## Summary
Add the ability to detect instance attribute assignments in class
methods that are generic.
This does not address the code duplication mentioned in #16928. I can
open a ticket for this after this has been merged.
closes#16928
## Test Plan
Added regression test.
## Summary
@sharkdp and I realised in our 1:1 this morning that our control flow
for `assert` statements isn't quite accurate at the moment. Namely, for
something like this:
```py
def _(x: int | None):
assert x is None, reveal_type(x)
```
we currently reveal `None` for `x` here, but this is incorrect. In
actual fact, the `msg` expression of an `assert` statement (the
expression after the comma) will only be evaluated if the test (`x is
None`) evaluates to `False`. As such, we should be adding a constraint
of `~None` to `x` in the `msg` expression, which should simplify the
inferred type of `x` to `int` in that context (`(int | None) & ~None` ->
`int`).
## Test Plan
Mdtests added.
---------
Co-authored-by: David Peter <mail@david-peter.de>
## Summary
We were previously recording wrong reachability constraints for negative
branches. Instead of `[cond] AND (NOT [True])` below, we were recording
`[cond] AND (NOT ([cond] AND [True]))`, i.e. we were negating not just
the last predicate, but the `AND`-ed reachability constraint from last
clause. With this fix, we now record the correct constraints for the
example from #17723:
```py
def _(cond: bool):
if cond:
# reachability: [cond]
if True:
# reachability: [cond] AND [True]
pass
else:
# reachability: [cond] AND (NOT [True])
x
```
closes#17723
## Test Plan
* Regression test.
* Verified the ecosystem changes
We are currently representing type variables using a `KnownInstance`
variant, which wraps a `TypeVarInstance` that contains the information
about the typevar (name, bounds, constraints, default type). We were
previously only constructing that type for PEP 695 typevars. This PR
constructs that type for legacy typevars as well.
It also detects functions that are generic because they use legacy
typevars in their parameter list. With the existing logic for inferring
specializations of function calls (#17301), that means that we are
correctly detecting that the definition of `reveal_type` in the typeshed
is generic, and inferring the correct specialization of `_T` for each
call site.
This does not yet handle legacy generic classes; that will come in a
follow-on PR.
Summary
--
This PR extends semantic syntax error detection to red-knot. The main
changes here are:
1. Adding `SemanticSyntaxChecker` and `Vec<SemanticSyntaxError>` fields
to the `SemanticIndexBuilder`
2. Calling `SemanticSyntaxChecker::visit_stmt` and `visit_expr` in the
`SemanticIndexBuilder`'s `visit_stmt` and `visit_expr` methods
3. Implementing `SemanticSyntaxContext` for `SemanticIndexBuilder`
4. Adding new mdtests to test the context implementation and show
diagnostics
(3) is definitely the trickiest and required (I think) a minor addition
to the `SemanticIndexBuilder`. I tried to look around for existing code
performing the necessary checks, but I definitely could have missed
something or misused the existing code even when I found it.
There's still one TODO around `global` statement handling. I don't think
there's an existing way to look this up, but I'm happy to work on that
here or in a separate PR. This currently only affects detection of one
error (`LoadBeforeGlobalDeclaration` or
[PLE0118](https://docs.astral.sh/ruff/rules/load-before-global-declaration/)
in ruff), so it's not too big of a problem even if we leave the TODO.
Test Plan
--
New mdtests, as well as new errors for existing mdtests
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
This PR is a follow-up to #16852.
Instance variables bound in comprehensions are recorded, allowing type
inference to work correctly.
This required adding support for unpacking in comprehension which
resolves https://github.com/astral-sh/ruff/issues/15369.
## Test Plan
One TODO in `mdtest/attributes.md` is now resolved, and some new test
cases are added.
---------
Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
## Summary
Fixes#17147.
This was landed in #17149 and then reverted in #17335 because it caused
cycle panics in checking pybind11. #17456 fixed the cause of that panic.
## Test Plan
Add new narrow/assert.md test file
Co-authored-by: Matthew Mckee <matthewmckee04@yahoo.co.uk>
## Summary
Part of #15383, this PR adds support for overloaded callables.
Typing spec: https://typing.python.org/en/latest/spec/overload.html
Specifically, it does the following:
1. Update the `FunctionType::signature` method to return signatures from
a possibly overloaded callable using a new `FunctionSignature` enum
2. Update `CallableType` to accommodate overloaded callable by updating
the inner type to `Box<[Signature]>`
3. Update the relation methods on `CallableType` with logic specific to
overloads
4. Update the display of callable type to display a list of signatures
enclosed by parenthesis
5. Update `CallableTypeOf` special form to recognize overloaded callable
6. Update subtyping, assignability and fully static check to account for
callables (equivalence is planned to be done as a follow-up)
For (2), it is required to be done in this PR because otherwise I'd need
to add some workaround for `into_callable_type` and I though it would be
best to include it in here.
For (2), another possible design would be convert `CallableType` in an
enum with two variants `CallableType::Single` and
`CallableType::Overload` but I decided to go with `Box<[Signature]>` for
now to (a) mirror it to be equivalent to `overload` field on
`CallableSignature` and (b) to avoid any refactor in this PR. This could
be done in a follow-up to better split the two kind of callables.
### Design
There were two main candidates on how to represent the overloaded
definition:
1. To include it in the existing infrastructure which is what this PR is
doing by recognizing all the signatures within the
`FunctionType::signature` method
2. To create a new `Overload` type variant
<details><summary>For context, this is what I had in mind with the new
type variant:</summary>
<p>
```rs
pub enum Type {
FunctionLiteral(FunctionType),
Overload(OverloadType),
BoundMethod(BoundMethodType),
...
}
pub struct OverloadType {
// FunctionLiteral or BoundMethod
overloads: Box<[Type]>,
// FunctionLiteral or BoundMethod
implementation: Option<Type>
}
pub struct BoundMethodType {
kind: BoundMethodKind,
self_instance: Type,
}
pub enum BoundMethodKind {
Function(FunctionType),
Overload(OverloadType),
}
```
</p>
</details>
The main reasons to choose (1) are the simplicity in the implementation,
reusing the existing infrastructure, avoiding any complications that the
new type variant has specifically around the different variants between
function and methods which would require the overload type to use `Type`
instead.
### Implementation
The core logic is how to collect all the overloaded functions. The way
this is done in this PR is by recording a **use** on the `Identifier`
node that represents the function name in the use-def map. This is then
used to fetch the previous symbol using the same name. This way the
signatures are going to be propagated from top to bottom (from first
overload to the final overload or the implementation) with each function
/ method. For example:
```py
from typing import overload
@overload
def foo(x: int) -> int: ...
@overload
def foo(x: str) -> str: ...
def foo(x: int | str) -> int | str:
return x
```
Here, each definition of `foo` knows about all the signatures that comes
before itself. So, the first overload would only see itself, the second
would see the first and itself and so on until the implementation or the
final overload.
This approach required some updates specifically recognizing
`Identifier` node to record the function use because it doesn't use
`ExprName`.
## Test Plan
Update existing test cases which were limited by the overload support
and add test cases for the following cases:
* Valid overloads as functions, methods, generics, version specific
* Invalid overloads as stated in
https://typing.python.org/en/latest/spec/overload.html#invalid-overload-definitions
(implementation will be done in a follow-up)
* Various relation: fully static, subtyping, and assignability (others
in a follow-up)
## Ecosystem changes
_WIP_
After going through the ecosystem changes (there are a lot!), here's
what I've found:
We need assignability check between a callable type and a class literal
because a lot of builtins are defined as classes in typeshed whose
constructor method is overloaded e.g., `map`, `sorted`, `list.sort`,
`max`, `min` with the `key` parameter, `collections.abc.defaultdict`,
etc. (https://github.com/astral-sh/ruff/issues/17343). This makes up
most of the ecosystem diff **roughly 70 diagnostics**. For example:
```py
from collections import defaultdict
# red-knot: No overload of bound method `__init__` matches arguments [lint:no-matching-overload]
defaultdict(int)
# red-knot: No overload of bound method `__init__` matches arguments [lint:no-matching-overload]
defaultdict(list)
class Foo:
def __init__(self, x: int):
self.x = x
# red-knot: No overload of function `__new__` matches arguments [lint:no-matching-overload]
map(Foo, ["a", "b", "c"])
```
Duplicate diagnostics in unpacking
(https://github.com/astral-sh/ruff/issues/16514) has **~16
diagnostics**.
Support for the `callable` builtin which requires `TypeIs` support. This
is **5 diagnostics**. For example:
```py
from typing import Any
def _(x: Any | None) -> None:
if callable(x):
# red-knot: `Any | None`
# Pyright: `(...) -> object`
# mypy: `Any`
# pyrefly: `(...) -> object`
reveal_type(x)
```
Narrowing on `assert` which has **11 diagnostics**. This is being worked
on in https://github.com/astral-sh/ruff/pull/17345. For example:
```py
import re
match = re.search("", "")
assert match
match.group() # error: [possibly-unbound-attribute]
```
Others:
* `Self`: 2
* Type aliases: 6
* Generics: 3
* Protocols: 13
* Unpacking in comprehension: 1
(https://github.com/astral-sh/ruff/pull/17396)
## Performance
Refer to
https://github.com/astral-sh/ruff/pull/17366#issuecomment-2814053046.
## Summary
Add more narrowing analysis for match statements:
* add narrowing constraints from guard expressions
* add negated constraints from previous predicates and guards to
subsequent cases
This PR doesn't address that guards can mutate your subject, and so
theoretically invalidate some of these narrowing constraints that you've
previously accumulated. Some prior art on this issue [here][mutable
guards].
[mutable guards]:
https://www.irif.fr/~scherer/research/mutable-patterns/mutable-patterns-mlworkshop2024-abstract.pdf
## Test Plan
Add some new tests, and update some existing ones
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Similar to what we did for `unresolved-reference` and
`unresolved-attribute`, we now also silence `unresolved-import`
diagnostics if the corresponding `import` statement is unreachable.
This addresses the (already closed) issue #17049.
## Test Plan
Adapted Markdown tests.
## Summary
Basically just repeat the same thing that we did for
`unresolved-reference`, but now for attribute expressions.
We now also handle the case where the unresolved attribute (or the
unresolved reference) diagnostic originates from a stringified type
annotation.
And I made the evaluation of reachability constraints lazy (will only be
evaluated right before we are about to emit a diagnostic).
## Test Plan
New Markdown tests for stringified annotations.
I merged #17149 without checking the ecosystem results, and it still
caused a cycle panic in pybind11. Reverting for now until I fix that, so
we don't lose the ecosystem signal on other PRs.
## Summary
Track the reachability of nested scopes within their parent scopes. We
use this as an additional requirement for emitting
`unresolved-reference` diagnostics (and in the future,
`unresolved-attribute` and `unresolved-import`). This means that we only
emit `unresolved-reference` for a given use of a symbol if the use
itself is reachable (within its own scope), *and if the scope itself is
reachable*. For example, no diagnostic should be emitted for the use of
`x` here:
```py
if False:
x = 1
def f():
print(x) # this use of `x` is reachable inside the `f` scope,
# but the whole `f` scope is not reachable.
```
There are probably more fine-grained ways of solving this problem, but
they require a more sophisticated understanding of nested scopes (see
#15777, in particular
https://github.com/astral-sh/ruff/issues/15777#issuecomment-2788950267).
But it doesn't seem completely unreasonable to silence *this specific
kind of error* in unreachable scopes.
## Test Plan
Observed changes in reachability tests and ecosystem.
## Summary
This implements a new approach to silencing `unresolved-reference`
diagnostics by keeping track of the reachability of each use of a
symbol. The changes merged in
https://github.com/astral-sh/ruff/pull/17169 are still needed for the
"Use of variable in nested function" test case, but that could also be
solved in another way eventually (see
https://github.com/astral-sh/ruff/issues/15777). We can use the same
technique to silence `unresolved-import` and `unresolved-attribute`
false-positives, but I think this could be merged in isolation.
## Test Plan
New Markdown tests, ecosystem tests
<!--
Thank you for contributing to Ruff! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title?
- Does this pull request include references to any relevant issues?
-->
## Summary
I decided to disable the new
[`needless_continue`](https://rust-lang.github.io/rust-clippy/master/index.html#needless_continue)
rule because I often found the explicit `continue` more readable over an
empty block or having to invert the condition of an other branch.
## Test Plan
`cargo test`
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
This PR refactors the common logic for unpacking in assignment, for loops, and with items.
## Test Plan
Make sure existing tests pass.
---------
Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
## 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`.
## 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>
## 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.
## 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>
Summary
--
Detects duplicate type parameter names in function definitions, class
definitions, and type alias statements.
I also boxed the `type_params` field on `StmtTypeAlias` to make it
easier to
`match` with functions and classes. (That's the reason for the red-knot
code
owner review requests, sorry!)
Test Plan
--
New `ruff_python_syntax_errors` unit tests.
Fixes#11119.
## 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>
## 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>
We currently keep two separate pieces of state regarding the current
loop on `SemanticIndexBuilder`. One is an enum simply reflecting whether
we are currently inside a loop, and the other is the saved flow states
for `break` statements found in the current loop.
For adding loopy control flow, I'll need to add some additional loop
state (`continue` states, for example). Prepare for this by
consolidating our existing loop state into a single struct and
simplifying the API for pushing and popping a loop.
This is purely a refactor, so tests are not changed.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
In https://github.com/astral-sh/ruff/pull/16306#discussion_r1966290700,
@carljm pointed out that #16306 introduced a terminology problem, with
too many things called a "constraint". This is a follow-up PR that
renames `Constraint` to `Predicate` to hopefully clear things up a bit.
So now we have that:
- a _predicate_ is a Python expression that might influence type
inference
- a _narrowing constraint_ is a list of predicates that constraint the
type of a binding that is visible at a use
- a _visibility constraint_ is a ternary formula of predicates that
define whether a binding is visible or a statement is reachable
This is a pure renaming, with no behavioral changes.
This PR adds an implementation of [association
lists](https://en.wikipedia.org/wiki/Association_list), and uses them to
replace the previous `BitSet`/`SmallVec` representation for narrowing
constraints.
An association list is a linked list of key/value pairs. We additionally
guarantee that the elements of an association list are sorted (by their
keys), and that they do not contain any entries with duplicate keys.
Association lists have fallen out of favor in recent decades, since you
often need operations that are inefficient on them. In particular,
looking up a random element by index is O(n), just like a linked list;
and looking up an element by key is also O(n), since you must do a
linear scan of the list to find the matching element. Luckily we don't
need either of those operations for narrowing constraints!
The typical implementation also suffers from poor cache locality and
high memory allocation overhead, since individual list cells are
typically allocated separately from the heap. We solve that last problem
by storing the cells of an association list in an `IndexVec` arena.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Two related changes. For context:
1. We were maintaining two separate arenas of `Constraint`s in each
use-def map. One was used for narrowing constraints, and the other for
visibility constraints. The visibility constraint arena was interned,
ensuring that we always used the same ID for any particular
`Constraint`. The narrowing constraint arena was not interned.
2. The TDD code relies on _all_ TDD nodes being interned and reduced.
This is an important requirement for TDDs to be a canonical form, which
allows us to use a single int comparison to test for "always true/false"
and to compare two TDDs for equivalence. But we also need to support an
individual `Constraint` having multiple values in a TDD evaluation (e.g.
to handle a `while` condition having different values the first time
it's evaluated vs later times). Previously, we handled that by
introducing a "copy" number, which was only there as a disambiguator, to
allow an interned, deduplicated constraint ID to appear in the TDD
formula multiple times.
A better way to handle (2) is to not intern the constraints in the
visibility constraint arena! The caller now gets to decide: if they add
a `Constraint` to the arena more than once, they get distinct
`ScopedConstraintId`s — which the TDD code will treat as distinct
variables, allowing them to take on different values in the ternary
function.
With that in place, we can then consolidate on a single (non-interned)
arena, which is shared for both narrowing and visibility constraints.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
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>
This is an alternative implementation to #15848.
## Summary
This PR adds support for re-export conventions for imports for stub
files.
**How does this work?**
* Add a new flag on the `Import` and `ImportFrom` definitions to
indicate whether they're being exported or not
* Add a new enum to indicate whether the symbol lookup is happening
within the same file or is being queried from another file (e.g., an
import statement)
* When a `Symbol` is being queried, we'll skip the definitions that are
(a) coming from a stub file (b) external lookup and (c) check the
re-export flag on the definition
This implementation does not yet support `__all__` and `*` imports as
both are features that needs to be implemented independently.
closes: #14099closes: #15476
## Test Plan
Add test cases, update existing ones if required.
## Summary
* Support assignments to attributes in more cases:
- assignments in `for` loops
- in unpacking assignments
* Add test for multi-target assignments
* Add tests for all other possible assignments to attributes that could
possibly occur (in decreasing order of likeliness):
- augmented attribute assignments
- attribute assignments in `with` statements
- attribute assignments in comprehensions
- Note: assignments to attributes in named expressions are not
syntactically allowed
closes#15962
## Test Plan
New Markdown tests
This example from @sharkdp shows how terminal statements can appear in
statically known branches:
https://github.com/astral-sh/ruff/pull/15676#issuecomment-2618809716
```py
def _(cond: bool):
x = "a"
if cond:
x = "b"
if True:
return
reveal_type(x) # revealed: "a", "b"; should be "a"
```
We now use visibility constraints to track reachability, which allows us
to model this correctly. There are two related changes as a result:
- New bindings are not assumed to be visible; they inherit the current
"scope start" visibility, which effectively means that new bindings are
visible if/when the current flow is reachable
- When simplifying visibility constraints after branching control flow,
we only simplify if none of the intervening branches included a terminal
statement. That is, earlier unaffected bindings are only _actually_
unaffected if all branches make it to the merge point.
This extracts some pure refactoring noise from
https://github.com/astral-sh/ruff/pull/15861. This changes the API for
creating and evaluating visibility constraints, but does not change how
they are respresented internally. There should be no behavioral or
performance changes in this PR.
Changes:
- Hide the internal representation isn't changed, so that we can make
changes to it in #15861.
- Add a separate builder type for visibility constraints. (With TDDs, we
will have some additional builder state that we can throw away once
we're done constructing.)
- Remove a layer of helper methods from `UseDefMapBuilder`, making
`SemanticIndexBuilder` responsible for constructing whatever visibility
constraints it needs.
## Summary
Add support for implicitly-defined instance attributes, i.e. support
type inference for cases like this:
```py
class C:
def __init__(self) -> None:
self.x: int = 1
self.y = None
reveal_type(C().x) # int
reveal_type(C().y) # Unknown | None
```
## Benchmarks
Codspeed reports no change in a cold-cache benchmark, and a -1%
regression in the incremental benchmark. On `black`'s `src` folder, I
don't see a statistically significant difference between the branches:
| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
|:---|---:|---:|---:|---:|
| `./red_knot_main check --project /home/shark/black/src` | 133.7 ± 9.5 | 126.7 | 164.7 | 1.01 ± 0.08 |
| `./red_knot_feature check --project /home/shark/black/src` | 132.2 ± 5.1 | 118.1 | 140.9 | 1.00 |
## Test Plan
Updated and new Markdown tests
This mimics a simplification we have on the OR side, where we simplify
`A ∨ !A` to true. This requires changes to how we add `while` statements
to the semantic index, since we now need distinct
`VisibilityConstraint`s if we need to model evaluating a `Constraint`
multiple times at different points in the execution of the program.
`FlowSnapshot` now tracks a `reachable` bool, which indicates whether we
have encountered a terminal statement on that control flow path. When
merging flow states together, we skip any that have been marked
unreachable. This ensures that bindings that can only be reached through
unreachable paths are not considered visible.
## Test Plan
The new mdtests failed (with incorrect `reveal_type` results, and
spurious `possibly-unresolved-reference` errors) before adding the new
visibility constraints.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
We now support class patterns in a match statement, adding a narrowing
constraint that within the body of that match arm, we can assume that
the subject is an instance of that class.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
The test expression in an `elif` clause is evaluated whether or not we
take the branch. Our control flow model for if/elif chains failed to
reflect this, causing wrong inference in cases where an assignment
expression occurs inside an `elif` test expression. Our "no branch taken
yet" snapshot (which is the starting state for every new elif branch)
can't simply be the pre-if state, it must be updated after visiting each
test expression.
Once we do this, it also means we no longer need to track a vector of
narrowing constraints to reapply for each new branch, since our "branch
not taken" state (which is the initial state for each branch) is
continuously updated to include the negative narrowing constraints of
all previous branches.
Fixes#15033.
## Test Plan
Added mdtests.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
