Commit Graph

137 Commits

Author SHA1 Message Date
Andrew Gallant 8647844572 [ty] Adjust scope completions to use all reachable symbols
Fixes astral-sh/ty#1294
2025-12-11 08:26:15 -05:00
Andrew Gallant c1c45a6a13 [ty] Remove `all_` prefix from some routines on UseDefMap
These routines don't return *all* symbols/members, but rather,
only *for* a particular scope. We do specifically want to add
some routines that return *all* symbols/members, and this naming
scheme made that confusing. It was also inconsistent with other
routines like `all_end_of_scope_symbol_declarations` which *do*
return *all* symbols.
2025-12-11 08:26:15 -05:00
Aria Desires 45ac30a4d7
[ty] Teach `ty` the meaning of desperation (try ancestor `pyproject.toml`s as search-paths if module resolution fails) (#21745)
## Summary

This makes an importing file a required argument to module resolution,
and if the fast-path cached query fails to resolve the module, take the
slow-path uncached (could be cached if we want)
`desperately_resolve_module` which will walk up from the importing file
until it finds a `pyproject.toml` (arbitrary decision, we could try
every ancestor directory), at which point it takes one last desperate
attempt to use that directory as a search-path. We do not continue
walking up once we've found a `pyproject.toml` (arbitrary decision, we
could keep going up).

Running locally, this fixes every broken-for-workspace-reasons import in
pyx's workspace!

* Fixes https://github.com/astral-sh/ty/issues/1539
* Improves https://github.com/astral-sh/ty/issues/839

## Test Plan

The workspace tests see a huge improvement on most absolute imports.
2025-12-03 15:04:36 -05:00
David Peter 1f4f8d9950
[ty] Fix flow of associated member states during star imports (#21776)
## Summary

Star-imports can not just affect the state of symbols that they pull in,
they can also affect the state of members that are associated with those
symbols. For example, if `obj.attr` was previously narrowed from `int |
None` to `int`, and a star-import now overwrites `obj`, then the
narrowing on `obj.attr` should be "reset".

This PR keeps track of the state of associated members during star
imports and properly models the flow of their corresponding state
through the control flow structure that we artificially create for
star-imports.

See [this
comment](https://github.com/astral-sh/ty/issues/1355#issuecomment-3607125005)
for an explanation why this caused ty to see certain `asyncio` symbols
as not being accessible on Python 3.14.

closes https://github.com/astral-sh/ty/issues/1355

## Ecosystem impact

```diff
async-utils (https://github.com/mikeshardmind/async-utils)
- src/async_utils/bg_loop.py:115:31: error[invalid-argument-type] Argument to bound method `set_task_factory` is incorrect: Expected `_TaskFactory | None`, found `def eager_task_factory[_T_co](loop: AbstractEventLoop | None, coro: Coroutine[Any, Any, _T_co@eager_task_factory], *, name: str | None = None, context: Context | None = None) -> Task[_T_co@eager_task_factory]`
- Found 30 diagnostics
+ Found 29 diagnostics

mitmproxy (https://github.com/mitmproxy/mitmproxy)
+ mitmproxy/utils/asyncio_utils.py:96:60: warning[unused-ignore-comment] Unused blanket `type: ignore` directive
- test/conftest.py:37:31: error[invalid-argument-type] Argument to bound method `set_task_factory` is incorrect: Expected `_TaskFactory | None`, found `def eager_task_factory[_T_co](loop: AbstractEventLoop | None, coro: Coroutine[Any, Any, _T_co@eager_task_factory], *, name: str | None = None, context: Context | None = None) -> Task[_T_co@eager_task_factory]`
```

All of these seem to be correct, they give us a different type for
`asyncio` symbols that are now imported from different
`sys.version_info` branches (where we previously failed to recognize
some of these as statically true/false).

```diff
dd-trace-py (https://github.com/DataDog/dd-trace-py)
- ddtrace/contrib/internal/asyncio/patch.py:39:12: error[invalid-argument-type] Argument to function `unwrap` is incorrect: Expected `WrappedFunction`, found `def create_task[_T](self, coro: Coroutine[Any, Any, _T@create_task] | Generator[Any, None, _T@create_task], *, name: object = None) -> Task[_T@create_task]`
+ ddtrace/contrib/internal/asyncio/patch.py:39:12: error[invalid-argument-type] Argument to function `unwrap` is incorrect: Expected `WrappedFunction`, found `def create_task[_T](self, coro: Generator[Any, None, _T@create_task] | Coroutine[Any, Any, _T@create_task], *, name: object = None) -> Task[_T@create_task]`
```

Similar, but only results in a diagnostic change.

## Test Plan

Added a regression test
2025-12-03 17:52:31 +01:00
David Peter d6e472f297
[ty] Reachability constraints: minor documentation fixes (#21774) 2025-12-03 16:40:11 +01:00
Brent Westbrook 2250fa6f98
Fix syntax error false positives for `await` outside functions (#21763)
## Summary

Fixes #21750 and a related bug in `PLE1142`. We were not properly
considering generators to be valid `await` contexts, which caused the
`F704` issue. One of the tests I added for this also uncovered an issue
in `PLE1142` for comprehensions nested within async generators because
we were only checking the current scope rather than traversing the
nested context.

## Test Plan

Both of these rules are implemented as semantic syntax errors, so I
added tests (and fixes) in both Ruff and ty.
2025-12-02 21:02:02 +00:00
Micha Reiser 644096ea8a
[ty] Fix find-references for import aliases (#21736) 2025-12-02 14:37:50 +01:00
David Peter 5358ddae88
[ty] Exhaustiveness checking for generic classes (#21726)
## Summary

We had tests for this already, but they used generic classes that were
bivariant in their type parameter, and so this case wasn't captured.

closes https://github.com/astral-sh/ty/issues/1702

## Test Plan

Updated Markdown tests
2025-12-01 13:52:36 +01:00
David Peter 42f152108a
[ty] Generic types aliases (implicit and PEP 613) (#21553)
## Summary

Add support for generic PEP 613 type aliases and generic implicit type
aliases:
```py
from typing import TypeVar

T = TypeVar("T")
ListOrSet = list[T] | set[T]

def _(xs: ListOrSet[int]):
    reveal_type(xs)  # list[int] | set[int]
```

closes https://github.com/astral-sh/ty/issues/1643
closes https://github.com/astral-sh/ty/issues/1629
closes https://github.com/astral-sh/ty/issues/1596
closes https://github.com/astral-sh/ty/issues/573
closes https://github.com/astral-sh/ty/issues/221

## Typing conformance

```diff
-aliases_explicit.py:52:5: error[type-assertion-failure] Type `list[int]` does not match asserted type `@Todo(specialized generic alias in type expression)`
-aliases_explicit.py:53:5: error[type-assertion-failure] Type `tuple[str, ...] | list[str]` does not match asserted type `@Todo(Generic specialization of types.UnionType)`
-aliases_explicit.py:54:5: error[type-assertion-failure] Type `tuple[int, int, int, str]` does not match asserted type `@Todo(specialized generic alias in type expression)`
-aliases_explicit.py:56:5: error[type-assertion-failure] Type `(int, str, /) -> str` does not match asserted type `@Todo(Generic specialization of typing.Callable)`
-aliases_explicit.py:59:5: error[type-assertion-failure] Type `int | str | None | list[list[int]]` does not match asserted type `int | str | None | list[@Todo(specialized generic alias in type expression)]`
```

New true negatives ✔️ 

```diff
+aliases_explicit.py:41:36: error[invalid-type-arguments] Too many type arguments: expected 1, got 2
-aliases_explicit.py:57:5: error[type-assertion-failure] Type `(int, str, str, /) -> None` does not match asserted type `@Todo(Generic specialization of typing.Callable)`
+aliases_explicit.py:57:5: error[type-assertion-failure] Type `(int, str, str, /) -> None` does not match asserted type `(...) -> Unknown`
```

These require `ParamSpec`

```diff
+aliases_explicit.py:67:24: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
+aliases_explicit.py:68:24: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
+aliases_explicit.py:69:29: error[invalid-type-arguments] Too many type arguments: expected 1, got 2
+aliases_explicit.py:70:29: error[invalid-type-arguments] Too many type arguments: expected 1, got 2
+aliases_explicit.py:71:29: error[invalid-type-arguments] Too many type arguments: expected 1, got 2
+aliases_explicit.py:102:20: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
```

New true positives ✔️ 

```diff
-aliases_implicit.py:63:5: error[type-assertion-failure] Type `list[int]` does not match asserted type `@Todo(specialized generic alias in type expression)`
-aliases_implicit.py:64:5: error[type-assertion-failure] Type `tuple[str, ...] | list[str]` does not match asserted type `@Todo(Generic specialization of types.UnionType)`
-aliases_implicit.py:65:5: error[type-assertion-failure] Type `tuple[int, int, int, str]` does not match asserted type `@Todo(specialized generic alias in type expression)`
-aliases_implicit.py:67:5: error[type-assertion-failure] Type `(int, str, /) -> str` does not match asserted type `@Todo(Generic specialization of typing.Callable)`
-aliases_implicit.py:70:5: error[type-assertion-failure] Type `int | str | None | list[list[int]]` does not match asserted type `int | str | None | list[@Todo(specialized generic alias in type expression)]`
-aliases_implicit.py:71:5: error[type-assertion-failure] Type `list[bool]` does not match asserted type `@Todo(specialized generic alias in type expression)`
```

New true negatives ✔️ 

```diff
+aliases_implicit.py:54:36: error[invalid-type-arguments] Too many type arguments: expected 1, got 2
-aliases_implicit.py:68:5: error[type-assertion-failure] Type `(int, str, str, /) -> None` does not match asserted type `@Todo(Generic specialization of typing.Callable)`
+aliases_implicit.py:68:5: error[type-assertion-failure] Type `(int, str, str, /) -> None` does not match asserted type `(...) -> Unknown`
```

These require `ParamSpec`

```diff
+aliases_implicit.py:76:24: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
+aliases_implicit.py:77:24: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
+aliases_implicit.py:78:29: error[invalid-type-arguments] Too many type arguments: expected 1, got 2
+aliases_implicit.py:79:29: error[invalid-type-arguments] Too many type arguments: expected 1, got 2
+aliases_implicit.py:80:29: error[invalid-type-arguments] Too many type arguments: expected 1, got 2
+aliases_implicit.py:81:25: error[invalid-type-arguments] Type `str` is not assignable to upper bound `int | float` of type variable `TFloat@GoodTypeAlias12`
+aliases_implicit.py:135:20: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
```

New true positives ✔️ 

```diff
+callables_annotation.py:172:19: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
+callables_annotation.py:175:19: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
+callables_annotation.py:188:25: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
+callables_annotation.py:189:25: error[invalid-type-arguments] Too many type arguments: expected 0, got 1
```

These require `ParamSpec` and `Concatenate`.

```diff
-generics_defaults_specialization.py:26:5: error[type-assertion-failure] Type `SomethingWithNoDefaults[int, str]` does not match asserted type `SomethingWithNoDefaults[int, typing.TypeVar]`
+generics_defaults_specialization.py:26:5: error[type-assertion-failure] Type `SomethingWithNoDefaults[int, str]` does not match asserted type `SomethingWithNoDefaults[int, DefaultStrT]`
```

Favorable diagnostic change ✔️ 

```diff
-generics_defaults_specialization.py:27:5: error[type-assertion-failure] Type `SomethingWithNoDefaults[int, bool]` does not match asserted type `@Todo(specialized generic alias in type expression)`
```

New true negative ✔️ 

```diff
-generics_defaults_specialization.py:30:1: error[non-subscriptable] Cannot subscript object of type `<class 'SomethingWithNoDefaults[int, typing.TypeVar]'>` with no `__class_getitem__` method
+generics_defaults_specialization.py:30:15: error[invalid-type-arguments] Too many type arguments: expected between 0 and 1, got 2
```

Correct new diagnostic ✔️ 


```diff
-generics_variance.py:175:25: error[non-subscriptable] Cannot subscript object of type `<class 'Contra[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:175:35: error[non-subscriptable] Cannot subscript object of type `<class 'Co[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:179:29: error[non-subscriptable] Cannot subscript object of type `<class 'Contra[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:179:39: error[non-subscriptable] Cannot subscript object of type `<class 'Contra[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:183:21: error[non-subscriptable] Cannot subscript object of type `<class 'Co[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:183:27: error[non-subscriptable] Cannot subscript object of type `<class 'Co[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:187:25: error[non-subscriptable] Cannot subscript object of type `<class 'Co[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:187:31: error[non-subscriptable] Cannot subscript object of type `<class 'Contra[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:191:33: error[non-subscriptable] Cannot subscript object of type `<class 'Contra[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:191:43: error[non-subscriptable] Cannot subscript object of type `<class 'Co[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:191:49: error[non-subscriptable] Cannot subscript object of type `<class 'Contra[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:196:5: error[non-subscriptable] Cannot subscript object of type `<class 'Contra[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:196:15: error[non-subscriptable] Cannot subscript object of type `<class 'Contra[typing.TypeVar]'>` with no `__class_getitem__` method
-generics_variance.py:196:25: error[non-subscriptable] Cannot subscript object of type `<class 'Contra[typing.TypeVar]'>` with no `__class_getitem__` method
```

One of these should apparently be an error, but not of this kind, so
this is good ✔️

```diff
-specialtypes_type.py:152:16: error[invalid-type-form] `typing.TypeVar` is not a generic class
-specialtypes_type.py:156:16: error[invalid-type-form] `typing.TypeVar` is not a generic class
```

Good, those were false positives. ✔️ 

I skipped the analysis for everything involving `TypeVarTuple`.

## Ecosystem impact

**[Full report with detailed
diff](https://david-generic-implicit-alias.ecosystem-663.pages.dev/diff)**

Previous iterations of this PR showed all kinds of problems. In it's
current state, I do not see any large systematic problems, but it is
hard to tell with 5k diagnostic changes.

## Performance

* There is a huge 4x regression in `colour-science/colour`, related to
[this large
file](https://github.com/colour-science/colour/blob/develop/colour/io/luts/tests/test_lut.py)
with [many assignments of hard-coded arrays (lists of lists) to
`np.NDArray`
types](83e754c8b6/colour/io/luts/tests/test_lut.py (L701-L781))
that we now understand. We now take ~2 seconds to check this file, so
definitely not great, but maybe acceptable for now.

## Test Plan

Updated and new Markdown tests
2025-11-28 20:38:24 +01:00
Aria Desires c534bfaf01
[ty] Implement patterns and typevars in the LSP (#21671)
## Summary

**This is the final goto-targets with missing
goto-definition/declaration implementations!
You can now theoretically click on all the user-defined names in all the
syntax. 🎉**

This adds:

* goto definition/declaration on patterns/typevars
* find-references/rename on patterns/typevars
* fixes syntax highlighting of `*rest` patterns

This notably *does not* add:

* goto-type for patterns/typevars 
* hover for patterns/typevars (because that's just goto-type for names)

Also I realized we were at the precipice of one of the great GotoTarget
sins being resolved, and so I made import aliases also resolve to a
ResolvedDefinition. This removes a ton of cruft and prevents further
backsliding.

Note however that import aliases are, in general, completely jacked up
when it comes to find-references/renames (both before and after this
PR). Previously you could try to rename an import alias and it just
wouldn't do anything. With this change we instead refuse to even let you
try to rename it.

Sorting out why import aliases are jacked up is an ongoing thing I hope
to handle in a followup.

## Test Plan

You'll surely not regret checking in 86 snapshot tests
2025-11-28 13:41:21 +00:00
Aria Desires 209ea06592
Implement goto-definition and find-references for global/nonlocal statements (#21616)
## Summary

The implementation here is to just record the idents of these statements
in `scopes_by_expression` (which already supported idents but only ones
that happened to appear in expressions), so that `definitions_for_name`
Just Works.

goto-type (and therefore hover) notably does not work on these
statements because the typechecker does not record info for them. I am
tempted to just introduce `type_for_name` which runs
`definitions_for_name` to find other expressions and queries the
inferred type... but that's a bit whack because it won't be the computed
type at the right point in the code. It probably wouldn't be
particularly expensive to just compute/record the type at those nodes,
as if they were a load, because global/nonlocal is so scarce?

## Test Plan

Snapshot tests added/re-enabled.
2025-11-25 08:56:57 -05:00
Douglas Creager 03fe560164
[ty] Substitute for `typing.Self` when checking protocol members (#21569)
This patch updates our protocol assignability checks to substitute for
any occurrences of `typing.Self` in method signatures, replacing it with
the class being checked for assignability against the protocol.

This requires a new helper method on signatures, `apply_self`, which
substitutes occurrences of `typing.Self` _without_ binding the `self`
parameter.

We also update the `try_upcast_to_callable` method. Before, it would
return a `Type`, since certain types upcast to a _union_ of callables,
not to a single callable. However, even in that case, we know that every
element of the union is a callable. We now return a vector of
`CallableType`. (Actually a smallvec to handle the most common case of a
single callable; and wrapped in a new type so that we can provide helper
methods.) If there is more than one element in the result, it represents
a union of callables. This lets callers get at the `CallableType`
instances in a more type-safe way. (This makes it easier for our
protocol checking code to call the new `apply_self` helper.) We also
provide an `into_type` method so that callers that really do want a
`Type` can get the original result easily.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-11-24 14:05:09 -05:00
Alex Waygood e642874cf1
[ty] Check method definitions on subclasses for Liskov violations (#21436) 2025-11-23 18:08:15 +00:00
Alex Waygood 3410041b4c
[ty] Improve diagnostics when a submodule is not available as an attribute on a module-literal type (#21561) 2025-11-22 14:07:48 +00:00
Aria Desires 768bb24cdf
[ty] make implicit submodule imports re-exported (#21573)
Thus they work in `.pyi` files

Closes https://github.com/astral-sh/ty/issues/1609

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-11-21 17:42:11 -08:00
David Peter 29acc1e860
[ty] Support class-arguments for dataclass transformers (#21457)
## Summary

Allow metaclass-based and baseclass-based dataclass-transformers to
overwrite the default behavior using class arguments:

```py
class Person(Model, order=True):
    # ...
```

## Conformance tests

Four new tests passing!

## Test Plan

New Markdown tests
2025-11-15 17:47:48 +01:00
Bhuminjay Soni 8529d79a70
[ty] name is parameter and global is a syntax error (#21312)
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
2025-11-14 18:15:34 +00:00
Alex Waygood 5f501374c4
[ty] Support attribute-expression `TYPE_CHECKING` conditionals (#21449) 2025-11-14 13:11:49 +00:00
Micha Reiser 67e54fffe1
[ty] Fix panic for cyclic star imports (#21428) 2025-11-13 15:38:09 +01:00
Shunsuke Shibayama 9dd666d677
[ty] fix global symbol lookup from eager scopes (#21317)
## Summary

cf. https://github.com/astral-sh/ruff/pull/20962

In the following code, `foo` in the comprehension was not reported as
unresolved:

```python
# error: [unresolved-reference] "Name `foo` used when not defined"
foo
foo = [
    # no error!
    # revealed: Divergent
    reveal_type(x) for _ in () for x in [foo]
]

baz = [
    # error: [unresolved-reference] "Name `baz` used when not defined"
    # revealed: Unknown
    reveal_type(x) for _ in () for x in [baz]
]
```

In fact, this is a more serious bug than it looks: for `foo`,
[`explicit_global_symbol` is
called](6cc3393ccd/crates/ty_python_semantic/src/types/infer/builder.rs (L8052)),
causing a symbol that should actually be `Undefined` to be reported as
being of type `Divergent`.

This PR fixes this bug. As a result, the code in
`mdtest/regression/pr_20962_comprehension_panics.md` no longer panics.

## Test Plan

`corpus\cyclic_symbol_in_comprehension.py` is added.
New tests are added in `mdtest/comprehensions/basic.md`.

---------

Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Carl Meyer <carl@astral.sh>
2025-11-12 10:15:51 -08:00
Micha Reiser 43427abb61
[ty] Improve semantic token classification for names (#21399) 2025-11-12 16:34:26 +00:00
Shaygan Hooshyari 988c38c013
[ty] Skip eagerly evaluated scopes for attribute storing (#20856)
## Summary

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

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

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

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

The fix works by adjusting the following logics:

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

```py
class D:
    g: int

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

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

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


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

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

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

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

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-11-11 14:45:34 -08:00
Aria Desires e4374f14ed
[ty] Consider `from thispackage import y` to re-export `y` in `__init__.pyi` (#21387)
Fixes https://github.com/astral-sh/ty/issues/1487

This one is a true extension of non-standard semantics, and is therefore
a certified Hot Take we might conclude is simply a Bad Take (let's see
what ecosystem tests say...).
2025-11-11 14:41:14 -05:00
Aria Desires bd8812127d
[ty] support absolute `from` imports introducing local submodules in `__init__.py` files (#21372)
By resolving `.` and the LHS of the from import during semantic
indexing, we can check if the LHS is a submodule of `.`, and handle
`from whatever.thispackage.x.y import z` exactly like we do `from .x.y
import z`.

Fixes https://github.com/astral-sh/ty/issues/1484
2025-11-11 13:04:42 -05:00
Aria Desires 9ce3230add
[ty] Make implicit submodule imports only occur in global scope (#21370)
This loses any ability to have "per-function" implicit submodule
imports, to avoid the "ok but now we need per-scope imports" and "ok but
this should actually introduce a global that only exists during this
function" problems. A simple and clean implementation with no weird
corners.

Fixes https://github.com/astral-sh/ty/issues/1482
2025-11-10 18:59:48 -05:00
Aria Desires 2bc6c78e26
[ty] introduce local variables for `from` imports of submodules in `__init__.py(i)` (#21173)
This rips out the previous implementation in favour of a new
implementation with 3 rules:

- **froms are locals**: a `from..import` can only define locals, it does
not have global
side-effects. Specifically any submodule attribute `a` that's implicitly
introduced by either
`from .a import b` or `from . import a as b` (in an `__init__.py(i)`) is
a local and not a
global. If you do such an import at the top of a file you won't notice
this. However if you do
such an import in a function, that means it will only be function-scoped
(so you'll need to do
it in every function that wants to access it, making your code less
sensitive to execution
    order).

- **first from first serve**: only the *first* `from..import` in an
`__init__.py(i)` that imports a
particular direct submodule of the current package introduces that
submodule as a local.
Subsequent imports of the submodule will not introduce that local. This
reflects the fact that
in actual python only the first import of a submodule (in the entire
execution of the program)
introduces it as an attribute of the package. By "first" we mean "the
first time in this scope
(or any parent scope)". This pairs well with the fact that we are
specifically introducing a
local (as long as you don't accidentally shadow or overwrite the local).

- **dot re-exports**: `from . import a` in an `__init__.pyi` is
considered a re-export of `a`
(equivalent to `from . import a as a`). This is required to properly
handle many stubs in the
    wild. Currently it must be *exactly* `from . import ...`.
    
This implementation is intentionally limited/conservative (notably,
often requiring a from import to be relative). I'm going to file a ton
of followups for improvements so that their impact can be evaluated
separately.


Fixes https://github.com/astral-sh/ty/issues/133
2025-11-10 23:04:56 +00:00
Bhuminjay Soni cddc0fedc2
[syntax-error]: no binding for nonlocal PLE0117 as a semantic syntax error (#21032)
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## Summary

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

This PR ports PLE0117 as a semantic syntax error.

## Test Plan

<!-- How was it tested? -->
Tests previously written

---------

Signed-off-by: 11happy <soni5happy@gmail.com>
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-11-05 19:13:28 +00:00
Alex Waygood 39f105bc4a
[ty] Use "cannot" consistently over "can not" (#21255) 2025-11-03 10:38:20 -05:00
Micha Reiser 921f409ee8
Update Rust toolchain to 1.91 (#21179) 2025-11-01 01:50:58 +00:00
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

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

## Test Plan

<!-- How was it tested? -->
2025-10-31 14:29:24 +00:00
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
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
Shunsuke Shibayama 83a00c0ac8
[ty] follow the breaking API changes made in salsa-rs/salsa#1015 (#21117) 2025-10-29 14:56:12 +00:00
Micha Reiser 76a55314e4
Fix rare multithreaded related hang (#21038) 2025-10-23 09:25:16 +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
Bhuminjay Soni 3dd78e711e
[syntax-errors] Name is parameter and global (#20426)
## Summary

<!-- What's the purpose of the change? What does it do, and why? -->
This PR implements a new semantic syntax error where name is parameter &
global.

## Test Plan

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

---------

Signed-off-by: 11happy <soni5happy@gmail.com>
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
2025-10-21 16:51:16 +00:00
Shunsuke Shibayama a7c38eb122
[ty] display variance on hover over type variables (#20900) 2025-10-20 17:28:36 +00:00
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
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
Shunsuke Shibayama 9de34e7ac1
[ty] refactor `Place` (#20871)
## Summary

Part of astral-sh/ty#1341

The following changes will be made to `Place`.

* Introduce `TypeOrigin`
* `Place::Type` -> `Place::Defined`
* `Place::Unbound` -> `Place::Undefined`
* `Boundness` -> `Definedness`

`TypeOrigin::Declared`+`Definedness::PossiblyUndefined` are patterns
that weren't considered before, but this PR doesn't address them yet,
only refactors.

## Test Plan

Refactoring
2025-10-15 20:19:19 +02:00
David Peter f73bb45be6
[ty] Rename Type unwrapping methods (#20857)
## Summary

Rename "unwrapping" methods on `Type` from e.g.
`Type::into_class_literal` to `Type::as_class_literal`. I personally
find that name more intuitive, since no transformation of any kind is
happening. We are just unwrapping from certain enum variants. An
alternative would be `try_as_class_literal`, which would follow the
[`strum` naming
scheme](https://docs.rs/strum/latest/strum/derive.EnumTryAs.html), but
is slightly longer.

Also rename `Type::into_callable` to `Type::try_upcast_to_callable`.
Note that I intentionally kept names like
`FunctionType::into_callable_type`, because those return `CallableType`,
not `Option<Type<…>>`.

## Test Plan

Pure refactoring
2025-10-14 09:53:29 +02:00
Bhuminjay Soni 2b729b4d52
[syntax-errors]: break outside loop F701 (#20556)
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## Summary

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This PR implements https://docs.astral.sh/ruff/rules/break-outside-loop/
(F701) as a semantic syntax error.

## Test Plan

<!-- How was it tested? -->

---------

Signed-off-by: 11happy <soni5happy@gmail.com>
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
2025-10-13 20:00:59 +00:00
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
Takayuki Maeda 666f53331f
[`ruff`] Fix minor typos in doc comments (#20623) 2025-09-29 08:56:23 +02:00
Micha Reiser 3ffe56d19d
[ty] Remove unnecessary `FileScopeId` to `ScopeId` conversion (#20481) 2025-09-20 11:20:10 +00:00
Andrew Gallant cf16fc4aa4 [ty] Export some stuff from `ty_python_semantic`
We're going to want to use this outside of `ty_python_semantic`.
Specifically, in `ty_ide`.
2025-09-17 13:59:28 -04:00
Ibraheem Ahmed 36888198a6
[ty] Integrate type context for bidirectional inference (#20337)
## Summary

Adds the infrastructure necessary to perform bidirectional type
inference (https://github.com/astral-sh/ty/issues/168) without any
typing changes.
2025-09-11 15:19:12 -04:00
Douglas Creager abb705aa4e
[ty] Add dedicated variant for `NominalInstance(object)` (#20340)
Previously, `Type::object` would find the definition of the `object`
class in typeshed, load that in (to produce a `ClassLiteral` and
`ClassType`), and then create a `NominalInstance` of that class.

It's possible that we are using a typeshed that doesn't define `object`.
We will not be able to do much useful work with that kind of typeshed,
but it's still a possibility that we have to support at least without
panicking. Previously, we would handle this situation by falling back on
`Unknown`.

In most cases, that's a perfectly fine fallback! But `object` is also
our top type — the type of all values. `Unknown` is _not_ an acceptable
stand-in for the top type.

This PR adds a new `NominalInstance` variant for "instances of
`object`". Unlike other nominal instances, we do not need to load in
`object`'s `ClassType` to instantiate this variant. We will use this new
variant even when the current typeshed does not define an `object`
class, ensuring that we have a fully static representation of our top
type at all times.

There are several operations that need access to a nominal instance's
class, and for this new `object` variant we load it lazily only when
it's needed. That means this operation is now fallible, since this is
where the "typeshed doesn't define `object`" failure shows up.

This new approach also has the benefit of avoiding some salsa cycles
that were cropping up while I was debugging #20093, since the new
constraint set representation was trying to instantiate `Type::object`
while in the middle of processing its definition in typeshed. Cycle
handling was kicking in correctly and returning the `Unknown` fallback
mentioned above. But the constraint set implementation depends on
`Type::object` being a distinct and fully static type, highlighting that
this is a correctness fix, not just an optimization fix.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-09-11 13:02:58 -04:00
Shunsuke Shibayama 8770b95509
[ty] introduce `DivergentType` (#20312)
## Summary

From #17371

In #17371, `DivergentType` was introduced to prevent type inference for
recursive functions from diverging and causing panics. This turned out
to be useful for other divergent type inferences
(https://github.com/astral-sh/ruff/pull/17371#discussion_r2329337965),
so I extracted the introduction part of `DivergentType` into this PR so
that we can use it without waiting for the merge of #17371.

Note that this PR only introduces `DivergentType` and does not actually
address divergent type inference yet. Please refer to
https://github.com/astral-sh/ruff/pull/17371/files#diff-20b910c6e20faa962bb1642e111db1cbad8e66ace089bdd966ac9d7f9fa99ff2R542-R622
etc. when implementing handling of divergence suppression using this
type.

## Test Plan

---------

Co-authored-by: Carl Meyer <carl@oddbird.net>
2025-09-10 08:32:26 -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