Alex Waygood f1aacd0f2c
[ty] The runtime object `typing.Protocol` is an instance of `_ProtocolMeta` (#20488)
## Summary

Fixes https://github.com/astral-sh/ty/issues/1218.

This bug doesn't currently cause us any real-world issues, because we
don't yet understand the signatures typeshed gives us for `isinstance()`
and `issubclass()` (typeshed's annotations there use PEP-613 type
aliases). #20107 demonstrates that this will start causing us issues as
soon as we add support for PEP-613 aliases, however, so it makes sense
to fix it now.

## Test Plan

Added mdtests
2025-09-22 08:29:03 +01:00
Ibraheem Ahmed 12086dfa69 re-infer RHS of annotated assignments in isolation for assignability diagnostics 2025-09-19 17:00:37 -04:00
Ibraheem Ahmed 5f294f9f2e use type context for inference of generic function calls 2025-09-19 17:00:37 -04:00
Dhruv Manilawala 902b0b4ce9
[ty] Add support for `**kwargs` (#20430)
## Summary

This PR adds support for unpacking `**kwargs` argument.

This can be matched against any standard (positional or keyword),
keyword-only, or keyword variadic parameter that haven't been matched
yet.

This PR also takes care of special casing `TypedDict` because the key
names and the corresponding value type is known, so we can be more
precise in our matching and type checking step. In the future, this
special casing would be extended to include `ParamSpec` as well.

Part of astral-sh/ty#247

## Test Plan

Add test cases for various scenarios.
2025-09-19 05:00:30 +00:00
Eric Mark Martin 2502ff7638
[ty] Make TypeIs invariant in its type argument (#20428)
## Summary

What it says on the tin. See the [typing
spec](https://docs.python.org/3/library/typing.html#typing.TypeIs) for
justification.

## Test Plan

Add more tests to PEP 695 `variance.md` suite.
2025-09-18 07:53:13 -07:00
Ibraheem Ahmed e84d523bcf
[ty] Infer more precise types for collection literals (#20360)
## Summary

Part of https://github.com/astral-sh/ty/issues/168. Infer more precise types for collection literals (currently, only `list` and `set`). For example,

```py
x = [1, 2, 3] # revealed: list[Unknown | int]
y: list[int] = [1, 2, 3] # revealed: list[int]
```

This could easily be extended to `dict` literals, but I am intentionally limiting scope for now.
2025-09-17 18:51:50 -04:00
Shaygan Hooshyari 05622ae757
[ty] Bind Self typevar to method context (#20366)
Fixes: https://github.com/astral-sh/ty/issues/1173

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## Summary

This PR will change the logic of binding Self type variables to bind
self to the immediate function that it's used on.
Since we are binding `self` to methods and not the class itself we need
to ensure that we bind self consistently.

The fix is to traverse scopes containing the self and find the first
function inside a class and use that function to bind the typevar for
self.

If no such scope is found we fallback to the normal behavior. Using Self
outside of a class scope is not legal anyway.

## Test Plan

Added a new mdtest.

Checked the diagnostics that are not emitted anymore in [primer
results](https://github.com/astral-sh/ruff/pull/20366#issuecomment-3289411424).
It looks good altough I don't completely understand what was wrong
before.

---------

Co-authored-by: Douglas Creager <dcreager@dcreager.net>
2025-09-17 14:58:54 -04:00
Carl Meyer 7e464b8150
[ty] move graphql-core to good.txt (#20447)
## Summary

With https://github.com/astral-sh/ruff/pull/20446, graphql-core now
checks without error; we can move it to `good.txt`.

## Test Plan

CI
2025-09-17 10:09:32 +02:00
David Peter ffd650e5fd
[ty] Update mypy_primer (#20433)
## Summary

Revert the materialize-changes, see
https://github.com/hauntsaninja/mypy_primer/pull/208

## Test Plan

CI
2025-09-17 09:51:48 +02:00
Carl Meyer 99ec4d2c69
[ty] detect cycles in binary comparison inference (#20446)
## Summary

Catch infinite recursion in binary-compare inference.

Fixes the stack overflow in `graphql-core` in mypy-primer.

## Test Plan

Added two tests that stack-overflowed before this PR.
2025-09-17 09:45:25 +02:00
justin 9f0b942b9e
[ty] infer `name` and `value` for enum members (#20311)
## summary
- this pr implements the following attributes for `Enum` members:
  - `name`
  - `_name_`
  - `value`
  - `_value_`
- adds a TODO test for `my_enum_class_instance.name`
- only implements if the instance is a subclass of `Enum` re: this
[comment](https://github.com/astral-sh/ruff/pull/19481#issuecomment-3103460307)
and existing
[test](c34449ed7c/crates/ty_python_semantic/resources/mdtest/enums.md?plain=1#L625)

### pointers
- https://github.com/astral-sh/ty/issues/876
- https://typing.python.org/en/latest/spec/enums.html#enum-definition
- https://github.com/astral-sh/ruff/pull/19481#issuecomment-3103460307

## test plan
- mdtests
- triaged conformance diffs here:
https://diffswarm.dev/d-01k531ag4nee3xmdeq4f3j66pb
- triaged mypy primer diffs here for django-stubs:
https://diffswarm.dev/d-01k5331n13k9yx8tvnxnkeawp3
  - added a TODO test for overriding `.value`
- discord diff seems reasonable

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-09-17 09:36:27 +02:00
Carl Meyer c2fa449954
[ty] support type aliases in binary compares (#20445)
## Summary

Add missing `Type::TypeAlias` clauses to `infer_binary_type_comparison`.

## Test Plan

Added mdtests that failed before.
2025-09-17 09:33:26 +02:00
Carl Meyer 681ad2fd92
[ty] move primer projects to good.txt (#20444)
## Summary

After https://github.com/astral-sh/ruff/pull/20359 we can move all but
three remaining projects over to `good.txt`.

## Test Plan

CI
2025-09-17 09:31:27 +02:00
Carl Meyer d121a76aef
[ty] no more diverging query cycles in type expressions (#20359)
## Summary

Use `Type::Divergent` to short-circuit diverging types in type
expressions. This avoids panicking in a wide variety of cases of
recursive type expressions.

Avoids many panics (but not yet all -- I'll be tracking down the rest)
from https://github.com/astral-sh/ty/issues/256 by falling back to
Divergent. For many of these recursive type aliases, we'd like to
support them properly (i.e. really understand the recursive nature of
the type, not just fall back to Divergent) but that will be future work.

This switches `Type::has_divergent_type` from using `any_over_type` to a
custom set of visit methods, because `any_over_type` visits more than we
need to visit, and exercises some lazy attributes of type, causing
significantly more work. This change means this diff doesn't regress
perf; it even reclaims some of the perf regression from
https://github.com/astral-sh/ruff/pull/20333.

## Test Plan

Added mdtest for recursive type alias that panics on main.

Verified that we can now type-check `packaging` (and projects depending
on it) without panic; this will allow moving a number of mypy-primer
projects from `bad.txt` to `good.txt` in a subsequent PR.
2025-09-16 16:44:11 -07:00
Bhuminjay Soni c3f2187fda
[syntax-errors]: import from * only allowed at module scope (F406) (#20166)
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## Summary

This PR implements F406
https://docs.astral.sh/ruff/rules/undefined-local-with-nested-import-star-usage/
as a semantic syntax error

## Test Plan

I have written inline tests as directed in #17412

---------

Signed-off-by: 11happy <soni5happy@gmail.com>
2025-09-16 15:53:28 -04:00
Douglas Creager 1f46c18921
[ty] More constraint set simplifications via simpler constraint representation (#20423)
Previously, we used a very fine-grained representation for individual
constraints: each constraint was _either_ a range constraint, a
not-equivalent constraint, or an incomparable constraint. These three
pieces are enough to represent all of the "real" constraints we need to
create — range constraints and their negation.

However, it meant that we weren't picking up as many chances to simplify
constraint sets as we could. Our simplification logic depends on being
able to look at _pairs_ of constraints or clauses to see if they
simplify relative to each other. With our fine-grained representation,
we could easily encounter situations that we should have been able to
simplify, but that would require looking at three or more individual
constraints.

For instance, negating a range constraint would produce:

```
¬(Base ≤ T ≤ Super) = ((T ≤ Base) ∧ (T ≠ Base)) ∨ (T ≁ Base) ∨
                      ((Super ≤ T) ∧ (T ≠ Super)) ∨ (T ≁ Super)
```

That is, `T` must be (strictly) less than `Base`, (strictly) greater
than `Super`, or incomparable to either.

If we tried to union those back together, we should get `always`, since
`x ∨ ¬x` should always be true, no matter what `x` is. But instead we
would get:

```
(Base ≤ T ≤ Super) ∨ ((T ≤ Base) ∧ (T ≠ Base)) ∨ (T ≁ Base) ∨ ((Super ≤ T) ∧ (T ≠
 Super)) ∨ (T ≁ Super)
```

Nothing would simplify relative to each other, because we'd have to look
at all five union elements to see that together they do in fact combine
to `always`.

The fine-grained representation was nice, because it made it easier to
[work out the math](https://dcreager.net/theory/constraints/) for
intersections and unions of each kind of constraint. But being able to
simplify is more important, since the example above comes up immediately
in #20093 when trying to handle constrained typevars.

The fix in this PR is to go back to a more coarse-grained
representation, where each individual constraint consists of a positive
range (which might be `always` / `Never ≤ T ≤ object`), and zero or more
negative ranges. The intuition is to think of a constraint as a region
of the type space (representable as a range) with zero or more "holes"
removed from it.

With this representation, negating a range constraint produces:

```
¬(Base ≤ T ≤ Super) = (always ∧ ¬(Base ≤ T ≤ Super))
```

(That looks trivial, because it is! We just move the positive range to
the negative side.)

The math is not that much harder than before, because there are only
three combinations to consider (each for intersection and union) —
though the fact that there can be multiple holes in a constraint does
require some nested loops. But the mdtest suite gives me confidence that
this is not introducing any new issues, and it definitely removes a
troublesome TODO.

(As an aside, this change also means that we are back to having each
clause contain no more than one individual constraint for any typevar.
This turned out to be important, because part of our simplification
logic was also depending on that!)

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-09-16 10:05:01 -04:00
David Peter 25cbf38a47
[ty] Patch `Self` for fallback-methods on `NamedTuple`s and `TypedDict`s (#20328)
## Summary

We use classes like
[`_typeshed._type_checker_internals.NamedTupleFallback`](d9c76e1d9f/stdlib/_typeshed/_type_checker_internals.pyi (L54-L75))
to tack on additional attributes/methods to instances of user-defined
`NamedTuple`s (or `TypedDict`s), even though these classes are not
present in the MRO of those types.

The problem is that those classes use implicit and explicit `Self`
annotations which refer to `NamedTupleFallback` itself, instead of to
the actual type that we're adding those methods to:
```py
class NamedTupleFallback(tuple[Any, ...]):
    # […]
    def _replace(self, **kwargs: Any) -> typing_extensions.Self: ...
```

In effect, when we access `_replace` on an instance of a custom
`NamedTuple` instance, its `self` parameter and return type refer to the
wrong `Self`. This leads to incorrect *"Argument to bound method
`_replace` is incorrect: Argument type `Person` does not satisfy upper
bound `NamedTupleFallback` of type variable `Self`"* errors on #18007.
It would also lead to similar errors on `TypedDict`s, if they would
already implement assignability properly.


## Test Plan

I applied the following patch to typeshed and verified that no errors
appear anymore.

<details>

```diff
diff --git a/crates/ty_vendored/vendor/typeshed/stdlib/_typeshed/_type_checker_internals.pyi b/crates/ty_vendored/vendor/typeshed/stdlib/_typeshed/_type_checker_internals.pyi
index feb22aae00..8e41034f19 100644
--- a/crates/ty_vendored/vendor/typeshed/stdlib/_typeshed/_type_checker_internals.pyi
+++ b/crates/ty_vendored/vendor/typeshed/stdlib/_typeshed/_type_checker_internals.pyi
@@ -29,27 +29,27 @@ class TypedDictFallback(Mapping[str, object], metaclass=ABCMeta):
         __readonly_keys__: ClassVar[frozenset[str]]
         __mutable_keys__: ClassVar[frozenset[str]]
 
-    def copy(self) -> typing_extensions.Self: ...
+    def copy(self: typing_extensions.Self) -> typing_extensions.Self: ...
     # Using Never so that only calls using mypy plugin hook that specialize the signature
     # can go through.
-    def setdefault(self, k: Never, default: object) -> object: ...
+    def setdefault(self: typing_extensions.Self, k: Never, default: object) -> object: ...
     # Mypy plugin hook for 'pop' expects that 'default' has a type variable type.
-    def pop(self, k: Never, default: _T = ...) -> object: ...  # pyright: ignore[reportInvalidTypeVarUse]
-    def update(self, m: typing_extensions.Self, /) -> None: ...
-    def __delitem__(self, k: Never) -> None: ...
-    def items(self) -> dict_items[str, object]: ...
-    def keys(self) -> dict_keys[str, object]: ...
-    def values(self) -> dict_values[str, object]: ...
+    def pop(self: typing_extensions.Self, k: Never, default: _T = ...) -> object: ...  # pyright: ignore[reportInvalidTypeVarUse]
+    def update(self: typing_extensions.Self, m: typing_extensions.Self, /) -> None: ...
+    def __delitem__(self: typing_extensions.Self, k: Never) -> None: ...
+    def items(self: typing_extensions.Self) -> dict_items[str, object]: ...
+    def keys(self: typing_extensions.Self) -> dict_keys[str, object]: ...
+    def values(self: typing_extensions.Self) -> dict_values[str, object]: ...
     @overload
-    def __or__(self, value: typing_extensions.Self, /) -> typing_extensions.Self: ...
+    def __or__(self: typing_extensions.Self, value: typing_extensions.Self, /) -> typing_extensions.Self: ...
     @overload
-    def __or__(self, value: dict[str, Any], /) -> dict[str, object]: ...
+    def __or__(self: typing_extensions.Self, value: dict[str, Any], /) -> dict[str, object]: ...
     @overload
-    def __ror__(self, value: typing_extensions.Self, /) -> typing_extensions.Self: ...
+    def __ror__(self: typing_extensions.Self, value: typing_extensions.Self, /) -> typing_extensions.Self: ...
     @overload
-    def __ror__(self, value: dict[str, Any], /) -> dict[str, object]: ...
+    def __ror__(self: typing_extensions.Self, value: dict[str, Any], /) -> dict[str, object]: ...
     # supposedly incompatible definitions of __or__ and __ior__
-    def __ior__(self, value: typing_extensions.Self, /) -> typing_extensions.Self: ...  # type: ignore[misc]
+    def __ior__(self: typing_extensions.Self, value: typing_extensions.Self, /) -> typing_extensions.Self: ...  # type: ignore[misc]
 
 # Fallback type providing methods and attributes that appear on all `NamedTuple` types.
 class NamedTupleFallback(tuple[Any, ...]):
@@ -61,18 +61,18 @@ class NamedTupleFallback(tuple[Any, ...]):
         __orig_bases__: ClassVar[tuple[Any, ...]]
 
     @overload
-    def __init__(self, typename: str, fields: Iterable[tuple[str, Any]], /) -> None: ...
+    def __init__(self: typing_extensions.Self, typename: str, fields: Iterable[tuple[str, Any]], /) -> None: ...
     @overload
     @typing_extensions.deprecated(
         "Creating a typing.NamedTuple using keyword arguments is deprecated and support will be removed in Python 3.15"
     )
-    def __init__(self, typename: str, fields: None = None, /, **kwargs: Any) -> None: ...
+    def __init__(self: typing_extensions.Self, typename: str, fields: None = None, /, **kwargs: Any) -> None: ...
     @classmethod
     def _make(cls, iterable: Iterable[Any]) -> typing_extensions.Self: ...
-    def _asdict(self) -> dict[str, Any]: ...
-    def _replace(self, **kwargs: Any) -> typing_extensions.Self: ...
+    def _asdict(self: typing_extensions.Self) -> dict[str, Any]: ...
+    def _replace(self: typing_extensions.Self, **kwargs: Any) -> typing_extensions.Self: ...
     if sys.version_info >= (3, 13):
-        def __replace__(self, **kwargs: Any) -> typing_extensions.Self: ...
+        def __replace__(self: typing_extensions.Self, **kwargs: Any) -> typing_extensions.Self: ...
 
 # Non-default variations to accommodate couroutines, and `AwaitableGenerator` having a 4th type parameter.
 _S = TypeVar("_S")
```

</details>
2025-09-15 16:21:53 +02:00
Alex Waygood 8341da7f63
[ty] Allow annotation expressions to be `ast::Attribute` nodes (#20413)
Fixes https://github.com/astral-sh/ty/issues/1187
2025-09-15 12:06:48 +01:00
Takayuki Maeda 093fa72656
[`ty`] Include `NamedTupleFallback` members in `NamedTuple` instance completions (#20356)
## Summary

Fixes https://github.com/astral-sh/ty/issues/1161

Include `NamedTupleFallback` members in `NamedTuple` instance
completions.

- Augment instance attribute completions when completing on NamedTuple
instances by merging members from
`_typeshed._type_checker_internals.NamedTupleFallback`

## Test Plan

Adds a minimal completion test `namedtuple_fallback_instance_methods`

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-09-15 11:00:03 +02:00
David Peter 02c58f1beb
[ty] Remove 'materialize' from the ecosystem projects (#20412)
## Summary

This project was [recently removed from
mypy_primer](https://github.com/astral-sh/ruff/pull/20378), so we need
to remove it from `good.txt` in order for ecosystem-analyzer to work
correctly.

## Test Plan

Run mypy_primer and ecosystem-analyzer on this branch.
2025-09-15 10:42:35 +02:00
Alex Waygood 1745554809
[ty] Temporary hack to reduce false positives around `builtins.open()` (#20367)
## Summary

https://github.com/astral-sh/ruff/pull/20165 added a lot of false
positives around calls to `builtins.open()`, because our missing support
for PEP-613 type aliases means that we don't understand typeshed's
overloads for `builtins.open()` at all yet, and therefore always select
the first overload. This didn't use to matter very much, but now that we
have a much stricter implementation of protocol assignability/subtyping
it matters a lot, because most of the stdlib functions dealing with I/O
(`pickle`, `marshal`, `io`, `json`, etc.) are annotated in typeshed as
taking in protocols of some kind.

In lieu of full PEP-613 support, which is blocked on various things and
might not land in time for our next alpha release, this PR adds some
temporary special-casing for `builtins.open()` to avoid the false
positives. We just infer `Todo` for anything that isn't meant to match
typeshed's first `open()` overload. This should be easy to rip out again
once we have proper support for PEP-613 type aliases, which hopefully
should be pretty soon!

## Test Plan

Added an mdtest
2025-09-12 22:20:38 +01:00
Alex Waygood 98708976e4
[ty] Fix subtyping/assignability of function- and class-literal types to callback protocols (#20363)
## Summary

Fixes https://github.com/astral-sh/ty/issues/377.

We were treating any function as being assignable to any callback
protocol, because we were trying to figure out a type's `Callable`
supertype by looking up the `__call__` attribute on the type's
meta-type. But a function-literal's meta-type is `types.FunctionType`,
and `types.FunctionType.__call__` is `(...) -> Any`, which is not very
helpful!

While working on this PR, I also realised that assignability between
class-literals and callback protocols was somewhat broken too, so I
fixed that at the same time.

## Test Plan

Added mdtests
2025-09-12 22:20:09 +01:00
Alex Waygood 33b3d44ebd
[ty] Proper assignability/subtyping checks for protocols with method members (#20165) 2025-09-12 10:10:31 +00:00
Dhruv Manilawala bb9be263c7
[ty] Retry parameter matching for argument type expansion (#20153)
## Summary

This PR addresses an issue for a variadic argument when involved in
argument type expansion of overload call evaluation.

The issue is that the expansion of the variadic argument could result in
argument list of different arity. For example, in `*args: tuple[int] |
tuple[int, str]`, the expansion would lead to the variadic argument
being unpacked into 1 and 2 element respectively. This means that the
parameter matching that was performed initially isn't sufficient and
each expanded argument list would need to redo the parameter matching
again.

This is currently done by redoing the parameter matching directly,
maintaining the state of argument forms (and the conflicting forms), and
updating the `Bindings` values if it changes.

Closes: astral-sh/ty#735

## Test Plan

Update existing mdtest.
2025-09-12 08:40:07 +00:00
Alex Waygood 0e3697a643
[ty] Minor fixes to `Protocol` tests (#20347) 2025-09-11 14:42:13 +00:00
Carl Meyer ffd4340dce
[ty] use Type::Divergent to avoid panic in infinitely-nested-tuple implicit attribute (#20333)
## Summary

Use `Type::Divergent` to avoid "too many iterations" panic on an
infinitely-nested tuple in an implicit instance attribute.

The regression here is from checking all tuple elements to see if they
contain a Divergent type. It's 5% on one project, 1% on another, and
zero on the rest. I spent some time looking into eliminating this
regression by tracking a flag on inference results to note if they could
possibly contain any Divergent type, but this doesn't really work --
there are too many different ways a type containing a Divergent type
could enter an inference result. Still thinking about whether there are
other ways to reduce this. One option is if we see certain kinds of
non-atomic types that are commonly expensive to check for Divergent, we
could make `has_divergent_type` a Salsa query on those types.

## Test Plan

Added mdtest.

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-09-11 06:51:22 -07:00
David Peter 59c8fda3f8
[ty] Fix CallableTypeOf[…] for classmethods (#20345)
## Summary

See https://github.com/astral-sh/ruff/pull/20338#discussion_r2337731998

## Test Plan

Regression test.
2025-09-11 10:14:38 +02:00
David Peter cde5e4e343
[ty] Fix `CallableTypeOf[…]` for bound methods (#20338)
## Summary

`CallableTypeOf[bound_method]` would previously bind `self` to the
bound method type itself, instead of binding it to the instance type
stored inside the bound method type.

## Test Plan

Added regression test
2025-09-10 21:13:23 +02:00
Alex Waygood 8a0edf0da8
[ty] Ensure various special-cased builtin functions are understood as assignable to `Callable` (#20331) 2025-09-10 19:03:33 +00:00
Alex Waygood d23cae870e
[ty] Ensure various special-cased bound methods are understood as assignable to `Callable` (#20330) 2025-09-10 19:58:54 +01:00
Douglas Creager 2ac4147435
[ty] Add mdtests that exercise constraint sets (#20319)
This PR adds a new `ty_extensions.ConstraintSet` class, which is used to
expose constraint sets to our mdtest framework. This lets us write a
large collection of unit tests that exercise the invariants and rewrite
rules of our constraint set implementation.

As part of this, `is_assignable_to` and friends are updated to return a
`ConstraintSet` instead of a `bool`, and we implement
`ConstraintSet.__bool__` to return when a constraint set is always
satisfied. That lets us still use
`static_assert(is_assignable_to(...))`, since the assertion will coerce
the constraint set to a bool, and also lets us
`reveal_type(is_assignable_to(...))` to see more detail about
whether/when the two types are assignable. That lets us get rid of
`reveal_when_assignable_to` and friends, since they are now redundant
with the expanded capabilities of `is_assignable_to`.
2025-09-10 13:22:19 -04:00
Alex Waygood ffead90410
[ty] Add more tests for special-cased builtin functions and methods (#20329) 2025-09-10 18:08:32 +01:00
David Peter 65982a1e14
[ty] Use 'unknown' specialization for upper bound on Self (#20325)
## Summary

closes https://github.com/astral-sh/ty/issues/1156

## Test Plan

Added a regression test
2025-09-10 17:00:28 +02:00
David Peter 57d1f7132d
[ty] Simplify unions of enum literals and subtypes thereof (#20324)
## Summary

When adding an enum literal `E = Literal[Color.RED]` to a union which
already contained a subtype of that enum literal(!), we were previously
not simplifying the union correctly. My assumption is that our property
tests didn't catch that earlier, because the only possible non-trivial
subytpe of an enum literal that I can think of is `Any & E`. And in
order for that to be detected by the property tests, it would have to
randomly generate `Any & E | E` and then also compare that with `E` on
the other side (in an equivalence test, or the subtyping-antisymmetry
test).

closes https://github.com/astral-sh/ty/issues/1155

## Test Plan

* Added a regression test.
* I also ran the property tests for a while, but probably not for two
months worth of daily CI runs.
2025-09-10 15:54:06 +02:00
David Peter 2b51ec6531
[ty] Improve specialization-error diagnostics (#20326)
## Summary

Add information about the upper bound or the constraints of the type
variable to the `SpecializationError` diagnostics.
2025-09-10 14:01:23 +02:00
Alex Waygood b85c995927
[ty] `"foo".startswith` is not an instance of `types.MethodWrapperType` (#20317) 2025-09-10 11:14:26 +00:00
Alex Waygood fd7eb1e22f
[ty] Allow protocols to participate in nominal subtyping as well as structural subtyping (#20314) 2025-09-10 11:05:50 +00:00
Alex Waygood 4de7d653bd
[ty] Treat `Hashable`, and similar protocols, equivalently to `object` for subtyping/assignability (#20284) 2025-09-10 11:38:58 +01:00
Alex Waygood bf66178959
[ty] Add tests for protocols with generic method members (#20316) 2025-09-09 16:44:00 +00:00
Renkai Ge 61f906d8e7
[ty] equality narrowing on enums that don't override `__eq__` or `__ne__` (#20285)
Add equality narrowing for enums, if they don't override `__eq__` or `__ne__` in an unsafe way.

Follow-up to PR https://github.com/astral-sh/ruff/pull/20164

Fixes https://github.com/astral-sh/ty/issues/939
2025-09-08 16:56:28 -07:00
Shunsuke Shibayama 08a561fc05
[ty] more precise lazy scope place lookup (#19932)
## Summary

This is a follow-up to https://github.com/astral-sh/ruff/pull/19321.

Now lazy snapshots are updated to take into account new bindings on
every symbol reassignment.

```python
def outer(x: A | None):
    if x is None:
        x = A()

    reveal_type(x)  # revealed: A

    def inner() -> None:
        # lazy snapshot: {x: A}
        reveal_type(x)  # revealed: A
    inner()

def outer() -> None:
    x = None

    x = 1

    def inner() -> None:
        # lazy snapshot: {x: Literal[1]} -> {x: Literal[1, 2]}
        reveal_type(x)  # revealed: Literal[1, 2]
    inner()

    x = 2
```

Closes astral-sh/ty#559.

## Test Plan

Some TODOs in `public_types.md` now work properly.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-09-08 21:08:35 +00:00
Ibraheem Ahmed aa5d665d52
[ty] Add support for generic PEP695 type aliases (#20219)
## Summary

Adds support for generic PEP695 type aliases, e.g.,
```python
type A[T] = T
reveal_type(A[int]) # A[int]
```

Resolves https://github.com/astral-sh/ty/issues/677.
2025-09-08 13:26:21 -07:00
David Peter d55edb3d74
[ty] Support "legacy" `typing.Self` in combination with PEP 695 generic contexts (#20304)
## Summary

Support cases like the following, where we need the generic context to
include both `Self` and `T` (not just `T`):

```py
from typing import Self

class C:
    def method[T](self: Self, arg: T): ...

C().method(1)
```

closes https://github.com/astral-sh/ty/issues/1131

## Test Plan

Added regression test
2025-09-08 16:57:09 +02:00
Alex Waygood deb3d3d150
[ty] Fall back to `object` for attribute access on synthesized protocols (#20286) 2025-09-08 13:04:37 +01:00
justin 08fcf7e106
[ty] initial support for `slots=True` in dataclasses (#20278) 2025-09-07 18:25:35 +01:00
Carl Meyer 2467c4352e
[ty] propagate visitors and constraints through has_relation_in_invariant_position (#20259)
## Summary

The sub-checks for assignability and subtyping of materializations
performed in `has_relation_in_invariant_position` and
`is_subtype_in_invariant_position` need to propagate the
`HasRelationToVisitor`, or we can stack overflow.

A side effect of this change is that we also propagate the
`ConstraintSet` through, rather than using `C::from_bool`, which I think
may also become important for correctness in cases involving type
variables (though it isn't testable yet, since we aren't yet actually
creating constraints other than always-true and always-false.)

## Test Plan

Added mdtest (derived from code found in pydantic) which
stack-overflowed before this PR.

With this change incorporated, pydantic now checks successfully on my
draft PR for PEP 613 TypeAlias support.
2025-09-06 00:17:17 +00:00
Alex Waygood 5d52902e18
[ty] Implement the legacy PEP-484 convention for indicating positional-only parameters (#20248)
Co-authored-by: Carl Meyer <carl@astral.sh>
2025-09-05 17:56:06 +01:00
David Peter fdfb51b595
[ty] Update mypy_primer, add egglog-python project (#20078)
Now that https://github.com/astral-sh/ruff/pull/20263 is merged, we can
update mypy_primer and add the new `egglog-python` project to
`good.txt`. The ecosystem-analyzer run shows that we now add 1,356
diagnostics (where we had over 5,000 previously, due to the unsupported
project layout).
2025-09-05 14:17:07 +02:00
David Peter 8ade6c4eaf
[ty] Add backreferences to TypedDict items in diagnostics (#20262)
## Summary

Add backreferences to the original item declaration in TypedDict
diagnostics.

Thanks to @AlexWaygood for the suggestion.

## Test Plan

Updated snapshots
2025-09-05 12:38:37 +02:00
David Peter 9e45bfa9fd
[ty] Cover full range of annotated assignments (#20261)
## Summary

An annotated assignment `name: annotation` without a right-hand side was
previously not covered by the range returned from
`DefinitionKind::full_range`, because we did expand the range to include
the right-hand side (if there was one), but failed to include the
annotation.

## Test Plan

Updated snapshot tests
2025-09-05 10:12:40 +02:00
David Peter 7509d376eb
[ty] Minor: 'can not' => cannot (#20260) 2025-09-05 09:19:14 +02:00
David Peter a24a4b55ee
[ty] TypedDict: Add support for `typing.ReadOnly` (#20241)
## Summary

Add support for `typing.ReadOnly` as a type qualifier to mark
`TypedDict` fields as being read-only. If you try to mutate them, you
get a new diagnostic:

<img width="787" height="234" alt="image"
src="https://github.com/user-attachments/assets/f62fddf9-4961-4bcd-ad1c-747043ebe5ff"
/>


## Test Plan

* New Markdown tests
* The typing conformance changes are all correct. There are some false
negatives, but those are related to the missing support for the
functional form of `TypedDict`, or to overriding of fields via
inheritance. Both of these topics are tracked in
https://github.com/astral-sh/ty/issues/154
2025-09-04 15:37:42 -07:00