## Summary
For something like this:
```py
from typing import Callable
def my_lossy_decorator(fn: Callable[..., int]) -> Callable[..., int]:
return fn
class MyClass:
@my_lossy_decorator
def method(self) -> int:
return 42
```
we will currently infer the type of `MyClass.method` as a function-like
`Callable`, but we will infer the type of `MyClass().method` as a
`Callable` that is _not_ function-like. That's because a `CallableType`
currently "forgets" whether it was function-like or not during the
`bound_self` transformation:
a57e291311/crates/ty_python_semantic/src/types.rs (L10985-L10987)
This seems incorrect, and it's quite different to what we do when
binding the `self` parameter of `FunctionLiteral` types: `BoundMethod`
types are all seen as subtypes of function-like `Callable` supertypes --
here's `BoundMethodType::into_callable_type`:
a57e291311/crates/ty_python_semantic/src/types.rs (L10844-L10860)
The bug here is also causing lots of false positives in the ecosystem
report on https://github.com/astral-sh/ruff/pull/21611: a decorated
method on a subclass is currently not seen as validly overriding an
undecorated method with the same signature on a superclass, because the
undecorated superclass method is seen as function-like after binding
`self` whereas the decorated subclass method is not.
Fixing the bug required adding a new API in `protocol_class.rs`, because
it turns out that for our purposes in protocol subtyping/assignability,
we really do want a callable type to forget its function-like-ness when
binding `self`.
I initially tried out this change without changing anything in
`protocol_class.rs`. However, it resulted in many ecosystem false
positives and new false positives on the typing conformance test suite.
This is because it would mean that no protocol with a `__call__` method
would ever be seen as a subtype of a `Callable` type, since the
`__call__` method on the protocol would be seen as being function-like
whereas the `Callable` type would not be seen as function-like.
## Test Plan
Added an mdtest that fails on `main`
Before, we would collapse any constraint of the form `Never ≤ T ≤
object` down to the "always true" constraint set. This is correct in
terms of BDD semantics, but loses information, since "not constraining a
typevar at all" is different than "constraining a typevar to take on any
type". Once we get to specialization inference, we should fall back on
the typevar's default for the former, but not for the latter.
This is much easier to support now that we have a sequent map, since we
need to treat `¬(Never ≤ T ≤ object)` as being impossible, and prune it
when we walk through BDD paths, just like we do for other impossible
combinations.
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## Summary
Resolves
https://github.com/astral-sh/ty/issues/317#issuecomment-3567398107.
I can't get the auto import working great.
I haven't added many places where we specify that the type display is
invalid syntax.
## Test Plan
Nothing yet
This patch updates our protocol assignability checks to substitute for
any occurrences of `typing.Self` in method signatures, replacing it with
the class being checked for assignability against the protocol.
This requires a new helper method on signatures, `apply_self`, which
substitutes occurrences of `typing.Self` _without_ binding the `self`
parameter.
We also update the `try_upcast_to_callable` method. Before, it would
return a `Type`, since certain types upcast to a _union_ of callables,
not to a single callable. However, even in that case, we know that every
element of the union is a callable. We now return a vector of
`CallableType`. (Actually a smallvec to handle the most common case of a
single callable; and wrapped in a new type so that we can provide helper
methods.) If there is more than one element in the result, it represents
a union of callables. This lets callers get at the `CallableType`
instances in a more type-safe way. (This makes it easier for our
protocol checking code to call the new `apply_self` helper.) We also
provide an `into_type` method so that callers that really do want a
`Type` can get the original result easily.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
This only applies to items that have a type associated with them. That
is, things that are already in scope. For items that don't have a type
associated with them (i.e., suggestions from auto-import), we still
suggest them since we can't know if they're appropriate or not. It's not
quite clear on how best to improve here for the auto-import case. (Short
of, say, asking for the type of each such symbol. But the performance
implications of that aren't known yet.)
Note that because of auto-import, we were still suggesting
`NotImplemented` even though astral-sh/ty#1262 specifically cites it as
the motivating example that we *shouldn't* suggest. This was occuring
because auto-import was including symbols from the `builtins` module,
even though those are actually already in scope. So this PR also gets
rid of those suggestions from auto-import.
Overall, this means that, at least, `raise NotImpl` won't suggest
`NotImplemented`.
Fixesastral-sh/ty#1262
## Summary
Fixes https://github.com/astral-sh/ty/issues/1620. #20909 added hints if
you do something like this and your Python version is set to 3.10 or
lower:
```py
import typing
typing.LiteralString
```
And we also have hints if you try to do something like this and your
Python version is set too low:
```py
from stdlib_module import new_submodule
```
But we don't currently have any subdiagnostic hint if you do something
like _this_ and your Python version is set too low:
```py
from typing import LiteralString
```
This PR adds that hint!
## Test Plan
snapshots
---------
Co-authored-by: Aria Desires <aria.desires@gmail.com>
## Summary
This PR adds a failing mdtest for the panic in
https://github.com/astral-sh/ty/issues/1587. The added snippet currently
panics with this query stacktrace:
```
error[panic]: Panicked at /Users/alexw/.cargo/git/checkouts/salsa-e6f3bb7c2a062968/17bc55d/src/function/execute.rs:321:21 when checking `/Users/alexw/dev/ruff/foo.py`: `ClassLiteral < 'db >::explicit_bases_(Id(4c09)): execute: too many cycle iterations`
info: This indicates a bug in ty.
info: If you could open an issue at https://github.com/astral-sh/ty/issues/new?title=%5Bpanic%5D, we'd be very appreciative!
info: Platform: macos aarch64
info: Version: ruff/0.14.5+105 (d24c891a4 2025-11-22)
info: Args: ["target/debug/ty", "check", "foo.py", "--python-version=3.14"]
info: run with `RUST_BACKTRACE=1` environment variable to show the full backtrace information
info: query stacktrace:
0: cached_protocol_interface(Id(6805))
at crates/ty_python_semantic/src/types/protocol_class.rs:795
1: is_equivalent_to_object_inner(Id(8003))
at crates/ty_python_semantic/src/types/instance.rs:667
2: infer_deferred_types(Id(1406))
at crates/ty_python_semantic/src/types/infer.rs:140
cycle heads: infer_definition_types(Id(140b)) -> iteration = 200, TypeVarInstance < 'db >::lazy_bound_(Id(5802)) -> iteration = 200
3: TypeVarInstance < 'db >::lazy_bound_(Id(5803))
at crates/ty_python_semantic/src/types.rs:8827
4: infer_definition_types(Id(140c))
at crates/ty_python_semantic/src/types/infer.rs:94
5: infer_deferred_types(Id(1405))
at crates/ty_python_semantic/src/types/infer.rs:140
6: TypeVarInstance < 'db >::lazy_bound_(Id(5802))
at crates/ty_python_semantic/src/types.rs:8827
7: infer_definition_types(Id(140b))
at crates/ty_python_semantic/src/types/infer.rs:94
8: infer_scope_types(Id(1000))
at crates/ty_python_semantic/src/types/infer.rs:70
9: check_file_impl(Id(c00))
at crates/ty_project/src/lib.rs:535
```
It's not totally clear to me how to fix this or to what extent it might
be a bug in our `Protocol` internals rather than a bug in our `TypeVar`
internals. (It's sort of interesting that we're trying to evaluate the
upper bound of any `TypeVar`s here!) @carljm suggested that it would be
a good idea to add a failing mdtest in the meantime to document the
panic, which I agree with.
## Test Plan
I verified that we panic on this snippet, and that the test fails if I
remove the `expect-panic` assertion or if I change the asserted error
message.
I experimented with ways of minimizing the snippet further, but I think
any further minimization takes the snippet further away from something a
user would actually be likely to write -- so I think is probably
counterproductive. The failing test added in this PR isn't unreasonable
code at the end of the day; I've seen Python like it in the wild.
## Summary
Fixes a panic when parsing IPython escape commands with `Help` kind
(`?`) in expression contexts. The parser now reports an error instead of
panicking.
Fixes#21465.
## Problem
The parser panicked with `unreachable!()` in
`parse_ipython_escape_command_expression` when encountering escape
commands with `Help` kind (`?`) in expression contexts, where only
`Magic` (`%`) and `Shell` (`!`) are allowed.
## Approach
Replaced the `unreachable!()` panic with error handling that adds a
`ParseErrorType::OtherError` and continues parsing, returning a valid
AST node with the error attached.
## Test Plan
Added `test_ipython_escape_command_in_with_statement` and
`test_ipython_help_escape_command_as_expression` to verify the fix.
---------
Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
* Fixes https://github.com/astral-sh/ty/issues/1011
* Also fixes the fact that we didn't handle `.x` properly *at all* in
hover/goto
It turns out all of our import handling completely ignored the `level`
(number of relative `.`'s) in a `from ..x.y import z` statement. It was
nice seeing how much my understanding of `ty` has improved -- previously
this would have all been opaque to me but now it was just, completely
glaring and blatant.
Fixing this required refactoring all the import code to take the
importing file into consideration. I ended up refactoring a bunch of
code to pass around/require `SemanticModel` more, as it's the natural
API for resolving this kind of import (it actually had an API for this
that was just... dead code, whoops!).
## Summary
As reported in #19757:
While attempting ISC003 autofix for an expression with explicit string
concatenation, with either operand being a string literal that wraps
across multiple lines (in parentheses) - it resulted in generating a fix
which caused runtime error.
Example:
```
_ = "abc" + (
"def"
"ghi"
)
```
was being auto-fixed to:
```
_ = "abc" (
"def"
"ghi"
)
```
which raised `TypeError: 'str' object is not callable`
This commit makes changes to just report diagnostic - no autofix in such
cases.
Fixes#19757.
## Test Plan
Added example scenarios in
`crates/ruff_linter/resources/test/fixtures/flake8_implicit_str_concat/ISC.py`.
Signed-off-by: Prakhar Pratyush <prakhar1144@gmail.com>
## Summary
Fixes the PLE1141 (`dict-iter-missing-items`) rule to allow fixes for
empty dictionaries unless they have type annotations indicating 2-tuple
keys. Previously, the fix was incorrectly suppressed for all empty dicts
due to vacuous truth in the `all()` function.
Fixes#21289
## Problem Analysis
The `is_dict_key_tuple_with_two_elements` function was designed to
suppress the fix when a dictionary's keys are all 2-tuples, as unpacking
tuple keys directly would change runtime behavior.
However, for empty dictionaries, `iter_keys()` returns an empty
iterator, and `all()` on an empty iterator returns `true` (vacuous
truth). This caused the function to incorrectly suppress fixes for empty
dicts, even when there was no indication that future keys would be
2-tuples.
## Approach
1. **Detect empty dictionaries**: Added a check to identify when a dict
literal has no keys.
2. **Handle annotated empty dicts**: For empty dicts with type
annotations:
- Parse the annotation to check if it's `dict[tuple[T1, T2], ...]` where
the tuple has exactly 2 elements
- Support both PEP 484 (`typing.Dict`, `typing.Tuple`) and PEP 585
(`dict`, `tuple`) syntax
- If tuple keys are detected, suppress the fix (correct behavior)
- Otherwise, allow the fix
3. **Handle unannotated empty dicts**: For empty dicts without
annotations, allow the fix since there's no indication that keys will be
2-tuples.
4. **Preserve existing behavior**: For non-empty dicts, the original
logic is unchanged - check if all existing keys are 2-tuples.
The implementation includes helper functions:
- `is_annotation_dict_with_tuple_keys()`: Checks if a type annotation
specifies dict with tuple keys
- `is_tuple_type_with_two_elements()`: Checks if a type expression
represents a 2-tuple
Test cases were added to verify:
- Empty dict without annotation triggers the error
- Empty dict with `dict[tuple[int, str], bool]` suppresses the error
- Empty dict with `dict[str, int]` triggers the error
- Existing tests remain unchanged
---------
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
PR #21549 introduced a subtle overflow bug that seemed impossible, but
can empirically happen. This PR fixes it by saturating to zero.
I did try to write a regression test for this, but couldn't manage it.
Instead, I'll attach before-and-after screen recordings.
These were added to try to make it clearer that assignability checks
will eventually return more detailed answers than true or false.
However, the constraint set display rendering is still more brittle than
I'd like it to be, and it's more trouble than it's worth to keep them
updated with semantically identically but textually different edits. The
`static_assert`s are sufficient to check correctness, and we can always
add `reveal_type` when needed for further debugging.
## Summary
Extends the `used-dummy-variable` rule
([RUF052](https://docs.astral.sh/ruff/rules/used-dummy-variable/)) to
detect dummy variables that are used within list comprehensions, dict
comprehensions, set comprehensions, and generator expressions, not just
regular for loops and function assignments.
### Problem
Previously, RUF052 only flagged dummy variables (variables with leading
underscores) that were used in function scopes via assignments or
regular for loops. It missed cases where dummy variables were used
within comprehensions:
```python
def example():
my_list = [{"foo": 1}, {"foo": 2}]
# These were not detected before:
[_item["foo"] for _item in my_list] # Should warn: _item is used
{_item["key"]: _item["val"] for _item in my_list} # Should warn: _item is used
(_item["foo"] for _item in my_list) # Should warn: _item is used
```
### Solution
- Extended scope checking to include all generator scopes () with any
(list/dict/set comprehensions and generator expressions)
`ScopeKind::Generator``GeneratorKind`
- Added support for bindings, which cover loop variables in both regular
for loops and comprehensions `BindingKind::LoopVar`
- Refactored the scope validation logic for better readability with a
descriptive variable `is_allowed_scope`
[ISSUE](https://github.com/astral-sh/ruff/issues/19732)
## Test Plan
```bash
cargo test
```
---------
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
Statements such as `def foo(p<CURSOR>`,
`def foo[T<CURSOR>` and `for foo<CURSOR>`
should not generate any suggestions as these
cases are introducing new names.
If it's not possible to determine that suggestions should be omitted
using token matching in an easy way, we turn
to traversing the AST to determine the context.
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## Summary
Fixes https://github.com/astral-sh/ty/issues/1563
It keeps using the existing token matching pattern for the easy cases
(nothing typed and most recent token is a definition token) and
fallbacks to AST traveral for the slightly more difficult cases where
token matching becomes difficult and error prone.
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## Test Plan
New test cases and sanity-checking in the ty playground
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## Summary
This introduces a very bad and naive
python-docstring-flavoured-reStructuredText to github-flavor-markdown
translator. The main goal is to try to preserve a lot of the formatting
and plaintext, progressively enhance the content when we find things we
know about, and escape the text when we find things that might get
corrupt.
Previously I'd broken this out into rendering each different format, but
with this approach you don't really need to?
## Test Plan
Lots of snapshot tests, also messed around in some random stdlib
modules.
This commit essentially does away of all our old heuristic and piecemeal
code for detecting different kinds of import statements. Instead, we
offer one single state machine that does everything. This on its own
fixes a few bugs. For example, `import collections.abc, unico<CURSOR>`
would previously offer global scope completions instead of module
completions.
For the most part though, this commit is a refactoring that preserves
parity. In the next commit, we'll add support for completions on
relative imports.
This is a small refactor that helps centralize the
logic for how we gather, convert and possibly filter
completions.
Some of this logic was spread out before, which
motivated this refactor. Moreover, as part of other
refactoring, I found myself chaffing against the
lack of this abstraction.
Refs https://github.com/astral-sh/ty/issues/544
## Summary
Takes a more incremental approach to PEP 613 type alias support (vs
https://github.com/astral-sh/ruff/pull/20107). Instead of eagerly
inferring the RHS of a PEP 613 type alias as a type expression, infer it
as a value expression, just like we do for implicit type aliases, taking
advantage of the same support for e.g. unions and other type special
forms.
The main reason I'm following this path instead of the one in
https://github.com/astral-sh/ruff/pull/20107 is that we've realized that
people do sometimes use PEP 613 type aliases as values, not just as
types (because they are just a normal runtime assignment, unlike PEP 695
type aliases which create an opaque `TypeAliasType`).
This PR doesn't yet provide full support for recursive type aliases
(they don't panic, but they just fall back to `Unknown` at the recursion
point). This is future work.
## Test Plan
Added mdtests.
Many new ecosystem diagnostics, mostly because we
understand new types in lots of places.
Conformance suite changes are correct.
Performance regression is due to understanding lots of new
types; nothing we do in this PR is inherently expensive.
This is a very conservative minimal implementation of applying overloads
to resolve a callable-type-being-called down to a single function
signature on hover. If we ever encounter a situation where the answer
doesn't simplify down to a single function call, we bail out to preserve
prettier printing of non-raw-Signatures.
The resulting Signatures are still a bit bare, I'm going to try to
improve that in a followup to improve our Signature printing in general.
Fixes https://github.com/astral-sh/ty/issues/73
As far as I know this change is largely non-functional, largely because
of https://github.com/astral-sh/ty/issues/1601
It's possible some of these like `Type::KnownInstance` produce something
useful sometimes. `LiteralString` is a new introduction, although its
goto-type jumps to `str` which is a bit sad (considering that part of
the SpecialForm discourse for now).
Also wrt the generics testing followup: turns out the snapshot tests
were full of those already.
## Summary
Eagerly evaluate the elements of a PEP 604 union in value position (e.g.
`IntOrStr = int | str`) as type expressions and store the result (the
corresponding `Type::Union` if all elements are valid type expressions,
or the first encountered `InvalidTypeExpressionError`) on the
`UnionTypeInstance`, such that the `Type::Union(…)` does not need to be
recomputed every time the implicit type alias is used in a type
annotation.
This might lead to performance improvements for large unions, but is
also necessary for correctness, because the elements of the union might
refer to type variables that need to be looked up in the scope of the
type alias, not at the usage site.
## Test Plan
New Markdown tests
This PR generalizes the signature_help system's SignatureWriter which
could get the subspans of function parameters.
We now have TypeDetailsWriter which is threaded between type's display
implementations via a new `fmt_detailed` method that many of the Display
types now have.
With this information we can properly add goto-type targets to our inlay
hints. This also lays groundwork for any future "I want to render a type
but get spans" work.
Also a ton of lifetimes are introduced to avoid things getting conflated
with `'db`.
This PR is broken up into a series of commits:
* Generalizing `SignatureWriter` to `TypeDetailsWriter`, but not using
it anywhere else. This commit was confirmed to be a non-functional
change (no test results changed)
* Introducing `fmt_detailed` everywhere to thread through
`TypeDetailsWriter` and annotate various spans as "being" a given Type
-- this is also where I had to reckon with a ton of erroneous `&'db
self`. This commit was also confirmed to be a non-functional change.
* Finally, actually using the results for goto-type on inlay hints!
* Regenerating snapshots, fixups, etc.
#21414 added the ability to create a specialization from a constraint
set. It handled mutually constrained typevars just fine, e.g. given `T ≤
int ∧ U = T` we can infer `T = int, U = int`.
But it didn't handle _nested_ constraints correctly, e.g. `T ≤ int ∧ U =
list[T]`. Now we do! This requires doing a fixed-point "apply the
specialization to itself" step to propagate the assignments of any
nested typevars, and then a cycle detection check to make sure we don't
have an infinite expansion in the specialization.
This gets at an interesting nuance in our constraint set structure that
@sharkdp has asked about before. Constraint sets are BDDs, and each
internal node represents an _individual constraint_, of the form `lower
≤ T ≤ upper`. `lower` and `upper` are allowed to be other typevars, but
only if they appear "later" in the arbitary ordering that we establish
over typevars. The main purpose of this is to avoid infinite expansion
for mutually constrained typevars.
However, that restriction doesn't help us here, because only applies
when `lower` and `upper` _are_ typevars, not when they _contain_
typevars. That distinction is important, since it means the restriction
does not affect our expressiveness: we can always rewrite `Never ≤ T ≤
U` (a constraint on `T`) into `T ≤ U ≤ object` (a constraint on `U`).
The same is not true of `Never ≤ T ≤ list[U]` — there is no "inverse" of
`list` that we could apply to both sides to transform this into a
constraint on a bare `U`.
## Summary
Updated `S508` (snmp-insecure-version) and `S509`
(snmp-weak-cryptography) rules to support both old and new PySNMP API
module paths. Previously, these rules only detected the old API path
`pysnmp.hlapi.*`, but now they correctly detect all PySNMP API variants
including `pysnmp.hlapi.asyncio.*`, `pysnmp.hlapi.v1arch.*`,
`pysnmp.hlapi.v3arch.*`, and `pysnmp.hlapi.auth.*`.
Fixes#21364
## Problem Analysis
The `S508` and `S509` rules used exact pattern matching on qualified
names:
- `S509` only matched `["pysnmp", "hlapi", "UsmUserData"]`
- `S508` only matched `["pysnmp", "hlapi", "CommunityData"]`
This meant that newer PySNMP API paths were not detected, such as:
- `pysnmp.hlapi.asyncio.UsmUserData`
- `pysnmp.hlapi.v3arch.asyncio.UsmUserData`
- `pysnmp.hlapi.v3arch.asyncio.auth.UsmUserData`
- `pysnmp.hlapi.auth.UsmUserData`
- Similar variants for `CommunityData` in `S508`
Additionally, the old API path `pysnmp.hlapi.auth.*` was also missing
from both rules.
## Approach
Instead of exact pattern matching, both rules now check if:
1. The qualified name starts with `["pysnmp", "hlapi"]`
2. The qualified name ends with the target class name (`"UsmUserData"`
for `S509`, `"CommunityData"` for `S508`)
This flexible approach matches all PySNMP API paths without hardcoding
each variant, making the rules more maintainable and future-proof.
## Test Plan
Added comprehensive test cases to both `S508.py` and `S509.py` test
files covering:
- New API paths: `pysnmp.hlapi.asyncio.*`, `pysnmp.hlapi.v1arch.*`,
`pysnmp.hlapi.v3arch.*`
- Old API path: `pysnmp.hlapi.auth.*`
- Both insecure and secure usage patterns
All existing tests pass, and new snapshot tests were added and accepted.
Manual verification confirms both rules correctly detect all PySNMP API
variants.
---------
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
## Summary
Fixes https://github.com/astral-sh/ty/issues/1571.
I realised I was overcomplicating things when I described what we should
do in that issue description. The simplest thing to do here is just to
special-case call expressions and short-circuit the call-binding
machinery entirely if we see it's `NotImplemented` being called. It
doesn't really matter if the subdiagnostic doesn't fire when a union is
called and one element of the union is `NotImplemented` -- the
subdiagnostic doesn't need to be exhaustive; it's just to help people in
some common cases.
## Test Plan
Added snapshots
## Summary
The `.expect()` call here:
5dd56264fb/crates/ty_python_semantic/src/types/instance.rs (L816-L827)
is the direct cause of the panic in
https://github.com/astral-sh/ty/issues/1587. This patch gets rid of the
panic by refactoring our `Protocol` enum so that the
`Protocol::FromClass` variant holds a `ProtocolClass` instance rather
than a `ClassType` instance (all the `.expect()` call was doing was
attempting to convert form a `ClassType` to a `ProtocolClass`).
I hoped that this would provide a fix for
https://github.com/astral-sh/ty/issues/1587, but we still panic on the
provided reproducible examples in that issue even with this PR.
Nonetheless, I think this PR is a worthwhile change to make because:
- It's probably slightly more efficient this way (we no longer have to
re-verify that the wrapped class in a `Protocol::FromClass()` variant is
a protocol class every time we want to access its interface)
- It's nice to get rid of `.expect()` calls where possible, and this one
seems definitely unnecessary
- The _new_ panic message on this PR branch makes it much clearer what
the underlying cause of the bug in
https://github.com/astral-sh/ty/issues/1587 is:
<details>
<summary>New panic message</summary>
```
error[panic]: Panicked at
/Users/alexw/.cargo/git/checkouts/salsa-e6f3bb7c2a062968/a885bb4/src/function/execute.rs:321:21
when checking `/Users/alexw/dev/ruff/foo.py`: `ClassLiteral < 'db
>::explicit_bases_(Id(4c09)): execute: too many cycle iterations`
info: This indicates a bug in ty.
info: If you could open an issue at
https://github.com/astral-sh/ty/issues/new?title=%5Bpanic%5D, we'd be
very appreciative!
info: Platform: macos aarch64
info: Version: ruff/0.14.5+60 (18a14bfaf 2025-11-19)
info: Args: ["target/debug/ty", "check", "foo.py",
"--python-version=3.14"]
info: run with `RUST_BACKTRACE=1` environment variable to show the full
backtrace information
info: query stacktrace:
0: cached_protocol_interface(Id(6805))
at crates/ty_python_semantic/src/types/protocol_class.rs:790
1: is_equivalent_to_object_inner(Id(8003))
at crates/ty_python_semantic/src/types/instance.rs:667
2: infer_deferred_types(Id(1409))
at crates/ty_python_semantic/src/types/infer.rs:141
cycle heads: infer_definition_types(Id(140b)) -> iteration = 200,
TypeVarInstance < 'db >::lazy_bound_(Id(5803)) -> iteration = 200
3: TypeVarInstance < 'db >::lazy_bound_(Id(5802))
at crates/ty_python_semantic/src/types.rs:8734
4: infer_definition_types(Id(140c))
at crates/ty_python_semantic/src/types/infer.rs:94
5: infer_deferred_types(Id(140a))
at crates/ty_python_semantic/src/types/infer.rs:141
6: TypeVarInstance < 'db >::lazy_bound_(Id(5803))
at crates/ty_python_semantic/src/types.rs:8734
7: infer_definition_types(Id(140b))
at crates/ty_python_semantic/src/types/infer.rs:94
8: infer_scope_types(Id(1000))
at crates/ty_python_semantic/src/types/infer.rs:70
9: check_file_impl(Id(c00))
at crates/ty_project/src/lib.rs:535
Found 1 diagnostic
WARN A fatal error occurred while checking some files. Not all project
files were analyzed. See the diagnostics list above for details.
```
</details>
## Test Plan
All existing tests pass.
This patch lets us create specializations from a constraint set. The
constraint encodes the restrictions on which types each typevar can
specialize to. Given a generic context and a constraint set, we iterate
through all of the generic context's typevars. For each typevar, we
abstract the constraint set so that it only mentions the typevar in
question (propagating derived facts if needed). We then find the "best
representative type" for the typevar given the abstracted constraint
set.
When considering the BDD structure of the abstracted constraint set,
each path from the BDD root to the `true` terminal represents one way
that the constraint set can be satisfied. (This is also one of the
clauses in the DNF representation of the constraint set's boolean
formula.) Each of those paths is the conjunction of the individual
constraints of each internal node that we traverse as we walk that path,
giving a single lower/upper bound for the path. We use the upper bound
as the "best" (i.e. "closest to `object`") type for that path.
If there are multiple paths in the BDD, they technically represent
independent possible specializations. If there's a single specialization
that satisfies all of them, we will return that as the specialization.
If not, then the constraint set is ambiguous. (This happens most often
with constrained typevars.) We could in the future turn _each_ of the
paths into separate specializations, but it's not clear what we would do
with that, so instead we just report the ambiguity as a specialization
failure.
We were previously normalizing the upper and lower bounds of each
constraint when constructing constraint sets. Like in #21463, this was
for conflated reasons: It made constraint set displays nicer, since we
wouldn't render multiple constraints with obviously equivalent bounds.
(Think `T ≤ A & B` and `T ≤ B & A`) But it was also useful for
correctness, since prior to #21463 we were (trying to) add the full
transitive closure to a constraint set's BDD, and normalization gave a
useful reduction in the number of nodes in a typical BDD.
Now that we don't store the transitive closure explicitly, that second
reason is no longer relevant. Our sequent map can store that full
transitive closure much more efficiently than the expanded BDD would
have. This helps fix some false positives on #20933, where we're seeing
some (incorrect, need to be fixed, but ideally not blocking this effort)
assignability failures between a type and its normalization.
Normalization is still useful for display purposes, and so we do
normalize the upper/lower bounds before building up our display
representation of a constraint set BDD.
---------
Co-authored-by: David Peter <sharkdp@users.noreply.github.com>
We're seeing flaky test failures on macos, which seems to be caused by
different Salsa ID orderings on the different platforms. Constraint set
BDDs order their internal nodes based on the Salsa IDs of the interned
typevar structs, and we had some code that depended on variable ordering
in an unexpected way.
This patch definitely fixes the macos test failure on #21414, and
hopefully fixes it on #21436, too.
## Summary
Add a set of comprehensive tests for generic implicit type aliases to
illustrate the current behavior with many flavors of `@Todo` types and
false positive diagnostics.
The tests are partially based on the typing conformance suite, and the
expected behavior has been checked against other type checkers.
## Summary
Get rid of the catch-all todo type from subscripting a base type we
haven't implemented handling for yet in a type expression, and turn it
into a diagnostic instead.
Handle a few more cases explicitly, to avoid false positives from the
above change:
1. Subscripting any dynamic type (not just a todo type) in a type
expression should just result in that same dynamic type. This is
important for gradual guarantee, and matches other type checkers.
2. Subscripting a generic alias may be an error or not, depending
whether the specialization itself contains typevars. Don't try to handle
this yet (it should be handled in a later PR for specializing generic
non-PEP695 type aliases), just use a dedicated todo type for it.
3. Add a temporary todo branch to avoid false positives from string PEP
613 type aliases. This can be removed in the next PR, with PEP 613 type
alias support.
## Test Plan
Adjusted mdtests, ecosystem.
All new diagnostics in conformance suite are supposed to be diagnostics,
so this PR is a strict improvement there.
New diagnostics in the ecosystem are surfacing cases where we already
don't understand an annotation, but now we emit a diagnostic about it.
They are mostly intentional choices. Analysis of particular cases:
* `attrs`, `bokeh`, `django-stubs`, `dulwich`, `ibis`, `kornia`,
`mitmproxy`, `mongo-python-driver`, `mypy`, `pandas`, `poetry`,
`prefect`, `pydantic`, `pytest`, `scrapy`, `trio`, `werkzeug`, and
`xarray` are all cases where under `from __future__ import annotations`
or Python 3.14 deferred-annotations semantics, we follow normal
name-scoping rules, whereas some other type checkers prefer global names
over local names. This means we don't like it if e.g. you have a class
with a method or attribute named `type` or `tuple`, and you also try to
use `type` or `tuple` in method/attribute annotations of that class.
This PR isn't changing those semantics, just revealing them in more
cases where previously we just silently fell back to `Unknown`. I think
failing with a diagnostic (so authors can alias names as needed to avoid
relying on scoping rules that differ between type checkers) is better
than failing silently here.
* `beartype` assumes we support `TypeForm` (because it only supports
mypy and pyright, it uses `if MYPY:` to hide the `TypeForm` from mypy,
and pyright supports `TypeForm`), and we don't yet.
* `graphql-core` likes to use a `try: ... except ImportError: ...`
pattern for importing special forms from `typing` with fallback to
`typing_extensions`, instead of using `sys.version_info` checks. We
don't handle this well when type checking under an older Python version
(where the import from `typing` is not found); we see the imported name
as of type e.g. `Unknown | SpecialFormType(...)`, and because of the
union with `Unknown` we fail to handle it as the special form type. Mypy
and pyright also don't seem to support this pattern. They don't complain
about subscripting such special forms, but they do silently fail to
treat them as the desired special form. Again here, if we are going to
fail I'd rather fail with a diagnostic rather than silently.
* `ibis` is [trying to
use](https://github.com/ibis-project/ibis/blob/main/ibis/common/collections.py#L372)
`frozendict: type[FrozenDict]` as a way to create a "type alias" to
`FrozenDict`, but this is wrong: that means `frozendict:
type[FrozenDict[Any, Any]]`.
* `mypy` has some errors due to the fact that type-checking `typing.pyi`
itself (without knowing that it's the real `typing.pyi`) doesn't work
very well.
* `mypy-protobuf` imports some types from the protobufs library that end
up unioned with `Unknown` for some reason, and so we don't allow
explicit-specialization of them. Depending on the reason they end up
unioned with `Unknown`, we might want to better support this? But it's
orthogonal to this PR -- we aren't failing any worse here, just alerting
the author that we didn't understand their annotation.
* `pwndbg` has unresolved references due to star-importing from a
dependency that isn't installed, and uses un-imported names like `Dict`
in annotation expressions. Some of the unresolved references were hidden
by
https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/src/types/infer/builder.rs#L7223-L7228
when some annotations previously resolved to a Todo type that no longer
do.
Summary
--
This PR wires up the `Diagnostic::set_documentation_url` method from
#21502 to Ruff's lint diagnostics. This enables the links for the full
and concise output formats without any other changes.
I considered also including the URLs for the grouped and pylint output
formats, but the grouped format is still in `ruff_linter` instead of
`ruff_db`, so we'd have to export some additional functionality to wire
it up with `fmt_with_hyperlink`; and the pylint format doesn't currently
render with color, so I think it might actually be machine readable
rather than human readable?
The other ouput formats (json, json-lines, junit, github, gitlab,
rdjson, azure, sarif) seem more clearly not to need the links.
Test Plan
--
I guess you can't see my cursor or the browser opening, but it works for
lint rules, which have links, and doesn't include a link for syntax
errors, which don't have valid links.
Closes#11216
Essentially the approach is to implement `Format` for a new struct
`FormatClause` which is just a clause header _and_ its body. We then
have the information we need to see whether there is a skip suppression
comment on the last child in the body and it all fits on one line.
This saga began with a regression in how we handle constraint sets where
a typevar is constrained by another typevar, which #21068 first added
support for:
```py
def mutually_constrained[T, U]():
# If [T = U ∧ U ≤ int], then [T ≤ int] must be true as well.
given_int = ConstraintSet.range(U, T, U) & ConstraintSet.range(Never, U, int)
static_assert(given_int.implies_subtype_of(T, int))
```
While working on #21414, I saw a regression in this test, which was
strange, since that PR has nothing to do with this logic! The issue is
that something in that PR made us instantiate the typevars `T` and `U`
in a different order, giving them differently ordered salsa IDs. And
importantly, we use these salsa IDs to define the variable ordering that
is used in our constraint set BDDs. This showed that our "mutually
constrained" logic only worked for one of the two possible orderings.
(We can — and now do — test this in a brute-force way by copy/pasting
the test with both typevar orderings.)
The underlying bug was in our `ConstraintSet::simplify_and_domain`
method. It would correctly detect `(U ≤ T ≤ U) ∧ (U ≤ int)`, because
those two constraints affect different typevars, and from that, infer `T
≤ int`. But it wouldn't detect the equivalent pattern in `(T ≤ U ≤ T) ∧
(U ≤ int)`, since those constraints affect the same typevar. At first I
tried adding that as yet more pattern-match logic in the ever-growing
`simplify_and_domain` method. But doing so caused other tests to start
failing.
At that point, I realized that `simplify_and_domain` had gotten to the
point where it was trying to do too much, and for conflicting consumers.
It was first written as part of our display logic, where the goal is to
remove redundant information from a BDD to make its string rendering
simpler. But we also started using it to add "derived facts" to a BDD. A
derived fact is a constraint that doesn't appear in the BDD directly,
but which we can still infer to be true. Our failing test relies on
derived facts — being able to infer that `T ≤ int` even though that
particular constraint doesn't appear in the original BDD. Before,
`simplify_and_domain` would trace through all of the constraints in a
BDD, figure out the full set of derived facts, and _add those derived
facts_ to the BDD structure. This is brittle, because those derived
facts are not universally true! In our example, `T ≤ int` only holds
along the BDD paths where both `T = U` and `U ≤ int`. Other paths will
test the negations of those constraints, and on those, we _shouldn't_
infer `T ≤ int`. In theory it's possible (and we were trying) to use BDD
operators to express that dependency...but that runs afoul of how we
were simultaneously trying to _remove_ information to make our displays
simpler.
So, I ripped off the band-aid. `simplify_and_domain` is now _only_ used
for display purposes. I have not touched it at all, except to remove
some logic that is definitely not used by our `Display` impl. Otherwise,
I did not want to touch that house of cards for now, since the display
logic is not load-bearing for any type inference logic.
For all non-display callers, we have a new **_sequent map_** data type,
which tracks exactly the same derived information. But it does so (a)
without trying to remove anything from the BDD, and (b) lazily, without
updating the BDD structure.
So the end result is that all of the tests (including the new
regressions) pass, via a more efficient (and hopefully better
structured/documented) implementation, at the cost of hanging onto a
pile of display-related tech debt that we'll want to clean up at some
point.
## Summary
This is another attempt at https://github.com/astral-sh/ruff/pull/21410
that fixes https://github.com/astral-sh/ruff/issues/19226.
@MichaReiser helped me get something working in a very helpful pairing
session. I pushed one additional commit moving the comments back from
leading comments to trailing comments, which I think retains more of the
input formatting.
I was inspired by Dylan's PR (#21185) to make one of these tables:
<table>
<thead>
<tr>
<th scope="col">Input</th>
<th scope="col">Main</th>
<th scope="col">PR</th>
</tr>
</thead>
<tbody>
<tr>
<td><pre lang="python">
if (
not
# comment
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +
bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
pass
</pre></td>
<td><pre lang="python">
if (
# comment
not aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+ bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
pass
</pre></td>
<td><pre lang="python">
if (
not
# comment
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+ bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
pass
</pre></td>
</tr>
<tr>
<td><pre lang="python">
if (
# unary comment
not
# operand comment
(
# comment
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+ bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
)
):
pass
</pre></td>
<td><pre lang="python">
if (
# unary comment
# operand comment
not (
# comment
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+ bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
)
):
pass
</pre></td>
<td><pre lang="python">
if (
# unary comment
not
# operand comment
(
# comment
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+ bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
)
):
pass
</pre></td>
</tr>
<tr>
<td><pre lang="python">
if (
not # comment
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+ bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
pass
</pre></td>
<td><pre lang="python">
if ( # comment
not aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+ bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
pass
</pre></td>
<td><pre lang="python">
if (
not aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa # comment
+ bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
pass
</pre></td>
</tr>
</tbody>
</table>
hopefully it helps even though the snippets are much wider here.
The two main differences are (1) that we now retain own-line comments
between the unary operator and its operand instead of moving these to
leading comments on the operator itself, and (2) that we move
end-of-line comments between the operator and operand to dangling
end-of-line comments on the operand (the last example in the table).
## Test Plan
Existing tests, plus new ones based on the issue. As I noted below, I
also ran the output from main on the unary.py file back through this
branch to check that we don't reformat code from main. This made me feel
a bit better about not preview-gating the changes in this PR.
```shell
> git show main:crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/unary.py | ruff format - | ./target/debug/ruff format --diff -
> echo $?
0
```
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Takayuki Maeda <takoyaki0316@gmail.com>
## Summary
This PR proposes that we add a new `set_concise_message` functionality
to our `Diagnostic` construction API. When used, the concise message
that is otherwise auto-generated from the main diagnostic message and
the primary annotation will be overwritten with the custom message.
To understand why this is desirable, let's look at the `invalid-key`
diagnostic. This is how I *want* the full diagnostic to look like:
<img width="620" height="282" alt="image"
src="https://github.com/user-attachments/assets/3bf70f52-9d9f-4817-bc16-fb0ebf7c2113"
/>
However, without the change in this PR, the concise message would have
the following form:
```
error[invalid-key]: Unknown key "Age" for TypedDict `Person`: Unknown key "Age" - did you mean "age"?
```
This duplication is why the full `invalid-key` diagnostic used a main
diagnostic message that is only "Invalid key for TypedDict `Person`", to
make that bearable:
```
error[invalid-key] Invalid key for TypedDict `Person`: Unknown key "Age" - did you mean "age"?
```
This is still less than ideal, *and* we had to make the "full"
diagnostic worse. With the new API here, we have to make no such
compromises. We need to do slightly more work (provide one additional
custom-designed message), but we get to keep the "full" diagnostic that
we actually want, and we can make the concise message more terse and
readable:
```
error[invalid-key] Unknown key "Age" for TypedDict `Person` - did you mean "age"?
```
Similar problems exist for other diagnostics as well (I really want this
for https://github.com/astral-sh/ruff/pull/21476). In this PR, I only
changed `invalid-key` and `type-assertion-failure`.
The PR here is somewhat related to the discussion in
https://github.com/astral-sh/ty/issues/1418, but note that we are
solving a problem that is unrelated to sub-diagnostics.
## Test Plan
Updated tests
## Summary
Add support for `Callable` special forms in implicit type aliases.
## Typing conformance
Four new tests are passing
## Ecosystem impact
* All of the `invalid-type-form` errors are from libraries that use
`mypy_extensions` and do something like `Callable[[NamedArg("x", str)],
int]`.
* A handful of new false positives because we do not support generic
specializations of implicit type aliases, yet. But other
* Everything else looks like true positives or known limitations
## Test Plan
New Markdown tests.
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Fixes#21389
Avoid RUF012 false positives when reassigning a ClassVar
## Test Plan
<!-- How was it tested? -->
Added the new reassignment scenario to
`crates/ruff_linter/resources/test/fixtures/ruff/RUF012.py`.
---------
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
Constraint sets can now track subtyping/assignability/etc of generic
callables correctly. For instance:
```py
def identity[T](t: T) -> T:
return t
constraints = ConstraintSet.always()
static_assert(constraints.implies_subtype_of(TypeOf[identity], Callable[[int], int]))
static_assert(constraints.implies_subtype_of(TypeOf[identity], Callable[[str], str]))
```
A generic callable can be considered an intersection of all of its
possible specializations, and an assignability check with an
intersection as the lhs side succeeds of _any_ of the intersected types
satisfies the check. Put another way, if someone expects to receive any
function with a signature of `(int) -> int`, we can give them
`identity`.
Note that the corresponding check using `is_subtype_of` directly does
not yet work, since #20093 has not yet hooked up the core typing
relationship logic to use constraint sets:
```py
# These currently fail
static_assert(is_subtype_of(TypeOf[identity], Callable[[int], int]))
static_assert(is_subtype_of(TypeOf[identity], Callable[[str], str]))
```
To do this, we add a new _existential quantification_ operation on
constraint sets. This takes in a list of typevars and _removes_ those
typevars from the constraint set. Conceptually, we return a new
constraint set that evaluates to `true` when there was _any_ assignment
of the removed typevars that caused the old constraint set to evaluate
to `true`.
When comparing a generic constraint set, we add its typevars to the
`inferable` set, and figure out whatever constraints would allow any
specialization to satisfy the check. We then use the new existential
quantification operator to remove those new typevars, since the caller
doesn't (and shouldn't) know anything about them.
---------
Co-authored-by: David Peter <sharkdp@users.noreply.github.com>
Closes#19350
This fixes a syntax error caused by formatting. However, the new tests reveal that there are some cases where formatting attributes with certain comments behaves strangely, both before and after this PR, so some more polish may be in order.
For example, without parentheses around the value, and both before and after this PR, we have:
```python
# unformatted
variable = (
something # a comment
.first_method("some string")
)
# formatted
variable = something.first_method("some string") # a comment
```
which is probably not where the comment ought to go.
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Partially addresses https://github.com/astral-sh/ty/issues/1562
Only suggest the keyword "as" in import statements when the user have
written `import foo a<CURSOR>` or `from foo import bar a<CURSOR>` as no
other suggestion makes sense here.
Re-uses the existing pattern for incomplete `import from` statements to
determine incomplete import alias statements and make the suggestions
more sane in those cases.
There was a potential suggestion from @BurntSushi in
https://github.com/astral-sh/ty/issues/1562#issue-3626853513 to move the
handling of import statements into one unified state machine but I acted
on the side of caution and fixed this with already established patterns,
pending a potential bigger re-write down the line.
## Test Plan
Added new tests and checked that it behaved reasonable in the
playground.
<!-- How was it tested? -->
This PR attempts to improve the placement of own-line comments between
branches in the setting where the comment is more indented than the
preceding node.
There are two main changes.
### First change: Preceding node has leading content
If the preceding node has leading content, we now regard the comment as
automatically _less_ indented than the preceding node, and format
accordingly.
For example,
```python
if True: preceding_node
# leading on `else`, not trailing on `preceding_node`
else: ...
```
This is more compatible with `black`, although there is a (presumably
very uncommon) edge case:
```python
if True:
this;that
# leading on `else`, but trailing in `black`
else: ...
```
I'm sort of okay with this - presumably if one wanted a comment for
those semi-colon separated statements, one should have put it _above_
them, and one wanted a comment only for `that` then it ought to have
been on the same line?
### Second change: searching for last child in body
While searching for the (recursively) last child in the body of the
preceding _branch_, we implicitly assumed that the preceding node had to
have a body to begin the recursion. But actually, in the base case, the
preceding node _is_ the last child in the body of the preceding branch.
So, for example:
```python
if True:
something
last_child_but_no_body
# leading on else for `main` but trailing in this PR
else: ...
```
### More examples
The table below is an attempt to summarize the changes in behavior. The
rows alternate between an example snippet with `while` and the same
example with `if` - in the former case we do _not_ have an `else` node
and in the latter we do.
Notice that:
1. On `main` our handling of `if` vs. `while` is not consistent, whereas
it is consistent in the present PR
2. We disagree with `black` in all cases except that last example on
`main`, but agree in all cases for the present PR (though see above for
a wonky edge case where we disagree).
<table>
<tr>
<th>Original
</th>
<th><code>main</code> </th>
<th>This
PR </th>
<th><code>black</code> </th>
</tr>
<tr>
<td>
<pre lang="python">
while True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
while True:
pass
else:
# comment
pass
</pre>
</td>
<td>
<pre lang="python">
while True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
while True:
pass
# comment
else:
pass
</pre>
</td>
</tr>
<tr>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
</tr>
<tr>
<td>
<pre lang="python">
while True: pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
while True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
while True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
while True:
pass
# comment
else:
pass
</pre>
</td>
</tr>
<tr>
<td>
<pre lang="python">
if True: pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
</tr>
<tr>
<td>
<pre lang="python">
while True: pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
while True:
pass
else:
# comment
pass
</pre>
</td>
<td>
<pre lang="python">
while True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
while True:
pass
# comment
else:
pass
</pre>
</td>
</tr>
<tr>
<td>
<pre lang="python">
if True: pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
<td>
<pre lang="python">
if True:
pass
# comment
else:
pass
</pre>
</td>
</tr>
</table>
## Summary
Follow up from https://github.com/astral-sh/ruff/pull/21411. Again,
there are more things that could be improved here (like the diagnostics
for `lists`, or extending what we have for `dict` to `OrderedDict` etc),
but that will have to be postponed.
## Summary
We previously only allowed models to overwrite the
`{eq,order,kw_only,frozen}_defaults` of the dataclass-transformer, but
all other standard-dataclass parameters should be equally supported with
the same behavior.
## Test Plan
Added regression tests.
## Summary
Not a high-priority task... but it _is_ a weekend :P
This PR improves our diagnostics for invalid exceptions. Specifically:
- We now give a special-cased ``help: Did you mean
`NotImplementedError`` subdiagnostic for `except NotImplemented`, `raise
NotImplemented` and `raise <EXCEPTION> from NotImplemented`
- If the user catches a tuple of exceptions (`except (foo, bar, baz):`)
and multiple elements in the tuple are invalid, we now collect these
into a single diagnostic rather than emitting a separate diagnostic for
each tuple element
- The explanation of why the `except`/`raise` was invalid ("must be a
`BaseException` instance or `BaseException` subclass", etc.) is
relegated to a subdiagnostic. This makes the top-level diagnostic
summary much more concise.
## Test Plan
Lots of snapshots. And here's some screenshots:
<details>
<summary>Screenshots</summary>
<img width="1770" height="1520" alt="image"
src="https://github.com/user-attachments/assets/7f27fd61-c74d-4ddf-ad97-ea4fd24d06fd"
/>
<img width="1916" height="1392" alt="image"
src="https://github.com/user-attachments/assets/83e5027c-8798-48a6-a0ec-1babfc134000"
/>
<img width="1696" height="588" alt="image"
src="https://github.com/user-attachments/assets/1bc16048-6eb4-4dfa-9ace-dd271074530f"
/>
</details>
## Summary
Allow metaclass-based and baseclass-based dataclass-transformers to
overwrite the default behavior using class arguments:
```py
class Person(Model, order=True):
# ...
```
## Conformance tests
Four new tests passing!
## Test Plan
New Markdown tests
This PR updates the constraint implication type relationship to work on
compound types as well. (A compound type is a non-atomic type, like
`list[T]`.)
The goal of constraint implication is to check whether the requirements
of a constraint imply that a particular subtyping relationship holds.
Before, we were only checking atomic typevars. That would let us verify
that the constraint set `T ≤ bool` implies that `T` is always a subtype
of `int`. (In this case, the lhs of the subtyping check, `T`, is an
atomic typevar.)
But we weren't recursing into compound types, to look for nested
occurrences of typevars. That means that we weren't able to see that `T
≤ bool` implies that `Covariant[T]` is always a subtype of
`Covariant[int]`.
Doing this recursion means that we have to carry the constraint set
along with us as we recurse into types as part of `has_relation_to`, by
adding constraint implication as a new `TypeRelation` variant. (Before
it was just a method on `ConstraintSet`.)
---------
Co-authored-by: David Peter <sharkdp@users.noreply.github.com>
## Summary
Currently our diagnostic only covers the range of the thing being
subscripted:
<img width="1702" height="312" alt="image"
src="https://github.com/user-attachments/assets/7e630431-e846-46ca-93c1-139f11aaba11"
/>
But it should probably cover the _whole_ subscript expression (arguably
the more "incorrect" bit is the `["foo"]` part of this expression, not
the `x` part of this expression!)
## Test Plan
Added a snapshot
Co-authored-by: Brent Westbrook
<36778786+ntBre@users.noreply.github.com>
## Summary
Extends literal promotion to apply to any generic method, as opposed to
only generic class constructors. This PR also improves our literal
promotion heuristics to only promote literals in non-covariant position
in the return type, and avoid promotion if the literal is present in
non-covariant position in any argument type.
Resolves https://github.com/astral-sh/ty/issues/1357.
## Summary
- Always restore the previous `deferred_state` after parsing a type
expression: we don't want that state leaking out into other contexts
where we shouldn't be deferring expression inference
- Always defer the right-hand-side of a PEP-613 type alias in a stub
file, allowing for forward references on the right-hand side of `T:
TypeAlias = X | Y` in a stub file
Addresses @carljm's review in
https://github.com/astral-sh/ruff/pull/21401#discussion_r2524260153
## Test Plan
I added a regression test for a regression that the first version of
this PR introduced (we need to make sure the r.h.s. of a PEP-613
`TypeAlias`es is always deferred in a stub file)
## Summary
We currently fail to account for the type context when inferring generic
classes constructed with `__new__`, or synthesized `__init__` for
dataclasses.
There are a few places in Python where it is known that new names are
being introduced and thus we probably shouldn't offer completions. We
already handle this today for things like `class <CURSOR>` and `def
<CURSOR>`. But we didn't handle `as <CURSOR>`, which can appear in
`import`, `with`, `except` and `match` statements. Indeed, these are
exactly the 4 cases where the `as` keyword can occur. So we look for the
presence of `as` and suppress completions based on that.
While we're here, we also make the implementation a bit more robust with
respect to suppressing completions when the user hasn't typed anything.
Namely, previously, we'd still offer completions in a `class <CURSOR>`
context. But it looks like LSP clients (at least, VS Code) doesn't ask
for completions here, so we were "saved" incidentally. This PR detects
this case and suppresses completions there so we don't rely on LSP
client behavior to handle that case correctly.
Fixesastral-sh/ty#1287
## Summary
Infer the first argument `type` inside `Annotated[type, …]` as a type
expression. This allows us to support stringified annotations inside
`Annotated`.
## Ecosystem
* The removed diagnostic on `prefect` shows that we now understand the
`State.data` type annotation in
`src/prefect/client/schemas/objects.py:230`, which uses a stringified
annotation in `Annoated`. The other diagnostics are downstream changes
that result from this, it seems to be a commonly used data type.
* `artigraph` does something like `Annotated[cast(Any,
field_info.annotation), *field_info.metadata]` which I'm not sure we
need to allow? It's unfortunate since this is probably supported at
runtime, but it seems reasonable that they need to add a `# type:
ignore` for that.
* `pydantic` uses something like `Annotated[(self.annotation,
*self.metadata)]` but adds a `# type: ignore`
## Test Plan
New Markdown test
## Summary
Typeshed has a (fake) `__getattr__` method on `types.ModuleType` with a
return type of `Any`. We ignore this method when accessing attributes on
module *literals*, but with this PR, we respect this method when dealing
with `ModuleType` itself. That is, we allow arbitrary attribute accesses
on instances of `types.ModuleType`. This is useful because dynamic
import mechanisms such as `importlib.import_module` use `ModuleType` as
a return type.
closes https://github.com/astral-sh/ty/issues/1346
## Ecosystem
Massive reduction in diagnostics. The few new diagnostics are true
positives.
## Test Plan
Added regression test.
## Summary
Add synthetic members to completions on dataclasses and dataclass
instances.
Also, while we're at it, add support for `__weakref__` and
`__match_args__`.
closes https://github.com/astral-sh/ty/issues/1542
## Test Plan
New Markdown tests
## Summary
Support various legacy `typing` special forms (`List`, `Dict`, …) in
implicit type aliases.
## Ecosystem impact
A lot of true positives (e.g. on `alerta`)!
## Test Plan
New Markdown tests
## Summary
Support `type[…]` in implicit type aliases, for example:
```py
SubclassOfInt = type[int]
reveal_type(SubclassOfInt) # GenericAlias
def _(subclass_of_int: SubclassOfInt):
reveal_type(subclass_of_int) # type[int]
```
part of https://github.com/astral-sh/ty/issues/221
## Typing conformance
```diff
-specialtypes_type.py:138:5: error[type-assertion-failure] Argument does not have asserted type `type[Any]`
-specialtypes_type.py:140:5: error[type-assertion-failure] Argument does not have asserted type `type[Any]`
```
Two new tests passing ✔️
```diff
-specialtypes_type.py:146:1: error[unresolved-attribute] Object of type `GenericAlias` has no attribute `unknown`
```
An `TA4.unknown` attribute on a PEP 613 alias (`TA4: TypeAlias =
type[Any]`) is being accessed, and the conformance suite expects this to
be an error. Since we currently use the inferred type for these type
aliases (and possibly in the future as well), we treat this as a direct
access of the attribute on `type[Any]`, which falls back to an access on
`Any` itself, which succeeds. 🔴
```
+specialtypes_type.py:152:16: error[invalid-type-form] `typing.TypeVar` is not a generic class
+specialtypes_type.py:156:16: error[invalid-type-form] `typing.TypeVar` is not a generic class
```
New errors because we don't handle `T = TypeVar("T"); MyType = type[T];
MyType[T]` yet. Support for this is being tracked in
https://github.com/astral-sh/ty/issues/221🔴
## Ecosystem impact
Looks mostly good, a few known problems.
## Test Plan
New Markdown tests
## Summary
Allow users of `mdtest.py` to press enter to rerun all mdtests without
recompiling (thanks @AlexWaygood).
I swear I tried three other approaches (including a fully async version)
before I settled on this solution. It is indeed silly, but works just
fine.
## Test Plan
Interactive playing around
## Summary
Further improve subscript assignment diagnostics, especially for
`dict`s:
```py
config: dict[str, int] = {}
config["retries"] = "three"
```
<img width="1276" height="274" alt="image"
src="https://github.com/user-attachments/assets/9762c733-8d1c-4a57-8c8a-99825071dc7d"
/>
I have many more ideas, but this looks like a reasonable first step.
Thank you @AlexWaygood for some of the suggestions here.
## Test Plan
Update tests
## Summary
This change to the mdtest runner makes it easy to run on a subset of
tests/files. For example:
```
▶ uv run crates/ty_python_semantic/mdtest.py implicit
running 1 test
test mdtest__implicit_type_aliases ... ok
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 281 filtered out; finished in 0.83s
Ready to watch for changes...
```
Subsequent changes to either that test file or the Rust source code will
also only rerun the `implicit_type_aliases` test.
Multiple arguments can be provided, and filters can either be partial
file paths (`loops/for.md`, `loops/for`, `for`) or mangled test names
(`loops_for`):
```
▶ uv run crates/ty_python_semantic/mdtest.py implicit binary/union
running 2 tests
test mdtest__binary_unions ... ok
test mdtest__implicit_type_aliases ... ok
test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 280 filtered out; finished in 0.85s
Ready to watch for changes...
```
## Test Plan
Tested it interactively for a while
## Summary
This PR renames the `CallableBinding::matching_overload_index` field to
`CallableBinding::matching_overload_after_parameter_matching` to clarify
the main use case of this field which is to surface type checking errors
on the matching overloads directly instead of using the
`no-matching-overload` diagnostic. This can only happen after parameter
matching as following steps could filter out this overload which should
then result in `no-matching-overload` diagnostic.
Callers should use the `matching_overload_index` _method_ to get the
matching overloads.
## Summary
We synthesize a (potentially large) set of `__setitem__` overloads for
every item in a `TypedDict`. Previously, validation of subscript
assignments on `TypedDict`s relied on actually calling `__setitem__`
with the provided key and value types, which implied that we needed to
do the full overload call evaluation for this large set of overloads.
This PR improves the performance of subscript assignment checks on
`TypedDict`s by validating the assignment directly instead of calling
`__setitem__`.
This PR also adds better handling for assignments to subscripts on union
and intersection types (but does not attempt to make it perfect). It
achieves this by distributing the check over unions and intersections,
instead of calling `__setitem__` on the union/intersection directly. We
already do something similar when validating *attribute* assignments.
## Ecosystem impact
* A lot of diagnostics change their rule type, and/or split into
multiple diagnostics. The new version is more verbose, but easier to
understand, in my opinion
* Almost all of the invalid-key diagnostics come from pydantic, and they
should all go away (including many more) when we implement
https://github.com/astral-sh/ty/issues/1479
* Everything else looks correct to me. There may be some new diagnostics
due to the fact that we now check intersections.
## Test Plan
New Markdown tests.
## Summary
cf. https://github.com/astral-sh/ruff/pull/20962
In the following code, `foo` in the comprehension was not reported as
unresolved:
```python
# error: [unresolved-reference] "Name `foo` used when not defined"
foo
foo = [
# no error!
# revealed: Divergent
reveal_type(x) for _ in () for x in [foo]
]
baz = [
# error: [unresolved-reference] "Name `baz` used when not defined"
# revealed: Unknown
reveal_type(x) for _ in () for x in [baz]
]
```
In fact, this is a more serious bug than it looks: for `foo`,
[`explicit_global_symbol` is
called](6cc3393ccd/crates/ty_python_semantic/src/types/infer/builder.rs (L8052)),
causing a symbol that should actually be `Undefined` to be reported as
being of type `Divergent`.
This PR fixes this bug. As a result, the code in
`mdtest/regression/pr_20962_comprehension_panics.md` no longer panics.
## Test Plan
`corpus\cyclic_symbol_in_comprehension.py` is added.
New tests are added in `mdtest/comprehensions/basic.md`.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Fixes#21393
Now the rule checks if the index variable is initialized as an `int`
type rather than only flagging if the index variable is initialized to
`0`. I used `ResolvedPythonType` to check if the index variable is an
`int` type.
## Test Plan
Updated snapshot test for `SIM113`.
---------
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
## Summary
Add (snapshot) tests for subscript assignment diagnostics. This is
mainly intended to establish a baseline before I hope to improve some of
these messages.
## Summary
Add support for `typing.Union` in implicit type aliases / in value
position.
## Typing conformance tests
Two new tests are passing
## Ecosystem impact
* The 2k new `invalid-key` diagnostics on pydantic are caused by
https://github.com/astral-sh/ty/issues/1479#issuecomment-3513854645.
* Everything else I've checked is either a known limitation (often
related to type narrowing, because union types are often narrowed down
to a subset of options), or a true positive.
## Test Plan
New Markdown tests
I don't know why, but it always takes me an eternity to find the failing
project name a few lines below in the output. So I'm suggesting we just
add the project name to the assertion message.
## Summary
Fix https://github.com/astral-sh/ty/issues/664
This PR adds support for storing attributes in comprehension scopes (any
eager scope.)
For example in the following code we infer type of `z` correctly:
```py
class C:
def __init__(self):
[None for self.z in range(1)]
reveal_type(C().z) # previously [unresolved-attribute] but now shows Unknown | int
```
The fix works by adjusting the following logics:
To identify if an attriute is an assignment to self or cls we need to
check the scope is a method. To allow comprehension scopes here we skip
any eager scope in the check.
Also at this stage the code checks if self or the first method argument
is shadowed by another binding that eager scope to prevent this:
```py
class D:
g: int
class C:
def __init__(self):
[[None for self.g in range(1)] for self in [D()]]
reveal_type(C().g) # [unresolved-attribute]
```
When determining scopes that attributes might be defined after
collecting all the methods of the class the code also returns any
decendant scope that is eager and only has eager parents until the
method scope.
When checking reachability of a attribute definition if the attribute is
defined in an eager scope we use the reachability of the first non eager
scope which must be a method. This allows attributes to be marked as
reachable and be seen.
There are also which I didn't add support for:
```py
class C:
def __init__(self):
def f():
[None for self.z in range(1)]
f()
reveal_type(C().z) # [unresolved-attribute]
```
In the above example we will not even return the comprehension scope as
an attribute scope because there is a non eager scope (`f` function)
between the comprehension and the `__init__` method
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
It looks like VS Code does this forcefully. As in, I don't think we can
override it. It also seems like a plausibly good idea. But by us doing
it too, it makes our completion evaluation framework match real world
conditions. (To the extent that "VS Code" and "real world conditions"
are the same. Which... they aren't. But it's close, since VS Code is so
popular.)
This should round out the rest of the set. I think I had hesitated doing
this before because some of these don't make sense in every context. But
I think identifying the correct context for every keyword could be quite
difficult. And at the very least, I think offering these at least as a
choice---even if they aren't always correct---is better than not doing
it at all.
## Summary
Fixes https://github.com/astral-sh/ty/issues/1409
This PR allows `Final` instance attributes to be initialized in
`__init__` methods, as mandated by the Python typing specification (PEP
591). Previously, ty incorrectly prevented this initialization, causing
false positive errors.
The fix checks if we're inside an `__init__` method before rejecting
Final attribute assignments, allowing assignments during
instance initialization while still preventing reassignment elsewhere.
## Test Plan
- Added new test coverage in `final.md` for the reported issue with
`Self` annotations
- Updated existing tests that were incorrectly expecting errors
- All 278 mdtest tests pass
- Manually tested with real-world code examples
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Fixes https://github.com/astral-sh/ty/issues/1487
This one is a true extension of non-standard semantics, and is therefore
a certified Hot Take we might conclude is simply a Bad Take (let's see
what ecosystem tests say...).
By resolving `.` and the LHS of the from import during semantic
indexing, we can check if the LHS is a submodule of `.`, and handle
`from whatever.thispackage.x.y import z` exactly like we do `from .x.y
import z`.
Fixes https://github.com/astral-sh/ty/issues/1484
This manifested as an error when inferring the type of a PEP-695 generic
class via its constructor parameters:
```py
class D[T, U]:
@overload
def __init__(self: "D[str, U]", u: U) -> None: ...
@overload
def __init__(self, t: T, u: U) -> None: ...
def __init__(self, *args) -> None: ...
# revealed: D[Unknown, str]
# SHOULD BE: D[str, str]
reveal_type(D("string"))
```
This manifested because `D` is inferred to be bivariant in both `T` and
`U`. We weren't seeing this in the equivalent example for legacy
typevars, since those default to invariant. (This issue also showed up
for _covariant_ typevars, so this issue was not limited to bivariance.)
The underlying cause was because of a heuristic that we have in our
current constraint solver, which attempts to handle situations like
this:
```py
def f[T](t: T | None): ...
f(None)
```
Here, the `None` argument matches the non-typevar union element, so this
argument should not add any constraints on what `T` can specialize to.
Our previous heuristic would check for this by seeing if the argument
type is a subtype of the parameter annotation as a whole — even if it
isn't a union! That would cause us to erroneously ignore the `self`
parameter in our constructor call, since bivariant classes are
equivalent to each other, regardless of their specializations.
The quick fix is to move this heuristic "down a level", so that we only
apply it when the parameter annotation is a union. This heuristic should
go away completely 🤞 with the new constraint solver.
This loses any ability to have "per-function" implicit submodule
imports, to avoid the "ok but now we need per-scope imports" and "ok but
this should actually introduce a global that only exists during this
function" problems. A simple and clean implementation with no weird
corners.
Fixes https://github.com/astral-sh/ty/issues/1482
This rips out the previous implementation in favour of a new
implementation with 3 rules:
- **froms are locals**: a `from..import` can only define locals, it does
not have global
side-effects. Specifically any submodule attribute `a` that's implicitly
introduced by either
`from .a import b` or `from . import a as b` (in an `__init__.py(i)`) is
a local and not a
global. If you do such an import at the top of a file you won't notice
this. However if you do
such an import in a function, that means it will only be function-scoped
(so you'll need to do
it in every function that wants to access it, making your code less
sensitive to execution
order).
- **first from first serve**: only the *first* `from..import` in an
`__init__.py(i)` that imports a
particular direct submodule of the current package introduces that
submodule as a local.
Subsequent imports of the submodule will not introduce that local. This
reflects the fact that
in actual python only the first import of a submodule (in the entire
execution of the program)
introduces it as an attribute of the package. By "first" we mean "the
first time in this scope
(or any parent scope)". This pairs well with the fact that we are
specifically introducing a
local (as long as you don't accidentally shadow or overwrite the local).
- **dot re-exports**: `from . import a` in an `__init__.pyi` is
considered a re-export of `a`
(equivalent to `from . import a as a`). This is required to properly
handle many stubs in the
wild. Currently it must be *exactly* `from . import ...`.
This implementation is intentionally limited/conservative (notably,
often requiring a from import to be relative). I'm going to file a ton
of followups for improvements so that their impact can be evaluated
separately.
Fixes https://github.com/astral-sh/ty/issues/133
## Summary
Fixed RUF065 (`logging-eager-conversion`) to only flag `str()` calls
when they perform a simple conversion that can be safely removed. The
rule now ignores `str()` calls with no arguments, multiple arguments,
starred arguments, or keyword unpacking, preventing false positives.
Fixes#21315
## Problem Analysis
The RUF065 rule was incorrectly flagging all `str()` calls in logging
statements, even when `str()` was performing actual conversion work
beyond simple type coercion. Specifically, the rule flagged:
- `str()` with no arguments - which returns an empty string
- `str(b"data", "utf-8")` with multiple arguments - which performs
encoding conversion
- `str(*args)` with starred arguments - which unpacks arguments
- `str(**kwargs)` with keyword unpacking - which passes keyword
arguments
These cases cannot be safely removed because `str()` is doing meaningful
work (encoding conversion, argument unpacking, etc.), not just redundant
type conversion.
The root cause was that the rule only checked if the function was
`str()` without validating the call signature. It didn't distinguish
between simple `str(value)` conversions (which can be removed) and more
complex `str()` calls that perform actual work.
## Approach
The fix adds validation to the `str()` detection logic in
`logging_eager_conversion.rs`:
1. **Check argument count**: Only flag `str()` calls with exactly one
positional argument (`str_call_args.args.len() == 1`)
2. **Check for starred arguments**: Ensure the single argument is not
starred (`!str_call_args.args[0].is_starred_expr()`)
3. **Check for keyword arguments**: Ensure there are no keyword
arguments (`str_call_args.keywords.is_empty()`)
This ensures the rule only flags cases like `str(value)` where `str()`
is truly redundant and can be removed, while ignoring cases where
`str()` performs actual conversion work.
The fix maintains backward compatibility - all existing valid test cases
continue to be flagged correctly, while the new edge cases are properly
ignored.
---------
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
It's everyone's favourite language corner case!
Also having kicked the tires on it, I'm pretty happy to call this (in
conjunction with #21367):
Fixes https://github.com/astral-sh/ty/issues/494
There's cases where you can make noisy Literal hints appear, so we can
always iterate on it, but this handles like, 98% of the cases in the
wild, which is great.
---------
Co-authored-by: David Peter <sharkdp@users.noreply.github.com>
I'm not 100% sold on this implementation, but it's a strict improvement
and it adds a ton of snapshot tests for future iteration.
Part of https://github.com/astral-sh/ty/issues/494
## Summary
Fixes FURB105 (`print-empty-string`) to detect empty f-strings in
addition to regular empty strings. Previously, the rule only flagged
`print("")` but missed `print(f"")`. This fix ensures both cases are
detected and can be automatically fixed.
Fixes#21346
## Problem Analysis
The FURB105 rule checks for unnecessary empty strings passed to
`print()` calls. The `is_empty_string` helper function was only checking
for `Expr::StringLiteral` with empty values, but did not handle
`Expr::FString` (f-strings). As a result, `print(f"")` was not being
flagged as a violation, even though it's semantically equivalent to
`print("")` and should be simplified to `print()`.
The issue occurred because the function used a `matches!` macro that
only checked for string literals:
```rust
fn is_empty_string(expr: &Expr) -> bool {
matches!(
expr,
Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) if value.is_empty()
)
}
```
## Approach
1. **Import the helper function**: Added `is_empty_f_string` to the
imports from `ruff_python_ast::helpers`, which already provides logic to
detect empty f-strings.
2. **Update `is_empty_string` function**: Changed the implementation
from a `matches!` macro to a `match` expression that handles both string
literals and f-strings:
```rust
fn is_empty_string(expr: &Expr) -> bool {
match expr {
Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) =>
value.is_empty(),
Expr::FString(f_string) => is_empty_f_string(f_string),
_ => false,
}
}
```
The fix leverages the existing `is_empty_f_string` helper function which
properly handles the complexity of f-strings, including nested f-strings
and interpolated expressions. This ensures the detection is accurate and
consistent with how empty strings are detected elsewhere in the
codebase.
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## Summary
Resolves https://github.com/astral-sh/ty/issues/1494
## Test Plan
Add a test showing if we are in `from <name> <name> ` we provide the
keyword completion "import"
This elides the following inlay hints:
```py
foo([x=]x)
foo([x=]y.x)
foo([x=]x[0])
foo([x=]x(...))
# composes to complex situations
foo([x=]y.x(..)[0])
```
Fixes https://github.com/astral-sh/ty/issues/1514
Summary
--
Fixes#21360 by using the union of names instead of overwriting them, as
Micha suggested originally on #21104.
This avoids overwriting the `n` name in the `Subscript` by the empty set
of names visited in the nested OR pattern before visiting the other arm
of the outer OR pattern.
Test Plan
--
A new inline test case taken from the issue
## Summary
Detect usages of implicit `self` in property getters, which allows us to
treat their signature as being generic.
closes https://github.com/astral-sh/ty/issues/1502
## Typing conformance
Two new type assertions that are succeeding.
## Ecosystem results
Mostly look good. There are a few new false positives related to a bug
with constrained typevars that is unrelated to the work here. I reported
this as https://github.com/astral-sh/ty/issues/1503.
## Test Plan
Added regression tests.
## Summary
Add support for `Optional` and `Annotated` in implicit type aliases
part of https://github.com/astral-sh/ty/issues/221
## Typing conformance changes
New expected diagnostics.
## Ecosystem
A lot of true positives, some known limitations unrelated to this PR.
## Test Plan
New Markdown tests
## Summary
This PR adds extra validation for `isinstance()` and `issubclass()`
calls that use `UnionType` instances for their second argument.
According to typeshed's annotations, any `UnionType` is accepted for the
second argument, but this isn't true at runtime: at runtime, all
elements in the `UnionType` must either be class objects or be `None` in
order for the `isinstance()` or `issubclass()` call to reliably succeed:
```pycon
% uvx python3.14
Python 3.14.0 (main, Oct 10 2025, 12:54:13) [Clang 20.1.4 ] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from typing import LiteralString
>>> import types
>>> type(LiteralString | int) is types.UnionType
True
>>> isinstance(42, LiteralString | int)
Traceback (most recent call last):
File "<python-input-5>", line 1, in <module>
isinstance(42, LiteralString | int)
~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/alexw/Library/Application Support/uv/python/cpython-3.14.0-macos-aarch64-none/lib/python3.14/typing.py", line 559, in __instancecheck__
raise TypeError(f"{self} cannot be used with isinstance()")
TypeError: typing.LiteralString cannot be used with isinstance()
```
## Test Plan
Added mdtests/snapshots
## Summary
Fixed FURB101 (`read-whole-file`) to handle annotated assignments.
Previously, the rule would detect violations in code like `contents: str
= f.read()` but fail to generate a fix. Now it correctly generates fixes
that preserve type annotations (e.g., `contents: str =
Path("file.txt").read_text(encoding="utf-8")`).
Fixes#21274
## Problem Analysis
The FURB101 rule was only checking for `Stmt::Assign` statements when
determining whether a fix could be applied. When encountering annotated
assignments (`Stmt::AnnAssign`) like `contents: str = f.read()`, the
rule would:
1. Correctly detect the violation (the diagnostic was reported)
2. Fail to generate a fix because:
- The `visit_expr` method only matched `Stmt::Assign`, not
`Stmt::AnnAssign`
- The `generate_fix` function only accepted `Stmt::Assign` in its body
validation
- The replacement code generation didn't account for type annotations
This occurred because Python's AST represents annotated assignments as a
different node type (`StmtAnnAssign`) with separate fields for the
target, annotation, and value, unlike regular assignments which use a
list of targets.
## Approach
The fix extends the rule to handle both assignment types:
1. **Updated `visit_expr` method**: Now matches both `Stmt::Assign` and
`Stmt::AnnAssign`, extracting:
- Variable name from the target expression
- Type annotation code (when present) using the code generator
2. **Updated `generate_fix` function**:
- Added `annotation: Option<String>` parameter to accept annotation code
- Updated body validation to accept both `Stmt::Assign` and
`Stmt::AnnAssign`
- Modified replacement code generation to preserve annotations: `{var}:
{annotation} = {binding}({filename_code}).{suggestion}`
3. **Added test case**: Added an annotated assignment test case to
verify the fix works correctly.
The implementation maintains backward compatibility with regular
assignments while adding support for annotated assignments, ensuring
type annotations are preserved in the generated fixes.
---------
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
We have lots of `TypeVisitor`s that end up having very similar
`visit_type` implementations. This PR consolidates some of the code for
these so that there's less repetition and duplication.
When checking whether a constraint set is satisfied, if a typevar has a
non-fully-static upper bound or constraint, we are free to choose any
materialization that makes the check succeed.
In non-inferable positions, we have to show that the constraint set is
satisfied for all valid specializations, so it's best to choose the most
restrictive materialization, since that minimizes the set of valid
specializations that have to pass.
In inferable positions, we only have to show that the constraint set is
satisfied for _some_ valid specializations, so it's best to choose the
most permissive materialization, since that maximizes our chances of
finding a specialization that passes.
Summary
--
These rules are themselves in preview, so we don't need the additional
preview checks on the fixes or the separate preview tests. This has
confused me in a couple of reviews of changes to the fixes.
Test Plan
--
Existing tests, with the fixes previously only shown in the preview
tests now in the "non-preview" tests.
## Summary
Add support for `Literal` types in implicit type aliases.
part of https://github.com/astral-sh/ty/issues/221
## Ecosystem analysis
This looks good to me, true positives and known problems.
## Test Plan
New Markdown tests.
## Summary
This PR adds support for understanding the legacy definition and PEP 695
definition for `ParamSpec`.
This is still very initial and doesn't really implement any of the
semantics.
Part of https://github.com/astral-sh/ty/issues/157
## Test Plan
Add mdtest cases.
## Ecosystem analysis
Most of the diagnostics in `starlette` are due to the fact that ty now
understands `ParamSpec` is not a `Todo` type, so the assignability check
fails. The code looks something like:
```py
class _MiddlewareFactory(Protocol[P]):
def __call__(self, app: ASGIApp, /, *args: P.args, **kwargs: P.kwargs) -> ASGIApp: ... # pragma: no cover
class Middleware:
def __init__(
self,
cls: _MiddlewareFactory[P],
*args: P.args,
**kwargs: P.kwargs,
) -> None:
self.cls = cls
self.args = args
self.kwargs = kwargs
# ty complains that `ServerErrorMiddleware` is not assignable to `_MiddlewareFactory[P]`
Middleware(ServerErrorMiddleware, handler=error_handler, debug=debug)
```
There are multiple diagnostics where there's an attribute access on the
`Wrapped` object of `functools` which Pyright also raises:
```py
from functools import wraps
def my_decorator(f):
@wraps(f)
def wrapper(*args, **kwds):
return f(*args, **kwds)
# Pyright: Cannot access attribute "__signature__" for class "_Wrapped[..., Unknown, ..., Unknown]"
Attribute "__signature__" is unknown [reportAttributeAccessIssue]
# ty: Object of type `_Wrapped[Unknown, Unknown, Unknown, Unknown]` has no attribute `__signature__` [unresolved-attribute]
wrapper.__signature__
return wrapper
```
There are additional diagnostics that is due to the assignability checks
failing because ty now infers the `ParamSpec` instead of using the
`Todo` type which would always succeed. This results in a few
`no-matching-overload` diagnostics because the assignability checks
fail.
There are a few diagnostics related to
https://github.com/astral-sh/ty/issues/491 where there's a variable
which is either a bound method or a variable that's annotated with
`Callable` that doesn't contain the instance as the first parameter.
Another set of (valid) diagnostics are where the code hasn't provided
all the type variables. ty is now raising diagnostics for these because
we include `ParamSpec` type variable in the signature. For example,
`staticmethod[Any]` which contains two type variables.
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Closes https://github.com/astral-sh/ty/issues/989
There are various situations where users expect the Python packages
installed in the same environment as ty itself to be considered during
type checking. A minimal example would look like:
```
uv venv my-env
uv pip install my-env ty httpx
echo "import httpx" > foo.py
./my-env/bin/ty check foo.py
```
or
```
uv tool install ty --with httpx
echo "import httpx" > foo.py
ty check foo.py
```
While these are a bit contrived, there are real-world situations where a
user would expect a similar behavior to work. Notably, all of the other
type checkers consider their own environment when determining search
paths (though I'll admit that I have not verified when they choose not
to do this).
One common situation where users are encountering this today is with
`uvx --with-requirements script.py ty check script.py` — which is
currently our "best" recommendation for type checking a PEP 723 script,
but it doesn't work.
Of the options discussed in
https://github.com/astral-sh/ty/issues/989#issuecomment-3307417985, I've
chosen (2) as our criteria for including ty's environment in the search
paths.
- If no virtual environment is discovered, we will always include ty's
environment.
- If a `.venv` is discovered in the working directory, we will _prepend_
ty's environment to the search paths. The dependencies in ty's
environment (e.g., from `uvx --with`) will take precedence.
- If a virtual environment is active, e.g., `VIRTUAL_ENV` (i.e.,
including conda prefixes) is set, we will not include ty's environment.
The reason we need to special case the `.venv` case is that we both
1. Recommend `uvx ty` today as a way to check your project
2. Want to enable `uvx --with <...> ty`
And I don't want (2) to break when you _happen_ to be in a project
(i.e., if we only included ty's environment when _no_ environment is
found) and don't want to remove support for (1).
I think long-term, I want to make `uvx <cmd>` layer the environment on
_top_ of the project environment (in uv), which would obviate the need
for this change when you're using uv. However, that change is breaking
and I think users will expect this behavior in contexts where they're
not using uv, so I think we should handle it in ty regardless.
I've opted not to include the environment if it's non-virtual (i.e., a
system environment) for now. It seems better to start by being more
restrictive. I left a comment in the code.
## Test Plan
I did some manual testing with the initial commit, then subsequently
added some unit tests.
```
❯ echo "import httpx" > example.py
❯ uvx --with httpx ty check example.py
Installed 8 packages in 19ms
error[unresolved-import]: Cannot resolve imported module `httpx`
--> foo/example.py:1:8
|
1 | import httpx
| ^^^^^
|
info: Searched in the following paths during module resolution:
info: 1. /Users/zb/workspace/ty/python (first-party code)
info: 2. /Users/zb/workspace/ty (first-party code)
info: 3. vendored://stdlib (stdlib typeshed stubs vendored by ty)
info: make sure your Python environment is properly configured: https://docs.astral.sh/ty/modules/#python-environment
info: rule `unresolved-import` is enabled by default
Found 1 diagnostic
❯ uvx --from . --with httpx ty check example.py
All checks passed!
```
```
❯ uv init --script foo.py
Initialized script at `foo.py`
❯ uv add --script foo.py httpx
warning: The Python request from `.python-version` resolved to Python 3.13.8, which is incompatible with the script's Python requirement: `>=3.14`
Updated `foo.py`
❯ echo "import httpx" >> foo.py
❯ uvx --with-requirements foo.py ty check foo.py
error[unresolved-import]: Cannot resolve imported module `httpx`
--> foo.py:15:8
|
13 | if __name__ == "__main__":
14 | main()
15 | import httpx
| ^^^^^
|
info: Searched in the following paths during module resolution:
info: 1. /Users/zb/workspace/ty/python (first-party code)
info: 2. /Users/zb/workspace/ty (first-party code)
info: 3. vendored://stdlib (stdlib typeshed stubs vendored by ty)
info: make sure your Python environment is properly configured: https://docs.astral.sh/ty/modules/#python-environment
info: rule `unresolved-import` is enabled by default
Found 1 diagnostic
❯ uvx --from . --with-requirements foo.py ty check foo.py
All checks passed!
```
Notice we do not include ty's environment if `VIRTUAL_ENV` is set
```
❯ VIRTUAL_ENV=.venv uvx --with httpx ty check foo/example.py
error[unresolved-import]: Cannot resolve imported module `httpx`
--> foo/example.py:1:8
|
1 | import httpx
| ^^^^^
|
info: Searched in the following paths during module resolution:
info: 1. /Users/zb/workspace/ty/python (first-party code)
info: 2. /Users/zb/workspace/ty (first-party code)
info: 3. vendored://stdlib (stdlib typeshed stubs vendored by ty)
info: 4. /Users/zb/workspace/ty/.venv/lib/python3.13/site-packages (site-packages)
info: make sure your Python environment is properly configured: https://docs.astral.sh/ty/modules/#python-environment
info: rule `unresolved-import` is enabled by default
Found 1 diagnostic
```
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## Summary
Raised by @AlexWaygood.
We previously did not favour imported symbols, when we probably
should've
## Test Plan
Add test showing that we favour imported symbol even if it is
alphabetically after other symbols that are builtin.
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
This PR ports PLE0117 as a semantic syntax error.
## Test Plan
<!-- How was it tested? -->
Tests previously written
---------
Signed-off-by: 11happy <soni5happy@gmail.com>
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
This PR carries over some of the `has_relation_to` logic for comparing a
typevar with itself. A typevar will specialize to the same type if it's
mentioned multiple times, so it is always assignable to and a subtype of
itself. (Note that typevars can only specialize to fully static types.)
This is also true when the typevar appears in a union on the right-hand
side, or in an intersection on the left-hand side. Similarly, a typevar
is always disjoint from its negation, so when a negated typevar appears
on the left-hand side, the constraint set is never satisfiable.
(Eventually this will allow us to remove the corresponding clauses from
`has_relation_to`, but that can't happen until more of #20093 lands.)
## Summary
Splitting this one out from https://github.com/astral-sh/ruff/pull/21210. This is also something that should be made obselete by the new constraint solver, but is easy enough to fix now.
## Summary
Fixes FURB157 false negative where `Decimal("_-1")` was not flagged as
verbose when underscores precede the sign character. This fixes#21186.
## Problem Analysis
The `verbose-decimal-constructor` (FURB157) rule failed to detect
verbose `Decimal` constructors when the sign character (`+` or `-`) was
preceded by underscores. For example, `Decimal("_-1")` was not flagged,
even though it can be simplified to `Decimal(-1)`.
The bug occurred because the rule checked for the sign character at the
start of the string before stripping leading underscores. According to
Python's `Decimal` parser behavior (as documented in CPython's
`_pydecimal.py`), underscores are removed before parsing the sign. The
rule's logic didn't match this behavior, causing a false negative for
cases like `"_-1"` where the underscore came before the sign.
This was a regression introduced in version 0.14.3, as these cases were
correctly flagged in version 0.14.2.
## Approach
The fix updates the sign extraction logic to:
1. Strip leading underscores first (matching Python's Decimal parser
behavior)
2. Extract the sign from the underscore-stripped string
3. Preserve the string after the sign for normalization purposes
This ensures that cases like `Decimal("_-1")`, `Decimal("_+1")`, and
`Decimal("_-1_000")` are correctly detected and flagged. The
normalization logic was also updated to use the string after the sign
(without underscores) to avoid double signs in the replacement output.
## Summary
Allow values of type `None` in type expressions. The [typing
spec](https://typing.python.org/en/latest/spec/annotations.html#type-and-annotation-expressions)
could be more explicit on whether this is actually allowed or not, but
it seems relatively harmless and does help in some use cases like:
```py
try:
from module import MyClass
except ImportError:
MyClass = None # ty: ignore
def f(m: MyClass):
pass
```
## Test Plan
Updated tests, ecosystem check.
Summary
--
This PR fixes#17796 by taking the approach mentioned in
https://github.com/astral-sh/ruff/issues/17796#issuecomment-2847943862
of simply recursing into the `MatchAs` patterns when checking if we need
parentheses. This allows us to reuse the parentheses in the inner
pattern before also breaking the `MatchAs` pattern itself:
```diff
match class_pattern:
case Class(xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx) as capture:
pass
- case (
- Class(xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx) as capture
- ):
+ case Class(
+ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+ ) as capture:
pass
- case (
- Class(
- xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
- ) as capture
- ):
+ case Class(
+ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+ ) as capture:
pass
case (
Class(
@@ -685,13 +683,11 @@
match sequence_pattern_brackets:
case [xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx] as capture:
pass
- case (
- [xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx] as capture
- ):
+ case [
+ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+ ] as capture:
pass
- case (
- [
- xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
- ] as capture
- ):
+ case [
+ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+ ] as capture:
pass
```
I haven't really resolved the question of whether or not it's okay
always to recurse, but I'm hoping the ecosystem check on this PR might
shed some light on that.
Test Plan
--
New tests based on the issue and then reviewing the ecosystem check here
## Summary
A lot of the bidirectional inference work relies on `dict` not being
assignable to `TypedDict`, so I think it makes sense to add this before
fully implementing https://github.com/astral-sh/ty/issues/1387.
## Summary
Add support for implicit type aliases that use PEP 604 unions:
```py
IntOrStr = int | str
reveal_type(IntOrStr) # UnionType
def _(int_or_str: IntOrStr):
reveal_type(int_or_str) # int | str
```
## Typing conformance
The changes are either removed false positives, or new diagnostics due
to known limitations unrelated to this PR.
## Ecosystem impact
Spot checked, a mix of true positives and known limitations.
## Test Plan
New Markdown tests.
Fixes https://github.com/astral-sh/ty/issues/1053
## Summary
Other type checkers prioritize a submodule over a package `__getattr__`
in `from mod import sub`, even though the runtime precedence is the
other direction. In effect, this is making an implicit assumption that a
module `__getattr__` will not handle (that is, will raise
`AttributeError`) for names that are also actual submodules, rather than
shadowing them. In practice this seems like a realistic assumption in
the ecosystem? Or at least the ecosystem has adapted to it, and we need
to adapt this precedence also, for ecosystem compatibility.
The implementation is a bit ugly, precisely because it departs from the
runtime semantics, and our implementation is oriented toward modeling
runtime semantics accurately. That is, `__getattr__` is modeled within
the member-lookup code, so it's hard to split "member lookup result from
module `__getattr__`" apart from other member lookup results. I did this
via a synthetic `TypeQualifier::FROM_MODULE_GETATTR` that we attach to a
type resulting from a member lookup, which isn't beautiful but it works
well and doesn't introduce inefficiency (e.g. redundant member lookups).
## Test Plan
Updated mdtests.
Also added a related mdtest formalizing our support for a module
`__getattr__` that is explicitly annotated to accept a limited set of
names. In principle this could be an alternative (more explicit) way to
handle the precedence problem without departing from runtime semantics,
if the ecosystem would adopt it.
### Ecosystem analysis
Lots of removed diagnostics which are an improvement because we now
infer the expected submodule.
Added diagnostics are mostly unrelated issues surfaced now because we
previously had an earlier attribute error resulting in `Unknown`; now we
correctly resolve the module so that earlier attribute error goes away,
we get an actual type instead of `Unknown`, and that triggers a new
error.
In scipy and sklearn, the module `__getattr__` which we were respecting
previously is un-annotated so returned a forgiving `Unknown`; now we
correctly see the actual module, which reveals some cases of
https://github.com/astral-sh/ty/issues/133 that were previously hidden
(`scipy/optimize/__init__.py` [imports `from
._tnc`](eff82ca575/scipy/optimize/__init__.py (L429)).)
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
* extend AIR301 to include deprecated argument `concurrency` in
`airflow....DAG`
## Test Plan
<!-- How was it tested? -->
update the existing test fixture in the first commit and then reorganize
in the second one
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## Summary
Resolves https://github.com/astral-sh/ty/issues/1464
We sort the completions before we add the unimported ones, meaning that
imported completions show up before unimported ones.
This is also spoken about in
https://github.com/astral-sh/ty/issues/1274, and this is probably a
duplicate of that.
@AlexWaygood mentions this
[here](https://github.com/astral-sh/ty/issues/1274#issuecomment-3345942698)
too.
## Test Plan
Add a test showing even if an unimported completion "should"
(alphabetically before) come first, we favor the imported one.
Summary
--
This code has been unused since #14233 but not detected by clippy I
guess. This should help to remove the temptation to use the set
comparison again like I suggested in #21144. And we shouldn't do the set
comparison because of #13802, which #14233 fixed.
Test Plan
--
Existing tests
Fixes https://github.com/astral-sh/ty/issues/1368
## Summary
Add support for patterns like this, where a type alias to a literal type
(or union of literal types) is used to subscript `typing.Literal`:
```py
type MyAlias = Literal[1]
def _(x: Literal[MyAlias]): ...
```
This shows up in the ecosystem report for PEP 613 type alias support.
One interesting case is an alias to `bool` or an enum type. `bool` is an
equivalent type to `Literal[True, False]`, which is a union of literal
types. Similarly an enum type `E` is also equivalent to a union of its
member literal types. Since (for explicit type aliases) we infer the RHS
directly as a type expression, this makes it difficult for us to
distinguish between `bool` and `Literal[True, False]`, so we allow
either one to (or an alias to either one) to appear inside `Literal`,
where other type checkers allow only the latter.
I think for implicit type aliases it may be simpler to support only
types derived from actually subscripting `typing.Literal`, though, so I
didn't make a TODO-comment commitment here.
## Test Plan
Added mdtests, including TODO-filled tests for PEP 613 and implicit type
aliases.
### Conformance suite
All changes here are positive -- we now emit errors on lines that should
be errors. This is a side effect of the new implementation, not the
primary purpose of this PR, but it's still a positive change.
### Ecosystem
Eliminates one ecosystem false positive, where a PEP 695 type alias for
a union of literal types is used to subscript `typing.Literal`.
## Summary
Adds type inference for list/dict/set comprehensions, including
bidirectional inference:
```py
reveal_type({k: v for k, v in [("a", 1), ("b", 2)]}) # dict[Unknown | str, Unknown | int]
squares: list[int | None] = [x for x in range(10)]
reveal_type(squares) # list[int | None]
```
## Ecosystem impact
I did spot check the changes and most of them seem like known
limitations or true positives. Without proper bidirectional inference,
we saw a lot of false positives.
## Test Plan
New Markdown tests
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## Summary
@BurntSushi provided some feedback in #21146 so i address it here.
Summary
--
This is a first step toward fixing #9745. After reviewing our open
issues and several Black issues and PRs, I personally found the function
case the most compelling, especially with very long argument lists:
```py
def func(
self,
arg1: int,
arg2: bool,
arg3: bool,
arg4: float,
arg5: bool,
) -> tuple[...]:
if arg2 and arg3:
raise ValueError
```
or many annotations:
```py
def function(
self, data: torch.Tensor | tuple[torch.Tensor, ...], other_argument: int
) -> torch.Tensor | tuple[torch.Tensor, ...]:
do_something(data)
return something
```
I think docstrings help the situation substantially both because syntax
highlighting will usually give a very clear separation between the
annotations and the docstring and because we already allow a blank line
_after_ the docstring:
```py
def function(
self, data: torch.Tensor | tuple[torch.Tensor, ...], other_argument: int
) -> torch.Tensor | tuple[torch.Tensor, ...]:
"""
A function doing something.
And a longer description of the things it does.
"""
do_something(data)
return something
```
There are still other comments on #9745, such as [this one] with 9
upvotes, where users specifically request blank lines in all block
types, or at least including conditionals and loops. I'm sympathetic to
that case as well, even if personally I don't find an [example] like
this:
```py
if blah:
# Do some stuff that is logically related
data = get_data()
# Do some different stuff that is logically related
results = calculate_results()
return results
```
to be much more readable than:
```py
if blah:
# Do some stuff that is logically related
data = get_data()
# Do some different stuff that is logically related
results = calculate_results()
return results
```
I'm probably just used to the latter from the formatters I've used, but
I do prefer it. I also think that functions are the least susceptible to
the accidental introduction of a newline after refactoring described in
Micha's [comment] on #8893.
I actually considered further restricting this change to functions with
multiline headers. I don't think very short functions like:
```py
def foo():
return 1
```
benefit nearly as much from the allowed newline, but I just went with
any function without a docstring for now. I guess a marginal case like:
```py
def foo(a_long_parameter: ALongType, b_long_parameter: BLongType) -> CLongType:
return 1
```
might be a good argument for not restricting it.
I caused a couple of syntax errors before adding special handling for
the ellipsis-only case, so I suspect that there are some other
interesting edge cases that may need to be handled better.
Test Plan
--
Existing tests, plus a few simple new ones. As noted above, I suspect
that we may need a few more for edge cases I haven't considered.
[this one]:
https://github.com/astral-sh/ruff/issues/9745#issuecomment-2876771400
[example]:
https://github.com/psf/black/issues/902#issuecomment-1562154809
[comment]:
https://github.com/astral-sh/ruff/issues/8893#issuecomment-1867259744
## Summary
Discussion with @ibraheemdev clarified that
https://github.com/astral-sh/ruff/pull/21168 was incorrect. In a case of
failed inference of a dict literal as a `TypedDict`, we should store the
context-less inferred type of the dict literal as the type of the dict
literal expression itself; the fallback to declared type should happen
at the level of the overall assignment definition.
The reason the latter isn't working yet is because currently we
(wrongly) consider a homogeneous dict type as assignable to a
`TypedDict`, so we don't actually consider the assignment itself as
failed. So the "bug" I observed (and tried to fix) will naturally be
fixed by implementing TypedDict assignability rules.
Rollback https://github.com/astral-sh/ruff/pull/21168 except for the
tests, and modify the tests to include TODOs as needed.
## Test Plan
Updated mdtests.
The parser currently uses single quotes to wrap tokens. This is
inconsistent with the rest of ruff/ty, which use backticks.
For example, see the inconsistent diagnostics produced in this simple
example: https://play.ty.dev/0a9d6eab-6599-4a1d-8e40-032091f7f50f
Consistently wrapping tokens in backticks produces uniform diagnostics.
Following the style decision of #723, in #2889 some quotes were already
switched into backticks.
This is also in line with Rust's guide on diagnostics
(https://rustc-dev-guide.rust-lang.org/diagnostics.html#diagnostic-structure):
> When code or an identifier must appear in a message or label, it
should be surrounded with backticks
## Summary
In general, when we have an invalid assignment (inferred assigned type
is not assignable to declared type), we fall back to inferring the
declared type, since the declared type is a more explicit declaration of
the programmer's intent. This also maintains the invariant that our
inferred type for a name is always assignable to the declared type for
that same name. For example:
```py
x: str = 1
reveal_type(x) # revealed: str
```
We weren't following this pattern for dictionary literals inferred (via
type context) as a typed dictionary; if the literal was not valid for
the annotated TypedDict type, we would just fall back to the normal
inferred type of the dict literal, effectively ignoring the annotation,
and resulting in inferred type not assignable to declared type.
## Test Plan
Added mdtest assertions.
## Summary
The solver is currently order-dependent, and will choose a supertype
over the exact type if it appears earlier in the list of constraints. We
could be smarter and try to choose the most precise subtype, but I
imagine this is something the new constraint solver will fix anyways,
and this fixes the issue showing up on
https://github.com/astral-sh/ruff/pull/21070.
This PR adds a new `satisfied_by_all_typevar` method, which implements
one of the final steps of actually using these dang constraint sets.
Constraint sets exist to help us check assignability and subtyping of
types in the presence of typevars. We construct a constraint set
describing the conditions under which assignability holds between the
two types. Then we check whether that constraint set is satisfied for
the valid specializations of the relevant typevars (which is this new
method).
We also add a new `ty_extensions.ConstraintSet` method so that we can
test this method's behavior in mdtests, before hooking it up to the rest
of the specialization inference machinery.
## Summary
We currently perform a subtyping check instead of the intended subclass
check (and the subtyping check is confusingly named `is_subclass_of`).
This showed up in https://github.com/astral-sh/ruff/pull/21070.
## Summary
Before this PR, we would emit diagnostics like "Invalid key access" for
a TypedDict literal with invalid key, which doesn't make sense since
there's no "access" in that case. This PR just adjusts the wording to be
more general, and adjusts the documentation of the lint rule too.
I noticed this in the playground and thought it would be a quick fix. As
usual, it turned out to be a bit more subtle than I expected, but for
now I chose to punt on the complexity. We may ultimately want to have
different rules for invalid subscript vs invalid TypedDict literal,
because an invalid key in a TypedDict literal is low severity: it's a
typo detector, but not actually a type error. But then there's another
wrinkle there: if the TypedDict is `closed=True`, then it _is_ a type
error. So would we want to separate the open and closed cases into
separate rules, too? I decided to leave this as a question for future.
If we wanted to use separate rules, or use specific wording for each
case instead of the generalized wording I chose here, that would also
involve a bit of extra work to distinguish the cases, since we use a
generic set of functions for reporting these errors.
## Test Plan
Added and updated mdtests.
This is a second take at the implicit imports approach, allowing `from .
import submodule` in an `__init__.pyi` to create the
`mypackage.submodule` attribute everyhere.
This implementation operates inside of the
available_submodule_attributes subsystem instead of as a re-export rule.
The upside of this is we are no longer purely syntactic, and absolute
from imports that happen to target submodules work (an intentional
discussed deviation from pyright which demands a relative from import).
Also we don't re-export functions or classes.
The downside(?) of this is star imports no longer see these attributes
(this may be either good or bad. I believe it's not a huge lift to make
it work with star imports but it's some non-trivial reworking).
I've also intentionally made `import mypackage.submodule` not trigger
this rule although it's trivial to change that.
I've tried to cover as many relevant cases as possible for discussion in
the new test file I've added (there are some random overlaps with
existing tests but trying to add them piecemeal felt confusing and
weird, so I just made a dedicated file for this extension to the rules).
Fixes https://github.com/astral-sh/ty/issues/133
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
<!-- How was it tested? -->
## Summary
Fixes https://github.com/astral-sh/ty/issues/1427
This PR fixes a regression introduced in alpha.24 where non-dataclass
children of generic dataclasses lost generic type parameter information
during `__init__` synthesis.
The issue occurred because when looking up inherited members in the MRO,
the child class's `inherited_generic_context` was correctly passed down,
but `own_synthesized_member()` (which synthesizes dataclass `__init__`
methods) didn't accept this parameter. It only used
`self.inherited_generic_context(db)`, which returned the parent's
context instead of the child's.
The fix threads the child's generic context through to the synthesis
logic, allowing proper generic type inference for inherited dataclass
constructors.
## Test Plan
- Added regression test for non-dataclass inheriting from generic
dataclass
- Verified the exact repro case from the issue now works
- All 277 mdtest tests passing
- Clippy clean
- Manually verified with Python runtime, mypy, and pyright - all accept
this code pattern
## Verification
Tested against multiple type checkers:
- ✅ Python runtime: Code works correctly
- ✅ mypy: No issues found
- ✅ pyright: 0 errors, 0 warnings
- ✅ ty alpha.23: Worked (before regression)
- ❌ ty alpha.24: Regression
- ✅ ty with this fix: Works correctly
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: David Peter <mail@david-peter.de>
It's possible for a constraint to mention two typevars. For instance, in
the body of
```py
def f[S: int, T: S](): ...
```
the baseline constraint set would be `(T ≤ S) ∧ (S ≤ int)`. That is, `S`
must specialize to some subtype of `int`, and `T` must specialize to a
subtype of the type that `S` specializes to.
This PR updates the new "constraint implication" relationship from
#21010 to work on these kinds of constraint sets. For instance, in the
example above, we should be able to see that `T ≤ int` must always hold:
```py
def f[S, T]():
constraints = ConstraintSet.range(Never, S, int) & ConstraintSet.range(Never, T, S)
static_assert(constraints.implies_subtype_of(T, int)) # now succeeds!
```
This did not require major changes to the implementation of
`implies_subtype_of`. That method already relies on how our `simplify`
and `domain` methods expand a constraint set to include the transitive
closure of the constraints that it mentions, and to mark certain
combinations of constraints as impossible. Previously, that transitive
closure logic only looked at pairs of constraints that constrain the
same typevar. (For instance, to notice that `(T ≤ bool) ∧ ¬(T ≤ int)` is
impossible.)
Now we also look at pairs of constraints that constraint different
typevars, if one of the constraints is bound by the other — that is,
pairs of the form `T ≤ S` and `S ≤ something`, or `S ≤ T` and `something
≤ S`. In those cases, transitivity lets us add a new derived constraint
that `T ≤ something` or `something ≤ T`, respectively. Having done that,
our existing `implies_subtype_of` logic finds and takes into account
that derived constraint.
Summary
--
Fixes#21121 by upgrading `RuntimeEvaluated` annotations like
`dataclasses.KW_ONLY` to `RuntimeRequired`. We already had special
handling for
`TypingOnly` annotations in this context but not `RuntimeEvaluated`.
Combining
that with the `future-annotations` setting, which allowed ignoring the
`RuntimeEvaluated` flag, led to the reported bug where we would try to
move
`KW_ONLY` into a `TYPE_CHECKING` block.
Test Plan
--
A new test based on the issue
## Summary
We weren't correctly modeling it as a `staticmethod` in all cases,
leading us to incorrectly infer that the `cls` argument would be bound
if it was accessed on an instance (rather than the class object).
## Test Plan
Added mdtests that fail on `main`. The primer output also looks good!
## Summary
Fixes#21101 by storing the child visitor's names in the parent visitor.
This makes sure that `visitor.names` on line 1818 isn't empty after we
visit a nested OR pattern.
## Test Plan
New inline test cases derived from the issue,
[playground](https://play.ruff.rs/7b6439ac-ee8f-4593-9a3e-c2aa34a595d0)
## Summary
Adds proper type narrowing and reachability analysis for matching on
non-inferable type variables bound to enums. For example:
```py
from enum import Enum
class Answer(Enum):
NO = 0
YES = 1
def is_yes(self) -> bool: # no error here!
match self:
case Answer.YES:
return True
case Answer.NO:
return False
```
closes https://github.com/astral-sh/ty/issues/1404
## Test Plan
Added regression tests
## Summary
We previously didn't understand `range` and wrote these custom
`IntIterable`/`IntIterator` classes for tests. We can now remove them
and make the tests shorter in some places.
## Summary
Infer a type of unannotated `self` parameters in decorated methods /
properties.
closes https://github.com/astral-sh/ty/issues/1448
## Test Plan
Existing tests, some new tests.
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## Summary
Fixed the incorrect import example in the "correct exmaple"
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## Test Plan
🤷
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