Commit Graph

795 Commits

Author SHA1 Message Date
Carl Meyer c32234cf0d
[ty] support subscripting typing.Literal with a type alias (#21207)
Fixes https://github.com/astral-sh/ty/issues/1368

## Summary

Add support for patterns like this, where a type alias to a literal type
(or union of literal types) is used to subscript `typing.Literal`:

```py
type MyAlias = Literal[1]
def _(x: Literal[MyAlias]): ...
```

This shows up in the ecosystem report for PEP 613 type alias support.

One interesting case is an alias to `bool` or an enum type. `bool` is an
equivalent type to `Literal[True, False]`, which is a union of literal
types. Similarly an enum type `E` is also equivalent to a union of its
member literal types. Since (for explicit type aliases) we infer the RHS
directly as a type expression, this makes it difficult for us to
distinguish between `bool` and `Literal[True, False]`, so we allow
either one to (or an alias to either one) to appear inside `Literal`,
where other type checkers allow only the latter.

I think for implicit type aliases it may be simpler to support only
types derived from actually subscripting `typing.Literal`, though, so I
didn't make a TODO-comment commitment here.

## Test Plan

Added mdtests, including TODO-filled tests for PEP 613 and implicit type
aliases.

### Conformance suite

All changes here are positive -- we now emit errors on lines that should
be errors. This is a side effect of the new implementation, not the
primary purpose of this PR, but it's still a positive change.

### Ecosystem

Eliminates one ecosystem false positive, where a PEP 695 type alias for
a union of literal types is used to subscript `typing.Literal`.
2025-11-02 12:39:55 -05:00
David Peter 73107a083c
[ty] Type inference for comprehensions (#20962)
## Summary

Adds type inference for list/dict/set comprehensions, including
bidirectional inference:

```py
reveal_type({k: v for k, v in [("a", 1), ("b", 2)]})  # dict[Unknown | str, Unknown | int]

squares: list[int | None] = [x for x in range(10)]
reveal_type(squares)  # list[int | None]
```

## Ecosystem impact

I did spot check the changes and most of them seem like known
limitations or true positives. Without proper bidirectional inference,
we saw a lot of false positives.

## Test Plan

New Markdown tests
2025-11-02 14:35:33 +01:00
Alex Waygood a32d5b8dc4
[ty] Improve exhaustiveness analysis for type variables with bounds or constraints (#21172) 2025-10-31 16:51:11 -04:00
David Peter 1734ddfb3e
[ty] Do not promote literals in contravariant positions of generic specializations (#21171)
## Summary

closes https://github.com/astral-sh/ty/issues/1284

supersedes https://github.com/astral-sh/ruff/pull/20950 by @ibraheemdev 

## Test Plan

New regression test
2025-10-31 17:48:34 +01:00
Ibraheem Ahmed ff3a6a8fbd
[ty] Support type context of union attribute assignments (#21170)
## Summary

Turns out this is easy to implement. Resolves
https://github.com/astral-sh/ty/issues/1375.
2025-10-31 12:41:14 -04:00
Carl Meyer 9664474c51
[ty] rollback preferring declared type on invalid TypedDict creation (#21169)
## Summary

Discussion with @ibraheemdev clarified that
https://github.com/astral-sh/ruff/pull/21168 was incorrect. In a case of
failed inference of a dict literal as a `TypedDict`, we should store the
context-less inferred type of the dict literal as the type of the dict
literal expression itself; the fallback to declared type should happen
at the level of the overall assignment definition.

The reason the latter isn't working yet is because currently we
(wrongly) consider a homogeneous dict type as assignable to a
`TypedDict`, so we don't actually consider the assignment itself as
failed. So the "bug" I observed (and tried to fix) will naturally be
fixed by implementing TypedDict assignability rules.

Rollback https://github.com/astral-sh/ruff/pull/21168 except for the
tests, and modify the tests to include TODOs as needed.

## Test Plan

Updated mdtests.
2025-10-31 12:06:47 -04:00
Luca Chiodini 69b4c29924
Consistently wrap tokens in parser diagnostics in `backticks` instead of 'quotes' (#21163)
The parser currently uses single quotes to wrap tokens. This is
inconsistent with the rest of ruff/ty, which use backticks.

For example, see the inconsistent diagnostics produced in this simple
example: https://play.ty.dev/0a9d6eab-6599-4a1d-8e40-032091f7f50f

Consistently wrapping tokens in backticks produces uniform diagnostics.
Following the style decision of #723, in #2889 some quotes were already
switched into backticks.

This is also in line with Rust's guide on diagnostics
(https://rustc-dev-guide.rust-lang.org/diagnostics.html#diagnostic-structure):

> When code or an identifier must appear in a message or label, it
should be surrounded with backticks
2025-10-31 11:59:11 -04:00
Ibraheem Ahmed bb40c34361
[ty] Use declared attribute types as type context (#21143)
## Summary

For example:
```py
class X:
    x: list[int | str]

def _(x: X):
    x.x = [1]
```

Resolves https://github.com/astral-sh/ty/issues/1375.
2025-10-31 15:48:28 +00:00
Carl Meyer 1d111c8780
[ty] prefer declared type on invalid TypedDict creation (#21168)
## Summary

In general, when we have an invalid assignment (inferred assigned type
is not assignable to declared type), we fall back to inferring the
declared type, since the declared type is a more explicit declaration of
the programmer's intent. This also maintains the invariant that our
inferred type for a name is always assignable to the declared type for
that same name. For example:

```py
x: str = 1
reveal_type(x)  # revealed: str
```

We weren't following this pattern for dictionary literals inferred (via
type context) as a typed dictionary; if the literal was not valid for
the annotated TypedDict type, we would just fall back to the normal
inferred type of the dict literal, effectively ignoring the annotation,
and resulting in inferred type not assignable to declared type.

## Test Plan

Added mdtest assertions.
2025-10-31 11:12:06 -04:00
David Peter 0c2cf75869
[ty] Do not promote literals in contravariant position (#21164)
## Summary

closes https://github.com/astral-sh/ty/issues/1463

## Test Plan

Regression tests
2025-10-31 16:00:30 +01:00
Ibraheem Ahmed 1d6ae8596a
[ty] Prefer exact matches when solving constrained type variables (#21165)
## Summary

The solver is currently order-dependent, and will choose a supertype
over the exact type if it appears earlier in the list of constraints. We
could be smarter and try to choose the most precise subtype, but I
imagine this is something the new constraint solver will fix anyways,
and this fixes the issue showing up on
https://github.com/astral-sh/ruff/pull/21070.
2025-10-31 10:58:09 -04:00
Douglas Creager cf4e82d4b0
[ty] Add and test when constraint sets are satisfied by their typevars (#21129)
This PR adds a new `satisfied_by_all_typevar` method, which implements
one of the final steps of actually using these dang constraint sets.
Constraint sets exist to help us check assignability and subtyping of
types in the presence of typevars. We construct a constraint set
describing the conditions under which assignability holds between the
two types. Then we check whether that constraint set is satisfied for
the valid specializations of the relevant typevars (which is this new
method).

We also add a new `ty_extensions.ConstraintSet` method so that we can
test this method's behavior in mdtests, before hooking it up to the rest
of the specialization inference machinery.
2025-10-31 10:53:37 -04:00
Ibraheem Ahmed 1baf98aab3
[ty] Fix `is_disjoint_from` with `@final` classes (#21167)
## Summary

We currently perform a subtyping check instead of the intended subclass
check (and the subtyping check is confusingly named `is_subclass_of`).
This showed up in https://github.com/astral-sh/ruff/pull/21070.
2025-10-31 14:50:54 +00:00
Carl Meyer 3179b05221
[ty] don't assume in diagnostic messages that a TypedDict key error is about subscript access (#21166)
## Summary

Before this PR, we would emit diagnostics like "Invalid key access" for
a TypedDict literal with invalid key, which doesn't make sense since
there's no "access" in that case. This PR just adjusts the wording to be
more general, and adjusts the documentation of the lint rule too.

I noticed this in the playground and thought it would be a quick fix. As
usual, it turned out to be a bit more subtle than I expected, but for
now I chose to punt on the complexity. We may ultimately want to have
different rules for invalid subscript vs invalid TypedDict literal,
because an invalid key in a TypedDict literal is low severity: it's a
typo detector, but not actually a type error. But then there's another
wrinkle there: if the TypedDict is `closed=True`, then it _is_ a type
error. So would we want to separate the open and closed cases into
separate rules, too? I decided to leave this as a question for future.

If we wanted to use separate rules, or use specific wording for each
case instead of the generalized wording I chose here, that would also
involve a bit of extra work to distinguish the cases, since we use a
generic set of functions for reporting these errors.

## Test Plan

Added and updated mdtests.
2025-10-31 10:49:59 -04:00
Aria Desires 172e8d4ae0
[ty] Support implicit imports of submodules in `__init__.pyi` (#20855)
This is a second take at the implicit imports approach, allowing `from .
import submodule` in an `__init__.pyi` to create the
`mypackage.submodule` attribute everyhere.

This implementation operates inside of the
available_submodule_attributes subsystem instead of as a re-export rule.

The upside of this is we are no longer purely syntactic, and absolute
from imports that happen to target submodules work (an intentional
discussed deviation from pyright which demands a relative from import).
Also we don't re-export functions or classes.

The downside(?) of this is star imports no longer see these attributes
(this may be either good or bad. I believe it's not a huge lift to make
it work with star imports but it's some non-trivial reworking).

I've also intentionally made `import mypackage.submodule` not trigger
this rule although it's trivial to change that.

I've tried to cover as many relevant cases as possible for discussion in
the new test file I've added (there are some random overlaps with
existing tests but trying to add them piecemeal felt confusing and
weird, so I just made a dedicated file for this extension to the rules).

Fixes https://github.com/astral-sh/ty/issues/133

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## Summary

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2025-10-31 14:29:24 +00:00
Mahmoud Saada 735ec0c1f9
[ty] Fix generic inference for non-dataclass inheriting from generic dataclass (#21159)
## Summary

Fixes https://github.com/astral-sh/ty/issues/1427

This PR fixes a regression introduced in alpha.24 where non-dataclass
children of generic dataclasses lost generic type parameter information
during `__init__` synthesis.

The issue occurred because when looking up inherited members in the MRO,
the child class's `inherited_generic_context` was correctly passed down,
but `own_synthesized_member()` (which synthesizes dataclass `__init__`
methods) didn't accept this parameter. It only used
`self.inherited_generic_context(db)`, which returned the parent's
context instead of the child's.

The fix threads the child's generic context through to the synthesis
logic, allowing proper generic type inference for inherited dataclass
constructors.

## Test Plan

- Added regression test for non-dataclass inheriting from generic
dataclass
- Verified the exact repro case from the issue now works
- All 277 mdtest tests passing
- Clippy clean
- Manually verified with Python runtime, mypy, and pyright - all accept
this code pattern

## Verification

Tested against multiple type checkers:
-  Python runtime: Code works correctly
-  mypy: No issues found
-  pyright: 0 errors, 0 warnings
-  ty alpha.23: Worked (before regression)
-  ty alpha.24: Regression
-  ty with this fix: Works correctly

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: David Peter <mail@david-peter.de>
2025-10-31 13:55:17 +01:00
Alex Waygood 13375d0e42
[ty] Use the top materialization of classes for narrowing in class-patterns for `match` statements (#21150) 2025-10-30 20:44:51 +00:00
Douglas Creager c0b04d4b7c
[ty] Update "constraint implication" relation to work on constraints between two typevars (#21068)
It's possible for a constraint to mention two typevars. For instance, in
the body of

```py
def f[S: int, T: S](): ...
```

the baseline constraint set would be `(T ≤ S) ∧ (S ≤ int)`. That is, `S`
must specialize to some subtype of `int`, and `T` must specialize to a
subtype of the type that `S` specializes to.

This PR updates the new "constraint implication" relationship from
#21010 to work on these kinds of constraint sets. For instance, in the
example above, we should be able to see that `T ≤ int` must always hold:

```py
def f[S, T]():
    constraints = ConstraintSet.range(Never, S, int) & ConstraintSet.range(Never, T, S)
    static_assert(constraints.implies_subtype_of(T, int))  # now succeeds!
```

This did not require major changes to the implementation of
`implies_subtype_of`. That method already relies on how our `simplify`
and `domain` methods expand a constraint set to include the transitive
closure of the constraints that it mentions, and to mark certain
combinations of constraints as impossible. Previously, that transitive
closure logic only looked at pairs of constraints that constrain the
same typevar. (For instance, to notice that `(T ≤ bool) ∧ ¬(T ≤ int)` is
impossible.)

Now we also look at pairs of constraints that constraint different
typevars, if one of the constraints is bound by the other — that is,
pairs of the form `T ≤ S` and `S ≤ something`, or `S ≤ T` and `something
≤ S`. In those cases, transitivity lets us add a new derived constraint
that `T ≤ something` or `something ≤ T`, respectively. Having done that,
our existing `implies_subtype_of` logic finds and takes into account
that derived constraint.
2025-10-30 16:11:04 -04:00
Alex Waygood 9bacd19c5a
[ty] Fix lookup of `__new__` on instances (#21147)
## Summary

We weren't correctly modeling it as a `staticmethod` in all cases,
leading us to incorrectly infer that the `cls` argument would be bound
if it was accessed on an instance (rather than the class object).

## Test Plan

Added mdtests that fail on `main`. The primer output also looks good!
2025-10-30 13:42:46 -04:00
David Peter e55bc943e5
[ty] Reachability and narrowing for enum methods (#21130)
## Summary

Adds proper type narrowing and reachability analysis for matching on
non-inferable type variables bound to enums. For example:

```py
from enum import Enum

class Answer(Enum):
    NO = 0
    YES = 1

    def is_yes(self) -> bool:  # no error here!
        match self:
            case Answer.YES:
                return True
            case Answer.NO:
                return False
```

closes https://github.com/astral-sh/ty/issues/1404

## Test Plan

Added regression tests
2025-10-30 15:38:57 +01:00
David Peter 1b0ee4677e
[ty] Use `range` instead of custom `IntIterable` (#21138)
## Summary

We previously didn't understand `range` and wrote these custom
`IntIterable`/`IntIterator` classes for tests. We can now remove them
and make the tests shorter in some places.
2025-10-30 15:21:55 +01:00
David Peter 5139f76d1f
[ty] Infer type of `self` for decorated methods and properties (#21123)
## Summary

Infer a type of unannotated `self` parameters in decorated methods /
properties.

closes https://github.com/astral-sh/ty/issues/1448

## Test Plan

Existing tests, some new tests.
2025-10-29 21:22:38 +00:00
Douglas Creager 17850eee4b
[ty] Reformat constraint set mdtests (#21111)
This PR updates the mdtests that test how our generics solver interacts
with our new constraint set implementation. Because the rendering of a
constraint set can get long, this standardizes on putting the `revealed`
assertion on a separate line. We also add a `static_assert` test for
each constraint set to verify that they are all coerced into simple
`bool`s correctly.

This is a pure reformatting (not even a refactoring!) that changes no
behavior. I've pulled it out of #20093 to reduce the amount of effort
that will be required to review that PR.
2025-10-28 14:59:49 -04:00
Douglas Creager 4d2ee41e24
[ty] Move constraint set mdtest functions into `ConstraintSet` class (#21108)
We have several functions in `ty_extensions` for testing our constraint
set implementation. This PR refactors those functions so that they are
all methods of the `ConstraintSet` class, rather than being standalone
top-level functions. 🎩 to @sharkdp for pointing out that
`KnownBoundMethod` gives us what we need to implement that!
2025-10-28 14:32:41 -04:00
Douglas Creager 29462ea1d4
[ty] Add new "constraint implication" typing relation (#21010)
This PR adds the new **_constraint implication_** relationship between
types, aka `is_subtype_of_given`, which tests whether one type is a
subtype of another _assuming that the constraints in a particular
constraint set hold_.

For concrete types, constraint implication is exactly the same as
subtyping. (A concrete type is any fully static type that is not a
typevar. It can _contain_ a typevar, though — `list[T]` is considered
concrete.)

The interesting case is typevars. The other typing relationships (TODO:
will) all "punt" on the question when considering a typevar, by
translating the desired relationship into a constraint set. At some
point, though, we need to resolve a constraint set; at that point, we
can no longer punt on the question. Unlike with concrete types, the
answer will depend on the constraint set that we are considering.
2025-10-27 22:01:08 -04:00
Alex Waygood db0e921db1
[ty] Fix bug where ty would think all types had an `__mro__` attribute (#20995) 2025-10-27 11:19:12 +00:00
Ibraheem Ahmed 304ac22e74
[ty] Use constructor parameter types as type context (#21054)
## Summary

Resolves https://github.com/astral-sh/ty/issues/1408.
2025-10-24 20:14:18 +00:00
Douglas Creager c3de8847d5
[ty] Consider domain of BDD when checking whether always satisfiable (#21050)
That PR title might be a bit inscrutable.

Consider the two constraints `T ≤ bool` and `T ≤ int`. Since `bool ≤
int`, by transitivity `T ≤ bool` implies `T ≤ int`. (Every type that is
a subtype of `bool` is necessarily also a subtype of `int`.) That means
that `T ≤ bool ∧ T ≰ int` is an impossible combination of constraints,
and is therefore not a valid input to any BDD. We say that that
assignment is not in the _domain_ of the BDD.

The implication `T ≤ bool → T ≤ int` can be rewritten as `T ≰ bool ∨ T ≤
int`. (That's the definition of implication.) If we construct that
constraint set in an mdtest, we should get a constraint set that is
always satisfiable. Previously, that constraint set would correctly
_display_ as `always`, but a `static_assert` on it would fail.

The underlying cause is that our `is_always_satisfied` method would only
test if the BDD was the `AlwaysTrue` terminal node. `T ≰ bool ∨ T ≤ int`
does not simplify that far, because we purposefully keep around those
constraints in the BDD structure so that it's easier to compare against
other BDDs that reference those constraints.

To fix this, we need a more nuanced definition of "always satisfied".
Instead of evaluating to `true` for _every_ input, we only need it to
evaluate to `true` for every _valid_ input — that is, every input in its
domain.
2025-10-24 13:37:56 -04:00
Ibraheem Ahmed f17ddd62ad
[ty] Avoid duplicate diagnostics during multi-inference of standalone expressions (#21056)
## Summary

Resolves https://github.com/astral-sh/ty/issues/1428.
2025-10-24 13:21:39 -04:00
Micha Reiser adbf05802a
[ty] Fix rare panic with highly cyclic `TypeVar` definitions (#21059) 2025-10-24 18:30:54 +02:00
Alex Waygood bf74c824eb
[ty] Delegate truthiness inference of an enum `Literal` type to its enum-instance supertype (#21060) 2025-10-24 14:34:16 +01:00
Alex Waygood e196c2ab37
[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
Shunsuke Shibayama 48f1771877
[ty] fix infinite recursion with generic type aliases (#20969)
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-10-23 14:14:30 +00:00
Alex Waygood dab3d4e917
[ty] Improve `invalid-argument-type` diagnostics where a union type was provided (#21044) 2025-10-23 13:16:21 +00:00
Micha Reiser e92fd51a2c
[ty] Add cycle handling to `lazy_default` (#20967) 2025-10-23 10:05:08 +02:00
David Peter 589e8ac0d9
[ty] Infer type for implicit `self` parameters in method bodies (#20922)
## Summary

Infer a type of `Self` for unannotated `self` parameters in methods of
classes.

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

closes https://github.com/astral-sh/ty/issues/1081

## Conformance tests changes

```diff
+enums_member_values.py:85:9: error[invalid-assignment] Object of type `int` is not assignable to attribute `_value_` of type `str`
```
A true positive ✔️ 

```diff
-generics_self_advanced.py:35:9: error[type-assertion-failure] Argument does not have asserted type `Self@method2`
-generics_self_basic.py:14:9: error[type-assertion-failure] Argument does not have asserted type `Self@set_scale
```

Two false positives going away ✔️ 

```diff
+generics_syntax_infer_variance.py:82:9: error[invalid-assignment] Cannot assign to final attribute `x` on type `Self@__init__`
```

This looks like a true positive to me, even if it's not marked with `#
E` ✔️

```diff
+protocols_explicit.py:56:9: error[invalid-assignment] Object of type `tuple[int, int, str]` is not assignable to attribute `rgb` of type `tuple[int, int, int]`
```

True positive ✔️ 

```
+protocols_explicit.py:85:9: error[invalid-attribute-access] Cannot assign to ClassVar `cm1` from an instance of type `Self@__init__`
```

This looks like a true positive to me, even if it's not marked with `#
E`. But this is consistent with our understanding of `ClassVar`, I
think. ✔️

```py
+qualifiers_final_annotation.py:52:9: error[invalid-assignment] Cannot assign to final attribute `ID4` on type `Self@__init__`
+qualifiers_final_annotation.py:65:9: error[invalid-assignment] Cannot assign to final attribute `ID7` on type `Self@method1`
```

New true positives ✔️ 

```py
+qualifiers_final_annotation.py:52:9: error[invalid-assignment] Cannot assign to final attribute `ID4` on type `Self@__init__`
+qualifiers_final_annotation.py:57:13: error[invalid-assignment] Cannot assign to final attribute `ID6` on type `Self@__init__`
+qualifiers_final_annotation.py:59:13: error[invalid-assignment] Cannot assign to final attribute `ID6` on type `Self@__init__`
```

This is a new false positive, but that's a pre-existing issue on main
(if you annotate with `Self`):
https://play.ty.dev/3ee1c56d-7e13-43bb-811a-7a81e236e6ab  => reported
as https://github.com/astral-sh/ty/issues/1409

## Ecosystem

* There are 5931 new `unresolved-attribute` and 3292 new
`possibly-missing-attribute` attribute errors, way too many to look at
all of them. I randomly sampled 15 of these errors and found:
* 13 instances where there was simply no such attribute that we could
plausibly see. Sometimes [I didn't find it
anywhere](8644d886c6/openlibrary/plugins/openlibrary/tests/test_listapi.py (L33)).
Sometimes it was set externally on the object. Sometimes there was some
[`setattr` dynamicness going
on](a49f6b927d/setuptools/wheel.py (L88-L94)).
I would consider all of them to be true positives.
* 1 instance where [attribute was set on `obj` in
`__new__`](9e87b44fd4/sympy/tensor/array/array_comprehension.py (L45C1-L45C36)),
which we don't support yet
  * 1 instance [where the attribute was defined via `__slots__`

](e250ec0fc8/lib/spack/spack/vendor/pyrsistent/_pdeque.py (L48C5-L48C14))
* I see 44 instances [of the false positive
above](https://github.com/astral-sh/ty/issues/1409) with `Final`
instance attributes being set in `__init__`. I don't think this should
block this PR.

## Test Plan

New Markdown tests.

---------

Co-authored-by: Shaygan Hooshyari <sh.hooshyari@gmail.com>
2025-10-23 09:34:39 +02:00
Douglas Creager 766ed5b5f3
[ty] Some more simplifications when rendering constraint sets (#21009)
This PR adds another useful simplification when rendering constraint
sets: `T = int` instead of `T = int ∧ T ≠ str`. (The "smaller"
constraint `T = int` implies the "larger" constraint `T ≠ str`.
Constraint set clauses are intersections, and if one constraint in a
clause implies another, we can throw away the "larger" constraint.)

While we're here, we also normalize the bounds of a constraint, so that
we equate e.g. `T ≤ int | str` with `T ≤ str | int`, and change the
ordering of BDD variables so that all constraints with the same typevar
are ordered adjacent to each other.

Lastly, we also add a new `display_graph` helper method that prints out
the full graph structure of a BDD.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-10-22 13:38:44 -04:00
David Peter 81c1d36088
[ty] Make `attributes.md` mdtests faster (#21030)
## Summary

That example was too extreme for debug mode.
2025-10-22 16:40:58 +02:00
David Peter 58a68f1bbd
[ty] Fall back to `Divergent` for deeply nested specializations (#20988)
## Summary

Fall back to `C[Divergent]` if we are trying to specialize `C[T]` with a
type that itself already contains deeply nested specialized generic
classes. This is a way to prevent infinite recursion for cases like
`self.x = [self.x]` where type inference for the implicit instance
attribute would not converge.

closes https://github.com/astral-sh/ty/issues/1383
closes https://github.com/astral-sh/ty/issues/837

## Test Plan

Regression tests.
2025-10-22 14:29:10 +02:00
David Peter 2dbca6370b
[ty] Avoid ever-growing default types (#20991)
## Summary

We currently panic in the seemingly rare case where the type of a
default value of a parameter depends on the callable itself:
```py
class C:
    def f(self: C):
        self.x = lambda a=self.x: a
```

Types of default values are only used for display reasons, and it's
unclear if we even want to track them (or if we should rather track the
actual value). So it didn't seem to me that we should spend a lot of
effort (and runtime) trying to achieve a theoretically correct type here
(which would be infinite).

Instead, we simply replace *nested* default types with `Unknown`, i.e.
only if the type of the default value is a callable itself.

closes https://github.com/astral-sh/ty/issues/1402

## Test Plan

Regression tests
2025-10-21 19:13:36 +02:00
David Peter e1cada1ec3
[ty] Disable panicking mdtest (#21016)
## Summary

Only run the "pull types" test after performing the "actual" mdtest. We
observed that the order matters. There is currently one mdtest which
panics when checked in the CLI or the playground. With this change, it
also panics in the mdtest suite.

reopens https://github.com/astral-sh/ty/issues/837?
2025-10-21 14:40:23 +02:00
Alex Waygood 1f8297cfe6
[ty] Improve error messages for unresolved attribute diagnostics (#20963)
## Summary

- Type checkers (and type-checker authors) think in terms of types, but
I think most Python users think in terms of values. Rather than saying
that a _type_ `X` "has no attribute `foo`" (which I think sounds strange
to many users), say that "an object of type `X` has no attribute `foo`"
- Special-case certain types so that the diagnostic messages read more
like normal English: rather than saying "Type `<class 'Foo'>` has no
attribute `bar`" or "Object of type `<class 'Foo'>` has no attribute
`bar`", just say "Class `Foo` has no attribute `bar`"

## Test Plan

Mdtests and snapshots updated
2025-10-19 10:58:25 +01:00
David Peter 3c229ae58a
[ty] `dataclass_transform`: Support for fields with an `alias` (#20961)
## Summary

closes https://github.com/astral-sh/ty/issues/1385

## Conformance tests

Two false positives removed, as expected.

## Test Plan

New Markdown tests
2025-10-18 18:20:39 +00:00
Alex Waygood 68c1fa86c8
[ty] Fix panic when attempting to validate the members of a protocol that inherits from a protocol in another module (#20956) 2025-10-18 15:01:46 +01:00
Alex Waygood 16efe53a72
[ty] Fix panic on recursive class definitions in a stub that use constrained type variables (#20955) 2025-10-18 13:02:55 +00:00
Micha Reiser 7532155c9b
[ty] Add suggestion to unknown rule diagnostics, rename `unknown-rule` lint to `ignore-comment-unknown-rule` (#20948) 2025-10-18 12:44:21 +02:00
Bhuminjay Soni 7198e53182
[syntax-errors] Alternative `match` patterns bind different names (#20682)
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## Summary

<!-- What's the purpose of the change? What does it do, and why? -->
This PR implements semantic syntax error where alternative patterns bind
different names

## Test Plan

<!-- How was it tested? -->
I have written inline tests as directed in #17412

---------

Signed-off-by: 11happy <soni5happy@gmail.com>
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
2025-10-17 21:35:48 +00:00
Shunsuke Shibayama e4384fc212
[ty] impl `VarianceInferable` for `KnownInstanceType` (#20924)
## Summary

Derived from #20900

Implement `VarianceInferable` for `KnownInstanceType` (especially for
`KnownInstanceType::TypeAliasType`).

The variance of a type alias matches its value type. In normal usage,
type aliases are expanded to value types, so the variance of a type
alias can be obtained without implementing this. However, for example,
if we want to display the variance when hovering over a type alias, we
need to be able to obtain the variance of the type alias itself (cf.
#20900).

## Test Plan

I couldn't come up with a way to test this in mdtest, so I'm testing it
in a test submodule at the end of `types.rs`.
I also added a test to `mdtest/generics/pep695/variance.md`, but it
passes without the changes in this PR.
2025-10-17 21:12:19 +02:00
Alex Waygood c7e2bfd759
[ty] `continue` and `break` statements outside loops are syntax errors (#20944)
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
2025-10-17 17:13:40 +00:00
David Peter cfbd42c22a
[ty] Support `dataclass_transform` for base class models (#20783)
## Summary

Support `dataclass_transform` when used on a (base) class.

## Typing conformance

* The changes in `dataclasses_transform_class.py` look good, just a few
mistakes due to missing `alias` support.
* I didn't look closely at the changes in
`dataclasses_transform_converter.py` since we don't support `converter`
yet.

## Ecosystem impact

The impact looks huge, but it's concentrated on a single project (ibis).
Their setup looks more or less like this:

* the real `Annotatable`:
d7083c2c96/ibis/common/grounds.py (L100-L101)
* the real `DataType`:
d7083c2c96/ibis/expr/datatypes/core.py (L161-L179)
* the real `Array`:
d7083c2c96/ibis/expr/datatypes/core.py (L1003-L1006)


```py
from typing import dataclass_transform

@dataclass_transform()
class Annotatable:
    pass

class DataType(Annotatable):
    nullable: bool = True

class Array[T](DataType):
    value_type: T
```

They expect something like `Array([1, 2])` to work, but ty, pyright,
mypy, and pyrefly would all expect there to be a first argument for the
`nullable` field on `DataType`. I don't really understand on what
grounds they expect the `nullable` field to be excluded from the
signature, but this seems to be the main reason for the new diagnostics
here. Not sure if related, but it looks like their typing setup is not
really complete
(https://github.com/ibis-project/ibis/issues/6844#issuecomment-1868274770,
this thread also mentions `dataclass_transform`).

## Test Plan

Update pre-existing tests.
2025-10-17 14:04:31 +02:00
Mark Z. Ding fc3b341529
[ty] Truncate Literal type display in some situations (#20928) 2025-10-17 11:50:58 +00:00
Aria Desires 64edfb6ef6
[ty] add legacy namespace package support (#20897)
Detect legacy namespace packages and treat them like namespace packages
when looking them up as the *parent* of the module we're interested in.
In all other cases treat them like a regular package.

(This PR is coauthored by @MichaReiser in a shared coding session)

Fixes https://github.com/astral-sh/ty/issues/838

---------

Co-authored-by: Micha Reiser <micha@reiser.io>
2025-10-17 03:16:37 +00:00
Ibraheem Ahmed 96b156303b
[ty] Prefer declared type for invariant collection literals (#20927)
## Summary

Prefer the declared type for collection literals, e.g.,
```py
x: list[Any] = [1, "2", (3,)]
reveal_type(x)  # list[Any]
```

This solves a large part of https://github.com/astral-sh/ty/issues/136
for invariant generics, where respecting the declared type is a lot more
important. It also means that annotated dict literals with `dict[_,
Any]` is a way out of https://github.com/astral-sh/ty/issues/1248.
2025-10-16 16:11:28 -04:00
Ibraheem Ahmed 25023cc0ea
[ty] Use declared variable types as bidirectional type context (#20796)
## Summary

Use the declared type of variables as type context for the RHS of assignment expressions, e.g.,
```py
x: list[int | str]
x = [1]
reveal_type(x)  # revealed: list[int | str]
```
2025-10-16 15:40:39 -04:00
Ibraheem Ahmed 1ade4f2081
[ty] Avoid unnecessarily widening generic specializations (#20875)
## Summary

Ignore the type context when specializing a generic call if it leads to
an unnecessarily wide return type. For example, [the example mentioned
here](https://github.com/astral-sh/ruff/pull/20796#issuecomment-3403319536)
works as expected after this change:
```py
def id[T](x: T) -> T:
    return x

def _(i: int):
    x: int | None = id(i)
    y: int | None = i
    reveal_type(x)  # revealed: int
    reveal_type(y)  # revealed: int
```

I also added extended our usage of `filter_disjoint_elements` to tuple
and typed-dict inference, which resolves
https://github.com/astral-sh/ty/issues/1266.
2025-10-16 19:17:37 +00:00
David Peter 8dad58de37
[ty] Support dataclass-transform `field_specifiers` (#20888)
## Summary

Add support for the `field_specifiers` parameter on
`dataclass_transform` decorator calls.

closes https://github.com/astral-sh/ty/issues/1068

## Conformance test results

All true positives ✔️ 

## Ecosystem analysis

* `trio`: this is the kind of change that I would expect from this PR.
The code makes use of a dataclass `Outcome` with a `_unwrapped: bool =
attr.ib(default=False, eq=False, init=False)` field that is excluded
from the `__init__` signature, so we now see a bunch of
constructor-call-related errors going away.
* `home-assistant/core`: They have a `domain: str = attr.ib(init=False,
repr=False)` field and then use
  ```py
    @domain.default
    def _domain_default(self) -> str:
        # …
  ```
This accesses the `default` attribute on `dataclasses.Field[…]` with a
type of `default: _T | Literal[_MISSING_TYPE.MISSING]`, so we get those
"Object of type `_MISSING_TYPE` is not callable" errors. I don't really
understand how that is supposed to work. Even if `_MISSING_TYPE` would
be absent from that union, what does this try to call? pyright also
issues an error and it doesn't seem to work at runtime? So this looks
like a true positive?
* `attrs`: Similar here. There are some new diagnostics on code that
tries to access `.validator` on a field. This *does* work at runtime,
but I'm not sure how that is supposed to type-check (without a [custom
plugin](2c6c395935/mypy/plugins/attrs.py (L575-L602))).
pyright errors on this as well.
* A handful of new false positives because we don't support `alias` yet

## Test Plan

Updated tests.
2025-10-16 20:49:11 +02:00
Brent Westbrook e64d772788
Standardize syntax error construction (#20903)
Summary
--

This PR unifies the two different ways Ruff and ty construct syntax
errors. Ruff has been storing the primary message in the diagnostic
itself, while ty attached the message to the primary annotation:

```
> ruff check try.py
invalid-syntax: name capture `x` makes remaining patterns unreachable
 --> try.py:2:10
  |
1 | match 42:
2 |     case x: ...
  |          ^
3 |     case y: ...
  |

Found 1 error.
> uvx ty check try.py
WARN ty is pre-release software and not ready for production use. Expect to encounter bugs, missing features, and fatal errors.
Checking ------------------------------------------------------------ 1/1 files                                                                                                 
error[invalid-syntax]
 --> try.py:2:10
  |
1 | match 42:
2 |     case x: ...
  |          ^ name capture `x` makes remaining patterns unreachable
3 |     case y: ...
  |

Found 1 diagnostic
```

I think there are benefits to both approaches, and I do like ty's
version, but I feel like we should pick one (and it might help with
#20901 eventually). I slightly prefer Ruff's version, so I went with
that. Hopefully this isn't too controversial, but I'm happy to close
this if it is.

Note that this shouldn't change any other diagnostic formats in ty
because
[`Diagnostic::primary_message`](98d27c4128/crates/ruff_db/src/diagnostic/mod.rs (L177))
was already falling back to the primary annotation message if the
diagnostic message was empty. As a result, I think this change will
partially resolve the FIXME therein.

Test Plan
--

Existing tests with updated snapshots
2025-10-16 11:56:32 -04:00
Aria Desires 7155a62e5c
[ty] Add version hint for failed stdlib attribute accesses (#20909)
This is the ultra-minimal implementation of

* https://github.com/astral-sh/ty/issues/296

that was previously discussed as a good starting point. In particular we
don't actually bother trying to figure out the exact python versions,
but we still mention "hey btw for No Reason At All... you're on python
3.10" when you try to access something that has a definition rooted in
the stdlib that we believe exists sometimes.
2025-10-16 14:07:33 +00:00
Aria Desires 6a1e91ce97
[ty] Check typeshed VERSIONS for parent modules when reporting failed stdlib imports (#20908)
This is a drive-by improvement that I stumbled backwards into while
looking into

* https://github.com/astral-sh/ty/issues/296

I was writing some simple tests for "thing not in old version of stdlib"
diagnostics and checked what was added in 3.14, and saw
`compression.zstd` and to my surprise discovered that `import
compression.zstd` and `from compression import zstd` had completely
different quality diagnostics.

This is because `compression` and `compression.zstd` were *both*
introduced in 3.14, and so per VERSIONS policy only an entry for
`compression` was added, and so we don't actually have any definite info
on `compression.zstd` and give up on producing a diagnostic. However the
`from compression import zstd` form fails on looking up `compression`
and we *do* have an exact match for that, so it gets a better
diagnostic!

(aside: I have now learned about the VERSIONS format and I *really* wish
they would just enumerate all the submodules but, oh well!)

The fix is, when handling an import failure, if we fail to find an exact
match *we requery with the parent module*. In cases like
`compression.zstd` this lets us at least identify that, hey, not even
`compression` exists, and luckily that fixes the whole issue. In cases
where the parent module and submodule were introduced at different times
then we may discover that the parent module is in-range and that's fine,
we don't produce the richer stdlib diagnostic.
2025-10-16 13:25:08 +00:00
Carl Meyer d23826ce46
[ty] cache Type::is_redundant_with (#20477)
Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
2025-10-16 13:46:56 +02:00
Micha Reiser 5fb142374d
Fix run-away for mutually referential instance attributes (#20645) 2025-10-16 13:24:41 +02:00
David Peter c8133104e8
[ty] Use field-specifier return type as the default type for the field (#20915)
## Summary

`dataclasses.field` and field-specifier functions of commonly used
libraries like `pydantic`, `attrs`, and `SQLAlchemy` all return the
default type for the field (or `Any`) instead of an actual `Field`
instance, even if this is not what happens at runtime. Let's make use of
this fact and assume that *all* field specifiers return the type of the
default value of the field.

For standard dataclasses, this leads to more or less the same outcome
(see test diff for details), but this change is important for 3rd party
dataclass-transformers.

## Test Plan

Tested the consequences of this change on the field-specifiers branch as
well.
2025-10-16 13:13:45 +02:00
David Peter 0cc663efcd
[ty] Do not assume that `field`s have a default value (#20914)
## Summary

fixes https://github.com/astral-sh/ty/issues/1366

## Test Plan

Added regression test
2025-10-16 12:49:24 +02:00
Eric Mark Martin c9dfb51f49
[ty] Fix match pattern value narrowing to use equality semantics (#20882)
## Summary

Resolves https://github.com/astral-sh/ty/issues/1349.

Fix match statement value patterns to use equality comparison semantics
instead of incorrectly narrowing to literal types directly. Value
patterns use equality for matching, and equality can be overridden, so
we can't always narrow to the matched literal.

## Test Plan

Updated match.md with corrected expected types and an additional example
with explanation

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-10-16 07:50:32 +00:00
Alex Waygood fd568f0221
[ty] Heterogeneous unpacking support for unions (#20377) 2025-10-15 19:30:03 +01:00
github-actions[bot] cafb96aa7a
[ty] Sync vendored typeshed stubs (#20876)
Close and reopen this PR to trigger CI

---------

Co-authored-by: typeshedbot <>
Co-authored-by: David Peter <mail@david-peter.de>
2025-10-15 11:13:32 +02:00
Alex Waygood 43eddc566f
[ty] Improve and extend tests for instance attributes redeclared in subclasses (#20866)
Part of https://github.com/astral-sh/ty/issues/1345
2025-10-14 19:31:34 +01:00
Alex Waygood 9090aead0f
[ty] Fix further issues in `super()` inference logic (#20843) 2025-10-14 12:48:47 +00:00
David Peter 6341bb7403
[ty] Treat `Callable` dunder members as bound method descriptors (#20860)
## Summary

Dunder methods (at least the ones defined in the standard library)
always take an instance of the class as the first parameter. So it seems
reasonable to generally treat them as bound method descriptors if they
are defined via a `Callable` type.

This removes just a few false positives from the ecosystem, but solves
three user-reported issues:

closes https://github.com/astral-sh/ty/issues/908
closes https://github.com/astral-sh/ty/issues/1143
closes https://github.com/astral-sh/ty/issues/1209

In addition to the change here, I also considered [making `ClassVar`s
bound method descriptors](https://github.com/astral-sh/ruff/pull/20861).
However, there was zero ecosystem impact. So I think we can also close
https://github.com/astral-sh/ty/issues/491 with this PR.

closes https://github.com/astral-sh/ty/issues/491

## Test Plan

Added regression test
2025-10-14 14:27:52 +02:00
David Peter ac2c530377
[ty] Handle decorators which return unions of `Callable`s (#20858)
## Summary

If a function is decorated with a decorator that returns a union of
`Callable`s, also treat it as a union of function-like `Callable`s.

Labeling as `internal`, since the previous change has not been released
yet.

## Test Plan

New regression test.
2025-10-14 09:47:50 +00:00
Douglas Creager aba0bd568e
[ty] Diagnostic for generic classes that reference typevars in enclosing scope (#20822)
Generic classes are not allowed to bind or reference a typevar from an
enclosing scope:

```py
def f[T](x: T, y: T) -> None:
    class Ok[S]: ...
    # error: [invalid-generic-class]
    class Bad1[T]: ...
    # error: [invalid-generic-class]
    class Bad2(Iterable[T]): ...

class C[T]:
    class Ok1[S]: ...
    # error: [invalid-generic-class]
    class Bad1[T]: ...
    # error: [invalid-generic-class]
    class Bad2(Iterable[T]): ...
```

It does not matter if the class uses PEP 695 or legacy syntax. It does
not matter if the enclosing scope is a generic class or function. The
generic class cannot even _reference_ an enclosing typevar in its base
class list.

This PR adds diagnostics for these cases.

In addition, the PR adds better fallback behavior for generic classes
that violate this rule: any enclosing typevars are not included in the
class's generic context. (That ensures that we don't inadvertently try
to infer specializations for those typevars in places where we
shouldn't.) The `dulwich` ecosystem project has [examples of
this](d912eaaffd/dulwich/config.py (L251))
that were causing new false positives on #20677.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-10-13 19:30:49 -04:00
David Peter 4b8e278a88
[ty] Treat `Callable`s as bound-method descriptors in special cases (#20802)
## Summary

Treat `Callable`s as bound-method descriptors if `Callable` is the
return type of a decorator that is applied to a function definition. See
the [rendered version of the new test
file](https://github.com/astral-sh/ruff/blob/david/callables-as-descriptors/crates/ty_python_semantic/resources/mdtest/call/callables_as_descriptors.md)
for the full description of this new heuristic.

I could imagine that we want to treat `Callable`s as bound-method
descriptors in other cases as well, but this seems like a step in the
right direction. I am planning to add other "use cases" from
https://github.com/astral-sh/ty/issues/491 to this test suite.

partially addresses https://github.com/astral-sh/ty/issues/491
closes https://github.com/astral-sh/ty/issues/1333

## Ecosystem impact

All positive

* 2961 removed `unsupported-operator` diagnostics on `sympy`, which was
one of the main motivations for implementing this change
* 37 removed `missing-argument` diagnostics, and no added call-error
diagnostics, which is an indicator that this heuristic shouldn't cause
many false positives
* A few removed `possibly-missing-attribute` diagnostics when accessing
attributes like `__name__` on decorated functions. The two added
`unused-ignore-comment` diagnostics are also cases of this.
* One new `invalid-assignment` diagnostic on `dd-trace-py`, which looks
suspicious, but only because our `invalid-assignment` diagnostics are
not great. This is actually a "Implicit shadowing of function"
diagnostic that hides behind the `invalid-assignment` diagnostic,
because a module-global function is being patched through a
`module.func` attribute assignment.

## Test Plan

New Markdown tests.
2025-10-13 21:17:47 +02:00
David Peter d912f13661
[ty] Do not bind self to non-positional parameters (#20850)
## Summary

closes https://github.com/astral-sh/ty/issues/1333

## Test Plan

Regression test
2025-10-13 20:44:27 +02:00
David Peter 195e8f0684
[ty] Treat functions, methods, and dynamic types as function-like `Callable`s (#20842)
## Summary

Treat functions, methods, and dynamic types as function-like `Callable`s

closes https://github.com/astral-sh/ty/issues/1342
closes https://github.com/astral-sh/ty/issues/1344

## Ecosystem analysis

All removed diagnostics look like cases of
https://github.com/astral-sh/ty/issues/1344

## Test Plan

Added regression test
2025-10-13 15:21:55 +02:00
Alex Waygood d83d7a0dcd
[ty] Fix false-positive diagnostics on `super()` calls (#20814) 2025-10-13 10:57:46 +00:00
David Peter 9b9c9ae092
[ty] Prefer declared base class attribute over inferred attribute on subclass (#20764)
## Summary

When accessing an (instance) attribute on a given class, we were
previously traversing its MRO, and building a union of types (if the
attribute was available on multiple classes in the MRO) until we found a
*definitely bound* symbol. The idea was that possibly unbound symbols in
a subclass might only partially shadow the underlying base class
attribute.

This behavior was problematic for two reasons:
* if the attribute was definitely bound on a class (e.g. `self.x =
None`), we would have stopped iterating, even if there might be a `x:
str | None` declaration in a base class (the bug reported in
https://github.com/astral-sh/ty/issues/1067).
* if the attribute originated from an implicit instance attribute
assignment (e.g. `self.x = 1` in method `Sub.foo`), we might stop
looking and miss another implicit instance attribute assignment in a
base class method (e.g. `self.x = 2` in method `Base.bar`).

With this fix, we still iterate the MRO of the class, but we only stop
iterating if we find a *definitely declared* symbol. In this case, we
only return the declared attribute type. Otherwise, we keep building a
union of inferred attribute types.

The implementation here seemed to be the easiest fix for
https://github.com/astral-sh/ty/issues/1067 that also kept the ecosystem
impact low (the changes that I see all look correct). However, as the
Markdown tests show, there are other things to fix in this area. For
example, we should do a similar thing for *class attributes*. This is
more involved, though (affects many different areas and probably
involves a change to our descriptor protocol implementation), so I'd
like to postpone this to a follow-up.

closes https://github.com/astral-sh/ty/issues/1067

## Test Plan

Updated Markdown tests, including a regression test for
https://github.com/astral-sh/ty/issues/1067.
2025-10-13 09:28:57 +02:00
Alex Waygood 7064c38e53
[ty] Filter out `revealed-type` and `undefined-reveal` diagnostics from mdtest snapshots (#20820) 2025-10-12 18:39:32 +00:00
Shunsuke Shibayama dc64c08633
[ty] bidirectional type inference using function return type annotations (#20528)
## Summary

Implements bidirectional type inference using function return type
annotations.

This PR was originally proposed to solve astral-sh/ty#1167, but this
does not fully resolve it on its own.
Additionally, I believe we need to allow dataclasses to generate their
own `__new__` methods, [use constructor return types ​​for
inference](5844c0103d/crates/ty_python_semantic/src/types.rs (L5326-L5328)),
and a mechanism to discard type narrowing like `& ~AlwaysFalsy` if
necessary (at a more general level than this PR).

## Test Plan

`mdtest/bidirectional.md` is added.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Ibraheem Ahmed <ibraheem@ibraheem.ca>
2025-10-11 00:38:35 +00:00
Shunsuke Shibayama 11a9e7ee44
[ty] use type context more aggressively to infer values ​​when constructing a `TypedDict` (#20806)
## Summary

Based on @ibraheemdev's comment on #20792:

> I think we can also update our bidirectional inference code, [which
makes the same
assumption](https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/src/types/infer/builder.rs?rgh-link-date=2025-10-09T21%3A30%3A31Z#L5860).

This PR also adds more test cases for how `TypedDict` annotations affect
generic call inference.

## Test Plan

New tests in `typed_dict.md`
2025-10-10 16:51:16 -07:00
David Peter ae83a1fd2d
[ty] Additional tests for `dataclass_transform` (class-level overwrites, `field_specifiers`) (#20788)
## Summary

Adds a set of basic new tests corresponding to open points in
https://github.com/astral-sh/ty/issues/1327, to document the state of
support for `dataclass_transform`.
2025-10-10 11:22:06 +00:00
Alex Waygood 44807c4a05
[ty] Better implementation of assignability for intersections with negated gradual elements (#20773) 2025-10-10 11:10:17 +00:00
David Peter 69f9182033
[ty] Annotations are deferred by default for 3.14+ (#20799)
## Summary

Type annotations are deferred by default starting with Python 3.14. No
`from __future__ import annotations` import is necessary.

## Test Plan

New Markdown test
2025-10-10 12:05:03 +02:00
David Peter 949a4f1c42
[ty] Simplify and fix `CallableTypeOf[..]` implementation (#20797)
## Summary

Simplify and fix the implementation of
`ty_extensions.CallableTypeOf[..]`.

closes https://github.com/astral-sh/ty/issues/1331

## Test Plan

Added regression test.
2025-10-10 12:04:37 +02:00
David Peter a82833a998
[ty] Update mypy_primer and project lists (#20798)
## Summary

Pulls in two updates to `mypy_primer` projects:

* https://github.com/hauntsaninja/mypy_primer/pull/201 (add
`django-test-migrations`)
* https://github.com/hauntsaninja/mypy_primer/pull/122 (remove
`SinbadCogs`)

## Test Plan

CI on this PR
2025-10-10 11:08:39 +02:00
Carl Meyer 8248193ed9
[ty] defer inference of legacy TypeVar bound/constraints/defaults (#20598)
## Summary

This allows us to handle self-referential bounds/constraints/defaults
without panicking.

Handles more cases from https://github.com/astral-sh/ty/issues/256

This also changes the way we infer the types of legacy TypeVars. Rather
than understanding a constructor call to `typing[_extension].TypeVar`
inside of any (arbitrarily nested) expression, and having to use a
special `assigned_to` field of the semantic index to try to best-effort
figure out what name the typevar was assigned to, we instead understand
the creation of a legacy `TypeVar` only in the supported syntactic
position (RHS of a simple un-annotated assignment with one target). In
any other position, we just infer it as creating an opaque instance of
`typing.TypeVar`. (This behavior matches all other type checkers.)

So we now special-case TypeVar creation in `TypeInferenceBuilder`, as a
special case of an assignment definition, rather than deeper inside call
binding. This does mean we re-implement slightly more of
argument-parsing, but in practice this is minimal and easy to handle
correctly.

This is easier to implement if we also make the RHS of a simple (no
unpacking) one-target assignment statement no longer a standalone
expression. Which is fine to do, because simple one-target assignments
don't need to infer the RHS more than once. This is a bonus performance
(0-3% across various projects) and significant memory-usage win, since
most assignment statements are simple one-target assignment statements,
meaning we now create many fewer standalone-expression salsa
ingredients.

This change does mean that inference of manually-constructed
`TypeAliasType` instances can no longer find its Definition in
`assigned_to`, which regresses go-to-definition for these aliases. In a
future PR, `TypeAliasType` will receive the same treatment that
`TypeVar` did in this PR (moving its special-case inference into
`TypeInferenceBuilder` and supporting it only in the correct syntactic
position, and lazily inferring its value type to support recursion),
which will also fix the go-to-definition regression. (I decided a
temporary edge-case regression is better in this case than doubling the
size of this PR.)

This PR also tightens up and fixes various aspects of the validation of
`TypeVar` creation, as seen in the tests.

We still (for now) treat all typevars as instances of `typing.TypeVar`,
even if they were created using `typing_extensions.TypeVar`. This means
we'll wrongly error on e.g. `T.__default__` on Python 3.11, even if `T`
is a `typing_extensions.TypeVar` instance at runtime. We share this
wrong behavior with both mypy and pyrefly. It will be easier to fix
after we pull in https://github.com/python/typeshed/pull/14840.

There are some issues that showed up here with typevar identity and
`MarkTypeVarsInferable`; the fix here (using the new `original` field
and `is_identical_to` methods on `BoundTypeVarInstance` and
`TypeVarInstance`) is a bit kludgy, but it can go away when we eliminate
`MarkTypeVarsInferable`.

## Test Plan

Added and updated mdtests.

### Conformance suite impact

The impact here is all positive:

* We now correctly error on a legacy TypeVar with exactly one constraint
type given.
* We now correctly error on a legacy TypeVar with both an upper bound
and constraints specified.

### Ecosystem impact

Basically none; in the setuptools case we just issue slightly different
errors on an invalid TypeVar definition, due to the modified validation
code.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-10-09 21:08:37 +00:00
Ibraheem Ahmed b086ffe921
[ty] Type-context aware literal promotion (#20776)
## Summary

Avoid literal promotion when a literal type annotation is provided, e.g.,
```py
x: list[Literal[1]] = [1]
```

Resolves https://github.com/astral-sh/ty/issues/1198. This does not fix
issue https://github.com/astral-sh/ty/issues/1284, but it does make it
more relevant because after this change, it is possible to directly
instantiate a generic type with a literal specialization.
2025-10-09 16:53:53 -04:00
Shunsuke Shibayama db91ac7dce
[ty] allow any string `Literal` type expression as a key when constructing a `TypedDict` (#20792) 2025-10-09 18:24:11 +00:00
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
Alex Waygood 888a22e849
[ty] Reduce false positives for `ParamSpec`s and `TypeVarTuple`s (#20239) 2025-09-04 23:34:37 +01:00
Jelle Zijlstra 08c1d3660c
[ty] Narrow specialized generics using isinstance() (#20256)
Closes astral-sh/ty#456. Part of astral-sh/ty#994.

After all the foundational work, this is only a small change, but let's
see if it exposes any unresolved issues.
2025-09-04 15:28:33 -07:00
Jelle Zijlstra de63f408b9
[ty] Attribute access on top/bottom materializations (#20221)
## Summary

Part of astral-sh/ty#994. The goal of this PR was to add correct
behavior for attribute access on the top and bottom materializations.
This is necessary for the end goal of using the top materialization for
narrowing generics (`isinstance(x, list)`): we want methods like
`x.append` to work correctly in that case.

It turned out to be convenient to represent materialization as a
TypeMapping, so it can be stashed in the `type_mappings` list of a
function object. This also allowed me to remove most concrete
`materialize` methods, since they usually just delegate to the subparts
of the type, the same as other type mappings. That is why the net effect
of this PR is to remove a few hundred lines.

## Test Plan

I added a few more tests. Much of this PR is refactoring and covered by
existing tests.

## Followups

Assigning to attributes of top materializations is not yet covered. This
seems less important so I'd like to defer it.

I noticed that the `materialize` implementation of `Parameters` was
wrong; it did the same for the top and bottom materializations. This PR
makes the bottom materialization slightly more reasonable, but
implementing this correctly will require extending the struct.
2025-09-04 12:01:44 -07:00
David Peter 1aaa0847ab
[ty] More tests for TypedDict (#20205)
## Summary

A small set of additional tests for `TypedDict` that I wrote while going
through the spec. Note that this certainly doesn't make the test suite
exhaustive (see remaining open points in the updated list here:
https://github.com/astral-sh/ty/issues/154).
2025-09-04 15:55:42 +00:00
Samuel Rigaud 1e34f3f20a
[ty] Fix small test typo (#20220)
Small typo in the comment of a test

Co-authored-by: Samuel Rigaud <rigaud@gmail.com>
2025-09-03 15:24:17 -07:00
Douglas Creager 77b2cee223
[ty] Add functions for revealing assignability/subtyping constraints (#20217)
This PR adds two new `ty_extensions` functions,
`reveal_when_assignable_to` and `reveal_when_subtype_of`. These are
closely related to the existing `is_assignable_to` and `is_subtype_of`,
but instead of returning when the property (always) holds, it produces a
diagnostic that describes _when_ the property holds. (This will let us
construct mdtests that print out constraints that are not always true or
always false — though we don't currently have any instances of those.)

I did not replace _every_ occurrence of the `is_property` variants in
the mdtest suite, instead focusing on the generics-related tests where
it will be important to see the full detail of the constraint sets.

As part of this, I also updated the mdtest harness to accept the shorter
`# revealed:` assertion format for more than just `reveal_type`, and
updated the existing uses of `reveal_protocol_interface` to take
advantage of this.
2025-09-03 16:44:35 -04:00
Renkai Ge cda376afe0
[ty]eliminate definitely-impossible types from union in equality narrowing (#20164)
solves https://github.com/astral-sh/ty/issues/939

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-09-03 08:34:22 -07:00
Bhuminjay Soni 4c3e1930f6
[syntax-errors] Detect `yield from` inside async function (#20051)
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## Summary

This PR implements
https://docs.astral.sh/ruff/rules/yield-from-in-async-function/ as a
syntax semantic error

## Test Plan

<!-- How was it tested? -->
I have written a simple inline test as directed in
[https://github.com/astral-sh/ruff/issues/17412](https://github.com/astral-sh/ruff/issues/17412)

---------

Signed-off-by: 11happy <soni5happy@gmail.com>
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
2025-09-03 10:13:05 -04:00
David Peter bbfcf6e111
[ty] `__class_getitem__` is a classmethod (#20192)
## Summary

`__class_getitem__` is [implicitly a
classmethod](https://docs.python.org/3/reference/datamodel.html#object.__class_getitem__).

## Test Plan

Added regression test.
2025-09-01 11:22:19 +02:00
David Peter 5518c84ab3
[ty] Support `__init_subclass__` (#20190)
## Summary

`__init_subclass__` is implicitly a classmethod.

closes https://github.com/astral-sh/ty/issues/1106

## Test Plan

Regression test
2025-09-01 10:16:28 +02:00
Carl Meyer 6f2b874d6c
[ty] improve cycle-detection coverage for apply_type_mapping (#20159)
## Summary

Thread visitors through the rest of `apply_type_mapping`: callable and
protocol types.

## Test Plan

Added mdtest that previously stack overflowed.
2025-08-29 16:20:07 -07:00
Carl Meyer 17dc2e4d80
[ty] don't assume that deferred type inference means deferred name resolution (#20160)
## Summary

We have the ability to defer type inference of some parts of
definitions, so as to allow us to create a type that may need to be
recursively referenced in those other parts of the definition.

We also have the ability to do type inference in a context where all
name resolution should be deferred (that is, names should be looked up
from all-reachable-definitions rather than from the location of use.)
This is used for all annotations in stubs, or if `from __future__ import
annotations` is active.

Previous to this PR, these two concepts were linked: deferred-inference
always implied deferred-name-resolution, though we also supported
deferred-name-resolution without deferred-inference, via
`DeferredExpressionState`.

For the upcoming `typing.TypeAlias` support, I will defer inference of
the entire RHS of the alias (so as to support cycles), but that doesn't
imply deferred name resolution; at runtime, the RHS of a name annotated
as `typing.TypeAlias` is executed eagerly.

So this PR fully de-couples the two concepts, instead explicitly setting
the `DeferredExpressionState` in those cases where we should defer name
resolution.

It also fixes a long-standing related bug, where we were deferring name
resolution of all names in class bases, if any of the class bases
contained a stringified annotation.

## Test Plan

Added test that failed before this PR.
2025-08-29 16:19:45 -07:00
Alex Waygood 0bf5d2a204
Revert "[ty] Use `invalid-assignment` error code for invalid assignments to `ClassVar`s" (#20158)
Reverts astral-sh/ruff#20156. As @sharkdp noted in his post-merge
review, there were several issues with that PR that I didn't spot before
merging — but I'm out for four days now, and would rather not leave
things in an inconsistent state for that long. I'll revisit this on
Wednesday.
2025-08-29 19:48:45 +01:00
Carl Meyer 8eb8d25565
[ty] add six ecosystem projects to good.txt (#20157)
## Summary

These projects all check successfully now.

(Pandas still takes 9s, as the comment in `bad.txt` said, but I don't
think this is slow enough to exclude it; mypy-primer overall still runs
in 4 minutes, faster than e.g. the test suite on Windows.)

## Test Plan

mypy-primer CI.
2025-08-29 11:37:29 -07:00
Alex Waygood 9b1b58a451
[ty] Use `invalid-assignment` error code for invalid assignments to `ClassVar`s (#20156)
## Summary

This error is about assigning to attributes rather than reading
attributes, so I think `invalid-assignment` makes more sense than
`invalid-attribute-access`

## Test Plan

existing mdtests updated
2025-08-29 18:43:30 +01:00
Carl Meyer 8223fea062
[ty] ensure union normalization really normalizes (#20147)
## Summary

Now that we have `Type::TypeAlias`, which can wrap a union, and the
possibility of unions including non-unpacked type aliases (which is
necessary to support recursive type aliases), we can no longer assume in
`UnionType::normalized_impl` that normalizing each element of an
existing union will result in a set of elements that we can order and
then place raw into `UnionType` to create a normalized union. It's now
possible for those elements to themselves include union types (unpacked
from an alias). So instead, we need to feed those elements into the full
`UnionBuilder` (with alias-unpacking turned on) to flatten/normalize
them, and then order them.

## Test Plan

Added mdtest.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-08-29 09:02:35 -07:00
Eric Jolibois 5a608f7366
[ty] typecheck dict methods for `TypedDict` (#19874)
## Summary

Typecheck `get()`, `setdefault()`, `pop()` for `TypedDict`

```py
from typing import TypedDict
from typing_extensions import NotRequired

class Employee(TypedDict):
    name: str
    department: NotRequired[str]

emp = Employee(name="Alice", department="Engineering")

emp.get("name")
emp.get("departmen", "Unknown")
emp.pop("department")
emp.pop("name")
```

<img width="838" height="529" alt="Screenshot 2025-08-12 at 11 42 12"
src="https://github.com/user-attachments/assets/77ce150a-223c-4931-b914-551095d8a3a6"
/>


part of https://github.com/astral-sh/ty/issues/154

## Test Plan

Updated Markdown tests

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-08-29 16:25:03 +02:00
Alex Waygood f77315776c
[ty] Better error message for attempting to assign to a read-only property (#20150) 2025-08-29 13:22:23 +00:00
Alex Waygood 04dc223710
[ty] Improve disambiguation of types via fully qualified names (#20141) 2025-08-29 08:44:18 +00:00
Alex Waygood 0d7ed32494
[ty] Enforce that an attribute on a class `X` must be callable in order to satisfy a member on a protocol `P` (#20142)
## Summary

Small, incremental progress towards checking the types of method
members.

## Test Plan

Added an mdtest
2025-08-29 08:31:26 +01:00
Dhruv Manilawala 4ca38b2974
[ty] Unpack variadic argument type in specialization (#20130)
## Summary

This PR fixes various TODOs around overload call when a variadic
argument is used.

The reason this bug existed is because the specialization wouldn't
account for unpacking the type of the variadic argument.

This is fixed by expanding `MatchedArgument` to contain the type of that
argument _only_ when it is a variadic argument. The reason is that
there's a split for when the argument type is inferred -- the
non-variadic arguments are inferred using `infer_argument_types` _after_
parameter matching while the variadic argument type is inferred _during_
the parameter matching. And, the `MatchedArgument` is populated _during_
parameter matching which means the unpacking would need to happen during
parameter matching.

This split seems a bit inconsistent but I don't want to spend a lot of
time on trying to merge them such that all argument type inference
happens in a single place. I might look into it while adding support for
`**kwargs`.

## Test Plan

Update existing tests by resolving the todos.

The ecosystem changes looks correct to me except for the `slice` call
but it seems that it's unrelated to this PR as we infer `slice[Any, Any,
Any]` for a `slice(1, 2, 3)` call on `main` as well
([playground](https://play.ty.dev/9eacce00-c7d5-4dd5-a932-4265cb2bb4f6)).
2025-08-29 04:27:28 +00:00
Carl Meyer 9363eeca26
[ty] add support for cyclic legacy generic protocols (#20125)
## Summary

Just add the necessary Salsa cycle handling.

## Test Plan

Added mdtest.
2025-08-28 16:58:01 +00:00
Carl Meyer f4362b95d7
[ty] add cycle detection for find_legacy_typevars (#20124)
## Summary

Add cycle detection to the `find_legacy_typevars` type method.

## Test Plan

Added mdtest that stack overflowed without this.
2025-08-28 09:55:08 -07:00
David Peter 1842cfe333
[ty] Fix 'too many cycle iterations' for unions of literals (#20137)
## Summary

Decrease the maximum number of literals in a union before we collapse to
the supertype. The better fix for this will be
https://github.com/astral-sh/ty/issues/957, but it is very tempting to
solve this for now by simply decreasing the limit by one, to get below
the salsa limit of 200.

closes https://github.com/astral-sh/ty/issues/660

## Test Plan

Added a regression test that would previously lead to a "too many cycle
iterations" panic.
2025-08-28 16:46:37 +02:00
David Peter b3c4005289
[ty] No boundness analysis for implicit instance attributes (#20128)
## Summary

With this PR, we stop performing boundness analysis for implicit
instance attributes:

```py
class C:
    def __init__(self):
        if False:   
            self.x = 1

C().x  # would previously show an error, with this PR we pretend the attribute exists
```

This PR is potentially just a temporary measure until we find a better
fix. But I have already invested a lot of time trying to find the root
cause of https://github.com/astral-sh/ty/issues/758 (and [this
example](https://github.com/astral-sh/ty/issues/758#issuecomment-3206108262),
which I'm not entirely sure is related) and I still don't understand
what is going on. This PR fixes the performance problems in both of
these problems (in a rather crude way).

The impact of the proposed change on the ecosystem is small, and the
three new diagnostics are arguably true positives (previously hidden
because we considered the code unreachable, based on e.g. `assert`ions
that depended on implicit instance attributes). So this seems like a
reasonable fix for now.

Note that we still support cases like these:

```py
class D:
    if False:  # or any other expression that statically evaluates to `False`
        x: int = 1

D().x  # still an error


class E:
    if False:  # or any other expression that statically evaluates to `False`
        def f(self):
            self.x = 1

E().x  # still an error
```

closes https://github.com/astral-sh/ty/issues/758

## Test Plan

Updated tests, benchmark results
2025-08-28 16:25:07 +02:00
Shaygan Hooshyari d9aaacd01f
[ty] Evaluate reachability of non-definitely-bound to Ambiguous (#19579)
## Summary

closes https://github.com/astral-sh/ty/issues/692

If the expression (or any child expressions) is not definitely bound the
reachability constraint evaluation is determined as ambiguous.

This fixes the infinite cycles panic in the following code:

```py
from typing import Literal

class Toggle:
    def __init__(self: "Toggle"):
        if not self.x:
            self.x: Literal[True] = True
```

Credit of this solution is for David.

## Test Plan

- Added a test case with too many cycle iterations panic.
- Previous tests.

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-08-28 14:34:49 +02:00
Jelle Zijlstra 18eaa659c1
[ty] Introduce a representation for the top/bottom materialization of an invariant generic (#20076)
Part of #994. This adds a new field to the Specialization struct to
record when we're dealing with the top or bottom materialization of an
invariant generic. It also implements subtyping and assignability for
these objects.

Next planned steps after this is done are to implement other operations
on top/bottom materializations; probably attribute access is an
important one.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-08-27 17:53:57 -07:00
Leandro Braga d75ef3823c
[ty] print diagnostics with fully qualified name to disambiguate some cases (#19850)
There are some situations that we have a confusing diagnostics due to
identical class names.

## Class with same name from different modules

```python
import pandas
import polars

df: pandas.DataFrame = polars.DataFrame()
```

This yields the following error:

**Actual:**
error: [invalid-assignment] "Object of type `DataFrame` is not
assignable to `DataFrame`"
**Expected**:
error: [invalid-assignment] "Object of type `polars.DataFrame` is not
assignable to `pandas.DataFrame`"

## Nested classes

```python
from enum import Enum

class A:
    class B(Enum):
        ACTIVE = "active"
        INACTIVE = "inactive"

class C:
    class B(Enum):
        ACTIVE = "active"
        INACTIVE = "inactive"
```

**Actual**:
error: [invalid-assignment] "Object of type `Literal[B.ACTIVE]` is not
assignable to `B`"
**Expected**:
error: [invalid-assignment] "Object of type
`Literal[my_module.C.B.ACTIVE]` is not assignable to `my_module.A.B`"

## Solution

In this MR we added an heuristics to detect when to use a fully
qualified name:
- There is an invalid assignment and;
- They are two different classes and;
- They have the same name

The fully qualified name always includes:
- module name
- nested classes name
- actual class name

There was no `QualifiedDisplay` so I had to implement it from scratch.
I'm very new to the codebase, so I might have done things inefficiently,
so I appreciate feedback.

Should we pre-compute the fully qualified name or do it on demand? 

## Not implemented

### Function-local classes

Should we approach this in a different PR?

**Example**:
```python 
# t.py
from __future__ import annotations


def function() -> A:
    class A:
        pass

    return A()


class A:
    pass


a: A = function()
```

#### mypy

```console
t.py:8: error: Incompatible return value type (got "t.A@5", expected "t.A")  [return-value]
```

From my testing the 5 in `A@5` comes from the like number. 

#### ty

```console
error[invalid-return-type]: Return type does not match returned value
 --> t.py:4:19
  |
4 | def function() -> A:
  |                   - Expected `A` because of return type
5 |     class A:
6 |         pass
7 |
8 |     return A()
  |            ^^^ expected `A`, found `A`
  |
info: rule `invalid-return-type` is enabled by default
```

Fixes https://github.com/astral-sh/ty/issues/848

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
2025-08-27 20:46:07 +00:00
David Peter 0b3548755c
[ty] Preserve qualifiers when accessing attributes on unions/intersections (#20114)
## Summary

Properly preserve type qualifiers when accessing attributes on unions
and intersections. This is a prerequisite for
https://github.com/astral-sh/ruff/pull/19579.

Also fix a completely wrong implementation of
`map_with_boundness_and_qualifiers`. It now closely follows
`map_with_boundness` (just above).

## Test Plan

I thought about it, but didn't find any easy way to test this. This only
affected `Type::member`. Things like validation of attribute writes
(where type qualifiers like `ClassVar` and `Final` are important) were
already handling things correctly.
2025-08-27 20:01:45 +02:00
Alex Waygood ce1dc21e7e
[ty] Fix the inferred interface of specialized generic protocols (#19866) 2025-08-27 18:16:15 +01:00
Alex Waygood 7d0c8e045c
[ty] Infer slightly more precise types for comprehensions (#20111) 2025-08-27 13:21:47 +01:00
Alex Waygood d71518b369
[ty] Add more tests for protocols (#20095)
Co-authored-by: Shunsuke Shibayama <sbym1346@gmail.com>
2025-08-27 12:56:14 +01:00
Carl Meyer 9ab276b345
[ty] don't eagerly unpack aliases in user-authored unions (#20055)
## Summary

Add a subtly different test case for recursive PEP 695 type aliases,
which does require that we relax our union simplification, so we don't
eagerly unpack aliases from user-provided union annotations.

## Test Plan

Added mdtest.
2025-08-26 16:29:45 -07:00
Renkai Ge 73720c73be
[ty] Add search paths info to unresolved import diagnostics (#20040)
Fixes https://github.com/astral-sh/ty/issues/457

---------

Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
2025-08-26 11:01:16 -04:00
Dylan ef4897f9f3
[ty] Add support for PEP 750 t-strings (#20085)
This PR attempts to adds support for inferring`string.templatelib.Template` for t-string literals.
2025-08-25 18:49:49 +00:00
Alex Waygood ecf3c4ca11
[ty] Add support for PEP 800 (#20084) 2025-08-25 19:39:05 +01:00
Carl Meyer 33c5f6f4f8
[ty] don't mark entire type-alias scopes as Deferred (#20086)
## Summary

This has been here for awhile (since our initial PEP 695 type alias
support) but isn't really correct. The right-hand-side of a PEP 695 type
alias is a distinct scope, and we don't mark it as an "eager" nested
scope, so it automatically gets "deferred" resolution of names from
outer scopes (just like a nested function). Thus it's
redundant/unnecessary for us to use `DeferredExpressionState::Deferred`
for resolving that RHS expression -- that's for deferring resolution of
individual names within a scope. Using it here causes us to wrongly
ignore applicable outer-scope narrowing.

## Test Plan

Added mdtest that failed before this PR (the second snippet -- the first
snippet always passed.)
2025-08-25 11:32:18 -07:00
github-actions[bot] ba47010150
[ty] Sync vendored typeshed stubs (#20083)
Co-authored-by: typeshedbot <>
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
2025-08-25 17:01:51 +00:00
Alex Waygood a04823cfad
[ty] Completely ignore typeshed's stub for `Any` (#20079) 2025-08-25 15:27:55 +01:00
Eric Jolibois f9bbee33f6
[ty] validate constructor call of `TypedDict` (#19810)
## Summary
Implement validation for `TypedDict` constructor calls and dictionary
literal assignments, including support for `total=False` and proper
field management.
Also add support for `Required` and `NotRequired` type qualifiers in
`TypedDict` classes, along with proper inheritance behavior and the
`total=` parameter.
Support both constructor calls and dict literal syntax

part of https://github.com/astral-sh/ty/issues/154

### Basic Required Field Validation
```py
class Person(TypedDict):
    name: str
    age: int | None

# Error: Missing required field 'name' in TypedDict `Person` constructor
incomplete = Person(age=25)

# Error: Invalid argument to key "name" with declared type `str` on TypedDict `Person`
wrong_type = Person(name=123, age=25)

# Error: Invalid key access on TypedDict `Person`: Unknown key "extra"
extra_field = Person(name="Bob", age=25, extra=True)
```
<img width="773" height="191" alt="Screenshot 2025-08-07 at 17 59 22"
src="https://github.com/user-attachments/assets/79076d98-e85f-4495-93d6-a731aa72a5c9"
/>

### Support for `total=False`
```py
class OptionalPerson(TypedDict, total=False):
    name: str
    age: int | None

# All valid - all fields are optional with total=False
charlie = OptionalPerson()
david = OptionalPerson(name="David")
emily = OptionalPerson(age=30)
frank = OptionalPerson(name="Frank", age=25)

# But type validation and extra fields still apply
invalid_type = OptionalPerson(name=123)  # Error: Invalid argument type
invalid_extra = OptionalPerson(extra=True)  # Error: Invalid key access
```

### Dictionary Literal Validation
```py
# Type checking works for both constructors and dict literals
person: Person = {"name": "Alice", "age": 30}

reveal_type(person["name"])  # revealed: str
reveal_type(person["age"])   # revealed: int | None

# Error: Invalid key access on TypedDict `Person`: Unknown key "non_existing"
reveal_type(person["non_existing"])  # revealed: Unknown
```

### `Required`, `NotRequired`, `total`
```python
from typing import TypedDict
from typing_extensions import Required, NotRequired

class PartialUser(TypedDict, total=False):
    name: Required[str]      # Required despite total=False
    age: int                 # Optional due to total=False
    email: NotRequired[str]  # Explicitly optional (redundant)

class User(TypedDict):
    name: Required[str]      # Explicitly required (redundant)
    age: int                 # Required due to total=True
    bio: NotRequired[str]    # Optional despite total=True

# Valid constructions
partial = PartialUser(name="Alice")  # name required, age optional
full = User(name="Bob", age=25)      # name and age required, bio optional

# Inheritance maintains original field requirements
class Employee(PartialUser):
    department: str                  # Required (new field)
    # name: still Required (inherited)
    # age: still optional (inherited)

emp = Employee(name="Charlie", department="Engineering")  # 
Employee(department="Engineering")  # 
e: Employee = {"age": 1}  # 
```

<img width="898" height="683" alt="Screenshot 2025-08-11 at 22 02 57"
src="https://github.com/user-attachments/assets/4c1b18cd-cb2e-493a-a948-51589d121738"
/>

## Implementation
The implementation reuses existing validation logic done in
https://github.com/astral-sh/ruff/pull/19782

### ℹ️ Why I did NOT synthesize an `__init__` for `TypedDict`:

`TypedDict` inherits `dict.__init__(self, *args, **kwargs)` that accepts
all arguments.
The type resolution system finds this inherited signature **before**
looking for synthesized members.
So `own_synthesized_member()` is never called because a signature
already exists.

To force synthesis, you'd have to override Python’s inheritance
mechanism, which would break compatibility with the existing ecosystem.

This is why I went with ad-hoc validation. IMO it's the only viable
approach that respects Python’s
inheritance semantics while providing the required validation.

### Refacto of `Field`

**Before:**
```rust
struct Field<'db> {
    declared_ty: Type<'db>,
    default_ty: Option<Type<'db>>,     // NamedTuple and dataclass only
    init_only: bool,                   // dataclass only  
    init: bool,                        // dataclass only
    is_required: Option<bool>,         // TypedDict only
}
```

**After:**
```rust
struct Field<'db> {
    declared_ty: Type<'db>,
    kind: FieldKind<'db>,
}

enum FieldKind<'db> {
    NamedTuple { default_ty: Option<Type<'db>> },
    Dataclass { default_ty: Option<Type<'db>>, init_only: bool, init: bool },
    TypedDict { is_required: bool },
}
```

## Test Plan
Updated Markdown tests

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-08-25 14:45:52 +02:00
Dhruv Manilawala 376e3ff395
[ty] Limit argument expansion size for overload call evaluation (#20041)
## Summary

This PR limits the argument type expansion size for an overload call
evaluation to 512.

The limit chosen is arbitrary but I've taken the 256 limit from Pyright
into account and bumped it x2 to start with.

Initially, I actually started out by trying to refactor the entire
argument type expansion to be lazy. Currently, expanding a single
argument at any position eagerly creates the combination (argument
lists) and returns that (`Vec<CallArguments>`) but I thought we could
make it lazier by converting the return type of `expand` from
`Iterator<Item = Vec<CallArguments>>` to `Iterator<Item = Iterator<Item
= CallArguments>>` but that's proving to be difficult to implement
mainly because we **need** to maintain the previous expansion to
generate the next expansion which is the main reason to use
`std::iter::successors` in the first place.

Another approach would be to eagerly expand all the argument types and
then use the `combinations` from `itertools` to generate the
combinations but we would need to find the "boundary" between arguments
lists produced from expanding argument at position 1 and position 2
because that's important for the algorithm.

Closes: https://github.com/astral-sh/ty/issues/868

## Test Plan

Add test case to demonstrate the limit along with the diagnostic
snapshot stating that the limit has been reached.
2025-08-25 09:43:04 +00:00
Jelle Zijlstra ec86a4e960
[ty] Add Top[] and Bottom[] special forms, replacing top_materialization_of() function (#20054)
Part of astral-sh/ty#994

## Summary

Add new special forms to `ty_extensions`, `Top[T]` and `Bottom[T]`.
Remove `ty_extensions.top_materialization` and
`ty_extensions.bottom_materialization`.

## Test Plan

Converted the existing `materialization.md` mdtest to the new syntax.
Added some tests for invalid use of the new special form.
2025-08-23 11:20:56 -07:00
Alex Waygood bc6ea68733
[ty] Add precise iteration and unpacking inference for string literals and bytes literals (#20023)
## Summary

Previously we held off from doing this because we weren't sure that it
was worth the added complexity cost. But our code has changed in the
months since we made that initial decision, and I think the structure of
the code is such that it no longer really leads to much added complexity
to add precise inference when unpacking a string literal or a bytes
literal.

The improved inference we gain from this has real benefits to users (see
the mypy_primer report), and this PR doesn't appear to have a
performance impact.

## Test plan

mdtests
2025-08-22 19:33:08 +01:00
github-actions[bot] 7a44ea680e
[ty] Sync vendored typeshed stubs (#20031)
Co-authored-by: typeshedbot <>
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
2025-08-21 21:32:48 +00:00
Alex Waygood f82025d919
[ty] Improve diagnostics for bad calls to functions (#20022) 2025-08-21 22:00:44 +01:00
Douglas Creager 14fe1228e7
[ty] Perform assignability etc checks using new `Constraints` trait (#19838)
"Why would you do this? This looks like you just replaced `bool` with an
overly complex trait"

Yes that's correct!

This should be a no-op refactoring. It replaces all of the logic in our
assignability, subtyping, equivalence, and disjointness methods to work
over an arbitrary `Constraints` trait instead of only working on `bool`.

The methods that `Constraints` provides looks very much like what we get
from `bool`. But soon we will add a new impl of this trait, and some new
methods, that let us express "fuzzy" constraints that aren't always true
or false. (In particular, a constraint will express the upper and lower
bounds of the allowed specializations of a typevar.)

Even once we have that, most of the operations that we perform on
constraint sets will be the usual boolean operations, just on sets.
(`false` becomes empty/never; `true` becomes universe/always; `or`
becomes union; `and` becomes intersection; `not` becomes negation.) So
it's helpful to have this separate PR to refactor how we invoke those
operations without introducing the new functionality yet.

Note that we also have translations of `Option::is_some_and` and
`is_none_or`, and of `Iterator::any` and `all`, and that the `and`,
`or`, `when_any`, and `when_all` methods are meant to short-circuit,
just like the corresponding boolean operations. For constraint sets,
that depends on being able to implement the `is_always` and `is_never`
trait methods.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-08-21 09:30:09 -04:00
Dhruv Manilawala d43a3d34dd
[ty] Avoid unnecessary argument type expansion (#19999)
## Summary

Part of: https://github.com/astral-sh/ty/issues/868

This PR adds a heuristic to avoid argument type expansion if it's going
to eventually lead to no matching overload.

This is done by checking whether the non-expandable argument types are
assignable to the corresponding annotated parameter type. If one of them
is not assignable to all of the remaining overloads, then argument type
expansion isn't going to help.

## Test Plan

Add mdtest that would otherwise take a long time because of the number
of arguments that it would need to expand (30).
2025-08-21 06:13:11 +00:00
Aria Desires 99111961c0
[ty] Add link for namespaces being partial (#20015)
As requested
2025-08-20 21:28:57 -07:00
Leandro Braga 39ee71c2a5
[ty] correctly ignore field specifiers when not specified (#20002)
This commit corrects the type checker's behavior when handling
`dataclass_transform` decorators that don't explicitly specify
`field_specifiers`. According to [PEP 681 (Data Class
Transforms)](https://peps.python.org/pep-0681/#dataclass-transform-parameters),
when `field_specifiers` is not provided, it defaults to an empty tuple,
meaning no field specifiers are supported and
`dataclasses.field`/`dataclasses.Field` calls should be ignored.

Fixes https://github.com/astral-sh/ty/issues/980
2025-08-20 11:33:23 -07:00
Dhruv Manilawala f019cfd15f
[ty] Use specialized parameter type for overload filter (#19964)
## Summary

Closes: https://github.com/astral-sh/ty/issues/669

(This turned out to be simpler that I thought :))

## Test Plan

Update existing test cases.

### Ecosystem report

Most of them are basically because ty has now started inferring more
precise types for the return type to an overloaded call and a lot of the
types are defined using type aliases, here's some examples:

<details><summary>Details</summary>
<p>

> attrs (https://github.com/python-attrs/attrs)
> + tests/test_make.py:146:14: error[unresolved-attribute] Type
`Literal[42]` has no attribute `default`
> - Found 555 diagnostics
> + Found 556 diagnostics

This is accurate now that we infer the type as `Literal[42]` instead of
`Unknown` (Pyright infers it as `int`)

> optuna (https://github.com/optuna/optuna)
> + optuna/_gp/search_space.py:181:53: error[invalid-argument-type]
Argument to function `_round_one_normalized_param` is incorrect:
Expected `tuple[int | float, int | float]`, found `tuple[Unknown |
ndarray[Unknown, <class 'float'>], Unknown | ndarray[Unknown, <class
'float'>]]`
> + optuna/_gp/search_space.py:181:83: error[invalid-argument-type]
Argument to function `_round_one_normalized_param` is incorrect:
Expected `int | float`, found `Unknown | ndarray[Unknown, <class
'float'>]`
> + tests/gp_tests/test_search_space.py:109:13:
error[invalid-argument-type] Argument to function
`_unnormalize_one_param` is incorrect: Expected `tuple[int | float, int
| float]`, found `Unknown | ndarray[Unknown, <class 'float'>]`
> + tests/gp_tests/test_search_space.py:110:13:
error[invalid-argument-type] Argument to function
`_unnormalize_one_param` is incorrect: Expected `int | float`, found
`Unknown | ndarray[Unknown, <class 'float'>]`
> - Found 559 diagnostics
> + Found 563 diagnostics

Same as above where ty is now inferring a more precise type like
`Unknown | ndarray[tuple[int, int], <class 'float'>]` instead of just
`Unknown` as before

> jinja (https://github.com/pallets/jinja)
> + src/jinja2/bccache.py:298:39: error[invalid-argument-type] Argument
to bound method `write_bytecode` is incorrect: Expected `IO[bytes]`,
found `_TemporaryFileWrapper[str]`
> - Found 186 diagnostics
> + Found 187 diagnostics

This requires support for type aliases to match the correct overload.

> hydra-zen (https://github.com/mit-ll-responsible-ai/hydra-zen)
> + src/hydra_zen/wrapper/_implementations.py:945:16:
error[invalid-return-type] Return type does not match returned value:
expected `DataClass_ | type[@Todo(type[T] for protocols)] | ListConfig |
DictConfig`, found `@Todo(unsupported type[X] special form) | (((...) ->
Any) & dict[Unknown, Unknown]) | (DataClass_ & dict[Unknown, Unknown]) |
dict[Any, Any] | (ListConfig & dict[Unknown, Unknown]) | (DictConfig &
dict[Unknown, Unknown]) | (((...) -> Any) & list[Unknown]) | (DataClass_
& list[Unknown]) | list[Any] | (ListConfig & list[Unknown]) |
(DictConfig & list[Unknown])`
> + tests/annotations/behaviors.py:60:28: error[call-non-callable]
Object of type `Path` is not callable
> + tests/annotations/behaviors.py:64:21: error[call-non-callable]
Object of type `Path` is not callable
> + tests/annotations/declarations.py:167:17: error[call-non-callable]
Object of type `Path` is not callable
> + tests/annotations/declarations.py:524:17:
error[unresolved-attribute] Type `<class 'int'>` has no attribute
`_target_`
> - Found 561 diagnostics
> + Found 566 diagnostics

Same as above, this requires support for type aliases to match the
correct overload.

> paasta (https://github.com/yelp/paasta)
> + paasta_tools/utils.py:4188:19: warning[redundant-cast] Value is
already of type `list[str]`
> - Found 888 diagnostics
> + Found 889 diagnostics

This is correct.

> colour (https://github.com/colour-science/colour)
> + colour/plotting/diagrams.py:448:13: error[invalid-argument-type]
Argument to bound method `__init__` is incorrect: Expected
`Sequence[@Todo(Support for `typing.TypeAlias`)]`, found
`ndarray[tuple[int, int, int], dtype[Unknown]]`
> + colour/plotting/diagrams.py:462:13: error[invalid-argument-type]
Argument to bound method `__init__` is incorrect: Expected
`Sequence[@Todo(Support for `typing.TypeAlias`)]`, found
`ndarray[tuple[int, int, int], dtype[Unknown]]`
> + colour/plotting/models.py:419:13: error[invalid-argument-type]
Argument to bound method `__init__` is incorrect: Expected
`Sequence[@Todo(Support for `typing.TypeAlias`)]`, found
`ndarray[tuple[int, int, int], dtype[Unknown]]`
> + colour/plotting/temperature.py:230:9: error[invalid-argument-type]
Argument to bound method `__init__` is incorrect: Expected
`Sequence[@Todo(Support for `typing.TypeAlias`)]`, found
`ndarray[tuple[int, int, int], dtype[Unknown]]`
> + colour/plotting/temperature.py:474:13: error[invalid-argument-type]
Argument to bound method `__init__` is incorrect: Expected
`Sequence[@Todo(Support for `typing.TypeAlias`)]`, found
`ndarray[tuple[int, int, int], dtype[Unknown]]`
> + colour/plotting/temperature.py:495:17: error[invalid-argument-type]
Argument to bound method `__init__` is incorrect: Expected
`Sequence[@Todo(Support for `typing.TypeAlias`)]`, found
`ndarray[tuple[int, int, int], dtype[Unknown]]`
> + colour/plotting/temperature.py:513:13: error[invalid-argument-type]
Argument to bound method `text` is incorrect: Expected `int | float`,
found `ndarray[@Todo(Support for `typing.TypeAlias`), dtype[Unknown]]`
> + colour/plotting/temperature.py:514:13: error[invalid-argument-type]
Argument to bound method `text` is incorrect: Expected `int | float`,
found `ndarray[@Todo(Support for `typing.TypeAlias`), dtype[Unknown]]`
> - Found 480 diagnostics
> + Found 488 diagnostics

Most of them are correct except for the last two diagnostics which I'm
not sure
what's happening, it's trying to index into an `np.ndarray` type (which
is
inferred correctly) but I think it might be picking up an incorrect
overload
for the `__getitem__` method.

Scipy's diagnostics also requires support for type alises to pick the
correct overload.

</p>
</details>
2025-08-20 09:39:05 +05:30
Eric Mark Martin 33030b34cd
[ty] linear variance inference for PEP-695 type parameters (#18713)
## Summary

Implement linear-time variance inference for type variables
(https://github.com/astral-sh/ty/issues/488).

Inspired by Martin Huschenbett's [PyCon 2025
Talk](https://www.youtube.com/watch?v=7uixlNTOY4s&t=9705s).

## Test Plan

update tests, add new tests, including for mutually recursive classes

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-08-19 17:54:09 -07:00
Alex Waygood 656fc335f2
[ty] Strict validation of protocol members (#17750) 2025-08-19 22:45:41 +00:00
Alex Waygood 662d18bd05
[ty] Add precise inference for unpacking a TypeVar if the TypeVar has an upper bound with a precise tuple spec (#19985) 2025-08-19 22:11:30 +01:00
Aria Desires c82e255ca8
[ty] Fix namespace packages that behave like partial stubs (#19994)
In implementing partial stubs I had observed that this continue in the
namespace package code seemed erroneous since the same continue for
partial stubs didn't work. Unfortunately I wasn't confident enough to
push on that hunch. Fortunately I remembered that hunch to make this an
easy fix.

The issue with the continue is that it bails out of the current
search-path without testing any .py files. This breaks when for example
`google` and `google-stubs`/`types-google` are both in the same
site-packages dir -- failing to find a module in `types-google` has us
completely skip over `google`!

Fixes https://github.com/astral-sh/ty/issues/520
2025-08-19 16:34:39 -04:00
Eric Jolibois 58efd19f11
[ty] apply `KW_ONLY` sentinel only to local fields (#19986)
fix https://github.com/astral-sh/ty/issues/1047

## Summary

This PR fixes how `KW_ONLY` is applied in dataclasses. Previously, the
sentinel leaked into subclasses and incorrectly marked their fields as
keyword-only; now it only affects fields declared in the same class.

```py
from dataclasses import dataclass, KW_ONLY

@dataclass
class D:
    x: int
    _: KW_ONLY
    y: str

@dataclass
class E(D):
    z: bytes

# This should work: x=1 (positional), z=b"foo" (positional), y="foo" (keyword-only)
E(1, b"foo", y="foo")

reveal_type(E.__init__)  # revealed: (self: E, x: int, z: bytes, *, y: str) -> None
```

<!-- What's the purpose of the change? What does it do, and why? -->

## Test Plan

<!-- How was it tested? -->
mdtests
2025-08-19 11:01:35 -07:00
Alex Waygood e5c091b850
[ty] Fix protocol interface inference for stub protocols and subprotocols (#19950) 2025-08-19 10:31:11 +00:00
Alex Waygood 4242905b36
[ty] Detect `NamedTuple` classes where fields without default values follow fields with default values (#19945) 2025-08-19 08:56:08 +00:00
Carl Meyer a04375173c
[ty] fix unpacking a type alias with detailed tuple spec (#19981)
## Summary

Fixes https://github.com/astral-sh/ty/issues/1046

We special-case iteration of certain types because they may have a more
detailed tuple-spec. Now that type aliases are a distinct type variant,
we need to handle them as well.

I don't love that `Type::TypeAlias` means we have to remember to add a
case for it basically anywhere we are special-casing a certain kind of
type, but at the moment I don't have a better plan. It's another
argument for avoiding fallback cases in `Type` matches, which we usually
prefer; I've updated this match statement to be comprehensive.

## Test Plan

Added mdtest.
2025-08-18 17:54:05 -07:00
Alex Waygood e6dcdd29f2
[ty] Add a Todo-type branch for `type[P]` where `P` is a protocol class (#19947) 2025-08-18 20:38:19 +00:00
Matthew Mckee 24f6d2dc13
[ty] Infer the correct type of Enum `__eq__` and `__ne__` comparisions (#19666)
## Summary

Resolves https://github.com/astral-sh/ty/issues/920

## Test Plan

Update `enums.md`

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-08-18 19:45:44 +02:00
Alex Waygood 3314cf90ed
[ty] Add more regression tests for `tuple` (#19974) 2025-08-18 18:30:05 +01:00
Aria Desires 0cb1abc1fc
[ty] Implement partial stubs (#19931)
Fixes https://github.com/astral-sh/ty/issues/184
2025-08-18 13:14:13 -04:00
Alex Waygood fbf24be8ae
[ty] Detect illegal multiple inheritance with `NamedTuple` (#19943) 2025-08-18 12:03:01 +00:00