## Summary
Part of #13085, this PR updates the comprehension definition to handle
multiple targets.
## Test Plan
Update existing semantic index test case for comprehension with multiple
targets. Running corpus tests shouldn't panic.
Add support for non-local name lookups.
There's one TODO around annotated assignments without a RHS; these need
a fair amount of attention, which they'll get in an upcoming PR about
declared vs inferred types.
Fixes#11663
Test coverage for #13131 wasn't as good as I thought it was, because
although we infer a lot of types in stubs in typeshed, we don't check
typeshed, and therefore we don't do scope-level inference and pull all
types for a scope. So we didn't really have good test coverage for
scope-level inference in a stub. And because of this, I got the code for
supporting that wrong, meaning that if we did scope-level inference with
deferred types, we'd end up never populating the deferred types in the
scope's `TypeInference`, which causes panics like #13160.
Here I both add test coverage by running the corpus tests both as `.py`
and as `.pyi` (which reveals the panic), and I fix the code to support
deferred types in scope inference.
This also revealed a problem with deferred types in generic functions,
which effectively span two scopes. That problem will require a bit more
thought, and I don't want to block this PR on it, so for now I just
don't defer annotations on generic functions.
Fixes#13160.
## Summary
Follow-up to #13147, this PR implements the `AstNode` for `Identifier`.
This makes it easier to create the `NodeKey` in red knot because it uses
a generic method to construct the key from `AnyNodeRef` and is important
for definitions that are created only on identifiers instead of
`ExprName`.
## Test Plan
`cargo test` and `cargo clippy`
## Summary
This PR adds definition for match patterns.
## Test Plan
Update the existing test case for match statement symbols to verify that
the definitions are added as well.
The `UnionBuilder` builds `builtins.bool` when handed `Literal[True]`
and `Literal[False]`.
Caveat: If the builtins module is unfindable somehow, the builder falls
back to the union type of these two literals.
First task from #12694
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Adds basic support for inferring the type resulting from a call
expression. This only works for the *result* of call expressions; it
performs no inference on parameters. It also intentionally does nothing
with class instantiation, `__call__` implementors, or lambdas.
## Test Plan
Adds a test that it infers the right thing!
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
- Introduce methods for inferring annotation and type expressions.
- Correctly infer explicit return types from functions where they are
simple names that can be resolved in scope.
Contributes to #12701 by way of helping unlock call expressions (this
does not remotely finish that, as it stands, but it gets us moving that
direction).
## Test Plan
Added a test for function return types which use the name form of an
annotation expression, since this is aiming toward call expressions.
When we extend this to working for other annotation and type expression
positions, we should add explicit tests for those as well.
---------
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
Prototype deferred evaluation of type expressions by deferring
evaluation of class bases in a stub file. This allows self-referential
class definitions, as occur with the definition of `str` in typeshed
(which inherits `Sequence[str]`).
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Just what it says on the tin: adds basic `EllipsisType` inference for
any time `...` appears in the AST.
## Test Plan
Test that `x = ...` produces exactly what we would expect.
---------
Co-authored-by: Carl Meyer <carl@oddbird.net>
## Summary
The resulting type when multiplying a string literal by an integer
literal is one of two types:
- `StringLiteral`, in the case where it is a reasonably small resulting
string (arbitrarily bounded here to 4096 bytes, roughly a page on many
operating systems), including the fully expanded string.
- `LiteralString`, matching Pyright etc., for strings larger than that.
Additionally:
- Switch to using `Box<str>` instead of `String` for the internal value
of `StringLiteral`, saving some non-trivial byte overhead (and keeping
the total number of allocations the same).
- Be clearer and more accurate about which types we ought to defer to in
`StringLiteral` and `LiteralString` member lookup.
## Test Plan
Added a test case covering multiplication times integers: positive,
negative, zero, and in and out of bounds.
---------
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
This fixes the outstanding TODO and make it easier to work with new
cases. (Tidy first, *then* implement, basically!)
## Test Plan
After making this change all the existing tests still pass. A classic
refactor win. 🎉
# Summary
Add support for the first unary operator: negating integer literals. The
resulting type is another integer literal, with the value being the
negated value of the literal. All other types continue to return
`Type::Unknown` for the present, but this is designed to make it easy to
extend easily with other combinations of operator and operand.
Contributes to #12701.
## Test Plan
Add tests with basic negation, including of very large integers and
double negation.
## Summary
Introduce a `StringLiteralType` with corresponding `Display` type and a
relatively basic test that the resulting representation is as expected.
Note: we currently always allocate for `StringLiteral` types. This may
end up being a perf issue later, at which point we may want to look at
other ways of representing `value` here, i.e. with some kind of smarter
string structure which can reuse types. That is most likely to show up
with e.g. concatenation.
Contributes to #12701.
## Test Plan
Added a test for individual strings with both single and double quotes
as well as concatenated strings with both forms.
This PR has the `SemanticIndexBuilder` visit function definition
annotations before adding the function symbol/name to the builder.
For example, the following snippet no longer causes a panic:
```python
def bool(x) -> bool:
Return True
```
Note: This fix changes the ordering of the global symbol table.
Closes#13069
## Summary
This PR adds symbols introduced by `for` loops to red-knot:
- `x` in `for x in range(10): pass`
- `x` and `y` in `for x, y in d.items(): pass`
- `a`, `b`, `c` and `d` in `for [((a,), b), (c, d)] in foo: pass`
## Test Plan
Several tests added, and the assertion in the benchmarks has been
updated.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
This PR adds the `bytes` type to red-knot:
- Added the `bytes` type
- Added support for bytes literals
- Support for the `+` operator
Improves on #12701
Big TODO on supporting and normalizing r-prefixed bytestrings
(`rb"hello\n"`)
## Test Plan
Added a test for a bytes literals, concatenation, and corner values
The `SemanticIndexBuilder` was causing a cycle in a salsa query by
attempting to resolve the target before the value in a named expression
(e.g. `x := x+1`). This PR swaps the order, avoiding a panic.
Closes#13012.
## Summary
This PR adds symbols and definitions introduced by `with` statements.
The symbols and definitions are introduced for each with item. The type
inference is updated to call the definition region type inference
instead.
## Test Plan
Add test case to check for symbol table and definitions.
## Summary
This PR adds symbols introduced by `match` statements.
There are three patterns that introduces new symbols:
* `as` pattern
* Sequence pattern
* Mapping pattern
The recursive nature of the visitor makes sure that all symbols are
added.
## Test Plan
Add test case for all types of patterns that introduces a symbol.
## Summary
This PR adds definition for augmented assignment. This is similar to
annotated assignment in terms of implementation.
An augmented assignment should also record a use of the variable but
that's a TODO for now.
## Test Plan
Add test case to validate that a definition is added.
Extend the `UseDefMap` to also track which constraints (provided by e.g.
`if` tests) apply to each visible definition.
Uses a custom `BitSet` and `BitSetArray` to track which constraints
apply to which definitions, while keeping data inline as much as
possible.
## Summary
This PR adds support for adding symbols and definitions for function and
lambda parameters to the semantic index.
### Notes
* The default expression of a parameter is evaluated in the enclosing
scope (not the type parameter or function scope).
* The annotation expression of a parameter is evaluated in the type
parameter scope if they're present other in the enclosing scope.
* The symbols and definitions are added in the function parameter scope.
### Type Inference
There are two definitions `Parameter` and `ParameterWithDefault` and
their respective `*_definition` methods on the type inference builder.
These methods are preferred and are re-used when checking from a
different region.
## Test Plan
Add test case for validating that the parameters are defined in the
function / lambda scope.
### Benchmark update
Validated the difference in diagnostics for benchmark code between
`main` and this branch. All of them are either directly or indirectly
referencing one of the function parameters. The diff is in the PR description.
If a builtin is conditionally shadowed by a global, we didn't correctly
fall back to builtins for the not-defined-in-globals path (see added
test for an example.)
## Summary
This PR adds scope and definition for comprehension nodes. This includes
the following nodes:
* List comprehension
* Dictionary comprehension
* Set comprehension
* Generator expression
### Scope
Each expression here adds it's own scope with one caveat - the `iter`
expression of the first generator is part of the parent scope. For
example, in the following code snippet the `iter1` variable is evaluated
in the outer scope.
```py
[x for x in iter1]
```
> The iterable expression in the leftmost for clause is evaluated
directly in the enclosing scope and then passed as an argument to the
implicitly nested scope.
>
> Reference:
https://docs.python.org/3/reference/expressions.html#displays-for-lists-sets-and-dictionaries
There's another special case for assignment expressions:
> There is one special case: an assignment expression occurring in a
list, set or dict comprehension or in a generator expression (below
collectively referred to as “comprehensions”) binds the target in the
containing scope, honoring a nonlocal or global declaration for the
target in that scope, if one exists.
>
> Reference: https://peps.python.org/pep-0572/#scope-of-the-target
For example, in the following code snippet, the variables `a` and `b`
are available after the comprehension while `x` isn't:
```py
[a := 1 for x in range(2) if (b := 2)]
```
### Definition
Each comprehension node adds a single definition, the "target" variable
(`[_ for target in iter]`). This has been accounted for and a new
variant has been added to `DefinitionKind`.
### Type Inference
Currently, type inference is limited to a single scope. It doesn't
_enter_ in another scope to infer the types of the remaining expressions
of a node. To accommodate this, the type inference for a **scope**
requires new methods which _doesn't_ infer the type of the `iter`
expression of the leftmost outer generator (that's defined in the
enclosing scope).
The type inference for the scope region is split into two parts:
* `infer_generator_expression` (similarly for comprehensions) infers the
type of the `iter` expression of the leftmost outer generator
* `infer_generator_expression_scope` (similarly for comprehension)
infers the type of the remaining expressions except for the one
mentioned in the previous point
The type inference for the **definition** also needs to account for this
special case of leftmost generator. This is done by defining a `first`
boolean parameter which indicates whether this comprehension definition
occurs first in the enclosing expression.
## Test Plan
New test cases were added to validate multiple scenarios. Refer to the
documentation for each test case which explains what is being tested.
Make `cargo doc -p red_knot_python_semantic --document-private-items`
run warning-free. I'd still like to do this for all of ruff and start
enforcing it in CI (https://github.com/astral-sh/ruff/issues/12372) but
haven't gotten to it yet. But in the meantime I'm trying to maintain it
for at least `red_knot_python_semantic`, as it helps to ensure our doc
comments stay up to date.
A few of the comments I just removed or shortened, as their continued
relevance wasn't clear to me; please object in review if you think some
of them are important to keep!
Also remove a no-longer-needed `allow` attribute.
For type narrowing, we'll need intersections (since applying type
narrowing is just a type intersection.)
Add `IntersectionBuilder`, along with some tests for it and
`UnionBuilder` (renamed from `UnionTypeBuilder`).
We use smart builders to ensure that we always keep these types in
disjunctive normal form (DNF). That means that we never have deeply
nested trees of unions and intersections: unions flatten into unions,
intersections flatten into intersections, and intersections distribute
over unions, so the most complex tree we can ever have is a union of
intersections. We also never have a single-element union or a
single-positive-element intersection; these both just simplify to the
contained type.
Maintaining these invariants means that `UnionBuilder` doesn't
necessarily end up building a `Type::Union` (e.g. if you only add a
single type to the union, it'll just return that type instead), and
`IntersectionBuilder` doesn't necessarily build a `Type::Intersection`
(if you add a union to the intersection, we distribute the intersection
over that union, and `IntersectionBuilder` will end up returning a
`Type::Union` of intersections).
We also simplify intersections by ensuring that if a type and its
negation are both in an intersection, they simplify out. (In future this
should also respect subtyping, not just type identity, but we don't have
subtyping yet.) We do implement subtyping of `Never` as a special case
for now.
Most of this PR is unused for now until type narrowing lands; I'm just
breaking it out to reduce the review fatigue of a single massive PR.
## Summary
I'm not sure if this is useful but this is a hacky implementation to add
the filename and row / column numbers to the current Red Knot
diagnostics.
I hit this `todo!` trying to run type inference over some real modules.
Since it's a one-liner to implement it, I just did that rather than
changing to `Type::Unknown`.
Now that we have builtins available, resolve some simple cases to the
right builtin type.
We should also adjust the display for types to include their module
name; that's not done yet here.
Extend red-knot type inference to cover all syntax, so that inferring
types for a scope gives all expressions a type. This means we can run
the red-knot semantic lint on all Python code without panics. It also
means we can infer types for `builtins.pyi` without panics.
To keep things simple, this PR intentionally doesn't add any new type
inference capabilities: the expanded coverage is all achieved with
`Type::Unknown`. But this puts the skeleton in place for adding better
inference of all these language features.
I also had to add basic Salsa cycle recovery (with just `Type::Unknown`
for now), because some `builtins.pyi` definitions are cyclic.
To test this, I added a comprehensive corpus of test snippets sourced
from Cinder under [MIT
license](https://github.com/facebookincubator/cinder/blob/cinder/3.10/cinderx/LICENSE),
which matches Ruff's license. I also added to this corpus some
additional snippets for newer language features: all the
`27_func_generic_*` and `73_class_generic_*` files, as well as
`20_lambda_default_arg.py`, and added a test which runs semantic-lint
over all these files. (The test doesn't assert the test-corpus files are
lint-free; just that they are able to lint without a panic.)
Add support for while-loop control flow.
This doesn't yet include general support for terminals and reachability;
that is wider than just while loops and belongs in its own PR.
This also doesn't yet add support for cyclic definitions in loops; that
comes with enough of its own complexity in Salsa that I want to handle
it separately.
Add a lint rule to detect if a name is definitely or possibly undefined
at a given usage.
If I create the file `undef/main.py` with contents:
```python
x = int
def foo():
z
return x
if flag:
y = x
y
```
And then run `cargo run --bin red_knot -- --current-directory
../ruff-examples/undef`, I get the output:
```
Name 'z' used when not defined.
Name 'flag' used when not defined.
Name 'y' used when possibly not defined.
```
If I modify the file to add `y = 0` at the top, red-knot re-checks it
and I get the new output:
```
Name 'z' used when not defined.
Name 'flag' used when not defined.
```
Note that `int` is not flagged, since it's a builtin, and `return x` in
the function scope is not flagged, since it refers to the global `x`.
When poring over traces, the ones that just include a definition or
symbol or expression ID aren't very useful, because you don't know which
file it comes from. This adds that information to the trace.
I guess the downside here is that if calling `.file(db)` on a
scope/definition/expression would execute other traced code, it would be
marked as outside the span? I don't think that's a concern, because I
don't think a simple field access on a tracked struct should ever
execute our code. If I'm wrong and this is a problem, it seems like the
tracing crate has this feature where you can record a field as
`tracing::field::Empty` and then fill in its value later with
`span.record(...)`, but when I tried this it wasn't working for me, not
sure why.
I think there's a lot more we can do to make our tracing output more
useful for debugging (e.g. record an event whenever a
definition/symbol/expression/use id is created with the details of that
definition/symbol/expression/use), this is just dipping my toes in the
water.
Per comments in https://github.com/astral-sh/ruff/pull/12269, "module
global" is kind of long, and arguably redundant.
I tried just using "module" but there were too many cases where I felt
this was ambiguous. I like the way "global" works out better, though it
does require an understanding that in Python "global" generally means
"module global" not "globally global" (though in a sense module globals
are also globally global since modules are singletons).
Support falling back to a global name lookup if a name isn't defined in
the local scope, in the cases where that is correct according to Python
semantics.
In class scopes, a name lookup checks the local namespace first, and if
the name isn't found there, looks it up in globals.
In function scopes (and type parameter scopes, which are function-like),
if a name has any definitions in the local scope, it is a local, and
accessing it when none of those definitions have executed yet just
results in an `UnboundLocalError`, it does not fall back to a global. If
the name does not have any definitions in the local scope, then it is an
implicit global.
Public symbol type lookups never include such a fall back. For example,
if a name is not defined in a class scope, it is not available as a
member on that class, even if a name lookup within the class scope would
have fallen back to a global lookup.
This PR makes the `@override` lint rule work again.
Not yet included/supported in this PR:
* Support for free variables / closures: a free symbol in a nested
function-like scope referring to a symbol in an outer function-like
scope.
* Support for `global` and `nonlocal` statements, which force a symbol
to be treated as global or nonlocal even if it has definitions in the
local scope.
* Module-global lookups should fall back to builtins if the name isn't
found in the module scope.
I would like to expose nicer APIs for the various kinds of symbols
(explicit global, implicit global, free, etc), but this will also wait
for a later PR, when more kinds of symbols are supported.
Adds inference tests sufficient to give full test coverage of the
`UseDefMapBuilder::merge` method.
In the process I realized that we could implement visiting of if
statements in `SemanticBuilder` with fewer `snapshot`, `restore`, and
`merge` operations, so I restructured that visit a bit.
I also found one correctness bug in the `merge` method (it failed to
extend the given snapshot with "unbound" for any missing symbols,
meaning we would just lose the fact that the symbol could be unbound in
the merged-in path), and two efficiency bugs (if one of the ranges to
merge is empty, we can just use the other one, no need for copies, and
if the ranges are overlapping -- which can occur with nested branches --
we can still just merge them with no copies), and fixed all three.
Improve semantic index tests with better assertions than just `.len()`,
and re-add use-definition test that was commented out in the switch to
Salsa initially.
Implements definition-level type inference, with basic control flow
(only if statements and if expressions so far) in Salsa.
There are a couple key ideas here:
1) We can do type inference queries at any of three region
granularities: an entire scope, a single definition, or a single
expression. These are represented by the `InferenceRegion` enum, and the
entry points are the salsa queries `infer_scope_types`,
`infer_definition_types`, and `infer_expression_types`. Generally
per-scope will be used for scopes that we are directly checking and
per-definition will be used anytime we are looking up symbol types from
another module/scope. Per-expression should be uncommon: used only for
the RHS of an unpacking or multi-target assignment (to avoid
re-inferring the RHS once per symbol defined in the assignment) and for
test nodes in type narrowing (e.g. the `test` of an `If` node). All
three queries return a `TypeInference` with a map of types for all
definitions and expressions within their region. If you do e.g.
scope-level inference, when it hits a definition, or an
independently-inferable expression, it should use the relevant query
(which may already be cached) to get all types within the smaller
region. This avoids double-inferring smaller regions, even though larger
regions encompass smaller ones.
2) Instead of building a control-flow graph and lazily traversing it to
find definitions which reach a use of a name (which is O(n^2) in the
worst case), instead semantic indexing builds a use-def map, where every
use of a name knows which definitions can reach that use. We also no
longer track all definitions of a symbol in the symbol itself; instead
the use-def map also records which defs remain visible at the end of the
scope, and considers these the publicly-visible definitions of the
symbol (see below).
Major items left as TODOs in this PR, to be done in follow-up PRs:
1) Free/global references aren't supported yet (only lookup based on
definitions in current scope), which means the override-check example
doesn't currently work. This is the first thing I'll fix as follow-up to
this PR.
2) Control flow outside of if statements and expressions.
3) Type narrowing.
There are also some smaller relevant changes here:
1) Eliminate `Option` in the return type of member lookups; instead
always return `Type::Unbound` for a name we can't find. Also use
`Type::Unbound` for modules we can't resolve (not 100% sure about this
one yet.)
2) Eliminate the use of the terms "public" and "root" to refer to
module-global scope or symbols. Instead consistently use the term
"module-global". It's longer, but it's the clearest, and the most
consistent with typical Python terminology. In particular I don't like
"public" for this use because it has other implications around author
intent (is an underscore-prefixed module-global symbol "public"?). And
"root" is just not commonly used for this in Python.
3) Eliminate the `PublicSymbol` Salsa ingredient. Many non-module-global
symbols can also be seen from other scopes (e.g. by a free var in a
nested scope, or by class attribute access), and thus need to have a
"public type" (that is, the type not as seen from a particular use in
the control flow of the same scope, but the type as seen from some other
scope.) So all symbols need to have a "public type" (here I want to keep
the use of the term "public", unless someone has a better term to
suggest -- since it's "public type of a symbol" and not "public symbol"
the confusion with e.g. initial underscores is less of an issue.) At
least initially, I would like to try not having special handling for
module-global symbols vs other symbols.
4) Switch to using "definitions that reach end of scope" rather than
"all definitions" in determining the public type of a symbol. I'm
convinced that in general this is the right way to go. We may want to
refine this further in future for some free-variable cases, but it can
be changed purely by making changes to the building of the use-def map
(the `public_definitions` index in it), without affecting any other
code. One consequence of combining this with no control-flow support
(just last-definition-wins) is that some inference tests now give more
wrong-looking results; I left TODO comments on these tests to fix them
when control flow is added.
And some potential areas for consideration in the future:
1) Should `symbol_ty` be a Salsa query? This would require making all
symbols a Salsa ingredient, and tracking even more dependencies. But it
would save some repeated reconstruction of unions, for symbols with
multiple public definitions. For now I'm not making it a query, but open
to changing this in future with actual perf evidence that it's better.
Intern types using Salsa interning instead of in the `TypeInference`
result.
This eliminates the need for `TypingContext`, and also paves the way for
finer-grained type inference queries.
Alex Waygood
Dhruv Manilawala
Carl Meyer
Simon
Micha Reiser
Dylan
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