Commit graph

362 commits

Author SHA1 Message Date
David Peter
af988bf866
[red-knot] Detect division-by-zero in unions and intersections (#17157)
## Summary

With this PR, we emit a diagnostic for this case where
previously didn't:
```py
from typing import Literal

def f(m: int, n: Literal[-1, 0, 1]):
    # error: [division-by-zero] "Cannot divide object of type `int` by zero"
    return m / n
```

## Test Plan

New Markdown test
2025-04-02 18:21:27 +02:00
cake-monotone
7e97910704
[red-knot] Fix _NotImplementedType check for Python >=3.10 (#17143)
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## Summary

from https://github.com/astral-sh/ruff/pull/17034#discussion_r2024222525

This is a simple PR to fix the invalid behavior of `NotImplemented` on
Python >=3.10.


## Test Plan

I think it would be better if we could run mdtest across multiple Python
versions in GitHub Actions.

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

---------

Co-authored-by: David Peter <sharkdp@users.noreply.github.com>
2025-04-02 10:02:59 +00:00
David Peter
ae2cf91a36
[red-knot] Decorators and properties (#17017)
## Summary

Add support for decorators on function as well as support
for properties by adding special handling for `@property` and `@<name of
property>.setter`/`.getter` decorators.

closes https://github.com/astral-sh/ruff/issues/16987

## Ecosystem results

- ✔️ A lot of false positives are fixed by our new
understanding of properties
- 🔴 A bunch of new false positives (typically
`possibly-unbound-attribute` or `invalid-argument-type`) occur because
we currently do not perform type narrowing on attributes. And with the
new understanding of properties, this becomes even more relevant. In
many cases, the narrowing occurs through an assertion, so this is also
something that we need to implement to get rid of these false positives.
- 🔴 A few new false positives occur because we do not
understand generics, and therefore some calls to custom setters fail.
- 🔴 Similarly, some false positives occur because we do not
understand protocols yet.
- ✔️ Seems like a true positive to me. [The
setter](e624d8edfa/src/packaging/specifiers.py (L752-L754))
only accepts `bools`, but `None` is assigned in [this
line](e624d8edfa/tests/test_specifiers.py (L688)).
  ```
+ error[lint:invalid-assignment]
/tmp/mypy_primer/projects/packaging/tests/test_specifiers.py:688:9:
Invalid assignment to data descriptor attribute `prereleases` on type
`SpecifierSet` with custom `__set__` method
  ```
- ✔️ This is arguable also a true positive. The setter
[here](0c6c75644f/rich/table.py (L359-L363))
returns `Table`, but typeshed wants [setters to return
`None`](bf8d2a9912/stdlib/builtins.pyi (L1298)).
  ```
+ error[lint:invalid-argument-type]
/tmp/mypy_primer/projects/rich/rich/table.py:359:5: Object of type
`Literal[padding]` cannot be assigned to parameter 2 (`fset`) of bound
method `setter`; expected type `(Any, Any, /) -> None`
  ```  

## Follow ups

- Fix the `@no_type_check` regression
- Implement class decorators

## Test Plan

New Markdown test suites for decorators and properties.
2025-04-02 09:27:46 +02:00
Dhruv Manilawala
f63024843c
[red-knot] Move tuple containing Never tests (#17137)
Refer
https://github.com/astral-sh/ruff/pull/17094#discussion_r2023682840
2025-04-02 02:46:18 +00:00
Matthew Mckee
eb3e176309
[red-knot] Add callable subtyping for callable instances and bound methods (#17105)
## Summary

Trying to improve #17005
Partially fixes #16953

## Test Plan

Update is_subtype_of.md

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-04-01 23:40:44 +00:00
Dhruv Manilawala
6be0a5057d
[red-knot] Disjointness for callable types (#17094)
## Summary

Part of #15382, this PR adds support for disjointness between two
callable types. They are never disjoint because there exists a callable
type that's a subtype of all other callable types:
```py
(*args: object, **kwargs: object) -> Never
```

The `Never` is a subtype of every fully static type thus a callable type
that has the return type of `Never` means that it is a subtype of every
return type.

## Test Plan

Add test cases related to mixed parameter kinds, gradual form (`...`)
and `Never` type.
2025-04-01 19:00:27 +00:00
Alex Waygood
d6dcc377f7
[red-knot] Flatten Type::Callable into four Type variants (#17126)
## Summary

Currently our `Type::Callable` wraps a four-variant `CallableType` enum.
But as time has gone on, I think we've found that the four variants in
`CallableType` are really more different to each other than they are
similar to each other:
- `GeneralCallableType` is a structural type describing all callable
types with a certain signature, but the other three types are "literal
types", more similar to the `FunctionLiteral` variant
- `GeneralCallableType` is not a singleton or a single-valued type, but
the other three are all single-valued types
(`WrapperDescriptorDunderGet` is even a singleton type)
- `GeneralCallableType` has (or should have) ambiguous truthiness, but
all possible inhabitants of the other three types are always truthy.
- As a structural type, `GeneralCallableType` can contain inner unions
and intersections that must be sorted in some contexts in our internal
model, but this is not true for the other three variants.

This PR flattens `Type::Callable` into four distinct `Type::` variants.
In the process, it fixes a number of latent bugs that were concealed by
the current architecture but are laid bare by the refactor. Unit tests
for these bugs are included in the PR.
2025-04-01 19:30:06 +01:00
Dhruv Manilawala
d29d4956de
[red-knot] Fix callable subtyping for standard parameters (#17125)
## Summary

This PR fixes a bug in callable subtyping to consider both the
positional and keyword form of the standard parameter in the supertype
when matching against variadic, keyword-only and keyword-variadic
parameter in the subtype.

This is done by collecting the unmatched standard parameters and then
checking them against the keyword-only / keyword-variadic parameters
after the positional loop.

## Test Plan

Add test cases.
2025-04-01 23:37:35 +05:30
Alex Waygood
c74ba00219
[red-knot] Fix more redundant-cast false positives (#17119)
## Summary

There are quite a few places we infer `Todo` types currently, and some
of them are nested somewhat deeply in type expressions. These can cause
spurious issues for the new `redundant-cast` diagnostics. We fixed all
the false positives we saw in the mypy_primer report before merging
https://github.com/astral-sh/ruff/pull/17100, but I think there are
still lots of places where we'd emit false positives due to this check
-- we currently don't run on that many projects at all in our
mypy_primer check:


d0c8eaa092/.github/workflows/mypy_primer.yaml (L71)

This PR fixes some more false positives from this diagnostic by making
the `Type::contains_todo()` method more expansive.

## Test Plan

I added a regression test which causes us to emit a spurious diagnostic
on `main`, but does not with this PR.
2025-04-01 19:03:42 +01:00
Alex Waygood
49c25993eb
[red-knot] Don't infer Todo for quite so many tuple type expressions (#17116)
## Summary

I noticed we were inferring `Todo` as the declared type for annotations
such as `x: tuple[list[int], list[int]]`. This PR reworks our annotation
parsing so that we instead infer `tuple[Todo, Todo]` for this
annotation, which is quite a bit more precise.

## Test Plan

Existing mdtest updated.
2025-04-01 15:44:02 +01:00
Trevor Manz
53cfaaebc4
[red-knot] Add redundant-cast error (#17100)
## Summary

Following up from earlier discussion on Discord, this PR adds logic to
flag casts as redundant when the inferred type of the expression is the
same as the target type. It should follow the semantics from
[mypy](https://github.com/python/mypy/pull/1705).

Example:

```python
def f() -> int:
    return 10

# error: [redundant-cast] "Value is already of type `int`"
cast(int, f())
```
2025-04-01 00:37:25 +00:00
Matthew Mckee
3ad123bc23
[red-knot] Narrowing on in tuple[...] and in str (#17059)
## Summary

Part of #13694

Seems there a bit more to cover regarding `in` and other types, but i
can cover them in different PRs

## Test Plan
Add `in.md` file in narrowing conditionals folder

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-31 23:38:09 +00:00
Matthew Mckee
4a6fa5fc27
[red-knot] Add assignability of function literals to callables (#17095)
## Summary

Part  of #16953

## Test Plan

Update is_assignable_to.md

---------

Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
2025-03-31 15:42:42 +00:00
David Peter
2d7f118f52
[red-knot] Binary operator inference: generalize code for non-instances (#17081)
## Summary

Generalize the rich-comparison fallback code for binary operator
inference. This gets rid of one `todo_type!(…)` and implements the last
remaining failing case from
https://github.com/astral-sh/ruff/issues/14200.

closes https://github.com/astral-sh/ruff/issues/14200

## Test Plan

New Markdown tests.
2025-03-31 13:01:25 +02:00
David Peter
3d1e5676fb
[red-knot] Add ParamSpecArgs and ParamSpecKwargs as KnownClass (#17086)
## Summary

In preparation for #17017, where we will need them to suppress new false
positives (once we understand the `ParamSpec.args`/`ParamSpec.kwargs`
properties).

## Test Plan

Tested on branch #17017
2025-03-31 10:52:23 +00:00
Mike Perlov
5c1fab0661
Fix member lookup for unions & intersections ignoring policy (#17066)
## Summary

A quick fix for how union/intersection member search ins performed in
Knot.

## Test Plan

* Added a dunder method call test for Union, which exhibits the error
* Also added an intersection error, but it is not triggering currently
due to `call` logic not being fully implemented for intersections.

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-03-31 09:40:47 +02:00
cake-monotone
c6efa93cf7
[red-knot] Handle special case returning NotImplemented (#17034)
## Summary

Closes #16661

This PR includes two changes:

- `NotImplementedType` is now a member of `KnownClass`
- We skip `is_assignable_to` checks for `NotImplemented` when checking
return types

### Limitation

```py
def f(cond: bool) -> int:
    return 1 if cond else NotImplemented
```

The implementation covers cases where `NotImplemented` appears inside a
`Union`.
However, for more complex types (ex. `Intersection`) it will not worked.
In my opinion, supporting such complexity is unnecessary at this point.

## Test Plan

Two `mdtest` files were updated:

- `mdtest/function/return_type.md`
- `mdtest/type_properties/is_singleton.md`

To test `KnownClass`, run:
```bash
cargo test -p red_knot_python_semantic -- types::class::
```
2025-03-30 11:06:12 -07:00
Alex Waygood
93052331b0
[red-knot] Allow CallableTypeFromFunction to display the signatures of callable types that are not function literals (#17047)
I found this helpful for understanding some of the stuff that was going
on in https://github.com/astral-sh/ruff/pull/17005.
2025-03-28 20:23:04 +00:00
Shunsuke Shibayama
aca6254e82
[red-knot] fix eager nested scopes handling (#16916)
## Summary

From #16861, and the continuation of #16915.

This PR fixes the incorrect behavior of
`TypeInferenceBuilder::infer_name_load` in eager nested scopes.

And this PR closes #16341.

## Test Plan

New test cases are added in `annotations/deferred.md`.
2025-03-28 11:11:56 -04:00
Eric Mark Martin
64171744dc
[red-knot] support narrowing on or patterns in matches (#17030)
## Summary

Part of #13694

Narrow in or-patterns by taking the type union of the type constraints
in each disjunct pattern.

## Test Plan

Add new tests to narrow/match.md

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-28 14:27:09 +00:00
Eric Mark Martin
3acf4e716d
[red-knot] support narrowing on constants in matches (#16974)
## Summary

Part of #13694

The implementation here was suspiciously straightforward so please lmk
if I missed something

Also some drive-by changes to DRY things up a bit

## Test Plan

Add new tests to narrow/match.md

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-28 02:36:51 +00:00
Alex Waygood
992a1af4c2
[red-knot] Reduce false positives on super() and enum-class attribute accesses (#17004)
## Summary

This PR adds some branches so that we infer `Todo` types for attribute
access on instances of `super()` and subtypes of `type[Enum]`. It reduces
false positives in the short term until we implement full support for
these features.

## Test Plan

New mdtests added + mypy_primer report
2025-03-27 17:30:56 -04:00
Matthew Mckee
b9a7328789
[red-knot] Make every type a subtype of object (#16960)
## Summary

Mainly for partially fixing #16953

## Test Plan

Update is_subtype tests. And should maybe do these checks for many other
types (is subtype of object but object is not subtype)

---------

Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
2025-03-27 14:24:18 +00:00
Matthew Mckee
aae4d0f3eb
[red-knot] A FunctionType can be a subtype of Callable (but never the other way around) (#16970)
## Summary

Partially fixes #16953

## Test Plan

Update is_subtype_of.md

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-25 22:04:34 +00:00
Alex Waygood
4975c2f027
[red-knot] Fix panic on cyclic * imports (#16958)
## Summary

Further work towards https://github.com/astral-sh/ruff/issues/14169.

We currently panic on encountering cyclic `*` imports. This is easily
fixed using fixpoint iteration.

## Test Plan

Added a test that panics on `main`, but passes with this PR
2025-03-24 18:23:02 +00:00
Dhruv Manilawala
dd5b02aaa2
[red-knot] Fix gradual equivalence for callable types (#16887)
## Summary

As mentioned in
https://github.com/astral-sh/ruff/pull/16698#discussion_r2004920075,
part of #15382, this PR updates the `is_gradual_equivalent_to`
implementation between callable types to be similar to
`is_equivalent_to` and checks other attributes of parameters like name,
optionality, and parameter kind.

## Test Plan

Expand the existing test cases to consider other properties but not all
similar to how the tests are structured for subtyping and assignability.
2025-03-24 23:46:06 +05:30
Alex Waygood
e87fee4b3b
[red-knot] Add initial support for * imports (#16923)
## Summary

This PR adds initial support for `*` imports to red-knot. The approach
is to implement a standalone query, called from semantic indexing, that
visits the module referenced by the `*` import and collects all
global-scope public names that will be imported by the `*` import. The
`SemanticIndexBuilder` then adds separate definitions for each of these
names, all keyed to the same `ast::Alias` node that represents the `*`
import.

There are many pieces of `*`-import semantics that are still yet to be
done, even with this PR:
- This PR does not attempt to implement any of the semantics to do with
`__all__`. (If a module defines `__all__`, then only the symbols
included in `__all__` are imported, _not_ all public global-scope
symbols.
- With the logic implemented in this PR as it currently stands, we
sometimes incorrectly consider a symbol bound even though it is defined
in a branch that is statically known to be dead code, e.g. (assuming the
target Python version is set to 3.11):

  ```py
  # a.py

  import sys

  if sys.version_info < (3, 10):
      class Foo: ...

  ```

  ```py
  # b.py

  from a import *

  print(Foo)  # this is unbound at runtime on 3.11,
# but we currently consider it bound with the logic in this PR
  ```

Implementing these features is important, but is for now deferred to
followup PRs.

Many thanks to @ntBre, who contributed to this PR in a pairing session
on Friday!

## Test Plan

Assertions in existing mdtests are adjusted, and several new ones are
added.
2025-03-24 17:15:58 +00:00
Alex Waygood
66d0cf2a72
[red-knot] Add more tests for * imports (#16955)
## Summary

This PR separates out the entirely new tests from
https://github.com/astral-sh/ruff/pull/16923 into a standalone PR. I'll
rebase https://github.com/astral-sh/ruff/pull/16923 on top of this
branch.

The reasons for separating it out are:
- It should make it clearer to see in
<https://github.com/astral-sh/ruff/pull/16923> exactly how the
functionality is changing (we can see the assertions in the tests
_change_, which isn't so obvious if the tests are entirely new)
- The diff on <https://github.com/astral-sh/ruff/pull/16923> is getting
pretty big; this should reduce the diff on that PR somewhat
- These tests seem useful in and of themselves, so even if we need to do
a wholesale revert of <https://github.com/astral-sh/ruff/pull/16923> for
whatever reason, it'll be nice to keep the tests

## Test Plan

`cargo test -p red_knot_python_semantic`
2025-03-24 16:39:16 +00:00
John Stilley
3899f7156f
Fixing more spelling errors (#16926)
## Summary

Here I fix the last English spelling errors I could find in the repo.

Again, I am trying not to touch variable/function names, or anything
that might be misspelled in the API. The goal is to make this PR safe
and easy to merge.

## Test Plan

I have run all the unit tests. Though, again, all of the changes I make
here are to docs and docstrings. I make no code changes, which I believe
should greatly mitigate the testing concerns.
2025-03-23 10:55:14 -07:00
InSync
902d86e79e
[red-knot] Do not emit invalid-return-type for abstract functions (#16900)
## Summary

Resolves #16895.

`abstractmethod` is now a `KnownFunction`. When a function is decorated
by `abstractmethod` or when the parent class inherits directly from
`Protocol`, `invalid-return-type` won't be emitted for that function.

## Test Plan

Markdown tests.

---------

Co-authored-by: Carl Meyer <carl@oddbird.net>
2025-03-23 17:51:10 +00:00
Matthew Mckee
08a0995108
[red-knot] Disambiguate display for intersection types (#16914)
## Summary

Fixes #16912 

Create a new type `DisplayMaybeParenthesizedType` that is now used in
Union and Intersection display

## Test Plan

Update callable annotations
2025-03-23 07:18:30 -07:00
Shunsuke Shibayama
ee51c2a389
[red-knot] fix ordering of ClassDef semantic index building (#16915)
## Summary

From #16861

This PR fixes the incorrect `ClassDef` handling of
`SemanticIndexBuilder::visit_stmt`, which fixes some of the incorrect
behavior of referencing the class itself in the class scope (a complete
fix requires a different fix, which will be done in the another PR).

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-23 13:23:12 +00:00
John Stilley
c35f2bfe32
Fixing various spelling errors (#16924)
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## Summary

This is a cleanup PR. I am fixing various English language spelling
errors. This is mostly in docs and docstrings.

## Test Plan

The usual CI tests were run. I tried to build the docs (though I had
some troubles there). The testing needs here are, I trust, very low
impact. (Though I would happily test more.)
2025-03-23 08:08:40 +00:00
Dhruv Manilawala
0360c6b219
[red-knot] Support calling a typing.Callable (#16888)
## Summary

Part of #15382, this PR adds support for calling a variable that's
annotated with `typing.Callable`.

## Test Plan

Add test cases in a new `call/annotation.md` file.
2025-03-23 02:39:33 +05:30
Dhruv Manilawala
1cffb323bc
[red-knot] Check assignability for two callable types (#16845)
## Summary

Part of #15382

This PR adds support for checking the assignability of two general
callable types.

This is built on top of #16804 by including the gradual parameters check
and accepting a function that performs the check between the two types.

## Test Plan

Update `is_assignable_to.md` with callable types section.
2025-03-23 02:28:44 +05:30
Matthew Mckee
92028efe3d
[red-knot] Fix disambiguate display for union types (#16907)
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## Summary

When callables are displayed in unions, like:
```py
from typing import Callable


def foo(x: Callable[[], int] | None):
    # red-knot: Revealed type is `() -> int | None` [revealed-type]
    reveal_type(x)
```

This leaves the type rather ambiguous, to fix this we can add
parenthesis to callable type in union

Fixes #16893

## Test Plan

Update callable annotations tests

---------

Co-authored-by: Micha Reiser <micha@reiser.io>
2025-03-22 13:08:51 +01:00
Alex Waygood
d21d639ee0
[red-knot] Avoid false-positive diagnostics on * import statements (#16899)
## Summary

This PR removes false-positive diagnostics for `*` imports. Currently we
always emit a diagnostic for these statements unless the module we're
importing from has a symbol named `"*"` in its symbol table for the
global scope. (And if we were doing everything correctly, no module ever
would have a symbol named `"*"` in its global scope!)

The fix here is sort-of hacky and won't be what we'll want to do
long-term. However, I think it's useful to do this as a first step
since:
- It significantly reduces false positives when running on code that
uses `*` imports
- It "resets" the tests to a cleaner state with many fewer TODOs, making
it easier to see what the hard work is that's still to be done.

## Test Plan

`cargo test -p red_knot_python_semantic`
2025-03-21 14:41:49 +00:00
Alex Waygood
14eb4cac88
[red-knot] Add failing tests for * imports (#16873)
## Summary

This PR adds a suite of tests for wildcard (`*`) imports. The tests
nearly all fail for now, and those that don't, ahem, pass for the wrong
reasons...

I've tried to add TODO comments in all instances for places where we are
currently inferring the incorrect thing, incorrectly emitting a
diagnostic, or emitting a diagnostic with a bad error message.

## Test Plan

`cargo test -p red_knot_python_semantic`
2025-03-21 14:17:15 +00:00
Douglas Creager
c03c28d199
[red-knot] Break up call binding into two phases (#16546)
This breaks up call binding into two phases:

- **_Matching parameters_** just looks at the names and kinds
(positional/keyword) of each formal and actual parameters, and matches
them up. Most of the current call binding errors happen during this
phase.

- Once we have matched up formal and actual parameters, we can **_infer
types_** of each actual parameter, and **_check_** that each one is
assignable to the corresponding formal parameter type.

As part of this, we add information to each formal parameter about
whether it is a type form or not. Once [PEP
747](https://peps.python.org/pep-0747/) is finalized, we can hook that
up to this internal type form representation. This replaces the
`ParameterExpectations` type, which did the same thing in a more ad hoc
way.

While we're here, we add a new fluent API for building `Parameter`s,
which makes our signature constructors a bit nicer to read. We also
eliminate a TODO where we were consuming types from the argument list
instead of the bound parameter list when evaluating our special-case
known functions.

Closes #15460

---------

Co-authored-by: Micha Reiser <micha@reiser.io>
2025-03-21 09:38:11 -04:00
Dhruv Manilawala
04a8756379
[red-knot] Check subtype relation between callable types (#16804)
## Summary

Part of #15382

This PR adds support for checking the subtype relationship between the
two callable types.

The main source of reference used for implementation is
https://typing.python.org/en/latest/spec/callables.html#assignability-rules-for-callables.

The implementation is split into two phases:
1. Check all the positional parameters which includes positional-only,
standard (positional or keyword) and variadic kind
2. Collect all the keywords in a `HashMap` to do the keyword parameters
check via name lookup

For (1), there's a helper struct which is similar to `.zip_longest`
(from `itertools`) except that it allows control over one of the
iterator as that's required when processing a variadic parameter. This
is required because positional parameters needs to be checked as per
their position between the two callable types. The struct also keeps
track of the current iteration element because when the loop is exited
(to move on to the phase 2) the current iteration element would be
carried over to the phase 2 check.

This struct is internal to the `is_subtype_of` method as I don't think
it makes sense to expose it outside. It also allows me to use "self" and
"other" suffixed field names as that's only relevant in that context.

## Test Plan

Add extensive tests in markdown.

Converted all of the code snippets from
https://typing.python.org/en/latest/spec/callables.html#assignability-rules-for-callables
to use `knot_extensions.is_subtype_of` and verified the result.
2025-03-21 03:27:22 +00:00
Dhruv Manilawala
193c38199e
[red-knot] Check whether two callable types are equivalent (#16698)
## Summary

This PR checks whether two callable types are equivalent or not.

This is required because for an equivalence relationship, the default
value does not necessarily need to be the same but if the parameter in
one of the callable has a default value then the corresponding parameter
in the other callable should also have a default value. This is the main
reason a manual implementation is required.

And, as per https://typing.python.org/en/latest/spec/callables.html#id4,
the default _type_ doesn't participate in a subtype relationship, only
the optionality (required or not) participates. This means that the
following two callable types are equivalent:

```py
def f1(a: int = 1) -> None: ...
def f2(a: int = 2) -> None: ...
```

Additionally, the name of positional-only, variadic and keyword-variadic
are not required to be the same for an equivalence relation.

A potential solution to avoid the manual implementation would be to only
store whether a parameter has a default value or not but the type is
currently required to check for assignability.

## Test plan

Add tests for callable types in `is_equivalent_to.md`
2025-03-21 03:19:07 +00:00
Matthew Mckee
63e78b41cd
[red-knot] Ban most Type::Instance types in type expressions (#16872)
## Summary

Catch some Instances, but raise type error for the rest of them
Fixes #16851 

## Test Plan

Extend invalid.md in annotations

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-03-20 15:19:56 -07:00
Alex Waygood
296d67a496
Special-case value-expression inference of special form subscriptions (#16877)
## Summary

Currently for something like `X = typing.Tuple[str, str]`, we infer the
value of `X` as `object`. That's because `Tuple` (like many of the
symbols in the typing module) is annotated as a `_SpecialForm` instance
in typeshed's stubs:


23382f5f8c/crates/red_knot_vendored/vendor/typeshed/stdlib/typing.pyi (L215)

and we don't understand implicit type aliases yet, and the stub for
`_SpecialForm.__getitem__` says it always returns `object`:


23382f5f8c/crates/red_knot_vendored/vendor/typeshed/stdlib/typing.pyi (L198-L200)

We have existing false positives in our test suite due to this:


23382f5f8c/crates/red_knot_python_semantic/resources/mdtest/annotations/annotated.md (L76-L78)

and it's causing _many_ new false positives in #16872, which tries to
make our annotation-expression parsing stricter in some ways.

This PR therefore adds some small special casing for `KnownInstanceType`
variants that fallback to `_SpecialForm`, so that these false positives
can be avoided.

## Test Plan

Existing mdtest altered.

Cc. @MatthewMckee4
2025-03-20 21:46:02 +00:00
Shunsuke Shibayama
23382f5f8c
[red-knot] add test cases result in false positive errors (#16856)
## Summary

From #16641

The previous PR attempted to fix the errors presented in this PR, but as
discussed in the conversation, it was concluded that the approach was
undesirable and that further work would be needed to fix the errors with
a correct general solution.

In this PR, I instead add the test cases from the previous PR as TODOs,
as a starting point for future work.

## Test Plan

---------

Co-authored-by: Carl Meyer <carl@oddbird.net>
2025-03-20 17:17:54 +00:00
Matthew Mckee
4ed93b4311
Show more precise messages in invalid type expressions (#16850)
## Summary

Some error messages were not very specific; this PR improves them

## Test Plan

New mdtests added; existing mdtests tweaked
2025-03-19 17:00:30 +00:00
Alex Waygood
a3f3d734a1
[red-knot] Ban list literals in most contexts in type expressions (#16847)
## Summary

This PR reworks `TypeInferenceBuilder::infer_type_expression()` so that
we emit diagnostics when encountering a list literal in a type
expression. The only place where a list literal is allowed in a type
expression is if it appears as the first argument to `Callable[]`, and
`Callable` is already heavily special-cased in our type-expression
parsing.

In order to ensure that list literals are _always_ allowed as the
_first_ argument to `Callabler` (but never allowed as the second, third,
etc. argument), I had to do some refactoring of our type-expression
parsing for `Callable` annotations.

## Test Plan

New mdtests added, and existing ones updated
2025-03-19 14:42:42 +00:00
Matthew Mckee
3a5f1d46c0
[red-knot] Make' Type::in_type_expression()' exhaustive for Type::KnownInstance (#16836)
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## Summary

fixes #15048 
We want to handle more types from Type::KnownInstance 

## Test Plan

Add tests for each type added explicitly in the match

---------

Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
2025-03-19 07:36:28 -07:00
Dhruv Manilawala
a69f6240cc
[red-knot] Infer lambda return type as Unknown (#16695)
## Summary

Part of #15382

This PR infers the return type `lambda` expression as `Unknown`. In the
future, it would be more useful to infer the expression type considering
the surrounding context (#16696).

## Test Plan

Update existing test cases from `@todo` to the (verified) return type.
2025-03-18 22:48:10 +05:30
Matthew Mckee
ab3ec4de6a
[red-knot] Emit errors for more AST nodes that are invalid (or only valid in specific contexts) in type expressions (#16822)
## Summary

Add error messages for invalid nodes in type expressions

Fixes #16816 

## Test Plan

Extend annotations/invalid.md to handle these invalid AST nodes error
messages
2025-03-18 17:16:50 +00:00
Andrew Gallant
bd9eab059f red_knot: update diagnostic output snapshots
These should all be minor cosmetic changes. To summarize:

* In many cases, `-` was replaced with `^` for primary annotations.
This is because, previously, whether `-` or `^` was used depended
on the severity. But in the new data model, it's based on whether
the annotation is "primary" or not. We could of course change this
in whatever way we want, but I think we should roll with this for now.

* The "secondary messages" in the old API are rendered as
sub-diagnostics. This in turn results in a small change in the output
format, since previously, the secondary messages were represented as
just another snippet. We use sub-diagnostics because that's the intended
way to enforce relative ordering between messages within a diagnostic.

* The "info:" prefix used in some annotation messages has been dropped.
We could re-add this, but I think I like it better without this prefix.

I believe those 3 cover all of the snapshot changes here.
2025-03-17 12:46:49 -04:00