## Summary
`typing_extensions` has a `>=3.13` re-export for the `typing.NoDefault`
singleton, but not for `typing._NoDefaultType`. This causes problems as
soon as we understand `sys.version_info` branches, so we explicity
switch to `typing._NoDefaultType` for Python 3.13 and later.
This is a part of #14759 that I thought might make sense to break out
and merge in isolation.
## Test Plan
New test that will become more meaningful with #12700
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
- Instead of seven (more or less similar) `setup_db` functions, use just
one in a single central place.
- For every test that needs customization beyond that, offer a
`TestDbBuilder` that can control the Python target version, custom
typeshed, and pre-existing files.
The main motivation for this is that we're soon going to need
customization of the Python version, and I didn't feel like adding this
to each of the existing `setup_db` functions.
## Summary
This changeset contains various improvements concerning non-fully-static
types and their relationships:
- Make sure that non-fully-static types do not participate in
equivalence or subtyping.
- Clarify what `Type::is_equivalent_to` actually implements.
- Introduce `Type::is_fully_static`
- New tests making sure that multiple `Any`/`Unknown`s inside unions and
intersections are collapsed.
closes#14524
## Test Plan
- Added new unit tests for union and intersection builder
- Added new unit tests for `Type::is_equivalent_to`
- Added new unit tests for `Type::is_subtype_of`
- Added new property test making sure that non-fully-static types do not
participate in subtyping
We already had a representation for the Any type, which we would use
e.g. for expressions without type annotations. We now recognize
`typing.Any` as a way to refer to this type explicitly. Like other
special forms, this is tracked correctly through aliasing, and isn't
confused with local definitions that happen to have the same name.
Closes#14544
## Summary
Minor change that uses two plain classes `A` and `B` instead of
`typing.Sized` and `typing.Hashable`.
The motivation is twofold: I remember that I was confused when I first
saw this test. Was there anything specific to `Sized` and `Hashable`
that was relevant here? (there is, these classes are not overlapping;
and you can build a proper intersection from them; but that's true for
almost all non-builtin classes).
I now ran into another problem while working on #14758: `Sized` and
`Hashable` are protocols that we don't fully understand yet. This
causing some trouble when trying to infer whether these are fully-static
types or not.
## Summary
This PR adds a new `property_tests` module with quickcheck-based tests
that verify certain properties of types. The following properties are
currently checked:
* `is_equivalent_to`:
* is reflexive: `T` is equivalent to itself
* `is_subtype_of`:
* is reflexive: `T` is a subtype of `T`
* is antisymmetric: if `S <: T` and `T <: S`, then `S` is equivalent to
`T`
* is transitive: `S <: T` & `T <: U` => `S <: U`
* `is_disjoint_from`:
* is irreflexive: `T` is not disjoint from `T`
* is symmetric: `S` disjoint from `T` => `T` disjoint from `S`
* `is_assignable_to`:
* is reflexive
* `negate`:
* is an involution: `T.negate().negate()` is equivalent to `T`
There are also some tests that validate higher-level properties like:
* `S <: T` implies that `S` is not disjoint from `T`
* `S <: T` implies that `S` is assignable to `T`
* A singleton type must also be single-valued
These tests found a few bugs so far:
- #14177
- #14195
- #14196
- #14210
- #14731
Some additional notes:
- Quickcheck-based property tests are non-deterministic and finding
counter-examples might take an arbitrary long time. This makes them bad
candidates for running in CI (for every PR). We can think of running
them in a cron-job way from time to time, similar to fuzzing. But for
now, it's only possible to run them locally (see instructions in source
code).
- Some tests currently find false positive "counterexamples" because our
understanding of equivalence of types is not yet complete. We do not
understand that `int | str` is the same as `str | int`, for example.
These tests are in a separate `property_tests::flaky` module.
- Properties can not be formulated in every way possible, due to the
fact that `is_disjoint_from` and `is_subtype_of` can produce false
negative answers.
- The current shrinking implementation is very naive, which leads to
counterexamples that are very long (`str & Any & ~tuple[Any] &
~tuple[Unknown] & ~Literal[""] & ~Literal["a"] | str & int & ~tuple[Any]
& ~tuple[Unknown]`), requiring the developer to simplify manually. It
has not been a major issue so far, but there is a comment in the code
how this can be improved.
- The tests are currently implemented using a macro. This is a single
commit on top which can easily be reverted, if we prefer the plain code
instead. With the macro:
```rs
// `S <: T` implies that `S` can be assigned to `T`.
type_property_test!(
subtype_of_implies_assignable_to, db,
forall types s, t. s.is_subtype_of(db, t) => s.is_assignable_to(db, t)
);
```
without the macro:
```rs
/// `S <: T` implies that `S` can be assigned to `T`.
#[quickcheck]
fn subtype_of_implies_assignable_to(s: Ty, t: Ty) -> bool {
let db = get_cached_db();
let s = s.into_type(&db);
let t = t.into_type(&db);
!s.is_subtype_of(&*db, t) || s.is_assignable_to(&*db, t)
}
```
## Test Plan
```bash
while cargo test --release -p red_knot_python_semantic --features property_tests types::property_tests; do :; done
```
## Summary
`KnownInstance::instance_fallback` may return instances of supertypes.
For example, it returns an instance of `_SpecialForm` for `Literal`.
This means it can't be used on the right-hand side of `is_subtype_of`
relationships, because it might lead to false positives.
I can lead to false negatives on the left hand side of `is_subtype_of`,
but this is at least a known limitation. False negatives are fine for
most applications, but false positives can lead to wrong results in
intersection-simplification, for example.
closes#14731
## Test Plan
Added regression test
## Summary
Simplify tuples containing `Never` to `Never`:
```py
from typing import Never
def never() -> Never: ...
reveal_type((1, never(), "foo")) # revealed: Never
```
I should note that mypy and pyright do *not* perform this
simplification. I don't know why.
There is [only one
place](5137fcc9c8/crates/red_knot_python_semantic/src/types/infer.rs (L1477-L1484))
where we use `TupleType::new` directly (instead of `Type::tuple`, which
changes behavior here). This appears when creating `TypeVar`
constraints, and it looks to me like it should stay this way, because
we're using `TupleType` to store a list of constraints there, instead of
an actual type. We also store `tuple[constraint1, constraint2, …]` as
the type for the `constraint1, constraint2, …` tuple expression. This
would mean that we infer a type of `tuple[str, Never]` for the following
type variable constraints, without simplifying it to `Never`. This seems
like a weird edge case that's maybe not worth looking further into?!
```py
from typing import Never
# vvvvvvvvvv
def f[T: (str, Never)](x: T):
pass
```
## Test Plan
- Added a new unit test. Did not add additional Markdown tests as that
seems superfluous.
- Tested the example above using red knot, mypy, pyright.
- Verified that this allows us to remove `contains_never` from the
property tests
(https://github.com/astral-sh/ruff/pull/14178#discussion_r1866473192)
Resolves https://github.com/astral-sh/ruff/issues/14547 by delegating
narrowing to `E` for `bool(E)` where `E` is some expression.
This change does not include other builtin class constructors which
should also work in this position, like `int(..)` or `float(..)`, as the
original issue does not mention these. It should be easy enough to add
checks for these as well if we want to.
I don't see a lot of markdown tests for malformed input, maybe there's a
better place for the no args and too many args cases to go?
I did see after the fact that it looks like this task was intended for a
new hire.. my apologies. I got here from
https://github.com/astral-sh/ruff/issues/13694, which is marked
help-wanted.
---------
Co-authored-by: David Peter <mail@david-peter.de>
## Summary
Closes: https://github.com/astral-sh/ruff/issues/14593
The final type of a variable after if-statement without explicit else
branch should be similar to having an explicit else branch.
## Test Plan
Originally failed test cases from the bug are added.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
`bool()` is equal to `False`, and we infer `Literal[False]` for it. Which
means that the test here will fail as soon as we treat the body of
this `if` as unreachable.
## Summary
Fix panics related to expressions without inferred types in invalid
syntax examples like:
```py
x: f"Literal[{1 + 2}]" = 3
```
where the `1 + 2` expression (and its sub-expressions) inside the
annotation did not have an inferred type.
## Test Plan
Added new corpus test.
## Summary
This is about the easiest patch that I can think of. It has a drawback
in that there is no real guarantee this won't happen again. I think this
might be acceptable, given that all of this is a temporary thing.
And we also add a new CI job to prevent regressions like this in the
future.
For the record though, I'm listing alternative approaches I thought of:
- We could get rid of the debug/release distinction and just add `@Todo`
type metadata everywhere. This has possible affects on runtime. The main
reason I didn't follow through with this is that the size of `Type`
increases. We would either have to adapt the `assert_eq_size!` test or
get rid of it. Even if we add messages everywhere and get rid of the
file-and-line-variant in the enum, it's not enough to get back to the
current release-mode size of `Type`.
- We could generally discard `@Todo` meta information when using it in
tests. I think this would be a huge drawback. I like that we can have
the actual messages in the mdtest. And make sure we get the expected
`@Todo` type, not just any `@Todo`. It's also helpful when debugging
tests.
closes#14594
## Test Plan
```rs
cargo nextest run --release
```
Fix#14558
## Summary
- Add `typing.NoReturn` and `typing.Never` to known instances and infer
them as `Type::Never`
- Add `is_assignable_to` cases for `Type::Never`
I skipped emitting diagnostic for when a function is annotated as
`NoReturn` but it actually returns.
## Test Plan
Added tests from
https://github.com/python/typing/blob/main/conformance/tests/specialtypes_never.py
except from generics and checking if the return value of the function
and the annotations match.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Closes#14588
```py
x: Literal[42, "hello"] = 42 if bool_instance() else "hello"
reveal_type(x) # revealed: Literal[42] | Literal["hello"]
_ = ... if isinstance(x, str) else ...
# The `isinstance` test incorrectly narrows the type of `x`.
# As a result, `x` is revealed as Literal["hello"], but it should remain Literal[42, "hello"].
reveal_type(x) # revealed: Literal["hello"]
```
## Test Plan
mdtest included!
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
This fix addresses panics related to invalid syntax like the following
where a `break` statement is used in a nested definition inside a
loop:
```py
while True:
def b():
x: int
break
```
closes#14342
## Test Plan
* New corpus regression tests.
* New unit test to make sure we handle nested while loops correctly.
This test is passing on `main`, but can easily fail if the
`is_inside_loop` state isn't properly saved/restored.
## Summary
Add support for (non-generic) type aliases. The main motivation behind
this was to get rid of panics involving expressions in (generic) type
aliases. But it turned out the best way to fix it was to implement
(partial) support for type aliases.
```py
type IntOrStr = int | str
reveal_type(IntOrStr) # revealed: typing.TypeAliasType
reveal_type(IntOrStr.__name__) # revealed: Literal["IntOrStr"]
x: IntOrStr = 1
reveal_type(x) # revealed: Literal[1]
def f() -> None:
reveal_type(x) # revealed: int | str
```
## Test Plan
- Updated corpus test allow list to reflect that we don't panic anymore.
- Added Markdown-based test for type aliases (`type_alias.md`)
## Summary
Fixes a panic related to sub-expressions of `typing.Union` where we fail
to store a type for the `int, str` tuple-expression in code like this:
```
x: Union[int, str] = 1
```
relates to [my
comment](https://github.com/astral-sh/ruff/pull/14499#discussion_r1851794467)
on #14499.
## Test Plan
New corpus test
## Summary
Adds meta information to `Type::Todo`, allowing developers to easily
trace back the origin of a particular `@Todo` type they encounter.
Instead of `Type::Todo`, we now write either `type_todo!()` which
creates a `@Todo[path/to/source.rs:123]` type with file and line
information, or using `type_todo!("PEP 604 unions not supported")`,
which creates a variant with a custom message.
`Type::Todo` now contains a `TodoType` field. In release mode, this is
just a zero-sized struct, in order not to create any overhead. In debug
mode, this is an `enum` that contains the meta information.
`Type` implements `Copy`, which means that `TodoType` also needs to be
copyable. This limits the design space. We could intern `TodoType`, but
I discarded this option, as it would require us to have access to the
salsa DB everywhere we want to use `Type::Todo`. And it would have made
the macro invocations less ergonomic (requiring us to pass `db`).
So for now, the meta information is simply a `&'static str` / `u32` for
the file/line variant, or a `&'static str` for the custom message.
Anything involving a chain/backtrace of several `@Todo`s or similar is
therefore currently not implemented. Also because we currently don't see
any direct use cases for this, and because all of this will eventually
go away.
Note that the size of `Type` increases from 16 to 24 bytes, but only in
debug mode.
## Test Plan
- Observed the changes in Markdown tests.
- Added custom messages for all `Type::Todo`s that were revealed in the
tests
- Ran red knot in release and debug mode on the following Python file:
```py
def f(x: int) -> int:
reveal_type(x)
```
Prints `@Todo` in release mode and `@Todo(function parameter type)` in
debug mode.
Fix#14498
## Summary
This PR adds `typing.Union` support
## Test Plan
I created new tests in mdtest.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
closes#14279
### Limitations of the Current Implementation
#### Incorrect Error Propagation
In the current implementation of lexicographic comparisons, if the
result of an Eq operation is Ambiguous, the comparison stops
immediately, returning a bool instance. While this may yield correct
inferences, it fails to capture unsupported-operation errors that might
occur in subsequent comparisons.
```py
class A: ...
(int_instance(), A()) < (int_instance(), A()) # should error
```
#### Weak Inference in Specific Cases
> Example: `(int_instance(), "foo") == (int_instance(), "bar")`
> Current result: `bool`
> Expected result: `Literal[False]`
`Eq` and `NotEq` have unique behavior in lexicographic comparisons
compared to other operators. Specifically:
- For `Eq`, if any non-equal pair exists within the tuples being
compared, we can immediately conclude that the tuples are not equal.
- For `NotEq`, if any equal pair exists, we can conclude that the tuples
are unequal.
```py
a = (str_instance(), int_instance(), "foo")
reveal_type(a == a) # revealed: bool
reveal_type(a != a) # revealed: bool
b = (str_instance(), int_instance(), "bar")
reveal_type(a == b) # revealed: bool # should be Literal[False]
reveal_type(a != b) # revealed: bool # should be Literal[True]
```
#### Incorrect Support for Non-Boolean Rich Comparisons
In CPython, aside from `==` and `!=`, tuple comparisons return a
non-boolean result as-is. Tuples do not convert the value into `bool`.
Note: If all pairwise `==` comparisons between elements in the tuples
return Truthy, the comparison then considers the tuples' lengths.
Regardless of the return type of the dunder methods, the final result
can still be a boolean.
```py
from __future__ import annotations
class A:
def __eq__(self, o: object) -> str:
return "hello"
def __ne__(self, o: object) -> bytes:
return b"world"
def __lt__(self, o: A) -> float:
return 3.14
a = (A(), A())
reveal_type(a == a) # revealed: bool
reveal_type(a != a) # revealed: bool
reveal_type(a < a) # revealed: bool # should be: `float | Literal[False]`
```
### Key Changes
One of the major changes is that comparisons no longer end with a `bool`
result when a pairwise `Eq` result is `Ambiguous`. Instead, the function
attempts to infer all possible cases and unions the results. This
improvement allows for more robust type inference and better error
detection.
Additionally, as the function is now optimized for tuple comparisons,
the name has been changed from the more general
`infer_lexicographic_comparison` to `infer_tuple_rich_comparison`.
## Test Plan
mdtest included
## Summary
Previously, we panicked on expressions like `f"{v:{f'0.2f'}}"` because
we did not infer types for expressions nested inside format spec
elements.
## Test Plan
```
cargo nextest run -p red_knot_workspace -- --ignored linter_af linter_gz
```
## Summary
Add type narrowing for `type(x) is C` conditions (and `else` clauses of
`type(x) is not C` conditionals):
```py
if type(x) is A:
reveal_type(x) # revealed: A
else:
reveal_type(x) # revealed: A | B
```
closes: #14431, part of: #13694
## Test Plan
New Markdown-based tests.
## Summary
This patches up various missing paths where sub-expressions of type
annotations previously had no type attached. Examples include:
```py
tuple[int, str]
# ~~~~~~~~
type[MyClass]
# ~~~~~~~
Literal["foo"]
# ~~~~~
Literal["foo", Literal[1, 2]]
# ~~~~~~~~~~~~~
Literal[1, "a", random.illegal(sub[expr + ession])]
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
## Test Plan
```
cargo nextest run -p red_knot_workspace -- --ignored linter_af linter_gz
```
## Summary
This PR adds support for parsing and inferring types within string
annotations.
### Implementation (attempt 1)
This is preserved in
6217f48924.
The implementation here would separate the inference of string
annotations in the deferred query. This requires the following:
* Two ways of evaluating the deferred definitions - lazily and eagerly.
* An eager evaluation occurs right outside the definition query which in
this case would be in `binding_ty` and `declaration_ty`.
* A lazy evaluation occurs on demand like using the
`definition_expression_ty` to determine the function return type and
class bases.
* The above point means that when trying to get the binding type for a
variable in an annotated assignment, the definition query won't include
the type. So, it'll require going through the deferred query to get the
type.
This has the following limitations:
* Nested string annotations, although not necessarily a useful feature,
is difficult to implement unless we convert the implementation in an
infinite loop
* Partial string annotations require complex layout because inferring
the types for stringified and non-stringified parts of the annotation
are done in separate queries. This means we need to maintain additional
information
### Implementation (attempt 2)
This is the final diff in this PR.
The implementation here does the complete inference of string annotation
in the same definition query by maintaining certain state while trying
to infer different parts of an expression and take decisions
accordingly. These are:
* Allow names that are part of a string annotation to not exists in the
symbol table. For example, in `x: "Foo"`, if the "Foo" symbol is not
defined then it won't exists in the symbol table even though it's being
used. This is an invariant which is being allowed only for symbols in a
string annotation.
* Similarly, lookup name is updated to do the same and if the symbol
doesn't exists, then it's not bounded.
* Store the final type of a string annotation on the string expression
itself and not for any of the sub-expressions that are created after
parsing. This is because those sub-expressions won't exists in the
semantic index.
Design document:
https://www.notion.so/astral-sh/String-Annotations-12148797e1ca801197a9f146641e5b71?pvs=4Closes: #13796
## Test Plan
* Add various test cases in our markdown framework
* Run `red_knot` on LibCST (contains a lot of string annotations,
specifically
https://github.com/Instagram/LibCST/blob/main/libcst/matchers/_matcher_base.py),
FastAPI (good amount of annotated code including `typing.Literal`) and
compare against the `main` branch output
## Summary
Add a typed representation of function signatures (parameters and return
type) and infer it correctly from a function.
Convert existing usage of function return types to use the signature
representation.
This does not yet add inferred types for parameters within function body
scopes based on the annotations, but it should be easy to add as a next
step.
Part of #14161 and #13693.
## Test Plan
Added tests.
## Summary
This fixes several panics related to invalid assignment targets. All of
these led to some a crash, previously:
```py
(x.y := 1) # only name-expressions are valid targets of named expressions
([x, y] := [1, 2]) # same
(x, y): tuple[int, int] = (2, 3) # tuples are not valid targets for annotated assignments
(x, y) += 2 # tuples are not valid targets for augmented assignments
```
closes#14321closes#14322
## Test Plan
I symlinked four files from `crates/ruff_python_parser/resources` into
the red knot corpus, as they seemed like ideal test files for this exact
scenario. I think eventually, it might be a good idea to simply include *all*
invalid-syntax examples from the parser tests into red knots corpus (I believe
we're actually not too far from that goal). Or expand the scope of the corpus
test to this directory. Then we can get rid of these symlinks again.
## Summary
This avoids a panic inside `TypeInferenceBuilder::infer_type_parameters`
when encountering generic type aliases:
```py
type ListOrSet[T] = list[T] | set[T]
```
To fix this properly, we would have to treat type aliases as being their own
annotation scope [1]. The left hand side is a definition for the type parameter
`T` which is being used in the special annotation scope on the right hand side.
Similar to how it works for generic functions and classes.
[1] https://docs.python.org/3/reference/compound_stmts.html#generic-type-aliasescloses#14307
## Test Plan
Added new example to the corpus.
When we look up the types of class bases or keywords (`metaclass`), we
currently do this little dance: if there are type params, then look up
the type using `SemanticModel` in the type-params scope, if not, look up
the type directly in the definition's own scope, with support for
deferred types.
With inference of function parameter types, I'm now adding another case
of this same dance, so I'm motivated to make it a bit more ergonomic.
Add support to `definition_expression_ty` to handle any sub-expression
of a definition, whether it is in the definition's own scope or in a
type-params sub-scope.
Related to both #13693 and #14161.
## Summary
Use the memory address to uniquely identify AST nodes, instead of
relying on source range and kind. The latter fails for ASTs resulting
from invalid syntax examples. See #14313 for details.
Also results in a 1-2% speedup
(https://codspeed.io/astral-sh/ruff/runs/67349cf55f36b36baa211360)
closes#14313
## Review
Here are the places where we use `NodeKey` directly or indirectly (via
`ExpressionNodeKey` or `DefinitionNodeKey`):
```rs
// semantic_index.rs
pub(crate) struct SemanticIndex<'db> {
// [...]
/// Map expressions to their corresponding scope.
scopes_by_expression: FxHashMap<ExpressionNodeKey, FileScopeId>,
/// Map from a node creating a definition to its definition.
definitions_by_node: FxHashMap<DefinitionNodeKey, Definition<'db>>,
/// Map from a standalone expression to its [`Expression`] ingredient.
expressions_by_node: FxHashMap<ExpressionNodeKey, Expression<'db>>,
// [...]
}
// semantic_index/builder.rs
pub(super) struct SemanticIndexBuilder<'db> {
// [...]
scopes_by_expression: FxHashMap<ExpressionNodeKey, FileScopeId>,
definitions_by_node: FxHashMap<ExpressionNodeKey, Definition<'db>>,
expressions_by_node: FxHashMap<ExpressionNodeKey, Expression<'db>>,
}
// semantic_index/ast_ids.rs
pub(crate) struct AstIds {
/// Maps expressions to their expression id.
expressions_map: FxHashMap<ExpressionNodeKey, ScopedExpressionId>,
/// Maps expressions which "use" a symbol (that is, [`ast::ExprName`]) to a use id.
uses_map: FxHashMap<ExpressionNodeKey, ScopedUseId>,
}
pub(super) struct AstIdsBuilder {
expressions_map: FxHashMap<ExpressionNodeKey, ScopedExpressionId>,
uses_map: FxHashMap<ExpressionNodeKey, ScopedUseId>,
}
```
## Test Plan
Added two failing examples to the corpus.
## Summary
Fixes a failing debug assertion that triggers for the following code:
```py
match some_int:
case x:=2:
pass
```
closes#14305
## Test Plan
Added problematic code example to corpus.
## Summary
- Emit diagnostics when looking up (possibly) unbound attributes
- More explicit test assertions for unbound symbols
- Review remaining call sites of `Symbol::ignore_possibly_unbound`. Most
of them are something like `builtins_symbol(self.db,
"Ellipsis").ignore_possibly_unbound().unwrap_or(Type::Unknown)` which
look okay to me, unless we want to emit additional diagnostics. There is
one additional case in enum literal handling, which has a TODO comment
anyway.
part of #14022
## Test Plan
New MD tests for (possibly) unbound attributes.
## Summary
This adds a new diagnostic when possibly unbound symbols are imported.
The `TODO` comment had a question mark, do I'm not sure if this is
really something that we want.
This does not touch the un*declared* case, yet.
relates to: #14022
## Test Plan
Updated already existing tests with new diagnostics
## Summary
Apart from one small functional change, this is mostly a refactoring of
the `Symbol` API:
- Rename `as_type` to the more explicit `ignore_possibly_unbound`, no
functional change
- Remove `unwrap_or_unknown` in favor of the more explicit
`.ignore_possibly_unbound().unwrap_or(Type::Unknown)`, no functional
change
- Consistently call it "possibly unbound" (not "may be unbound")
- Rename `replace_unbound_with` to `or_fall_back_to` and properly handle
boundness of the fall back. This is the only functional change (did not
have any impact on existing tests).
relates to: #14022
## Test Plan
New unit tests for `Symbol::or_fall_back_to`
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Create definitions and infer types for PEP 695 type variables.
This just gives us the type of the type variable itself (the type of `T`
as a runtime object in the body of `def f[T](): ...`), with special
handling for its attributes `__name__`, `__bound__`, `__constraints__`,
and `__default__`. Mostly the support for these attributes exists
because it is easy to implement and allows testing that we are
internally representing the typevar correctly.
This PR doesn't yet have support for interpreting a typevar as a type
annotation, which is of course the primary use of a typevar. But the
information we store in the typevar's type in this PR gives us
everything we need to handle it correctly in a future PR when the
typevar appears in an annotation.
## Test Plan
Added mdtest.
## Summary
`Ty::BuiltinClassLiteral(…)` is a sub~~class~~type of
`Ty::BuiltinInstance("type")`, so it can't be disjoint from it.
## Test Plan
New `is_not_disjoint_from` test case
## Summary
Fix `Type::is_assignable_to` for union types on the left hand side (of
`.is_assignable_to`; or the right hand side of the `… = …` assignment):
`Literal[1, 2]` should be assignable to `int`.
## Test Plan
New unit tests that were previously failing.
## Summary
Minor fix to `Type::is_subtype_of` to make sure that Boolean literals
are subtypes of `int`, to match runtime semantics.
Found this while doing some property-testing experiments [1].
[1] https://github.com/astral-sh/ruff/pull/14178
## Test Plan
New unit test.
## Summary
Fixes#14114. I don't think I can really describe the problems with our
current architecture (and therefore the motivations for this PR) any
better than @carljm did in that issue, so I'll just copy it out here!
---
We currently represent "known instances" (e.g. special forms like
`typing.Literal`, which are an instance of `typing._SpecialForm`, but
need to be handled differently from other instances of
`typing._SpecialForm`) as an `InstanceType` with a `known` field that is
`Some(...)`.
This makes it easy to handle a known instance as if it were a regular
instance type (by ignoring the `known` field), and in some cases (e.g.
`Type::member`) that is correct and convenient. But in other cases (e.g.
`Type::is_equivalent_to`) it is not correct, and we currently have a bug
that we would consider the known-instance type of `typing.Literal` as
equivalent to the general instance type for `typing._SpecialForm`, and
we would fail to consider it a singleton type or a single-valued type
(even though it is both.)
An instance type with `known.is_some()` is semantically quite different
from an instance type with `known.is_none()`. The former is a singleton
type that represents exactly one runtime object; the latter is an open
type that represents many runtime objects, including instances of
unknown subclasses. It is too error-prone to represent these
very-different types as a single `Type` variant. We should instead
introduce a dedicated `Type::KnownInstance` variant and force ourselves
to handle these explicitly in all `Type` variant matches.
## Possible followups
There is still a little bit of awkwardness in our current design in some
places, in that we first infer the symbol `typing.Literal` as a
`_SpecialForm` instance, and then later convert that instance-type into
a known-instance-type. We could also use this `KnownInstanceType` enum
to account for other special runtime symbols such as `builtins.Ellipsis`
or `builtins.NotImplemented`.
I think these might be worth pursuing, but I didn't do them here as they
didn't seem essential right now, and I wanted to keep the diff
relatively minimal.
## Test Plan
`cargo test -p red_knot_python_semantic`. New unit tests added for
`Type::is_subtype_of`.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
This adds type inference for comparison expressions involving
intersection types.
For example:
```py
x = get_random_int()
if x != 42:
reveal_type(x == 42) # revealed: Literal[False]
reveal_type(x == 43) # bool
```
closes#13854
## Test Plan
New Markdown-based tests.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
- Get rid of `Symbol::unwrap_or` (unclear semantics, not needed anymore)
- Introduce `Type::call_dunder`
- Emit new diagnostic for possibly-unbound `__iter__` methods
- Better diagnostics for callables with possibly-unbound /
possibly-non-callable `__call__` methods
part of: #14022closes#14016
## Test Plan
- Updated test for iterables with possibly-unbound `__iter__` methods.
- New tests for callables
## Summary
- Adds basic support for `type[C]` as a red knot `Type`. Some things
might not be supported yet, like `type[Any]`.
- Adds type narrowing for `issubclass` checks.
closes#14117
## Test Plan
New Markdown-based tests
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
I mirrored some of the idioms that @AlexWaygood used in the MRO work.
Closes https://github.com/astral-sh/ruff/issues/14096.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Related to
https://github.com/astral-sh/ruff/pull/13979#discussion_r1828305790,
this PR removes the `current_unpack` state field from
`SemanticIndexBuilder` and passes the `Unpack` ingredient via the
`CurrentAssignment` -> `DefinitionNodeRef` conversion to finally store
it on `DefintionNodeKind`.
This involves updating the lifetime of `AnyParameterRef` (parameter to
`declare_parameter`) to use the `'db` lifetime. Currently, all AST nodes
stored on various enums are marked with `'a` lifetime but they're always
utilized using the `'db` lifetime.
This also removes the dedicated `'a` lifetime parameter on
`add_definition` which is currently being used in `DefinitionNodeRef`.
As mentioned, all AST nodes live through the `'db` lifetime so we can
remove the `'a` lifetime parameter from that method and use the `'db`
lifetime instead.
## Summary
- Store the expression type for annotations that are starred expressions
(see [discussion
here](https://github.com/astral-sh/ruff/pull/14091#discussion_r1828332857))
- Use `self.store_expression_type(…)` consistently throughout, as it
makes sure that no double-insertion errors occur.
closes#14115
## Test Plan
Added an invalid-syntax example to the corpus which leads to a panic on
`main`. Also added a Markdown test with a valid-syntax example that
would lead to a panic once we implement function parameter inference.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Adds more precise type inference for `… is …` and `… is not …` identity
checks in some limited cases where we statically know the answer to be
either `Literal[True]` or `Literal[False]`.
I found this helpful while working on type inference for comparisons
involving intersection types, but I'm not sure if this is at all useful
for real world code (where the answer is most probably *not* statically
known). Note that we already have *type narrowing* for identity tests.
So while we are already able to generate constraints for things like `if
x is None`, we can now — in some limited cases — make an even stronger
conclusion and infer that the test expression itself is `Literal[False]`
(branch never taken) or `Literal[True]` (branch always taken).
## Test Plan
New Markdown tests
Handling `Literal` type in annotations.
Resolves: #13672
## Implementation
Since Literals are not a fully defined type in typeshed. I used a trick
to figure out when a special form is a literal.
When we are inferring assignment types I am checking if the type of that
assignment was resolved to typing.SpecialForm and the name of the target
is `Literal` if that is the case then I am re creating a new instance
type and set the known instance field to `KnownInstance:Literal`.
**Why not defining a new type?**
From this [issue](https://github.com/python/typeshed/issues/6219) I
learned that we want to resolve members to SpecialMethod class. So if we
create a new instance here we can rely on the member resolving in that
already exists.
## Tests
https://typing.readthedocs.io/en/latest/spec/literal.html#equivalence-of-two-literals
Since the type of the value inside Literal is evaluated as a
Literal(LiteralString, LiteralInt, ...) then the equality is only true
when types and value are equal.
https://typing.readthedocs.io/en/latest/spec/literal.html#legal-and-illegal-parameterizations
The illegal parameterizations are mostly implemented I'm currently
checking the slice expression and the slice type to make sure it's
valid.
https://typing.readthedocs.io/en/latest/spec/literal.html#shortening-unions-of-literals
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
This PR enables red-knot to support type narrowing based on `and` and
`or` conditionals, including nested combinations and their negation (for
`elif` / `else` blocks and for `not` operator). Part of #13694.
In order to address this properly (hopefully 😅), I had to run
`NarrowingConstraintsBuilder` functions recursively. In the first commit
I introduced a minor refactor - instead of mutating `self.constraints`,
the new constraints are now returned as function return values. I also
modified the constraints map to be optional, preventing unnecessary
hashmap allocations.
Thanks @carljm for your support on this :)
The second commit contains the logic and tests for handling boolean ops,
with improvements to intersections handling in `is_subtype_of` .
As I'm still new to Rust and the internals of type checkers, I’d be more
than happy to hear any insights or suggestions.
Thank you!
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Encountered this while running red-knot benchmarks on the `black`
codebase.
Fixes two of the issues in #13478.
## Test Plan
Added a regression test.
## Summary
Removes `Type::None` in favor of `KnownClass::NoneType.to_instance(…)`.
closes#13670
## Performance
There is a -4% performance regression on our red-knot benchmark. This is due to the fact that we now have to import `_typeshed` as a module, and infer types.
## Test Plan
Existing tests pass.
## Summary
This PR adds a new salsa query and an ingredient to resolve all the
variables involved in an unpacking assignment like `(a, b) = (1, 2)` at
once. Previously, we'd recursively try to match the correct type for
each definition individually which will result in creating duplicate
diagnostics.
This PR still doesn't solve the duplicate diagnostics issue because that
requires a different solution like using salsa accumulator or
de-duplicating the diagnostics manually.
Related: #13773
## Test Plan
Make sure that all unpack assignment test cases pass, there are no
panics in the corpus tests.
## Todo
- [x] Look at the performance regression
## Summary
Removing more TODOs from the augmented assignment test suite. Now, if
the _target_ is a union, we correctly infer the union of results:
```python
if flag:
f = Foo()
else:
f = 42.0
f += 12
```
## Summary
One of the follow-ups from augmented assignment inference, now that
`Type::Unbound` has been removed.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
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## Summary
- Remove `Type::Unbound`
- Handle (potential) unboundness as a concept orthogonal to the type
system (see new `Symbol` type)
- Improve existing and add new diagnostics related to (potential)
unboundness
closes#13671
## Test Plan
- Update existing markdown-based tests
- Add new tests for added/modified functionality
## Summary
This PR fixes a panic which can occur in an unpack assignment when:
* (number of target expressions) - (number of tuple types) > 2
* There's a starred expression
The reason being that the `insert` panics because the index is greater
than the length.
This is an error case and so practically it should occur very rarely.
The solution is to resize the types vector to match the number of
expressions and then insert the starred expression type.
## Test Plan
Add a new test case.
## Summary
This PR creates a new `TypeCheckDiagnosticsBuilder` for the
`TypeCheckDiagnostics` struct. The main motivation behind this is to
separate the helpers required to build the diagnostics from the type
inference builder itself. This allows us to use such helpers outside of
the inference builder like for example in the unpacking logic in
https://github.com/astral-sh/ruff/pull/13979.
## Test Plan
`cargo insta test`
## Summary
These cases aren't handled correctly yet -- some of them are waiting on
refactors to `Unbound` before fixing. Part of #12699.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
I noticed that augmented assignments on floats were yielding "not
supported" diagnostics. If the dunder isn't bound at all, we should use
binary operator semantics, rather than treating it as not-callable.
## Summary
Minor follow-up to #13917 — thanks @AlexWaygood for the post-merge
review.
- Add
SliceLiteralType::as_tuple
- Use .expect() instead of SAFETY
comment
- Match on ::try_from
result
- Add TODO comment regarding raising a diagnostic for `"foo"["bar":"baz"]`
## Summary
This PR adds support for heterogenous `tuple` annotations to red-knot.
It does the following:
- Extends `infer_type_expression` so that it understands tuple
annotations
- Changes `infer_type_expression` so that `ExprStarred` nodes in type
annotations are inferred as `Todo` rather than `Unknown` (they're valid
in PEP-646 tuple annotations)
- Extends `Type::is_subtype_of` to understand when one heterogenous
tuple type can be understood to be a subtype of another (without this
change, the PR would have introduced new false-positive errors to some
existing mdtests).
## Summary
- Add a new `Type::SliceLiteral` variant
- Infer `SliceLiteral` types for slice expressions, such as
`<int-literal>:<int-literal>:<int-literal>`.
- Infer "sliced" literal types for subscript expressions using slices,
such as `<string-literal>[<slice-literal>]`.
- Infer types for expressions involving slices of tuples:
`<tuple>[<slice-literal>]`.
closes#13853
## Test Plan
- Unit tests for indexing/slicing utility functions
- Markdown-based tests for
- Subscript expressions `tuple[slice]`
- Subscript expressions `string_literal[slice]`
- Subscript expressions `bytes_literal[slice]`
## Summary
This does two things:
- distribute negated intersections when building up intersections (i.e.
going from `A & ~(B & C)` to `(A & ~B) | (A & ~C)`) (fixing #13931)
## Test Plan
`cargo test`
## Summary
This PR adds type narrowing in `and` and `or` expressions, for example:
```py
class A: ...
x: A | None = A() if bool_instance() else None
isinstance(x, A) or reveal_type(x) # revealed: None
```
## Test Plan
New mdtests 😍
## Summary
After #13918 has landed, narrowing constraint negation became easy, so
adding support for `not` operator.
## Test Plan
Added a new mdtest file for `not` expression.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
As python uses short-circuiting boolean operations in runtime, we should
mimic that logic in redknot as well.
For example, we should detect that in the following code `x` might be
undefined inside the block:
```py
if flag or (x := 1):
print(x)
```
## Test Plan
Added mdtest suit for boolean expressions.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Add support for type narrowing in elif and else scopes as part of
#13694.
## Test Plan
- mdtest
- builder unit test for union negation.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Add type narrowing for `isinstance(object, classinfo)` [1] checks:
```py
x = 1 if flag else "a"
if isinstance(x, int):
reveal_type(x) # revealed: Literal[1]
```
closes#13893
[1] https://docs.python.org/3/library/functions.html#isinstance
## Test Plan
New Markdown-based tests in `narrow/isinstance.md`.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
A minor quality-of-life improvement: add
[`#[track_caller]`](https://doc.rust-lang.org/reference/attributes/codegen.html#the-track_caller-attribute)
attribute to `Type::expect_xyz()` methods and some `TypeInference` methods such that the panic-location
is reported one level higher up in the stack trace.
before: reports location inside the `Type::expect_class_literal()`
method. Not very useful.
```
thread 'types::infer::tests::deferred_annotation_builtin' panicked at crates/red_knot_python_semantic/src/types.rs:304:14:
Expected a Type::ClassLiteral variant
```
after: reports location at the `Type::expect_class_literal()` call site,
where the error was made.
```
thread 'types::infer::tests::deferred_annotation_builtin' panicked at crates/red_knot_python_semantic/src/types/infer.rs:4302:14:
Expected a Type::ClassLiteral variant
```
## Test Plan
Called `expect_class_literal()` on something that's not a
`Type::ClassLiteral` and saw that the error was reported at the call
site.
## Summary
* Rename `Type::Class` => `Type::ClassLiteral`
* Rename `Type::Function` => `Type::FunctionLiteral`
* Do not rename `Type::Module`
* Remove `*Literal` suffixes in `display::LiteralTypeKind` variants, as
per clippy suggestion
* Get rid of `Type::is_class()` in favor of `is_subtype_of(…, 'type')`;
modifiy `is_subtype_of` to support this.
* Add new `Type::is_xyz()` methods and use them instead of matching on
`Type` variants.
closes#13863
## Test Plan
New `is_subtype_of_class_literals` unit test.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
- Properly treat the empty intersection as being of type `object`.
- Consequently, change the simplification method to explicitly add
`Never` to the positive side of the intersection when collapsing a type
such as `int & str` to `Never`, as opposed to just clearing both the
positive and the negative side.
- Minor code improvement in `bindings_ty`: use `peekable()` to check
whether the iterator over constraints is empty, instead of handling
first and subsequent elements separately.
fixes#13870
## Test Plan
- New unit tests for `IntersectionBuilder` to make sure the empty
intersection represents `object`.
- Markdown-based regression test for the original issue in #13870
Add the following subtype relations:
- `BooleanLiteral <: object`
- `IntLiteral <: object`
- `StringLiteral <: object`
- `LiteralString <: object`
- `BytesLiteral <: object`
Added a test case for `bool <: int`.
## Test Plan
New unit tests.
Add type narrowing for `!=` expression as stated in
#13694.
### Test Plan
Add tests in new md format.
---------
Co-authored-by: David Peter <mail@david-peter.de>
## Summary
A small fix for comparisons of multiple comparators.
Instead of comparing each comparator to the leftmost item, we should
compare it to the closest item on the left.
While implementing this, I noticed that we don’t yet narrow Yoda
comparisons (e.g., `True is x`), so I didn’t change that behavior in
this PR.
## Test Plan
Added some mdtests 🎉
## Summary
Just a drive-by change that occurred to me while I was looking at
`Type::is_subtype_of`: the existing pattern for unions on the *right
hand side*:
```rs
(ty, Type::Union(union)) => union
.elements(db)
.iter()
.any(|&elem_ty| ty.is_subtype_of(db, elem_ty)),
```
is not (generally) correct if the *left hand side* is a union.
## Test Plan
Added new test cases for `is_subtype_of` and `!is_subtype_of`
## Summary
- Consistent naming: `BoolLiteral` => `BooleanLiteral` (it's mainly the
`Ty::BoolLiteral` variant that was renamed)
I tripped over this a few times now, so I thought I'll smooth it out.
- Add a new test case for `Literal[True] <: bool`, as suggested here:
https://github.com/astral-sh/ruff/pull/13781#discussion_r1804922827
Remove unnecessary uses of `.as_ref()`, `.iter()`, `&**` and similar, mostly in situations when iterating over variables. Many of these changes are only possible following #13826, when we bumped our MSRV to 1.80: several useful implementations on `&Box<[T]>` were only stabilised in Rust 1.80. Some of these changes we could have done earlier, however.
Implemented some points from
https://github.com/astral-sh/ruff/issues/12701
- Handle Unknown and Any in Unary operation
- Handle Boolean in binary operations
- Handle instances in unary operation
- Consider division by False to be division by zero
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
- Refactored comparison type inference functions in `infer.rs`: Changed
the return type from `Option` to `Result` to lay the groundwork for
providing more detailed diagnostics.
- Updated diagnostic messages.
This is a small step toward improving diagnostics in the future.
Please refer to #13787
## Test Plan
mdtest included!
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
This fixes an edge case that @carljm and I missed when implementing
https://github.com/astral-sh/ruff/pull/13800. Namely, if the left-hand
operand is the _exact same type_ as the right-hand operand, the
reflected dunder on the right-hand operand is never tried:
```pycon
>>> class Foo:
... def __radd__(self, other):
... return 42
...
>>> Foo() + Foo()
Traceback (most recent call last):
File "<python-input-1>", line 1, in <module>
Foo() + Foo()
~~~~~~^~~~~~~
TypeError: unsupported operand type(s) for +: 'Foo' and 'Foo'
```
This edge case _is_ covered in Brett's blog at
https://snarky.ca/unravelling-binary-arithmetic-operations-in-python/,
but I missed it amongst all the other subtleties of this algorithm. The
motivations and history behind it were discussed in
https://mail.python.org/archives/list/python-dev@python.org/thread/7NZUCODEAPQFMRFXYRMGJXDSIS3WJYIV/
## Test Plan
I added an mdtest for this cornercase.
## Summary
- Add `Type::is_disjoint_from` as a way to test whether two types
overlap
- Add a first set of simplification rules for intersection types
- `S & T = S` for `S <: T`
- `S & ~T = Never` for `S <: T`
- `~S & ~T = ~T` for `S <: T`
- `A & ~B = A` for `A` disjoint from `B`
- `A & B = Never` for `A` disjoint from `B`
- `bool & ~Literal[bool] = Literal[!bool]`
resolves one item in #12694
## Open questions:
- Can we somehow leverage the (anti) symmetry between `positive` and
`negative` contributions? I could imagine that there would be a way if
we had `Type::Not(type)`/`Type::Negative(type)`, but with the
`positive`/`negative` architecture, I'm not sure. Note that there is a
certain duplication in the `add_positive`/`add_negative` functions (e.g.
`S & ~T = Never` is implemented twice), but other rules are actually not
perfectly symmetric: `S & T = S` vs `~S & ~T = ~T`.
- I'm not particularly proud of the way `add_positive`/`add_negative`
turned out. They are long imperative-style functions with some
mutability mixed in (`to_remove`). I'm happy to look into ways to
improve this code *if we decide to go with this approach* of
implementing a set of ad-hoc rules for simplification.
- ~~Is it useful to perform simplifications eagerly in
`add_positive`/`add_negative`? (@carljm)~~ This is what I did for now.
## Test Plan
- Unit tests for `Type::is_disjoint_from`
- Observe changes in Markdown-based tests
- Unit tests for `IntersectionBuilder::build()`
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Minor cleanup and consistent formatting of the Markdown-based tests.
- Removed lots of unnecessary `a`, `b`, `c`, … variables.
- Moved test assertions (`# revealed:` comments) closer to the tested
object.
- Always separate `# revealed` and `# error` comments from the code by
two spaces, according to the discussion
[here](https://github.com/astral-sh/ruff/pull/13746/files#r1799385758).
This trades readability for consistency in some cases.
- Fixed some headings
Summary
---------
PEP 695 Generics introduce a scope inside a class statement's arguments
and keywords.
```
class C[T](A[T]): # the T in A[T] is not from the global scope but from a type-param-specfic scope
...
```
When doing inference on the class bases, we currently have been doing
base class expression lookups in the global scope. Not an issue without
generics (since a scope is only created when generics are present).
This change instead makes sure to stop the global scope inference from
going into expressions within this sub-scope. Since there is a separate
scope, `check_file` and friends will trigger inference on these
expressions still.
Another change as a part of this is making sure that `ClassType` looks
up its bases in the right scope.
Test Plan
----------
`cargo test --package red_knot_python_semantic generics` will run the
markdown test that previously would panic due to scope lookup issues
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Carl Meyer <carl@astral.sh>
This reverts https://github.com/astral-sh/ruff/pull/13799, and restores
the previous behavior, which I think was the most pragmatic and useful
version of the divide-by-zero error, if we will emit it at all.
In general, a type checker _does_ emit diagnostics when it can detect
something that will definitely be a problem for some inhabitants of a
type, but not others. For example, `x.foo` if `x` is typed as `object`
is a type error, even though some inhabitants of the type `object` will
have a `foo` attribute! The correct fix is to make your type annotations
more precise, so that `x` is assigned a type which definitely has the
`foo` attribute.
If we will emit it divide-by-zero errors, it should follow the same
logic. Dividing an inhabitant of the type `int` by zero may not emit an
error, if the inhabitant is an instance of a subclass of `builtins.int`
that overrides division. But it may emit an error (more likely it will).
If you don't want the diagnostic, you can clarify your type annotations
to require an instance of your safe subclass.
Because the Python type system doesn't have the ability to explicitly
reflect the fact that divide-by-zero is an error in type annotations
(e.g. for `int.__truediv__`), or conversely to declare a type as safe
from divide-by-zero, or include a "nonzero integer" type which it is
always safe to divide by, the analogy doesn't fully apply. You can't
explicitly mark your subclass of `int` as safe from divide-by-zero, we
just semi-arbitrarily choose to silence the diagnostic for subclasses,
to avoid false positives.
Also, if we fully followed the above logic, we'd have to error on every
`int / int` because the RHS `int` might be zero! But this would likely
cause too many false positives, because of the lack of a "nonzero
integer" type.
So this is just a pragmatic choice to emit the diagnostic when it is
very likely to be an error. It's unclear how useful this diagnostic is
in practice, but this version of it is at least very unlikely to cause
harm.
If the LHS is just `int` or `float` type, that type includes custom
subclasses which can arbitrarily override division behavior, so we
shouldn't emit a divide-by-zero error in those cases.
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Add type inference for comparisons involving union types. For example:
```py
one_or_two = 1 if flag else 2
reveal_type(one_or_two <= 2) # revealed: Literal[True]
reveal_type(one_or_two <= 1) # revealed: bool
reveal_type(one_or_two <= 0) # revealed: Literal[False]
```
closes#13779
## Test Plan
See `resources/mdtest/comparison/unions.md`
## Summary
Fixes the bug described in #13514 where an unbound public type defaulted
to the type or `Unknown`, whereas it should only be the type if unbound.
## Test Plan
Added a new test case
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
This PR adds a debug assertion that asserts that `TypeInference::extend`
is only called on results that have the same scope.
This is critical because `expressions` uses `ScopedExpressionId` that
are local and merging expressions from different
scopes would lead to incorrect expression types.
We could consider storing `scope` only on `TypeInference` for debug
builds. Doing so has the advantage that the `TypeInference` type is
smaller of which we'll have many. However, a `ScopeId` is a `u32`... so
it shouldn't matter that much and it avoids storing the `scope` both on
`TypeInference` and `TypeInferenceBuilder`
## Test Plan
`cargo test`
## Summary
This PR implements comparisons for (tuple, tuple).
It will close#13688 and complete an item in #13618 once merged.
## Test Plan
Basic tests are included for (tuple, tuple) comparisons.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Just a small simplification to remove some unnecessary complexity here.
Rather than using separate branches for subscript expressions involving
boolean literals, we can simply convert them to integer literals and
reuse the logic in the `IntLiteral` branches.
## Test Plan
`cargo test -p red_knot_python_semantic`
## Summary
This PR adds support for unpacking tuple expression in an assignment
statement where the target expression can be a tuple or a list (the
allowed sequence targets).
The implementation introduces a new `infer_assignment_target` which can
then be used for other targets like the ones in for loops as well. This
delegates it to the `infer_definition`. The final implementation uses a
recursive function that visits the target expression in source order and
compares the variable node that corresponds to the definition. At the
same time, it keeps track of where it is on the assignment value type.
The logic also accounts for the number of elements on both sides such
that it matches even if there's a gap in between. For example, if
there's a starred expression like `(a, *b, c) = (1, 2, 3)`, then the
type of `a` will be `Literal[1]` and the type of `b` will be
`Literal[2]`.
There are a couple of follow-ups that can be done:
* Use this logic for other target positions like `for` loop
* Add diagnostics for mis-match length between LHS and RHS
## Test Plan
Add various test cases using the new markdown test framework.
Validate that existing test cases pass.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Porting infer tests to new markdown tests framework.
Link to the corresponding issue: #13696
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
- Fix a bug with `… is not …` type guards.
Previously, in an example like
```py
x = [1]
y = [1]
if x is not y:
reveal_type(x)
```
we would infer a type of `list[int] & ~list[int] == Never` for `x`
inside the conditional (instead of `list[int]`), since we built a
(negative) intersection with the type of the right hand side (`y`).
However, as this example shows, this assumption can only be made for
singleton types (types with a single inhabitant) such as `None`.
- Add support for `… is …` type guards.
closes#13715
## Test Plan
Moved existing `narrow_…` tests to Markdown-based tests and added new
ones (including a regression test for the bug described above). Note
that will create some conflicts with
https://github.com/astral-sh/ruff/pull/13719. I tried to establish the
correct organizational structure as proposed in
https://github.com/astral-sh/ruff/pull/13719#discussion_r1800188105
This adds documentation for the new test framework.
I also added documentation for the planned design of features we haven't
built yet (clearly marked as such), so that this doc can become the sole
source of truth for the test framework design (we don't need to refer
back to the original internal design document.)
Also fixes a few issues in the test framework implementation that were
discovered in writing up the docs.
---------
Co-authored-by: T-256 <132141463+T-256@users.noreply.github.com>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
## Summary
Adds a markdown-based test framework for writing tests of type inference
and type checking. Fixes#11664.
Implements the basic required features. A markdown test file is a suite
of tests, each test can contain one or more Python files, with
optionally specified path/name. The test writes all files to an
in-memory file system, runs red-knot, and matches the resulting
diagnostics against `Type: ` and `Error: ` assertions embedded in the
Python source as comments.
We will want to add features like incremental tests, setting custom
configuration for tests, writing non-Python files, testing syntax
errors, capturing full diagnostic output, etc. There's also plenty of
room for improved UX (colored output?).
## Test Plan
Lots of tests!
Sample of the current output when a test fails:
```
Running tests/inference.rs (target/debug/deps/inference-7c96590aa84de2a4)
running 1 test
test inference::path_1_resources_inference_numbers_md ... FAILED
failures:
---- inference::path_1_resources_inference_numbers_md stdout ----
inference/numbers.md - Numbers - Floats
/src/test.py
line 2: unexpected error: [invalid-assignment] "Object of type `Literal["str"]` is not assignable to `int`"
thread 'inference::path_1_resources_inference_numbers_md' panicked at crates/red_knot_test/src/lib.rs:60:5:
Some tests failed.
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
failures:
inference::path_1_resources_inference_numbers_md
test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.19s
error: test failed, to rerun pass `-p red_knot_test --test inference`
```
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Fixed a TODO by adding another TODO. It's the red-knot way!
## Summary
`builtins.type` can be subscripted at runtime on Python 3.9+, even
though it has no `__class_getitem__` method and its metaclass (which
is... itself) has no `__getitem__` method. The special case is
[hardcoded directly into `PyObject_GetItem` in
CPython](744caa8ef4/Objects/abstract.c (L181-L184)).
We just have to replicate the special case in our semantic model.
This will fail at runtime on Python <3.9. However, there's a bunch of
outstanding questions (detailed in the TODO comment I added) regarding
how we deal with subscriptions of other generic types on lower Python
versions. Since we want to avoid too many false positives for now, I
haven't tried to address this; I've just made `type` subscriptable on
all Python versions.
## Test Plan
`cargo test -p red_knot_python_semantic --lib`
## Summary
Implements string literal comparisons and fallbacks to `str` instance
for `LiteralString`.
Completes an item in #13618
## Test Plan
- Adds a dedicated test with non exhaustive cases
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Implements the comparison operator for `[Type::IntLiteral]` and
`[Type::BooleanLiteral]` (as an artifact of special handling of `True` and
`False` in python).
Sets the framework to implement more comparison for types known at
static time (e.g. `BooleanLiteral`, `StringLiteral`), allowing us to only
implement cases of the triplet `<left> Type`, `<right> Type`, `CmpOp`.
Contributes to #12701 (without checking off an item yet).
## Test Plan
- Added a test for the comparison of literals that should include most
cases of note.
- Added a test for the comparison of int instances
Please note that the cases do not cover 100% of the branches as there
are many and the current testing strategy with variables make this
fairly confusing once we have too many in one test.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
...and remove periods from messages that don't span more than a single
sentence.
This is more consistent with how we present user-facing messages in uv
(which has a defined style guide).
## Summary
You can now call `return_ty_result` to operate on a `Result` directly
thereby using your own diagnostics, as in:
```rust
return dunder_getitem_method
.call(self.db, &[slice_ty])
.return_ty_result(self.db, value.as_ref().into(), self)
.unwrap_or_else(|err| {
self.add_diagnostic(
(&**value).into(),
"call-non-callable",
format_args!(
"Method `__getitem__` is not callable on object of type '{}'.",
value_ty.display(self.db),
),
);
err.return_ty()
});
```
Adds a diagnostic for division by the integer zero in `//`, `/`, and
`%`.
Doesn't handle `<int> / 0.0` because we don't track the values of float
literals.
This variant shows inference that is not yet implemented..
## Summary
PR #13500 reopened the idea of adding a new type variant to keep track
of not-implemented features in Red Knot.
It was based off of #12986 with a more generic approach of keeping track
of different kind of unknowns. Discussion in #13500 agreed that keeping
track of different `Unknown` is complicated for now, and this feature is
better achieved through a new variant of `Type`.
### Requirements
Requirements for this implementation can be summed up with some extracts
of comment from @carljm on the previous PR
> So at the moment we are leaning towards simplifying this PR to just
use a new top-level variant, which behaves like Any and Unknown but
represents inference that is not yet implemented in red-knot.
> I think the general rule should be that Todo should propagate only
when the presence of the input Todo caused the output to be unknown.
>
> To take a specific example, the inferred result of addition must be
Unknown if either operand is Unknown. That is, Unknown + X will always
be Unknown regardless of what X is. (Same for X + Unknown.) In this
case, I believe that Unknown + Todo (or Todo + Unknown) should result in
Unknown, not result in Todo. If we fix the upstream source of the Todo,
the result would still be Unknown, so it's not useful to propagate the
Todo in this case: it wrongly suggests that the output is unknown
because of a todo item.
## Test Plan
This PR does not introduce new tests, but it did required to edit some
tests with the display of `[Type::Todo]` (currently `@Todo`), which
suggests that those test are placeholders requirements for features we
don't support yet.
While working on https://github.com/astral-sh/ruff/pull/13576 I noticed
that it was really hard to tell which assertion failed in some of these
test cases. This could be expanded to elsewhere, but I've heard this
test suite format won't be around for long?
David Peter
InSync
Douglas Creager
Connor Skees
Micha Reiser
Samodya Abeysiriwardane
Shaygan Hooshyari
cake-monotone
Dhruv Manilawala
Carl Meyer
Shantanu
Alex Waygood
Charlie Marsh
TomerBin
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