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[red-knot] Allow explicit specialization of generic classes (#17023) 

This PR lets you explicitly specialize a generic class using a subscript
expression. It introduces three new Rust types for representing classes:

- `NonGenericClass`
- `GenericClass` (not specialized)
- `GenericAlias` (specialized)

and two enum wrappers:

- `ClassType` (a non-generic class or generic alias, represents a class
_type_ at runtime)
- `ClassLiteralType` (a non-generic class or generic class, represents a
class body in the AST)

We also add internal support for specializing callables, in particular
function literals. (That is, the internal `Type` representation now
attaches an optional specialization to a function literal.) This is used
in this PR for the methods of a generic class, but should also give us
most of what we need for specializing generic _functions_ (which this PR
does not yet tackle).

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
This commit is contained in:
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122
crates/red_knot_python_semantic/resources/mdtest/generics/classes.md
View File

@ -13,8 +13,6 @@ class C[T]: ...
A class that inherits from a generic class, and fills its type parameters with typevars, is generic:
```py
# TODO: no error
# error: [non-subscriptable]
class D[U](C[U]): ...
```
@ -22,8 +20,6 @@ A class that inherits from a generic class, but fills its type parameters with c
_not_ generic:
```py
# TODO: no error
# error: [non-subscriptable]
class E(C[int]): ...
```
@ -57,7 +53,7 @@ class D(C[T]): ...
(Examples `E` and `F` from above do not have analogues in the legacy syntax.)
## Inferring generic class parameters
## Specializing generic classes explicitly
The type parameter can be specified explicitly:
@ -65,25 +61,77 @@ The type parameter can be specified explicitly:
class C[T]:
x: T
# TODO: no error
# TODO: revealed: C[int]
# error: [non-subscriptable]
reveal_type(C[int]()) # revealed: C
reveal_type(C[int]()) # revealed: C[int]
```
The specialization must match the generic types:
```py
# error: [too-many-positional-arguments] "Too many positional arguments to class `C`: expected 1, got 2"
reveal_type(C[int, int]()) # revealed: Unknown
```
If the type variable has an upper bound, the specialized type must satisfy that bound:
```py
class Bounded[T: int]: ...
class BoundedByUnion[T: int | str]: ...
class IntSubclass(int): ...
reveal_type(Bounded[int]()) # revealed: Bounded[int]
reveal_type(Bounded[IntSubclass]()) # revealed: Bounded[IntSubclass]
# error: [invalid-argument-type] "Object of type `str` cannot be assigned to parameter 1 (`T`) of class `Bounded`; expected type `int`"
reveal_type(Bounded[str]()) # revealed: Unknown
# error: [invalid-argument-type] "Object of type `int | str` cannot be assigned to parameter 1 (`T`) of class `Bounded`; expected type `int`"
reveal_type(Bounded[int | str]()) # revealed: Unknown
reveal_type(BoundedByUnion[int]()) # revealed: BoundedByUnion[int]
reveal_type(BoundedByUnion[IntSubclass]()) # revealed: BoundedByUnion[IntSubclass]
reveal_type(BoundedByUnion[str]()) # revealed: BoundedByUnion[str]
reveal_type(BoundedByUnion[int | str]()) # revealed: BoundedByUnion[int | str]
```
If the type variable is constrained, the specialized type must satisfy those constraints:
```py
class Constrained[T: (int, str)]: ...
reveal_type(Constrained[int]()) # revealed: Constrained[int]
# TODO: error: [invalid-argument-type]
# TODO: revealed: Constrained[Unknown]
reveal_type(Constrained[IntSubclass]()) # revealed: Constrained[IntSubclass]
reveal_type(Constrained[str]()) # revealed: Constrained[str]
# TODO: error: [invalid-argument-type]
# TODO: revealed: Unknown
reveal_type(Constrained[int | str]()) # revealed: Constrained[int | str]
# error: [invalid-argument-type] "Object of type `object` cannot be assigned to parameter 1 (`T`) of class `Constrained`; expected type `int | str`"
reveal_type(Constrained[object]()) # revealed: Unknown
```
## Inferring generic class parameters
We can infer the type parameter from a type context:
```py
class C[T]:
x: T
c: C[int] = C()
# TODO: revealed: C[int]
reveal_type(c) # revealed: C
reveal_type(c) # revealed: C[Unknown]
```
The typevars of a fully specialized generic class should no longer be visible:
```py
# TODO: revealed: int
reveal_type(c.x) # revealed: T
reveal_type(c.x) # revealed: Unknown
```
If the type parameter is not specified explicitly, and there are no constraints that let us infer a
@ -92,15 +140,13 @@ specific type, we infer the typevar's default type:
```py
class D[T = int]: ...
# TODO: revealed: D[int]
reveal_type(D()) # revealed: D
reveal_type(D()) # revealed: D[int]
```
If a typevar does not provide a default, we use `Unknown`:
```py
# TODO: revealed: C[Unknown]
reveal_type(C()) # revealed: C
reveal_type(C()) # revealed: C[Unknown]
```
If the type of a constructor parameter is a class typevar, we can use that to infer the type
@ -111,17 +157,14 @@ class E[T]:
def __init__(self, x: T) -> None: ...
# TODO: revealed: E[int] or E[Literal[1]]
# TODO should not emit an error
# error: [invalid-argument-type] "Object of type `Literal[1]` cannot be assigned to parameter 2 (`x`) of bound method `__init__`; expected type `T`"
reveal_type(E(1)) # revealed: E
reveal_type(E(1)) # revealed: E[Unknown]
```
The types inferred from a type context and from a constructor parameter must be consistent with each
other:
```py
# TODO: the error should not leak the `T` typevar and should mention `E[int]`
# error: [invalid-argument-type] "Object of type `Literal["five"]` cannot be assigned to parameter 2 (`x`) of bound method `__init__`; expected type `T`"
# TODO: error: [invalid-argument-type]
wrong_innards: E[int] = E("five")
```
@ -134,17 +177,33 @@ propagate through:
class Base[T]:
x: T | None = None
# TODO: no error
# error: [non-subscriptable]
class Sub[U](Base[U]): ...
reveal_type(Base[int].x) # revealed: int | None
reveal_type(Sub[int].x) # revealed: int | None
```
## Generic methods
Generic classes can contain methods that are themselves generic. The generic methods can refer to
the typevars of the enclosing generic class, and introduce new (distinct) typevars that are only in
scope for the method.
```py
class C[T]:
def method[U](self, u: U) -> U:
return u
# error: [unresolved-reference]
def cannot_use_outside_of_method(self, u: U): ...
# TODO: error
def cannot_shadow_class_typevar[T](self, t: T): ...
c: C[int] = C[int]()
# TODO: no error
# TODO: revealed: int | None
# error: [non-subscriptable]
reveal_type(Base[int].x) # revealed: T | None
# TODO: revealed: int | None
# error: [non-subscriptable]
reveal_type(Sub[int].x) # revealed: T | None
# TODO: revealed: str or Literal["string"]
# error: [invalid-argument-type]
reveal_type(c.method("string")) # revealed: U
```
## Cyclic class definition
@ -158,8 +217,6 @@ Here, `Sub` is not a generic class, since it fills its superclass's type paramet
```pyi
class Base[T]: ...
# TODO: no error
# error: [non-subscriptable]
class Sub(Base[Sub]): ...
reveal_type(Sub) # revealed: Literal[Sub]
@ -171,9 +228,6 @@ A similar case can work in a non-stub file, if forward references are stringifie
```py
class Base[T]: ...
# TODO: no error
# error: [non-subscriptable]
class Sub(Base["Sub"]): ...
reveal_type(Sub) # revealed: Literal[Sub]
@ -186,8 +240,6 @@ In a non-stub file, without stringified forward references, this raises a `NameE
```py
class Base[T]: ...
# TODO: the unresolved-reference error is correct, the non-subscriptable is not
# error: [non-subscriptable]
# error: [unresolved-reference]
class Sub(Base[Sub]): ...
```

48
crates/red_knot_python_semantic/resources/mdtest/generics/scoping.md
View File

@ -82,18 +82,51 @@ class C[T]:
def m2(self, x: T) -> T:
return x
c: C[int] = C()
# TODO: no error
# error: [invalid-argument-type]
c: C[int] = C[int]()
c.m1(1)
# TODO: no error
# error: [invalid-argument-type]
c.m2(1)
# TODO: expected type `int`
# error: [invalid-argument-type] "Object of type `Literal["string"]` cannot be assigned to parameter 2 (`x`) of bound method `m2`; expected type `T`"
# error: [invalid-argument-type] "Object of type `Literal["string"]` cannot be assigned to parameter 2 (`x`) of bound method `m2`; expected type `int`"
c.m2("string")
```
## Functions on generic classes are descriptors
This repeats the tests in the [Functions as descriptors](./call/methods.md) test suite, but on a
generic class. This ensures that we are carrying any specializations through the entirety of the
descriptor protocol, which is how `self` parameters are bound to instance methods.
```py
from inspect import getattr_static
class C[T]:
def f(self, x: T) -> str:
return "a"
reveal_type(getattr_static(C[int], "f")) # revealed: Literal[f[int]]
reveal_type(getattr_static(C[int], "f").__get__) # revealed: <method-wrapper `__get__` of `f[int]`>
reveal_type(getattr_static(C[int], "f").__get__(None, C[int])) # revealed: Literal[f[int]]
# revealed: <bound method `f` of `C[int]`>
reveal_type(getattr_static(C[int], "f").__get__(C[int](), C[int]))
reveal_type(C[int].f) # revealed: Literal[f[int]]
reveal_type(C[int]().f) # revealed: <bound method `f` of `C[int]`>
bound_method = C[int]().f
reveal_type(bound_method.__self__) # revealed: C[int]
reveal_type(bound_method.__func__) # revealed: Literal[f[int]]
reveal_type(C[int]().f(1)) # revealed: str
reveal_type(bound_method(1)) # revealed: str
C[int].f(1) # error: [missing-argument]
reveal_type(C[int].f(C[int](), 1)) # revealed: str
class D[U](C[U]):
pass
reveal_type(D[int]().f) # revealed: <bound method `f` of `D[int]`>
```
## Methods can mention other typevars
> A type variable used in a method that does not match any of the variables that parameterize the
@ -127,7 +160,6 @@ c: C[int] = C()
# TODO: no errors
# TODO: revealed: str
# error: [invalid-argument-type]
# error: [invalid-argument-type]
reveal_type(c.m(1, "string")) # revealed: S
```

18
crates/red_knot_python_semantic/resources/mdtest/narrow/type.md
View File

@ -109,6 +109,24 @@ def _(x: A | B):
reveal_type(x) # revealed: A
```
## Narrowing for generic classes
Note that `type` returns the runtime class of an object, which does _not_ include specializations in
the case of a generic class. (The typevars are erased.) That means we cannot narrow the type to the
specialization that we compare with; we must narrow to an unknown specialization of the generic
class.
```py
class A[T = int]: ...
class B: ...
def _[T](x: A | B):
if type(x) is A[str]:
reveal_type(x) # revealed: A[int] & A[Unknown] | B & A[Unknown]
else:
reveal_type(x) # revealed: A[int] | B
```
## Limitations
```py

5
crates/red_knot_python_semantic/resources/mdtest/stubs/class.md
View File

@ -8,13 +8,10 @@ In type stubs, classes can reference themselves in their base class definitions.
```pyi
class Foo[T]: ...
# TODO: actually is subscriptable
# error: [non-subscriptable]
class Bar(Foo[Bar]): ...
reveal_type(Bar) # revealed: Literal[Bar]
# TODO: Instead of `Literal[Foo]`, we might eventually want to show a type that involves the type parameter.
reveal_type(Bar.__mro__) # revealed: tuple[Literal[Bar], Literal[Foo], Literal[object]]
reveal_type(Bar.__mro__) # revealed: tuple[Literal[Bar], Literal[Foo[Bar]], Literal[object]]
```
## Access to attributes declared in stubs

11
crates/red_knot_python_semantic/src/symbol.rs
View File

@ -425,6 +425,17 @@ impl<'db> SymbolAndQualifiers<'db> {
self.qualifiers.contains(TypeQualifiers::CLASS_VAR)
}
#[must_use]
pub(crate) fn map_type(
self,
f: impl FnOnce(Type<'db>) -> Type<'db>,
) -> SymbolAndQualifiers<'db> {
SymbolAndQualifiers {
symbol: self.symbol.map_type(f),
qualifiers: self.qualifiers,
}
}
/// Transform symbol and qualifiers into a [`LookupResult`],
/// a [`Result`] type in which the `Ok` variant represents a definitely bound symbol
/// and the `Err` variant represents a symbol that is either definitely or possibly unbound.

372
crates/red_knot_python_semantic/src/types.rs
View File

@ -35,12 +35,16 @@ use crate::symbol::{imported_symbol, Boundness, Symbol, SymbolAndQualifiers};
use crate::types::call::{Bindings, CallArgumentTypes};
pub(crate) use crate::types::class_base::ClassBase;
use crate::types::diagnostic::{INVALID_TYPE_FORM, UNSUPPORTED_BOOL_CONVERSION};
use crate::types::generics::Specialization;
use crate::types::infer::infer_unpack_types;
use crate::types::mro::{Mro, MroError, MroIterator};
pub(crate) use crate::types::narrow::infer_narrowing_constraint;
use crate::types::signatures::{Parameter, ParameterForm, ParameterKind, Parameters};
use crate::{Db, FxOrderSet, Module, Program};
pub(crate) use class::{Class, ClassLiteralType, InstanceType, KnownClass, KnownInstanceType};
pub(crate) use class::{
Class, ClassLiteralType, ClassType, GenericAlias, GenericClass, InstanceType, KnownClass,
KnownInstanceType, NonGenericClass,
};
mod builder;
mod call;
@ -49,6 +53,7 @@ mod class_base;
mod context;
mod diagnostic;
mod display;
mod generics;
mod infer;
mod mro;
mod narrow;
@ -276,6 +281,18 @@ pub struct PropertyInstanceType<'db> {
setter: Option<Type<'db>>,
}
impl<'db> PropertyInstanceType<'db> {
fn apply_specialization(self, db: &'db dyn Db, specialization: Specialization<'db>) -> Self {
let getter = self
.getter(db)
.map(|ty| ty.apply_specialization(db, specialization));
let setter = self
.setter(db)
.map(|ty| ty.apply_specialization(db, specialization));
Self::new(db, getter, setter)
}
}
/// Representation of a type: a set of possible values at runtime.
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, salsa::Update)]
pub enum Type<'db> {
@ -319,7 +336,9 @@ pub enum Type<'db> {
ModuleLiteral(ModuleLiteralType<'db>),
/// A specific class object
ClassLiteral(ClassLiteralType<'db>),
// The set of all class objects that are subclasses of the given class (C), spelled `type[C]`.
/// A specialization of a generic class
GenericAlias(GenericAlias<'db>),
/// The set of all class objects that are subclasses of the given class (C), spelled `type[C]`.
SubclassOf(SubclassOfType<'db>),
/// The set of Python objects with the given class in their __class__'s method resolution order
Instance(InstanceType<'db>),
@ -382,20 +401,17 @@ impl<'db> Type<'db> {
fn is_none(&self, db: &'db dyn Db) -> bool {
self.into_instance()
.is_some_and(|instance| instance.class().is_known(db, KnownClass::NoneType))
.is_some_and(|instance| instance.class.is_known(db, KnownClass::NoneType))
}
pub fn is_notimplemented(&self, db: &'db dyn Db) -> bool {
self.into_instance().is_some_and(|instance| {
instance
.class()
.is_known(db, KnownClass::NotImplementedType)
})
self.into_instance()
.is_some_and(|instance| instance.class.is_known(db, KnownClass::NotImplementedType))
}
pub fn is_object(&self, db: &'db dyn Db) -> bool {
self.into_instance()
.is_some_and(|instance| instance.class().is_object(db))
.is_some_and(|instance| instance.class.is_object(db))
}
pub const fn is_todo(&self) -> bool {
@ -426,6 +442,12 @@ impl<'db> Type<'db> {
| Self::WrapperDescriptor(_)
| Self::MethodWrapper(_) => false,
Self::GenericAlias(generic) => generic
.specialization(db)
.types(db)
.iter()
.any(|ty| ty.contains_todo(db)),
Self::Callable(callable) => {
let signature = callable.signature(db);
signature.parameters().iter().any(|param| {
@ -467,10 +489,6 @@ impl<'db> Type<'db> {
}
}
pub const fn class_literal(class: Class<'db>) -> Self {
Self::ClassLiteral(ClassLiteralType { class })
}
pub const fn into_class_literal(self) -> Option<ClassLiteralType<'db>> {
match self {
Type::ClassLiteral(class_type) => Some(class_type),
@ -492,6 +510,29 @@ impl<'db> Type<'db> {
matches!(self, Type::ClassLiteral(..))
}
pub const fn into_class_type(self) -> Option<ClassType<'db>> {
match self {
Type::ClassLiteral(ClassLiteralType::NonGeneric(non_generic)) => {
Some(ClassType::NonGeneric(non_generic))
}
Type::GenericAlias(alias) => Some(ClassType::Generic(alias)),
_ => None,
}
}
#[track_caller]
pub fn expect_class_type(self) -> ClassType<'db> {
self.into_class_type()
.expect("Expected a Type::GenericAlias or non-generic Type::ClassLiteral variant")
}
pub const fn is_class_type(&self) -> bool {
matches!(
self,
Type::ClassLiteral(ClassLiteralType::NonGeneric(_)) | Type::GenericAlias(_)
)
}
pub const fn is_instance(&self) -> bool {
matches!(self, Type::Instance(..))
}
@ -631,7 +672,7 @@ impl<'db> Type<'db> {
matches!(self, Type::LiteralString)
}
pub const fn instance(class: Class<'db>) -> Self {
pub const fn instance(class: ClassType<'db>) -> Self {
Self::Instance(InstanceType { class })
}
@ -693,6 +734,10 @@ impl<'db> Type<'db> {
| Type::KnownInstance(_)
| Type::IntLiteral(_)
| Type::SubclassOf(_) => self,
Type::GenericAlias(generic) => {
let specialization = generic.specialization(db).normalized(db);
Type::GenericAlias(GenericAlias::new(db, generic.origin(db), specialization))
}
Type::TypeVar(typevar) => match typevar.bound_or_constraints(db) {
Some(TypeVarBoundOrConstraints::UpperBound(bound)) => {
Type::TypeVar(TypeVarInstance::new(
@ -932,13 +977,16 @@ impl<'db> Type<'db> {
// `Literal[<class 'C'>]` is a subtype of `type[B]` if `C` is a subclass of `B`,
// since `type[B]` describes all possible runtime subclasses of the class object `B`.
(
Type::ClassLiteral(ClassLiteralType { class }),
Type::SubclassOf(target_subclass_ty),
) => target_subclass_ty
(Type::ClassLiteral(class), Type::SubclassOf(target_subclass_ty)) => target_subclass_ty
.subclass_of()
.into_class()
.is_some_and(|target_class| class.is_subclass_of(db, target_class)),
.is_some_and(|target_class| class.is_subclass_of(db, None, target_class)),
(Type::GenericAlias(alias), Type::SubclassOf(target_subclass_ty)) => target_subclass_ty
.subclass_of()
.into_class()
.is_some_and(|target_class| {
ClassType::from(alias).is_subclass_of(db, target_class)
}),
// This branch asks: given two types `type[T]` and `type[S]`, is `type[T]` a subtype of `type[S]`?
(Type::SubclassOf(self_subclass_ty), Type::SubclassOf(target_subclass_ty)) => {
@ -948,9 +996,12 @@ impl<'db> Type<'db> {
// `Literal[str]` is a subtype of `type` because the `str` class object is an instance of its metaclass `type`.
// `Literal[abc.ABC]` is a subtype of `abc.ABCMeta` because the `abc.ABC` class object
// is an instance of its metaclass `abc.ABCMeta`.
(Type::ClassLiteral(ClassLiteralType { class }), _) => {
(Type::ClassLiteral(class), _) => {
class.metaclass_instance_type(db).is_subtype_of(db, target)
}
(Type::GenericAlias(alias), _) => ClassType::from(alias)
.metaclass_instance_type(db)
.is_subtype_of(db, target),
// `type[str]` (== `SubclassOf("str")` in red-knot) describes all possible runtime subclasses
// of the class object `str`. It is a subtype of `type` (== `Instance("type")`) because `str`
@ -1141,11 +1192,10 @@ impl<'db> Type<'db> {
// Every class literal type is also assignable to `type[Any]`, because the class
// literal type for a class `C` is a subtype of `type[C]`, and `type[C]` is assignable
// to `type[Any]`.
(Type::ClassLiteral(_) | Type::SubclassOf(_), Type::SubclassOf(target_subclass_of))
if target_subclass_of.is_dynamic() =>
{
true
}
(
Type::ClassLiteral(_) | Type::GenericAlias(_) | Type::SubclassOf(_),
Type::SubclassOf(target_subclass_of),
) if target_subclass_of.is_dynamic() => true,
// `type[Any]` is assignable to any type that `type[object]` is assignable to, because
// `type[Any]` can materialize to `type[object]`.
@ -1386,6 +1436,7 @@ impl<'db> Type<'db> {
| Type::WrapperDescriptor(..)
| Type::ModuleLiteral(..)
| Type::ClassLiteral(..)
| Type::GenericAlias(..)
| Type::KnownInstance(..)),
right @ (Type::BooleanLiteral(..)
| Type::IntLiteral(..)
@ -1398,6 +1449,7 @@ impl<'db> Type<'db> {
| Type::WrapperDescriptor(..)
| Type::ModuleLiteral(..)
| Type::ClassLiteral(..)
| Type::GenericAlias(..)
| Type::KnownInstance(..)),
) => left != right,
@ -1406,6 +1458,7 @@ impl<'db> Type<'db> {
(
Type::Tuple(..),
Type::ClassLiteral(..)
| Type::GenericAlias(..)
| Type::ModuleLiteral(..)
| Type::BooleanLiteral(..)
| Type::BytesLiteral(..)
@ -1420,6 +1473,7 @@ impl<'db> Type<'db> {
)
| (
Type::ClassLiteral(..)
| Type::GenericAlias(..)
| Type::ModuleLiteral(..)
| Type::BooleanLiteral(..)
| Type::BytesLiteral(..)
@ -1434,17 +1488,23 @@ impl<'db> Type<'db> {
Type::Tuple(..),
) => true,
(
Type::SubclassOf(subclass_of_ty),
Type::ClassLiteral(ClassLiteralType { class: class_b }),
)
| (
Type::ClassLiteral(ClassLiteralType { class: class_b }),
Type::SubclassOf(subclass_of_ty),
) => match subclass_of_ty.subclass_of() {
ClassBase::Dynamic(_) => false,
ClassBase::Class(class_a) => !class_b.is_subclass_of(db, class_a),
},
(Type::SubclassOf(subclass_of_ty), Type::ClassLiteral(class_b))
| (Type::ClassLiteral(class_b), Type::SubclassOf(subclass_of_ty)) => {
match subclass_of_ty.subclass_of() {
ClassBase::Dynamic(_) => false,
ClassBase::Class(class_a) => !class_b.is_subclass_of(db, None, class_a),
}
}
(Type::SubclassOf(subclass_of_ty), Type::GenericAlias(alias_b))
| (Type::GenericAlias(alias_b), Type::SubclassOf(subclass_of_ty)) => {
match subclass_of_ty.subclass_of() {
ClassBase::Dynamic(_) => false,
ClassBase::Class(class_a) => {
!ClassType::from(alias_b).is_subclass_of(db, class_a)
}
}
}
(
Type::SubclassOf(_),
@ -1561,12 +1621,14 @@ impl<'db> Type<'db> {
// A class-literal type `X` is always disjoint from an instance type `Y`,
// unless the type expressing "all instances of `Z`" is a subtype of of `Y`,
// where `Z` is `X`'s metaclass.
(Type::ClassLiteral(ClassLiteralType { class }), instance @ Type::Instance(_))
| (instance @ Type::Instance(_), Type::ClassLiteral(ClassLiteralType { class })) => {
!class
.metaclass_instance_type(db)
.is_subtype_of(db, instance)
}
(Type::ClassLiteral(class), instance @ Type::Instance(_))
| (instance @ Type::Instance(_), Type::ClassLiteral(class)) => !class
.metaclass_instance_type(db)
.is_subtype_of(db, instance),
(Type::GenericAlias(alias), instance @ Type::Instance(_))
| (instance @ Type::Instance(_), Type::GenericAlias(alias)) => !ClassType::from(alias)
.metaclass_instance_type(db)
.is_subtype_of(db, instance),
(Type::FunctionLiteral(..), Type::Instance(InstanceType { class }))
| (Type::Instance(InstanceType { class }), Type::FunctionLiteral(..)) => {
@ -1692,7 +1754,7 @@ impl<'db> Type<'db> {
},
Type::SubclassOf(subclass_of_ty) => subclass_of_ty.is_fully_static(),
Type::ClassLiteral(_) | Type::Instance(_) => {
Type::ClassLiteral(_) | Type::GenericAlias(_) | Type::Instance(_) => {
// TODO: Ideally, we would iterate over the MRO of the class, check if all
// bases are fully static, and only return `true` if that is the case.
//
@ -1763,6 +1825,7 @@ impl<'db> Type<'db> {
| Type::FunctionLiteral(..)
| Type::WrapperDescriptor(..)
| Type::ClassLiteral(..)
| Type::GenericAlias(..)
| Type::ModuleLiteral(..)
| Type::KnownInstance(..) => true,
Type::Callable(_) => {
@ -1828,6 +1891,7 @@ impl<'db> Type<'db> {
| Type::MethodWrapper(_)
| Type::ModuleLiteral(..)
| Type::ClassLiteral(..)
| Type::GenericAlias(..)
| Type::IntLiteral(..)
| Type::BooleanLiteral(..)
| Type::StringLiteral(..)
@ -1912,7 +1976,7 @@ impl<'db> Type<'db> {
Type::Dynamic(_) | Type::Never => Some(Symbol::bound(self).into()),
Type::ClassLiteral(class_literal @ ClassLiteralType { class }) => {
Type::ClassLiteral(class) => {
match (class.known(db), name) {
(Some(KnownClass::FunctionType), "__get__") => Some(
Symbol::bound(Type::WrapperDescriptor(
@ -1956,10 +2020,14 @@ impl<'db> Type<'db> {
"__get__" | "__set__" | "__delete__",
) => Some(Symbol::Unbound.into()),
_ => Some(class_literal.class_member(db, name, policy)),
_ => Some(class.class_member(db, None, name, policy)),
}
}
Type::GenericAlias(alias) => {
Some(ClassType::from(*alias).class_member(db, name, policy))
}
Type::SubclassOf(subclass_of)
if name == "__get__"
&& matches!(
@ -2126,7 +2194,9 @@ impl<'db> Type<'db> {
// a `__dict__` that is filled with class level attributes. Modeling this is currently not
// required, as `instance_member` is only called for instance-like types through `member`,
// but we might want to add this in the future.
Type::ClassLiteral(_) | Type::SubclassOf(_) => Symbol::Unbound.into(),
Type::ClassLiteral(_) | Type::GenericAlias(_) | Type::SubclassOf(_) => {
Symbol::Unbound.into()
}
}
}
@ -2439,7 +2509,7 @@ impl<'db> Type<'db> {
)
.into(),
Type::ClassLiteral(ClassLiteralType { class })
Type::ClassLiteral(class)
if name == "__get__" && class.is_known(db, KnownClass::FunctionType) =>
{
Symbol::bound(Type::WrapperDescriptor(
@ -2447,7 +2517,7 @@ impl<'db> Type<'db> {
))
.into()
}
Type::ClassLiteral(ClassLiteralType { class })
Type::ClassLiteral(class)
if name == "__get__" && class.is_known(db, KnownClass::Property) =>
{
Symbol::bound(Type::WrapperDescriptor(
@ -2455,7 +2525,7 @@ impl<'db> Type<'db> {
))
.into()
}
Type::ClassLiteral(ClassLiteralType { class })
Type::ClassLiteral(class)
if name == "__set__" && class.is_known(db, KnownClass::Property) =>
{
Symbol::bound(Type::WrapperDescriptor(
@ -2599,8 +2669,8 @@ impl<'db> Type<'db> {
}
}
Type::ClassLiteral(..) | Type::SubclassOf(..) => {
let class_attr_plain = self.find_name_in_mro_with_policy(db, name_str, policy).expect(
Type::ClassLiteral(..) | Type::GenericAlias(..) | Type::SubclassOf(..) => {
let class_attr_plain = self.find_name_in_mro_with_policy(db, name_str,policy).expect(
"Calling `find_name_in_mro` on class literals and subclass-of types should always return `Some`",
);
@ -2785,14 +2855,17 @@ impl<'db> Type<'db> {
Type::AlwaysFalsy => Truthiness::AlwaysFalse,
Type::ClassLiteral(ClassLiteralType { class }) => class
Type::ClassLiteral(class) => class
.metaclass_instance_type(db)
.try_bool_impl(db, allow_short_circuit)?,
Type::GenericAlias(alias) => ClassType::from(*alias)
.metaclass_instance_type(db)
.try_bool_impl(db, allow_short_circuit)?,
Type::SubclassOf(subclass_of_ty) => match subclass_of_ty.subclass_of() {
ClassBase::Dynamic(_) => Truthiness::Ambiguous,
ClassBase::Class(class) => {
Type::class_literal(class).try_bool_impl(db, allow_short_circuit)?
Type::from(class).try_bool_impl(db, allow_short_circuit)?
}
},
@ -3141,7 +3214,7 @@ impl<'db> Type<'db> {
)),
},
Type::ClassLiteral(ClassLiteralType { class }) => match class.known(db) {
Type::ClassLiteral(class) => match class.known(db) {
// TODO: Ideally we'd use `try_call_constructor` for all constructor calls.
// Currently we don't for a few special known types, either because their
// constructors are defined with overloads, or because we want to special case
@ -3345,13 +3418,23 @@ impl<'db> Type<'db> {
}
},
Type::GenericAlias(_) => {
// TODO annotated return type on `__new__` or metaclass `__call__`
// TODO check call vs signatures of `__new__` and/or `__init__`
let signature = CallableSignature::single(
self,
Signature::new(Parameters::gradual_form(), self.to_instance(db)),
);
Signatures::single(signature)
}
Type::SubclassOf(subclass_of_type) => match subclass_of_type.subclass_of() {
ClassBase::Dynamic(dynamic_type) => Type::Dynamic(dynamic_type).signatures(db),
// Most type[] constructor calls are handled by `try_call_constructor` and not via
// getting the signature here. This signature can still be used in some cases (e.g.
// evaluating callable subtyping). TODO improve this definition (intersection of
// `__new__` and `__init__` signatures? and respect metaclass `__call__`).
ClassBase::Class(class) => Type::class_literal(class).signatures(db),
ClassBase::Class(class) => Type::from(class).signatures(db),
},
Type::Instance(_) => {
@ -3729,7 +3812,8 @@ impl<'db> Type<'db> {
pub fn to_instance(&self, db: &'db dyn Db) -> Option<Type<'db>> {
match self {
Type::Dynamic(_) | Type::Never => Some(*self),
Type::ClassLiteral(ClassLiteralType { class }) => Some(Type::instance(*class)),
Type::ClassLiteral(class) => Some(Type::instance(class.default_specialization(db))),
Type::GenericAlias(alias) => Some(Type::instance(ClassType::from(*alias))),
Type::SubclassOf(subclass_of_ty) => Some(subclass_of_ty.to_instance()),
Type::Union(union) => {
let mut builder = UnionBuilder::new(db);
@ -3774,7 +3858,7 @@ impl<'db> Type<'db> {
match self {
// Special cases for `float` and `complex`
// https://typing.readthedocs.io/en/latest/spec/special-types.html#special-cases-for-float-and-complex
Type::ClassLiteral(ClassLiteralType { class }) => {
Type::ClassLiteral(class) => {
let ty = match class.known(db) {
Some(KnownClass::Any) => Type::any(),
Some(KnownClass::Complex) => UnionType::from_elements(
@ -3792,10 +3876,11 @@ impl<'db> Type<'db> {
KnownClass::Float.to_instance(db),
],
),
_ => Type::instance(*class),
_ => Type::instance(class.default_specialization(db)),
};
Ok(ty)
}
Type::GenericAlias(alias) => Ok(Type::instance(ClassType::from(*alias))),
Type::SubclassOf(_)
| Type::BooleanLiteral(_)
@ -4033,7 +4118,8 @@ impl<'db> Type<'db> {
}
},
Type::ClassLiteral(ClassLiteralType { class }) => class.metaclass(db),
Type::ClassLiteral(class) => class.metaclass(db),
Type::GenericAlias(alias) => ClassType::from(*alias).metaclass(db),
Type::SubclassOf(subclass_of_ty) => match subclass_of_ty.subclass_of() {
ClassBase::Dynamic(_) => *self,
ClassBase::Class(class) => SubclassOfType::from(
@ -4055,6 +4141,121 @@ impl<'db> Type<'db> {
}
}
/// Applies a specialization to this type, replacing any typevars with the types that they are
/// specialized to.
///
/// Note that this does not specialize generic classes, functions, or type aliases! That is a
/// different operation that is performed explicitly (via a subscript operation), or implicitly
/// via a call to the generic object.
#[must_use]
#[salsa::tracked]
pub fn apply_specialization(
self,
db: &'db dyn Db,
specialization: Specialization<'db>,
) -> Type<'db> {
match self {
Type::TypeVar(typevar) => specialization.get(db, typevar).unwrap_or(self),
Type::FunctionLiteral(function) => {
Type::FunctionLiteral(function.apply_specialization(db, specialization))
}
// Note that we don't need to apply the specialization to `self_instance`, since it
// must either be a non-generic class literal (which cannot have any typevars to
// specialize) or a generic alias (which has already been fully specialized). For a
// generic alias, the specialization being applied here must be for some _other_
// generic context nested within the generic alias's class literal, which the generic
// alias's context cannot refer to. (The _method_ does need to be specialized, since it
// might be a nested generic method, whose generic context is what is now being
// specialized.)
Type::BoundMethod(method) => Type::BoundMethod(BoundMethodType::new(
db,
method.function(db).apply_specialization(db, specialization),
method.self_instance(db),
)),
Type::MethodWrapper(MethodWrapperKind::FunctionTypeDunderGet(function)) => {
Type::MethodWrapper(MethodWrapperKind::FunctionTypeDunderGet(
function.apply_specialization(db, specialization),
))
}
Type::MethodWrapper(MethodWrapperKind::PropertyDunderGet(property)) => {
Type::MethodWrapper(MethodWrapperKind::PropertyDunderGet(
property.apply_specialization(db, specialization),
))
}
Type::MethodWrapper(MethodWrapperKind::PropertyDunderSet(property)) => {
Type::MethodWrapper(MethodWrapperKind::PropertyDunderSet(
property.apply_specialization(db, specialization),
))
}
Type::Callable(callable) => {
Type::Callable(callable.apply_specialization(db, specialization))
}
Type::GenericAlias(generic) => {
let specialization = generic
.specialization(db)
.apply_specialization(db, specialization);
Type::GenericAlias(GenericAlias::new(db, generic.origin(db), specialization))
}
Type::PropertyInstance(property) => {
Type::PropertyInstance(property.apply_specialization(db, specialization))
}
Type::Union(union) => union.map(db, |element| {
element.apply_specialization(db, specialization)
}),
Type::Intersection(intersection) => {
let mut builder = IntersectionBuilder::new(db);
for positive in intersection.positive(db) {
builder =
builder.add_positive(positive.apply_specialization(db, specialization));
}
for negative in intersection.negative(db) {
builder =
builder.add_negative(negative.apply_specialization(db, specialization));
}
builder.build()
}
Type::Tuple(tuple) => TupleType::from_elements(
db,
tuple
.iter(db)
.map(|ty| ty.apply_specialization(db, specialization)),
),
Type::Dynamic(_)
| Type::Never
| Type::AlwaysTruthy
| Type::AlwaysFalsy
| Type::WrapperDescriptor(_)
| Type::ModuleLiteral(_)
// A non-generic class never needs to be specialized. A generic class is specialized
// explicitly (via a subscript expression) or implicitly (via a call), and not because
// some other generic context's specialization is applied to it.
| Type::ClassLiteral(_)
// SubclassOf contains a ClassType, which has already been specialized if needed, like
// above with BoundMethod's self_instance.
| Type::SubclassOf(_)
| Type::IntLiteral(_)
| Type::BooleanLiteral(_)
| Type::LiteralString
| Type::StringLiteral(_)
| Type::BytesLiteral(_)
| Type::SliceLiteral(_)
// Instance contains a ClassType, which has already been specialized if needed, like
// above with BoundMethod's self_instance.
| Type::Instance(_)
| Type::KnownInstance(_) => self,
}
}
/// Return the string representation of this type when converted to string as it would be
/// provided by the `__str__` method.
///
@ -4111,11 +4312,10 @@ impl<'db> Type<'db> {
}
Self::ModuleLiteral(module) => Some(TypeDefinition::Module(module.module(db))),
Self::ClassLiteral(class_literal) => {
Some(TypeDefinition::Class(class_literal.class().definition(db)))
}
Self::Instance(instance) => {
Some(TypeDefinition::Class(instance.class().definition(db)))
Some(TypeDefinition::Class(class_literal.definition(db)))
}
Self::GenericAlias(alias) => Some(TypeDefinition::Class(alias.definition(db))),
Self::Instance(instance) => Some(TypeDefinition::Class(instance.class.definition(db))),
Self::KnownInstance(instance) => match instance {
KnownInstanceType::TypeVar(var) => {
Some(TypeDefinition::TypeVar(var.definition(db)))
@ -5133,6 +5333,11 @@ pub struct FunctionType<'db> {
/// A set of special decorators that were applied to this function
decorators: FunctionDecorators,
/// A specialization that should be applied to the function's parameter and return types,
/// either because the function is itself generic, or because it appears in the body of a
/// generic class.
specialization: Option<Specialization<'db>>,
}
#[salsa::tracked]
@ -5183,13 +5388,17 @@ impl<'db> FunctionType<'db> {
/// would depend on the function's AST and rerun for every change in that file.
#[salsa::tracked(return_ref)]
pub(crate) fn signature(self, db: &'db dyn Db) -> Signature<'db> {
let internal_signature = self.internal_signature(db);
let mut internal_signature = self.internal_signature(db);
if self.has_known_decorator(db, FunctionDecorators::OVERLOAD) {
Signature::todo("return type of overloaded function")
} else {
internal_signature
return Signature::todo("return type of overloaded function");
}
if let Some(specialization) = self.specialization(db) {
internal_signature.apply_specialization(db, specialization);
}
internal_signature
}
/// Typed internally-visible signature for this function.
@ -5212,6 +5421,21 @@ impl<'db> FunctionType<'db> {
pub(crate) fn is_known(self, db: &'db dyn Db, known_function: KnownFunction) -> bool {
self.known(db) == Some(known_function)
}
fn apply_specialization(self, db: &'db dyn Db, specialization: Specialization<'db>) -> Self {
let specialization = match self.specialization(db) {
Some(existing) => existing.apply_specialization(db, specialization),
None => specialization,
};
Self::new(
db,
self.name(db).clone(),
self.known(db),
self.body_scope(db),
self.decorators(db),
Some(specialization),
)
}
}
/// Non-exhaustive enumeration of known functions (e.g. `builtins.reveal_type`, ...) that might
@ -5382,6 +5606,12 @@ impl<'db> CallableType<'db> {
CallableType::new(db, Signature::new(parameters, return_ty))
}
fn apply_specialization(self, db: &'db dyn Db, specialization: Specialization<'db>) -> Self {
let mut signature = self.signature(db).clone();
signature.apply_specialization(db, specialization);
Self::new(db, signature)
}
/// Returns `true` if this is a fully static callable type.
///
/// A callable type is fully static if all of its parameters and return type are fully static
@ -6006,8 +6236,8 @@ impl<'db> TypeAliasType<'db> {
/// Either the explicit `metaclass=` keyword of the class, or the inferred metaclass of one of its base classes.
#[derive(Debug, Clone, PartialEq, Eq, salsa::Update)]
pub(super) struct MetaclassCandidate<'db> {
metaclass: Class<'db>,
explicit_metaclass_of: Class<'db>,
metaclass: ClassType<'db>,
explicit_metaclass_of: ClassLiteralType<'db>,
}
#[salsa::interned(debug)]
@ -6579,6 +6809,10 @@ impl<'db> TupleType<'db> {
pub fn len(&self, db: &'db dyn Db) -> usize {
self.elements(db).len()
}
pub fn iter(&self, db: &'db dyn Db) -> impl Iterator<Item = Type<'db>> + 'db + '_ {
self.elements(db).iter().copied()
}
}
// Make sure that the `Type` enum does not grow unexpectedly.

8
crates/red_knot_python_semantic/src/types/builder.rs
View File

@ -292,7 +292,7 @@ impl<'db> InnerIntersectionBuilder<'db> {
_ => {
let known_instance = new_positive
.into_instance()
.and_then(|instance| instance.class().known(db));
.and_then(|instance| instance.class.known(db));
if known_instance == Some(KnownClass::Object) {
// `object & T` -> `T`; it is always redundant to add `object` to an intersection
@ -312,7 +312,7 @@ impl<'db> InnerIntersectionBuilder<'db> {
new_positive = Type::BooleanLiteral(false);
}
Type::Instance(instance)
if instance.class().is_known(db, KnownClass::Bool) =>
if instance.class.is_known(db, KnownClass::Bool) =>
{
match new_positive {
// `bool & AlwaysTruthy` -> `Literal[True]`
@ -406,7 +406,7 @@ impl<'db> InnerIntersectionBuilder<'db> {
self.positive
.iter()
.filter_map(|ty| ty.into_instance())
.filter_map(|instance| instance.class().known(db))
.filter_map(|instance| instance.class.known(db))
.any(KnownClass::is_bool)
};
@ -422,7 +422,7 @@ impl<'db> InnerIntersectionBuilder<'db> {
Type::Never => {
// Adding ~Never to an intersection is a no-op.
}
Type::Instance(instance) if instance.class().is_object(db) => {
Type::Instance(instance) if instance.class.is_object(db) => {
// Adding ~object to an intersection results in Never.
*self = Self::default();
self.positive.insert(Type::Never);

8
crates/red_knot_python_semantic/src/types/call/bind.rs
View File

@ -18,8 +18,8 @@ use crate::types::diagnostic::{
};
use crate::types::signatures::{Parameter, ParameterForm};
use crate::types::{
todo_type, BoundMethodType, ClassLiteralType, FunctionDecorators, KnownClass, KnownFunction,
KnownInstanceType, MethodWrapperKind, PropertyInstanceType, UnionType, WrapperDescriptorKind,
todo_type, BoundMethodType, FunctionDecorators, KnownClass, KnownFunction, KnownInstanceType,
MethodWrapperKind, PropertyInstanceType, UnionType, WrapperDescriptorKind,
};
use ruff_db::diagnostic::{OldSecondaryDiagnosticMessage, Span};
use ruff_python_ast as ast;
@ -566,7 +566,7 @@ impl<'db> Bindings<'db> {
_ => {}
},
Type::ClassLiteral(ClassLiteralType { class }) => match class.known(db) {
Type::ClassLiteral(class) => match class.known(db) {
Some(KnownClass::Bool) => match overload.parameter_types() {
[Some(arg)] => overload.set_return_type(arg.bool(db).into_type(db)),
[None] => overload.set_return_type(Type::BooleanLiteral(false)),
@ -1064,7 +1064,7 @@ impl<'db> CallableDescription<'db> {
}),
Type::ClassLiteral(class_type) => Some(CallableDescription {
kind: "class",
name: class_type.class().name(db),
name: class_type.name(db),
}),
Type::BoundMethod(bound_method) => Some(CallableDescription {
kind: "bound method",

638
crates/red_knot_python_semantic/src/types/class.rs
View File

@ -6,6 +6,7 @@ use super::{
Type, TypeAliasType, TypeQualifiers, TypeVarInstance,
};
use crate::semantic_index::definition::Definition;
use crate::types::generics::{GenericContext, Specialization};
use crate::{
module_resolver::file_to_module,
semantic_index::{
@ -24,36 +25,199 @@ use crate::{
};
use indexmap::IndexSet;
use itertools::Itertools as _;
use ruff_db::files::{File, FileRange};
use ruff_db::files::File;
use ruff_python_ast::{self as ast, PythonVersion};
use rustc_hash::FxHashSet;
/// Representation of a runtime class object.
///
/// Does not in itself represent a type,
/// but is used as the inner data for several structs that *do* represent types.
#[salsa::interned(debug)]
fn explicit_bases_cycle_recover<'db>(
_db: &'db dyn Db,
_value: &[Type<'db>],
_count: u32,
_self: ClassLiteralType<'db>,
) -> salsa::CycleRecoveryAction<Box<[Type<'db>]>> {
salsa::CycleRecoveryAction::Iterate
}
fn explicit_bases_cycle_initial<'db>(
_db: &'db dyn Db,
_self: ClassLiteralType<'db>,
) -> Box<[Type<'db>]> {
Box::default()
}
fn try_mro_cycle_recover<'db>(
_db: &'db dyn Db,
_value: &Result<Mro<'db>, MroError<'db>>,
_count: u32,
_self: ClassLiteralType<'db>,
_specialization: Option<Specialization<'db>>,
) -> salsa::CycleRecoveryAction<Result<Mro<'db>, MroError<'db>>> {
salsa::CycleRecoveryAction::Iterate
}
#[allow(clippy::unnecessary_wraps)]
fn try_mro_cycle_initial<'db>(
db: &'db dyn Db,
self_: ClassLiteralType<'db>,
specialization: Option<Specialization<'db>>,
) -> Result<Mro<'db>, MroError<'db>> {
Ok(Mro::from_error(
db,
self_.apply_optional_specialization(db, specialization),
))
}
#[allow(clippy::ref_option, clippy::trivially_copy_pass_by_ref)]
fn inheritance_cycle_recover<'db>(
_db: &'db dyn Db,
_value: &Option<InheritanceCycle>,
_count: u32,
_self: ClassLiteralType<'db>,
) -> salsa::CycleRecoveryAction<Option<InheritanceCycle>> {
salsa::CycleRecoveryAction::Iterate
}
fn inheritance_cycle_initial<'db>(
_db: &'db dyn Db,
_self: ClassLiteralType<'db>,
) -> Option<InheritanceCycle> {
None
}
/// Representation of a class definition statement in the AST. This does not in itself represent a
/// type, but is used as the inner data for several structs that *do* represent types.
#[derive(Clone, Debug, Eq, Hash, PartialEq, salsa::Update)]
pub struct Class<'db> {
/// Name of the class at definition
#[return_ref]
pub(crate) name: ast::name::Name,
body_scope: ScopeId<'db>,
pub(crate) body_scope: ScopeId<'db>,
pub(crate) known: Option<KnownClass>,
}
#[salsa::tracked]
impl<'db> Class<'db> {
fn file(&self, db: &dyn Db) -> File {
self.body_scope.file(db)
}
/// Return the original [`ast::StmtClassDef`] node associated with this class
///
/// ## Note
/// Only call this function from queries in the same file or your
/// query depends on the AST of another file (bad!).
fn node(&self, db: &'db dyn Db) -> &'db ast::StmtClassDef {
self.body_scope.node(db).expect_class()
}
fn definition(&self, db: &'db dyn Db) -> Definition<'db> {
let index = semantic_index(db, self.body_scope.file(db));
index.expect_single_definition(self.body_scope.node(db).expect_class())
}
}
/// A [`Class`] that is not generic.
#[salsa::interned(debug)]
pub struct NonGenericClass<'db> {
#[return_ref]
pub(crate) class: Class<'db>,
}
impl<'db> From<NonGenericClass<'db>> for Type<'db> {
fn from(class: NonGenericClass<'db>) -> Type<'db> {
Type::ClassLiteral(ClassLiteralType::NonGeneric(class))
}
}
/// A [`Class`] that is generic.
#[salsa::interned(debug)]
pub struct GenericClass<'db> {
#[return_ref]
pub(crate) class: Class<'db>,
pub(crate) generic_context: GenericContext<'db>,
}
impl<'db> From<GenericClass<'db>> for Type<'db> {
fn from(class: GenericClass<'db>) -> Type<'db> {
Type::ClassLiteral(ClassLiteralType::Generic(class))
}
}
/// A specialization of a generic class with a particular assignment of types to typevars.
#[salsa::interned(debug)]
pub struct GenericAlias<'db> {
pub(crate) origin: GenericClass<'db>,
pub(crate) specialization: Specialization<'db>,
}
impl<'db> GenericAlias<'db> {
pub(crate) fn definition(self, db: &'db dyn Db) -> Definition<'db> {
let scope = self.body_scope(db);
let index = semantic_index(db, scope.file(db));
index.expect_single_definition(scope.node(db).expect_class())
self.origin(db).class(db).definition(db)
}
}
impl<'db> From<GenericAlias<'db>> for Type<'db> {
fn from(alias: GenericAlias<'db>) -> Type<'db> {
Type::GenericAlias(alias)
}
}
/// Represents a class type, which might be a non-generic class, or a specialization of a generic
/// class.
#[derive(
Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd, salsa::Supertype, salsa::Update,
)]
pub enum ClassType<'db> {
NonGeneric(NonGenericClass<'db>),
Generic(GenericAlias<'db>),
}
#[salsa::tracked]
impl<'db> ClassType<'db> {
fn class(self, db: &'db dyn Db) -> &'db Class<'db> {
match self {
Self::NonGeneric(non_generic) => non_generic.class(db),
Self::Generic(generic) => generic.origin(db).class(db),
}
}
/// Returns the class literal and specialization for this class. For a non-generic class, this
/// is the class itself. For a generic alias, this is the alias's origin.
pub(crate) fn class_literal(
self,
db: &'db dyn Db,
) -> (ClassLiteralType<'db>, Option<Specialization<'db>>) {
match self {
Self::NonGeneric(non_generic) => (ClassLiteralType::NonGeneric(non_generic), None),
Self::Generic(generic) => (
ClassLiteralType::Generic(generic.origin(db)),
Some(generic.specialization(db)),
),
}
}
pub(crate) fn name(self, db: &'db dyn Db) -> &'db ast::name::Name {
&self.class(db).name
}
pub(crate) fn known(self, db: &'db dyn Db) -> Option<KnownClass> {
self.class(db).known
}
pub(crate) fn definition(self, db: &'db dyn Db) -> Definition<'db> {
self.class(db).definition(db)
}
fn specialize_type(self, db: &'db dyn Db, ty: Type<'db>) -> Type<'db> {
match self {
Self::NonGeneric(_) => ty,
Self::Generic(generic) => ty.apply_specialization(db, generic.specialization(db)),
}
}
/// Return `true` if this class represents `known_class`
pub(crate) fn is_known(self, db: &'db dyn Db, known_class: KnownClass) -> bool {
self.known(db) == Some(known_class)
self.class(db).known == Some(known_class)
}
/// Return `true` if this class represents the builtin class `object`
@ -61,6 +225,202 @@ impl<'db> Class<'db> {
self.is_known(db, KnownClass::Object)
}
/// Iterate over the [method resolution order] ("MRO") of the class.
///
/// If the MRO could not be accurately resolved, this method falls back to iterating
/// over an MRO that has the class directly inheriting from `Unknown`. Use
/// [`ClassLiteralType::try_mro`] if you need to distinguish between the success and failure
/// cases rather than simply iterating over the inferred resolution order for the class.
///
/// [method resolution order]: https://docs.python.org/3/glossary.html#term-method-resolution-order
pub(super) fn iter_mro(self, db: &'db dyn Db) -> impl Iterator<Item = ClassBase<'db>> {
let (class_literal, specialization) = self.class_literal(db);
class_literal.iter_mro(db, specialization)
}
/// Is this class final?
pub(super) fn is_final(self, db: &'db dyn Db) -> bool {
let (class_literal, _) = self.class_literal(db);
class_literal.is_final(db)
}
/// Return `true` if `other` is present in this class's MRO.
pub(super) fn is_subclass_of(self, db: &'db dyn Db, other: ClassType<'db>) -> bool {
// `is_subclass_of` is checking the subtype relation, in which gradual types do not
// participate, so we should not return `True` if we find `Any/Unknown` in the MRO.
self.iter_mro(db).contains(&ClassBase::Class(other))
}
/// Return the metaclass of this class, or `type[Unknown]` if the metaclass cannot be inferred.
pub(super) fn metaclass(self, db: &'db dyn Db) -> Type<'db> {
let (class_literal, _) = self.class_literal(db);
self.specialize_type(db, class_literal.metaclass(db))
}
/// Return a type representing "the set of all instances of the metaclass of this class".
pub(super) fn metaclass_instance_type(self, db: &'db dyn Db) -> Type<'db> {
self
.metaclass(db)
.to_instance(db)
.expect("`Type::to_instance()` should always return `Some()` when called on the type of a metaclass")
}
/// Returns the class member of this class named `name`.
///
/// The member resolves to a member on the class itself or any of its proper superclasses.
///
/// TODO: Should this be made private...?
pub(super) fn class_member(
self,
db: &'db dyn Db,
name: &str,
policy: MemberLookupPolicy,
) -> SymbolAndQualifiers<'db> {
let (class_literal, specialization) = self.class_literal(db);
class_literal
.class_member(db, specialization, name, policy)
.map_type(|ty| self.specialize_type(db, ty))
}
/// Returns the inferred type of the class member named `name`. Only bound members
/// or those marked as ClassVars are considered.
///
/// Returns [`Symbol::Unbound`] if `name` cannot be found in this class's scope
/// directly. Use [`ClassType::class_member`] if you require a method that will
/// traverse through the MRO until it finds the member.
pub(super) fn own_class_member(self, db: &'db dyn Db, name: &str) -> SymbolAndQualifiers<'db> {
let (class_literal, _) = self.class_literal(db);
class_literal
.own_class_member(db, name)
.map_type(|ty| self.specialize_type(db, ty))
}
/// Returns the `name` attribute of an instance of this class.
///
/// The attribute could be defined in the class body, but it could also be an implicitly
/// defined attribute that is only present in a method (typically `__init__`).
///
/// The attribute might also be defined in a superclass of this class.
pub(super) fn instance_member(self, db: &'db dyn Db, name: &str) -> SymbolAndQualifiers<'db> {
let (class_literal, specialization) = self.class_literal(db);
class_literal
.instance_member(db, specialization, name)
.map_type(|ty| self.specialize_type(db, ty))
}
/// A helper function for `instance_member` that looks up the `name` attribute only on
/// this class, not on its superclasses.
fn own_instance_member(self, db: &'db dyn Db, name: &str) -> SymbolAndQualifiers<'db> {
let (class_literal, _) = self.class_literal(db);
class_literal
.own_instance_member(db, name)
.map_type(|ty| self.specialize_type(db, ty))
}
}
impl<'db> From<GenericAlias<'db>> for ClassType<'db> {
fn from(generic: GenericAlias<'db>) -> ClassType<'db> {
ClassType::Generic(generic)
}
}
impl<'db> From<ClassType<'db>> for Type<'db> {
fn from(class: ClassType<'db>) -> Type<'db> {
match class {
ClassType::NonGeneric(non_generic) => non_generic.into(),
ClassType::Generic(generic) => generic.into(),
}
}
}
/// Represents a single class object at runtime, which might be a non-generic class, or a generic
/// class that has not been specialized.
#[derive(
Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd, salsa::Supertype, salsa::Update,
)]
pub enum ClassLiteralType<'db> {
NonGeneric(NonGenericClass<'db>),
Generic(GenericClass<'db>),
}
#[salsa::tracked]
impl<'db> ClassLiteralType<'db> {
fn class(self, db: &'db dyn Db) -> &'db Class<'db> {
match self {
Self::NonGeneric(non_generic) => non_generic.class(db),
Self::Generic(generic) => generic.class(db),
}
}
pub(crate) fn name(self, db: &'db dyn Db) -> &'db ast::name::Name {
&self.class(db).name
}
pub(crate) fn known(self, db: &'db dyn Db) -> Option<KnownClass> {
self.class(db).known
}
/// Return `true` if this class represents `known_class`
pub(crate) fn is_known(self, db: &'db dyn Db, known_class: KnownClass) -> bool {
self.class(db).known == Some(known_class)
}
/// Return `true` if this class represents the builtin class `object`
pub(crate) fn is_object(self, db: &'db dyn Db) -> bool {
self.is_known(db, KnownClass::Object)
}
pub(crate) fn body_scope(self, db: &'db dyn Db) -> ScopeId<'db> {
self.class(db).body_scope
}
pub(crate) fn definition(self, db: &'db dyn Db) -> Definition<'db> {
self.class(db).definition(db)
}
pub(crate) fn apply_optional_specialization(
self,
db: &'db dyn Db,
specialization: Option<Specialization<'db>>,
) -> ClassType<'db> {
match (self, specialization) {
(Self::NonGeneric(non_generic), _) => ClassType::NonGeneric(non_generic),
(Self::Generic(generic), None) => {
let specialization = generic.generic_context(db).default_specialization(db);
ClassType::Generic(GenericAlias::new(db, generic, specialization))
}
(Self::Generic(generic), Some(specialization)) => {
ClassType::Generic(GenericAlias::new(db, generic, specialization))
}
}
}
/// Returns the default specialization of this class. For non-generic classes, the class is
/// returned unchanged. For a non-specialized generic class, we return a generic alias that
/// applies the default specialization to the class's typevars.
pub(crate) fn default_specialization(self, db: &'db dyn Db) -> ClassType<'db> {
match self {
Self::NonGeneric(non_generic) => ClassType::NonGeneric(non_generic),
Self::Generic(generic) => {
let specialization = generic.generic_context(db).default_specialization(db);
ClassType::Generic(GenericAlias::new(db, generic, specialization))
}
}
}
/// Returns the unknown specialization of this class. For non-generic classes, the class is
/// returned unchanged. For a non-specialized generic class, we return a generic alias that
/// maps each of the class's typevars to `Unknown`.
pub(crate) fn unknown_specialization(self, db: &'db dyn Db) -> ClassType<'db> {
match self {
Self::NonGeneric(non_generic) => ClassType::NonGeneric(non_generic),
Self::Generic(generic) => {
let specialization = generic.generic_context(db).unknown_specialization(db);
ClassType::Generic(GenericAlias::new(db, generic, specialization))
}
}
}
/// Return an iterator over the inferred types of this class's *explicit* bases.
///
/// Note that any class (except for `object`) that has no explicit
@ -79,21 +439,21 @@ impl<'db> Class<'db> {
}
/// Iterate over this class's explicit bases, filtering out any bases that are not class objects.
fn fully_static_explicit_bases(self, db: &'db dyn Db) -> impl Iterator<Item = Class<'db>> {
fn fully_static_explicit_bases(self, db: &'db dyn Db) -> impl Iterator<Item = ClassType<'db>> {
self.explicit_bases(db)
.iter()
.copied()
.filter_map(Type::into_class_literal)
.map(|ClassLiteralType { class }| class)
.filter_map(Type::into_class_type)
}
#[salsa::tracked(return_ref, cycle_fn=explicit_bases_cycle_recover, cycle_initial=explicit_bases_cycle_initial)]
fn explicit_bases_query(self, db: &'db dyn Db) -> Box<[Type<'db>]> {
tracing::trace!("Class::explicit_bases_query: {}", self.name(db));
let class = self.class(db);
tracing::trace!("ClassLiteralType::explicit_bases_query: {}", class.name);
let class_stmt = self.node(db);
let class_stmt = class.node(db);
let class_definition =
semantic_index(db, self.file(db)).expect_single_definition(class_stmt);
semantic_index(db, class.file(db)).expect_single_definition(class_stmt);
class_stmt
.bases()
@ -102,40 +462,19 @@ impl<'db> Class<'db> {
.collect()
}
fn file(self, db: &dyn Db) -> File {
self.body_scope(db).file(db)
}
/// Return the original [`ast::StmtClassDef`] node associated with this class
///
/// ## Note
/// Only call this function from queries in the same file or your
/// query depends on the AST of another file (bad!).
fn node(self, db: &'db dyn Db) -> &'db ast::StmtClassDef {
self.body_scope(db).node(db).expect_class()
}
/// Returns the file range of the class's name.
pub fn focus_range(self, db: &dyn Db) -> FileRange {
FileRange::new(self.file(db), self.node(db).name.range)
}
pub fn full_range(self, db: &dyn Db) -> FileRange {
FileRange::new(self.file(db), self.node(db).range)
}
/// Return the types of the decorators on this class
#[salsa::tracked(return_ref)]
fn decorators(self, db: &'db dyn Db) -> Box<[Type<'db>]> {
tracing::trace!("Class::decorators: {}", self.name(db));
let class = self.class(db);
tracing::trace!("ClassLiteralType::decorators: {}", class.name);
let class_stmt = self.node(db);
let class_stmt = class.node(db);
if class_stmt.decorator_list.is_empty() {
return Box::new([]);
}
let class_definition =
semantic_index(db, self.file(db)).expect_single_definition(class_stmt);
semantic_index(db, class.file(db)).expect_single_definition(class_stmt);
class_stmt
.decorator_list
@ -164,28 +503,43 @@ impl<'db> Class<'db> {
///
/// [method resolution order]: https://docs.python.org/3/glossary.html#term-method-resolution-order
#[salsa::tracked(return_ref, cycle_fn=try_mro_cycle_recover, cycle_initial=try_mro_cycle_initial)]
pub(super) fn try_mro(self, db: &'db dyn Db) -> Result<Mro<'db>, MroError<'db>> {
tracing::trace!("Class::try_mro: {}", self.name(db));
Mro::of_class(db, self)
pub(super) fn try_mro(
self,
db: &'db dyn Db,
specialization: Option<Specialization<'db>>,
) -> Result<Mro<'db>, MroError<'db>> {
let class = self.class(db);
tracing::trace!("ClassLiteralType::try_mro: {}", class.name);
Mro::of_class(db, self, specialization)
}
/// Iterate over the [method resolution order] ("MRO") of the class.
///
/// If the MRO could not be accurately resolved, this method falls back to iterating
/// over an MRO that has the class directly inheriting from `Unknown`. Use
/// [`Class::try_mro`] if you need to distinguish between the success and failure
/// [`ClassLiteralType::try_mro`] if you need to distinguish between the success and failure
/// cases rather than simply iterating over the inferred resolution order for the class.
///
/// [method resolution order]: https://docs.python.org/3/glossary.html#term-method-resolution-order
pub(super) fn iter_mro(self, db: &'db dyn Db) -> impl Iterator<Item = ClassBase<'db>> {
MroIterator::new(db, self)
pub(super) fn iter_mro(
self,
db: &'db dyn Db,
specialization: Option<Specialization<'db>>,
) -> impl Iterator<Item = ClassBase<'db>> {
MroIterator::new(db, self, specialization)
}
/// Return `true` if `other` is present in this class's MRO.
pub(super) fn is_subclass_of(self, db: &'db dyn Db, other: Class) -> bool {
pub(super) fn is_subclass_of(
self,
db: &'db dyn Db,
specialization: Option<Specialization<'db>>,
other: ClassType<'db>,
) -> bool {
// `is_subclass_of` is checking the subtype relation, in which gradual types do not
// participate, so we should not return `True` if we find `Any/Unknown` in the MRO.
self.iter_mro(db).contains(&ClassBase::Class(other))
self.iter_mro(db, specialization)
.contains(&ClassBase::Class(other))
}
/// Return the explicit `metaclass` of this class, if one is defined.
@ -194,14 +548,15 @@ impl<'db> Class<'db> {
/// Only call this function from queries in the same file or your
/// query depends on the AST of another file (bad!).
fn explicit_metaclass(self, db: &'db dyn Db) -> Option<Type<'db>> {
let class_stmt = self.node(db);
let class = self.class(db);
let class_stmt = class.node(db);
let metaclass_node = &class_stmt
.arguments
.as_ref()?
.find_keyword("metaclass")?
.value;
let class_definition = self.definition(db);
let class_definition = class.definition(db);
Some(definition_expression_type(
db,
@ -227,7 +582,8 @@ impl<'db> Class<'db> {
/// Return the metaclass of this class, or an error if the metaclass cannot be inferred.
#[salsa::tracked]
pub(super) fn try_metaclass(self, db: &'db dyn Db) -> Result<Type<'db>, MetaclassError<'db>> {
tracing::trace!("Class::try_metaclass: {}", self.name(db));
let class = self.class(db);
tracing::trace!("ClassLiteralType::try_metaclass: {}", class.name);
// Identify the class's own metaclass (or take the first base class's metaclass).
let mut base_classes = self.fully_static_explicit_bases(db).peekable();
@ -243,18 +599,19 @@ impl<'db> Class<'db> {
let (metaclass, class_metaclass_was_from) = if let Some(metaclass) = explicit_metaclass {
(metaclass, self)
} else if let Some(base_class) = base_classes.next() {
(base_class.metaclass(db), base_class)
let (base_class_literal, _) = base_class.class_literal(db);
(base_class.metaclass(db), base_class_literal)
} else {
(KnownClass::Type.to_class_literal(db), self)
};
let mut candidate = if let Type::ClassLiteral(metaclass_ty) = metaclass {
let mut candidate = if let Some(metaclass_ty) = metaclass.into_class_type() {
MetaclassCandidate {
metaclass: metaclass_ty.class,
metaclass: metaclass_ty,
explicit_metaclass_of: class_metaclass_was_from,
}
} else {
let name = Type::string_literal(db, self.name(db));
let name = Type::string_literal(db, &class.name);
let bases = TupleType::from_elements(db, self.explicit_bases(db));
// TODO: Should be `dict[str, Any]`
let namespace = KnownClass::Dict.to_instance(db);
@ -290,32 +647,34 @@ impl<'db> Class<'db> {
// - https://github.com/python/cpython/blob/83ba8c2bba834c0b92de669cac16fcda17485e0e/Objects/typeobject.c#L3629-L3663
for base_class in base_classes {
let metaclass = base_class.metaclass(db);
let Type::ClassLiteral(metaclass) = metaclass else {
let Some(metaclass) = metaclass.into_class_type() else {
continue;
};
if metaclass.class.is_subclass_of(db, candidate.metaclass) {
if metaclass.is_subclass_of(db, candidate.metaclass) {
let (base_class_literal, _) = base_class.class_literal(db);
candidate = MetaclassCandidate {
metaclass: metaclass.class,
explicit_metaclass_of: base_class,
metaclass,
explicit_metaclass_of: base_class_literal,
};
continue;
}
if candidate.metaclass.is_subclass_of(db, metaclass.class) {
if candidate.metaclass.is_subclass_of(db, metaclass) {
continue;
}
let (base_class_literal, _) = base_class.class_literal(db);
return Err(MetaclassError {
kind: MetaclassErrorKind::Conflict {
candidate1: candidate,
candidate2: MetaclassCandidate {
metaclass: metaclass.class,
explicit_metaclass_of: base_class,
metaclass,
explicit_metaclass_of: base_class_literal,
},
candidate1_is_base_class: explicit_metaclass.is_none(),
},
});
}
Ok(Type::class_literal(candidate.metaclass))
Ok(candidate.metaclass.into())
}
/// Returns the class member of this class named `name`.
@ -326,11 +685,12 @@ impl<'db> Class<'db> {
pub(super) fn class_member(
self,
db: &'db dyn Db,
specialization: Option<Specialization<'db>>,
name: &str,
policy: MemberLookupPolicy,
) -> SymbolAndQualifiers<'db> {
if name == "__mro__" {
let tuple_elements = self.iter_mro(db).map(Type::from);
let tuple_elements = self.iter_mro(db, specialization).map(Type::from);
return Symbol::bound(TupleType::from_elements(db, tuple_elements)).into();
}
@ -345,7 +705,7 @@ impl<'db> Class<'db> {
let mut lookup_result: LookupResult<'db> =
Err(LookupError::Unbound(TypeQualifiers::empty()));
for superclass in self.iter_mro(db) {
for superclass in self.iter_mro(db, specialization) {
match superclass {
ClassBase::Dynamic(DynamicType::TodoProtocol) => {
// TODO: We currently skip `Protocol` when looking up class members, in order to
@ -415,7 +775,7 @@ impl<'db> Class<'db> {
/// or those marked as ClassVars are considered.
///
/// Returns [`Symbol::Unbound`] if `name` cannot be found in this class's scope
/// directly. Use [`Class::class_member`] if you require a method that will
/// directly. Use [`ClassLiteralType::class_member`] if you require a method that will
/// traverse through the MRO until it finds the member.
pub(super) fn own_class_member(self, db: &'db dyn Db, name: &str) -> SymbolAndQualifiers<'db> {
let body_scope = self.body_scope(db);
@ -428,11 +788,16 @@ impl<'db> Class<'db> {
/// defined attribute that is only present in a method (typically `__init__`).
///
/// The attribute might also be defined in a superclass of this class.
pub(super) fn instance_member(self, db: &'db dyn Db, name: &str) -> SymbolAndQualifiers<'db> {
pub(super) fn instance_member(
self,
db: &'db dyn Db,
specialization: Option<Specialization<'db>>,
name: &str,
) -> SymbolAndQualifiers<'db> {
let mut union = UnionBuilder::new(db);
let mut union_qualifiers = TypeQualifiers::empty();
for superclass in self.iter_mro(db) {
for superclass in self.iter_mro(db, specialization) {
match superclass {
ClassBase::Dynamic(DynamicType::TodoProtocol) => {
// TODO: We currently skip `Protocol` when looking up instance members, in order to
@ -680,21 +1045,22 @@ impl<'db> Class<'db> {
/// Also, populates `visited_classes` with all base classes of `self`.
fn is_cyclically_defined_recursive<'db>(
db: &'db dyn Db,
class: Class<'db>,
classes_on_stack: &mut IndexSet<Class<'db>>,
visited_classes: &mut IndexSet<Class<'db>>,
class: ClassLiteralType<'db>,
classes_on_stack: &mut IndexSet<ClassLiteralType<'db>>,
visited_classes: &mut IndexSet<ClassLiteralType<'db>>,
) -> bool {
let mut result = false;
for explicit_base_class in class.fully_static_explicit_bases(db) {
if !classes_on_stack.insert(explicit_base_class) {
let (explicit_base_class_literal, _) = explicit_base_class.class_literal(db);
if !classes_on_stack.insert(explicit_base_class_literal) {
return true;
}
if visited_classes.insert(explicit_base_class) {
if visited_classes.insert(explicit_base_class_literal) {
// If we find a cycle, keep searching to check if we can reach the starting class.
result |= is_cyclically_defined_recursive(
db,
explicit_base_class,
explicit_base_class_literal,
classes_on_stack,
visited_classes,
);
@ -718,48 +1084,13 @@ impl<'db> Class<'db> {
}
}
fn explicit_bases_cycle_recover<'db>(
_db: &'db dyn Db,
_value: &[Type<'db>],
_count: u32,
_self: Class<'db>,
) -> salsa::CycleRecoveryAction<Box<[Type<'db>]>> {
salsa::CycleRecoveryAction::Iterate
}
fn explicit_bases_cycle_initial<'db>(_db: &'db dyn Db, _self: Class<'db>) -> Box<[Type<'db>]> {
Box::default()
}
fn try_mro_cycle_recover<'db>(
_db: &'db dyn Db,
_value: &Result<Mro<'db>, MroError<'db>>,
_count: u32,
_self: Class<'db>,
) -> salsa::CycleRecoveryAction<Result<Mro<'db>, MroError<'db>>> {
salsa::CycleRecoveryAction::Iterate
}
#[allow(clippy::unnecessary_wraps)]
fn try_mro_cycle_initial<'db>(
db: &'db dyn Db,
self_: Class<'db>,
) -> Result<Mro<'db>, MroError<'db>> {
Ok(Mro::from_error(db, self_))
}
#[allow(clippy::ref_option, clippy::trivially_copy_pass_by_ref)]
fn inheritance_cycle_recover<'db>(
_db: &'db dyn Db,
_value: &Option<InheritanceCycle>,
_count: u32,
_self: Class<'db>,
) -> salsa::CycleRecoveryAction<Option<InheritanceCycle>> {
salsa::CycleRecoveryAction::Iterate
}
fn inheritance_cycle_initial<'db>(_db: &'db dyn Db, _self: Class<'db>) -> Option<InheritanceCycle> {
None
impl<'db> From<ClassLiteralType<'db>> for Type<'db> {
fn from(class: ClassLiteralType<'db>) -> Type<'db> {
match class {
ClassLiteralType::NonGeneric(non_generic) => non_generic.into(),
ClassLiteralType::Generic(generic) => generic.into(),
}
}
}
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
@ -778,48 +1109,13 @@ impl InheritanceCycle {
}
}
/// A singleton type representing a single class object at runtime.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, salsa::Update)]
pub struct ClassLiteralType<'db> {
pub(super) class: Class<'db>,
}
impl<'db> ClassLiteralType<'db> {
pub(super) fn class(self) -> Class<'db> {
self.class
}
pub(crate) fn body_scope(self, db: &'db dyn Db) -> ScopeId<'db> {
self.class.body_scope(db)
}
pub(super) fn class_member(
self,
db: &'db dyn Db,
name: &str,
policy: MemberLookupPolicy,
) -> SymbolAndQualifiers<'db> {
self.class.class_member(db, name, policy)
}
}
impl<'db> From<ClassLiteralType<'db>> for Type<'db> {
fn from(value: ClassLiteralType<'db>) -> Self {
Self::ClassLiteral(value)
}
}
/// A type representing the set of runtime objects which are instances of a certain class.
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, salsa::Update)]
pub struct InstanceType<'db> {
pub(super) class: Class<'db>,
pub class: ClassType<'db>,
}
impl<'db> InstanceType<'db> {
pub(super) fn class(self) -> Class<'db> {
self.class
}
pub(super) fn is_subtype_of(self, db: &'db dyn Db, other: InstanceType<'db>) -> bool {
// N.B. The subclass relation is fully static
self.class.is_subclass_of(db, other.class)
@ -839,7 +1135,7 @@ impl<'db> From<InstanceType<'db>> for Type<'db> {
/// Note: good candidates are any classes in `[crate::module_resolver::module::KnownModule]`
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
#[cfg_attr(test, derive(strum_macros::EnumIter))]
pub enum KnownClass {
pub(crate) enum KnownClass {
// To figure out where an stdlib symbol is defined, you can go into `crates/red_knot_vendored`
// and grep for the symbol name in any `.pyi` file.
@ -1081,8 +1377,8 @@ impl<'db> KnownClass {
/// If the class cannot be found in typeshed, a debug-level log message will be emitted stating this.
pub(crate) fn to_instance(self, db: &'db dyn Db) -> Type<'db> {
self.to_class_literal(db)
.into_class_literal()
.map(|ClassLiteralType { class }| Type::instance(class))
.into_class_type()
.map(Type::instance)
.unwrap_or_else(Type::unknown)
}
@ -1096,9 +1392,9 @@ impl<'db> KnownClass {
) -> Result<ClassLiteralType<'db>, KnownClassLookupError<'db>> {
let symbol = known_module_symbol(db, self.canonical_module(db), self.name(db)).symbol;
match symbol {
Symbol::Type(Type::ClassLiteral(class_type), Boundness::Bound) => Ok(class_type),
Symbol::Type(Type::ClassLiteral(class_type), Boundness::PossiblyUnbound) => {
Err(KnownClassLookupError::ClassPossiblyUnbound { class_type })
Symbol::Type(Type::ClassLiteral(class_literal), Boundness::Bound) => Ok(class_literal),
Symbol::Type(Type::ClassLiteral(class_literal), Boundness::PossiblyUnbound) => {
Err(KnownClassLookupError::ClassPossiblyUnbound { class_literal })
}
Symbol::Type(found_type, _) => {
Err(KnownClassLookupError::SymbolNotAClass { found_type })
@ -1133,8 +1429,8 @@ impl<'db> KnownClass {
}
match lookup_error {
KnownClassLookupError::ClassPossiblyUnbound { class_type, .. } => {
Type::class_literal(class_type.class)
KnownClassLookupError::ClassPossiblyUnbound { class_literal, .. } => {
class_literal.into()
}
KnownClassLookupError::ClassNotFound { .. }
| KnownClassLookupError::SymbolNotAClass { .. } => Type::unknown(),
@ -1148,16 +1444,16 @@ impl<'db> KnownClass {
/// If the class cannot be found in typeshed, a debug-level log message will be emitted stating this.
pub(crate) fn to_subclass_of(self, db: &'db dyn Db) -> Type<'db> {
self.to_class_literal(db)
.into_class_literal()
.map(|ClassLiteralType { class }| SubclassOfType::from(db, class))
.into_class_type()
.map(|class| SubclassOfType::from(db, class))
.unwrap_or_else(SubclassOfType::subclass_of_unknown)
}
/// Return `true` if this symbol can be resolved to a class definition `class` in typeshed,
/// *and* `class` is a subclass of `other`.
pub(super) fn is_subclass_of(self, db: &'db dyn Db, other: Class<'db>) -> bool {
pub(super) fn is_subclass_of(self, db: &'db dyn Db, other: ClassType<'db>) -> bool {
self.try_to_class_literal(db)
.is_ok_and(|ClassLiteralType { class }| class.is_subclass_of(db, other))
.is_ok_and(|class| class.is_subclass_of(db, None, other))
}
/// Return the module in which we should look up the definition for this class
@ -1489,7 +1785,9 @@ pub(crate) enum KnownClassLookupError<'db> {
SymbolNotAClass { found_type: Type<'db> },
/// There is a symbol by that name in the expected typeshed module,
/// and it's a class definition, but it's possibly unbound.
ClassPossiblyUnbound { class_type: ClassLiteralType<'db> },
ClassPossiblyUnbound {
class_literal: ClassLiteralType<'db>,
},
}
impl<'db> KnownClassLookupError<'db> {
@ -1769,7 +2067,7 @@ impl<'db> KnownInstanceType<'db> {
}
/// Return `true` if this symbol is an instance of `class`.
pub(super) fn is_instance_of(self, db: &'db dyn Db, class: Class<'db>) -> bool {
pub(super) fn is_instance_of(self, db: &'db dyn Db, class: ClassType<'db>) -> bool {
self.class().is_subclass_of(db, class)
}

37
crates/red_knot_python_semantic/src/types/class_base.rs
View File

@ -1,16 +1,19 @@
use crate::types::{todo_type, Class, DynamicType, KnownClass, KnownInstanceType, Type};
use crate::types::{todo_type, ClassType, DynamicType, KnownClass, KnownInstanceType, Type};
use crate::Db;
use itertools::Either;
/// Enumeration of the possible kinds of types we allow in class bases.
///
/// This is much more limited than the [`Type`] enum:
/// all types that would be invalid to have as a class base are
/// transformed into [`ClassBase::unknown`]
/// This is much more limited than the [`Type`] enum: all types that would be invalid to have as a
/// class base are transformed into [`ClassBase::unknown`]
///
/// Note that a non-specialized generic class _cannot_ be a class base. When we see a
/// non-specialized generic class in any type expression (including the list of base classes), we
/// automatically construct the default specialization for that class.
#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, salsa::Update)]
pub(crate) enum ClassBase<'db> {
Dynamic(DynamicType),
Class(Class<'db>),
Class(ClassType<'db>),
}
impl<'db> ClassBase<'db> {
@ -39,7 +42,12 @@ impl<'db> ClassBase<'db> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self.base {
ClassBase::Dynamic(dynamic) => dynamic.fmt(f),
ClassBase::Class(class) => write!(f, "<class '{}'>", class.name(self.db)),
ClassBase::Class(class @ ClassType::NonGeneric(_)) => {
write!(f, "<class '{}'>", class.name(self.db))
}
ClassBase::Class(ClassType::Generic(alias)) => {
write!(f, "<class '{}'>", alias.display(self.db))
}
}
}
}
@ -51,8 +59,8 @@ impl<'db> ClassBase<'db> {
pub(super) fn object(db: &'db dyn Db) -> Self {
KnownClass::Object
.to_class_literal(db)
.into_class_literal()
.map_or(Self::unknown(), |literal| Self::Class(literal.class()))
.into_class_type()
.map_or(Self::unknown(), Self::Class)
}
/// Attempt to resolve `ty` into a `ClassBase`.
@ -61,11 +69,12 @@ impl<'db> ClassBase<'db> {
pub(super) fn try_from_type(db: &'db dyn Db, ty: Type<'db>) -> Option<Self> {
match ty {
Type::Dynamic(dynamic) => Some(Self::Dynamic(dynamic)),
Type::ClassLiteral(literal) => Some(if literal.class().is_known(db, KnownClass::Any) {
Type::ClassLiteral(literal) => Some(if literal.is_known(db, KnownClass::Any) {
Self::Dynamic(DynamicType::Any)
} else {
Self::Class(literal.class())
Self::Class(literal.default_specialization(db))
}),
Type::GenericAlias(generic) => Some(Self::Class(ClassType::Generic(generic))),
Type::Union(_) => None, // TODO -- forces consideration of multiple possible MROs?
Type::Intersection(_) => None, // TODO -- probably incorrect?
Type::Instance(_) => None, // TODO -- handle `__mro_entries__`?
@ -159,7 +168,7 @@ impl<'db> ClassBase<'db> {
}
}
pub(super) fn into_class(self) -> Option<Class<'db>> {
pub(super) fn into_class(self) -> Option<ClassType<'db>> {
match self {
Self::Class(class) => Some(class),
Self::Dynamic(_) => None,
@ -178,8 +187,8 @@ impl<'db> ClassBase<'db> {
}
}
impl<'db> From<Class<'db>> for ClassBase<'db> {
fn from(value: Class<'db>) -> Self {
impl<'db> From<ClassType<'db>> for ClassBase<'db> {
fn from(value: ClassType<'db>) -> Self {
ClassBase::Class(value)
}
}
@ -188,7 +197,7 @@ impl<'db> From<ClassBase<'db>> for Type<'db> {
fn from(value: ClassBase<'db>) -> Self {
match value {
ClassBase::Dynamic(dynamic) => Type::Dynamic(dynamic),
ClassBase::Class(class) => Type::class_literal(class),
ClassBase::Class(class) => class.into(),
}
}
}

4
crates/red_knot_python_semantic/src/types/diagnostic.rs
View File

@ -7,7 +7,7 @@ use crate::types::string_annotation::{
IMPLICIT_CONCATENATED_STRING_TYPE_ANNOTATION, INVALID_SYNTAX_IN_FORWARD_ANNOTATION,
RAW_STRING_TYPE_ANNOTATION,
};
use crate::types::{ClassLiteralType, KnownInstanceType, Type};
use crate::types::{KnownInstanceType, Type};
use ruff_db::diagnostic::{Diagnostic, OldSecondaryDiagnosticMessage, Span};
use ruff_python_ast::{self as ast, AnyNodeRef};
use ruff_text_size::Ranged;
@ -1025,7 +1025,7 @@ fn report_invalid_assignment_with_message(
message: std::fmt::Arguments,
) {
match target_ty {
Type::ClassLiteral(ClassLiteralType { class }) => {
Type::ClassLiteral(class) => {
context.report_lint(&INVALID_ASSIGNMENT, node, format_args!(
"Implicit shadowing of class `{}`; annotate to make it explicit if this is intentional",
class.name(context.db())));

148
crates/red_knot_python_semantic/src/types/display.rs
View File

@ -6,11 +6,13 @@ use ruff_db::display::FormatterJoinExtension;
use ruff_python_ast::str::{Quote, TripleQuotes};
use ruff_python_literal::escape::AsciiEscape;
use crate::types::class::{ClassType, GenericAlias, GenericClass};
use crate::types::class_base::ClassBase;
use crate::types::generics::Specialization;
use crate::types::signatures::{Parameter, Parameters, Signature};
use crate::types::{
ClassLiteralType, InstanceType, IntersectionType, KnownClass, MethodWrapperKind,
StringLiteralType, Type, UnionType, WrapperDescriptorKind,
InstanceType, IntersectionType, KnownClass, MethodWrapperKind, StringLiteralType, Type,
TypeVarInstance, UnionType, WrapperDescriptorKind,
};
use crate::Db;
use rustc_hash::FxHashMap;
@ -34,7 +36,7 @@ impl Display for DisplayType<'_> {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
let representation = self.ty.representation(self.db);
match self.ty {
Type::ClassLiteral(literal) if literal.class().is_known(self.db, KnownClass::Any) => {
Type::ClassLiteral(literal) if literal.is_known(self.db, KnownClass::Any) => {
write!(f, "typing.Any")
}
Type::IntLiteral(_)
@ -42,6 +44,7 @@ impl Display for DisplayType<'_> {
| Type::StringLiteral(_)
| Type::BytesLiteral(_)
| Type::ClassLiteral(_)
| Type::GenericAlias(_)
| Type::FunctionLiteral(_) => {
write!(f, "Literal[{representation}]")
}
@ -69,20 +72,21 @@ impl Display for DisplayRepresentation<'_> {
match self.ty {
Type::Dynamic(dynamic) => dynamic.fmt(f),
Type::Never => f.write_str("Never"),
Type::Instance(InstanceType { class }) => {
let representation = match class.known(self.db) {
Some(KnownClass::NoneType) => "None",
Some(KnownClass::NoDefaultType) => "NoDefault",
_ => class.name(self.db),
};
f.write_str(representation)
}
Type::Instance(InstanceType { class }) => match (class, class.known(self.db)) {
(_, Some(KnownClass::NoneType)) => f.write_str("None"),
(_, Some(KnownClass::NoDefaultType)) => f.write_str("NoDefault"),
(ClassType::NonGeneric(class), _) => f.write_str(&class.class(self.db).name),
(ClassType::Generic(alias), _) => write!(f, "{}", alias.display(self.db)),
},
Type::PropertyInstance(_) => f.write_str("property"),
Type::ModuleLiteral(module) => {
write!(f, "<module '{}'>", module.module(self.db).name())
}
// TODO functions and classes should display using a fully qualified name
Type::ClassLiteral(ClassLiteralType { class }) => f.write_str(class.name(self.db)),
Type::ClassLiteral(class) => f.write_str(class.name(self.db)),
Type::GenericAlias(generic) => {
write!(f, "{}", generic.display(self.db))
}
Type::SubclassOf(subclass_of_ty) => match subclass_of_ty.subclass_of() {
// Only show the bare class name here; ClassBase::display would render this as
// type[<class 'Foo'>] instead of type[Foo].
@ -90,21 +94,49 @@ impl Display for DisplayRepresentation<'_> {
ClassBase::Dynamic(dynamic) => write!(f, "type[{dynamic}]"),
},
Type::KnownInstance(known_instance) => f.write_str(known_instance.repr(self.db)),
Type::FunctionLiteral(function) => f.write_str(function.name(self.db)),
Type::FunctionLiteral(function) => {
f.write_str(function.name(self.db))?;
if let Some(specialization) = function.specialization(self.db) {
specialization.display_short(self.db).fmt(f)?;
}
Ok(())
}
Type::Callable(callable) => callable.signature(self.db).display(self.db).fmt(f),
Type::BoundMethod(bound_method) => {
let function = bound_method.function(self.db);
let self_instance = bound_method.self_instance(self.db);
let self_instance_specialization = match self_instance {
Type::Instance(InstanceType {
class: ClassType::Generic(alias),
}) => Some(alias.specialization(self.db)),
_ => None,
};
let specialization = match function.specialization(self.db) {
Some(specialization)
if self_instance_specialization.is_none_or(|sis| specialization == sis) =>
{
specialization.display_short(self.db).to_string()
}
_ => String::new(),
};
write!(
f,
"<bound method `{method}` of `{instance}`>",
method = bound_method.function(self.db).name(self.db),
instance = bound_method.self_instance(self.db).display(self.db)
"<bound method `{method}{specialization}` of `{instance}`>",
method = function.name(self.db),
instance = bound_method.self_instance(self.db).display(self.db),
)
}
Type::MethodWrapper(MethodWrapperKind::FunctionTypeDunderGet(function)) => {
write!(
f,
"<method-wrapper `__get__` of `{function}`>",
function = function.name(self.db)
"<method-wrapper `__get__` of `{function}{specialization}`>",
function = function.name(self.db),
specialization = if let Some(specialization) = function.specialization(self.db)
{
specialization.display_short(self.db).to_string()
} else {
String::new()
},
)
}
Type::MethodWrapper(MethodWrapperKind::PropertyDunderGet(_)) => {
@ -174,6 +206,86 @@ impl Display for DisplayRepresentation<'_> {
}
}
impl<'db> GenericAlias<'db> {
pub(crate) fn display(&'db self, db: &'db dyn Db) -> DisplayGenericAlias<'db> {
DisplayGenericAlias {
origin: self.origin(db),
specialization: self.specialization(db),
db,
}
}
}
pub(crate) struct DisplayGenericAlias<'db> {
origin: GenericClass<'db>,
specialization: Specialization<'db>,
db: &'db dyn Db,
}
impl Display for DisplayGenericAlias<'_> {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
write!(
f,
"{origin}{specialization}",
origin = self.origin.class(self.db).name,
specialization = self.specialization.display_short(self.db),
)
}
}
impl<'db> Specialization<'db> {
/// Renders the specialization in full, e.g. `{T = int, U = str}`.
pub fn display(&'db self, db: &'db dyn Db) -> DisplaySpecialization<'db> {
DisplaySpecialization {
typevars: self.generic_context(db).variables(db),
types: self.types(db),
db,
full: true,
}
}
/// Renders the specialization as it would appear in a subscript expression, e.g. `[int, str]`.
pub fn display_short(&'db self, db: &'db dyn Db) -> DisplaySpecialization<'db> {
DisplaySpecialization {
typevars: self.generic_context(db).variables(db),
types: self.types(db),
db,
full: false,
}
}
}
pub struct DisplaySpecialization<'db> {
typevars: &'db [TypeVarInstance<'db>],
types: &'db [Type<'db>],
db: &'db dyn Db,
full: bool,
}
impl Display for DisplaySpecialization<'_> {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
if self.full {
f.write_char('{')?;
for (idx, (var, ty)) in self.typevars.iter().zip(self.types).enumerate() {
if idx > 0 {
f.write_str(", ")?;
}
write!(f, "{} = {}", var.name(self.db), ty.display(self.db))?;
}
f.write_char('}')
} else {
f.write_char('[')?;
for (idx, (_, ty)) in self.typevars.iter().zip(self.types).enumerate() {
if idx > 0 {
f.write_str(", ")?;
}
write!(f, "{}", ty.display(self.db))?;
}
f.write_char(']')
}
}
}
impl<'db> Signature<'db> {
fn display(&'db self, db: &'db dyn Db) -> DisplaySignature<'db> {
DisplaySignature {

148
crates/red_knot_python_semantic/src/types/generics.rs Normal file
View File

@ -0,0 +1,148 @@
use ruff_python_ast as ast;
use crate::semantic_index::SemanticIndex;
use crate::types::signatures::{Parameter, Parameters, Signature};
use crate::types::{
declaration_type, KnownInstanceType, Type, TypeVarBoundOrConstraints, TypeVarInstance,
UnionType,
};
use crate::Db;
/// A list of formal type variables for a generic function, class, or type alias.
#[salsa::tracked(debug)]
pub struct GenericContext<'db> {
#[return_ref]
pub(crate) variables: Box<[TypeVarInstance<'db>]>,
}
impl<'db> GenericContext<'db> {
pub(crate) fn from_type_params(
db: &'db dyn Db,
index: &'db SemanticIndex<'db>,
type_params_node: &ast::TypeParams,
) -> Self {
let variables = type_params_node
.iter()
.filter_map(|type_param| Self::variable_from_type_param(db, index, type_param))
.collect();
Self::new(db, variables)
}
fn variable_from_type_param(
db: &'db dyn Db,
index: &'db SemanticIndex<'db>,
type_param_node: &ast::TypeParam,
) -> Option<TypeVarInstance<'db>> {
match type_param_node {
ast::TypeParam::TypeVar(node) => {
let definition = index.expect_single_definition(node);
let Type::KnownInstance(KnownInstanceType::TypeVar(typevar)) =
declaration_type(db, definition).inner_type()
else {
panic!("typevar should be inferred as a TypeVarInstance");
};
Some(typevar)
}
// TODO: Support these!
ast::TypeParam::ParamSpec(_) => None,
ast::TypeParam::TypeVarTuple(_) => None,
}
}
pub(crate) fn signature(self, db: &'db dyn Db) -> Signature<'db> {
let parameters = Parameters::new(
self.variables(db)
.iter()
.map(|typevar| Self::parameter_from_typevar(db, *typevar)),
);
Signature::new(parameters, None)
}
fn parameter_from_typevar(db: &'db dyn Db, typevar: TypeVarInstance<'db>) -> Parameter<'db> {
let mut parameter = Parameter::positional_only(Some(typevar.name(db).clone()));
match typevar.bound_or_constraints(db) {
Some(TypeVarBoundOrConstraints::UpperBound(bound)) => {
// TODO: This should be a type form.
parameter = parameter.with_annotated_type(bound);
}
Some(TypeVarBoundOrConstraints::Constraints(constraints)) => {
// TODO: This should be a new type variant where only these exact types are
// assignable, and not subclasses of them, nor a union of them.
parameter = parameter
.with_annotated_type(UnionType::from_elements(db, constraints.iter(db)));
}
None => {}
}
parameter
}
pub(crate) fn default_specialization(self, db: &'db dyn Db) -> Specialization<'db> {
let types = self
.variables(db)
.iter()
.map(|typevar| typevar.default_ty(db).unwrap_or(Type::unknown()))
.collect();
self.specialize(db, types)
}
pub(crate) fn unknown_specialization(self, db: &'db dyn Db) -> Specialization<'db> {
let types = vec![Type::unknown(); self.variables(db).len()];
self.specialize(db, types.into())
}
pub(crate) fn specialize(
self,
db: &'db dyn Db,
types: Box<[Type<'db>]>,
) -> Specialization<'db> {
Specialization::new(db, self, types)
}
}
/// An assignment of a specific type to each type variable in a generic scope.
#[salsa::tracked(debug)]
pub struct Specialization<'db> {
pub(crate) generic_context: GenericContext<'db>,
#[return_ref]
pub(crate) types: Box<[Type<'db>]>,
}
impl<'db> Specialization<'db> {
/// Applies a specialization to this specialization. This is used, for instance, when a generic
/// class inherits from a generic alias:
///
/// ```py
/// class A[T]: ...
/// class B[U](A[U]): ...
/// ```
///
/// `B` is a generic class, whose MRO includes the generic alias `A[U]`, which specializes `A`
/// with the specialization `{T: U}`. If `B` is specialized to `B[int]`, with specialization
/// `{U: int}`, we can apply the second specialization to the first, resulting in `T: int`.
/// That lets us produce the generic alias `A[int]`, which is the corresponding entry in the
/// MRO of `B[int]`.
pub(crate) fn apply_specialization(self, db: &'db dyn Db, other: Specialization<'db>) -> Self {
let types = self
.types(db)
.into_iter()
.map(|ty| ty.apply_specialization(db, other))
.collect();
Specialization::new(db, self.generic_context(db), types)
}
pub(crate) fn normalized(self, db: &'db dyn Db) -> Self {
let types = self.types(db).iter().map(|ty| ty.normalized(db)).collect();
Self::new(db, self.generic_context(db), types)
}
/// Returns the type that a typevar is specialized to, or None if the typevar isn't part of
/// this specialization.
pub(crate) fn get(self, db: &'db dyn Db, typevar: TypeVarInstance<'db>) -> Option<Type<'db>> {
self.generic_context(db)
.variables(db)
.into_iter()
.zip(self.types(db))
.find(|(var, _)| **var == typevar)
.map(|(_, ty)| *ty)
}
}

205
crates/red_knot_python_semantic/src/types/infer.rs
View File

@ -37,6 +37,7 @@ use itertools::{Either, Itertools};
use ruff_db::diagnostic::{DiagnosticId, Severity};
use ruff_db::files::File;
use ruff_db::parsed::parsed_module;
use ruff_python_ast::visitor::{walk_expr, Visitor};
use ruff_python_ast::{self as ast, AnyNodeRef, ExprContext};
use ruff_text_size::{Ranged, TextRange};
use rustc_hash::{FxHashMap, FxHashSet};
@ -61,6 +62,7 @@ use crate::symbol::{
typing_extensions_symbol, Boundness, LookupError,
};
use crate::types::call::{Argument, Bindings, CallArgumentTypes, CallArguments, CallError};
use crate::types::class::MetaclassErrorKind;
use crate::types::diagnostic::{
report_implicit_return_type, report_invalid_arguments_to_annotated,
report_invalid_arguments_to_callable, report_invalid_assignment,
@ -73,18 +75,18 @@ use crate::types::diagnostic::{
INVALID_TYPE_VARIABLE_CONSTRAINTS, POSSIBLY_UNBOUND_IMPORT, UNDEFINED_REVEAL,
UNRESOLVED_ATTRIBUTE, UNRESOLVED_IMPORT, UNSUPPORTED_OPERATOR,
};
use crate::types::generics::GenericContext;
use crate::types::mro::MroErrorKind;
use crate::types::unpacker::{UnpackResult, Unpacker};
use crate::types::{
class::MetaclassErrorKind, todo_type, Class, DynamicType, FunctionType, IntersectionBuilder,
IntersectionType, KnownClass, KnownFunction, KnownInstanceType, MetaclassCandidate, Parameter,
ParameterForm, Parameters, SliceLiteralType, SubclassOfType, Symbol, SymbolAndQualifiers,
todo_type, CallDunderError, CallableSignature, CallableType, Class, ClassLiteralType,
DynamicType, FunctionDecorators, FunctionType, GenericAlias, GenericClass, IntersectionBuilder,
IntersectionType, KnownClass, KnownFunction, KnownInstanceType, MemberLookupPolicy,
MetaclassCandidate, NonGenericClass, Parameter, ParameterForm, Parameters, Signature,
Signatures, SliceLiteralType, StringLiteralType, SubclassOfType, Symbol, SymbolAndQualifiers,
Truthiness, TupleType, Type, TypeAliasType, TypeAndQualifiers, TypeArrayDisplay,
TypeQualifiers, TypeVarBoundOrConstraints, TypeVarInstance, UnionBuilder, UnionType,
};
use crate::types::{
CallableType, FunctionDecorators, MemberLookupPolicy, Signature, StringLiteralType,
};
use crate::unpack::{Unpack, UnpackPosition};
use crate::util::subscript::{PyIndex, PySlice};
use crate::Db;
@ -102,7 +104,6 @@ use super::slots::check_class_slots;
use super::string_annotation::{
parse_string_annotation, BYTE_STRING_TYPE_ANNOTATION, FSTRING_TYPE_ANNOTATION,
};
use super::{CallDunderError, ClassLiteralType};
/// Infer all types for a [`ScopeId`], including all definitions and expressions in that scope.
/// Use when checking a scope, or needing to provide a type for an arbitrary expression in the
@ -708,7 +709,7 @@ impl<'db> TypeInferenceBuilder<'db> {
if let DefinitionKind::Class(class) = definition.kind(self.db()) {
ty.inner_type()
.into_class_literal()
.map(|ty| (ty.class(), class.node()))
.map(|ty| (ty, class.node()))
} else {
None
}
@ -736,10 +737,7 @@ impl<'db> TypeInferenceBuilder<'db> {
// (2) Check for classes that inherit from `@final` classes
for (i, base_class) in class.explicit_bases(self.db()).iter().enumerate() {
// dynamic/unknown bases are never `@final`
let Some(base_class) = base_class
.into_class_literal()
.map(super::class::ClassLiteralType::class)
else {
let Some(base_class) = base_class.into_class_literal() else {
continue;
};
if !base_class.is_final(self.db()) {
@ -757,7 +755,7 @@ impl<'db> TypeInferenceBuilder<'db> {
}
// (3) Check that the class's MRO is resolvable
match class.try_mro(self.db()).as_ref() {
match class.try_mro(self.db(), None).as_ref() {
Err(mro_error) => {
match mro_error.reason() {
MroErrorKind::DuplicateBases(duplicates) => {
@ -983,7 +981,7 @@ impl<'db> TypeInferenceBuilder<'db> {
Type::BooleanLiteral(_) | Type::IntLiteral(_) => {}
Type::Instance(instance)
if matches!(
instance.class().known(self.db()),
instance.class.known(self.db()),
Some(KnownClass::Float | KnownClass::Int | KnownClass::Bool)
) => {}
_ => return false,
@ -1415,7 +1413,7 @@ impl<'db> TypeInferenceBuilder<'db> {
continue;
}
} else if let Type::ClassLiteral(class) = decorator_ty {
if class.class.is_known(self.db(), KnownClass::Classmethod) {
if class.is_known(self.db(), KnownClass::Classmethod) {
function_decorators |= FunctionDecorators::CLASSMETHOD;
continue;
}
@ -1453,12 +1451,15 @@ impl<'db> TypeInferenceBuilder<'db> {
.node_scope(NodeWithScopeRef::Function(function))
.to_scope_id(self.db(), self.file());
let specialization = None;
let mut inferred_ty = Type::FunctionLiteral(FunctionType::new(
self.db(),
&name.id,
function_kind,
body_scope,
function_decorators,
specialization,
));
for (decorator_ty, decorator_node) in decorator_types_and_nodes.iter().rev() {
@ -1695,6 +1696,10 @@ impl<'db> TypeInferenceBuilder<'db> {
self.infer_decorator(decorator);
}
let generic_context = type_params.as_ref().map(|type_params| {
GenericContext::from_type_params(self.db(), self.index, type_params)
});
let body_scope = self
.index
.node_scope(NodeWithScopeRef::Class(class_node))
@ -1702,8 +1707,18 @@ impl<'db> TypeInferenceBuilder<'db> {
let maybe_known_class = KnownClass::try_from_file_and_name(self.db(), self.file(), name);
let class = Class::new(self.db(), &name.id, body_scope, maybe_known_class);
let class_ty = Type::class_literal(class);
let class = Class {
name: name.id.clone(),
body_scope,
known: maybe_known_class,
};
let class_literal = match generic_context {
Some(generic_context) => {
ClassLiteralType::Generic(GenericClass::new(self.db(), class, generic_context))
}
None => ClassLiteralType::NonGeneric(NonGenericClass::new(self.db(), class)),
};
let class_ty = Type::from(class_literal);
self.add_declaration_with_binding(
class_node.into(),
@ -1719,8 +1734,12 @@ impl<'db> TypeInferenceBuilder<'db> {
}
// Inference of bases deferred in stubs
// TODO also defer stringified generic type parameters
if self.are_all_types_deferred() {
// TODO: Only defer the references that are actually string literals, instead of
// deferring the entire class definition if a string literal occurs anywhere in the
// base class list.
if self.are_all_types_deferred()
|| class_node.bases().iter().any(contains_string_literal)
{
self.types.deferred.insert(definition);
} else {
for base in class_node.bases() {
@ -2532,7 +2551,7 @@ impl<'db> TypeInferenceBuilder<'db> {
}
}
Type::ClassLiteral(..) | Type::SubclassOf(..) => {
Type::ClassLiteral(..) | Type::GenericAlias(..) | Type::SubclassOf(..) => {
match object_ty.class_member(db, attribute.into()) {
SymbolAndQualifiers {
symbol: Symbol::Type(meta_attr_ty, meta_attr_boundness),
@ -2856,10 +2875,7 @@ impl<'db> TypeInferenceBuilder<'db> {
// Handle various singletons.
if let Type::Instance(instance) = declared_ty.inner_type() {
if instance
.class()
.is_known(self.db(), KnownClass::SpecialForm)
{
if instance.class.is_known(self.db(), KnownClass::SpecialForm) {
if let Some(name_expr) = target.as_name_expr() {
if let Some(known_instance) = KnownInstanceType::try_from_file_and_name(
self.db(),
@ -4018,9 +4034,12 @@ impl<'db> TypeInferenceBuilder<'db> {
let class = match callable_type {
Type::SubclassOf(subclass_of_type) => match subclass_of_type.subclass_of() {
ClassBase::Dynamic(_) => None,
ClassBase::Class(class) => Some(class),
ClassBase::Class(class) => {
let (class_literal, _) = class.class_literal(self.db());
Some(class_literal)
}
},
Type::ClassLiteral(ClassLiteralType { class }) => Some(class),
Type::ClassLiteral(class) => Some(class),
_ => None,
};
@ -4475,7 +4494,7 @@ impl<'db> TypeInferenceBuilder<'db> {
LookupError::Unbound(_) => {
let bound_on_instance = match value_type {
Type::ClassLiteral(class) => {
!class.class().instance_member(db, attr).symbol.is_unbound()
!class.instance_member(db, None, attr).symbol.is_unbound()
}
Type::SubclassOf(subclass_of @ SubclassOfType { .. }) => {
match subclass_of.subclass_of() {
@ -4588,6 +4607,7 @@ impl<'db> TypeInferenceBuilder<'db> {
| Type::BoundMethod(_)
| Type::ModuleLiteral(_)
| Type::ClassLiteral(_)
| Type::GenericAlias(_)
| Type::SubclassOf(_)
| Type::Instance(_)
| Type::KnownInstance(_)
@ -4864,6 +4884,7 @@ impl<'db> TypeInferenceBuilder<'db> {
| Type::MethodWrapper(_)
| Type::ModuleLiteral(_)
| Type::ClassLiteral(_)
| Type::GenericAlias(_)
| Type::SubclassOf(_)
| Type::Instance(_)
| Type::KnownInstance(_)
@ -4885,6 +4906,7 @@ impl<'db> TypeInferenceBuilder<'db> {
| Type::MethodWrapper(_)
| Type::ModuleLiteral(_)
| Type::ClassLiteral(_)
| Type::GenericAlias(_)
| Type::SubclassOf(_)
| Type::Instance(_)
| Type::KnownInstance(_)
@ -5452,9 +5474,7 @@ impl<'db> TypeInferenceBuilder<'db> {
range,
),
(Type::Tuple(_), Type::Instance(instance))
if instance
.class()
.is_known(self.db(), KnownClass::VersionInfo) =>
if instance.class.is_known(self.db(), KnownClass::VersionInfo) =>
{
self.infer_binary_type_comparison(
left,
@ -5464,9 +5484,7 @@ impl<'db> TypeInferenceBuilder<'db> {
)
}
(Type::Instance(instance), Type::Tuple(_))
if instance
.class()
.is_known(self.db(), KnownClass::VersionInfo) =>
if instance.class.is_known(self.db(), KnownClass::VersionInfo) =>
{
self.infer_binary_type_comparison(
Type::version_info_tuple(self.db()),
@ -5774,11 +5792,71 @@ impl<'db> TypeInferenceBuilder<'db> {
ctx: _,
} = subscript;
// HACK ALERT: If we are subscripting a generic class, short-circuit the rest of the
// subscript inference logic and treat this as an explicit specialization.
// TODO: Move this logic into a custom callable, and update `find_name_in_mro` to return
// this callable as the `__class_getitem__` method on `type`. That probably requires
// updating all of the subscript logic below to use custom callables for all of the _other_
// special cases, too.
let value_ty = self.infer_expression(value);
if let Type::ClassLiteral(ClassLiteralType::Generic(generic_class)) = value_ty {
return self.infer_explicit_class_specialization(
subscript,
value_ty,
generic_class,
slice,
);
}
let slice_ty = self.infer_expression(slice);
self.infer_subscript_expression_types(value, value_ty, slice_ty)
}
fn infer_explicit_class_specialization(
&mut self,
subscript: &ast::ExprSubscript,
value_ty: Type<'db>,
generic_class: GenericClass<'db>,
slice_node: &ast::Expr,
) -> Type<'db> {
let mut call_argument_types = match slice_node {
ast::Expr::Tuple(tuple) => CallArgumentTypes::positional(
tuple.elts.iter().map(|elt| self.infer_type_expression(elt)),
),
_ => CallArgumentTypes::positional([self.infer_type_expression(slice_node)]),
};
let generic_context = generic_class.generic_context(self.db());
let signatures = Signatures::single(CallableSignature::single(
value_ty,
generic_context.signature(self.db()),
));
let bindings = match Bindings::match_parameters(signatures, &mut call_argument_types)
.check_types(self.db(), &mut call_argument_types)
{
Ok(bindings) => bindings,
Err(CallError(_, bindings)) => {
bindings.report_diagnostics(&self.context, subscript.into());
return Type::unknown();
}
};
let callable = bindings
.into_iter()
.next()
.expect("valid bindings should have one callable");
let (_, overload) = callable
.matching_overload()
.expect("valid bindings should have matching overload");
let specialization = generic_context.specialize(
self.db(),
overload
.parameter_types()
.iter()
.map(|ty| ty.unwrap_or(Type::unknown()))
.collect(),
);
Type::from(GenericAlias::new(self.db(), generic_class, specialization))
}
fn infer_subscript_expression_types(
&mut self,
value_node: &ast::Expr,
@ -5789,16 +5867,12 @@ impl<'db> TypeInferenceBuilder<'db> {
(
Type::Instance(instance),
Type::IntLiteral(_) | Type::BooleanLiteral(_) | Type::SliceLiteral(_),
) if instance
.class()
.is_known(self.db(), KnownClass::VersionInfo) =>
{
self.infer_subscript_expression_types(
) if instance.class.is_known(self.db(), KnownClass::VersionInfo) => self
.infer_subscript_expression_types(
value_node,
Type::version_info_tuple(self.db()),
slice_ty,
)
}
),
// Ex) Given `("a", "b", "c", "d")[1]`, return `"b"`
(Type::Tuple(tuple_ty), Type::IntLiteral(int)) if i32::try_from(int).is_ok() => {
@ -6006,9 +6080,16 @@ impl<'db> TypeInferenceBuilder<'db> {
}
}
if matches!(value_ty, Type::ClassLiteral(class_literal) if class_literal.class().is_known(self.db(), KnownClass::Type))
{
return KnownClass::GenericAlias.to_instance(self.db());
if let Type::ClassLiteral(class) = value_ty {
if class.is_known(self.db(), KnownClass::Type) {
return KnownClass::GenericAlias.to_instance(self.db());
}
if let ClassLiteralType::Generic(_) = class {
// TODO: specialize the generic class using these explicit type
// variable assignments
return value_ty;
}
}
report_non_subscriptable(
@ -6031,6 +6112,10 @@ impl<'db> TypeInferenceBuilder<'db> {
// TODO: proper support for generic classes
// For now, just infer `Sequence`, if we see something like `Sequence[str]`. This allows us
// to look up attributes on generic base classes, even if we don't understand generics yet.
// Note that this isn't handled by the clause up above for generic classes
// that use legacy type variables and an explicit `Generic` base class.
// Once we handle legacy typevars, this special case will be removed in
// favor of the specialization logic above.
value_ty
}
_ => Type::unknown(),
@ -6063,7 +6148,7 @@ impl<'db> TypeInferenceBuilder<'db> {
},
Some(Type::BooleanLiteral(b)) => SliceArg::Arg(Some(i32::from(b))),
Some(Type::Instance(instance))
if instance.class().is_known(self.db(), KnownClass::NoneType) =>
if instance.class.is_known(self.db(), KnownClass::NoneType) =>
{
SliceArg::Arg(None)
}
@ -6629,8 +6714,7 @@ impl<'db> TypeInferenceBuilder<'db> {
value_ty: Type<'db>,
) -> Type<'db> {
match value_ty {
Type::ClassLiteral(class_literal_ty) => match class_literal_ty.class().known(self.db())
{
Type::ClassLiteral(class_literal) => match class_literal.known(self.db()) {
Some(KnownClass::Tuple) => self.infer_tuple_type_expression(slice),
Some(KnownClass::Type) => self.infer_subclass_of_type_expression(slice),
_ => self.infer_subscript_type_expression(subscript, value_ty),
@ -6732,14 +6816,14 @@ impl<'db> TypeInferenceBuilder<'db> {
ast::Expr::Name(_) | ast::Expr::Attribute(_) => {
let name_ty = self.infer_expression(slice);
match name_ty {
Type::ClassLiteral(class_literal_ty) => {
if class_literal_ty
.class()
.is_known(self.db(), KnownClass::Any)
{
Type::ClassLiteral(class_literal) => {
if class_literal.is_known(self.db(), KnownClass::Any) {
SubclassOfType::subclass_of_any()
} else {
SubclassOfType::from(self.db(), class_literal_ty.class())
SubclassOfType::from(
self.db(),
class_literal.default_specialization(self.db()),
)
}
}
Type::KnownInstance(KnownInstanceType::Any) => {
@ -6820,7 +6904,7 @@ impl<'db> TypeInferenceBuilder<'db> {
} = subscript;
match value_ty {
Type::ClassLiteral(literal) if literal.class().is_known(self.db(), KnownClass::Any) => {
Type::ClassLiteral(literal) if literal.is_known(self.db(), KnownClass::Any) => {
self.context.report_lint(
&INVALID_TYPE_FORM,
subscript,
@ -7516,6 +7600,21 @@ impl StringPartsCollector {
}
}
fn contains_string_literal(expr: &ast::Expr) -> bool {
struct ContainsStringLiteral(bool);
impl<'a> Visitor<'a> for ContainsStringLiteral {
fn visit_expr(&mut self, expr: &'a ast::Expr) {
self.0 |= matches!(expr, ast::Expr::StringLiteral(_));
walk_expr(self, expr);
}
}
let mut visitor = ContainsStringLiteral(false);
visitor.visit_expr(expr);
visitor.0
}
#[cfg(test)]
mod tests {
use crate::db::tests::{setup_db, TestDb};

120
crates/red_knot_python_semantic/src/types/mro.rs
View File

@ -4,34 +4,58 @@ use std::ops::Deref;
use rustc_hash::FxHashSet;
use crate::types::class_base::ClassBase;
use crate::types::{Class, Type};
use crate::types::generics::Specialization;
use crate::types::{ClassLiteralType, ClassType, Type};
use crate::Db;
/// The inferred method resolution order of a given class.
///
/// See [`Class::iter_mro`] for more details.
/// An MRO cannot contain non-specialized generic classes. (This is why [`ClassBase`] contains a
/// [`ClassType`], not a [`ClassLiteralType`].) Any generic classes in a base class list are always
/// specialized — either because the class is explicitly specialized if there is a subscript
/// expression, or because we create the default specialization if there isn't.
///
/// The MRO of a non-specialized generic class can contain generic classes that are specialized
/// with a typevar from the inheriting class. When the inheriting class is specialized, the MRO of
/// the resulting generic alias will substitute those type variables accordingly. For instance, in
/// the following example, the MRO of `D[int]` includes `C[int]`, and the MRO of `D[U]` includes
/// `C[U]` (which is a generic alias, not a non-specialized generic class):
///
/// ```py
/// class C[T]: ...
/// class D[U](C[U]): ...
/// ```
///
/// See [`ClassType::iter_mro`] for more details.
#[derive(PartialEq, Eq, Clone, Debug, salsa::Update)]
pub(super) struct Mro<'db>(Box<[ClassBase<'db>]>);
impl<'db> Mro<'db> {
/// Attempt to resolve the MRO of a given class
/// Attempt to resolve the MRO of a given class. Because we derive the MRO from the list of
/// base classes in the class definition, this operation is performed on a [class
/// literal][ClassLiteralType], not a [class type][ClassType]. (You can _also_ get the MRO of a
/// class type, but this is done by first getting the MRO of the underlying class literal, and
/// specializing each base class as needed if the class type is a generic alias.)
///
/// In the event that a possible list of bases would (or could) lead to a
/// `TypeError` being raised at runtime due to an unresolvable MRO, we infer
/// the MRO of the class as being `[<the class in question>, Unknown, object]`.
/// This seems most likely to reduce the possibility of cascading errors
/// elsewhere.
/// In the event that a possible list of bases would (or could) lead to a `TypeError` being
/// raised at runtime due to an unresolvable MRO, we infer the MRO of the class as being `[<the
/// class in question>, Unknown, object]`. This seems most likely to reduce the possibility of
/// cascading errors elsewhere. (For a generic class, the first entry in this fallback MRO uses
/// the default specialization of the class's type variables.)
///
/// (We emit a diagnostic warning about the runtime `TypeError` in
/// [`super::infer::TypeInferenceBuilder::infer_region_scope`].)
pub(super) fn of_class(db: &'db dyn Db, class: Class<'db>) -> Result<Self, MroError<'db>> {
Self::of_class_impl(db, class).map_err(|error_kind| MroError {
kind: error_kind,
fallback_mro: Self::from_error(db, class),
pub(super) fn of_class(
db: &'db dyn Db,
class: ClassLiteralType<'db>,
specialization: Option<Specialization<'db>>,
) -> Result<Self, MroError<'db>> {
Self::of_class_impl(db, class, specialization).map_err(|err| {
err.into_mro_error(db, class.apply_optional_specialization(db, specialization))
})
}
pub(super) fn from_error(db: &'db dyn Db, class: Class<'db>) -> Self {
pub(super) fn from_error(db: &'db dyn Db, class: ClassType<'db>) -> Self {
Self::from([
ClassBase::Class(class),
ClassBase::unknown(),
@ -39,20 +63,30 @@ impl<'db> Mro<'db> {
])
}
fn of_class_impl(db: &'db dyn Db, class: Class<'db>) -> Result<Self, MroErrorKind<'db>> {
fn of_class_impl(
db: &'db dyn Db,
class: ClassLiteralType<'db>,
specialization: Option<Specialization<'db>>,
) -> Result<Self, MroErrorKind<'db>> {
let class_bases = class.explicit_bases(db);
if !class_bases.is_empty() && class.inheritance_cycle(db).is_some() {
// We emit errors for cyclically defined classes elsewhere.
// It's important that we don't even try to infer the MRO for a cyclically defined class,
// or we'll end up in an infinite loop.
return Ok(Mro::from_error(db, class));
return Ok(Mro::from_error(
db,
class.apply_optional_specialization(db, specialization),
));
}
match class_bases {
// `builtins.object` is the special case:
// the only class in Python that has an MRO with length <2
[] if class.is_object(db) => Ok(Self::from([ClassBase::Class(class)])),
[] if class.is_object(db) => Ok(Self::from([
// object is not generic, so the default specialization should be a no-op
ClassBase::Class(class.apply_optional_specialization(db, specialization)),
])),
// All other classes in Python have an MRO with length >=2.
// Even if a class has no explicit base classes,
@ -67,7 +101,10 @@ impl<'db> Mro<'db> {
// >>> Foo.__mro__
// (<class '__main__.Foo'>, <class 'object'>)
// ```
[] => Ok(Self::from([ClassBase::Class(class), ClassBase::object(db)])),
[] => Ok(Self::from([
ClassBase::Class(class.apply_optional_specialization(db, specialization)),
ClassBase::object(db),
])),
// Fast path for a class that has only a single explicit base.
//
@ -77,9 +114,11 @@ impl<'db> Mro<'db> {
[single_base] => ClassBase::try_from_type(db, *single_base).map_or_else(
|| Err(MroErrorKind::InvalidBases(Box::from([(0, *single_base)]))),
|single_base| {
Ok(std::iter::once(ClassBase::Class(class))
.chain(single_base.mro(db))
.collect())
Ok(std::iter::once(ClassBase::Class(
class.apply_optional_specialization(db, specialization),
))
.chain(single_base.mro(db))
.collect())
},
),
@ -103,7 +142,9 @@ impl<'db> Mro<'db> {
return Err(MroErrorKind::InvalidBases(invalid_bases.into_boxed_slice()));
}
let mut seqs = vec![VecDeque::from([ClassBase::Class(class)])];
let mut seqs = vec![VecDeque::from([ClassBase::Class(
class.apply_optional_specialization(db, specialization),
)])];
for base in &valid_bases {
seqs.push(base.mro(db).collect());
}
@ -118,7 +159,8 @@ impl<'db> Mro<'db> {
.filter_map(|(index, base)| Some((index, base.into_class()?)))
{
if !seen_bases.insert(base) {
duplicate_bases.push((index, base));
let (base_class_literal, _) = base.class_literal(db);
duplicate_bases.push((index, base_class_literal));
}
}
@ -178,12 +220,15 @@ impl<'db> FromIterator<ClassBase<'db>> for Mro<'db> {
///
/// Even for first-party code, where we will have to resolve the MRO for every class we encounter,
/// loading the cached MRO comes with a certain amount of overhead, so it's best to avoid calling the
/// Salsa-tracked [`Class::try_mro`] method unless it's absolutely necessary.
/// Salsa-tracked [`ClassLiteralType::try_mro`] method unless it's absolutely necessary.
pub(super) struct MroIterator<'db> {
db: &'db dyn Db,
/// The class whose MRO we're iterating over
class: Class<'db>,
class: ClassLiteralType<'db>,
/// The specialization to apply to each MRO element, if any
specialization: Option<Specialization<'db>>,
/// Whether or not we've already yielded the first element of the MRO
first_element_yielded: bool,
@ -197,10 +242,15 @@ pub(super) struct MroIterator<'db> {
}
impl<'db> MroIterator<'db> {
pub(super) fn new(db: &'db dyn Db, class: Class<'db>) -> Self {
pub(super) fn new(
db: &'db dyn Db,
class: ClassLiteralType<'db>,
specialization: Option<Specialization<'db>>,
) -> Self {
Self {
db,
class,
specialization,
first_element_yielded: false,
subsequent_elements: None,
}
@ -211,7 +261,7 @@ impl<'db> MroIterator<'db> {
fn full_mro_except_first_element(&mut self) -> impl Iterator<Item = ClassBase<'db>> + '_ {
self.subsequent_elements
.get_or_insert_with(|| {
let mut full_mro_iter = match self.class.try_mro(self.db) {
let mut full_mro_iter = match self.class.try_mro(self.db, self.specialization) {
Ok(mro) => mro.iter(),
Err(error) => error.fallback_mro().iter(),
};
@ -228,7 +278,10 @@ impl<'db> Iterator for MroIterator<'db> {
fn next(&mut self) -> Option<Self::Item> {
if !self.first_element_yielded {
self.first_element_yielded = true;
return Some(ClassBase::Class(self.class));
return Some(ClassBase::Class(
self.class
.apply_optional_specialization(self.db, self.specialization),
));
}
self.full_mro_except_first_element().next()
}
@ -273,11 +326,11 @@ pub(super) enum MroErrorKind<'db> {
/// The class has one or more duplicate bases.
///
/// This variant records the indices and [`Class`]es
/// This variant records the indices and [`ClassLiteralType`]s
/// of the duplicate bases. The indices are the indices of nodes
/// in the bases list of the class's [`StmtClassDef`](ruff_python_ast::StmtClassDef) node.
/// Each index is the index of a node representing a duplicate base.
DuplicateBases(Box<[(usize, Class<'db>)]>),
DuplicateBases(Box<[(usize, ClassLiteralType<'db>)]>),
/// The MRO is otherwise unresolvable through the C3-merge algorithm.
///
@ -285,6 +338,15 @@ pub(super) enum MroErrorKind<'db> {
UnresolvableMro { bases_list: Box<[ClassBase<'db>]> },
}
impl<'db> MroErrorKind<'db> {
pub(super) fn into_mro_error(self, db: &'db dyn Db, class: ClassType<'db>) -> MroError<'db> {
MroError {
kind: self,
fallback_mro: Mro::from_error(db, class),
}
}
}
/// Implementation of the [C3-merge algorithm] for calculating a Python class's
/// [method resolution order].
///

23
crates/red_knot_python_semantic/src/types/narrow.rs
View File

@ -159,10 +159,10 @@ impl KnownConstraintFunction {
Type::ClassLiteral(class_literal) => {
// At runtime (on Python 3.11+), this will return `True` for classes that actually
// do inherit `typing.Any` and `False` otherwise. We could accurately model that?
if class_literal.class().is_known(db, KnownClass::Any) {
if class_literal.is_known(db, KnownClass::Any) {
None
} else {
Some(constraint_fn(class_literal.class()))
Some(constraint_fn(class_literal.default_specialization(db)))
}
}
Type::SubclassOf(subclass_of_ty) => {
@ -473,8 +473,14 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
range: _,
},
}) if keywords.is_empty() => {
let Type::ClassLiteral(ClassLiteralType { class: rhs_class }) = rhs_ty else {
continue;
let rhs_class = match rhs_ty {
Type::ClassLiteral(class) => class,
Type::GenericAlias(alias) => {
ClassLiteralType::Generic(alias.origin(self.db))
}
_ => {
continue;
}
};
let [ast::Expr::Name(ast::ExprName { id, .. })] = &**args else {
@ -496,10 +502,13 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
if callable_type
.into_class_literal()
.is_some_and(|c| c.class().is_known(self.db, KnownClass::Type))
.is_some_and(|c| c.is_known(self.db, KnownClass::Type))
{
let symbol = self.expect_expr_name_symbol(id);
constraints.insert(symbol, Type::instance(rhs_class));
constraints.insert(
symbol,
Type::instance(rhs_class.unknown_specialization(self.db)),
);
}
}
_ => {}
@ -550,7 +559,7 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
Type::ClassLiteral(class_type)
if expr_call.arguments.args.len() == 1
&& expr_call.arguments.keywords.is_empty()
&& class_type.class().is_known(self.db, KnownClass::Bool) =>
&& class_type.is_known(self.db, KnownClass::Bool) =>
{
self.evaluate_expression_node_predicate(
&expr_call.arguments.args[0],

6
crates/red_knot_python_semantic/src/types/property_tests/type_generation.rs
View File

@ -11,6 +11,8 @@ use ruff_python_ast::name::Name;
/// A test representation of a type that can be transformed unambiguously into a real Type,
/// given a db.
///
/// TODO: We should add some variants that exercise generic classes and specializations thereof.
#[derive(Debug, Clone, PartialEq)]
pub(crate) enum Ty {
Never,
@ -167,7 +169,7 @@ impl Ty {
.symbol
.expect_type()
.expect_class_literal()
.class,
.default_specialization(db),
),
Ty::SubclassOfAbcClass(s) => SubclassOfType::from(
db,
@ -175,7 +177,7 @@ impl Ty {
.symbol
.expect_type()
.expect_class_literal()
.class,
.default_specialization(db),
),
Ty::AlwaysTruthy => Type::AlwaysTruthy,
Ty::AlwaysFalsy => Type::AlwaysFalsy,

38
crates/red_knot_python_semantic/src/types/signatures.rs
View File

@ -14,6 +14,7 @@ use smallvec::{smallvec, SmallVec};
use super::{definition_expression_type, DynamicType, Type};
use crate::semantic_index::definition::Definition;
use crate::types::generics::Specialization;
use crate::types::todo_type;
use crate::Db;
use ruff_python_ast::{self as ast, name::Name};
@ -261,6 +262,17 @@ impl<'db> Signature<'db> {
}
}
pub(crate) fn apply_specialization(
&mut self,
db: &'db dyn Db,
specialization: Specialization<'db>,
) {
self.parameters.apply_specialization(db, specialization);
self.return_ty = self
.return_ty
.map(|ty| ty.apply_specialization(db, specialization));
}
/// Return the parameters in this signature.
pub(crate) fn parameters(&self) -> &Parameters<'db> {
&self.parameters
@ -445,6 +457,12 @@ impl<'db> Parameters<'db> {
)
}
fn apply_specialization(&mut self, db: &'db dyn Db, specialization: Specialization<'db>) {
self.value
.iter_mut()
.for_each(|param| param.apply_specialization(db, specialization));
}
pub(crate) fn len(&self) -> usize {
self.value.len()
}
@ -606,6 +624,13 @@ impl<'db> Parameter<'db> {
self
}
fn apply_specialization(&mut self, db: &'db dyn Db, specialization: Specialization<'db>) {
self.annotated_type = self
.annotated_type
.map(|ty| ty.apply_specialization(db, specialization));
self.kind.apply_specialization(db, specialization);
}
/// Strip information from the parameter so that two equivalent parameters compare equal.
/// Normalize nested unions and intersections in the annotated type, if any.
///
@ -792,6 +817,19 @@ pub(crate) enum ParameterKind<'db> {
},
}
impl<'db> ParameterKind<'db> {
fn apply_specialization(&mut self, db: &'db dyn Db, specialization: Specialization<'db>) {
match self {
Self::PositionalOnly { default_type, .. }
| Self::PositionalOrKeyword { default_type, .. }
| Self::KeywordOnly { default_type, .. } => {
*default_type = default_type.map(|ty| ty.apply_specialization(db, specialization));
}
Self::Variadic { .. } | Self::KeywordVariadic { .. } => {}
}
}
}
/// Whether a parameter is used as a value or a type form.
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
pub(crate) enum ParameterForm {

17
crates/red_knot_python_semantic/src/types/slots.rs
View File

@ -4,7 +4,7 @@ use crate::db::Db;
use crate::symbol::{Boundness, Symbol};
use crate::types::class_base::ClassBase;
use crate::types::diagnostic::report_base_with_incompatible_slots;
use crate::types::{Class, ClassLiteralType, Type};
use crate::types::{ClassLiteralType, Type};
use super::InferContext;
@ -23,7 +23,7 @@ enum SlotsKind {
}
impl SlotsKind {
fn from(db: &dyn Db, base: Class) -> Self {
fn from(db: &dyn Db, base: ClassLiteralType) -> Self {
let Symbol::Type(slots_ty, bound) = base.own_class_member(db, "__slots__").symbol else {
return Self::NotSpecified;
};
@ -50,7 +50,11 @@ impl SlotsKind {
}
}
pub(super) fn check_class_slots(context: &InferContext, class: Class, node: &ast::StmtClassDef) {
pub(super) fn check_class_slots(
context: &InferContext,
class: ClassLiteralType,
node: &ast::StmtClassDef,
) {
let db = context.db();
let mut first_with_solid_base = None;
@ -58,16 +62,17 @@ pub(super) fn check_class_slots(context: &InferContext, class: Class, node: &ast
let mut found_second = false;
for (index, base) in class.explicit_bases(db).iter().enumerate() {
let Type::ClassLiteral(ClassLiteralType { class: base }) = base else {
let Type::ClassLiteral(base) = base else {
continue;
};
let solid_base = base.iter_mro(db).find_map(|current| {
let solid_base = base.iter_mro(db, None).find_map(|current| {
let ClassBase::Class(current) = current else {
return None;
};
match SlotsKind::from(db, current) {
let (class_literal, _) = current.class_literal(db);
match SlotsKind::from(db, class_literal) {
SlotsKind::NotEmpty => Some(current),
SlotsKind::NotSpecified | SlotsKind::Empty => None,
SlotsKind::Dynamic => None,

4
crates/red_knot_python_semantic/src/types/subclass_of.rs
View File

@ -1,6 +1,6 @@
use crate::symbol::SymbolAndQualifiers;
use super::{ClassBase, ClassLiteralType, Db, KnownClass, MemberLookupPolicy, Type};
use super::{ClassBase, Db, KnownClass, MemberLookupPolicy, Type};
/// A type that represents `type[C]`, i.e. the class object `C` and class objects that are subclasses of `C`.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, salsa::Update)]
@ -27,7 +27,7 @@ impl<'db> SubclassOfType<'db> {
ClassBase::Dynamic(_) => Type::SubclassOf(Self { subclass_of }),
ClassBase::Class(class) => {
if class.is_final(db) {
Type::ClassLiteral(ClassLiteralType { class })
Type::from(class)
} else if class.is_object(db) {
KnownClass::Type.to_instance(db)
} else {

14
crates/red_knot_python_semantic/src/types/type_ordering.rs
View File

@ -2,10 +2,7 @@ use std::cmp::Ordering;
use crate::db::Db;
use super::{
class_base::ClassBase, ClassLiteralType, DynamicType, InstanceType, KnownInstanceType,
TodoType, Type,
};
use super::{class_base::ClassBase, DynamicType, InstanceType, KnownInstanceType, TodoType, Type};
/// Return an [`Ordering`] that describes the canonical order in which two types should appear
/// in an [`crate::types::IntersectionType`] or a [`crate::types::UnionType`] in order for them
@ -93,13 +90,14 @@ pub(super) fn union_or_intersection_elements_ordering<'db>(
(Type::ModuleLiteral(_), _) => Ordering::Less,
(_, Type::ModuleLiteral(_)) => Ordering::Greater,
(
Type::ClassLiteral(ClassLiteralType { class: left }),
Type::ClassLiteral(ClassLiteralType { class: right }),
) => left.cmp(right),
(Type::ClassLiteral(left), Type::ClassLiteral(right)) => left.cmp(right),
(Type::ClassLiteral(_), _) => Ordering::Less,
(_, Type::ClassLiteral(_)) => Ordering::Greater,
(Type::GenericAlias(left), Type::GenericAlias(right)) => left.cmp(right),
(Type::GenericAlias(_), _) => Ordering::Less,
(_, Type::GenericAlias(_)) => Ordering::Greater,
(Type::SubclassOf(left), Type::SubclassOf(right)) => {
match (left.subclass_of(), right.subclass_of()) {
(ClassBase::Class(left), ClassBase::Class(right)) => left.cmp(&right),