## Summary
Tracked structs have some issues with fixpoint iteration in Salsa, and
there's not actually any need for this to be tracked, it should be
interned like most of our type structs.
The removed comment was probably never correct (in that we could have
disambiguated sufficiently), and is definitely not relevant now that
`TypeVarInstance` also holds its `Definition`.
## Test Plan
Existing tests.
## Summary
This PR adds special-casing for `@final` and `@override` decorator for a
similar reason as https://github.com/astral-sh/ruff/pull/17591 to
support the invalid overload check.
Both `final` and `override` are identity functions which can be removed
once `TypeVar` support is added.
## Summary
As promised, this just adds a TODO comment to document something we
discussed today that should probably be improved at some point, but
isn't a priority right now (since it's an issue that in practice would
only affect generic classes with both `__init__` and `__new__` methods,
where some typevar is bound to `Unknown` in one and to some other type
in another.)
## Summary
While adding semantic error support to red-knot, I noticed duplicate
diagnostics for code like this:
```py
# error: [invalid-syntax] "cannot use an asynchronous comprehension outside of an asynchronous function on Python 3.9 (syntax was added in 3.11)"
# error: [invalid-syntax] "`asynchronous comprehension` outside of an asynchronous function"
[reveal_type(x) async for x in AsyncIterable()]
```
Beyond the duplication, the first error message doesn't make much sense
because this syntax is _not_ allowed on Python 3.11 either.
To fix this, this PR renames the
`async-comprehension-outside-async-function` semantic syntax error to
`async-comprehension-in-sync-comprehension` and fixes the rule to avoid
applying outside of sync comprehensions at all.
## Test Plan
New linter test demonstrating the false positive. The mdtests from my red-knot
PR also reflect this change.
## Summary
This PR updates the `to_overloaded` method to use an iterative approach
instead of a recursive one.
Refer to
https://github.com/astral-sh/ruff/pull/17585#discussion_r2056804587 for
context.
The main benefit here is that it avoids calling the `to_overloaded`
function in a recursive manner which is a salsa query. So, this is a bit
hand wavy but we should also see less memory used because the cache will
only contain a single entry which should be the entire overload chain.
Previously, the recursive approach would mean that each of the function
involved in an overload chain would have a cache entry. This reduce in
memory shouldn't be too much and I haven't looked at the actual data for
it.
## Test Plan
Existing test cases should pass.
This mostly only improves things for incorrect arguments and for an
incorrect return type. It doesn't do much to improve the case where
`__bool__` isn't callable and leaves the union/other cases untouched
completely.
I picked this one because, at first glance, this _looked_ like a lower
hanging fruit. The conceptual improvement here is pretty
straight-forward: add annotations for relevant data. But it took me a
bit to figure out how to connect all of the pieces.
I wanted to use this method in other places, so I moved it
to what appears to be a God-type. I also made it slightly
more versatile: callers can ask for the entire parameter list
by omitting a specific parameter index.
## Summary
Historically we have avoided narrowing on `==` tests because in many
cases it's unsound, since subclasses of a type could compare equal to
who-knows-what. But there are a lot of types (literals and unions of
them, as well as some known instances like `None` -- single-valued
types) whose `__eq__` behavior we know, and which we can safely narrow
away based on equality comparisons.
This PR implements equality narrowing in the cases where it is sound.
The most elegant way to do this (and the way that is most in-line with
our approach up until now) would be to introduce new Type variants
`NeverEqualTo[...]` and `AlwaysEqualTo[...]`, and then implement all
type relations for those variants, narrow by intersection, and let union
and intersection simplification sort it all out. This is analogous to
our existing handling for `AlwaysFalse` and `AlwaysTrue`.
But I'm reluctant to add new `Type` variants for this, mostly because
they could end up un-simplified in some types and make types even more
complex. So let's try this approach, where we handle more of the
narrowing logic as a special case.
## Test Plan
Updated and added tests.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Carl Meyer <carl@oddbird.net>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Another follow-up to the unions-of-large-literals optimization. Restore
the behavior that e.g. `Literal[""] | ~Literal[""]` collapses to
`object`.
## Test Plan
Added mdtests.
## Summary
This is required because otherwise the inferred type is not going to be
`Type::FunctionLiteral` but a todo type because we don't recognize
`TypeVar` yet:
```py
_FuncT = TypeVar("_FuncT", bound=Callable[..., Any])
def abstractmethod(funcobj: _FuncT) -> _FuncT: ...
```
This is mainly required to raise diagnostic when only some (and not all)
`@overload`-ed functions are decorated with `@abstractmethod`.
## Summary
This PR adds a new method `FunctionType::to_overloaded` which converts a
`FunctionType` into an `OverloadedFunction` which contains all the
`@overload`-ed `FunctionType` and the implementation `FunctionType` if
it exists.
There's a big caveat here (it's the way overloads work) which is that
this method can only "see" all the overloads that comes _before_ itself.
Consider the following example:
```py
from typing import overload
@overload
def foo() -> None: ...
@overload
def foo(x: int) -> int: ...
def foo(x: int | None) -> int | None:
return x
```
Here, when the `to_overloaded` method is invoked on the
1. first `foo` definition, it would only contain a single overload which
is itself and no implementation.
2. second `foo` definition, it would contain both overloads and still no
implementation
3. third `foo` definition, it would contain both overloads and the
implementation which is itself
### Usages
This method will be used in the logic for checking invalid overload
usages. It can also be used for #17541.
## Test Plan
Make sure that existing tests pass.
## Summary
This is a first step toward `global` support in red-knot (#15385). I
went through all the matches for `global` in the `mypy/test-data`
directory, but I didn't find anything too interesting that wasn't
already covered by @carljm's suggestions on Discord. I still pulled in a
couple of cases for a little extra variety. I also included a section
from the
[PLE0118](https://docs.astral.sh/ruff/rules/load-before-global-declaration/)
tests in ruff that will become syntax errors once #17463 is merged and
we handle `global` statements.
I don't think I figured out how to use `@Todo` properly, so please let
me know if I need to fix that. I hope this is a good start to the test
suite otherwise.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
We now handle generic constructor methods on generic classes correctly:
```py
class C[T]:
def __init__[S](self, t: T, s: S): ...
x = C(1, "str")
```
Here, constructing `C` requires us to infer a specialization for the
generic contexts of `C` and `__init__` at the same time.
At first I thought I would need to track the full stack of nested
generic contexts here (since the `[S]` context is nested within the
`[T]` context). But I think this is the only way that we might need to
specialize more than one generic context at once — in all other cases, a
containing generic context must be specialized before we get to a nested
one, and so we can just special-case this.
While we're here, we also construct the generic context for a generic
function lazily, when its signature is accessed, instead of eagerly when
inferring the function body.
## Summary
Model assignability of class instances with a `__call__` method to
`Callable` types. This should solve some false positives related to
`functools.partial` (yes, 1098 fewer diagnostics!).
Reference:
https://github.com/astral-sh/ruff/issues/17343#issuecomment-2824618483
## Test Plan
New Markdown tests.
## Summary
Many symbols in typeshed are defined without being declared. For
example:
```pyi
# builtins:
IOError = OSError
# types
LambdaType = FunctionType
NotImplementedType = _NotImplementedType
# typing
Text = str
# random
uniform = _inst.uniform
# optparse
make_option = Option
# all over the place:
_T = TypeVar("_T")
```
Here, we introduce a change that skips widening the public type of these
symbols (by unioning with `Unknown`).
fixes#17032
## Ecosystem analysis
This is difficult to analyze in detail, but I went over most changes and
it looks very favorable to me overall. The diff on the overall numbers
is:
```
errors: 1287 -> 859 (reduction by 428)
warnings: 45 -> 59 (increase by 14)
```
### Removed false positives
`invalid-base` examples:
```diff
- error[lint:invalid-base] /tmp/mypy_primer/projects/pip/src/pip/_vendor/rich/console.py:548:27: Invalid class base with type `Unknown | Literal[_local]` (all bases must be a class, `Any`, `Unknown` or `Todo`)
- error[lint:invalid-base] /tmp/mypy_primer/projects/tornado/tornado/iostream.py:84:25: Invalid class base with type `Unknown | Literal[OSError]` (all bases must be a class, `Any`, `Unknown` or `Todo`)
- error[lint:invalid-base] /tmp/mypy_primer/projects/mitmproxy/test/conftest.py:35:40: Invalid class base with type `Unknown | Literal[_UnixDefaultEventLoopPolicy]` (all bases must be a class, `Any`, `Unknown` or `Todo`)
```
`invalid-exception-caught` examples:
```diff
- error[lint:invalid-exception-caught] /tmp/mypy_primer/projects/cloud-init/cloudinit/cmd/status.py:334:16: Cannot catch object of type `Literal[ProcessExecutionError]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)
- error[lint:invalid-exception-caught] /tmp/mypy_primer/projects/jinja/src/jinja2/loaders.py:537:16: Cannot catch object of type `Literal[TemplateNotFound]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)
```
`unresolved-reference` examples
7a0265d36e/cloudinit/handlers/jinja_template.py (L120-L123)
(we now understand the `isinstance` narrowing)
```diff
- error[lint:unresolved-attribute] /tmp/mypy_primer/projects/cloud-init/cloudinit/handlers/jinja_template.py:123:16: Type `Exception` has no attribute `errno`
```
`unknown-argument` examples
https://github.com/hauntsaninja/boostedblob/blob/master/boostedblob/request.py#L53
```diff
- error[lint:unknown-argument] /tmp/mypy_primer/projects/boostedblob/boostedblob/request.py:53:17: Argument `connect` does not match any known parameter of bound method `__init__`
```
`unknown-argument`
There are a lot of `__init__`-related changes because we now understand
[`@attr.s`](3d42a6978a/src/attr/__init__.pyi (L387))
as a `@dataclass_transform` annotated symbol. For example:
```diff
- error[lint:unknown-argument] /tmp/mypy_primer/projects/attrs/tests/test_hooks.py:72:18: Argument `x` does not match any known parameter of bound method `__init__`
```
### New false positives
This can happen if a symbol that previously was inferred as `X |
Unknown` was assigned-to, but we don't yet understand the assignability
to `X`:
https://github.com/strawberry-graphql/strawberry/blob/main/strawberry/exceptions/handler.py#L90
```diff
+ error[lint:invalid-assignment] /tmp/mypy_primer/projects/strawberry/strawberry/exceptions/handler.py:90:9: Object of type `def strawberry_threading_exception_handler(args: tuple[type[BaseException], BaseException | None, TracebackType | None, Thread | None]) -> None` is not assignable to attribute `excepthook` of type `(_ExceptHookArgs, /) -> Any`
```
### New true positives
6bbb5519fe/tests/tracer/test_span.py (L714)
```diff
+ error[lint:invalid-argument-type] /tmp/mypy_primer/projects/dd-trace-py/tests/tracer/test_span.py:714:33: Argument to this function is incorrect: Expected `str`, found `Literal[b"\xf0\x9f\xa4\x94"]`
```
### Changed diagnostics
A lot of changed diagnostics because we now show `@Todo(Support for
`typing.TypeVar` instances in type expressions)` instead of `Unknown`
for all kinds of symbols that used a `_T = TypeVar("_T")` as a type. One
prominent example is the `list.__getitem__` method:
`builtins.pyi`:
```pyi
_T = TypeVar("_T") # previously `TypeVar | Unknown`, now just `TypeVar`
# …
class list(MutableSequence[_T]):
# …
@overload
def __getitem__(self, i: SupportsIndex, /) -> _T: ...
# …
```
which causes this change in diagnostics:
```py
xs = [1, 2]
reveal_type(xs[0]) # previously `Unknown`, now `@Todo(Support for `typing.TypeVar` instances in type expressions)`
```
## Test Plan
Updated Markdown tests
Summary
--
This PR extends semantic syntax error detection to red-knot. The main
changes here are:
1. Adding `SemanticSyntaxChecker` and `Vec<SemanticSyntaxError>` fields
to the `SemanticIndexBuilder`
2. Calling `SemanticSyntaxChecker::visit_stmt` and `visit_expr` in the
`SemanticIndexBuilder`'s `visit_stmt` and `visit_expr` methods
3. Implementing `SemanticSyntaxContext` for `SemanticIndexBuilder`
4. Adding new mdtests to test the context implementation and show
diagnostics
(3) is definitely the trickiest and required (I think) a minor addition
to the `SemanticIndexBuilder`. I tried to look around for existing code
performing the necessary checks, but I definitely could have missed
something or misused the existing code even when I found it.
There's still one TODO around `global` statement handling. I don't think
there's an existing way to look this up, but I'm happy to work on that
here or in a separate PR. This currently only affects detection of one
error (`LoadBeforeGlobalDeclaration` or
[PLE0118](https://docs.astral.sh/ruff/rules/load-before-global-declaration/)
in ruff), so it's not too big of a problem even if we leave the TODO.
Test Plan
--
New mdtests, as well as new errors for existing mdtests
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Allow (instances of) subclasses of `Any` and `Unknown` to be assignable
to (instances of) other classes, unless they are final. This allows us
to get rid of ~1000 false positives, mostly when mock-objects like
`unittest.mock.MagicMock` are assigned to various targets.
## Test Plan
Adapted and new Markdown tests.
## Summary
mypy_primer changes included here:
ebaa9fd27b..4c22d192a4
- Add strawberry as a `good.txt` project (was previously included in our
fork)
- Print Red Knot compilation errors to stderr (thanks @MichaReiser)
## Summary
We currently emit a diagnostic for code like the following:
```py
from typing import Any
# error: Invalid class base with type `GenericAlias` (all bases must be a class, `Any`, `Unknown` or `Todo`)
class C(tuple[Any, ...]): ...
```
The changeset here silences this diagnostic by recognizing instances of
`GenericAlias` in `ClassBase::try_from_type`, and inferring a `@Todo`
type for them. This is a change in preparation for #17557, because `C`
previously had `Unknown` in its MRO …
```py
reveal_type(C.__mro__) # tuple[Literal[C], Unknown, Literal[object]]
```
… which would cause us to think that `C` is assignable to everything.
The changeset also removes some false positive `invalid-base`
diagnostics across the ecosystem.
## Test Plan
Updated Markdown tests.
## Summary
Add parentheses to multi-element intersections, when displayed in a
context that's otherwise potentially ambiguous.
## Test Plan
Update mdtest files
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
#17451 was incomplete. `AlwaysFalsy` and `AlwaysTruthy` are not the only
two types that are super-types of some literals (of a given kind) and
not others. That set also includes intersections containing
`AlwaysTruthy` or `AlwaysFalsy`, and intersections containing literal
types of the same kind. Cover these cases as well.
Fixes#17478.
## Test Plan
Added mdtests.
`QUICKCHECK_TESTS=1000000 cargo test -p red_knot_python_semantic --
--ignored types::property_tests::stable` failed on both
`all_fully_static_type_pairs_are_subtypes_of_their_union` and
`all_type_pairs_are_assignable_to_their_union` prior to this PR, passes
after it.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
I gave up trying to do this one lint at a time and just (mostly)
mechanically translated this entire file in one go.
Generally the messages stay the same (with most moving from an
annotation message to the diagnostic's main message). I added a couple
of `info` sub-diagnostics where it seemed to be the obvious intent.
This finishes the migration for the `INVALID_ASSIGNMENT` lint.
Notice how I'm steadily losing steam in terms of actually improving the
diagnostics. This change is more mechanical, because taking the time to
revamp every diagnostic is a ton of effort. Probably future migrations
will be similar unless there are easy pickings.
We mostly keep things the same here, but the message has been moved from
the annotation to the diagnostic's top-line message. I think this is
perhaps a little worse, but some bigger improvements could be made here.
Indeed, we could perhaps even add a "fix" here.
This moves all INVALID_ASSIGNMENT lints related to unpacking over to the new
diagnostic model.
While we're here, we improve the diagnostic a bit by adding a secondary
annotation covering where the value is. We also split apart the original
singular message into one message for the diagnostic and the "expected
versus got" into annotation messages.
This tests the diagnostic rendering of a case that wasn't previously
covered by snapshots: when unpacking fails because there are too few
values, but where the left hand side can tolerate "N or more." In the
code, this is a distinct diagnostic, so we capture it here.
(Sorry about the diff here, but it made sense to rename the other
sections and that changes the name of the snapshot file.)
I believe this was an artifact of an older iteration of the diagnostic
reporting API. But this is strictly not necessary now, and indeed, might
even be annoying. It is okay, but perhaps looks a little odd, to do
`builder.into_diagnostic("...")` if you don't want to add anything else
to the diagnostic.
I suspect this will be used pretty frequently (I wanted it
immediately). And more practically, this avoids needing to
import `Annotation` to create it.
Carl Meyer
Dhruv Manilawala
Brent Westbrook
Andrew Gallant
Matthew Mckee
Alex Waygood
Douglas Creager
David Peter
Micha Reiser