## Summary
This changeset adds support for precise type-inference and
boundness-handling of definitions inside control-flow branches with
statically-known conditions, i.e. test-expressions whose truthiness we
can unambiguously infer as *always false* or *always true*.
This branch also includes:
- `sys.platform` support
- statically-known branches handling for Boolean expressions and while
loops
- new `target-version` requirements in some Markdown tests which were
now required due to the understanding of `sys.version_info` branches.
closes#12700closes#15034
## Performance
### `tomllib`, -7%, needs to resolve one additional module (sys)
| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
|:---|---:|---:|---:|---:|
| `./red_knot_main --project /home/shark/tomllib` | 22.2 ± 1.3 | 19.1 |
25.6 | 1.00 |
| `./red_knot_feature --project /home/shark/tomllib` | 23.8 ± 1.6 | 20.8
| 28.6 | 1.07 ± 0.09 |
### `black`, -6%
| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
|:---|---:|---:|---:|---:|
| `./red_knot_main --project /home/shark/black` | 129.3 ± 5.1 | 119.0 |
137.8 | 1.00 |
| `./red_knot_feature --project /home/shark/black` | 136.5 ± 6.8 | 123.8
| 147.5 | 1.06 ± 0.07 |
## Test Plan
- New Markdown tests for the main feature in
`statically-known-branches.md`
- New Markdown tests for `sys.platform`
- Adapted tests for `EllipsisType`, `Never`, etc
When importing a nested module, we were correctly creating a binding for
the top-most parent, but we were binding that to the nested module, not
to that parent module. Moreover, we weren't treating those submodules as
members of their containing parents. This PR addresses both issues, so
that nested imports work as expected.
As discussed in ~Slack~ whatever chat app I find myself in these days
😄, this requires keeping track of which modules have been imported
within the current file, so that when we resolve member access on a
module reference, we can see if that member has been imported as a
submodule. If so, we return the submodule reference immediately, instead
of checking whether the parent module's definition defines the symbol.
This is currently done in a flow insensitive manner. The `SemanticIndex`
now tracks all of the modules that are imported (via `import`, not via
`from...import`). The member access logic mentioned above currently only
considers module imports in the file containing the attribute
expression.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Inferred and declared types for function parameters, in the function
body scope.
Fixes#13693.
## Test Plan
Added mdtests.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## 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
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
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
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
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
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
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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 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
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>
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.
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>
## 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>
I noticed that this pattern sometimes occurs in typeshed:
```
if ...:
from foo import bar
else:
def bar(): ...
```
If we have the rule that symbols with declarations only use declarations
for the public type, then this ends up resolving as `Unknown |
Literal[bar]`, because we didn't consider the import to be a
declaration.
I think the most straightforward thing here is to also consider imports
as declarations. The same rationale applies as for function and class
definitions: if you shadow an import, you should have to explicitly
shadow with an annotation, rather than just doing it
implicitly/accidentally.
We may also ultimately need to re-evaluate the rule that public type
considers only declarations, if there are declarations.
Use declared types in inference and checking. This means several things:
* Imports prefer declarations over inference, when declarations are
available.
* When we encounter a binding, we check that the bound value's inferred
type is assignable to the live declarations of the bound symbol, if any.
* When we encounter a declaration, we check that the declared type is
assignable from the inferred type of the symbol from previous bindings,
if any.
* When we encounter a binding+declaration, we check that the inferred
type of the bound value is assignable to the declared type.
Add support for declared types to the semantic index. This involves a
lot of renaming to clarify the distinction between bindings and
declarations. The Definition (or more specifically, the DefinitionKind)
becomes responsible for determining which definitions are bindings,
which are declarations, and which are both, and the symbol table
building is refactored a bit so that the `IS_BOUND` (renamed from
`IS_DEFINED` for consistent terminology) flag is always set when a
binding is added, rather than being set separately (and requiring us to
ensure it is set properly).
The `SymbolState` is split into two parts, `SymbolBindings` and
`SymbolDeclarations`, because we need to store live bindings for every
declaration and live declarations for every binding; the split lets us
do this without storing more than we need.
The massive doc comment in `use_def.rs` is updated to reflect bindings
vs declarations.
The `UseDefMap` gains some new APIs which are allow-unused for now,
since this PR doesn't yet update type inference to take declarations
into account.
Add `::is_empty` and `::union` methods to the `BitSet` implementation.
Allowing unused for now, until these methods become used later with the
declared-types implementation.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
This PR adds support for control flow for match statement.
It also adds the necessary infrastructure required for narrowing
constraints in case blocks and implements the logic for
`PatternMatchSingleton` which is either `None` / `True` / `False`. Even
after this the inferred type doesn't get simplified completely, there's
a TODO for that in the test code.
## Test Plan
Add test cases for control flow for (a) when there's a wildcard pattern
and (b) when there isn't. There's also a test case to verify the
narrowing logic.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
My plan for handling declared types is to introduce a `Declaration` in
addition to `Definition`. A `Declaration` is an annotation of a name
with a type; a `Definition` is an actual runtime assignment of a value
to a name. A few things (an annotated function parameter, an
annotated-assignment with an RHS) are both a `Definition` and a
`Declaration`.
This more cleanly separates type inference (only cares about
`Definition`) from declared types (only impacted by a `Declaration`),
and I think it will work out better than trying to squeeze everything
into `Definition`. One of the tests in this PR
(`annotation_only_assignment_transparent_to_local_inference`)
demonstrates one reason why. The statement `x: int` should have no
effect on local inference of the type of `x`; whatever the locally
inferred type of `x` was before `x: int` should still be the inferred
type after `x: int`. This is actually quite hard to do if `x: int` is
considered a `Definition`, because a core assumption of the use-def map
is that a `Definition` replaces the previous value. To achieve this
would require some hackery to effectively treat `x: int` sort of as if
it were `x: int = x`, but it's not really even equivalent to that, so
this approach gets quite ugly.
As a first step in this plan, this PR stops treating AnnAssign with no
RHS as a `Definition`, which fixes behavior in a couple added tests.
This actually makes things temporarily worse for the ellipsis-type test,
since it is defined in typeshed only using annotated assignments with no
RHS. This will be fixed properly by the upcoming addition of
declarations, which should also treat a declared type as sufficient to
import a name, at least from a stub.
