Commit Graph

404 Commits

Author SHA1 Message Date
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?plain=1#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
Douglas Creager 23ccb52fa6
[red-knot] Handle unions of callables better (#16716)
This cleans up how we handle calling unions of types. #16568 adding a
three-level structure for callable signatures (`Signatures`,
`CallableSignature`, and `Signature`) to handle unions and overloads.

This PR updates the bindings side to mimic that structure. What used to
be called `CallOutcome` is now `Bindings`, and represents the result of
binding actual arguments against a possible union of callables.
`CallableBinding` is the result of binding a single, possibly
overloaded, callable type. `Binding` is the result of binding a single
overload.

While we're here, this also cleans up `CallError` greatly. It was
previously extracting error information from the bindings and storing it
in the error result. It is now a simple enum, carrying no data, that's
used as a status code to talk about whether the overall binding was
successful or not. We are now more consistent about walking the binding
itself to get detailed information about _how_ the binding was
unsucessful.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-17 10:35:52 -04:00
Dhruv Manilawala 3ccc8dbbf9
[red-knot] Fix fully static check for callable type (#16803)
## Summary

This PR fixes a bug in the check for fully static callable type where we
would skip unannotated parameter type.

## Test Plan

Add tests using the new `CallableTypeFromFunction` special form.
2025-03-17 20:01:30 +05:30
Alex Waygood 50b66dc025
[red-knot] Stabilize `negation_reverses_subtype_order` property test (#16801)
## Summary

This is a re-creation of https://github.com/astral-sh/ruff/pull/16764 by
@mtshiba, which I closed meaning to immediately reopen (GitHub wasn't
updating the PR with the latest pushed changes), and which GitHub will
not allow me to reopen for some reason. Pasting the summary from that PR
below:

> From https://github.com/astral-sh/ruff/pull/16641
> 
> As stated in this comment
(https://github.com/astral-sh/ruff/pull/16641#discussion_r1996153702),
the current ordering implementation for intersection types is incorrect.
So, I will introduce lexicographic ordering for intersection types.

## Test Plan

One property test stabilised (tested locally with
`QUICKCHECK_TESTS=2000000 cargo test --release -p
red_knot_python_semantic -- --ignored
types::property_tests::stable::negation_reverses_subtype_order`), and
existing mdtests that previously failed now pass.

Primarily-authored-by:
[mtshiba](https://github.com/astral-sh/ruff/commits?author=mtshiba)

---------

Co-authored-by: Shunsuke Shibayama <sbym1346@gmail.com>
2025-03-17 12:33:38 +00:00
Matthew Mckee 24707777af
[red-knot] Emit error if int/float/complex/bytes/boolean literals appear in type expressions outside `typing.Literal[]` (#16765)
## Summary
Fixes https://github.com/astral-sh/ruff/issues/16532

## Test Plan

New mdtest assertions added

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2025-03-17 11:56:16 +00:00
David Peter ebcad6e641
[red-knot] Use `try_call_dunder` for augmented assignment (#16717)
## Summary

Uses the `try_call_dunder` infrastructure for augmented assignment and
fixes the logic to work for types other than `Type::Instance(…)`. This
allows us to infer the correct type here:
```py
x = (1, 2)
x += (3, 4)
reveal_type(x)  # revealed: tuple[Literal[1], Literal[2], Literal[3], Literal[4]]
```
Or in this (extremely weird) scenario:
```py
class Meta(type):
    def __iadd__(cls, other: int) -> str:
        return ""

class C(metaclass=Meta): ...

cls = C
cls += 1

reveal_type(cls)  # revealed: str
```

Union and intersection handling could also be improved here, but I made
no attempt to do so in this PR.

## Test Plan

New MD tests
2025-03-14 20:36:09 +01:00
David Peter fe275725e0
[red-knot] Document current state of attribute assignment diagnostics (#16746)
## Summary

A follow-up to https://github.com/astral-sh/ruff/pull/16705 which
documents various kinds of diagnostics that can appear when assigning to
an attribute.

## Test Plan

New snapshot tests.
2025-03-14 20:34:43 +01:00
Micha Reiser a467e7c8d3
[red-knot] Case sensitive module resolver (#16521)
## Summary

This PR implements the first part of
https://github.com/astral-sh/ruff/discussions/16440. It ensures that Red
Knot's module resolver is case sensitive on all systems.

This PR combines a few approaches:

1. It uses `canonicalize` on non-case-sensitive systems to get the real
casing of a path. This works for as long as no symlinks or mapped
network drives (the windows `E:\` is mapped to `\\server\share` thingy).
This is the same as what Pyright does
2. If 1. fails, fall back to recursively list the parent directory and
test if the path's file name matches the casing exactly as listed in by
list dir. This is the same approach as CPython takes in its module
resolver. The main downside is that it requires more syscalls because,
unlike CPython, we Red Knot needs to invalidate its caches if a file
name gets renamed (CPython assumes that the folders are immutable).

It's worth noting that the file watching test that I added that renames
`lib.py` to `Lib.py` currently doesn't pass on case-insensitive systems.
Making it pass requires some more involved changes to `Files`. I plan to
work on this next. There's the argument that landing this PR on its own
isn't worth it without this issue being addressed. I think it's still a
good step in the right direction even when some of the details on how
and where the path case sensitive comparison is implemented.

## Test plan

I added multiple integration tests (including a failing one). I tested
that the `case-sensitivity` detection works as expected on Windows,
MacOS and Linux and that the fast-paths are taken accordingly.
2025-03-14 19:16:44 +00:00
David Peter a22d206db2
[red-knot] Preliminary tests for typing.Final (#15917)
## Summary

WIP.

Adds some preliminary tests for `typing.Final`.

## Test Plan

New MD tests
2025-03-14 12:30:13 +01:00
cake-monotone 270318c2e0
[red-knot] fix: improve type inference for binary ops on tuples (#16725)
## Summary

This PR includes minor improvements to binary operation inference,
specifically for tuple concatenation.

### Before

```py
reveal_type((1, 2) + (3, 4))  # revealed: @Todo(return type of decorated function)
# If TODO is ignored, the revealed type would be `tuple[1|2|3|4, ...]`
```

The `builtins.tuple` type stub defines `__add__`, but it appears to only
work for homogeneous tuples. However, I think this limitation is not
ideal for many use cases.

### After

```py
reveal_type((1, 2) + (3, 4))  # revealed: tuple[Literal[1], Literal[2], Literal[3], Literal[4]]
```

## Test Plan

### Added
- `mdtest/binary/tuples.md`

### Affected
- `mdtest/slots.md` (a test have been moved out of the `False-Negative`
block.)
2025-03-14 12:29:57 +01:00
David Peter d03b12e711
[red-knot] Assignments to attributes (#16705)
## Summary

This changeset adds proper support for assignments to attributes:
```py
obj.attr = value
```

In particular, the following new features are now available:

* We previously didn't raise any errors if you tried to assign to a
non-existing attribute `attr`. This is now fixed.
* If `type(obj).attr` is a data descriptor, we now call its `__set__`
method instead of trying to assign to the load-context type of
`obj.attr`, which can be different for data descriptors.
* An initial attempt was made to support unions and intersections, as
well as possibly-unbound situations. There are some remaining TODOs in
tests, but they only affect edge cases. Having nested diagnostics would
be one way that could help solve the remaining cases, I believe.

## Follow ups

The following things are planned as follow-ups:

- Write a test suite with snapshot diagnostics for various attribute
assignment errors
- Improve the diagnostics. An easy improvement would be to highlight the
right hand side of the assignment as a secondary span (with the rhs type
as additional information). Some other ideas are mentioned in TODO
comments in this PR.
- Improve the union/intersection/possible-unboundness handling
- Add support for calling custom `__setattr__` methods (see new false
positive in the ecosystem results)

## Ecosystem changes

Some changes are related to assignments on attributes with a custom
`__setattr__` method (see above). Since we didn't notice missing
attributes at all in store context previously, these are new.

The other changes are related to properties. We previously used their
read-context type to test the assignment. That results in weird error
messages, as we often see assignments to `self.property` and then we
think that those are instance attributes *and* descriptors, leading to
union types. Now we properly look them up on the meta type, see the
decorated function, and try to overwrite it with the new value (as we
don't understand decorators yet). Long story short: the errors are still
weird, we need to understand decorators to make them go away.

## Test Plan

New Markdown tests
2025-03-14 12:15:41 +01:00
Carl Meyer abaa18993b
[red-knot] handle cycles in MRO/bases resolution (#16693)
There can be semi-cyclic inheritance patterns (e.g. recursive generics)
that are not technically inheritance cycles, but that can cause us to
hit Salsa query cycles in evaluating a type's MRO. Add fixed-point
handling to these MRO-related queries so we don't panic on these cycles.

The details of what queries we hit in what order in this case will
change as we implement support for generics, but ultimately we will
probably need cycle handling for all queries that can re-enter type
inference, otherwise we are susceptible to small changes in query
execution order causing panics.

Fixes #14333
Further reduces the panicking set of seeds in #14737
2025-03-13 08:16:03 -07:00
Dhruv Manilawala 58d5fe982e
[red-knot] Check gradual equivalence between callable types (#16634) 2025-03-13 08:16:51 +05:30
Dhruv Manilawala 08fa9b4a90
[red-knot] Add `CallableTypeFromFunction` special form (#16683)
## Summary

This PR adds a new `CallableTypeFromFunction` special form to allow
extracting the abstract signature of a function literal i.e., convert a
`Type::Function` into a `Type::Callable` (`CallableType::General`).

This is done to support testing the `is_gradual_equivalent_to` type
relation specifically the case we want to make sure that a function that
has parameters with no annotations and does not have a return type
annotation is gradual equivalent to `Callable[[Any, Any, ...], Any]`
where the number of parameters should match between the function literal
and callable type.

Refer
https://github.com/astral-sh/ruff/pull/16634#discussion_r1989976692

### Bikeshedding

The name `CallableTypeFromFunction` is a bit too verbose. A possibly
alternative from Carl is `CallableTypeOf` but that would be similar to
`TypeOf` albeit with a limitation that the former only accepts function
literal types and errors on other types.

Some other alternatives:
* `FunctionSignature`
* `SignatureOf` (similar issues as `TypeOf`?)
* ...

## Test Plan

Update `type_api.md` with a new section that tests this special form,
both invalid and valid forms.
2025-03-13 07:49:34 +05:30
David Peter 083df0cf84
[red-knot] Support custom `__getattr__` methods (#16668)
## Summary

Add support for calling custom `__getattr__` methods in case an
attribute is not otherwise found. This allows us to get rid of many
ecosystem false positives where we previously emitted errors when
accessing attributes on `argparse.Namespace`.

closes #16614

## Test Plan

* New Markdown tests
* Observed expected ecosystem changes (the changes for `arrow` also look
fine, since the `Arrow` class has a custom [`__getattr__`
here](1d70d00919/arrow/arrow.py (L802-L815)))
2025-03-12 13:44:11 +01:00
Carl Meyer a176c1ac80
[red-knot] use fixpoint iteration for all cycles (#14029)
Pulls in the latest Salsa main branch, which supports fixpoint
iteration, and uses it to handle all query cycles.

With this, we no longer need to skip any corpus files to avoid panics.

Latest perf results show a 6% incremental and 1% cold-check regression.
This is not a "no cycles" regression, as tomllib and typeshed do trigger
some definition cycles (previously handled by our old
`infer_definition_types` fallback to `Unknown`). We don't currently have
a benchmark we can use to measure the pure no-cycles regression, though
I expect there would still be some regression; the fixpoint iteration
feature in Salsa does add some overhead even for non-cyclic queries.

I think this regression is within the reasonable range for this feature.
We can do further optimization work later, but I don't think it's the
top priority right now. So going ahead and acknowledging the regression
on CodSpeed.

Mypy primer is happy, so this doesn't regress anything on our
currently-checked projects. I expect it probably unlocks adding a number
of new projects to our ecosystem check that previously would have
panicked.

Fixes #13792
Fixes #14672
2025-03-12 12:41:40 +00:00
David Peter a6572a57c4
[red-knot] Attribute access on intersection types (#16665)
## Summary

Implements attribute access on intersection types, which didn't
previously work. For example:

```py
from typing import Any

class P: ...
class Q: ...

class A:
    x: P = P()

class B:
    x: Any = Q()

def _(obj: A):
    if isinstance(obj, B):
        reveal_type(obj.x)  # revealed: P & Any
```

Refers to [this comment].

[this comment]:
https://github.com/astral-sh/ruff/pull/16416#discussion_r1985040363

## Test Plan

New Markdown tests
2025-03-12 13:20:17 +01:00
Joey Bar b250304ad3
[red-knot] Improve is_disjoint for two intersections (#16636)
## Summary

Background - as a follow up to #16611 I noticed that there's a lot of
code duplicated between the `is_assignable_to` and `is_subtype_of`
functions and considered trying to merge them.

[A subtype and an assignable type are pretty much the
same](https://typing.python.org/en/latest/spec/concepts.html#the-assignable-to-or-consistent-subtyping-relation),
except that subtypes are by definition fully static, so I think we can
replace the whole of `is_subtype_of` with:

```
if !self.is_fully_static(db) || !target.is_fully_static(db) {
    return false;
}
return self.is_assignable_to(target)
```

if we move all of the logic to is_assignable_to and delete duplicate
code. Then we can discuss if it even makes sense to have a separate
is_subtype_of function (I think the answer is yes since it's used by a
bunch of other places, but we may be able to basically rip out the
concept).

Anyways while playing with combining the functions I noticed is that the
handling of Intersections in `is_subtype_of` has a special case for two
intersections, which I didn't include in the last PR - rather I first
handled right hand intersections before left hand, which should properly
handle double intersections (hand-wavy explanation I can justify if
needed - (A & B & C) is assignable to (A & B) because the left is
assignable to both A and B, but none of A, B, or C is assignable to (A &
B)).

I took a look at what breaks if I remove the handling for double
intersections, and the reason it is needed is because is_disjoint does
not properly handle intersections with negative conditions (so instead
`is_subtype_of` basically implements the check correctly).

This PR adds support to is_disjoint for properly checking negative
branches, which also lets us simplify `is_subtype_of`, bringing it in
line with `is_assignable_to`

## Test Plan

Added a bunch of tests, most of which failed before this fix

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-12 12:13:04 +00:00
David Peter 11b5cbcd2f
[red-knot] Restructure attribute-access and descriptor-protocol test suites. (#16664)
## Summary

This is a pure restructuring of the `attributes.md` and
`descriptor_protocol.md` test suites. They have grown organically and I
didn't want to make major structural changes in my recent PR to keep the
diff clean.
2025-03-12 09:52:21 +01:00
David Peter 860b95a318
[red-knot] Binary operator inference for union types (#16601)
## Summary

Properly handle binary operator inference for union types.

This fixes a bug I noticed while looking at ecosystem results. The MRE
version of it is this:

```py
def sub(x: float, y: float):
    # Red Knot: Operator `-` is unsupported between objects of type `int | float` and `int | float`
    return x - y
```

## Test Plan

- New Markdown tests.
- Expected diff in the ecosystem checks
2025-03-12 08:21:54 +01:00
Dhruv Manilawala 6de2b2873b
[red-knot] Check if callable type is fully static (#16633)
## Summary

Part of #15382 

This PR adds the check for whether a callable type is fully static or
not.

A callable type is fully static if all of the parameter types are fully
static _and_ the return type is fully static _and_ if it does not use
the gradual form (`...`) for its parameters.

## Test Plan

Update `is_fully_static.md` with callable types.

It seems that currently this test is grouped into either fully static or
not, I think it would be useful to split them up in groups like
callable, etc. I intentionally avoided that in this PR but I'll put up a
PR for an appropriate split.

Note: I've an explicit goal of updating the property tests with the new
callable types once all relations are implemented.
2025-03-12 12:13:22 +05:30
Dhruv Manilawala 6b84253679
[red-knot] Callable member lookup, meta type impl (#16618)
## Summary

This PR is a follow-up to https://github.com/astral-sh/ruff/pull/16493
that implements member lookup for the general callable type.

Based on the discussion around [member lookup
here](https://github.com/astral-sh/ruff/pull/16493#discussion_r1982041180)
and [`.to_meta_type()`
here](https://github.com/astral-sh/ruff/pull/16493#discussion_r1985104664).

## Test Plan

Add a new test cases.
2025-03-12 12:01:38 +05:30
Carl Meyer 0340e23395
[red-knot] remove redundant sentence in test (#16660)
Removes a redundant sentence I accidentally left in the test suite from
in #16540 (my mistake).
2025-03-12 04:20:31 +00:00
Shunsuke Shibayama 78b5f0b165
[red-knot] detect invalid return type (#16540)
## Summary

This PR closes #16248.

If the return type of the function isn't assignable to the one
specified, an `invalid-return-type` error occurs.
I thought it would be better to report this as a different kind of error
than the `invalid-assignment` error, so I defined this as a new error.

## Test Plan

All type inconsistencies in the test cases have been replaced with
appropriate ones.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-12 01:58:59 +00:00
Douglas Creager e17cd350b6
[red-knot] Support multiple overloads when binding parameters at call sites (#16568)
This updates the `Signature` and `CallBinding` machinery to support
multiple overloads for a callable. This is currently only used for
`KnownFunction`s that we special-case in our type inference code. It
does **_not_** yet update the semantic index builder to handle
`@overload` decorators and construct a multi-signature `Overloads`
instance for real Python functions.

While I was here, I updated many of the `try_call` special cases to use
signatures (possibly overloaded ones now) and `bind_call` to check
parameter lists. We still need some of the mutator methods on
`OverloadBinding` for the special cases where we need to update return
types based on some Rust code.
2025-03-11 15:08:17 -04:00
Joey Bar e8e24310fb
[red-knot] Handle gradual intersection types in assignability (#16611)
## Summary

This mostly fixes #14899

My motivation was similar to the last comment by @sharkdp there. I ran
red_knot on a codebase and the most common error was patterns like this
failing:

```
def foo(x: str): ...

x: Any = ...
if isinstance(x, str):
    foo(x) # Object of type `Any & str` cannot be assigned to parameter 1 (`x`) of function `foo`; expected type `str`
```

The desired behavior is pretty much to ignore Any/Unknown when resolving
intersection assignability - `Any & str` should be assignable to `str`,
and `str` should be assignable to `str & Any`
 
The fix is actually very similar to the existing code in
`is_subtype_of`, we need to correctly handle intersections on either
side, while being careful to handle dynamic types as desired.

This does not fix the second test case from that issue:

```
static_assert(is_assignable_to(Intersection[Unrelated, Any], Not[tuple[Unrelated, Any]]))
```

but that's misleading because the root cause there has nothing to do
with gradual types. I added a simpler test case that also fails:

```
static_assert(is_assignable_to(Unrelated, Not[tuple[Unrelated]]))
```
This is because we don't determine that Unrelated does not subclass from
tuple so we can't rule out this relation. If that logic is improved then
this fix should also handle the case of the intersection

## Test Plan

Added a bunch of is_assignable_to tests, most of which failed before
this fix.
2025-03-11 07:58:56 -07:00
Dhruv Manilawala da069aa00c
[red-knot] Infer `lambda` expression (#16547)
## Summary

Part of https://github.com/astral-sh/ruff/issues/15382

This PR adds support for inferring the `lambda` expression and return
the `CallableType`.

Currently, this is only limited to inferring the parameters and a todo
type for the return type.

For posterity, I tried using the `file_expression_type` to infer the
return type of lambda but it would always lead to cycle. The main reason
is that in `infer_parameter_definition`, the default expression is being
inferred using `file_expression_type`, which is correct, but it then

Take the following source code as an example:
```py
lambda x=1: x
```

Here's how the code will flow:
* `infer_scope_types` for the global scope
* `infer_lambda_expression`
* `infer_expression` for the default value `1`
* `file_expression_type` for the return type using the body expression.
This is because the body creates it's own scope
* `infer_scope_types` (lambda body scope)
* `infer_name_load` for the symbol `x` whose visible binding is the
lambda parameter `x`
* `infer_parameter_definition` for parameter `x`
* `file_expression_type` for the default value `1`
* `infer_scope_types` for the global scope because of the default
expression

This will then reach to `infer_definition` for the parameter `x` again
which then creates the cycle.

## Test Plan

Add tests around `lambda` expression inference.
2025-03-11 11:25:20 +05:30
David Peter c60e8a037a
[red-knot] Add support for calling `type[…]` (#16597)
## Summary

This fixes the non-diagnostics part of #15948.

## Test Plan

New Markdown tests.

Negative diff on the ecosystem checks:

```diff
zipp (https://github.com/jaraco/zipp)
- error: lint:call-non-callable
-    --> /tmp/mypy_primer/projects/zipp/zipp/__init__.py:393:16
-     |
- 392 |     def _next(self, at):
- 393 |         return self.__class__(self.root, at)
-     |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Object of type `type[Unknown]` is not callable
- 394 |
- 395 |     def is_dir(self):
-     |
- 
- Found 9 diagnostics
+ Found 8 diagnostics

arrow (https://github.com/arrow-py/arrow)
+     |
+     |
+ warning: lint:unused-ignore-comment
+    --> /tmp/mypy_primer/projects/arrow/arrow/arrow.py:576:66
+ 574 |                 values.append(1)
+ 575 |
+ 576 |             floor = self.__class__(*values, tzinfo=self.tzinfo)  # type: ignore[misc]
+     |                                                                  -------------------- Unused blanket `type: ignore` directive
+ 577 |
+ 578 |             if frame_absolute == "week":
- error: lint:call-non-callable
-     --> /tmp/mypy_primer/projects/arrow/arrow/arrow.py:1080:16
-      |
- 1078 |           dt = self._datetime.astimezone(tz)
- 1079 |
- 1080 |           return self.__class__(
-      |  ________________^
- 1081 | |             dt.year,
- 1082 | |             dt.month,
- 1083 | |             dt.day,
- 1084 | |             dt.hour,
- 1085 | |             dt.minute,
- 1086 | |             dt.second,
- 1087 | |             dt.microsecond,
- 1088 | |             dt.tzinfo,
- 1089 | |             fold=getattr(dt, "fold", 0),
- 1090 | |         )
-      | |_________^ Object of type `type[Unknown]` is not callable
- 1091 |
- 1092 |       # string output and formatting
-      |

black (https://github.com/psf/black)
- 
-     |
-     |
- error: lint:call-non-callable
-    --> /tmp/mypy_primer/projects/black/src/blib2to3/pgen2/grammar.py:135:15
- 133 |         Copy the grammar.
- 134 |         """
- 135 |         new = self.__class__()
-     |               ^^^^^^^^^^^^^^^^ Object of type `type[@Todo]` is not callable
- 136 |         for dict_attr in (
- 137 |             "symbol2number",
- Found 328 diagnostics
+ Found 327 diagnostics
```
2025-03-10 13:24:13 +01:00
Alex Waygood 335b264fe2
[red-knot] Consistent spelling of "metaclass" and "meta-type" (#16576)
## Summary

Fixes a small nit of mine -- we are currently inconsistent in our
spelling between "metaclass" and "meta class", and between "meta type"
and "meta-type". This PR means that we consistently use "metaclass" and
"meta-type".

## Test Plan

`uvx pre-commit run -a`
2025-03-09 12:30:32 +00:00
Dhruv Manilawala 0361021863
[red-knot] Understand `typing.Callable` (#16493)
## Summary

Part of https://github.com/astral-sh/ruff/issues/15382

This PR implements a general callable type that wraps around a
`Signature` and it uses that new type to represent `typing.Callable`.

It also implements `Display` support for `Callable`. The format is as:
```
([<arg name>][: <arg type>][ = <default type>], ...) -> <return type>
```

The `/` and `*` separators are added at the correct boundary for
positional-only and keyword-only parameters. Now, as `typing.Callable`
only has positional-only parameters, the rendered signature would be:

```py
Callable[[int, str], None]
# (int, str, /) -> None
```

The `/` separator represents that all the arguments are positional-only.

The relationship methods that check assignability, subtype relationship,
etc. are not yet implemented and will be done so as a follow-up.

## Test Plan

Add test cases for display support for `Signature` and various mdtest
for `typing.Callable`.
2025-03-08 03:58:52 +00:00
Eric Mark Martin 24c8b1242e
[red-knot] Support unpacking `with` target (#16469)
## Summary

Resolves #16365

Add support for unpacking `with` statement targets.

## Test Plan

Added some test cases, alike the ones added by #15058.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-08 02:36:35 +00:00
David Peter 820a31af5d
[red-knot] Attribute access and the descriptor protocol (#16416)
## Summary

* Attributes/method are now properly looked up on metaclasses, when
called on class objects
* We properly distinguish between data descriptors and non-data
descriptors (but we do not yet support them in store-context, i.e.
`obj.data_descr = …`)
* The descriptor protocol is now implemented in a single unified place
for instances, classes and dunder-calls. Unions and possibly-unbound
symbols are supported in all possible stages of the process by creating
union types as results.
* In general, the handling of "possibly-unbound" symbols has been
improved in a lot of places: meta-class attributes, attributes,
descriptors with possibly-unbound `__get__` methods, instance
attributes, …
* We keep track of type qualifiers in a lot more places. I anticipate
that this will be useful if we import e.g. `Final` symbols from other
modules (see relevant change to typing spec:
https://github.com/python/typing/pull/1937).
* Detection and special-casing of the `typing.Protocol` special form in
order to avoid lots of changes in the test suite due to new `@Todo`
types when looking up attributes on builtin types which have `Protocol`
in their MRO. We previously
looked up attributes in a wrong way, which is why this didn't come up
before.

closes #16367
closes #15966

## Context

The way attribute lookup in `Type::member` worked before was simply
wrong (mostly my own fault). The whole instance-attribute lookup should
probably never have been integrated into `Type::member`. And the
`Type::static_member` function that I introduced in my last descriptor
PR was the wrong abstraction. It's kind of fascinating how far this
approach took us, but I am pretty confident that the new approach
proposed here is what we need to model this correctly.

There are three key pieces that are required to implement attribute
lookups:

- **`Type::class_member`**/**`Type::find_in_mro`**: The
`Type::find_in_mro` method that can look up attributes on class bodies
(and corresponding bases). This is a partial function on types, as it
can not be called on instance types like`Type::Instance(…)` or
`Type::IntLiteral(…)`. For this reason, we usually call it through
`Type::class_member`, which is essentially just
`type.to_meta_type().find_in_mro(…)` plus union/intersection handling.
- **`Type::instance_member`**: This new function is basically the
type-level equivalent to `obj.__dict__[name]` when called on
`Type::Instance(…)`. We use this to discover instance attributes such as
those that we see as declarations on class bodies or as (annotated)
assignments to `self.attr` in methods of a class.
- The implementation of the descriptor protocol. It works slightly
different for instances and for class objects, but it can be described
by the general framework:
- Call `type.class_member("attribute")` to look up "attribute" in the
MRO of the meta type of `type`. Call the resulting `Symbol` `meta_attr`
(even if it's unbound).
- Use `meta_attr.class_member("__get__")` to look up `__get__` on the
*meta type* of `meta_attr`. Call it with `__get__(meta_attr, self,
self.to_meta_type())`. If this fails (either the lookup or the call),
just proceed with `meta_attr`. Otherwise, replace `meta_attr` in the
following with the return type of `__get__`. In this step, we also probe
if a `__set__` or `__delete__` method exists and store it in
`meta_attr_kind` (can be either "data descriptor" or "normal attribute
or non-data descriptor").
  - Compute a `fallback` type.
    - For instances, we use `self.instance_member("attribute")`
- For class objects, we use `class_attr =
self.find_in_mro("attribute")`, and then try to invoke the descriptor
protocol on `class_attr`, i.e. we look up `__get__` on the meta type of
`class_attr` and call it with `__get__(class_attr, None, self)`. This
additional invocation of the descriptor protocol on the fallback type is
one major asymmetry in the otherwise universal descriptor protocol
implementation.
- Finally, we look at `meta_attr`, `meta_attr_kind` and `fallback`, and
handle various cases of (possible) unboundness of these symbols.
- If `meta_attr` is bound and a data descriptor, just return `meta_attr`
- If `meta_attr` is not a data descriptor, and `fallback` is bound, just
return `fallback`
- If `meta_attr` is not a data descriptor, and `fallback` is unbound,
return `meta_attr`
- Return unions of these three possibilities for partially-bound
symbols.

This allows us to handle class objects and instances within the same
framework. There is a minor additional detail where for instances, we do
not allow the fallback type (the instance attribute) to completely
shadow the non-data descriptor. We do this because we (currently) don't
want to pretend that we can statically infer that an instance attribute
is always set.

Dunder method calls can also be embedded into this framework. The only
thing that changes is that *there is no fallback type*. If a dunder
method is called on an instance, we do not fall back to instance
variables. If a dunder method is called on a class object, we only look
it up on the meta class, never on the class itself.

## Test Plan

New Markdown tests.
2025-03-07 22:03:28 +01:00
Shunsuke Shibayama 348c196cb3
[red-knot] avoid inferring types if unpacking fails (#16530)
## Summary

This PR closes #15199.

The change I just made is to set all variables to type `Unknown` if
unpacking fails, but in some cases this may be excessive.
For example:

```py
a, b, c = "ab"
reveal_type(a)  # Unknown, but it would be reasonable to think of it as LiteralString
reveal_type(c)  # Unknown
```

```py
# Failed to unpack before the starred expression
(a, b, *c, d, e) = (1,)
reveal_type(a)  # Unknown
reveal_type(b)  # Unknown
...
# Failed to unpack after the starred expression
(a, b, *c, d, e) = (1, 2, 3)
reveal_type(a)  # Unknown, but should it be Literal[1]?
reveal_type(b)  # Unknown, but should it be Literal[2]?
reveal_type(c)  # Todo
reveal_type(d)  # Unknown
reveal_type(e)  # Unknown
```

I will modify it if you think it would be better to make it a different
type than just `Unknown`.

## Test Plan

I have made appropriate modifications to the test cases affected by this
change, and also added some more test cases.
2025-03-07 11:04:44 -08:00
David Peter 0a627ef216
[red-knot] Never is callable and iterable. Arbitrary attributes can be accessed. (#16533)
## Summary

- `Never` is callable
- `Never` is iterable
- Arbitrary attributes can be accessed on `Never`

Split out from #16416 that is going to be required.

## Test Plan

Tests for all properties above.
2025-03-06 15:59:19 +00:00
Micha Reiser ce0018c3cb
Add `OsSystem` support to mdtests (#16518)
## Summary

This PR introduces a new mdtest option `system` that can either be
`in-memory` or `os`
where `in-memory` is the default.

The motivation for supporting `os` is so that we can write OS/system
specific tests
with mdtests. Specifically, I want to write mdtests for the module
resolver,
testing that module resolution is case sensitive. 

## Test Plan

I tested that the case-sensitive module resolver test start failing when
setting `system = "os"`
2025-03-06 10:41:40 +01:00
Micha Reiser 48f906e06c
Add tests for case-sensitive module resolution (#16517)
## Summary

Python's module resolver is case sensitive. 

This PR adds mdtests that assert that our module resolution is case
sensitive.

The tests currently all pass because our in memory file system is case
sensitive.
I'll add support for using the real file system to the mdtest framework
in a separate PR.

This PR also adds support for specifying extra search paths to the
mdtest framework.

## Test Plan
The tests fail when running them using the real file system.
2025-03-06 10:19:23 +01:00
Douglas Creager ebd172e732
[red-knot] Several failing tests for generics (#16509)
To kick off the work of supporting generics, this adds many new
(currently failing) tests, showing the behavior we plan to support.

This is still missing a lot!  Not included:

- typevar tuples
- param specs
- variance
- `Self`

But it's a good start! We can add more failing tests for those once we
tackle these.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-05 17:21:19 -05:00
Shunsuke Shibayama bb44926ca5
[red-knot] Add rule `invalid-type-checking-constant` (#16501)
## Summary

This PR adds more features to #16468.

* Adds a new error rule `invalid-type-checking-constant`, which occurs
when we try to assign a value other than `False` to a user-defined
`TYPE_CHECKING` variable (it is possible to assign `...` in a stub
file).
* Allows annotated assignment to `TYPE_CHECKING`. Only types that
`False` can be assigned to are allowed. However, the type of
`TYPE_CHECKING` will be inferred to be `Literal[True]` regardless of
what the type is specified.

## Test plan

I ran the tests with `cargo test -p red_knot_python_semantic` and
confirmed that all tests passed.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-04 19:49:34 +00:00
Shunsuke Shibayama 1977dda079
[red-knot] respect `TYPE_CHECKING` even if not imported from typing (#16468)
## Summary

This PR closes #15722.

The change is that if the variable `TYPE_CHECKING` is defined/imported,
the type of the variable is interpreted as `Literal[True]` regardless of
what the value is.
This is compatible with the behavior of other type checkers (e.g. mypy,
pyright).

## Test Plan

I ran the tests with `cargo test -p red_knot_python_semantic` and
confirmed that all tests passed.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-04 07:58:29 -08:00
Mike Perlov fdf0915283
[red-knot] treat annotated assignments without RHS in stubs as bindings (#16409) 2025-02-28 16:45:21 +00:00
Alex Waygood 09d0b227fb
[red-knot] Disallow more invalid type expressions (#16427) 2025-02-28 10:04:30 +00:00
Carl Meyer 87d011e1bd
[red-knot] fix non-callable reporting for unions (#16387)
Minor follow-up to https://github.com/astral-sh/ruff/pull/16161

This `not_callable` flag wasn't functional, because it could never be
`false`. It was initialized to `true` and then only ever updated with
`|=`, which can never make it `false`.

Add a test that exercises the case where it _should_ be `false` (all of
the union elements are callable) but `bindings` is also empty (all union
elements have binding errors). Before this PR, the added test wrongly
emits a diagnostic that the union `Literal[f1] | Literal[f2]` is not
callable.

And add a test where a union call results in one binding error and one
not-callable error, where we currently give the wrong result (we show
only the binding error), with a TODO.

Also add TODO comments in a couple other tests where ideally we'd report
more than just one error out of a union call.

Also update the flag name to `all_errors_not_callable` to more clearly
indicate the semantics of the flag.
2025-02-26 07:06:04 -08:00
David Peter 86b01d2d3c
[red-knot] Correct modeling of dunder calls (#16368)
## Summary

Model dunder-calls correctly (and in one single place), by implementing
this behavior (using `__getitem__` as an example).

```py
def getitem_desugared(obj: object, key: object) -> object:
    getitem_callable = find_in_mro(type(obj), "__getitem__")
    if hasattr(getitem_callable, "__get__"):
        getitem_callable = getitem_callable.__get__(obj, type(obj))

    return getitem_callable(key)
```

See the new `calls/dunder.md` test suite for more information. The new
behavior also needs much fewer lines of code (the diff is positive due
to new tests).

## Test Plan

New tests; fix TODOs in existing tests.
2025-02-25 20:38:15 +01:00
David Peter f88328eedd
[red-knot] Handle possibly-unbound instance members (#16363)
## Summary

Adds support for possibly-unbound/undeclared instance members.

## Test Plan

New MD tests.
2025-02-25 20:00:38 +01:00
Alex Waygood 5c007db7e2
[red-knot] Rewrite `Type::try_iterate()` to improve type inference and diagnostic messages (#16321) 2025-02-25 14:02:03 +00:00
David Peter aac79e453a
[red-knot] Better diagnostics for method calls (#16362)
## Summary

Add better error messages and additional spans for method calls. Can be
reviewed commit-by-commit.

before:

```
error: lint:invalid-argument-type
 --> /home/shark/playground/test.py:6:10
  |
5 | c = C()
6 | c.square("hello")  # error: [invalid-argument-type]
  |          ^^^^^^^ Object of type `Literal["hello"]` cannot be assigned to parameter 2 (`x`); expected type `int`
7 |
8 | # import inspect
  |
```

after:

```
error: lint:invalid-argument-type
 --> /home/shark/playground/test.py:6:10
  |
5 | c = C()
6 | c.square("hello")  # error: [invalid-argument-type]
  |          ^^^^^^^ Object of type `Literal["hello"]` cannot be assigned to parameter 2 (`x`) of bound method `square`; expected type `int`
7 |
8 | # import inspect
  |
 ::: /home/shark/playground/test.py:2:22
  |
1 | class C:
2 |     def square(self, x: int) -> int:
  |                      ------ info: parameter declared in function definition here
3 |         return x * x
  |
```

## Test Plan

New snapshot test
2025-02-25 09:58:08 +01:00
Mike Perlov 68991d09a8
[red-knot] Add diagnostic for class-object access to pure instance variables (#16036)
## Summary

Add a diagnostic if a pure instance variable is accessed on a class object. For example

```py
class C:
    instance_only: str

    def __init__(self):
        self.instance_only = "a"

# error: Attribute `instance_only` can only be accessed on instances, not on the class object `Literal[C]` itself.
C.instance_only
```


---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-02-24 15:17:16 +01:00
David Peter 141ba253da
[red-knot] Add support for `@classmethod`s (#16305)
## Summary

Add support for `@classmethod`s.

```py
class C:
    @classmethod
    def f(cls, x: int) -> str:
        return "a"

reveal_type(C.f(1))  # revealed: str
```

## Test Plan

New Markdown tests
2025-02-24 09:55:34 +01:00
Alex Waygood 64effa4aea
[red-knot] Add a regression test for recent improvement to `TypeInferenceBuilder::infer_name_load()` (#16310) 2025-02-21 22:28:42 +00:00
Alex Waygood 224a36f5f3
Teach red-knot that `type(x)` is the same as `x.__class__` (#16301) 2025-02-21 21:05:48 +00:00
Alex Waygood 5347abc766
[red-knot] Generalise special-casing for `KnownClass`es in `Type::bool` (#16300) 2025-02-21 20:46:36 +00:00
Micha Reiser 5fab97f1ef
[red-knot] Diagnostics for incorrect `bool` usages (#16238) 2025-02-21 19:26:05 +01:00
David Peter 3aa7ba31b1
[red-knot] Fix descriptor `__get__` call on class objects (#16304)
## Summary

I spotted a minor mistake in my descriptor protocol implementation where
`C.descriptor` would pass the meta type (`type`) of the type of `C`
(`Literal[C]`) as the owner argument to `__get__`, instead of passing
`Literal[C]` directly.

## Test Plan

New test.
2025-02-21 15:35:41 +01:00
David Peter d2e034adcd
[red-knot] Method calls and the descriptor protocol (#16121)
## Summary

This PR achieves the following:

* Add support for checking method calls, and inferring return types from
method calls. For example:
  ```py
  reveal_type("abcde".find("abc"))  # revealed: int
  reveal_type("foo".encode(encoding="utf-8"))  # revealed: bytes
  
  "abcde".find(123)  # error: [invalid-argument-type]
  
  class C:
      def f(self) -> int:
          pass
  
  reveal_type(C.f)  # revealed: <function `f`>
  reveal_type(C().f)  # revealed: <bound method: `f` of `C`>
  
  C.f()  # error: [missing-argument]
  reveal_type(C().f())  # revealed: int
  ```
* Implement the descriptor protocol, i.e. properly call the `__get__`
method when a descriptor object is accessed through a class object or an
instance of a class. For example:
  ```py
  from typing import Literal
  
  class Ten:
def __get__(self, instance: object, owner: type | None = None) ->
Literal[10]:
          return 10
  
  class C:
      ten: Ten = Ten()
  
  reveal_type(C.ten)  # revealed: Literal[10]
  reveal_type(C().ten)  # revealed: Literal[10]
  ```
* Add support for member lookup on intersection types.
* Support type inference for `inspect.getattr_static(obj, attr)` calls.
This was mostly used as a debugging tool during development, but seems
more generally useful. It can be used to bypass the descriptor protocol.
For the example above:
  ```py
  from inspect import getattr_static
  
  reveal_type(getattr_static(C, "ten"))  # revealed: Ten
  ```
* Add a new `Type::Callable(…)` variant with the following sub-variants:
* `Type::Callable(CallableType::BoundMethod(…))` — represents bound
method objects, e.g. `C().f` above
* `Type::Callable(CallableType::MethodWrapperDunderGet(…))` — represents
`f.__get__` where `f` is a function
* `Type::Callable(WrapperDescriptorDunderGet)` — represents
`FunctionType.__get__`
* Add new known classes:
  * `types.MethodType`
  * `types.MethodWrapperType`
  * `types.WrapperDescriptorType`
  * `builtins.range`

## Performance analysis

On this branch, we do more work. We need to do more call checking, since
we now check all method calls. We also need to do ~twice as many member
lookups, because we need to check if a `__get__` attribute exists on
accessed members.

A brief analysis on `tomllib` shows that we now call `Type::call` 1780
times, compared to 612 calls before.

## Limitations

* Data descriptors are not yet supported, i.e. we do not infer correct
types for descriptor attribute accesses in `Store` context and do not
check writes to descriptor attributes. I felt like this was something
that could be split out as a follow-up without risking a major
architectural change.
* We currently distinguish between `Type::member` (with descriptor
protocol) and `Type::static_member` (without descriptor protocol). The
former corresponds to `obj.attr`, the latter corresponds to
`getattr_static(obj, "attr")`. However, to model some details correctly,
we would also need to distinguish between a static member lookup *with*
and *without* instance variables. The lookup without instance variables
corresponds to `find_name_in_mro`
[here](https://docs.python.org/3/howto/descriptor.html#invocation-from-an-instance).
We currently approximate both using `member_static`, which leads to two
open TODOs. Changing this would be a larger refactoring of
`Type::own_instance_member`, so I chose to leave it out of this PR.

## Test Plan

* New `call/methods.md` test suite for method calls
* New tests in `descriptor_protocol.md`
* New `call/getattr_static.md` test suite for `inspect.getattr_static`
* Various updated tests
2025-02-20 23:22:26 +01:00
David Peter 8198668fc3
[red-knot] MDTest: Use custom class names instead of builtins (#16269)
## Summary

Follow up on the discussion
[here](https://github.com/astral-sh/ruff/pull/16121#discussion_r1962973298).
Replace builtin classes with custom placeholder names, which should
hopefully make the tests a bit easier to understand.

I carefully renamed things one after the other, to make sure that there
is no functional change in the tests.
2025-02-20 12:25:55 +00:00
Douglas Creager cfc6941d5c
[red-knot] Resolve references in eager nested scopes eagerly (#16079)
We now resolve references in "eager" scopes correctly — using the
bindings and declarations that are visible at the point where the eager
scope is created, not the "public" type of the symbol (typically the
bindings visible at the end of the scope).

---------

Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
2025-02-19 10:22:30 -05:00
Andrew Gallant 3ea32e2cdd red_knot_python_semantic: improve diagnostic message for "invalid argument type"
This uses the refactoring and support for secondary diagnostic messages
to improve the diagnostic for "invalid argument type." The main
improvement here is that we show where the function being called is
defined, and annotate the span corresponding to the invalid parameter.
2025-02-19 08:24:19 -05:00
David Peter 877c1066d3
[red-knot] Update tests for attributes inferred from parameters (#16208)
## Summary

Update description and remove TODOs from out `attributes.md` test suite
to reflect our current intentions.

closes https://github.com/astral-sh/ruff/issues/15960
2025-02-18 22:43:11 +01:00
Carl Meyer 00b022d472
[red-knot] update TODO comment in mdtest (#16242)
This comment gave wrong/misleading info about the reason for the wrong
output, just updating it to be correct to avoid confusing our future
selves.
2025-02-18 20:52:17 +00:00