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Ibraheem Ahmed 2025-12-16 23:42:55 +03:00 committed by GitHub
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10 changed files with 355 additions and 113 deletions

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@ -402,40 +402,48 @@ python-version = "3.12"
`generic_list.py`:
```py
from typing import Literal
from typing import Literal, Sequence
def f[T](x: T) -> list[T]:
return [x]
a = f("a")
reveal_type(a) # revealed: list[str]
x1 = f("a")
reveal_type(x1) # revealed: list[str]
b: list[int | Literal["a"]] = f("a")
reveal_type(b) # revealed: list[int | Literal["a"]]
x2: list[int | Literal["a"]] = f("a")
reveal_type(x2) # revealed: list[int | Literal["a"]]
c: list[int | str] = f("a")
reveal_type(c) # revealed: list[int | str]
x3: list[int | str] = f("a")
reveal_type(x3) # revealed: list[int | str]
d: list[int | tuple[int, int]] = f((1, 2))
reveal_type(d) # revealed: list[int | tuple[int, int]]
x4: list[int | tuple[int, int]] = f((1, 2))
reveal_type(x4) # revealed: list[int | tuple[int, int]]
e: list[int] = f(True)
reveal_type(e) # revealed: list[int]
x5: list[int] = f(True)
reveal_type(x5) # revealed: list[int]
# error: [invalid-assignment] "Object of type `list[int | str]` is not assignable to `list[int]`"
g: list[int] = f("a")
x6: list[int] = f("a")
# error: [invalid-assignment] "Object of type `list[str]` is not assignable to `tuple[int]`"
h: tuple[int] = f("a")
x7: tuple[int] = f("a")
def f2[T: int](x: T) -> T:
return x
i: int = f2(True)
reveal_type(i) # revealed: Literal[True]
x8: int = f2(True)
reveal_type(x8) # revealed: Literal[True]
j: int | str = f2(True)
reveal_type(j) # revealed: Literal[True]
x9: int | str = f2(True)
reveal_type(x9) # revealed: Literal[True]
# TODO: We could choose a concrete type here.
x10: list[int | str] | list[int | None] = [1, 2, 3]
reveal_type(x10) # revealed: list[Unknown | int]
# TODO: And here similarly.
x11: Sequence[int | str] | Sequence[int | None] = [1, 2, 3]
reveal_type(x11) # revealed: list[Unknown | int]
```
A function's arguments are also inferred using the type context:
@ -600,6 +608,48 @@ reveal_type(x7) # revealed: Contravariant[Any]
reveal_type(x8) # revealed: Invariant[Any]
```
## Declared type preference sees through subtyping
```toml
[environment]
python-version = "3.12"
```
```py
from typing import Any, Iterable, Literal, MutableSequence, Sequence
x1: Sequence[Any] = [1, 2, 3]
reveal_type(x1) # revealed: list[Any]
x2: MutableSequence[Any] = [1, 2, 3]
reveal_type(x2) # revealed: list[Any]
x3: Iterable[Any] = [1, 2, 3]
reveal_type(x3) # revealed: list[Any]
class X[T]:
value: T
def __init__(self, value: T): ...
class A[T](X[T]): ...
def a[T](value: T) -> A[T]:
return A(value)
x4: A[object] = A(1)
reveal_type(x4) # revealed: A[object]
x5: X[object] = A(1)
reveal_type(x5) # revealed: A[object]
x6: X[object] | None = A(1)
reveal_type(x6) # revealed: A[object]
x7: X[object] | None = a(1)
reveal_type(x7) # revealed: A[object]
```
## Narrow generic unions
```toml

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@ -341,3 +341,58 @@ reveal_type(x21) # revealed: X[Literal[1]]
x22: X[Literal[1]] | None = x(1)
reveal_type(x22) # revealed: X[Literal[1]]
```
## Literal annotations see through subtyping
```py
from typing import Any, Iterable, Literal, MutableSequence, Sequence
x1: Sequence[Literal[1, 2, 3]] = [1, 2, 3]
reveal_type(x1) # revealed: list[Literal[1, 2, 3]]
x2: MutableSequence[Literal[1, 2, 3]] = [1, 2, 3]
reveal_type(x2) # revealed: list[Literal[1, 2, 3]]
x3: Iterable[Literal[1, 2, 3]] = [1, 2, 3]
reveal_type(x3) # revealed: list[Literal[1, 2, 3]]
class Sup1[T]:
value: T
class Sub1[T](Sup1[T]): ...
def sub1[T](value: T) -> Sub1[T]:
return Sub1()
x4: Sub1[Literal[1]] = sub1(1)
reveal_type(x4) # revealed: Sub1[Literal[1]]
x5: Sup1[Literal[1]] = sub1(1)
reveal_type(x5) # revealed: Sub1[Literal[1]]
x6: Sup1[Literal[1]] | None = sub1(1)
reveal_type(x6) # revealed: Sub1[Literal[1]]
x7: Sup1[Literal[1]] | None = sub1(1)
reveal_type(x7) # revealed: Sub1[Literal[1]]
class Sup2A[T, U]:
value: tuple[T, U]
class Sup2B[T, U]:
value: tuple[T, U]
class Sub2[T, U](Sup2A[T, Any], Sup2B[Any, U]): ...
def sub2[T, U](x: T, y: U) -> Sub2[T, U]:
return Sub2()
x8 = sub2(1, 2)
reveal_type(x8) # revealed: Sub2[int, int]
x9: Sup2A[Literal[1], Literal[2]] = sub2(1, 2)
reveal_type(x9) # revealed: Sub2[Literal[1], int]
x10: Sup2B[Literal[1], Literal[2]] = sub2(1, 2)
reveal_type(x10) # revealed: Sub2[int, Literal[2]]
```

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@ -57,6 +57,9 @@ reveal_type(tuple((1, 2))) # revealed: tuple[Literal[1], Literal[2]]
reveal_type(tuple([1])) # revealed: tuple[Unknown | int, ...]
x1: tuple[int, ...] = tuple([1])
reveal_type(x1) # revealed: tuple[int, ...]
# error: [invalid-argument-type]
reveal_type(tuple[int]([1])) # revealed: tuple[int]

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@ -61,8 +61,8 @@ use crate::types::function::{
};
pub(crate) use crate::types::generics::GenericContext;
use crate::types::generics::{
InferableTypeVars, PartialSpecialization, Specialization, bind_typevar, typing_self,
walk_generic_context,
InferableTypeVars, PartialSpecialization, Specialization, SpecializationBuilder, bind_typevar,
typing_self, walk_generic_context,
};
use crate::types::mro::{Mro, MroError, MroIterator};
pub(crate) use crate::types::narrow::infer_narrowing_constraint;
@ -1100,7 +1100,10 @@ impl<'db> Type<'db> {
}
/// If this type is a class instance, returns its specialization.
pub(crate) fn class_specialization(self, db: &'db dyn Db) -> Option<Specialization<'db>> {
pub(crate) fn class_specialization(
self,
db: &'db dyn Db,
) -> Option<(ClassLiteral<'db>, Specialization<'db>)> {
self.specialization_of_optional(db, None)
}
@ -1111,15 +1114,17 @@ impl<'db> Type<'db> {
expected_class: ClassLiteral<'_>,
) -> Option<Specialization<'db>> {
self.specialization_of_optional(db, Some(expected_class))
.map(|(_, specialization)| specialization)
}
fn specialization_of_optional(
self,
db: &'db dyn Db,
expected_class: Option<ClassLiteral<'_>>,
) -> Option<Specialization<'db>> {
) -> Option<(ClassLiteral<'db>, Specialization<'db>)> {
let class_type = match self {
Type::NominalInstance(instance) => instance,
Type::ProtocolInstance(instance) => instance.to_nominal_instance()?,
Type::TypeAlias(alias) => alias.value_type(db).as_nominal_instance()?,
_ => return None,
}
@ -1130,7 +1135,7 @@ impl<'db> Type<'db> {
return None;
}
specialization
Some((class_literal, specialization?))
}
/// Returns the top materialization (or upper bound materialization) of this type, which is the
@ -4052,69 +4057,110 @@ impl<'db> Type<'db> {
where
F: FnMut(BoundTypeVarInstance<'db>, Type<'db>, TypeVarVariance, TypeContext<'db>),
{
self.visit_specialization_impl(
let try_visit = &mut |type_var, ty, variance, tcx| -> Result<(), ()> {
f(type_var, ty, variance, tcx);
Ok(())
};
let _ = self.try_visit_specialization(db, tcx, try_visit);
}
pub(crate) fn try_visit_specialization<F, E>(
self,
db: &'db dyn Db,
tcx: TypeContext<'db>,
mut f: F,
) -> Result<(), E>
where
F: FnMut(
BoundTypeVarInstance<'db>,
Type<'db>,
TypeVarVariance,
TypeContext<'db>,
) -> Result<(), E>,
{
self.try_visit_specialization_impl(
db,
tcx,
TypeVarVariance::Covariant,
&mut f,
&SpecializationVisitor::default(),
);
)
}
fn visit_specialization_impl(
fn try_visit_specialization_impl<E>(
self,
db: &'db dyn Db,
tcx: TypeContext<'db>,
polarity: TypeVarVariance,
f: &mut dyn FnMut(BoundTypeVarInstance<'db>, Type<'db>, TypeVarVariance, TypeContext<'db>),
f: &mut dyn FnMut(
BoundTypeVarInstance<'db>,
Type<'db>,
TypeVarVariance,
TypeContext<'db>,
) -> Result<(), E>,
visitor: &SpecializationVisitor<'db>,
) {
let Type::NominalInstance(instance) = self else {
match self {
) -> Result<(), E> {
let instance = match self {
Type::Union(union) => {
for element in union.elements(db) {
element.visit_specialization_impl(db, tcx, polarity, f, visitor);
element.try_visit_specialization_impl(db, tcx, polarity, f, visitor)?;
}
return Ok(());
}
Type::Intersection(intersection) => {
for element in intersection.positive(db) {
element.visit_specialization_impl(db, tcx, polarity, f, visitor);
element.try_visit_specialization_impl(db, tcx, polarity, f, visitor)?;
}
return Ok(());
}
Type::TypeAlias(alias) => visitor.visit(self, || {
Type::TypeAlias(alias) => {
visitor.try_visit(self, || {
alias
.value_type(db)
.visit_specialization_impl(db, tcx, polarity, f, visitor);
}),
_ => {}
}
.try_visit_specialization_impl(db, tcx, polarity, f, visitor)
})?;
return;
return Ok(());
}
Type::NominalInstance(instance) => instance,
Type::ProtocolInstance(protocol) => match protocol.to_nominal_instance() {
Some(instance) => instance,
None => return Ok(()),
},
_ => return Ok(()),
};
let (class_literal, Some(specialization)) = instance.class(db).class_literal(db) else {
return;
return Ok(());
};
let generic_context = specialization.generic_context(db);
// Collect the type mappings used to narrow the type context.
let tcx_mappings = {
let mut builder =
SpecializationBuilder::new(db, generic_context.inferable_typevars(db));
if let Some(tcx) = tcx.annotation {
let alias_instance = Type::instance(db, class_literal.identity_specialization(db));
let _ = builder.infer_reverse(tcx, alias_instance);
}
builder.into_type_mappings()
};
let tcx_specialization = tcx.annotation.and_then(|tcx| {
tcx.filter_union(db, |ty| ty.specialization_of(db, class_literal).is_some())
.specialization_of(db, class_literal)
});
for (type_var, ty) in generic_context.variables(db).zip(specialization.types(db)) {
let variance = type_var.variance_with_polarity(db, polarity);
let narrowed_tcx = TypeContext::new(tcx_mappings.get(&type_var.identity(db)).copied());
for (typevar, ty) in specialization
.generic_context(db)
.variables(db)
.zip(specialization.types(db))
{
let variance = typevar.variance_with_polarity(db, polarity);
let tcx = TypeContext::new(tcx_specialization.and_then(|spec| spec.get(db, typevar)));
f(type_var, *ty, variance, narrowed_tcx)?;
f(typevar, *ty, variance, tcx);
visitor.visit(*ty, || {
ty.visit_specialization_impl(db, tcx, variance, f, visitor);
});
visitor.try_visit(*ty, || {
ty.try_visit_specialization_impl(db, narrowed_tcx, variance, f, visitor)
})?;
}
Ok(())
}
/// Return true if there is just a single inhabitant for this type.
@ -6313,30 +6359,35 @@ impl<'db> Type<'db> {
}
Some(KnownClass::Tuple) => {
let object = Type::object();
let element_ty =
BoundTypeVarInstance::synthetic(db, "T", TypeVarVariance::Covariant);
// ```py
// class tuple:
// class tuple(Sequence[_T_co]):
// @overload
// def __new__(cls) -> tuple[()]: ...
// @overload
// def __new__(cls, iterable: Iterable[object]) -> tuple[object, ...]: ...
// def __new__(cls, iterable: Iterable[_T_co]) -> tuple[_T_co, ...]: ...
// ```
CallableBinding::from_overloads(
self,
[
Signature::new(Parameters::empty(), Some(Type::empty_tuple(db))),
Signature::new(
Signature::new_generic(
Some(GenericContext::from_typevar_instances(db, [element_ty])),
Parameters::new(
db,
[Parameter::positional_only(Some(Name::new_static(
"iterable",
)))
.with_annotated_type(
KnownClass::Iterable.to_specialized_instance(db, [object]),
KnownClass::Iterable.to_specialized_instance(
db,
[Type::TypeVar(element_ty)],
),
)],
),
Some(Type::homogeneous_tuple(db, object)),
Some(Type::homogeneous_tuple(db, Type::TypeVar(element_ty))),
),
],
)
@ -7825,6 +7876,7 @@ impl<'db> Type<'db> {
}
TypeMapping::Specialization(_) |
TypeMapping::PartialSpecialization(_) |
TypeMapping::IdentitySpecialization |
TypeMapping::PromoteLiterals(_) |
TypeMapping::BindSelf { .. } |
TypeMapping::ReplaceSelf { .. } |
@ -8001,6 +8053,7 @@ impl<'db> Type<'db> {
| Type::EnumLiteral(_) => match type_mapping {
TypeMapping::Specialization(_) |
TypeMapping::PartialSpecialization(_) |
TypeMapping::IdentitySpecialization |
TypeMapping::BindLegacyTypevars(_) |
TypeMapping::BindSelf { .. } |
TypeMapping::ReplaceSelf { .. } |
@ -8014,6 +8067,7 @@ impl<'db> Type<'db> {
Type::Dynamic(_) => match type_mapping {
TypeMapping::Specialization(_) |
TypeMapping::PartialSpecialization(_) |
TypeMapping::IdentitySpecialization |
TypeMapping::BindLegacyTypevars(_) |
TypeMapping::BindSelf { .. } |
TypeMapping::ReplaceSelf { .. } |
@ -8725,6 +8779,8 @@ pub enum TypeMapping<'a, 'db> {
Specialization(Specialization<'db>),
/// Applies a partial specialization to the type
PartialSpecialization(PartialSpecialization<'a, 'db>),
/// Resets any specializations to their identity.
IdentitySpecialization,
/// Replaces any literal types with their corresponding promoted type form (e.g. `Literal["string"]`
/// to `str`, or `def _() -> int` to `Callable[[], int]`).
PromoteLiterals(PromoteLiteralsMode),
@ -8758,6 +8814,7 @@ impl<'db> TypeMapping<'_, 'db> {
match self {
TypeMapping::Specialization(_)
| TypeMapping::PartialSpecialization(_)
| TypeMapping::IdentitySpecialization
| TypeMapping::PromoteLiterals(_)
| TypeMapping::BindLegacyTypevars(_)
| TypeMapping::Materialize(_)
@ -8792,6 +8849,7 @@ impl<'db> TypeMapping<'_, 'db> {
TypeMapping::PromoteLiterals(mode) => TypeMapping::PromoteLiterals(mode.flip()),
TypeMapping::Specialization(_)
| TypeMapping::PartialSpecialization(_)
| TypeMapping::IdentitySpecialization
| TypeMapping::BindLegacyTypevars(_)
| TypeMapping::BindSelf { .. }
| TypeMapping::ReplaceSelf { .. }
@ -10381,6 +10439,7 @@ impl<'db> BoundTypeVarInstance<'db> {
})
.unwrap_or(Type::TypeVar(self))
}
TypeMapping::IdentitySpecialization => Type::TypeVar(self),
TypeMapping::PartialSpecialization(partial) => {
let typevar = if self.is_paramspec(db) {
self.without_paramspec_attr(db)

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@ -321,7 +321,7 @@ impl<'db> BoundSuperType<'db> {
Type::NominalInstance(instance) => SuperOwnerKind::Instance(instance),
Type::ProtocolInstance(protocol) => {
if let Some(nominal_instance) = protocol.as_nominal_type() {
if let Some(nominal_instance) = protocol.to_nominal_instance() {
SuperOwnerKind::Instance(nominal_instance)
} else {
return Err(BoundSuperError::AbstractOwnerType {

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@ -3004,7 +3004,7 @@ impl<'a, 'db> ArgumentTypeChecker<'a, 'db> {
tcx.filter_union(self.db, |ty| ty.class_specialization(self.db).is_some())
.class_specialization(self.db)?;
builder.infer(return_ty, tcx).ok()?;
builder.infer_reverse(tcx, return_ty).ok()?;
Some(builder.type_mappings().clone())
});

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@ -122,14 +122,14 @@ impl<Tag, T: Hash + Eq + Clone, R: Clone> CycleDetector<Tag, T, R> {
ret
}
pub fn try_visit(&self, item: T, func: impl FnOnce() -> Option<R>) -> Option<R> {
pub fn try_visit<E>(&self, item: T, func: impl FnOnce() -> Result<R, E>) -> Result<R, E> {
if let Some(val) = self.cache.borrow().get(&item) {
return Some(val.clone());
return Ok(val.clone());
}
// We hit a cycle
if !self.seen.borrow_mut().insert(item.clone()) {
return Some(self.fallback.clone());
return Ok(self.fallback.clone());
}
// Check depth limit to prevent stack overflow from recursive generic protocols
@ -137,7 +137,7 @@ impl<Tag, T: Hash + Eq + Clone, R: Clone> CycleDetector<Tag, T, R> {
let current_depth = self.depth.get();
if current_depth >= MAX_RECURSION_DEPTH {
self.seen.borrow_mut().pop();
return Some(self.fallback.clone());
return Ok(self.fallback.clone());
}
self.depth.set(current_depth + 1);
@ -147,7 +147,7 @@ impl<Tag, T: Hash + Eq + Clone, R: Clone> CycleDetector<Tag, T, R> {
self.seen.borrow_mut().pop();
self.cache.borrow_mut().insert(item, ret.clone());
Some(ret)
Ok(ret)
}
}

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@ -1046,6 +1046,10 @@ impl<'db> Specialization<'db> {
return self.materialize_impl(db, *materialization_kind, visitor);
}
if *type_mapping == TypeMapping::IdentitySpecialization {
return self.generic_context(db).identity_specialization(db);
}
let types: Box<[_]> = self
.types(db)
.iter()
@ -1505,6 +1509,11 @@ impl<'db> SpecializationBuilder<'db> {
&self.types
}
/// Returns the current set of type mappings for this specialization.
pub(crate) fn into_type_mappings(self) -> FxHashMap<BoundTypeVarIdentity<'db>, Type<'db>> {
self.types
}
/// Map the types that have been assigned in this specialization.
pub(crate) fn mapped(
&self,
@ -1964,12 +1973,61 @@ impl<'db> SpecializationBuilder<'db> {
}
}
(_, Type::TypeAlias(alias)) => {
return self.infer_map_impl(formal, alias.value_type(self.db), polarity, f);
}
// TODO: Add more forms that we can structurally induct into: type[C], callables
_ => {}
}
Ok(())
}
/// Infer type mappings for the specialization in the reverse direction, i.e., where the given type, not the
/// declared type, contains inferable type variables.
pub(crate) fn infer_reverse(
&mut self,
formal: Type<'db>,
actual: Type<'db>,
) -> Result<(), SpecializationError<'db>> {
let identity_formal = formal.apply_type_mapping(
self.db,
&TypeMapping::IdentitySpecialization,
TypeContext::default(),
);
// Collect any type variables on the formal type.
let mut formal_type_vars = Vec::new();
formal.visit_specialization(self.db, TypeContext::default(), |typevar, _, _, _| {
formal_type_vars.push(typevar);
});
let inferable_type_vars = GenericContext::from_typevar_instances(self.db, formal_type_vars)
.inferable_typevars(self.db);
// Perform type inference in the forward direction with the inferable identity types,
// collecting the forward type mappings.
let forward_type_mappings = {
let mut builder = SpecializationBuilder::new(self.db, inferable_type_vars);
builder.infer(identity_formal, actual)?;
builder.type_mappings().clone()
};
// If there are no forward type mappings, try the other direction.
if forward_type_mappings.is_empty() {
return self.infer(actual, formal);
}
formal.try_visit_specialization(self.db, TypeContext::default(), |type_var, ty, _, _| {
// Reverse the type mappings and specialize them to their assigned types.
if let Some(formal) = forward_type_mappings.get(&type_var.identity(self.db)) {
self.infer(*formal, ty)?;
}
Ok(())
})
}
}
#[derive(Clone, Debug, Eq, PartialEq)]

View File

@ -7808,16 +7808,23 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
{
// Extract the type variable `T` from `list[T]` in typeshed.
let elt_tys = |collection_class: KnownClass| {
let class_literal = collection_class.try_to_class_literal(self.db())?;
let generic_context = class_literal.generic_context(self.db())?;
let collection_alias = collection_class
.try_to_class_literal(self.db())?
.identity_specialization(self.db())
.into_generic_alias()?;
let generic_context = collection_alias
.specialization(self.db())
.generic_context(self.db());
Some((
class_literal,
collection_alias,
generic_context,
generic_context.variables(self.db()),
))
};
let Some((class_literal, generic_context, elt_tys)) = elt_tys(collection_class) else {
let Some((collection_alias, generic_context, elt_tys)) = elt_tys(collection_class) else {
// Infer the element types without type context, and fallback to unknown for
// custom typesheds.
for elt in elts.flatten().flatten() {
@ -7838,40 +7845,46 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
annotation.filter_disjoint_elements(self.db(), collection_ty, inferable)
});
// Extract the annotated type of `T`, if provided.
let annotated_elt_tys = tcx
.known_specialization(self.db(), collection_class)
.map(|specialization| specialization.types(self.db()));
// Collect type constraints from the declared element types.
let elt_tcx_constraints = {
let mut builder = SpecializationBuilder::new(
self.db(),
generic_context.inferable_typevars(self.db()),
);
if let Some(tcx) = tcx.annotation
// If there are multiple potential type contexts, we fallback to `Unknown`.
// TODO: We could perform multi-inference here.
&& tcx
.filter_union(self.db(), |ty| ty.class_specialization(self.db()).is_some())
.class_specialization(self.db())
.is_some()
{
let collection_instance =
Type::instance(self.db(), ClassType::Generic(collection_alias));
builder.infer_reverse(tcx, collection_instance).ok()?;
}
builder.into_type_mappings()
};
// Create a set of constraints to infer a precise type for `T`.
let mut builder = SpecializationBuilder::new(self.db(), inferable);
match annotated_elt_tys {
for elt_ty in elt_tys.clone() {
let elt_tcx = elt_tcx_constraints
// The annotated type acts as a constraint for `T`.
//
// Note that we infer the annotated type _before_ the elements, to more closely match the
// order of any unions as written in the type annotation.
Some(annotated_elt_tys) => {
for (elt_ty, annotated_elt_ty) in iter::zip(elt_tys.clone(), annotated_elt_tys) {
builder
.infer(Type::TypeVar(elt_ty), *annotated_elt_ty)
.ok()?;
}
}
.get(&elt_ty.identity(self.db()))
.copied()
// If a valid type annotation was not provided, avoid restricting the type of the collection
// by unioning the inferred type with `Unknown`.
None => {
for elt_ty in elt_tys.clone() {
builder.infer(Type::TypeVar(elt_ty), Type::unknown()).ok()?;
}
}
}
.unwrap_or(Type::unknown());
let elt_tcxs = match annotated_elt_tys {
None => Either::Left(iter::repeat(TypeContext::default())),
Some(tys) => Either::Right(tys.iter().map(|ty| TypeContext::new(Some(*ty)))),
};
builder.infer(Type::TypeVar(elt_ty), elt_tcx).ok()?;
}
for elts in elts {
// An unpacking expression for a dictionary.
@ -7895,10 +7908,14 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
}
// The inferred type of each element acts as an additional constraint on `T`.
for (elt, elt_ty, elt_tcx) in itertools::izip!(elts, elt_tys.clone(), elt_tcxs.clone())
{
for (elt, elt_ty) in iter::zip(elts, elt_tys.clone()) {
let Some(elt) = elt else { continue };
let elt_tcx = TypeContext::new(
elt_tcx_constraints
.get(&elt_ty.identity(self.db()))
.copied(),
);
let inferred_elt_ty = infer_elt_expression(self, elt, elt_tcx);
// Simplify the inference based on the declared type of the element.
@ -7916,8 +7933,9 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
}
}
let class_type =
class_literal.apply_specialization(self.db(), |_| builder.build(generic_context));
let class_type = collection_alias
.origin(self.db())
.apply_specialization(self.db(), |_| builder.build(generic_context));
Type::from(class_type).to_instance(self.db())
}
@ -8398,7 +8416,6 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
call_expression: &ast::ExprCall,
tcx: TypeContext<'db>,
) -> Type<'db> {
// TODO: Use the type context for more precise inference.
let callable_type =
self.infer_maybe_standalone_expression(&call_expression.func, TypeContext::default());

View File

@ -165,7 +165,7 @@ impl<'db> Type<'db> {
// This matches the behaviour of other type checkers, and is required for us to
// recognise `str` as a subtype of `Container[str]`.
structurally_satisfied.or(db, || {
let Some(nominal_instance) = protocol.as_nominal_type() else {
let Some(nominal_instance) = protocol.to_nominal_instance() else {
return ConstraintSet::from(false);
};
@ -175,7 +175,7 @@ impl<'db> Type<'db> {
// `Q`'s members in a Liskov-incompatible way.
let type_to_test = self
.as_protocol_instance()
.and_then(ProtocolInstanceType::as_nominal_type)
.and_then(ProtocolInstanceType::to_nominal_instance)
.map(Type::NominalInstance)
.unwrap_or(self);
@ -658,7 +658,7 @@ impl<'db> ProtocolInstanceType<'db> {
/// If this is a synthesized protocol that does not correspond to a class definition
/// in source code, return `None`. These are "pure" abstract types, that cannot be
/// treated in a nominal way.
pub(super) fn as_nominal_type(self) -> Option<NominalInstanceType<'db>> {
pub(super) fn to_nominal_instance(self) -> Option<NominalInstanceType<'db>> {
match self.inner {
Protocol::FromClass(class) => {
Some(NominalInstanceType(NominalInstanceInner::NonTuple(*class)))