## 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](1388252408):
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
--
Closes#19014 by identifying more `field` functions from `attrs`. We
already detected these when imported from `attrs` but not the `attr`
module from the same package. These functions are identical to the
`attrs` versions:
```pycon
>>> import attrs, attr
>>> attrs.field is attr.field
True
>>> attrs.Factory is attr.Factory
True
>>>
```
Test Plan
--
Regression tests based on the issue
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [pytest-incorrect-mark-parentheses-style
(PT023)](https://docs.astral.sh/ruff/rules/pytest-incorrect-mark-parentheses-style/#pytest-incorrect-mark-parentheses-style-pt023)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/48989153-6d4a-493a-a287-07f330f270bc)
```py
import pytest
@pytest.mark.foo
def test_something(): ...
```
[New example](https://play.ruff.rs/741f4d19-4607-4777-a77e-4ea6c62845e1)
```py
import pytest
@pytest.mark.foo()
def test_something(): ...
```
This just swaps the parenthesis in the "Example" and "Use instead"
sections since the default configuration is no parenthesis
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [pytest-warns-too-broad
(PT030)](https://docs.astral.sh/ruff/rules/pytest-warns-too-broad/#pytest-warns-too-broad-pt030)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/2296ae7e-c775-427a-a020-6fb25321f3f7)
```py
import pytest
def test_foo():
with pytest.warns(RuntimeWarning):
...
# empty string is also an error
with pytest.warns(RuntimeWarning, match=""):
...
```
[New example](https://play.ruff.rs/af35a482-1c2f-47ee-aff3-ff1e9fa447de)
```py
import pytest
def test_foo():
with pytest.warns(Warning):
...
# empty string is also an error
with pytest.warns(Warning, match=""):
...
```
`RuntimeWarning` is not in the default
[warns-require-match-for](https://docs.astral.sh/ruff/settings/#lint_flake8-pytest-style_warns-require-match-for)
list, while `Warning` is. The "Use instead" section was also updated
similarly
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [avoidable-escaped-quote
(Q003)](https://docs.astral.sh/ruff/rules/avoidable-escaped-quote/#avoidable-escaped-quote-q003)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/fb319d0f-8016-46a1-b6bb-42b1b054feea)
```py
foo = 'bar\'s'
```
[New example](https://play.ruff.rs/d9626561-0646-448f-9282-3f0691b90831)
```py
foo = "bar\"s"
```
The original example got overwritten by `Q000`, since double quotes is
the default config. The quotes were also switched in the "Use instead"
section.
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [enumerate-for-loop
(SIM113)](https://docs.astral.sh/ruff/rules/enumerate-for-loop/#enumerate-for-loop-sim113)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/a6ef6fec-eb6b-477c-a962-616f0b8e1491)
```py
fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
print(f"{i + 1}. {fruit}")
i += 1
```
[New example](https://play.ruff.rs/1811d608-1aa0-45d8-96dc-18105e74b8cc)
```py
fruits = ["apple", "banana", "cherry"]
i = 0
for fruit in fruits:
print(f"{i + 1}. {fruit}")
i += 1
```
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [enumerate-for-loop [if-else-block-instead-of-dict-get
(SIM401)](https://docs.astral.sh/ruff/rules/if-else-block-instead-of-dict-get/#if-else-block-instead-of-dict-get-sim401)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/635629eb-7146-45a8-9e0c-4a0aa9446ded)
```py
if "bar" in foo:
value = foo["bar"]
else:
value = 0
```
[New example](https://play.ruff.rs/a1227ec9-05c2-4a22-800d-c76cb7abe249)
```py
foo = {}
if "bar" in foo:
value = foo["bar"]
else:
value = 0
```
The "Use instead" section was also updated similarly.
The docs for `SIM401` also has another section on the preview ternary
version, but it does not seem to check that the variable is a dict
(bug?) https://play.ruff.rs/c0feada8-a7fe-43f7-b57e-c10520fdcdca
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [reimplemented-builtin
(SIM110)](https://docs.astral.sh/ruff/rules/reimplemented-builtin/#reimplemented-builtin-sim110)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/1c192e8b-13f8-4f07-8c35-9dcd516a4a02)
```py
for item in iterable:
if predicate(item):
return True
return False
```
[New example](https://play.ruff.rs/f77393ad-20b1-436f-a872-d3bccec7c829)
```py
def foo():
for item in iterable:
if predicate(item):
return True
return False
```
The "Use instead" section was also updated to reflect the change.
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
The benchmark is currently very noisy (± 10%). This leads to codspeed
reports on PRs, because we often exceed the trigger threshold. This is
confusing to ty contributors who are not aware about the flakiness.
Let's disable it for now.
## Summary
This PR adds initial support for workspace diagnostics in the ty server.
Reference spec:
https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#workspace_diagnostic
This is currently implemented via the **pull diagnostics method** which
was added in the current version (3.17) and the server advertises it via
the `diagnosticProvider.workspaceDiagnostics` server capability.
**Note:** This might be a bit confusing but a workspace diagnostics is
not for a single workspace but for all the workspaces that the server
handles. These are the ones that the server received during
initialization. Currently, the ty server doesn't support multiple
workspaces so this capability is also limited to provide diagnostics
only for a single workspace (the first one if the client provided
multiple).
A new `ty.diagnosticMode` server setting is added which can be either
`workspace` (for workspace diagnostics) or `openFilesOnly` (for checking
only open files) (default). This is same as
`python.analysis.diagnosticMode` that Pyright / Pylance utilizes. In the
future, we could use the value under `python.*` namespace as fallback to
improve the experience on user side to avoid setting the value multiple
times.
Part of: astral-sh/ty#81
## Test Plan
This capability was introduced in the current LSP version (~3 years) and
the way it's implemented by various clients are a bit different. I've
provided notes on what I've noticed and what would need to be done on
our side to further improve the experience.
### VS Code
VS Code sends the `workspace/diagnostic` requests every ~2 second:
```
[Trace - 12:12:32 PM] Sending request 'workspace/diagnostic - (403)'.
[Trace - 12:12:32 PM] Received response 'workspace/diagnostic - (403)' in 2ms.
[Trace - 12:12:34 PM] Sending request 'workspace/diagnostic - (404)'.
[Trace - 12:12:34 PM] Received response 'workspace/diagnostic - (404)' in 2ms.
[Trace - 12:12:36 PM] Sending request 'workspace/diagnostic - (405)'.
[Trace - 12:12:36 PM] Received response 'workspace/diagnostic - (405)' in 2ms.
[Trace - 12:12:38 PM] Sending request 'workspace/diagnostic - (406)'.
[Trace - 12:12:38 PM] Received response 'workspace/diagnostic - (406)' in 3ms.
[Trace - 12:12:40 PM] Sending request 'workspace/diagnostic - (407)'.
[Trace - 12:12:40 PM] Received response 'workspace/diagnostic - (407)' in 2ms.
...
```
I couldn't really find any resource that explains this behavior. But,
this does mean that we'd need to implement the caching layer via the
previous result ids sooner. This will allow the server to avoid sending
all the diagnostics on every request and instead just send a response
stating that the diagnostics hasn't changed yet. This could possibly be
achieved by using the salsa ID.
If we switch from workspace diagnostics to open-files diagnostics, the
server would send the diagnostics only via the `textDocument/diagnostic`
endpoint. Here, when a document containing the diagnostic is closed, the
server would send a publish diagnostics notification with an empty list
of diagnostics to clear the diagnostics from that document. The issue is
the VS Code doesn't seem to be clearing the diagnostics in this case
even though it receives the notification. (I'm going to open an issue on
VS Code side for this today.)
https://github.com/user-attachments/assets/b0c0833d-386c-49f5-8a15-0ac9133e15ed
### Zed
Zed's implementation works by refreshing the workspace diagnostics
whenever the content of the documents are changed. This seems like a
very reasonable behavior and I was a bit surprised that VS Code didn't
use this heuristic.
https://github.com/user-attachments/assets/71c7b546-7970-434a-9ba0-4fa620647f6c
### Neovim
Neovim only recently added support for workspace diagnostics
(https://github.com/neovim/neovim/pull/34262, merged ~3 weeks ago) so
it's only available on nightly versions.
The initial support is limited and requires fetching the workspace
diagnostics manually as demonstrated in the video. It doesn't support
refreshing the workspace diagnostics either, so that would need to be
done manually as well. I'm assuming that these are just a temporary
limitation and will be implemented before the stable release.
https://github.com/user-attachments/assets/25b4a0e5-9833-4877-88ad-279904fffaf9
## Summary
This PR adds a new trait to support running a request in the background.
Currently, there exists a `BackgroundDocumentRequestHandler` trait which
is similar but is scoped to a specific document (file in an editor
context). The new trait `BackgroundRequestHandler` is not tied to a
specific document nor a specific project but it's for the entire
workspace.
This is added to support running workspace wide requests like computing
the [workspace
diagnostics](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#workspace_diagnostic)
or [workspace
symbols](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#workspace_symbol).
**Note:** There's a slight difference with what a "workspace" means
between the server and ty. Currently, there's a 1-1 relationship between
a workspace in an editor and the project database corresponding to that
workspace in ty but this could change in the future when Micha adds
support for multiple workspaces or multi-root workspaces.
The data that would be required by the request handler (based on
implementing workspace diagnostics) is the list of databases
(`ProjectDatabse`) corresponding to the projects in the workspace and
the index (`Index`) that contains the open documents. The
`WorkspaceSnapshot` represents this and is passed to the handler similar
to `DocumentSnapshot`.
## Test Plan
This is used in implementing the workspace diagnostics which is where
this is tested.
## 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`
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [snake-case-type-alias
(PYI042)](https://docs.astral.sh/ruff/rules/snake-case-type-alias/#snake-case-type-alias-pyi042)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/8fafec81-2228-4ffe-81e8-1989b724cb47)
```py
type_alias_name: TypeAlias = int
```
[New example](https://play.ruff.rs/b396746c-e6d2-423c-bc13-01a533bb0747)
```py
from typing import TypeAlias
type_alias_name: TypeAlias = int
```
Imports were also added to the "use instead" section.
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
This fixes the docs for [expressions-in-star-assignment
(F621)](https://docs.astral.sh/ruff/rules/expressions-in-star-assignment/#expressions-in-star-assignment-f621)
having a backslash `\` before the left shifts `<<`. I'm not sure why
this happened in the first place, as the docstring looks fine, but
putting the `<<` inside a code block fixes it. I was not able to track
down the source of the issue either. The only other rule with a `<<` is
[missing-whitespace-around-bitwise-or-shift-operator
(E227)](https://docs.astral.sh/ruff/rules/missing-whitespace-around-bitwise-or-shift-operator/#missing-whitespace-around-bitwise-or-shift-operator-e227),
which already has it in a code block.
Old docs page:
> In Python 3, no more than 1 \\<< 8 assignments are allowed before a
starred expression, and no more than 1 \\<< 24 expressions are allowed
after a starred expression.
New docs page:
> In Python 3, no more than `1 << 8` assignments are allowed before a
starred expression, and no more than `1 << 24` expressions are allowed
after a starred expression.
## Test Plan
<!-- How was it tested? -->
N/A, no tests/functionality affected.
## 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
This PR updates Salsa to pull in Ibraheem's multithreading improvements (https://github.com/salsa-rs/salsa/pull/921).
## Performance
A small regression for single-threaded benchmarks is expected because
papaya is slightly slower than a `Mutex<FxHashMap>` in the uncontested
case (~10%). However, this shouldn't matter as much in practice because:
1. Salsa has a fast-path when only using 1 DB instance which is the
common case in production. This fast-path is not impacted by the changes
but we measure the slow paths in our benchmarks (because we use multiple
db instances)
2. Fixing the 10x slowdown for the congested case (multi threading)
outweights the downsides of a 10% perf regression for single threaded
use cases, especially considering that ty is heavily multi threaded.
## Test Plan
`cargo test`
## Summary
Extracts the vendored typeshed stubs lazily and caches them on the local
filesystem to support go-to in the LSP.
Resolves https://github.com/astral-sh/ty/issues/77.
## Summary
This PR makes the necessary changes to the server that it can request
configurations from the client using the `configuration` request.
This PR doesn't make use of the request yet. It only sets up the
foundation (mainly the coordination between client and server)
so that future PRs could pull specific settings.
I plan to use this for pulling the Python environment from the Python
extension.
Deno does something very similar to this.
## Test Plan
Tested that diagnostics are still shown.
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [duplicate-literal-member
(PYI062)](https://docs.astral.sh/ruff/rules/duplicate-literal-member/#duplicate-literal-member-pyi062)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/6b00b41c-c1c5-4421-873d-fc2a143e7337)
```py
foo: Literal["a", "b", "a"]
```
[New example](https://play.ruff.rs/1aea839b-9ae8-4848-bb83-2637e1a68ce4)
```py
from typing import Literal
foo: Literal["a", "b", "a"]
```
Imports were also added to the "use instead" section.
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
Follow-up to https://github.com/astral-sh/ruff/pull/19083, also log the
target names like `ty_python_semantic::module_resolver::resolver` in
`2025-07-02 10:12:20.188697000 DEBUG
ty_python_semantic::module_resolver::resolver: Adding first-party search
path '/Users/dhruv/playground/ty_server'` at trace level.
## 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? -->
https://github.com/ankitects/anki/pull/4119
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Add Anki to Who's Using Ruff (README)
---------
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
This PR fixes#19047 / the [isinstance-type-none
(FURB168)](https://docs.astral.sh/ruff/rules/isinstance-type-none/#isinstance-type-none-furb168)
tuple false positive by adding a check if the tuple is empty to the
code. I also noticed there was another false positive with the other
tuple check in the same function, so I fixed it the same way.
`Union[()]` is invalid at runtime with `TypeError: Cannot take a Union
of no types.`, but it is accepted by `basedpyright`
[playground](https://basedpyright.com/?pythonVersion=3.8&typeCheckingMode=all&code=GYJw9gtgBALgngBwJYDsDmUkQWEMoCqKSYKAsAFAgCmAbtQIYA2A%2BvAtQBREkoDanAJQBdQUA)
and is equivalent to `Never`, so I fixed it anyways. I'm getting on a
side tangent here, but it looks like MyPy doesn't accept it, and ty
[playground](https://play.ty.dev/c2c468b6-38e4-4dd9-a9fa-0276e843e395)
gives `@Todo`.
## Test Plan
<!-- How was it tested? -->
Added two test cases for the two false positives.
[playground](https://play.ruff.rs/a53afc21-9a1d-4b9b-9346-abfbeabeb449)
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [datetime-min-max
(DTZ901)](https://docs.astral.sh/ruff/rules/datetime-min-max/#datetime-min-max-dtz901)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/c1202727-1a18-4d3f-92a4-334ede07ed3e)
```py
datetime.max
```
[New example](https://play.ruff.rs/af2c76aa-9beb-46bc-8e27-faf53ecdbe8c)
```py
import datetime
datetime.datetime.max
```
I also added imports to the problem demonstration and use instead.
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
## 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.
