2197 lines
94 KiB
Rust
2197 lines
94 KiB
Rust
//! Methods for lowering the HIR to types. There are two main cases here:
|
|
//!
|
|
//! - Lowering a type reference like `&usize` or `Option<foo::bar::Baz>` to a
|
|
//! type: The entry point for this is `TyLoweringContext::lower_ty`.
|
|
//! - Building the type for an item: This happens through the `ty` query.
|
|
//!
|
|
//! This usually involves resolving names, collecting generic arguments etc.
|
|
use std::{
|
|
cell::{Cell, RefCell, RefMut},
|
|
iter,
|
|
};
|
|
|
|
use base_db::{
|
|
salsa::{impl_intern_value_trivial, Cycle},
|
|
CrateId,
|
|
};
|
|
use chalk_ir::{
|
|
cast::Cast, fold::Shift, fold::TypeFoldable, interner::HasInterner, Mutability, Safety,
|
|
};
|
|
|
|
use either::Either;
|
|
use hir_def::{
|
|
builtin_type::BuiltinType,
|
|
data::adt::StructKind,
|
|
expander::Expander,
|
|
generics::{
|
|
TypeOrConstParamData, TypeParamProvenance, WherePredicate, WherePredicateTypeTarget,
|
|
},
|
|
lang_item::LangItem,
|
|
nameres::MacroSubNs,
|
|
path::{GenericArg, GenericArgs, ModPath, Path, PathKind, PathSegment, PathSegments},
|
|
resolver::{HasResolver, Resolver, TypeNs},
|
|
type_ref::{ConstRef, TraitBoundModifier, TraitRef as HirTraitRef, TypeBound, TypeRef},
|
|
AdtId, AssocItemId, ConstId, ConstParamId, DefWithBodyId, EnumId, EnumVariantId, FunctionId,
|
|
GenericDefId, HasModule, ImplId, InTypeConstLoc, ItemContainerId, LocalFieldId, Lookup,
|
|
ModuleDefId, StaticId, StructId, TraitId, TypeAliasId, TypeOrConstParamId, TypeOwnerId,
|
|
TypeParamId, UnionId, VariantId,
|
|
};
|
|
use hir_expand::{name::Name, ExpandResult};
|
|
use intern::Interned;
|
|
use la_arena::{Arena, ArenaMap};
|
|
use rustc_hash::FxHashSet;
|
|
use smallvec::SmallVec;
|
|
use stdx::{impl_from, never};
|
|
use syntax::ast;
|
|
use triomphe::Arc;
|
|
|
|
use crate::{
|
|
all_super_traits,
|
|
consteval::{
|
|
intern_const_ref, intern_const_scalar, path_to_const, unknown_const,
|
|
unknown_const_as_generic,
|
|
},
|
|
db::HirDatabase,
|
|
make_binders,
|
|
mapping::{from_chalk_trait_id, ToChalk},
|
|
static_lifetime, to_assoc_type_id, to_chalk_trait_id, to_placeholder_idx,
|
|
utils::Generics,
|
|
utils::{
|
|
all_super_trait_refs, associated_type_by_name_including_super_traits, generics,
|
|
InTypeConstIdMetadata,
|
|
},
|
|
AliasEq, AliasTy, Binders, BoundVar, CallableSig, Const, ConstScalar, DebruijnIndex, DynTy,
|
|
FnAbi, FnPointer, FnSig, FnSubst, ImplTraitId, Interner, ParamKind, PolyFnSig, ProjectionTy,
|
|
QuantifiedWhereClause, QuantifiedWhereClauses, ReturnTypeImplTrait, ReturnTypeImplTraits,
|
|
Substitution, TraitEnvironment, TraitRef, TraitRefExt, Ty, TyBuilder, TyKind, WhereClause,
|
|
};
|
|
|
|
#[derive(Debug)]
|
|
enum ImplTraitLoweringState {
|
|
/// When turning `impl Trait` into opaque types, we have to collect the
|
|
/// bounds at the same time to get the IDs correct (without becoming too
|
|
/// complicated). I don't like using interior mutability (as for the
|
|
/// counter), but I've tried and failed to make the lifetimes work for
|
|
/// passing around a `&mut TyLoweringContext`. The core problem is that
|
|
/// we're grouping the mutable data (the counter and this field) together
|
|
/// with the immutable context (the references to the DB and resolver).
|
|
/// Splitting this up would be a possible fix.
|
|
Opaque(RefCell<Arena<ReturnTypeImplTrait>>),
|
|
Param(Cell<u16>),
|
|
Variable(Cell<u16>),
|
|
Disallowed,
|
|
}
|
|
impl ImplTraitLoweringState {
|
|
fn new(impl_trait_mode: ImplTraitLoweringMode) -> ImplTraitLoweringState {
|
|
match impl_trait_mode {
|
|
ImplTraitLoweringMode::Opaque => Self::Opaque(RefCell::new(Arena::new())),
|
|
ImplTraitLoweringMode::Param => Self::Param(Cell::new(0)),
|
|
ImplTraitLoweringMode::Variable => Self::Variable(Cell::new(0)),
|
|
ImplTraitLoweringMode::Disallowed => Self::Disallowed,
|
|
}
|
|
}
|
|
|
|
fn take(&self) -> Self {
|
|
match self {
|
|
Self::Opaque(x) => Self::Opaque(RefCell::new(x.take())),
|
|
Self::Param(x) => Self::Param(Cell::new(x.get())),
|
|
Self::Variable(x) => Self::Variable(Cell::new(x.get())),
|
|
Self::Disallowed => Self::Disallowed,
|
|
}
|
|
}
|
|
|
|
fn swap(&self, impl_trait_mode: &Self) {
|
|
match (self, impl_trait_mode) {
|
|
(Self::Opaque(x), Self::Opaque(y)) => x.swap(y),
|
|
(Self::Param(x), Self::Param(y)) => x.swap(y),
|
|
(Self::Variable(x), Self::Variable(y)) => x.swap(y),
|
|
(Self::Disallowed, Self::Disallowed) => (),
|
|
_ => panic!("mismatched lowering mode"),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
pub struct TyLoweringContext<'a> {
|
|
pub db: &'a dyn HirDatabase,
|
|
resolver: &'a Resolver,
|
|
in_binders: DebruijnIndex,
|
|
// FIXME: Should not be an `Option` but `Resolver` currently does not return owners in all cases
|
|
// where expected
|
|
owner: Option<TypeOwnerId>,
|
|
/// Note: Conceptually, it's thinkable that we could be in a location where
|
|
/// some type params should be represented as placeholders, and others
|
|
/// should be converted to variables. I think in practice, this isn't
|
|
/// possible currently, so this should be fine for now.
|
|
pub type_param_mode: ParamLoweringMode,
|
|
impl_trait_mode: ImplTraitLoweringState,
|
|
expander: RefCell<Option<Expander>>,
|
|
/// Tracks types with explicit `?Sized` bounds.
|
|
pub(crate) unsized_types: RefCell<FxHashSet<Ty>>,
|
|
}
|
|
|
|
impl<'a> TyLoweringContext<'a> {
|
|
pub fn new(db: &'a dyn HirDatabase, resolver: &'a Resolver, owner: TypeOwnerId) -> Self {
|
|
Self::new_maybe_unowned(db, resolver, Some(owner))
|
|
}
|
|
|
|
pub fn new_maybe_unowned(
|
|
db: &'a dyn HirDatabase,
|
|
resolver: &'a Resolver,
|
|
owner: Option<TypeOwnerId>,
|
|
) -> Self {
|
|
let impl_trait_mode = ImplTraitLoweringState::Disallowed;
|
|
let type_param_mode = ParamLoweringMode::Placeholder;
|
|
let in_binders = DebruijnIndex::INNERMOST;
|
|
Self {
|
|
db,
|
|
resolver,
|
|
owner,
|
|
in_binders,
|
|
impl_trait_mode,
|
|
type_param_mode,
|
|
expander: RefCell::new(None),
|
|
unsized_types: RefCell::default(),
|
|
}
|
|
}
|
|
|
|
pub fn with_debruijn<T>(
|
|
&self,
|
|
debruijn: DebruijnIndex,
|
|
f: impl FnOnce(&TyLoweringContext<'_>) -> T,
|
|
) -> T {
|
|
let impl_trait_mode = self.impl_trait_mode.take();
|
|
let expander = self.expander.take();
|
|
let unsized_types = self.unsized_types.take();
|
|
let new_ctx = Self {
|
|
in_binders: debruijn,
|
|
impl_trait_mode,
|
|
expander: RefCell::new(expander),
|
|
unsized_types: RefCell::new(unsized_types),
|
|
..*self
|
|
};
|
|
let result = f(&new_ctx);
|
|
self.impl_trait_mode.swap(&new_ctx.impl_trait_mode);
|
|
self.expander.replace(new_ctx.expander.into_inner());
|
|
self.unsized_types.replace(new_ctx.unsized_types.into_inner());
|
|
result
|
|
}
|
|
|
|
pub fn with_shifted_in<T>(
|
|
&self,
|
|
debruijn: DebruijnIndex,
|
|
f: impl FnOnce(&TyLoweringContext<'_>) -> T,
|
|
) -> T {
|
|
self.with_debruijn(self.in_binders.shifted_in_from(debruijn), f)
|
|
}
|
|
|
|
pub fn with_impl_trait_mode(self, impl_trait_mode: ImplTraitLoweringMode) -> Self {
|
|
Self { impl_trait_mode: ImplTraitLoweringState::new(impl_trait_mode), ..self }
|
|
}
|
|
|
|
pub fn with_type_param_mode(self, type_param_mode: ParamLoweringMode) -> Self {
|
|
Self { type_param_mode, ..self }
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
|
|
pub enum ImplTraitLoweringMode {
|
|
/// `impl Trait` gets lowered into an opaque type that doesn't unify with
|
|
/// anything except itself. This is used in places where values flow 'out',
|
|
/// i.e. for arguments of the function we're currently checking, and return
|
|
/// types of functions we're calling.
|
|
Opaque,
|
|
/// `impl Trait` gets lowered into a type variable. Used for argument
|
|
/// position impl Trait when inside the respective function, since it allows
|
|
/// us to support that without Chalk.
|
|
Param,
|
|
/// `impl Trait` gets lowered into a variable that can unify with some
|
|
/// type. This is used in places where values flow 'in', i.e. for arguments
|
|
/// of functions we're calling, and the return type of the function we're
|
|
/// currently checking.
|
|
Variable,
|
|
/// `impl Trait` is disallowed and will be an error.
|
|
Disallowed,
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
|
|
pub enum ParamLoweringMode {
|
|
Placeholder,
|
|
Variable,
|
|
}
|
|
|
|
impl<'a> TyLoweringContext<'a> {
|
|
pub fn lower_ty(&self, type_ref: &TypeRef) -> Ty {
|
|
self.lower_ty_ext(type_ref).0
|
|
}
|
|
|
|
pub fn lower_const(&self, const_ref: &ConstRef, const_type: Ty) -> Const {
|
|
let Some(owner) = self.owner else { return unknown_const(const_type) };
|
|
const_or_path_to_chalk(
|
|
self.db,
|
|
self.resolver,
|
|
owner,
|
|
const_type,
|
|
const_ref,
|
|
self.type_param_mode,
|
|
|| self.generics(),
|
|
self.in_binders,
|
|
)
|
|
}
|
|
|
|
fn generics(&self) -> Generics {
|
|
generics(
|
|
self.db.upcast(),
|
|
self.resolver
|
|
.generic_def()
|
|
.expect("there should be generics if there's a generic param"),
|
|
)
|
|
}
|
|
|
|
pub fn lower_ty_ext(&self, type_ref: &TypeRef) -> (Ty, Option<TypeNs>) {
|
|
let mut res = None;
|
|
let ty = match type_ref {
|
|
TypeRef::Never => TyKind::Never.intern(Interner),
|
|
TypeRef::Tuple(inner) => {
|
|
let inner_tys = inner.iter().map(|tr| self.lower_ty(tr));
|
|
TyKind::Tuple(inner_tys.len(), Substitution::from_iter(Interner, inner_tys))
|
|
.intern(Interner)
|
|
}
|
|
TypeRef::Path(path) => {
|
|
let (ty, res_) = self.lower_path(path);
|
|
res = res_;
|
|
ty
|
|
}
|
|
TypeRef::RawPtr(inner, mutability) => {
|
|
let inner_ty = self.lower_ty(inner);
|
|
TyKind::Raw(lower_to_chalk_mutability(*mutability), inner_ty).intern(Interner)
|
|
}
|
|
TypeRef::Array(inner, len) => {
|
|
let inner_ty = self.lower_ty(inner);
|
|
let const_len = self.lower_const(len, TyBuilder::usize());
|
|
TyKind::Array(inner_ty, const_len).intern(Interner)
|
|
}
|
|
TypeRef::Slice(inner) => {
|
|
let inner_ty = self.lower_ty(inner);
|
|
TyKind::Slice(inner_ty).intern(Interner)
|
|
}
|
|
TypeRef::Reference(inner, _, mutability) => {
|
|
let inner_ty = self.lower_ty(inner);
|
|
let lifetime = static_lifetime();
|
|
TyKind::Ref(lower_to_chalk_mutability(*mutability), lifetime, inner_ty)
|
|
.intern(Interner)
|
|
}
|
|
TypeRef::Placeholder => TyKind::Error.intern(Interner),
|
|
&TypeRef::Fn(ref params, variadic, is_unsafe, ref abi) => {
|
|
let substs = self.with_shifted_in(DebruijnIndex::ONE, |ctx| {
|
|
Substitution::from_iter(Interner, params.iter().map(|(_, tr)| ctx.lower_ty(tr)))
|
|
});
|
|
TyKind::Function(FnPointer {
|
|
num_binders: 0, // FIXME lower `for<'a> fn()` correctly
|
|
sig: FnSig {
|
|
abi: abi.as_deref().map_or(FnAbi::Rust, FnAbi::from_str),
|
|
safety: if is_unsafe { Safety::Unsafe } else { Safety::Safe },
|
|
variadic,
|
|
},
|
|
substitution: FnSubst(substs),
|
|
})
|
|
.intern(Interner)
|
|
}
|
|
TypeRef::DynTrait(bounds) => self.lower_dyn_trait(bounds),
|
|
TypeRef::ImplTrait(bounds) => {
|
|
match &self.impl_trait_mode {
|
|
ImplTraitLoweringState::Opaque(opaque_type_data) => {
|
|
let func = match self.resolver.generic_def() {
|
|
Some(GenericDefId::FunctionId(f)) => f,
|
|
_ => panic!("opaque impl trait lowering in non-function"),
|
|
};
|
|
|
|
// this dance is to make sure the data is in the right
|
|
// place even if we encounter more opaque types while
|
|
// lowering the bounds
|
|
let idx = opaque_type_data.borrow_mut().alloc(ReturnTypeImplTrait {
|
|
bounds: crate::make_single_type_binders(Vec::new()),
|
|
});
|
|
// We don't want to lower the bounds inside the binders
|
|
// we're currently in, because they don't end up inside
|
|
// those binders. E.g. when we have `impl Trait<impl
|
|
// OtherTrait<T>>`, the `impl OtherTrait<T>` can't refer
|
|
// to the self parameter from `impl Trait`, and the
|
|
// bounds aren't actually stored nested within each
|
|
// other, but separately. So if the `T` refers to a type
|
|
// parameter of the outer function, it's just one binder
|
|
// away instead of two.
|
|
let actual_opaque_type_data = self
|
|
.with_debruijn(DebruijnIndex::INNERMOST, |ctx| {
|
|
ctx.lower_impl_trait(bounds, func)
|
|
});
|
|
opaque_type_data.borrow_mut()[idx] = actual_opaque_type_data;
|
|
|
|
let impl_trait_id = ImplTraitId::ReturnTypeImplTrait(func, idx);
|
|
let opaque_ty_id = self.db.intern_impl_trait_id(impl_trait_id).into();
|
|
let generics = generics(self.db.upcast(), func.into());
|
|
let parameters = generics.bound_vars_subst(self.db, self.in_binders);
|
|
TyKind::OpaqueType(opaque_ty_id, parameters).intern(Interner)
|
|
}
|
|
ImplTraitLoweringState::Param(counter) => {
|
|
let idx = counter.get();
|
|
// FIXME we're probably doing something wrong here
|
|
counter.set(idx + count_impl_traits(type_ref) as u16);
|
|
if let Some(def) = self.resolver.generic_def() {
|
|
let generics = generics(self.db.upcast(), def);
|
|
let param = generics
|
|
.iter()
|
|
.filter(|(_, data)| {
|
|
matches!(
|
|
data,
|
|
TypeOrConstParamData::TypeParamData(data)
|
|
if data.provenance == TypeParamProvenance::ArgumentImplTrait
|
|
)
|
|
})
|
|
.nth(idx as usize)
|
|
.map_or(TyKind::Error, |(id, _)| {
|
|
TyKind::Placeholder(to_placeholder_idx(self.db, id))
|
|
});
|
|
param.intern(Interner)
|
|
} else {
|
|
TyKind::Error.intern(Interner)
|
|
}
|
|
}
|
|
ImplTraitLoweringState::Variable(counter) => {
|
|
let idx = counter.get();
|
|
// FIXME we're probably doing something wrong here
|
|
counter.set(idx + count_impl_traits(type_ref) as u16);
|
|
let (
|
|
_parent_params,
|
|
self_params,
|
|
list_params,
|
|
const_params,
|
|
_impl_trait_params,
|
|
) = if let Some(def) = self.resolver.generic_def() {
|
|
let generics = generics(self.db.upcast(), def);
|
|
generics.provenance_split()
|
|
} else {
|
|
(0, 0, 0, 0, 0)
|
|
};
|
|
TyKind::BoundVar(BoundVar::new(
|
|
self.in_binders,
|
|
idx as usize + self_params + list_params + const_params,
|
|
))
|
|
.intern(Interner)
|
|
}
|
|
ImplTraitLoweringState::Disallowed => {
|
|
// FIXME: report error
|
|
TyKind::Error.intern(Interner)
|
|
}
|
|
}
|
|
}
|
|
TypeRef::Macro(macro_call) => {
|
|
let (mut expander, recursion_start) = {
|
|
match RefMut::filter_map(self.expander.borrow_mut(), Option::as_mut) {
|
|
// There already is an expander here, this means we are already recursing
|
|
Ok(expander) => (expander, false),
|
|
// No expander was created yet, so we are at the start of the expansion recursion
|
|
// and therefore have to create an expander.
|
|
Err(expander) => (
|
|
RefMut::map(expander, |it| {
|
|
it.insert(Expander::new(
|
|
self.db.upcast(),
|
|
macro_call.file_id,
|
|
self.resolver.module(),
|
|
))
|
|
}),
|
|
true,
|
|
),
|
|
}
|
|
};
|
|
let ty = {
|
|
let macro_call = macro_call.to_node(self.db.upcast());
|
|
let resolver = |path| {
|
|
self.resolver
|
|
.resolve_path_as_macro(self.db.upcast(), &path, Some(MacroSubNs::Bang))
|
|
.map(|(it, _)| it)
|
|
};
|
|
match expander.enter_expand::<ast::Type>(self.db.upcast(), macro_call, resolver)
|
|
{
|
|
Ok(ExpandResult { value: Some((mark, expanded)), .. }) => {
|
|
let ctx = expander.ctx(self.db.upcast());
|
|
// FIXME: Report syntax errors in expansion here
|
|
let type_ref = TypeRef::from_ast(&ctx, expanded.tree());
|
|
|
|
drop(expander);
|
|
let ty = self.lower_ty(&type_ref);
|
|
|
|
self.expander.borrow_mut().as_mut().unwrap().exit(mark);
|
|
Some(ty)
|
|
}
|
|
_ => {
|
|
drop(expander);
|
|
None
|
|
}
|
|
}
|
|
};
|
|
|
|
// drop the expander, resetting it to pre-recursion state
|
|
if recursion_start {
|
|
*self.expander.borrow_mut() = None;
|
|
}
|
|
ty.unwrap_or_else(|| TyKind::Error.intern(Interner))
|
|
}
|
|
TypeRef::Error => TyKind::Error.intern(Interner),
|
|
};
|
|
(ty, res)
|
|
}
|
|
|
|
/// This is only for `generic_predicates_for_param`, where we can't just
|
|
/// lower the self types of the predicates since that could lead to cycles.
|
|
/// So we just check here if the `type_ref` resolves to a generic param, and which.
|
|
fn lower_ty_only_param(&self, type_ref: &TypeRef) -> Option<TypeOrConstParamId> {
|
|
let path = match type_ref {
|
|
TypeRef::Path(path) => path,
|
|
_ => return None,
|
|
};
|
|
if path.type_anchor().is_some() {
|
|
return None;
|
|
}
|
|
if path.segments().len() > 1 {
|
|
return None;
|
|
}
|
|
let resolution = match self.resolver.resolve_path_in_type_ns(self.db.upcast(), path) {
|
|
Some((it, None, _)) => it,
|
|
_ => return None,
|
|
};
|
|
match resolution {
|
|
TypeNs::GenericParam(param_id) => Some(param_id.into()),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
pub(crate) fn lower_ty_relative_path(
|
|
&self,
|
|
ty: Ty,
|
|
// We need the original resolution to lower `Self::AssocTy` correctly
|
|
res: Option<TypeNs>,
|
|
remaining_segments: PathSegments<'_>,
|
|
) -> (Ty, Option<TypeNs>) {
|
|
match remaining_segments.len() {
|
|
0 => (ty, res),
|
|
1 => {
|
|
// resolve unselected assoc types
|
|
let segment = remaining_segments.first().unwrap();
|
|
(self.select_associated_type(res, segment), None)
|
|
}
|
|
_ => {
|
|
// FIXME report error (ambiguous associated type)
|
|
(TyKind::Error.intern(Interner), None)
|
|
}
|
|
}
|
|
}
|
|
|
|
pub(crate) fn lower_partly_resolved_path(
|
|
&self,
|
|
resolution: TypeNs,
|
|
resolved_segment: PathSegment<'_>,
|
|
remaining_segments: PathSegments<'_>,
|
|
infer_args: bool,
|
|
) -> (Ty, Option<TypeNs>) {
|
|
let ty = match resolution {
|
|
TypeNs::TraitId(trait_) => {
|
|
let ty = match remaining_segments.len() {
|
|
1 => {
|
|
let trait_ref =
|
|
self.lower_trait_ref_from_resolved_path(trait_, resolved_segment, None);
|
|
let segment = remaining_segments.first().unwrap();
|
|
let found = self
|
|
.db
|
|
.trait_data(trait_ref.hir_trait_id())
|
|
.associated_type_by_name(segment.name);
|
|
|
|
match found {
|
|
Some(associated_ty) => {
|
|
// FIXME: `substs_from_path_segment()` pushes `TyKind::Error` for every parent
|
|
// generic params. It's inefficient to splice the `Substitution`s, so we may want
|
|
// that method to optionally take parent `Substitution` as we already know them at
|
|
// this point (`trait_ref.substitution`).
|
|
let substitution = self.substs_from_path_segment(
|
|
segment,
|
|
Some(associated_ty.into()),
|
|
false,
|
|
None,
|
|
);
|
|
let len_self =
|
|
generics(self.db.upcast(), associated_ty.into()).len_self();
|
|
let substitution = Substitution::from_iter(
|
|
Interner,
|
|
substitution
|
|
.iter(Interner)
|
|
.take(len_self)
|
|
.chain(trait_ref.substitution.iter(Interner)),
|
|
);
|
|
TyKind::Alias(AliasTy::Projection(ProjectionTy {
|
|
associated_ty_id: to_assoc_type_id(associated_ty),
|
|
substitution,
|
|
}))
|
|
.intern(Interner)
|
|
}
|
|
None => {
|
|
// FIXME: report error (associated type not found)
|
|
TyKind::Error.intern(Interner)
|
|
}
|
|
}
|
|
}
|
|
0 => {
|
|
// Trait object type without dyn; this should be handled in upstream. See
|
|
// `lower_path()`.
|
|
stdx::never!("unexpected fully resolved trait path");
|
|
TyKind::Error.intern(Interner)
|
|
}
|
|
_ => {
|
|
// FIXME report error (ambiguous associated type)
|
|
TyKind::Error.intern(Interner)
|
|
}
|
|
};
|
|
return (ty, None);
|
|
}
|
|
TypeNs::TraitAliasId(_) => {
|
|
// FIXME(trait_alias): Implement trait alias.
|
|
return (TyKind::Error.intern(Interner), None);
|
|
}
|
|
TypeNs::GenericParam(param_id) => {
|
|
let generics = generics(
|
|
self.db.upcast(),
|
|
self.resolver.generic_def().expect("generics in scope"),
|
|
);
|
|
match self.type_param_mode {
|
|
ParamLoweringMode::Placeholder => {
|
|
TyKind::Placeholder(to_placeholder_idx(self.db, param_id.into()))
|
|
}
|
|
ParamLoweringMode::Variable => {
|
|
let idx = match generics.param_idx(param_id.into()) {
|
|
None => {
|
|
never!("no matching generics");
|
|
return (TyKind::Error.intern(Interner), None);
|
|
}
|
|
Some(idx) => idx,
|
|
};
|
|
|
|
TyKind::BoundVar(BoundVar::new(self.in_binders, idx))
|
|
}
|
|
}
|
|
.intern(Interner)
|
|
}
|
|
TypeNs::SelfType(impl_id) => {
|
|
let def =
|
|
self.resolver.generic_def().expect("impl should have generic param scope");
|
|
let generics = generics(self.db.upcast(), def);
|
|
|
|
match self.type_param_mode {
|
|
ParamLoweringMode::Placeholder => {
|
|
// `def` can be either impl itself or item within, and we need impl itself
|
|
// now.
|
|
let generics = generics.parent_generics().unwrap_or(&generics);
|
|
let subst = generics.placeholder_subst(self.db);
|
|
self.db.impl_self_ty(impl_id).substitute(Interner, &subst)
|
|
}
|
|
ParamLoweringMode::Variable => {
|
|
let starting_from = match def {
|
|
GenericDefId::ImplId(_) => 0,
|
|
// `def` is an item within impl. We need to substitute `BoundVar`s but
|
|
// remember that they are for parent (i.e. impl) generic params so they
|
|
// come after our own params.
|
|
_ => generics.len_self(),
|
|
};
|
|
TyBuilder::impl_self_ty(self.db, impl_id)
|
|
.fill_with_bound_vars(self.in_binders, starting_from)
|
|
.build()
|
|
}
|
|
}
|
|
}
|
|
TypeNs::AdtSelfType(adt) => {
|
|
let generics = generics(self.db.upcast(), adt.into());
|
|
let substs = match self.type_param_mode {
|
|
ParamLoweringMode::Placeholder => generics.placeholder_subst(self.db),
|
|
ParamLoweringMode::Variable => {
|
|
generics.bound_vars_subst(self.db, self.in_binders)
|
|
}
|
|
};
|
|
self.db.ty(adt.into()).substitute(Interner, &substs)
|
|
}
|
|
|
|
TypeNs::AdtId(it) => self.lower_path_inner(resolved_segment, it.into(), infer_args),
|
|
TypeNs::BuiltinType(it) => {
|
|
self.lower_path_inner(resolved_segment, it.into(), infer_args)
|
|
}
|
|
TypeNs::TypeAliasId(it) => {
|
|
self.lower_path_inner(resolved_segment, it.into(), infer_args)
|
|
}
|
|
// FIXME: report error
|
|
TypeNs::EnumVariantId(_) => return (TyKind::Error.intern(Interner), None),
|
|
};
|
|
self.lower_ty_relative_path(ty, Some(resolution), remaining_segments)
|
|
}
|
|
|
|
pub(crate) fn lower_path(&self, path: &Path) -> (Ty, Option<TypeNs>) {
|
|
// Resolve the path (in type namespace)
|
|
if let Some(type_ref) = path.type_anchor() {
|
|
let (ty, res) = self.lower_ty_ext(type_ref);
|
|
return self.lower_ty_relative_path(ty, res, path.segments());
|
|
}
|
|
|
|
let (resolution, remaining_index, _) =
|
|
match self.resolver.resolve_path_in_type_ns(self.db.upcast(), path) {
|
|
Some(it) => it,
|
|
None => return (TyKind::Error.intern(Interner), None),
|
|
};
|
|
|
|
if matches!(resolution, TypeNs::TraitId(_)) && remaining_index.is_none() {
|
|
// trait object type without dyn
|
|
let bound = TypeBound::Path(path.clone(), TraitBoundModifier::None);
|
|
let ty = self.lower_dyn_trait(&[Interned::new(bound)]);
|
|
return (ty, None);
|
|
}
|
|
|
|
let (resolved_segment, remaining_segments) = match remaining_index {
|
|
None => (
|
|
path.segments().last().expect("resolved path has at least one element"),
|
|
PathSegments::EMPTY,
|
|
),
|
|
Some(i) => (path.segments().get(i - 1).unwrap(), path.segments().skip(i)),
|
|
};
|
|
self.lower_partly_resolved_path(resolution, resolved_segment, remaining_segments, false)
|
|
}
|
|
|
|
fn select_associated_type(&self, res: Option<TypeNs>, segment: PathSegment<'_>) -> Ty {
|
|
let Some((def, res)) = self.resolver.generic_def().zip(res) else {
|
|
return TyKind::Error.intern(Interner);
|
|
};
|
|
let ty = named_associated_type_shorthand_candidates(
|
|
self.db,
|
|
def,
|
|
res,
|
|
Some(segment.name.clone()),
|
|
move |name, t, associated_ty| {
|
|
if name != segment.name {
|
|
return None;
|
|
}
|
|
|
|
let parent_subst = t.substitution.clone();
|
|
let parent_subst = match self.type_param_mode {
|
|
ParamLoweringMode::Placeholder => {
|
|
// if we're lowering to placeholders, we have to put them in now.
|
|
let generics = generics(self.db.upcast(), def);
|
|
let s = generics.placeholder_subst(self.db);
|
|
s.apply(parent_subst, Interner)
|
|
}
|
|
ParamLoweringMode::Variable => {
|
|
// We need to shift in the bound vars, since
|
|
// `named_associated_type_shorthand_candidates` does not do that.
|
|
parent_subst.shifted_in_from(Interner, self.in_binders)
|
|
}
|
|
};
|
|
|
|
// FIXME: `substs_from_path_segment()` pushes `TyKind::Error` for every parent
|
|
// generic params. It's inefficient to splice the `Substitution`s, so we may want
|
|
// that method to optionally take parent `Substitution` as we already know them at
|
|
// this point (`t.substitution`).
|
|
let substs = self.substs_from_path_segment(
|
|
segment.clone(),
|
|
Some(associated_ty.into()),
|
|
false,
|
|
None,
|
|
);
|
|
|
|
let len_self = generics(self.db.upcast(), associated_ty.into()).len_self();
|
|
|
|
let substs = Substitution::from_iter(
|
|
Interner,
|
|
substs.iter(Interner).take(len_self).chain(parent_subst.iter(Interner)),
|
|
);
|
|
|
|
Some(
|
|
TyKind::Alias(AliasTy::Projection(ProjectionTy {
|
|
associated_ty_id: to_assoc_type_id(associated_ty),
|
|
substitution: substs,
|
|
}))
|
|
.intern(Interner),
|
|
)
|
|
},
|
|
);
|
|
|
|
ty.unwrap_or_else(|| TyKind::Error.intern(Interner))
|
|
}
|
|
|
|
fn lower_path_inner(
|
|
&self,
|
|
segment: PathSegment<'_>,
|
|
typeable: TyDefId,
|
|
infer_args: bool,
|
|
) -> Ty {
|
|
let generic_def = match typeable {
|
|
TyDefId::BuiltinType(_) => None,
|
|
TyDefId::AdtId(it) => Some(it.into()),
|
|
TyDefId::TypeAliasId(it) => Some(it.into()),
|
|
};
|
|
let substs = self.substs_from_path_segment(segment, generic_def, infer_args, None);
|
|
self.db.ty(typeable).substitute(Interner, &substs)
|
|
}
|
|
|
|
/// Collect generic arguments from a path into a `Substs`. See also
|
|
/// `create_substs_for_ast_path` and `def_to_ty` in rustc.
|
|
pub(super) fn substs_from_path(
|
|
&self,
|
|
path: &Path,
|
|
// Note that we don't call `db.value_type(resolved)` here,
|
|
// `ValueTyDefId` is just a convenient way to pass generics and
|
|
// special-case enum variants
|
|
resolved: ValueTyDefId,
|
|
infer_args: bool,
|
|
) -> Substitution {
|
|
let last = path.segments().last();
|
|
let (segment, generic_def) = match resolved {
|
|
ValueTyDefId::FunctionId(it) => (last, Some(it.into())),
|
|
ValueTyDefId::StructId(it) => (last, Some(it.into())),
|
|
ValueTyDefId::UnionId(it) => (last, Some(it.into())),
|
|
ValueTyDefId::ConstId(it) => (last, Some(it.into())),
|
|
ValueTyDefId::StaticId(_) => (last, None),
|
|
ValueTyDefId::EnumVariantId(var) => {
|
|
// the generic args for an enum variant may be either specified
|
|
// on the segment referring to the enum, or on the segment
|
|
// referring to the variant. So `Option::<T>::None` and
|
|
// `Option::None::<T>` are both allowed (though the former is
|
|
// preferred). See also `def_ids_for_path_segments` in rustc.
|
|
let len = path.segments().len();
|
|
let penultimate = len.checked_sub(2).and_then(|idx| path.segments().get(idx));
|
|
let segment = match penultimate {
|
|
Some(segment) if segment.args_and_bindings.is_some() => Some(segment),
|
|
_ => last,
|
|
};
|
|
(segment, Some(var.lookup(self.db.upcast()).parent.into()))
|
|
}
|
|
};
|
|
if let Some(segment) = segment {
|
|
self.substs_from_path_segment(segment, generic_def, infer_args, None)
|
|
} else if let Some(generic_def) = generic_def {
|
|
// lang item
|
|
self.substs_from_args_and_bindings(None, Some(generic_def), infer_args, None)
|
|
} else {
|
|
Substitution::empty(Interner)
|
|
}
|
|
}
|
|
|
|
pub(super) fn substs_from_path_segment(
|
|
&self,
|
|
segment: PathSegment<'_>,
|
|
def: Option<GenericDefId>,
|
|
infer_args: bool,
|
|
explicit_self_ty: Option<Ty>,
|
|
) -> Substitution {
|
|
self.substs_from_args_and_bindings(
|
|
segment.args_and_bindings,
|
|
def,
|
|
infer_args,
|
|
explicit_self_ty,
|
|
)
|
|
}
|
|
|
|
fn substs_from_args_and_bindings(
|
|
&self,
|
|
args_and_bindings: Option<&GenericArgs>,
|
|
def: Option<GenericDefId>,
|
|
infer_args: bool,
|
|
explicit_self_ty: Option<Ty>,
|
|
) -> Substitution {
|
|
// Remember that the item's own generic args come before its parent's.
|
|
let mut substs = Vec::new();
|
|
let def = if let Some(d) = def {
|
|
d
|
|
} else {
|
|
return Substitution::empty(Interner);
|
|
};
|
|
let def_generics = generics(self.db.upcast(), def);
|
|
let (parent_params, self_params, type_params, const_params, impl_trait_params) =
|
|
def_generics.provenance_split();
|
|
let item_len = self_params + type_params + const_params + impl_trait_params;
|
|
let total_len = parent_params + item_len;
|
|
|
|
let ty_error = TyKind::Error.intern(Interner).cast(Interner);
|
|
|
|
let mut def_generic_iter = def_generics.iter_id();
|
|
|
|
let fill_self_params = || {
|
|
for x in explicit_self_ty
|
|
.into_iter()
|
|
.map(|x| x.cast(Interner))
|
|
.chain(iter::repeat(ty_error.clone()))
|
|
.take(self_params)
|
|
{
|
|
if let Some(id) = def_generic_iter.next() {
|
|
assert!(id.is_left());
|
|
substs.push(x);
|
|
}
|
|
}
|
|
};
|
|
let mut had_explicit_args = false;
|
|
|
|
if let Some(generic_args) = &args_and_bindings {
|
|
if !generic_args.has_self_type {
|
|
fill_self_params();
|
|
}
|
|
let expected_num = if generic_args.has_self_type {
|
|
self_params + type_params + const_params
|
|
} else {
|
|
type_params + const_params
|
|
};
|
|
let skip = if generic_args.has_self_type && self_params == 0 { 1 } else { 0 };
|
|
// if args are provided, it should be all of them, but we can't rely on that
|
|
for arg in generic_args
|
|
.args
|
|
.iter()
|
|
.filter(|arg| !matches!(arg, GenericArg::Lifetime(_)))
|
|
.skip(skip)
|
|
.take(expected_num)
|
|
{
|
|
if let Some(id) = def_generic_iter.next() {
|
|
if let Some(x) = generic_arg_to_chalk(
|
|
self.db,
|
|
id,
|
|
arg,
|
|
&mut (),
|
|
|_, type_ref| self.lower_ty(type_ref),
|
|
|_, const_ref, ty| self.lower_const(const_ref, ty),
|
|
) {
|
|
had_explicit_args = true;
|
|
substs.push(x);
|
|
} else {
|
|
// we just filtered them out
|
|
never!("Unexpected lifetime argument");
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
fill_self_params();
|
|
}
|
|
|
|
// These params include those of parent.
|
|
let remaining_params: SmallVec<[_; 2]> = def_generic_iter
|
|
.map(|eid| match eid {
|
|
Either::Left(_) => ty_error.clone(),
|
|
Either::Right(x) => unknown_const_as_generic(self.db.const_param_ty(x)),
|
|
})
|
|
.collect();
|
|
assert_eq!(remaining_params.len() + substs.len(), total_len);
|
|
|
|
// handle defaults. In expression or pattern path segments without
|
|
// explicitly specified type arguments, missing type arguments are inferred
|
|
// (i.e. defaults aren't used).
|
|
// Generic parameters for associated types are not supposed to have defaults, so we just
|
|
// ignore them.
|
|
let is_assoc_ty = if let GenericDefId::TypeAliasId(id) = def {
|
|
let container = id.lookup(self.db.upcast()).container;
|
|
matches!(container, ItemContainerId::TraitId(_))
|
|
} else {
|
|
false
|
|
};
|
|
if !is_assoc_ty && (!infer_args || had_explicit_args) {
|
|
let defaults = self.db.generic_defaults(def);
|
|
assert_eq!(total_len, defaults.len());
|
|
let parent_from = item_len - substs.len();
|
|
|
|
for (idx, default_ty) in defaults[substs.len()..item_len].iter().enumerate() {
|
|
// each default can depend on the previous parameters
|
|
let substs_so_far = Substitution::from_iter(
|
|
Interner,
|
|
substs.iter().cloned().chain(remaining_params[idx..].iter().cloned()),
|
|
);
|
|
substs.push(default_ty.clone().substitute(Interner, &substs_so_far));
|
|
}
|
|
|
|
// Keep parent's params as unknown.
|
|
let mut remaining_params = remaining_params;
|
|
substs.extend(remaining_params.drain(parent_from..));
|
|
} else {
|
|
substs.extend(remaining_params);
|
|
}
|
|
|
|
assert_eq!(substs.len(), total_len);
|
|
Substitution::from_iter(Interner, substs)
|
|
}
|
|
|
|
fn lower_trait_ref_from_path(
|
|
&self,
|
|
path: &Path,
|
|
explicit_self_ty: Option<Ty>,
|
|
) -> Option<TraitRef> {
|
|
let resolved = match self.resolver.resolve_path_in_type_ns_fully(self.db.upcast(), path)? {
|
|
// FIXME(trait_alias): We need to handle trait alias here.
|
|
TypeNs::TraitId(tr) => tr,
|
|
_ => return None,
|
|
};
|
|
let segment = path.segments().last().expect("path should have at least one segment");
|
|
Some(self.lower_trait_ref_from_resolved_path(resolved, segment, explicit_self_ty))
|
|
}
|
|
|
|
pub(crate) fn lower_trait_ref_from_resolved_path(
|
|
&self,
|
|
resolved: TraitId,
|
|
segment: PathSegment<'_>,
|
|
explicit_self_ty: Option<Ty>,
|
|
) -> TraitRef {
|
|
let substs = self.trait_ref_substs_from_path(segment, resolved, explicit_self_ty);
|
|
TraitRef { trait_id: to_chalk_trait_id(resolved), substitution: substs }
|
|
}
|
|
|
|
fn lower_trait_ref(
|
|
&self,
|
|
trait_ref: &HirTraitRef,
|
|
explicit_self_ty: Option<Ty>,
|
|
) -> Option<TraitRef> {
|
|
self.lower_trait_ref_from_path(&trait_ref.path, explicit_self_ty)
|
|
}
|
|
|
|
fn trait_ref_substs_from_path(
|
|
&self,
|
|
segment: PathSegment<'_>,
|
|
resolved: TraitId,
|
|
explicit_self_ty: Option<Ty>,
|
|
) -> Substitution {
|
|
self.substs_from_path_segment(segment, Some(resolved.into()), false, explicit_self_ty)
|
|
}
|
|
|
|
pub(crate) fn lower_where_predicate(
|
|
&self,
|
|
where_predicate: &WherePredicate,
|
|
ignore_bindings: bool,
|
|
) -> impl Iterator<Item = QuantifiedWhereClause> {
|
|
match where_predicate {
|
|
WherePredicate::ForLifetime { target, bound, .. }
|
|
| WherePredicate::TypeBound { target, bound } => {
|
|
let self_ty = match target {
|
|
WherePredicateTypeTarget::TypeRef(type_ref) => self.lower_ty(type_ref),
|
|
WherePredicateTypeTarget::TypeOrConstParam(param_id) => {
|
|
let generic_def = self.resolver.generic_def().expect("generics in scope");
|
|
let generics = generics(self.db.upcast(), generic_def);
|
|
let param_id = hir_def::TypeOrConstParamId {
|
|
parent: generic_def,
|
|
local_id: *param_id,
|
|
};
|
|
let placeholder = to_placeholder_idx(self.db, param_id);
|
|
match self.type_param_mode {
|
|
ParamLoweringMode::Placeholder => TyKind::Placeholder(placeholder),
|
|
ParamLoweringMode::Variable => {
|
|
let idx = generics.param_idx(param_id).expect("matching generics");
|
|
TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, idx))
|
|
}
|
|
}
|
|
.intern(Interner)
|
|
}
|
|
};
|
|
self.lower_type_bound(bound, self_ty, ignore_bindings)
|
|
.collect::<Vec<_>>()
|
|
.into_iter()
|
|
}
|
|
WherePredicate::Lifetime { .. } => vec![].into_iter(),
|
|
}
|
|
}
|
|
|
|
pub(crate) fn lower_type_bound(
|
|
&'a self,
|
|
bound: &'a Interned<TypeBound>,
|
|
self_ty: Ty,
|
|
ignore_bindings: bool,
|
|
) -> impl Iterator<Item = QuantifiedWhereClause> + 'a {
|
|
let mut bindings = None;
|
|
let trait_ref = match bound.as_ref() {
|
|
TypeBound::Path(path, TraitBoundModifier::None) => {
|
|
bindings = self.lower_trait_ref_from_path(path, Some(self_ty));
|
|
bindings
|
|
.clone()
|
|
.filter(|tr| {
|
|
// ignore `T: Drop` or `T: Destruct` bounds.
|
|
// - `T: ~const Drop` has a special meaning in Rust 1.61 that we don't implement.
|
|
// (So ideally, we'd only ignore `~const Drop` here)
|
|
// - `Destruct` impls are built-in in 1.62 (current nightly as of 08-04-2022), so until
|
|
// the builtin impls are supported by Chalk, we ignore them here.
|
|
if let Some(lang) = self.db.lang_attr(tr.hir_trait_id().into()) {
|
|
if matches!(lang, LangItem::Drop | LangItem::Destruct) {
|
|
return false;
|
|
}
|
|
}
|
|
true
|
|
})
|
|
.map(WhereClause::Implemented)
|
|
.map(crate::wrap_empty_binders)
|
|
}
|
|
TypeBound::Path(path, TraitBoundModifier::Maybe) => {
|
|
let sized_trait = self
|
|
.db
|
|
.lang_item(self.resolver.krate(), LangItem::Sized)
|
|
.and_then(|lang_item| lang_item.as_trait());
|
|
// Don't lower associated type bindings as the only possible relaxed trait bound
|
|
// `?Sized` has no of them.
|
|
// If we got another trait here ignore the bound completely.
|
|
let trait_id = self
|
|
.lower_trait_ref_from_path(path, Some(self_ty.clone()))
|
|
.map(|trait_ref| trait_ref.hir_trait_id());
|
|
if trait_id == sized_trait {
|
|
self.unsized_types.borrow_mut().insert(self_ty);
|
|
}
|
|
None
|
|
}
|
|
TypeBound::ForLifetime(_, path) => {
|
|
// FIXME Don't silently drop the hrtb lifetimes here
|
|
bindings = self.lower_trait_ref_from_path(path, Some(self_ty));
|
|
bindings.clone().map(WhereClause::Implemented).map(crate::wrap_empty_binders)
|
|
}
|
|
TypeBound::Lifetime(_) => None,
|
|
TypeBound::Error => None,
|
|
};
|
|
trait_ref.into_iter().chain(
|
|
bindings
|
|
.into_iter()
|
|
.filter(move |_| !ignore_bindings)
|
|
.flat_map(move |tr| self.assoc_type_bindings_from_type_bound(bound, tr)),
|
|
)
|
|
}
|
|
|
|
fn assoc_type_bindings_from_type_bound(
|
|
&'a self,
|
|
bound: &'a Interned<TypeBound>,
|
|
trait_ref: TraitRef,
|
|
) -> impl Iterator<Item = QuantifiedWhereClause> + 'a {
|
|
let last_segment = match bound.as_ref() {
|
|
TypeBound::Path(path, TraitBoundModifier::None) | TypeBound::ForLifetime(_, path) => {
|
|
path.segments().last()
|
|
}
|
|
TypeBound::Path(_, TraitBoundModifier::Maybe)
|
|
| TypeBound::Error
|
|
| TypeBound::Lifetime(_) => None,
|
|
};
|
|
last_segment
|
|
.into_iter()
|
|
.filter_map(|segment| segment.args_and_bindings)
|
|
.flat_map(|args_and_bindings| args_and_bindings.bindings.iter())
|
|
.flat_map(move |binding| {
|
|
let found = associated_type_by_name_including_super_traits(
|
|
self.db,
|
|
trait_ref.clone(),
|
|
&binding.name,
|
|
);
|
|
let (super_trait_ref, associated_ty) = match found {
|
|
None => return SmallVec::new(),
|
|
Some(t) => t,
|
|
};
|
|
// FIXME: `substs_from_path_segment()` pushes `TyKind::Error` for every parent
|
|
// generic params. It's inefficient to splice the `Substitution`s, so we may want
|
|
// that method to optionally take parent `Substitution` as we already know them at
|
|
// this point (`super_trait_ref.substitution`).
|
|
let substitution = self.substs_from_path_segment(
|
|
// FIXME: This is hack. We shouldn't really build `PathSegment` directly.
|
|
PathSegment { name: &binding.name, args_and_bindings: binding.args.as_deref() },
|
|
Some(associated_ty.into()),
|
|
false, // this is not relevant
|
|
Some(super_trait_ref.self_type_parameter(Interner)),
|
|
);
|
|
let self_params = generics(self.db.upcast(), associated_ty.into()).len_self();
|
|
let substitution = Substitution::from_iter(
|
|
Interner,
|
|
substitution
|
|
.iter(Interner)
|
|
.take(self_params)
|
|
.chain(super_trait_ref.substitution.iter(Interner)),
|
|
);
|
|
let projection_ty = ProjectionTy {
|
|
associated_ty_id: to_assoc_type_id(associated_ty),
|
|
substitution,
|
|
};
|
|
let mut predicates: SmallVec<[_; 1]> = SmallVec::with_capacity(
|
|
binding.type_ref.as_ref().map_or(0, |_| 1) + binding.bounds.len(),
|
|
);
|
|
if let Some(type_ref) = &binding.type_ref {
|
|
if let (TypeRef::ImplTrait(bounds), ImplTraitLoweringState::Disallowed) =
|
|
(type_ref, &self.impl_trait_mode)
|
|
{
|
|
for bound in bounds {
|
|
predicates.extend(
|
|
self.lower_type_bound(
|
|
bound,
|
|
TyKind::Alias(AliasTy::Projection(projection_ty.clone()))
|
|
.intern(Interner),
|
|
false,
|
|
),
|
|
);
|
|
}
|
|
} else {
|
|
let ty = 'ty: {
|
|
if matches!(
|
|
self.impl_trait_mode,
|
|
ImplTraitLoweringState::Param(_)
|
|
| ImplTraitLoweringState::Variable(_)
|
|
) {
|
|
// Find the generic index for the target of our `bound`
|
|
let target_param_idx = self
|
|
.resolver
|
|
.where_predicates_in_scope()
|
|
.find_map(|p| match p {
|
|
WherePredicate::TypeBound {
|
|
target: WherePredicateTypeTarget::TypeOrConstParam(idx),
|
|
bound: b,
|
|
} if b == bound => Some(idx),
|
|
_ => None,
|
|
});
|
|
if let Some(target_param_idx) = target_param_idx {
|
|
let mut counter = 0;
|
|
for (idx, data) in self.generics().params.type_or_consts.iter()
|
|
{
|
|
// Count the number of `impl Trait` things that appear before
|
|
// the target of our `bound`.
|
|
// Our counter within `impl_trait_mode` should be that number
|
|
// to properly lower each types within `type_ref`
|
|
if data.type_param().is_some_and(|p| {
|
|
p.provenance == TypeParamProvenance::ArgumentImplTrait
|
|
}) {
|
|
counter += 1;
|
|
}
|
|
if idx == *target_param_idx {
|
|
break;
|
|
}
|
|
}
|
|
let mut ext = TyLoweringContext::new_maybe_unowned(
|
|
self.db,
|
|
self.resolver,
|
|
self.owner,
|
|
)
|
|
.with_type_param_mode(self.type_param_mode);
|
|
match &self.impl_trait_mode {
|
|
ImplTraitLoweringState::Param(_) => {
|
|
ext.impl_trait_mode =
|
|
ImplTraitLoweringState::Param(Cell::new(counter));
|
|
}
|
|
ImplTraitLoweringState::Variable(_) => {
|
|
ext.impl_trait_mode = ImplTraitLoweringState::Variable(
|
|
Cell::new(counter),
|
|
);
|
|
}
|
|
_ => unreachable!(),
|
|
}
|
|
break 'ty ext.lower_ty(type_ref);
|
|
}
|
|
}
|
|
self.lower_ty(type_ref)
|
|
};
|
|
let alias_eq =
|
|
AliasEq { alias: AliasTy::Projection(projection_ty.clone()), ty };
|
|
predicates.push(crate::wrap_empty_binders(WhereClause::AliasEq(alias_eq)));
|
|
}
|
|
}
|
|
for bound in binding.bounds.iter() {
|
|
predicates.extend(self.lower_type_bound(
|
|
bound,
|
|
TyKind::Alias(AliasTy::Projection(projection_ty.clone())).intern(Interner),
|
|
false,
|
|
));
|
|
}
|
|
predicates
|
|
})
|
|
}
|
|
|
|
fn lower_dyn_trait(&self, bounds: &[Interned<TypeBound>]) -> Ty {
|
|
let self_ty = TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0)).intern(Interner);
|
|
// INVARIANT: The principal trait bound, if present, must come first. Others may be in any
|
|
// order but should be in the same order for the same set but possibly different order of
|
|
// bounds in the input.
|
|
// INVARIANT: If this function returns `DynTy`, there should be at least one trait bound.
|
|
// These invariants are utilized by `TyExt::dyn_trait()` and chalk.
|
|
let bounds = self.with_shifted_in(DebruijnIndex::ONE, |ctx| {
|
|
let mut bounds: Vec<_> = bounds
|
|
.iter()
|
|
.flat_map(|b| ctx.lower_type_bound(b, self_ty.clone(), false))
|
|
.collect();
|
|
|
|
let mut multiple_regular_traits = false;
|
|
let mut multiple_same_projection = false;
|
|
bounds.sort_unstable_by(|lhs, rhs| {
|
|
use std::cmp::Ordering;
|
|
match (lhs.skip_binders(), rhs.skip_binders()) {
|
|
(WhereClause::Implemented(lhs), WhereClause::Implemented(rhs)) => {
|
|
let lhs_id = lhs.trait_id;
|
|
let lhs_is_auto = ctx.db.trait_data(from_chalk_trait_id(lhs_id)).is_auto;
|
|
let rhs_id = rhs.trait_id;
|
|
let rhs_is_auto = ctx.db.trait_data(from_chalk_trait_id(rhs_id)).is_auto;
|
|
|
|
if !lhs_is_auto && !rhs_is_auto {
|
|
multiple_regular_traits = true;
|
|
}
|
|
// Note that the ordering here is important; this ensures the invariant
|
|
// mentioned above.
|
|
(lhs_is_auto, lhs_id).cmp(&(rhs_is_auto, rhs_id))
|
|
}
|
|
(WhereClause::Implemented(_), _) => Ordering::Less,
|
|
(_, WhereClause::Implemented(_)) => Ordering::Greater,
|
|
(WhereClause::AliasEq(lhs), WhereClause::AliasEq(rhs)) => {
|
|
match (&lhs.alias, &rhs.alias) {
|
|
(AliasTy::Projection(lhs_proj), AliasTy::Projection(rhs_proj)) => {
|
|
// We only compare the `associated_ty_id`s. We shouldn't have
|
|
// multiple bounds for an associated type in the correct Rust code,
|
|
// and if we do, we error out.
|
|
if lhs_proj.associated_ty_id == rhs_proj.associated_ty_id {
|
|
multiple_same_projection = true;
|
|
}
|
|
lhs_proj.associated_ty_id.cmp(&rhs_proj.associated_ty_id)
|
|
}
|
|
// We don't produce `AliasTy::Opaque`s yet.
|
|
_ => unreachable!(),
|
|
}
|
|
}
|
|
// We don't produce `WhereClause::{TypeOutlives, LifetimeOutlives}` yet.
|
|
_ => unreachable!(),
|
|
}
|
|
});
|
|
|
|
if multiple_regular_traits || multiple_same_projection {
|
|
return None;
|
|
}
|
|
|
|
bounds.first().and_then(|b| b.trait_id())?;
|
|
|
|
// As multiple occurrences of the same auto traits *are* permitted, we deduplicate the
|
|
// bounds. We shouldn't have repeated elements besides auto traits at this point.
|
|
bounds.dedup();
|
|
|
|
Some(QuantifiedWhereClauses::from_iter(Interner, bounds))
|
|
});
|
|
|
|
if let Some(bounds) = bounds {
|
|
let bounds = crate::make_single_type_binders(bounds);
|
|
TyKind::Dyn(DynTy { bounds, lifetime: static_lifetime() }).intern(Interner)
|
|
} else {
|
|
// FIXME: report error
|
|
// (additional non-auto traits, associated type rebound, or no resolved trait)
|
|
TyKind::Error.intern(Interner)
|
|
}
|
|
}
|
|
|
|
fn lower_impl_trait(
|
|
&self,
|
|
bounds: &[Interned<TypeBound>],
|
|
func: FunctionId,
|
|
) -> ReturnTypeImplTrait {
|
|
cov_mark::hit!(lower_rpit);
|
|
let self_ty = TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0)).intern(Interner);
|
|
let predicates = self.with_shifted_in(DebruijnIndex::ONE, |ctx| {
|
|
let mut predicates: Vec<_> = bounds
|
|
.iter()
|
|
.flat_map(|b| ctx.lower_type_bound(b, self_ty.clone(), false))
|
|
.collect();
|
|
|
|
if !ctx.unsized_types.borrow().contains(&self_ty) {
|
|
let krate = func.krate(ctx.db.upcast());
|
|
let sized_trait = ctx
|
|
.db
|
|
.lang_item(krate, LangItem::Sized)
|
|
.and_then(|lang_item| lang_item.as_trait().map(to_chalk_trait_id));
|
|
let sized_clause = sized_trait.map(|trait_id| {
|
|
let clause = WhereClause::Implemented(TraitRef {
|
|
trait_id,
|
|
substitution: Substitution::from1(Interner, self_ty.clone()),
|
|
});
|
|
crate::wrap_empty_binders(clause)
|
|
});
|
|
predicates.extend(sized_clause);
|
|
predicates.shrink_to_fit();
|
|
}
|
|
predicates
|
|
});
|
|
ReturnTypeImplTrait { bounds: crate::make_single_type_binders(predicates) }
|
|
}
|
|
}
|
|
|
|
fn count_impl_traits(type_ref: &TypeRef) -> usize {
|
|
let mut count = 0;
|
|
type_ref.walk(&mut |type_ref| {
|
|
if matches!(type_ref, TypeRef::ImplTrait(_)) {
|
|
count += 1;
|
|
}
|
|
});
|
|
count
|
|
}
|
|
|
|
/// Build the signature of a callable item (function, struct or enum variant).
|
|
pub(crate) fn callable_item_sig(db: &dyn HirDatabase, def: CallableDefId) -> PolyFnSig {
|
|
match def {
|
|
CallableDefId::FunctionId(f) => fn_sig_for_fn(db, f),
|
|
CallableDefId::StructId(s) => fn_sig_for_struct_constructor(db, s),
|
|
CallableDefId::EnumVariantId(e) => fn_sig_for_enum_variant_constructor(db, e),
|
|
}
|
|
}
|
|
|
|
pub fn associated_type_shorthand_candidates<R>(
|
|
db: &dyn HirDatabase,
|
|
def: GenericDefId,
|
|
res: TypeNs,
|
|
mut cb: impl FnMut(&Name, TypeAliasId) -> Option<R>,
|
|
) -> Option<R> {
|
|
named_associated_type_shorthand_candidates(db, def, res, None, |name, _, id| cb(name, id))
|
|
}
|
|
|
|
fn named_associated_type_shorthand_candidates<R>(
|
|
db: &dyn HirDatabase,
|
|
// If the type parameter is defined in an impl and we're in a method, there
|
|
// might be additional where clauses to consider
|
|
def: GenericDefId,
|
|
res: TypeNs,
|
|
assoc_name: Option<Name>,
|
|
// Do NOT let `cb` touch `TraitRef` outside of `TyLoweringContext`. Its substitution contains
|
|
// free `BoundVar`s that need to be shifted and only `TyLoweringContext` knows how to do that
|
|
// properly (see `TyLoweringContext::select_associated_type()`).
|
|
mut cb: impl FnMut(&Name, &TraitRef, TypeAliasId) -> Option<R>,
|
|
) -> Option<R> {
|
|
let mut search = |t| {
|
|
all_super_trait_refs(db, t, |t| {
|
|
let data = db.trait_data(t.hir_trait_id());
|
|
|
|
for (name, assoc_id) in &data.items {
|
|
if let AssocItemId::TypeAliasId(alias) = assoc_id {
|
|
if let Some(result) = cb(name, &t, *alias) {
|
|
return Some(result);
|
|
}
|
|
}
|
|
}
|
|
None
|
|
})
|
|
};
|
|
|
|
match res {
|
|
TypeNs::SelfType(impl_id) => {
|
|
// we're _in_ the impl -- the binders get added back later. Correct,
|
|
// but it would be nice to make this more explicit
|
|
let trait_ref = db.impl_trait(impl_id)?.into_value_and_skipped_binders().0;
|
|
|
|
let impl_id_as_generic_def: GenericDefId = impl_id.into();
|
|
if impl_id_as_generic_def != def {
|
|
// `trait_ref` contains `BoundVar`s bound by impl's `Binders`, but here we need
|
|
// `BoundVar`s from `def`'s point of view.
|
|
// FIXME: A `HirDatabase` query may be handy if this process is needed in more
|
|
// places. It'd be almost identical as `impl_trait_query` where `resolver` would be
|
|
// of `def` instead of `impl_id`.
|
|
let starting_idx = generics(db.upcast(), def).len_self();
|
|
let subst = TyBuilder::subst_for_def(db, impl_id, None)
|
|
.fill_with_bound_vars(DebruijnIndex::INNERMOST, starting_idx)
|
|
.build();
|
|
let trait_ref = subst.apply(trait_ref, Interner);
|
|
search(trait_ref)
|
|
} else {
|
|
search(trait_ref)
|
|
}
|
|
}
|
|
TypeNs::GenericParam(param_id) => {
|
|
let predicates = db.generic_predicates_for_param(def, param_id.into(), assoc_name);
|
|
let res = predicates.iter().find_map(|pred| match pred.skip_binders().skip_binders() {
|
|
// FIXME: how to correctly handle higher-ranked bounds here?
|
|
WhereClause::Implemented(tr) => search(
|
|
tr.clone()
|
|
.shifted_out_to(Interner, DebruijnIndex::ONE)
|
|
.expect("FIXME unexpected higher-ranked trait bound"),
|
|
),
|
|
_ => None,
|
|
});
|
|
if res.is_some() {
|
|
return res;
|
|
}
|
|
// Handle `Self::Type` referring to own associated type in trait definitions
|
|
if let GenericDefId::TraitId(trait_id) = param_id.parent() {
|
|
let trait_generics = generics(db.upcast(), trait_id.into());
|
|
if trait_generics.params.type_or_consts[param_id.local_id()].is_trait_self() {
|
|
let def_generics = generics(db.upcast(), def);
|
|
let starting_idx = match def {
|
|
GenericDefId::TraitId(_) => 0,
|
|
// `def` is an item within trait. We need to substitute `BoundVar`s but
|
|
// remember that they are for parent (i.e. trait) generic params so they
|
|
// come after our own params.
|
|
_ => def_generics.len_self(),
|
|
};
|
|
let trait_ref = TyBuilder::trait_ref(db, trait_id)
|
|
.fill_with_bound_vars(DebruijnIndex::INNERMOST, starting_idx)
|
|
.build();
|
|
return search(trait_ref);
|
|
}
|
|
}
|
|
None
|
|
}
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
/// Build the type of all specific fields of a struct or enum variant.
|
|
pub(crate) fn field_types_query(
|
|
db: &dyn HirDatabase,
|
|
variant_id: VariantId,
|
|
) -> Arc<ArenaMap<LocalFieldId, Binders<Ty>>> {
|
|
let var_data = variant_id.variant_data(db.upcast());
|
|
let (resolver, def): (_, GenericDefId) = match variant_id {
|
|
VariantId::StructId(it) => (it.resolver(db.upcast()), it.into()),
|
|
VariantId::UnionId(it) => (it.resolver(db.upcast()), it.into()),
|
|
VariantId::EnumVariantId(it) => {
|
|
(it.resolver(db.upcast()), it.lookup(db.upcast()).parent.into())
|
|
}
|
|
};
|
|
let generics = generics(db.upcast(), def);
|
|
let mut res = ArenaMap::default();
|
|
let ctx = TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
for (field_id, field_data) in var_data.fields().iter() {
|
|
res.insert(field_id, make_binders(db, &generics, ctx.lower_ty(&field_data.type_ref)));
|
|
}
|
|
Arc::new(res)
|
|
}
|
|
|
|
/// This query exists only to be used when resolving short-hand associated types
|
|
/// like `T::Item`.
|
|
///
|
|
/// See the analogous query in rustc and its comment:
|
|
/// <https://github.com/rust-lang/rust/blob/9150f844e2624eb013ec78ca08c1d416e6644026/src/librustc_typeck/astconv.rs#L46>
|
|
/// This is a query mostly to handle cycles somewhat gracefully; e.g. the
|
|
/// following bounds are disallowed: `T: Foo<U::Item>, U: Foo<T::Item>`, but
|
|
/// these are fine: `T: Foo<U::Item>, U: Foo<()>`.
|
|
pub(crate) fn generic_predicates_for_param_query(
|
|
db: &dyn HirDatabase,
|
|
def: GenericDefId,
|
|
param_id: TypeOrConstParamId,
|
|
assoc_name: Option<Name>,
|
|
) -> Arc<[Binders<QuantifiedWhereClause>]> {
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx = if let GenericDefId::FunctionId(_) = def {
|
|
TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_impl_trait_mode(ImplTraitLoweringMode::Variable)
|
|
.with_type_param_mode(ParamLoweringMode::Variable)
|
|
} else {
|
|
TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable)
|
|
};
|
|
let generics = generics(db.upcast(), def);
|
|
|
|
// we have to filter out all other predicates *first*, before attempting to lower them
|
|
let predicate = |pred: &&_| match pred {
|
|
WherePredicate::ForLifetime { target, bound, .. }
|
|
| WherePredicate::TypeBound { target, bound, .. } => {
|
|
let invalid_target = match target {
|
|
WherePredicateTypeTarget::TypeRef(type_ref) => {
|
|
ctx.lower_ty_only_param(type_ref) != Some(param_id)
|
|
}
|
|
&WherePredicateTypeTarget::TypeOrConstParam(local_id) => {
|
|
let target_id = TypeOrConstParamId { parent: def, local_id };
|
|
target_id != param_id
|
|
}
|
|
};
|
|
if invalid_target {
|
|
return false;
|
|
}
|
|
|
|
match &**bound {
|
|
TypeBound::ForLifetime(_, path) | TypeBound::Path(path, _) => {
|
|
// Only lower the bound if the trait could possibly define the associated
|
|
// type we're looking for.
|
|
|
|
let Some(assoc_name) = &assoc_name else { return true };
|
|
let Some(TypeNs::TraitId(tr)) =
|
|
resolver.resolve_path_in_type_ns_fully(db.upcast(), path)
|
|
else {
|
|
return false;
|
|
};
|
|
|
|
all_super_traits(db.upcast(), tr).iter().any(|tr| {
|
|
db.trait_data(*tr).items.iter().any(|(name, item)| {
|
|
matches!(item, AssocItemId::TypeAliasId(_)) && name == assoc_name
|
|
})
|
|
})
|
|
}
|
|
TypeBound::Lifetime(_) | TypeBound::Error => false,
|
|
}
|
|
}
|
|
WherePredicate::Lifetime { .. } => false,
|
|
};
|
|
let mut predicates: Vec<_> = resolver
|
|
.where_predicates_in_scope()
|
|
.filter(predicate)
|
|
.flat_map(|pred| {
|
|
ctx.lower_where_predicate(pred, true).map(|p| make_binders(db, &generics, p))
|
|
})
|
|
.collect();
|
|
|
|
let subst = generics.bound_vars_subst(db, DebruijnIndex::INNERMOST);
|
|
let explicitly_unsized_tys = ctx.unsized_types.into_inner();
|
|
let implicitly_sized_predicates =
|
|
implicitly_sized_clauses(db, param_id.parent, &explicitly_unsized_tys, &subst, &resolver)
|
|
.map(|p| make_binders(db, &generics, crate::wrap_empty_binders(p)));
|
|
predicates.extend(implicitly_sized_predicates);
|
|
predicates.into()
|
|
}
|
|
|
|
pub(crate) fn generic_predicates_for_param_recover(
|
|
_db: &dyn HirDatabase,
|
|
_cycle: &Cycle,
|
|
_def: &GenericDefId,
|
|
_param_id: &TypeOrConstParamId,
|
|
_assoc_name: &Option<Name>,
|
|
) -> Arc<[Binders<QuantifiedWhereClause>]> {
|
|
Arc::from_iter(None)
|
|
}
|
|
|
|
pub(crate) fn trait_environment_for_body_query(
|
|
db: &dyn HirDatabase,
|
|
def: DefWithBodyId,
|
|
) -> Arc<TraitEnvironment> {
|
|
let Some(def) = def.as_generic_def_id() else {
|
|
let krate = def.module(db.upcast()).krate();
|
|
return TraitEnvironment::empty(krate);
|
|
};
|
|
db.trait_environment(def)
|
|
}
|
|
|
|
pub(crate) fn trait_environment_query(
|
|
db: &dyn HirDatabase,
|
|
def: GenericDefId,
|
|
) -> Arc<TraitEnvironment> {
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx = if let GenericDefId::FunctionId(_) = def {
|
|
TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_impl_trait_mode(ImplTraitLoweringMode::Param)
|
|
.with_type_param_mode(ParamLoweringMode::Placeholder)
|
|
} else {
|
|
TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_type_param_mode(ParamLoweringMode::Placeholder)
|
|
};
|
|
let mut traits_in_scope = Vec::new();
|
|
let mut clauses = Vec::new();
|
|
for pred in resolver.where_predicates_in_scope() {
|
|
for pred in ctx.lower_where_predicate(pred, false) {
|
|
if let WhereClause::Implemented(tr) = &pred.skip_binders() {
|
|
traits_in_scope.push((tr.self_type_parameter(Interner).clone(), tr.hir_trait_id()));
|
|
}
|
|
let program_clause: chalk_ir::ProgramClause<Interner> = pred.cast(Interner);
|
|
clauses.push(program_clause.into_from_env_clause(Interner));
|
|
}
|
|
}
|
|
|
|
let container: Option<ItemContainerId> = match def {
|
|
// FIXME: is there a function for this?
|
|
GenericDefId::FunctionId(f) => Some(f.lookup(db.upcast()).container),
|
|
GenericDefId::AdtId(_) => None,
|
|
GenericDefId::TraitId(_) => None,
|
|
GenericDefId::TraitAliasId(_) => None,
|
|
GenericDefId::TypeAliasId(t) => Some(t.lookup(db.upcast()).container),
|
|
GenericDefId::ImplId(_) => None,
|
|
GenericDefId::EnumVariantId(_) => None,
|
|
GenericDefId::ConstId(c) => Some(c.lookup(db.upcast()).container),
|
|
};
|
|
if let Some(ItemContainerId::TraitId(trait_id)) = container {
|
|
// add `Self: Trait<T1, T2, ...>` to the environment in trait
|
|
// function default implementations (and speculative code
|
|
// inside consts or type aliases)
|
|
cov_mark::hit!(trait_self_implements_self);
|
|
let substs = TyBuilder::placeholder_subst(db, trait_id);
|
|
let trait_ref = TraitRef { trait_id: to_chalk_trait_id(trait_id), substitution: substs };
|
|
let pred = WhereClause::Implemented(trait_ref);
|
|
let program_clause: chalk_ir::ProgramClause<Interner> = pred.cast(Interner);
|
|
clauses.push(program_clause.into_from_env_clause(Interner));
|
|
}
|
|
|
|
let subst = generics(db.upcast(), def).placeholder_subst(db);
|
|
let explicitly_unsized_tys = ctx.unsized_types.into_inner();
|
|
let implicitly_sized_clauses =
|
|
implicitly_sized_clauses(db, def, &explicitly_unsized_tys, &subst, &resolver).map(|pred| {
|
|
let program_clause: chalk_ir::ProgramClause<Interner> = pred.cast(Interner);
|
|
program_clause.into_from_env_clause(Interner)
|
|
});
|
|
clauses.extend(implicitly_sized_clauses);
|
|
|
|
let krate = def.module(db.upcast()).krate();
|
|
|
|
let env = chalk_ir::Environment::new(Interner).add_clauses(Interner, clauses);
|
|
|
|
TraitEnvironment::new(krate, None, traits_in_scope.into_boxed_slice(), env)
|
|
}
|
|
|
|
/// Resolve the where clause(s) of an item with generics.
|
|
pub(crate) fn generic_predicates_query(
|
|
db: &dyn HirDatabase,
|
|
def: GenericDefId,
|
|
) -> Arc<[Binders<QuantifiedWhereClause>]> {
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx = if let GenericDefId::FunctionId(_) = def {
|
|
TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_impl_trait_mode(ImplTraitLoweringMode::Variable)
|
|
.with_type_param_mode(ParamLoweringMode::Variable)
|
|
} else {
|
|
TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable)
|
|
};
|
|
let generics = generics(db.upcast(), def);
|
|
|
|
let mut predicates = resolver
|
|
.where_predicates_in_scope()
|
|
.flat_map(|pred| {
|
|
ctx.lower_where_predicate(pred, false).map(|p| make_binders(db, &generics, p))
|
|
})
|
|
.collect::<Vec<_>>();
|
|
|
|
let subst = generics.bound_vars_subst(db, DebruijnIndex::INNERMOST);
|
|
let explicitly_unsized_tys = ctx.unsized_types.into_inner();
|
|
let implicitly_sized_predicates =
|
|
implicitly_sized_clauses(db, def, &explicitly_unsized_tys, &subst, &resolver)
|
|
.map(|p| make_binders(db, &generics, crate::wrap_empty_binders(p)));
|
|
predicates.extend(implicitly_sized_predicates);
|
|
predicates.into()
|
|
}
|
|
|
|
/// Generate implicit `: Sized` predicates for all generics that has no `?Sized` bound.
|
|
/// Exception is Self of a trait def.
|
|
fn implicitly_sized_clauses<'a>(
|
|
db: &dyn HirDatabase,
|
|
def: GenericDefId,
|
|
explicitly_unsized_tys: &'a FxHashSet<Ty>,
|
|
substitution: &'a Substitution,
|
|
resolver: &Resolver,
|
|
) -> impl Iterator<Item = WhereClause> + 'a {
|
|
let is_trait_def = matches!(def, GenericDefId::TraitId(..));
|
|
let generic_args = &substitution.as_slice(Interner)[is_trait_def as usize..];
|
|
let sized_trait = db
|
|
.lang_item(resolver.krate(), LangItem::Sized)
|
|
.and_then(|lang_item| lang_item.as_trait().map(to_chalk_trait_id));
|
|
|
|
sized_trait.into_iter().flat_map(move |sized_trait| {
|
|
let implicitly_sized_tys = generic_args
|
|
.iter()
|
|
.filter_map(|generic_arg| generic_arg.ty(Interner))
|
|
.filter(move |&self_ty| !explicitly_unsized_tys.contains(self_ty));
|
|
implicitly_sized_tys.map(move |self_ty| {
|
|
WhereClause::Implemented(TraitRef {
|
|
trait_id: sized_trait,
|
|
substitution: Substitution::from1(Interner, self_ty.clone()),
|
|
})
|
|
})
|
|
})
|
|
}
|
|
|
|
/// Resolve the default type params from generics
|
|
pub(crate) fn generic_defaults_query(
|
|
db: &dyn HirDatabase,
|
|
def: GenericDefId,
|
|
) -> Arc<[Binders<crate::GenericArg>]> {
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx = TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
let generic_params = generics(db.upcast(), def);
|
|
let parent_start_idx = generic_params.len_self();
|
|
|
|
let defaults = Arc::from_iter(generic_params.iter().enumerate().map(|(idx, (id, p))| {
|
|
match p {
|
|
TypeOrConstParamData::TypeParamData(p) => {
|
|
let mut ty =
|
|
p.default.as_ref().map_or(TyKind::Error.intern(Interner), |t| ctx.lower_ty(t));
|
|
// Each default can only refer to previous parameters.
|
|
// Type variable default referring to parameter coming
|
|
// after it is forbidden (FIXME: report diagnostic)
|
|
ty = fallback_bound_vars(ty, idx, parent_start_idx);
|
|
crate::make_binders(db, &generic_params, ty.cast(Interner))
|
|
}
|
|
TypeOrConstParamData::ConstParamData(p) => {
|
|
let mut val = p.default.as_ref().map_or_else(
|
|
|| {
|
|
unknown_const_as_generic(
|
|
db.const_param_ty(ConstParamId::from_unchecked(id)),
|
|
)
|
|
},
|
|
|c| {
|
|
let c = ctx.lower_const(c, ctx.lower_ty(&p.ty));
|
|
c.cast(Interner)
|
|
},
|
|
);
|
|
// Each default can only refer to previous parameters, see above.
|
|
val = fallback_bound_vars(val, idx, parent_start_idx);
|
|
make_binders(db, &generic_params, val)
|
|
}
|
|
}
|
|
}));
|
|
|
|
defaults
|
|
}
|
|
|
|
pub(crate) fn generic_defaults_recover(
|
|
db: &dyn HirDatabase,
|
|
_cycle: &Cycle,
|
|
def: &GenericDefId,
|
|
) -> Arc<[Binders<crate::GenericArg>]> {
|
|
let generic_params = generics(db.upcast(), *def);
|
|
// FIXME: this code is not covered in tests.
|
|
// we still need one default per parameter
|
|
let defaults = Arc::from_iter(generic_params.iter_id().map(|id| {
|
|
let val = match id {
|
|
Either::Left(_) => TyKind::Error.intern(Interner).cast(Interner),
|
|
Either::Right(id) => unknown_const_as_generic(db.const_param_ty(id)),
|
|
};
|
|
crate::make_binders(db, &generic_params, val)
|
|
}));
|
|
|
|
defaults
|
|
}
|
|
|
|
fn fn_sig_for_fn(db: &dyn HirDatabase, def: FunctionId) -> PolyFnSig {
|
|
let data = db.function_data(def);
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx_params = TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_impl_trait_mode(ImplTraitLoweringMode::Variable)
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
let params = data.params.iter().map(|tr| ctx_params.lower_ty(tr)).collect::<Vec<_>>();
|
|
let ctx_ret = TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_impl_trait_mode(ImplTraitLoweringMode::Opaque)
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
let ret = ctx_ret.lower_ty(&data.ret_type);
|
|
let generics = generics(db.upcast(), def.into());
|
|
let sig = CallableSig::from_params_and_return(
|
|
params,
|
|
ret,
|
|
data.is_varargs(),
|
|
if data.has_unsafe_kw() { Safety::Unsafe } else { Safety::Safe },
|
|
data.abi.as_deref().map_or(FnAbi::Rust, FnAbi::from_str),
|
|
);
|
|
make_binders(db, &generics, sig)
|
|
}
|
|
|
|
/// Build the declared type of a function. This should not need to look at the
|
|
/// function body.
|
|
fn type_for_fn(db: &dyn HirDatabase, def: FunctionId) -> Binders<Ty> {
|
|
let generics = generics(db.upcast(), def.into());
|
|
let substs = generics.bound_vars_subst(db, DebruijnIndex::INNERMOST);
|
|
make_binders(
|
|
db,
|
|
&generics,
|
|
TyKind::FnDef(CallableDefId::FunctionId(def).to_chalk(db), substs).intern(Interner),
|
|
)
|
|
}
|
|
|
|
/// Build the declared type of a const.
|
|
fn type_for_const(db: &dyn HirDatabase, def: ConstId) -> Binders<Ty> {
|
|
let data = db.const_data(def);
|
|
let generics = generics(db.upcast(), def.into());
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx = TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
|
|
make_binders(db, &generics, ctx.lower_ty(&data.type_ref))
|
|
}
|
|
|
|
/// Build the declared type of a static.
|
|
fn type_for_static(db: &dyn HirDatabase, def: StaticId) -> Binders<Ty> {
|
|
let data = db.static_data(def);
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx = TyLoweringContext::new(db, &resolver, def.into());
|
|
|
|
Binders::empty(Interner, ctx.lower_ty(&data.type_ref))
|
|
}
|
|
|
|
fn fn_sig_for_struct_constructor(db: &dyn HirDatabase, def: StructId) -> PolyFnSig {
|
|
let struct_data = db.struct_data(def);
|
|
let fields = struct_data.variant_data.fields();
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx = TyLoweringContext::new(db, &resolver, AdtId::from(def).into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
let params = fields.iter().map(|(_, field)| ctx.lower_ty(&field.type_ref)).collect::<Vec<_>>();
|
|
let (ret, binders) = type_for_adt(db, def.into()).into_value_and_skipped_binders();
|
|
Binders::new(
|
|
binders,
|
|
CallableSig::from_params_and_return(params, ret, false, Safety::Safe, FnAbi::RustCall),
|
|
)
|
|
}
|
|
|
|
/// Build the type of a tuple struct constructor.
|
|
fn type_for_struct_constructor(db: &dyn HirDatabase, def: StructId) -> Option<Binders<Ty>> {
|
|
let struct_data = db.struct_data(def);
|
|
match struct_data.variant_data.kind() {
|
|
StructKind::Record => None,
|
|
StructKind::Unit => Some(type_for_adt(db, def.into())),
|
|
StructKind::Tuple => {
|
|
let generics = generics(db.upcast(), AdtId::from(def).into());
|
|
let substs = generics.bound_vars_subst(db, DebruijnIndex::INNERMOST);
|
|
Some(make_binders(
|
|
db,
|
|
&generics,
|
|
TyKind::FnDef(CallableDefId::StructId(def).to_chalk(db), substs).intern(Interner),
|
|
))
|
|
}
|
|
}
|
|
}
|
|
|
|
fn fn_sig_for_enum_variant_constructor(db: &dyn HirDatabase, def: EnumVariantId) -> PolyFnSig {
|
|
let var_data = db.enum_variant_data(def);
|
|
let fields = var_data.variant_data.fields();
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx = TyLoweringContext::new(db, &resolver, DefWithBodyId::VariantId(def).into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
let params = fields.iter().map(|(_, field)| ctx.lower_ty(&field.type_ref)).collect::<Vec<_>>();
|
|
let (ret, binders) =
|
|
type_for_adt(db, def.lookup(db.upcast()).parent.into()).into_value_and_skipped_binders();
|
|
Binders::new(
|
|
binders,
|
|
CallableSig::from_params_and_return(params, ret, false, Safety::Safe, FnAbi::RustCall),
|
|
)
|
|
}
|
|
|
|
/// Build the type of a tuple enum variant constructor.
|
|
fn type_for_enum_variant_constructor(
|
|
db: &dyn HirDatabase,
|
|
def: EnumVariantId,
|
|
) -> Option<Binders<Ty>> {
|
|
let e = def.lookup(db.upcast()).parent;
|
|
match db.enum_variant_data(def).variant_data.kind() {
|
|
StructKind::Record => None,
|
|
StructKind::Unit => Some(type_for_adt(db, e.into())),
|
|
StructKind::Tuple => {
|
|
let generics = generics(db.upcast(), e.into());
|
|
let substs = generics.bound_vars_subst(db, DebruijnIndex::INNERMOST);
|
|
Some(make_binders(
|
|
db,
|
|
&generics,
|
|
TyKind::FnDef(CallableDefId::EnumVariantId(def).to_chalk(db), substs)
|
|
.intern(Interner),
|
|
))
|
|
}
|
|
}
|
|
}
|
|
|
|
fn type_for_adt(db: &dyn HirDatabase, adt: AdtId) -> Binders<Ty> {
|
|
let generics = generics(db.upcast(), adt.into());
|
|
let subst = generics.bound_vars_subst(db, DebruijnIndex::INNERMOST);
|
|
let ty = TyKind::Adt(crate::AdtId(adt), subst).intern(Interner);
|
|
make_binders(db, &generics, ty)
|
|
}
|
|
|
|
fn type_for_type_alias(db: &dyn HirDatabase, t: TypeAliasId) -> Binders<Ty> {
|
|
let generics = generics(db.upcast(), t.into());
|
|
let resolver = t.resolver(db.upcast());
|
|
let ctx = TyLoweringContext::new(db, &resolver, t.into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
let type_alias_data = db.type_alias_data(t);
|
|
if type_alias_data.is_extern {
|
|
Binders::empty(Interner, TyKind::Foreign(crate::to_foreign_def_id(t)).intern(Interner))
|
|
} else {
|
|
let type_ref = &type_alias_data.type_ref;
|
|
let inner = ctx.lower_ty(type_ref.as_deref().unwrap_or(&TypeRef::Error));
|
|
make_binders(db, &generics, inner)
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
|
|
pub enum CallableDefId {
|
|
FunctionId(FunctionId),
|
|
StructId(StructId),
|
|
EnumVariantId(EnumVariantId),
|
|
}
|
|
impl_intern_value_trivial!(CallableDefId);
|
|
impl_from!(FunctionId, StructId, EnumVariantId for CallableDefId);
|
|
impl From<CallableDefId> for ModuleDefId {
|
|
fn from(def: CallableDefId) -> ModuleDefId {
|
|
match def {
|
|
CallableDefId::FunctionId(f) => ModuleDefId::FunctionId(f),
|
|
CallableDefId::StructId(s) => ModuleDefId::AdtId(AdtId::StructId(s)),
|
|
CallableDefId::EnumVariantId(e) => ModuleDefId::EnumVariantId(e),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl CallableDefId {
|
|
pub fn krate(self, db: &dyn HirDatabase) -> CrateId {
|
|
let db = db.upcast();
|
|
match self {
|
|
CallableDefId::FunctionId(f) => f.krate(db),
|
|
CallableDefId::StructId(s) => s.krate(db),
|
|
CallableDefId::EnumVariantId(e) => e.krate(db),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl From<CallableDefId> for GenericDefId {
|
|
fn from(def: CallableDefId) -> GenericDefId {
|
|
match def {
|
|
CallableDefId::FunctionId(f) => f.into(),
|
|
CallableDefId::StructId(s) => s.into(),
|
|
CallableDefId::EnumVariantId(e) => e.into(),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
|
|
pub enum TyDefId {
|
|
BuiltinType(BuiltinType),
|
|
AdtId(AdtId),
|
|
TypeAliasId(TypeAliasId),
|
|
}
|
|
impl_from!(BuiltinType, AdtId(StructId, EnumId, UnionId), TypeAliasId for TyDefId);
|
|
|
|
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
|
|
pub enum ValueTyDefId {
|
|
FunctionId(FunctionId),
|
|
StructId(StructId),
|
|
UnionId(UnionId),
|
|
EnumVariantId(EnumVariantId),
|
|
ConstId(ConstId),
|
|
StaticId(StaticId),
|
|
}
|
|
impl_from!(FunctionId, StructId, UnionId, EnumVariantId, ConstId, StaticId for ValueTyDefId);
|
|
|
|
impl ValueTyDefId {
|
|
pub(crate) fn to_generic_def_id(self) -> Option<GenericDefId> {
|
|
match self {
|
|
Self::FunctionId(id) => Some(id.into()),
|
|
Self::StructId(id) => Some(id.into()),
|
|
Self::UnionId(id) => Some(id.into()),
|
|
Self::EnumVariantId(var) => Some(var.into()),
|
|
Self::ConstId(id) => Some(id.into()),
|
|
Self::StaticId(_) => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Build the declared type of an item. This depends on the namespace; e.g. for
|
|
/// `struct Foo(usize)`, we have two types: The type of the struct itself, and
|
|
/// the constructor function `(usize) -> Foo` which lives in the values
|
|
/// namespace.
|
|
pub(crate) fn ty_query(db: &dyn HirDatabase, def: TyDefId) -> Binders<Ty> {
|
|
match def {
|
|
TyDefId::BuiltinType(it) => Binders::empty(Interner, TyBuilder::builtin(it)),
|
|
TyDefId::AdtId(it) => type_for_adt(db, it),
|
|
TyDefId::TypeAliasId(it) => type_for_type_alias(db, it),
|
|
}
|
|
}
|
|
|
|
pub(crate) fn ty_recover(db: &dyn HirDatabase, _cycle: &Cycle, def: &TyDefId) -> Binders<Ty> {
|
|
let generics = match *def {
|
|
TyDefId::BuiltinType(_) => return Binders::empty(Interner, TyKind::Error.intern(Interner)),
|
|
TyDefId::AdtId(it) => generics(db.upcast(), it.into()),
|
|
TyDefId::TypeAliasId(it) => generics(db.upcast(), it.into()),
|
|
};
|
|
make_binders(db, &generics, TyKind::Error.intern(Interner))
|
|
}
|
|
|
|
pub(crate) fn value_ty_query(db: &dyn HirDatabase, def: ValueTyDefId) -> Option<Binders<Ty>> {
|
|
match def {
|
|
ValueTyDefId::FunctionId(it) => Some(type_for_fn(db, it)),
|
|
ValueTyDefId::StructId(it) => type_for_struct_constructor(db, it),
|
|
ValueTyDefId::UnionId(it) => Some(type_for_adt(db, it.into())),
|
|
ValueTyDefId::EnumVariantId(it) => type_for_enum_variant_constructor(db, it),
|
|
ValueTyDefId::ConstId(it) => Some(type_for_const(db, it)),
|
|
ValueTyDefId::StaticId(it) => Some(type_for_static(db, it)),
|
|
}
|
|
}
|
|
|
|
pub(crate) fn impl_self_ty_query(db: &dyn HirDatabase, impl_id: ImplId) -> Binders<Ty> {
|
|
let impl_data = db.impl_data(impl_id);
|
|
let resolver = impl_id.resolver(db.upcast());
|
|
let generics = generics(db.upcast(), impl_id.into());
|
|
let ctx = TyLoweringContext::new(db, &resolver, impl_id.into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
make_binders(db, &generics, ctx.lower_ty(&impl_data.self_ty))
|
|
}
|
|
|
|
// returns None if def is a type arg
|
|
pub(crate) fn const_param_ty_query(db: &dyn HirDatabase, def: ConstParamId) -> Ty {
|
|
let parent_data = db.generic_params(def.parent());
|
|
let data = &parent_data.type_or_consts[def.local_id()];
|
|
let resolver = def.parent().resolver(db.upcast());
|
|
let ctx = TyLoweringContext::new(db, &resolver, def.parent().into());
|
|
match data {
|
|
TypeOrConstParamData::TypeParamData(_) => {
|
|
never!();
|
|
Ty::new(Interner, TyKind::Error)
|
|
}
|
|
TypeOrConstParamData::ConstParamData(d) => ctx.lower_ty(&d.ty),
|
|
}
|
|
}
|
|
|
|
pub(crate) fn impl_self_ty_recover(
|
|
db: &dyn HirDatabase,
|
|
_cycle: &Cycle,
|
|
impl_id: &ImplId,
|
|
) -> Binders<Ty> {
|
|
let generics = generics(db.upcast(), (*impl_id).into());
|
|
make_binders(db, &generics, TyKind::Error.intern(Interner))
|
|
}
|
|
|
|
pub(crate) fn impl_trait_query(db: &dyn HirDatabase, impl_id: ImplId) -> Option<Binders<TraitRef>> {
|
|
let impl_data = db.impl_data(impl_id);
|
|
let resolver = impl_id.resolver(db.upcast());
|
|
let ctx = TyLoweringContext::new(db, &resolver, impl_id.into())
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
let (self_ty, binders) = db.impl_self_ty(impl_id).into_value_and_skipped_binders();
|
|
let target_trait = impl_data.target_trait.as_ref()?;
|
|
Some(Binders::new(binders, ctx.lower_trait_ref(target_trait, Some(self_ty))?))
|
|
}
|
|
|
|
pub(crate) fn return_type_impl_traits(
|
|
db: &dyn HirDatabase,
|
|
def: hir_def::FunctionId,
|
|
) -> Option<Arc<Binders<ReturnTypeImplTraits>>> {
|
|
// FIXME unify with fn_sig_for_fn instead of doing lowering twice, maybe
|
|
let data = db.function_data(def);
|
|
let resolver = def.resolver(db.upcast());
|
|
let ctx_ret = TyLoweringContext::new(db, &resolver, def.into())
|
|
.with_impl_trait_mode(ImplTraitLoweringMode::Opaque)
|
|
.with_type_param_mode(ParamLoweringMode::Variable);
|
|
let _ret = ctx_ret.lower_ty(&data.ret_type);
|
|
let generics = generics(db.upcast(), def.into());
|
|
let return_type_impl_traits = ReturnTypeImplTraits {
|
|
impl_traits: match ctx_ret.impl_trait_mode {
|
|
ImplTraitLoweringState::Opaque(x) => x.into_inner(),
|
|
_ => unreachable!(),
|
|
},
|
|
};
|
|
if return_type_impl_traits.impl_traits.is_empty() {
|
|
None
|
|
} else {
|
|
Some(Arc::new(make_binders(db, &generics, return_type_impl_traits)))
|
|
}
|
|
}
|
|
|
|
pub(crate) fn lower_to_chalk_mutability(m: hir_def::type_ref::Mutability) -> Mutability {
|
|
match m {
|
|
hir_def::type_ref::Mutability::Shared => Mutability::Not,
|
|
hir_def::type_ref::Mutability::Mut => Mutability::Mut,
|
|
}
|
|
}
|
|
|
|
/// Checks if the provided generic arg matches its expected kind, then lower them via
|
|
/// provided closures. Use unknown if there was kind mismatch.
|
|
///
|
|
/// Returns `Some` of the lowered generic arg. `None` if the provided arg is a lifetime.
|
|
pub(crate) fn generic_arg_to_chalk<'a, T>(
|
|
db: &dyn HirDatabase,
|
|
kind_id: Either<TypeParamId, ConstParamId>,
|
|
arg: &'a GenericArg,
|
|
this: &mut T,
|
|
for_type: impl FnOnce(&mut T, &TypeRef) -> Ty + 'a,
|
|
for_const: impl FnOnce(&mut T, &ConstRef, Ty) -> Const + 'a,
|
|
) -> Option<crate::GenericArg> {
|
|
let kind = match kind_id {
|
|
Either::Left(_) => ParamKind::Type,
|
|
Either::Right(id) => {
|
|
let ty = db.const_param_ty(id);
|
|
ParamKind::Const(ty)
|
|
}
|
|
};
|
|
Some(match (arg, kind) {
|
|
(GenericArg::Type(type_ref), ParamKind::Type) => for_type(this, type_ref).cast(Interner),
|
|
(GenericArg::Const(c), ParamKind::Const(c_ty)) => for_const(this, c, c_ty).cast(Interner),
|
|
(GenericArg::Const(_), ParamKind::Type) => TyKind::Error.intern(Interner).cast(Interner),
|
|
(GenericArg::Type(t), ParamKind::Const(c_ty)) => {
|
|
// We want to recover simple idents, which parser detects them
|
|
// as types. Maybe here is not the best place to do it, but
|
|
// it works.
|
|
if let TypeRef::Path(p) = t {
|
|
let p = p.mod_path()?;
|
|
if p.kind == PathKind::Plain {
|
|
if let [n] = p.segments() {
|
|
let c = ConstRef::Path(n.clone());
|
|
return Some(for_const(this, &c, c_ty).cast(Interner));
|
|
}
|
|
}
|
|
}
|
|
unknown_const_as_generic(c_ty)
|
|
}
|
|
(GenericArg::Lifetime(_), _) => return None,
|
|
})
|
|
}
|
|
|
|
pub(crate) fn const_or_path_to_chalk(
|
|
db: &dyn HirDatabase,
|
|
resolver: &Resolver,
|
|
owner: TypeOwnerId,
|
|
expected_ty: Ty,
|
|
value: &ConstRef,
|
|
mode: ParamLoweringMode,
|
|
args: impl FnOnce() -> Generics,
|
|
debruijn: DebruijnIndex,
|
|
) -> Const {
|
|
match value {
|
|
ConstRef::Scalar(s) => intern_const_ref(db, s, expected_ty, resolver.krate()),
|
|
ConstRef::Path(n) => {
|
|
let path = ModPath::from_segments(PathKind::Plain, Some(n.clone()));
|
|
path_to_const(
|
|
db,
|
|
resolver,
|
|
&Path::from_known_path_with_no_generic(path),
|
|
mode,
|
|
args,
|
|
debruijn,
|
|
expected_ty.clone(),
|
|
)
|
|
.unwrap_or_else(|| unknown_const(expected_ty))
|
|
}
|
|
&ConstRef::Complex(it) => {
|
|
let crate_data = &db.crate_graph()[owner.module(db.upcast()).krate()];
|
|
if crate_data.env.get("__ra_is_test_fixture").is_none() && crate_data.origin.is_local()
|
|
{
|
|
// FIXME: current `InTypeConstId` is very unstable, so we only use it in non local crate
|
|
// that are unlikely to be edited.
|
|
return unknown_const(expected_ty);
|
|
}
|
|
let c = db
|
|
.intern_in_type_const(InTypeConstLoc {
|
|
id: it,
|
|
owner,
|
|
expected_ty: Box::new(InTypeConstIdMetadata(expected_ty.clone())),
|
|
})
|
|
.into();
|
|
intern_const_scalar(
|
|
ConstScalar::UnevaluatedConst(c, Substitution::empty(Interner)),
|
|
expected_ty,
|
|
)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Replaces any 'free' `BoundVar`s in `s` by `TyKind::Error` from the perspective of generic
|
|
/// parameter whose index is `param_index`. A `BoundVar` is free when it is or (syntactically)
|
|
/// appears after the generic parameter of `param_index`.
|
|
fn fallback_bound_vars<T: TypeFoldable<Interner> + HasInterner<Interner = Interner>>(
|
|
s: T,
|
|
param_index: usize,
|
|
parent_start: usize,
|
|
) -> T {
|
|
// Keep in mind that parent generic parameters, if any, come *after* those of the item in
|
|
// question. In the diagrams below, `c*` and `p*` represent generic parameters of the item and
|
|
// its parent respectively.
|
|
let is_allowed = |index| {
|
|
if param_index < parent_start {
|
|
// The parameter of `param_index` is one from the item in question. Any parent generic
|
|
// parameters or the item's generic parameters that come before `param_index` is
|
|
// allowed.
|
|
// [c1, .., cj, .., ck, p1, .., pl] where cj is `param_index`
|
|
// ^^^^^^ ^^^^^^^^^^ these are allowed
|
|
!(param_index..parent_start).contains(&index)
|
|
} else {
|
|
// The parameter of `param_index` is one from the parent generics. Only parent generic
|
|
// parameters that come before `param_index` are allowed.
|
|
// [c1, .., ck, p1, .., pj, .., pl] where pj is `param_index`
|
|
// ^^^^^^ these are allowed
|
|
(parent_start..param_index).contains(&index)
|
|
}
|
|
};
|
|
|
|
crate::fold_free_vars(
|
|
s,
|
|
|bound, binders| {
|
|
if bound.index_if_innermost().map_or(true, is_allowed) {
|
|
bound.shifted_in_from(binders).to_ty(Interner)
|
|
} else {
|
|
TyKind::Error.intern(Interner)
|
|
}
|
|
},
|
|
|ty, bound, binders| {
|
|
if bound.index_if_innermost().map_or(true, is_allowed) {
|
|
bound.shifted_in_from(binders).to_const(Interner, ty)
|
|
} else {
|
|
unknown_const(ty)
|
|
}
|
|
},
|
|
)
|
|
}
|