This is a follow-on to #19410 that further reduces the memory usage of
our reachability constraints. When finishing the building of a use-def
map, we walk through all of the "final" states and mark only those
reachability constraints as "used". We then throw away the interior TDD
nodes of any reachability constraints that weren't marked as used.
(This helps because we build up quite a few intermediate TDD nodes when
constructing complex reachability constraints. These nodes can never be
accessed if they were _only_ used as an intermediate TDD node. The
marking step ensures that we keep any nodes that ended up being referred
to in some accessible use-def map state.)
## Summary
Adds proper type inference for implicit instance attributes that are
declared with a "bare" `Final` and adds `invalid-assignment` diagnostics
for all implicit instance attributes that are declared `Final` or
`Final[…]`.
## Test Plan
New and updated MD tests.
## Ecosystem analysis
```diff
pytest (https://github.com/pytest-dev/pytest)
+ error[invalid-return-type] src/_pytest/fixtures.py:1662:24: Return type does not match returned value: expected `Scope`, found `Scope | (Unknown & ~None & ~((...) -> object) & ~str) | (((str, Config, /) -> Unknown) & ~((...) -> object) & ~str) | (Unknown & ~str)
```
The definition of the `scope` attribute is [here](
5f99385635/src/_pytest/fixtures.py (L1020-L1028)).
Looks like this is a new false positive due to missing `TypeAlias`
support that is surfaced here because we now infer a more precise type
for `FixtureDef._scope`.
## Summary
Implement expansion of enums into unions of enum literals (and the
reverse operation). For the enum below, this allows us to understand
that `Color = Literal[Color.RED, Color.GREEN, Color.BLUE]`, or that
`Color & ~Literal[Color.RED] = Literal[Color.GREEN, Color.BLUE]`. This
helps in exhaustiveness checking, which is why we see some removed
`assert_never` false positives. And since exhaustiveness checking also
helps with understanding terminal control flow, we also see a few
removed `invalid-return-type` and `possibly-unresolved-reference` false
positives. This PR also adds expansion of enums in overload resolution
and type narrowing constructs.
```py
from enum import Enum
from typing_extensions import Literal, assert_never
from ty_extensions import Intersection, Not, static_assert, is_equivalent_to
class Color(Enum):
RED = 1
GREEN = 2
BLUE = 3
type Red = Literal[Color.RED]
type Green = Literal[Color.GREEN]
type Blue = Literal[Color.BLUE]
static_assert(is_equivalent_to(Red | Green | Blue, Color))
static_assert(is_equivalent_to(Intersection[Color, Not[Red]], Green | Blue))
def color_name(color: Color) -> str: # no error here (we detect that this can not implicitly return None)
if color is Color.RED:
return "Red"
elif color is Color.GREEN:
return "Green"
elif color is Color.BLUE:
return "Blue"
else:
assert_never(color) # no error here
```
## Performance
I avoided an initial regression here for large enums, but the
`UnionBuilder` and `IntersectionBuilder` parts can certainly still be
optimized. We might want to use the same technique that we also use for
unions of other literals. I didn't see any problems in our benchmarks so
far, so this is not included yet.
## Test Plan
Many new Markdown tests
## Summary
Emit errors for the following assignments:
```py
class C:
CLASS_LEVEL_CONSTANT: Final[int] = 1
C.CLASS_LEVEL_CONSTANT = 2
C().CLASS_LEVEL_CONSTANT = 2
```
## Test Plan
Updated and new MD tests
This PR extends the "go to declaration" and "go to definition"
functionality to support import statements — both standard imports and
"from" import forms.
---------
Co-authored-by: UnboundVariable <unbound@gmail.com>
* [x] basic handling
* [x] parse and discover `@warnings.deprecated` attributes
* [x] associate them with function definitions
* [x] associate them with class definitions
* [x] add a new "deprecated" diagnostic
* [x] ensure diagnostic is styled appropriately for LSPs
(DiagnosticTag::Deprecated)
* [x] functions
* [x] fire on calls
* [x] fire on arbitrary references
* [x] classes
* [x] fire on initializers
* [x] fire on arbitrary references
* [x] methods
* [x] fire on calls
* [x] fire on arbitrary references
* [ ] overloads
* [ ] fire on calls
* [ ] fire on arbitrary references(??? maybe not ???)
* [ ] only fire if the actual selected overload is deprecated
* [ ] dunder desugarring (warn on deprecated `__add__` if `+` is
invoked)
* [ ] alias supression? (don't warn on uses of variables that deprecated
items were assigned to)
* [ ] import logic
* [x] fire on imports of deprecated items
* [ ] suppress subsequent diagnostics if the import diagnostic fired (is
this handled by alias supression?)
* [x] fire on all qualified references (`module.mydeprecated`)
* [x] fire on all references that depend on a `*` import
Fixes https://github.com/astral-sh/ty/issues/153
Fixes https://github.com/astral-sh/ty/issues/769.
**Updated:** The preferred approach here is to keep the SemanticIndex
simple (`del` of any name marks that name "bound" in the current scope)
and to move complexity to type inference (free variable resolution stops
when it finds a binding, unless that binding is declared `nonlocal`). As
part of this change, free variable resolution will now union the types
it finds as it walks in enclosing scopes. This approach is still
incomplete, because it doesn't consider inner scopes or sibling scopes,
but it improves the common case.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
This PR builds upon #19371. It addresses a few additional code review
suggestions and adds support for attribute accesses (expressions of the
form `x.y`) and keyword arguments within call expressions.
---------
Co-authored-by: UnboundVariable <unbound@gmail.com>
This change makes it so we aren't doing a directory traversal every time
we ask for completions from a module. Specifically, submodules that
aren't attributes of their parent module can only be discovered by
looking at the directory tree. But we want to avoid doing a directory
scan unless we think there are changes.
To make this work, this change does a little bit of surgery to
`FileRoot`. Previously, a `FileRoot` was only used for library search
paths. Its revision was bumped whenever a file in that tree was added,
deleted or even modified (to support the discovery of `pth` files and
changes to its contents). This generally seems fine since these are
presumably dependency paths that shouldn't change frequently.
In this change, we add a `FileRoot` for the project. But having the
`FileRoot`'s revision bumped for every change in the project makes
caching based on that `FileRoot` rather ineffective. That is, cache
invalidation will occur too aggressively. To the point that there is
little point in adding caching in the first place. To mitigate this, a
`FileRoot`'s revision is only bumped on a change to a child file's
contents when the `FileRoot` is a `LibrarySearchPath`. Otherwise, we
only bump the revision when a file is created or added.
The effect is that, at least in VS Code, when a new module is added or
removed, this change is picked up and the cache is properly invalidated.
Other LSP clients with worse support for file watching (which seems to
be the case for the CoC vim plugin that I use) don't work as well. Here,
the cache is less likely to be invalidated which might cause completions
to have stale results. Unless there's an obvious way to fix or improve
this, I propose punting on improvements here for now.
## Summary
This PR updates the server to keep track of open files both system and
virtual files.
This is done by updating the project by adding the file in the open file
set in `didOpen` notification and removing it in `didClose`
notification.
This does mean that for workspace diagnostics, ty will only check open
files because the behavior of different diagnostic builder is to first
check `is_file_open` and only add diagnostics for open files. So, this
required updating the `is_file_open` model to be `should_check_file`
model which validates whether the file needs to be checked based on the
`CheckMode`. If the check mode is open files only then it will check
whether the file is open. If it's all files then it'll return `true` by
default.
Closes: astral-sh/ty#619
## Test Plan
### Before
There are two files in the project: `__init__.py` and `diagnostics.py`.
In the video, I'm demonstrating the old behavior where making changes to
the (open) `diagnostics.py` file results in re-parsing the file:
https://github.com/user-attachments/assets/c2ac0ecd-9c77-42af-a924-c3744b146045
### After
Same setup as above.
In the video, I'm demonstrating the new behavior where making changes to
the (open) `diagnostics.py` file doesn't result in re-parting the file:
https://github.com/user-attachments/assets/7b82fe92-f330-44c7-b527-c841c4545f8f
This PR is changes how `reveal_type` determines what type to reveal, in
a way that should be a no-op to most callers.
Previously, we would reveal the type of the first parameter, _after_ all
of the call binding machinery had done its work. This includes inferring
the specialization of a generic function, and then applying that
specialization to all parameter and argument types, which is relevant
since the typeshed definition of `reveal_type` is generic:
```pyi
def reveal_type(obj: _T, /) -> _T: ...
```
Normally this does not matter, since we infer `_T = [arg type]` and
apply that to the parameter type, yielding `[arg type]`. But applying
that specialization also simplifies the argument type, which makes
`reveal_type` less useful as a debugging aid when we want to see the
actual, raw, unsimplified argument type.
With this patch, we now grab the original unmodified argument type and
reveal that instead.
In addition to making the debugging aid example work, this also makes
our `reveal_type` implementation more robust to custom typeshed
definitions, such as
```py
def reveal_type(obj: Any) -> Any: ...
```
(That custom definition is probably not what anyone would want, since
you wouldn't be able to depend on the return type being equivalent to
the argument type, but still)
This PR implements "go to definition" and "go to declaration"
functionality for name nodes only. Future PRs will add support for
attributes, module names in import statements, keyword argument names,
etc.
This PR:
* Registers a declaration and definition request handler for the
language server.
* Splits out the `goto_type_definition` into its own module. The `goto`
module contains functionality that is common to `goto_type_definition`,
`goto_declaration` and `goto_definition`.
* Roughs in a new module `stub_mapping` that is not yet implemented. It
will be responsible for mapping a definition in a stub file to its
corresponding definition(s) in an implementation (source) file.
* Adds a new IDE support function `definitions_for_name` that collects
all of the definitions associated with a name and resolves any imports
(recursively) to find the original definitions associated with that
name.
* Adds a new `VisibleAncestorsIter` stuct that iterates up the scope
hierarchy but skips scopes that are not visible to starting scope.
---------
Co-authored-by: UnboundVariable <unbound@gmail.com>
## Summary
Resolves https://github.com/astral-sh/ty/issues/339
Supports having a blank function body inside `if TYPE_CHECKING` block or
in the elif or else of a `if not TYPE_CHECKING` block.
```py
if TYPE_CHECKING:
def foo() -> int: ...
if not TYPE_CHECKING: ...
else:
def bar() -> int: ...
```
## Test Plan
Update `function/return_type.md`
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
This is a follow-up to https://github.com/astral-sh/ruff/pull/19344 that
improves the error formatting slightly. For example with this program:
```py
def f():
global foo, bar
```
Before we printed:
```
1 | def f():
2 | global foo, bar
| ^^^^^^^^^^^^^^^ `foo` has no declarations or bindings in the global scope
...
1 | def f():
2 | global foo, bar
| ^^^^^^^^^^^^^^^ `bar` has no declarations or bindings in the global scope
```
Now we print:
```
1 | def f():
2 | global foo, bar
| ^^^ `foo` has no declarations or bindings in the global scope
...
1 | def f():
2 | global foo, bar
| ^^^ `bar` has no declarations or bindings in the global scope
```
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Previously this worked if there was also a binding in the same scope as
the `global` declaration (probably almost always the case), but CPython
doesn't require this.
This change surfaced an error in an existing test, where a global
variable was only ever declared and bound using the `global` keyword,
and never mentioned explicitly in the global scope. @AlexWaygood
suggested we probably want to keep that requirement, so I'm adding an a
new test for that on top of fixing the failing test.
## Summary
Add a new `Type::EnumLiteral(…)` variant and infer this type for member
accesses on enums.
**Example**: No more `@Todo` types here:
```py
from enum import Enum
class Answer(Enum):
YES = 1
NO = 2
def is_yes(self) -> bool:
return self == Answer.YES
reveal_type(Answer.YES) # revealed: Literal[Answer.YES]
reveal_type(Answer.YES == Answer.NO) # revealed: Literal[False]
reveal_type(Answer.YES.is_yes()) # revealed: bool
```
## Test Plan
* Many new Markdown tests for the new type variant
* Added enum literal types to property tests, ran property tests
## Ecosystem analysis
Summary:
Lots of false positives removed. All of the new diagnostics are
either new true positives (the majority) or known problems. Click for
detailed analysis</summary>
Details:
```diff
AutoSplit (https://github.com/Toufool/AutoSplit)
+ error[call-non-callable] src/capture_method/__init__.py:137:9: Method `__getitem__` of type `bound method CaptureMethodDict.__getitem__(key: Never, /) -> type[CaptureMethodBase]` is not callable on object of type `CaptureMethodDict`
+ error[call-non-callable] src/capture_method/__init__.py:147:9: Method `__getitem__` of type `bound method CaptureMethodDict.__getitem__(key: Never, /) -> type[CaptureMethodBase]` is not callable on object of type `CaptureMethodDict`
+ error[call-non-callable] src/capture_method/__init__.py:148:1: Method `__getitem__` of type `bound method CaptureMethodDict.__getitem__(key: Never, /) -> type[CaptureMethodBase]` is not callable on object of type `CaptureMethodDict`
```
New true positives. That `__getitem__` method is apparently annotated
with `Never` to prevent developers from using it.
```diff
dd-trace-py (https://github.com/DataDog/dd-trace-py)
+ error[invalid-assignment] ddtrace/vendor/psutil/_common.py:29:5: Object of type `None` is not assignable to `Literal[AddressFamily.AF_INET6]`
+ error[invalid-assignment] ddtrace/vendor/psutil/_common.py:33:5: Object of type `None` is not assignable to `Literal[AddressFamily.AF_UNIX]`
```
Arguably true positives:
e0a772c28b/ddtrace/vendor/psutil/_common.py (L29)
```diff
ignite (https://github.com/pytorch/ignite)
+ error[invalid-argument-type] tests/ignite/engine/test_custom_events.py:190:34: Argument to bound method `__call__` is incorrect: Expected `((...) -> Unknown) | None`, found `Literal["123"]`
+ error[invalid-argument-type] tests/ignite/engine/test_custom_events.py:220:37: Argument to function `default_event_filter` is incorrect: Expected `Engine`, found `None`
+ error[invalid-argument-type] tests/ignite/engine/test_custom_events.py:220:43: Argument to function `default_event_filter` is incorrect: Expected `int`, found `None`
+ error[call-non-callable] tests/ignite/engine/test_custom_events.py:561:9: Object of type `CustomEvents` is not callable
+ error[invalid-argument-type] tests/ignite/metrics/test_frequency.py:50:38: Argument to bound method `attach` is incorrect: Expected `Events`, found `CallableEventWithFilter`
```
All true positives. Some of them are inside `pytest.raises(TypeError,
…)` blocks 🙃
```diff
meson (https://github.com/mesonbuild/meson)
+ error[invalid-argument-type] unittests/internaltests.py:243:51: Argument to bound method `__init__` is incorrect: Expected `bool`, found `Literal[MachineChoice.HOST]`
+ error[invalid-argument-type] unittests/internaltests.py:271:51: Argument to bound method `__init__` is incorrect: Expected `bool`, found `Literal[MachineChoice.HOST]`
```
New true positives. Enum literals can not be assigned to `bool`, even if
their value types are `0` and `1`.
```diff
poetry (https://github.com/python-poetry/poetry)
+ error[invalid-assignment] src/poetry/console/exceptions.py:101:5: Object of type `Literal[""]` is not assignable to `InitVar[str]`
```
New false positive, missing support for `InitVar`.
```diff
prefect (https://github.com/PrefectHQ/prefect)
+ error[invalid-argument-type] src/integrations/prefect-dask/tests/test_task_runners.py:193:17: Argument is incorrect: Expected `StateType`, found `Literal[StateType.COMPLETED]`
```
This is confusing. There are two definitions
([one](74d8cd93ee/src/prefect/client/schemas/objects.py (L89-L100)),
[two](https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/schemas/states.py#L40))
of the `StateType` enum. Here, we're trying to assign one to the other.
I don't think that should be allowed, so this is a true positive (?).
```diff
python-htmlgen (https://github.com/srittau/python-htmlgen)
+ error[invalid-assignment] test_htmlgen/form.py:51:9: Object of type `str` is not assignable to attribute `autocomplete` of type `Autocomplete | None`
+ error[invalid-assignment] test_htmlgen/video.py:38:9: Object of type `str` is not assignable to attribute `preload` of type `Preload | None`
```
True positives. [The stubs are
wrong](01e3b911ac/htmlgen/form.pyi (L8-L10)).
These should not contain type annotations, but rather just `OFF = ...`.
```diff
rotki (https://github.com/rotki/rotki)
+ error[invalid-argument-type] rotkehlchen/tests/unit/test_serialization.py:62:30: Argument to bound method `deserialize` is incorrect: Expected `str`, found `Literal[15]`
```
New true positive.
```diff
vision (https://github.com/pytorch/vision)
+ error[unresolved-attribute] test/test_extended_models.py:302:17: Type `type[WeightsEnum]` has no attribute `DEFAULT`
+ error[unresolved-attribute] test/test_extended_models.py:302:58: Type `type[WeightsEnum]` has no attribute `DEFAULT`
```
Also new true positives. No `DEFAULT` member exists on `WeightsEnum`.
The initial implementation of `infer_nonlocal` landed in
https://github.com/astral-sh/ruff/pull/19112 fails to report an error
for this example:
```py
x = 1
def f():
# This is only a usage of `x`, not a definition. It shouldn't be
# enough to make the `nonlocal` statement below allowed.
print(x)
def g():
nonlocal x
```
Fix this by continuing to walk enclosing scopes when the place we've
found isn't bound, declared, or `nonlocal`.
We previously had separate `CallArguments` and `CallArgumentTypes` types
in support of our two-phase call binding logic. `CallArguments` would
store only the arity/kind of each argument (positional, keyword,
variadic, etc). We then performed parameter matching using only this
arity/kind information, and then infered the type of each argument,
placing the result of this second phase into a new `CallArgumentTypes`.
In #18996, we will need to infer the types of splatted arguments
_before_ performing parameter matching, since we need to know the
argument type to accurately infer its length, which informs how many
parameters the splatted argument is matched against.
That makes this separation of Rust types no longer useful. This PR
merges everything back into a single `CallArguments`. In the case where
we are performing two-phase call binding, the types will be initialized
to `None`, and updated to the actual argument type during the second
`check_types` phase.
_[This is a refactoring in support of fixing the merge conflicts on
#18996. I've pulled this out into a separate PR to make it easier to
review in isolation.]_
Basically, we weren't quite using `Type::member` in every case
correctly. Specifically, this example from @sharkdp:
```
class Meta(type):
@property
def meta_attr(self) -> int:
return 0
class C(metaclass=Meta): ...
C.<CURSOR>
```
While we would return `C.meta_attr` here, we were claiming its type was
`property`. But its type should be `int`.
Ref https://github.com/astral-sh/ruff/pull/19216#discussion_r2197065241
## Summary
Adds a way to list all members of an `Enum` and implements almost all of
the mechanisms by which members are distinguished from non-members
([spec](https://typing.python.org/en/latest/spec/enums.html#defining-members)).
This has no effect on actual enums, so far.
## Test Plan
New Markdown tests using `ty_extensions.enum_members`.
While we did previously support submodule completions via our
`all_members` API, that only works when submodules are attributes of
their parent module. For example, `os.path`. But that didn't work when
the submodule was not an attribute of its parent. For example,
`http.client`. To make the latter work, we read the directory of the
parent module to discover its submodules.
This PR includes:
* Implemented core signature help logic
* Added new docstring method on Definition that returns a docstring for
function and class definitions
* Modified the display code for Signature that allows a signature string
to be broken into text ranges that correspond to each parameter in the
signature
* Augmented Signature struct so it can track the Definition for a
signature when available; this allows us to find the docstring
associated with the signature
* Added utility functions for parsing parameter documentation from three
popular docstring formats (Google, NumPy and reST)
* Implemented tests for all of the above
"Signature help" is displayed by an editor when you are typing a
function call expression. It is typically triggered when you type an
open parenthesis. The language server provides information about the
target function's signature (or multiple signatures), documentation, and
parameters.
Here is how this appears:
---------
Co-authored-by: UnboundVariable <unbound@gmail.com>
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
We noticed that all files get reparsed when workspace diagnostics are
enabled.
I realised that this is because `check_file_impl` access the parsed
module but itself isn't a salsa query.
This pr makes `check_file_impl` a salsa query, so that we only access
the `parsed_module` when the file actually changed. I decided to remove
the salsa query from `check_types` because most functions it calls are
salsa queries itself and having both `check_types` and `check_file` as
salsa querise has the downside that we double cache the diagnostics.
## Test Plan
**Before**
```
2025-07-10 12:54:16.620766000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c0c))}: File `/Users/micha/astral/test/yaml/yaml-stubs/__init__.pyi` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.621942000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c13))}: File `/Users/micha/astral/test/ignore2 2/nested-repository/main.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.622107000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c09))}: File `/Users/micha/astral/test/notebook.ipynb` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.622357000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c04))}: File `/Users/micha/astral/test/no-trailing.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.622634000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c02))}: File `/Users/micha/astral/test/simple.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.623056000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c07))}: File `/Users/micha/astral/test/open/more.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.623254000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c11))}: File `/Users/micha/astral/test/ignore-bug/backend/src/subdir/log/some_logging_lib.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.623450000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c0f))}: File `/Users/micha/astral/test/yaml/tomllib/__init__.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.624599000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c05))}: File `/Users/micha/astral/test/create.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.624784000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c00))}: File `/Users/micha/astral/test/lib.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.624911000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c0a))}: File `/Users/micha/astral/test/sub/test.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.625032000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c12))}: File `/Users/micha/astral/test/ignore2/nested-repository/main.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.625101000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c08))}: File `/Users/micha/astral/test/open/test.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.625227000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c03))}: File `/Users/micha/astral/test/pseudocode_with_bom.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.625353000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c0b))}: File `/Users/micha/astral/test/yaml/yaml-stubs/loader.pyi` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.625543000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c01))}: File `/Users/micha/astral/test/test_trailing.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.625616000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c0d))}: File `/Users/micha/astral/test/yaml/tomllib/_re.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.625667000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c06))}: File `/Users/micha/astral/test/yaml/main.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.625779000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c10))}: File `/Users/micha/astral/test/yaml/tomllib/_types.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.627526000 WARN request{id=19 method="workspace/diagnostic"}:Project::check:check_file{file=file(Id(c0e))}: File `/Users/micha/astral/test/yaml/tomllib/_parser.py` was reparsed after being collected in the current Salsa revision
2025-07-10 12:54:16.627959000 DEBUG request{id=19 method="workspace/diagnostic"}:Project::check: Checking all files took 0.007s
```
Now, no more logs regarding reparsing
This makes use of the new `Type` field on `Completion` to figure out the
"kind" of a `Completion`.
The mapping here is perhaps a little suspect for some cases.
Closesastral-sh/ty#775
Since we generally need (so far) to get the type information of each
suggestion to figure out its boundness anyway, we might as well expose
it here. Completions want to use this information to enhance the
metadata on each suggestion for a more pleasant user experience.
For the most part, this was pretty straight-forward. The most exciting
part was in computing the types for instance attributes. I'm not 100%
sure it's correct or is the best way to do it.
This commit doesn't change any behavior, but makes it so `all_members`
returns a `Vec<Member>` instead of `Vec<Name>`, where a `Member`
contains a `Name`. This gives us an expansion point to include other
data (such as the type of the `Name`).
## Summary
Change `ClassLiteral.into_callable` to also look for `__init__` functions
of type `Type::Callable` (such as synthesized `__init__` functions of
dataclasses).
Fixes https://github.com/astral-sh/ty/issues/760
## Test Plan
Add subtype test
---------
Co-authored-by: David Peter <mail@david-peter.de>
## Summary
Emit a diagnostic when a `Final`-qualified symbol is modified. This
first iteration only works for name targets. Tests with TODO comments
were added for attribute assignments as well.
related ticket: https://github.com/astral-sh/ty/issues/158
## Ecosystem impact
Correctly identified [modification of a `Final`
symbol](7b4164a5f2/sphinx/__init__.py (L44))
(behind a `# type: ignore`):
```diff
- warning[unused-ignore-comment] sphinx/__init__.py:44:56: Unused blanket `type: ignore` directive
```
And the same
[here](5471a37e82/src/trio/_core/_run.py (L128)):
```diff
- warning[unused-ignore-comment] src/trio/_core/_run.py:128:45: Unused blanket `type: ignore` directive
```
## Test Plan
New Markdown tests
## Summary
Fixes a bug where conditionally defined dataclass fields were previously
ignored.
Thanks to @lipefree for reporting this.
## Test Plan
New Markdown tests
## Summary
This PR addresses some additional feedback on #19053:
- Renaming the `syntax_error` methods to `invalid_syntax` to match the
lint id
- Moving the standalone `diagnostic_from_violation` function to
`Violation::into_diagnostic`
- Removing the `Ord` and `PartialOrd` implementations from `Diagnostic`
in favor of `Diagnostic::start_ordering`
## Test Plan
Existing tests
## Additional Follow-ups
Besides these, I also put the following comments on my todo list, but
they seemed like they might be big enough to have their own PRs:
- [Use `LintId::IOError` for IO
errors](https://github.com/astral-sh/ruff/pull/19053#discussion_r2189425922)
- [Move `Fix` and
`Edit`](https://github.com/astral-sh/ruff/pull/19053#discussion_r2189448647)
- [Avoid so many
unwraps](https://github.com/astral-sh/ruff/pull/19053#discussion_r2189465980)
## Summary
Related:
- https://github.com/astral-sh/ty/issues/111
- https://github.com/astral-sh/ruff/pull/17974#discussion_r2108527106
Previously, when validating an attribute assignment, a `__setattr__`
call check was only done if the attribute wasn't found as either a class
member or instance member
This PR changes the `__setattr__` call check to be attempted first,
prior to the "[normal
mechanism](https://docs.python.org/3/reference/datamodel.html#object.__setattr__)",
as a defined `__setattr__` should take precedence over setting an
attribute on the instance dictionary directly.
if the return type of `__setattr__` is `Never`, an `invalid-assignment`
diagnostic is emitted
Once this is merged, a subsequent PR will synthesize a `__setattr__`
method with a `Never` return type for frozen dataclasses.
## Test Plan
Existing tests + mypy_primer
---------
Co-authored-by: David Peter <mail@david-peter.de>
This PR implements a basic semantic token provider for ty's language
server. This allows for more accurate semantic highlighting / coloring
within editors that support this LSP functionality.
Here are screen shots that show how code appears in VS Code using the
"rainbow" theme both before and after this change.
The token types and modifier tags in this implementation largely mirror
those used in Microsoft's default language server for Python.
The implementation supports two LSP interfaces. The first provides
semantic tokens for an entire document, and the second returns semantic
tokens for a requested range within a document.
The PR includes unit tests. It also includes comments that document
known limitations and areas for future improvements.
---------
Co-authored-by: UnboundVariable <unbound@gmail.com>
## Summary
It was recently clarified in the [typing
spec](https://typing.python.org/en/latest/spec/class-compat.html#classvar)
that bare `ClassVar` annotations are allowed. For annotated assignments
with a right hand side value, the spec requires type checkers to infer
the type as something "to which [the] value is assignable". For a value
of `2`, the spec suggests `int`, `Literal[2]`, or `Any` as examples.
Here, we choose `Unknown | Literal[2]` instead, conforming with out
usual treatment of attribute types.
closes https://github.com/astral-sh/ty/issues/211
## Summary
This PR implements the following pieces of `Protocol` semantics:
1. A protocol with a method member that does not have a fully static
signature should not be considered fully static. I.e., this protocol is
not fully static because `Foo.x` has no return type; we previously
incorrectly considered that it was:
```py
class Foo(Protocol):
def f(self): ...
```
2. Two protocols `P1` and `P2`, both with method members `x`, should be
considered equivalent if the signature of `P1.x` is equivalent to the
signature of `P2.x`. Currently we do not recognize this.
Implementing these semantics requires distinguishing between method
members and non-method members. The stored type of a method member must
be eagerly upcast to a `Callable` type when collecting the protocol's
interface: doing otherwise would mean that it would be hard to implement
equivalence of protocols even in the face of differently ordered unions,
since the two equivalent protocols would have different Salsa IDs even
when normalized.
The semantics implemented by this PR are that we consider something a
method member if:
1. It is accessible on the class itself; and
2. It is a function-like callable: a callable type that also has a
`__get__` method, meaning it can be used as a method when accessed on
instances.
Note that the spec has complicated things to say about classmethod
members and staticmethod members. These semantics are not implemented by
this PR; they are all deferred for now.
The infrastructure added in this PR fixes bugs in its own right, but
also lays the groundwork for implementing subtyping and assignability
rules for method members of protocols. A (currently failing) test is
added to verify this.
## Test Plan
mdtests
## Summary
Infer the type of symbols with a `Final` qualifier as their
right-hand-side inferred type:
```py
x: Final = 1
y: Final[int] = 1
def _():
reveal_type(x) # previously: Unknown, now: Literal[1]
reveal_type(y) # int, same as before
```
Part of https://github.com/astral-sh/ty/issues/158
## Ecosystem analysis
### aiohttp
```diff
aiohttp (https://github.com/aio-libs/aiohttp)
+ error[invalid-argument-type] aiohttp/compression_utils.py:131:54: Argument to bound method `__init__` is incorrect: Expected `ZLibBackendProtocol`, found `<module 'zlib'>`
```
This code [creates a
protocol](a83597fa88/aiohttp/compression_utils.py (L52-L77))
that looks like
```pyi
class ZLibBackendProtocol(Protocol):
Z_FULL_FLUSH: int
Z_SYNC_FLUSH: int
# more fields…
```
It then [tries to
assign](a83597fa88/aiohttp/compression_utils.py (L131))
the module literal `zlib` to that protocol. Howefer, in typeshed, these
`zlib` members are annotated like this:
```pyi
Z_FULL_FLUSH: Final = 3
Z_SYNC_FLUSH: Final = 2
```
With the proposed change here, we now infer these as `Literal[3]` /
`Literal[2]`. Since protocol members have to be assignable both ways
(invariance), we do not consider `zlib` assignable to this protocol
anymore.
That seems rather unfortunate. Not sure who is to blame here? That
`ZLibBackendProtocol` protocol should probably not annotate the members
with `int`, given that `typeshed` doesn't use an explicit annotation
here either? But what should they do instead? Annotate those fields with
`Any`?
Or is it another case where we should consider literal-widening?
FYI @AlexWaygood
### cloud-init
```diff
cloud-init (https://github.com/canonical/cloud-init)
+ error[invalid-argument-type] tests/unittests/sources/test_smartos.py:575:32: Argument to function `oct` is incorrect: Expected `SupportsIndex`, found `int | float`
+ error[invalid-argument-type] tests/unittests/sources/test_smartos.py:593:32: Argument to function `oct` is incorrect: Expected `SupportsIndex`, found `int | float`
+ error[invalid-argument-type] tests/unittests/sources/test_smartos.py:647:35: Argument to function `oct` is incorrect: Expected `SupportsIndex`, found `int | float`
```
New false positives on expressions like
`oct(os.stat(legacy_script_f)[stat.ST_MODE])`. We now correctly infer
`stat.ST_MODE` as `Literal[1]`, because in typeshed, it is annotated as
`ST_MODE: Final = 0`. `os.stat` returns a `stat_result` which is a tuple
subclass. Accessing it at index 0 should return an `int`, but we
currently return `int | float`, presumably due to missing support for
tuple subclasses (FYI @AlexWaygood):
```pyi
class stat_result(structseq[float], tuple[int, int, int, int, int, int, int, float, float, float]):
```
In terms of `typing.Final`, things are working as expected here.
### pywin-32
Many new false positives similar to:
```diff
pywin32 (https://github.com/mhammond/pywin32)
+ error[invalid-argument-type] Pythonwin/pywin/docking/DockingBar.py:288:55: Argument to function `LoadCursor` is incorrect: Expected `PyResourceId`, found `Literal[32645]`
```
The line in question calls `win32api.LoadCursor(0, win32con.IDC_ARROW)`.
The `win32con.IDC_ARROW` symbol is annotated as [`IDC_ARROW: Final =
32512` in
typeshed](2408c028f4/stubs/pywin32/win32/lib/win32con.pyi (L594)),
but
[`LoadCursor`](2408c028f4/stubs/pywin32/win32/win32api.pyi (L197))
expects a
[`PyResourceId`](2408c028f4/stubs/pywin32/_win32typing.pyi (L1252)),
which is an empty class. So.. this seems like a true positive to me,
unless that typeshed annotation of `IDC_ARROW` is meant to imply that
the type should be `Unknown`/`Any`?
### streamlit
```diff
streamlit (https://github.com/streamlit/streamlit)
+ error[invalid-argument-type] lib/streamlit/string_util.py:163:37: Argument to bound method `translate` is incorrect: Expected `bytes`, found `bytearray`
```
This looks like a true positive? The code calls `inp.translate(None,
TEXTCHARS)`. `inp` is `bytes`, and `TEXTCHARS` is:
```py
TEXTCHARS: Final = bytearray(
{7, 8, 9, 10, 12, 13, 27} | set(range(0x20, 0x100)) - {0x7F}
)
```
~~We now infer this as `bytearray`, but `bytes.translate` [expects
`bytes` for its `delete`
parameter](2408c028f4/stdlib/builtins.pyi (L710)).
This seems to work at runtime, so maybe the typeshed annotation is
wrong?~~ (Edit: this is now fixed in typeshed)
```pycon
>>> b"abc".translate(None, bytearray(b"b"))
b'ac'
```
## rotki
```diff
+ error[invalid-return-type] rotkehlchen/chain/ethereum/modules/yearn/decoder.py:412:13: Return type does not match returned value: expected `dict[Unknown, str]`, found `dict[Unknown, Literal["yearn-v1", "yearn-v2"]]`
```
The code in question looks like
```py
def addresses_to_counterparties(self) -> dict[ChecksumEvmAddress, str]:
return dict.fromkeys(self.vaults, CPT_BEEFY_FINANCE)
```
where `CPT_BEEFY_FINANCE: Final = 'beefy_finance'. We previously
inferred the value type of the returned `dict` as `Unknown`, and now we
infer it as `Literal["beefy_finance"]`, which does not match the
annotated return type because `dict` is invariant in the value type.
```diff
+ error[invalid-argument-type] rotkehlchen/tests/unit/decoders/test_curve.py:249:9: Argument is incorrect: Expected `int`, found `FVal`
```
There are true positives that were previously silenced through the
`Unknown`.
## Test Plan
New Markdown tests
## Summary
Following ty issue [#698](https://github.com/astral-sh/ty/issues/698)
this PR adds support for declarations.
closes#698
## Test Plan
Tested against mdtest (specifically attributes).
---------
Co-authored-by: David Peter <mail@david-peter.de>
## Summary
`ty` does not understand that calls to functions which have been
annotated as having a return type of `Never` / `NoReturn` are terminal.
This PR fixes that, by adding new reachability constraints when call
expressions are seen. If the call expression evaluates to `Never`, the
code following it will be considered to be unreachable. Note that, for
adding these constraints, we only consider call expressions at the
statement level, and that too only inside function scopes. This is
because otherwise, the number of such constraints becomes too high, and
evaluating them later on during type inference results in a major
performance degradation.
Fixes https://github.com/astral-sh/ty/issues/180
## Test Plan
New mdtests.
## Ecosystem changes
This PR removes the following false-positives:
- "Function can implicitly return `None`, which is not assignable to
...".
- "Name `foo` used when possibly not defind" - because the branch in
which it is not defined has a `NoReturn` call, or when `foo` was
imported in a `try`, and the except had a `NoReturn` call.
---------
Co-authored-by: David Peter <mail@david-peter.de>
## Summary
Was just playing around with this, there's definitely more to do with
this function, but it seems like maybe a better option than having so
many arms in has_relation_to for (_, Callable).
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
This PR is a collaboration with @AlexWaygood from our pairing session
last Friday.
The main goal here is removing `ruff_linter::message::OldDiagnostic` in
favor of
using `ruff_db::diagnostic::Diagnostic` directly. This involved a few
major steps:
- Transferring the fields
- Transferring the methods and trait implementations, where possible
- Converting some constructor methods to free functions
- Moving the `SecondaryCode` struct
- Updating the method names
I'm hoping that some of the methods, especially those in the
`expect_ruff_*`
family, won't be necessary long-term, but I avoided trying to replace
them
entirely for now to keep the already-large diff a bit smaller.
### Related refactors
Alex and I noticed a few refactoring opportunities while looking at the
code,
specifically the very similar implementations for
`create_parse_diagnostic`,
`create_unsupported_syntax_diagnostic`, and
`create_semantic_syntax_diagnostic`.
We combined these into a single generic function, which I then copied
into
`ruff_linter::message` with some small changes and a TODO to combine
them in the
future.
I also deleted the `DisplayParseErrorType` and `TruncateAtNewline` types
for
reporting parse errors. These were added in #4124, I believe to work
around the
error messages from LALRPOP. Removing these didn't affect any tests, so
I think
they were unnecessary now that we fully control the error messages from
the
parser.
On a more minor note, I factored out some calls to the
`OldDiagnostic::filename`
(now `Diagnostic::expect_ruff_filename`) function to avoid repeatedly
allocating
`String`s in some places.
### Snapshot changes
The `show_statistics_syntax_errors` integration test changed because the
`OldDiagnostic::name` method used `syntax-error` instead of
`invalid-syntax`
like in ty. I think this (`--statistics`) is one of the only places we
actually
use this name for syntax errors, so I hope this is okay. An alternative
is to
use `syntax-error` in ty too.
The other snapshot changes are from removing this code, as discussed on
[Discord](https://discord.com/channels/1039017663004942429/1228460843033821285/1388252408848847069):
34052a1185/crates/ruff_linter/src/message/mod.rs (L128-L135)
I think both of these are technically breaking changes, but they only
affect
syntax errors and are very narrow in scope, while also pretty
substantially
simplifying the refactor, so I hope they're okay to include in a patch
release.
## Test plan
Existing tests, with the adjustments mentioned above
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
This implements filtering of private symbols from stub files based on
type information as discussed in
https://github.com/astral-sh/ruff/pull/19102. It extends the previous
implementation to apply to all stub files, instead of just the
`builtins` module, and uses type information to retain private names
that are may be relevant at runtime.
## Summary
Part of https://github.com/astral-sh/ty/issues/129
There were previously some false positives here.
## Test Plan
Updated `is_subtype_of.md` and `is_assignable_to.md`
## Summary
Allow declared-only class-level attributes to be accessed on the class:
```py
class C:
attr: int
C.attr # this is now allowed
```
closes https://github.com/astral-sh/ty/issues/384
closes https://github.com/astral-sh/ty/issues/553
## Ecosystem analysis
* We see many removed `unresolved-attribute` false-positives for code
that makes use of sqlalchemy, as expected (see changes for `prefect`)
* We see many removed `call-non-callable` false-positives for uses of
`pytest.skip` and similar, as expected
* Most new diagnostics seem to be related to cases like the following,
where we previously inferred `int` for `Derived().x`, but now we infer
`int | None`. I think this should be a
conflicting-declarations/bad-override error anyway? The new behavior may
even be preferred here?
```py
class Base:
x: int | None
class Derived(Base):
def __init__(self):
self.x: int = 1
```
## Summary
The motivation of `ScopedExpressionId` was that we have an expression
identifier that's local to a scope and, therefore, unlikely to change if
a user makes changes in another scope. A local identifier like this has
the advantage that query results may remain unchanged even if other
parts of the file change, which in turn allows Salsa to short-circuit
dependent queries.
However, I noticed that we aren't using `ScopedExpressionId` in a place
where it's important that the identifier is local. It's main use is
inside `infer` which we always run for the entire file. The one
exception to this is `Unpack` but unpack runs as part of `infer`.
Edit: The above isn't entirely correct. We used ScopedExpressionId in
TypeInference which is a query result. Now using ExpressionNodeKey does
mean that a change to the AST invalidates most if not all TypeInference
results of a single file. Salsa then has to run all dependent queries to
see if they're affected by this change even if the change was local to
another scope.
If this locality proves to be important I suggest that we create two
queries on top of TypeInference: one that returns the expression map
which is mainly used in the linter and type inference and a second that
returns all remaining fields. This should give us a similar optimization
at a much lower cost
I also considered remove `ScopedUseId` but I believe that one is still
useful because using `ExpressionNodeKey` for it instead would mean that
all `UseDefMap` change when a single AST node changes. Whether this is
important is something difficult to assess. I'm simply not familiar
enough with the `UseDefMap`. If the locality doesn't matter for the
`UseDefMap`, then a similar change could be made and `bindings_by_use`
could be changed to an `FxHashMap<UseId, Bindings>` where `UseId` is a
thin wrapper around `NodeKey`.
Closes https://github.com/astral-sh/ty/issues/721
## Summary
I hoped this might fix the latest stack overflows on
https://github.com/astral-sh/ruff/pull/18659... it doesn't look like it
does, but these changes seem like they're probably correct anyway...?
## Test Plan
<!-- How was it tested? -->
## Summary
Remove a hack in control flow modeling that was treating `return`
statements at the end of function bodies in a special way (basically
considering the state *just before* the `return` statement as the
end-of-scope state). This is not needed anymore now that #18750 has been
merged.
In order to make this work, we now use *all reachable bindings* for
purposes of finding implicit instance attribute assignments as well as
for deferred lookups of symbols. Both would otherwise be affected by
this change:
```py
def C:
def f(self):
self.x = 1 # a reachable binding that is not visible at the end of the scope
return
```
```py
def f():
class X: ... # a reachable binding that is not visible at the end of the scope
x: "X" = X() # deferred use of `X`
return
```
Implicit instance attributes also required another change. We previously
kept track of possibly-unbound instance attributes in some cases, but we
now give up on that completely and always consider *implicit* instance
attributes to be bound if we see a reachable binding in a reachable
method. The previous behavior was somewhat inconsistent anyway because
we also do not consider attributes possibly-unbound in other scenarios:
we do not (and can not) keep track of whether or not methods are called
that define these attributes.
closes https://github.com/astral-sh/ty/issues/711
## Ecosystem analysis
I think this looks very positive!
* We see an unsurprising drop in `possibly-unbound-attribute`
diagnostics (599), mostly for classes that define attributes in `try …
except` blocks, `for` loops, or `if … else: raise …` constructs. There
might obviously also be true positives that got removed, but the vast
majority should be false positives.
* There is also a drop in `possibly-unresolved-reference` /
`unresolved-reference` diagnostics (279+13) from the change to deferred
lookups.
* Some `invalid-type-form` false positives got resolved (13), because we
can now properly look up the names in the annotations.
* There are some new *true* positives in `attrs`, since we understand
the `Attribute` annotation that was previously inferred as `Unknown`
because of a re-assignment after the class definition.
## Test Plan
The existing attributes.md test suite has sufficient coverage here.
## Summary
Temporarily modify `UseDefMapBuilder::reachability` for star imports in
order for new definitions to pick up the right reachability. This was
already working for `UseDefMapBuilder::place_states`, but not for
`UseDefMapBuilder::reachable_definitions`.
closes https://github.com/astral-sh/ty/issues/728
## Test Plan
Regression test
## Summary
Evaluate `TYPE_CHECKING` to `ALWAYS_TRUE` and `not TYPE_CHECKING` to
`ALWAYS_FALSE` during semantic index building. This is a follow-up to
https://github.com/astral-sh/ruff/pull/18998 and is in principle just a
performance optimization. We see some (favorable) ecosystem changes
because we can eliminate definitely-unreachable branches early now and
retain narrowing constraints without solving
https://github.com/astral-sh/ty/issues/690 first.
## Summary
This just replaces one temporary solution to recursive protocols (the
`SelfReference` mechanism) with another one (track seen types when
recursively descending in `normalize` and replace recursive references
with `Any`). But this temporary solution can handle mutually-recursive
types, not just self-referential ones, and it's sufficient for the
primer ecosystem and some other projects we are testing on to no longer
stack overflow.
The follow-up here will be to properly handle these self-references
instead of replacing them with `Any`.
We will also eventually need cycle detection on more recursive-descent
type transformations and tests.
## Test Plan
Existing tests (including recursive-protocol tests) and primer.
Added mdtest for mutually-recursive protocols that stack-overflowed
before this PR.
## Summary
Simplifies literal `True` and `False` conditions to `ALWAYS_TRUE` /
`ALWAYS_FALSE` during semantic index building. This allows us to eagerly
evaluate more constraints, which should help with performance (looks
like there is a tiny 1% improvement in instrumented benchmarks), but
also allows us to eliminate definitely-unreachable branches in
control-flow merging. This can lead to better type inference in some
cases because it allows us to retain narrowing constraints without
solving https://github.com/astral-sh/ty/issues/690 first:
```py
def _(c: int | None):
if c is None:
assert False
reveal_type(c) # int, previously: int | None
```
closes https://github.com/astral-sh/ty/issues/713
## Test Plan
* Regression test for https://github.com/astral-sh/ty/issues/713
* Made sure that all ecosystem diffs trace back to removed false
positives
## Summary
This PR adds diagnostic for invalid binary operators in type
expressions. It should close https://github.com/astral-sh/ty/issues/706
if merged.
Please feel free to suggest better wordings for the diagnostic message.
## Test Plan
I modified `mdtest/annotations/invalid.md` and added a test for each
binary operator, and fixed tests that was broken by the new diagnostic.
This PR extracts a lot of the complex logic in the `match_parameters`
and `check_types` methods of our call binding machinery into separate
helper types. This is setup for #18996, which will update this logic to
handle variadic arguments. To do so, it is helpful to have the
per-argument logic extracted into a method that we can call repeatedly
for each _element_ of a variadic argument.
This should be a pure refactoring, with no behavioral changes.
This PR updates our unpacking assignment logic to use the new tuple
machinery. As a result, we can now unpack variable-length tuples
correctly.
As part of this, the `TupleSpec` classes have been renamed to `Tuple`,
and can now contain any element (Rust) type, not just `Type<'db>`. The
unpacker uses a tuple of `UnionBuilder`s to maintain the types that will
be assigned to each target, as we iterate through potentially many union
elements on the rhs. We also add a new consuming iterator for tuples,
and update the `all_elements` methods to wrap the result in an enum
(similar to `itertools::Position`) letting you know which part of the
tuple each element appears in. I also added a new
`UnionBuilder::try_build`, which lets you specify a different fallback
type if the union contains no elements.
## Summary
Ensure that we correctly infer calls such as `tuple((1, 2))`,
`tuple(range(42))`, etc. Ensure that we emit errors on invalid calls
such as `tuple[int, str]()`.
## Test Plan
Mdtests
Most of the work here was doing some light refactoring to facilitate
sensible testing. That is, we don't want to list every builtin included
in most tests, so we add some structure to the completion type returned.
Tests can now filter based on whether a completion is a builtin or not.
Otherwise, builtins are found using the existing infrastructure for
`object.attr` completions (where we hard-code the module name
`builtins`).
I did consider changing the sort order based on whether a completion
suggestion was a builtin or not. In particular, it seemed like it might
be a good idea to sort builtins after other scope based completions,
but before the dunder and sunder attributes. Namely, it seems likely
that there is an inverse correlation between the size of a scope and
the likelihood of an item in that scope being used at any given point.
So it *might* be a good idea to prioritize the likelier candidates in
the completions returned.
Additionally, the number of items introduced by adding builtins is quite
large. So I wondered whether mixing them in with everything else would
become too noisy.
However, it's not totally clear to me that this is the right thing to
do. Right now, I feel like there is a very obvious lexicographic
ordering that makes "finding" the right suggestion to activate
potentially easier than if the ranking mechanism is less clear.
(Technically, the dunder and sunder attributes are not sorted
lexicographically, but I'd put forward that most folks don't have an
intuitive understanding of where `_` ranks lexicographically with
respect to "regular" letters. Moreover, since dunder and sunder
attributes are all grouped together, I think the ordering here ends up
being very obvious after even a quick glance.)
## Summary
Setting `TY_MEMORY_REPORT=full` will generate and print a memory usage
report to the CLI after a `ty check` run:
```
=======SALSA STRUCTS=======
`Definition` metadata=7.24MB fields=17.38MB count=181062
`Expression` metadata=4.45MB fields=5.94MB count=92804
`member_lookup_with_policy_::interned_arguments` metadata=1.97MB fields=2.25MB count=35176
...
=======SALSA QUERIES=======
`File -> ty_python_semantic::semantic_index::SemanticIndex`
metadata=11.46MB fields=88.86MB count=1638
`Definition -> ty_python_semantic::types::infer::TypeInference`
metadata=24.52MB fields=86.68MB count=146018
`File -> ruff_db::parsed::ParsedModule`
metadata=0.12MB fields=69.06MB count=1642
...
=======SALSA SUMMARY=======
TOTAL MEMORY USAGE: 577.61MB
struct metadata = 29.00MB
struct fields = 35.68MB
memo metadata = 103.87MB
memo fields = 409.06MB
```
Eventually, we should integrate these numbers into CI in some form. The
one limitation currently is that heap allocations in salsa structs (e.g.
interned values) are not tracked, but memoized values should have full
coverage. We may also want a peak memory usage counter (that accounts
for non-salsa memory), but that is relatively simple to profile manually
(e.g. `time -v ty check`) and would require a compile-time option to
avoid runtime overhead.
## Summary
Format conflicting declared types as
```
`str`, `int` and `bytes`
```
Thanks to @AlexWaygood for the initial draft.
@dcreager, looking forward to your one-character follow-up PR.
## Summary
This PR includes a behavioral change to how we infer types for public
uses of symbols within a module. Where we would previously use the type
that a use at the end of the scope would see, we now consider all
reachable bindings and union the results:
```py
x = None
def f():
reveal_type(x) # previously `Unknown | Literal[1]`, now `Unknown | None | Literal[1]`
f()
x = 1
f()
```
This helps especially in cases where the the end of the scope is not
reachable:
```py
def outer(x: int):
def inner():
reveal_type(x) # previously `Unknown`, now `int`
raise ValueError
```
This PR also proposes to skip the boundness analysis of public uses.
This is consistent with the "all reachable bindings" strategy, because
the implicit `x = <unbound>` binding is also always reachable, and we
would have to emit "possibly-unresolved" diagnostics for every public
use otherwise. Changing this behavior allows common use-cases like the
following to type check without any errors:
```py
def outer(flag: bool):
if flag:
x = 1
def inner():
print(x) # previously: possibly-unresolved-reference, now: no error
```
closes https://github.com/astral-sh/ty/issues/210
closes https://github.com/astral-sh/ty/issues/607
closes https://github.com/astral-sh/ty/issues/699
## Follow up
It is now possible to resolve the following TODO, but I would like to do
that as a follow-up, because it requires some changes to how we treat
implicit attribute assignments, which could result in ecosystem changes
that I'd like to see separately.
315fb0f3da/crates/ty_python_semantic/src/semantic_index/builder.rs (L1095-L1117)
## Ecosystem analysis
[**Full report**](https://shark.fish/diff-public-types.html)
* This change obviously removes a lot of `possibly-unresolved-reference`
diagnostics (7818) because we do not analyze boundness for public uses
of symbols inside modules anymore.
* As the primary goal here, this change also removes a lot of
false-positive `unresolved-reference` diagnostics (231) in scenarios
like this:
```py
def _(flag: bool):
if flag:
x = 1
def inner():
x
raise
```
* This change also introduces some new false positives for cases like:
```py
def _():
x = None
x = "test"
def inner():
x.upper() # Attribute `upper` on type `Unknown | None | Literal["test"]`
is possibly unbound
```
We have test cases for these situations and it's plausible that we can
improve this in a follow-up.
## Test Plan
New Markdown tests
## Summary
This function is huge, and hugely indented. This PR breaks most of it
out into two helper functions: `KnownFunction::check_call()` and
`KnownClass::check_call`.
My immediate motivation is that we need to add yet more special cases to
this function in order to properly handle `tuple` instantiations and
instantiations of tuple subclasses. But I really don't relish the
thought of doing that with the function's current structure 😆
## Test Plan
Existing tests all pass. No new ones are added; this is a pure refactor
that should have no functional change.
## Summary
Add type narrowing inside comprehensions:
```py
def _(xs: list[int | None]):
[reveal_type(x) for x in xs if x is not None] # revealed: int
```
closes https://github.com/astral-sh/ty/issues/680
## Test Plan
* New Markdown tests
* Made sure the example from https://github.com/astral-sh/ty/issues/680
now checks without errors
* Made sure that all removed ecosystem diagnostics were actually false
positives
## Summary
Having a recursive type method to check whether a type is fully static
is inefficient, unnecessary, and makes us overly strict about subtyping
relations.
It's inefficient because we end up re-walking the same types many times
to check for fully-static-ness.
It's unnecessary because we can check relations involving the dynamic
type appropriately, depending whether the relation is subtyping or
assignability.
We use the subtyping relation to simplify unions and intersections. We
can usefully consider that `S <: T` for gradual types also, as long as
it remains true that `S | T` is equivalent to `T` and `S & T` is
equivalent to `S`.
One conservative definition (implemented here) that satisfies this
requirement is that we consider `S <: T` if, for every possible pair of
materializations `S'` and `T'`, `S' <: T'`. Or put differently the top
materialization of `S` (`S+` -- the union of all possible
materializations of `S`) is a subtype of the bottom materialization of
`T` (`T-` -- the intersection of all possible materializations of `T`).
In the most basic cases we can usefully say that `Any <: object` and
that `Never <: Any`, and we can handle more complex cases inductively
from there.
This definition of subtyping for gradual subtypes is not reflexive
(`Any` is not a subtype of `Any`).
As a corollary, we also remove `is_gradual_equivalent_to` --
`is_equivalent_to` now has the meaning that `is_gradual_equivalent_to`
used to have. If necessary, we could restore an
`is_fully_static_equivalent_to` or similar (which would not do an
`is_fully_static` pre-check of the types, but would instead pass a
relation-kind enum down through a recursive equivalence check, similar
to `has_relation_to`), but so far this doesn't appear to be necessary.
Credit to @JelleZijlstra for the observation that `is_fully_static` is
unnecessary and overly restrictive on subtyping.
There is another possible definition of gradual subtyping: instead of
requiring that `S+ <: T-`, we could instead require that `S+ <: T+` and
`S- <: T-`. In other words, instead of requiring all materializations of
`S` to be a subtype of every materialization of `T`, we just require
that every materialization of `S` be a subtype of _some_ materialization
of `T`, and that every materialization of `T` be a supertype of some
materialization of `S`. This definition also preserves the core
invariant that `S <: T` implies that `S | T = T` and `S & T = S`, and it
restores reflexivity: under this definition, `Any` is a subtype of
`Any`, and for any equivalent types `S` and `T`, `S <: T` and `T <: S`.
But unfortunately, this definition breaks transitivity of subtyping,
because nominal subclasses in Python use assignability ("consistent
subtyping") to define acceptable overrides. This means that we may have
a class `A` with `def method(self) -> Any` and a subtype `B(A)` with
`def method(self) -> int`, since `int` is assignable to `Any`. This
means that if we have a protocol `P` with `def method(self) -> Any`, we
would have `B <: A` (from nominal subtyping) and `A <: P` (`Any` is a
subtype of `Any`), but not `B <: P` (`int` is not a subtype of `Any`).
Breaking transitivity of subtyping is not tenable, so we don't use this
definition of subtyping.
## Test Plan
Existing tests (modified in some cases to account for updated
semantics.)
Stable property tests pass at a million iterations:
`QUICKCHECK_TESTS=1000000 cargo test -p ty_python_semantic -- --ignored
types::property_tests::stable`
### Changes to property test type generation
Since we no longer have a method of categorizing built types as
fully-static or not-fully-static, I had to add a previously-discussed
feature to the property tests so that some tests can build types that
are known by construction to be fully static, because there are still
properties that only apply to fully-static types (for example,
reflexiveness of subtyping.)
## Changes to handling of `*args, **kwargs` signatures
This PR "discovered" that, once we allow non-fully-static types to
participate in subtyping under the above definitions, `(*args: Any,
**kwargs: Any) -> Any` is now a subtype of `() -> object`. This is true,
if we take a literal interpretation of the former signature: all
materializations of the parameters `*args: Any, **kwargs: Any` can
accept zero arguments, making the former signature a subtype of the
latter. But the spec actually says that `*args: Any, **kwargs: Any`
should be interpreted as equivalent to `...`, and that makes a
difference here: `(...) -> Any` is not a subtype of `() -> object`,
because (unlike a literal reading of `(*args: Any, **kwargs: Any)`),
`...` can materialize to _any_ signature, including a signature with
required positional arguments.
This matters for this PR because it makes the "any two types are both
assignable to their union" property test fail if we don't implement the
equivalence to `...`. Because `FunctionType.__call__` has the signature
`(*args: Any, **kwargs: Any) -> Any`, and if we take that at face value
it's a subtype of `() -> object`, making `FunctionType` a subtype of `()
-> object)` -- but then a function with a required argument is also a
subtype of `FunctionType`, but not a subtype of `() -> object`. So I
went ahead and implemented the equivalence to `...` in this PR.
## Ecosystem analysis
* Most of the ecosystem report are cases of improved union/intersection
simplification. For example, we can now simplify a union like `bool |
(bool & Unknown) | Unknown` to simply `bool | Unknown`, because we can
now observe that every possible materialization of `bool & Unknown` is
still a subtype of `bool` (whereas before we would set aside `bool &
Unknown` as a not-fully-static type.) This is clearly an improvement.
* The `possibly-unresolved-reference` errors in sockeye, pymongo,
ignite, scrapy and others are true positives for conditional imports
that were formerly silenced by bogus conflicting-declarations (which we
currently don't issue a diagnostic for), because we considered two
different declarations of `Unknown` to be conflicting (we used
`is_equivalent_to` not `is_gradual_equivalent_to`). In this PR that
distinction disappears and all equivalence is gradual, so a declaration
of `Unknown` no longer conflicts with a declaration of `Unknown`, which
then results in us surfacing the possibly-unbound error.
* We will now issue "redundant cast" for casting from a typevar with a
gradual bound to the same typevar (the hydra-zen diagnostic). This seems
like an improvement.
* The new diagnostics in bandersnatch are interesting. For some reason
primer in CI seems to be checking bandersnatch on Python 3.10 (not yet
sure why; this doesn't happen when I run it locally). But bandersnatch
uses `enum.StrEnum`, which doesn't exist on 3.10. That makes the `class
SimpleDigest(StrEnum)` a class that inherits from `Unknown` (and
bypasses our current TODO handling for accessing attributes on enum
classes, since we don't recognize it as an enum class at all). This PR
improves our understanding of assignability to classes that inherit from
`Any` / `Unknown`, and we now recognize that a string literal is not
assignable to a class inheriting `Any` or `Unknown`.
Add property test generators for the new variable-length tuples. This
covers homogeneous tuples as well.
The property tests did their job! This identified several fixes we
needed to make to various type property methods.
cf https://github.com/astral-sh/ruff/pull/18600#issuecomment-2993764471
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Previously, the checks for implicit attribute assignments didn't
properly account for method decorators. This PR fixes that by:
- Adding a decorator check in `implicit_instance_attribute`. This allows
it to filter out methods with mismatching decorators when analyzing
attribute assignments.
- Adding attribute search for implicit class attributes: if an attribute
can't be found directly in the class body, the
`ClassLiteral::own_class_member` function will now search in
classmethods.
- Adding `staticmethod`: it has been added into `KnownClass` and
together with the new decorator check, it will no longer expose
attributes when the assignment target name is the same as the first
method name.
If accepted, it should fix https://github.com/astral-sh/ty/issues/205
and https://github.com/astral-sh/ty/issues/207.
## Test Plan
This is tested with existing mdtest suites and is able to get most of
the TODO marks for implicit assignments in classmethods and
staticmethods removed.
However, there's one specific test case I failed to figure out how to
correctly resolve:
b279508bdc/crates/ty_python_semantic/resources/mdtest/attributes.md?plain=1#L754-L755
I tried to add `instance_member().is_unbound()` check in this [else
branch](b279508bdc/crates/ty_python_semantic/src/types/infer.rs (L3299-L3301))
but it causes tests with class attributes defined in class body to fail.
While it's possible to implicitly add `ClassVar` to qualifiers to make
this assignment fail and keep everything else passing, it doesn't feel
like the right solution.
## Summary
This PR fixesastral-sh/ty#185 by avoiding to infer the value expression
for an unpacking.
This is done simply by only inferring the value expression in a
non-unpacking branch for assignment statement, for statement, with
statement and comprehensions.
This is a simpler alternative to
https://github.com/astral-sh/ruff/pull/18890 which I only realized in
hindsight! Ideally, the solution would to consider the "unpack" as it's
own region and do all of the inference of every expressions involved in
an unpacking inside the unpack query and then merge the results in the
outer query. This would require access to the `Unpack` ingredient which
is stored on the `Definition`. And, this would require create the said
`Definition`s for all attributes and subscript expressions. It does
simplify the target inference logic by streamlining it into a single
`infer_target` method instead of the `infer_target`/`infer_target_impl`
split.
Additionally, #18890 also solves a couple of TODOs around raising errors
around attribute / subscript assignment.
## Test Plan
Update the existing test, go through a couple of ecosystem diagnostic.
## Summary
Note this modifies the diagnostics a bit. Previously performing
subscript access on something like `NotSubscriptable1 |
NotSubscriptable2` would report the full type as not being
subscriptable:
```
[non-subscriptable] "Cannot subscript object of type `NotSubscriptable1 | NotSubscriptable2` with no `__getitem__` method"
```
Now each erroneous constituent has a separate error:
```
[non-subscriptable] "Cannot subscript object of type `NotSubscriptable2` with no `__getitem__` method"
[non-subscriptable] "Cannot subscript object of type `NotSubscriptable1` with no `__getitem__` method"
```
Closes https://github.com/astral-sh/ty/issues/625
## Test Plan
mdtest
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
There were two main challenges in this PR.
The first was mostly just figuring out how to get the symbols
corresponding to `module`. It turns out that we do this in a couple
of places in ty already, but through different means. In one approach,
we use [`exported_names`]. In another approach, we get a `Type`
corresponding to the module. We take the latter approach here, which is
consistent with how we do completions elsewhere. (I looked into
factoring this logic out into its own function, but it ended up being
pretty constrained. e.g., There's only one other place where we want to
go from `ast::StmtImportFrom` to a module `Type`, and that code also
wants the module name.)
The second challenge was recognizing the `from module import <CURSOR>`
pattern in the code. I initially started with some fixed token patterns
to get a proof of concept working. But I ended up switching to mini
state machine over tokens. I looked at the parser for `StmtImportFrom`
to determine what kinds of tokens we can expect.
[`exported_names`]:
23a3b6ef23/crates/ty_python_semantic/src/semantic_index/re_exports.rs (L47)
## Summary
As far as I can tell, the two existing tests did the exact same thing.
Remove the redundant test, and add tests for all combinations of
declared/not-declared and local/"public" use of the name.
Proposing this as a separate PR before the behavior might change via
https://github.com/astral-sh/ruff/pull/18750
## Summary
The code in the `Variable` branch of
`VariableLengthTupleSpec::has_relation_to` made the incorrect assumption
that if you zip two possibly-different-length iterators together and
iterate over the resulting zip iterator, the original two iterators will
only have their common elements consumed. But in fact, the zip iterator
detects that it is done when it receives a `None` from one iterator and
`Some()` element from the other iterator, which means that it consumes
one additional element from the longer iterator. This meant that we
failed to detect mismatched types on this extra consumed element,
because we never compared it to the variable type of the other tuple.
Use `zip_longest` from itertools as an alternative, which allows us to
combine all the handling into just two `zip_longest`, one for prefixes
and one for suffixes.
Marking this PR internal since it fixes a bug in a commit that wasn't
released yet.
## Test Plan
Added mdtests that failed before this fix and pass after it.
## Summary
Fixes https://github.com/astral-sh/ty/issues/640. If a user passes
`--python=<some-virtual-environment>/bin/python`, we must avoid
canonicalizing the path until we've traversed upwards to find the
`sys.prefix` directory (`<some-virtual-environment>`). On Unix systems,
`<sys.prefix>/bin/python` is often a symlink to a system interpreter; if
we resolve the symlink too easily then we'll add the system
interpreter's `site-packages` directory as a search path rather than the
virtual environment's directory.
## Test Plan
I added an integration test to
`crates/ty/tests/cli/python_environment.rs` which fails on `main`. I
also manually tested locally that running `cargo run -p ty check foo.py
--python=.venv/bin/python -vv` now prints this log to the terminal
```
2025-06-20 18:35:24.57702 DEBUG Resolved site-packages directories for this virtual environment are: SitePackagesPaths({"/Users/alexw/dev/ruff/.venv/lib/python3.13/site-packages"})
```
Whereas it previously resolved `site-packages` to my system
intallation's `site-packages` directory
We already had support for homogeneous tuples (`tuple[int, ...]`). This
PR extends this to also support mixed tuples (`tuple[str, str,
*tuple[int, ...], str str]`).
A mixed tuple consists of a fixed-length (possibly empty) prefix and
suffix, and a variable-length portion in the middle. Every element of
the variable-length portion must be of the same type. A homogeneous
tuple is then just a mixed tuple with an empty prefix and suffix.
The new data representation uses different Rust types for a fixed-length
(aka heterogeneous) tuple. Another option would have been to use the
`VariableLengthTuple` representation for all tuples, and to wrap the
"variable + suffix" portion in an `Option`. I don't think that would
simplify the method implementations much, though, since we would still
have a 2×2 case analysis for most of them.
One wrinkle is that the definition of the `tuple` class in the typeshed
has a single typevar, and canonically represents a homogeneous tuple.
When getting the class of a tuple instance, that means that we have to
summarize our detailed mixed tuple type information into its
"homogeneous supertype". (We were already doing this for heterogeneous
types.)
A similar thing happens when concatenating two mixed tuples: the
variable-length portion and suffix of the LHS, and the prefix and
variable-length portion of the RHS, all get unioned into the
variable-length portion of the result. The LHS prefix and RHS suffix
carry through unchanged.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Add support for `@staticmethod`s. Overall, the changes are very similar
to #16305.
#18587 will be dependent on this PR for a potential fix of
https://github.com/astral-sh/ty/issues/207.
mypy_primer will look bad since the new code allows ty to check more
code.
## Test Plan
Added new markdown tests. Please comment if there's any missing tests
that I should add in, thank you.
## Summary
This PR resolves the way diagnostics are reported for an invalid call to
an overloaded function.
If any of the steps in the overload call evaluation algorithm yields a
matching overload but it's type checking that failed, the
`no-matching-overload` diagnostic is incorrect because there is a
matching overload, it's the arguments passed that are invalid as per the
signature. So, this PR improves that by surfacing the diagnostics on the
matching overload directly.
It also provides additional context, specifically the matching overload
where this error occurred and other non-matching overloads. Consider the
following example:
```py
from typing import overload
@overload
def f() -> None: ...
@overload
def f(x: int) -> int: ...
@overload
def f(x: int, y: int) -> int: ...
def f(x: int | None = None, y: int | None = None) -> int | None:
return None
f("a")
```
We get:
<img width="857" alt="Screenshot 2025-06-18 at 11 07 10"
src="https://github.com/user-attachments/assets/8dbcaf13-2a74-4661-aa94-1225c9402ea6"
/>
## Test Plan
Update test cases, resolve existing todos and validate the updated
snapshots.
## Summary
Part of [#111](https://github.com/astral-sh/ty/issues/111).
After this change, dataclasses with two or more `KW_ONLY` field will be
reported as invalid. The duplicate fields will simply be ignored when
computing `__init__`'s signature.
## Test Plan
Markdown tests.
## Summary
Closes: astral-sh/ty#552
This PR adds support for step 5 of the overload call evaluation
algorithm which specifies:
> For all arguments, determine whether all possible materializations of
the argument’s type are
> assignable to the corresponding parameter type for each of the
remaining overloads. If so,
> eliminate all of the subsequent remaining overloads.
The algorithm works in two parts:
1. Find out the participating parameter indexes. These are the
parameters that aren't gradual equivalent to one or more parameter types
at the same index in other overloads.
2. Loop over each overload and check whether that would be the _final_
overload for the argument types i.e., the remaining overloads will never
be matched against these argument types
For step 1, the participating parameter indexes are computed by just
comparing whether all the parameter types at the corresponding index for
all the overloads are **gradual equivalent**.
The step 2 of the algorithm used is described in [this
comment](https://github.com/astral-sh/ty/issues/552#issuecomment-2969165421).
## Test Plan
Update the overload call tests.
## Summary
This PR closesastral-sh/ty#164.
This PR introduces a basic type narrowing mechanism for
attribute/subscript expressions.
Member accesses, int literal subscripts, string literal subscripts are
supported (same as mypy and pyright).
## Test Plan
New test cases are added to `mdtest/narrow/complex_target.md`.
---------
Co-authored-by: David Peter <mail@david-peter.de>
## Summary
* Completely removes the concept of visibility constraints. Reachability
constraints are now used to model the static visibility of bindings and
declarations. Reachability constraints are *much* easier to reason about
/ work with, since they are applied at the beginning of a branch, and
not applied retroactively. Removing the duplication between visibility
and reachability constraints also leads to major code simplifications
[^1]. For an overview of how the new constraint system works, see the
updated doc comment in `reachability_constraints.rs`.
* Fixes a [control-flow modeling bug
(panic)](https://github.com/astral-sh/ty/issues/365) involving `break`
statements in loops
* Fixes a [bug where](https://github.com/astral-sh/ty/issues/624) where
`elif` branches would have wrong reachability constraints
* Fixes a [bug where](https://github.com/astral-sh/ty/issues/648) code
after infinite loops would not be considered unreachble
* Fixes a panic on the `pywin32` ecosystem project, which we should be
able to move to `good.txt` once this has been merged.
* Removes some false positives in unreachable code because we infer
`Never` more often, due to the fact that reachability constraints now
apply retroactively to *all* active bindings, not just to bindings
inside a branch.
* As one example, this removes the `division-by-zero` diagnostic from
https://github.com/astral-sh/ty/issues/443 because we now infer `Never`
for the divisor.
* Supersedes and includes similar test changes as
https://github.com/astral-sh/ruff/pull/18392
closes https://github.com/astral-sh/ty/issues/365
closes https://github.com/astral-sh/ty/issues/624
closes https://github.com/astral-sh/ty/issues/642
closes https://github.com/astral-sh/ty/issues/648
## Benchmarks
Benchmarks on black, pandas, and sympy showed that this is neither a
performance improvement, nor a regression.
## Test Plan
Regression tests for:
- [x] https://github.com/astral-sh/ty/issues/365
- [x] https://github.com/astral-sh/ty/issues/624
- [x] https://github.com/astral-sh/ty/issues/642
- [x] https://github.com/astral-sh/ty/issues/648
[^1]: I'm afraid this is something that @carljm advocated for since the
beginning, and I'm not sure anymore why we have never seriously tried
this before. So I suggest we do *not* attempt to do a historical deep
dive to find out exactly why this ever became so complicated, and just
enjoy the fact that we eventually arrived here.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
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