1 //! The type system. We currently use this to infer types for completion, hover
2 //! information and various assists.
4 macro_rules! eprintln {
5 ($($tt:tt)*) => { stdx::eprintln!($($tt)*) };
11 pub mod method_resolution;
33 use itertools::Itertools;
37 expr::ExprId, type_ref::Rawness, AssocContainerId, FunctionId, GenericDefId, HasModule,
38 LifetimeParamId, Lookup, TraitId, TypeAliasId, TypeParamId,
41 use crate::{db::HirDatabase, display::HirDisplay, utils::generics};
43 pub use autoderef::autoderef;
44 pub use builder::TyBuilder;
45 pub use chalk_ext::{ProjectionTyExt, TyExt};
46 pub use infer::{could_unify, InferenceResult, InferenceVar};
48 associated_type_shorthand_candidates, callable_item_sig, CallableDefId, ImplTraitLoweringMode,
49 TyDefId, TyLoweringContext, ValueTyDefId,
51 pub use traits::{chalk::Interner, TraitEnvironment};
53 pub use walk::TypeWalk;
56 cast::Cast, AdtId, BoundVar, DebruijnIndex, Mutability, Safety, Scalar, TyVariableKind,
59 pub type ForeignDefId = chalk_ir::ForeignDefId<Interner>;
60 pub type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
61 pub type FnDefId = chalk_ir::FnDefId<Interner>;
62 pub type ClosureId = chalk_ir::ClosureId<Interner>;
63 pub type OpaqueTyId = chalk_ir::OpaqueTyId<Interner>;
64 pub type PlaceholderIndex = chalk_ir::PlaceholderIndex;
66 pub type VariableKind = chalk_ir::VariableKind<Interner>;
67 pub type VariableKinds = chalk_ir::VariableKinds<Interner>;
68 pub type CanonicalVarKinds = chalk_ir::CanonicalVarKinds<Interner>;
70 pub type Lifetime = chalk_ir::Lifetime<Interner>;
71 pub type LifetimeData = chalk_ir::LifetimeData<Interner>;
72 pub type LifetimeOutlives = chalk_ir::LifetimeOutlives<Interner>;
74 pub type ChalkTraitId = chalk_ir::TraitId<Interner>;
76 pub type FnSig = chalk_ir::FnSig<Interner>;
78 // FIXME: get rid of this
79 pub fn subst_prefix(s: &Substitution, n: usize) -> Substitution {
80 Substitution::intern(s.interned()[..std::cmp::min(s.len(&Interner), n)].into())
83 /// Return an index of a parameter in the generic type parameter list by it's id.
84 pub fn param_idx(db: &dyn HirDatabase, id: TypeParamId) -> Option<usize> {
85 generics(db.upcast(), id.parent).param_idx(id)
88 pub fn wrap_empty_binders<T>(value: T) -> Binders<T>
92 Binders::empty(&Interner, value.shifted_in_from(DebruijnIndex::ONE))
95 pub fn make_only_type_binders<T>(num_vars: usize, value: T) -> Binders<T> {
97 VariableKinds::from_iter(
99 std::iter::repeat(chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General))
107 pub fn hir_trait_id(&self) -> TraitId {
108 from_chalk_trait_id(self.trait_id)
112 impl<T> Canonical<T> {
113 pub fn new(value: T, kinds: impl IntoIterator<Item = TyVariableKind>) -> Self {
114 let kinds = kinds.into_iter().map(|tk| {
115 chalk_ir::CanonicalVarKind::new(
116 chalk_ir::VariableKind::Ty(tk),
117 chalk_ir::UniverseIndex::ROOT,
120 Self { value, binders: chalk_ir::CanonicalVarKinds::from_iter(&Interner, kinds) }
124 /// A function signature as seen by type inference: Several parameter types and
126 #[derive(Clone, PartialEq, Eq, Debug)]
127 pub struct CallableSig {
128 params_and_return: Arc<[Ty]>,
132 /// A polymorphic function signature.
133 pub type PolyFnSig = Binders<CallableSig>;
136 pub fn from_params_and_return(mut params: Vec<Ty>, ret: Ty, is_varargs: bool) -> CallableSig {
138 CallableSig { params_and_return: params.into(), is_varargs }
141 pub fn from_fn_ptr(fn_ptr: &FnPointer) -> CallableSig {
143 // FIXME: what to do about lifetime params? -> return PolyFnSig
144 params_and_return: fn_ptr
147 .shifted_out_to(DebruijnIndex::ONE)
148 .expect("unexpected lifetime vars in fn ptr")
151 .map(|arg| arg.assert_ty_ref(&Interner).clone())
153 is_varargs: fn_ptr.sig.variadic,
157 pub fn params(&self) -> &[Ty] {
158 &self.params_and_return[0..self.params_and_return.len() - 1]
161 pub fn ret(&self) -> &Ty {
162 &self.params_and_return[self.params_and_return.len() - 1]
167 pub fn as_reference(&self) -> Option<(&Ty, Mutability)> {
168 match self.kind(&Interner) {
169 TyKind::Ref(mutability, ty) => Some((ty, *mutability)),
174 pub fn as_reference_or_ptr(&self) -> Option<(&Ty, Rawness, Mutability)> {
175 match self.kind(&Interner) {
176 TyKind::Ref(mutability, ty) => Some((ty, Rawness::Ref, *mutability)),
177 TyKind::Raw(mutability, ty) => Some((ty, Rawness::RawPtr, *mutability)),
182 pub fn strip_references(&self) -> &Ty {
183 let mut t: &Ty = self;
185 while let TyKind::Ref(_mutability, ty) = t.kind(&Interner) {
192 pub fn as_adt(&self) -> Option<(hir_def::AdtId, &Substitution)> {
193 match self.kind(&Interner) {
194 TyKind::Adt(AdtId(adt), parameters) => Some((*adt, parameters)),
199 pub fn as_tuple(&self) -> Option<&Substitution> {
200 match self.kind(&Interner) {
201 TyKind::Tuple(_, substs) => Some(substs),
206 pub fn as_generic_def(&self, db: &dyn HirDatabase) -> Option<GenericDefId> {
207 match *self.kind(&Interner) {
208 TyKind::Adt(AdtId(adt), ..) => Some(adt.into()),
209 TyKind::FnDef(callable, ..) => {
210 Some(db.lookup_intern_callable_def(callable.into()).into())
212 TyKind::AssociatedType(type_alias, ..) => Some(from_assoc_type_id(type_alias).into()),
213 TyKind::Foreign(type_alias, ..) => Some(from_foreign_def_id(type_alias).into()),
218 pub fn is_never(&self) -> bool {
219 matches!(self.kind(&Interner), TyKind::Never)
222 pub fn is_unknown(&self) -> bool {
223 matches!(self.kind(&Interner), TyKind::Error)
226 pub fn equals_ctor(&self, other: &Ty) -> bool {
227 match (self.kind(&Interner), other.kind(&Interner)) {
228 (TyKind::Adt(adt, ..), TyKind::Adt(adt2, ..)) => adt == adt2,
229 (TyKind::Slice(_), TyKind::Slice(_)) | (TyKind::Array(_), TyKind::Array(_)) => true,
230 (TyKind::FnDef(def_id, ..), TyKind::FnDef(def_id2, ..)) => def_id == def_id2,
231 (TyKind::OpaqueType(ty_id, ..), TyKind::OpaqueType(ty_id2, ..)) => ty_id == ty_id2,
232 (TyKind::AssociatedType(ty_id, ..), TyKind::AssociatedType(ty_id2, ..)) => {
235 (TyKind::Foreign(ty_id, ..), TyKind::Foreign(ty_id2, ..)) => ty_id == ty_id2,
236 (TyKind::Closure(id1, _), TyKind::Closure(id2, _)) => id1 == id2,
237 (TyKind::Ref(mutability, ..), TyKind::Ref(mutability2, ..))
238 | (TyKind::Raw(mutability, ..), TyKind::Raw(mutability2, ..)) => {
239 mutability == mutability2
242 TyKind::Function(FnPointer { num_args, sig, .. }),
243 TyKind::Function(FnPointer { num_args: num_args2, sig: sig2, .. }),
244 ) => num_args == num_args2 && sig == sig2,
245 (TyKind::Tuple(cardinality, _), TyKind::Tuple(cardinality2, _)) => {
246 cardinality == cardinality2
248 (TyKind::Str, TyKind::Str) | (TyKind::Never, TyKind::Never) => true,
249 (TyKind::Scalar(scalar), TyKind::Scalar(scalar2)) => scalar == scalar2,
254 /// If this is a `dyn Trait` type, this returns the `Trait` part.
255 fn dyn_trait_ref(&self) -> Option<&TraitRef> {
256 match self.kind(&Interner) {
257 TyKind::Dyn(dyn_ty) => dyn_ty.bounds.skip_binders().interned().get(0).and_then(|b| {
258 match b.skip_binders() {
259 WhereClause::Implemented(trait_ref) => Some(trait_ref),
267 /// If this is a `dyn Trait`, returns that trait.
268 pub fn dyn_trait(&self) -> Option<TraitId> {
269 self.dyn_trait_ref().map(|it| it.trait_id).map(from_chalk_trait_id)
272 fn builtin_deref(&self) -> Option<Ty> {
273 match self.kind(&Interner) {
274 TyKind::Ref(.., ty) => Some(ty.clone()),
275 TyKind::Raw(.., ty) => Some(ty.clone()),
280 pub fn callable_def(&self, db: &dyn HirDatabase) -> Option<CallableDefId> {
281 match self.kind(&Interner) {
282 &TyKind::FnDef(def, ..) => Some(db.lookup_intern_callable_def(def.into())),
287 pub fn as_fn_def(&self, db: &dyn HirDatabase) -> Option<FunctionId> {
288 if let Some(CallableDefId::FunctionId(func)) = self.callable_def(db) {
295 pub fn callable_sig(&self, db: &dyn HirDatabase) -> Option<CallableSig> {
296 match self.kind(&Interner) {
297 TyKind::Function(fn_ptr) => Some(CallableSig::from_fn_ptr(fn_ptr)),
298 TyKind::FnDef(def, parameters) => {
299 let callable_def = db.lookup_intern_callable_def((*def).into());
300 let sig = db.callable_item_signature(callable_def);
301 Some(sig.substitute(&Interner, ¶meters))
303 TyKind::Closure(.., substs) => {
304 let sig_param = substs.at(&Interner, 0).assert_ty_ref(&Interner);
305 sig_param.callable_sig(db)
311 /// Returns the type parameters of this type if it has some (i.e. is an ADT
312 /// or function); so if `self` is `Option<u32>`, this returns the `u32`.
313 pub fn substs(&self) -> Option<&Substitution> {
314 match self.kind(&Interner) {
315 TyKind::Adt(_, substs)
316 | TyKind::FnDef(_, substs)
317 | TyKind::Function(FnPointer { substs, .. })
318 | TyKind::Tuple(_, substs)
319 | TyKind::OpaqueType(_, substs)
320 | TyKind::AssociatedType(_, substs)
321 | TyKind::Closure(.., substs) => Some(substs),
326 fn substs_mut(&mut self) -> Option<&mut Substitution> {
327 match self.interned_mut() {
328 TyKind::Adt(_, substs)
329 | TyKind::FnDef(_, substs)
330 | TyKind::Function(FnPointer { substs, .. })
331 | TyKind::Tuple(_, substs)
332 | TyKind::OpaqueType(_, substs)
333 | TyKind::AssociatedType(_, substs)
334 | TyKind::Closure(.., substs) => Some(substs),
339 pub fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>> {
340 match self.kind(&Interner) {
341 TyKind::OpaqueType(opaque_ty_id, ..) => {
342 match db.lookup_intern_impl_trait_id((*opaque_ty_id).into()) {
343 ImplTraitId::AsyncBlockTypeImplTrait(def, _expr) => {
344 let krate = def.module(db.upcast()).krate();
345 if let Some(future_trait) = db
346 .lang_item(krate, "future_trait".into())
347 .and_then(|item| item.as_trait())
349 // This is only used by type walking.
350 // Parameters will be walked outside, and projection predicate is not used.
351 // So just provide the Future trait.
352 let impl_bound = Binders::empty(
354 WhereClause::Implemented(TraitRef {
355 trait_id: to_chalk_trait_id(future_trait),
356 substitution: Substitution::empty(&Interner),
359 Some(vec![impl_bound])
364 ImplTraitId::ReturnTypeImplTrait(..) => None,
367 TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
368 let predicates = match db.lookup_intern_impl_trait_id(opaque_ty.opaque_ty_id.into())
370 ImplTraitId::ReturnTypeImplTrait(func, idx) => {
371 db.return_type_impl_traits(func).map(|it| {
374 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
375 data.substitute(&Interner, &opaque_ty.substitution)
378 // It always has an parameter for Future::Output type.
379 ImplTraitId::AsyncBlockTypeImplTrait(..) => unreachable!(),
382 predicates.map(|it| it.into_value_and_skipped_binders().0)
384 TyKind::Placeholder(idx) => {
385 let id = from_placeholder_idx(db, *idx);
386 let generic_params = db.generic_params(id.parent);
387 let param_data = &generic_params.types[id.local_id];
388 match param_data.provenance {
389 hir_def::generics::TypeParamProvenance::ArgumentImplTrait => {
390 let substs = TyBuilder::type_params_subst(db, id.parent);
392 .generic_predicates(id.parent)
394 .map(|pred| pred.clone().substitute(&Interner, &substs))
395 .filter(|wc| match &wc.skip_binders() {
396 WhereClause::Implemented(tr) => {
397 tr.self_type_parameter(&Interner) == self
399 WhereClause::AliasEq(AliasEq {
400 alias: AliasTy::Projection(proj),
402 }) => proj.self_type_parameter(&Interner) == self,
416 pub fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId> {
417 match self.kind(&Interner) {
418 TyKind::AssociatedType(id, ..) => {
419 match from_assoc_type_id(*id).lookup(db.upcast()).container {
420 AssocContainerId::TraitId(trait_id) => Some(trait_id),
424 TyKind::Alias(AliasTy::Projection(projection_ty)) => {
425 match from_assoc_type_id(projection_ty.associated_ty_id)
429 AssocContainerId::TraitId(trait_id) => Some(trait_id),
438 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
439 pub enum ImplTraitId {
440 ReturnTypeImplTrait(hir_def::FunctionId, u16),
441 AsyncBlockTypeImplTrait(hir_def::DefWithBodyId, ExprId),
444 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
445 pub struct ReturnTypeImplTraits {
446 pub(crate) impl_traits: Vec<ReturnTypeImplTrait>,
449 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
450 pub(crate) struct ReturnTypeImplTrait {
451 pub(crate) bounds: Binders<Vec<QuantifiedWhereClause>>,
454 pub fn to_foreign_def_id(id: TypeAliasId) -> ForeignDefId {
455 chalk_ir::ForeignDefId(salsa::InternKey::as_intern_id(&id))
458 pub fn from_foreign_def_id(id: ForeignDefId) -> TypeAliasId {
459 salsa::InternKey::from_intern_id(id.0)
462 pub fn to_assoc_type_id(id: TypeAliasId) -> AssocTypeId {
463 chalk_ir::AssocTypeId(salsa::InternKey::as_intern_id(&id))
466 pub fn from_assoc_type_id(id: AssocTypeId) -> TypeAliasId {
467 salsa::InternKey::from_intern_id(id.0)
470 pub fn from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> TypeParamId {
471 assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
472 let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
473 db.lookup_intern_type_param_id(interned_id)
476 pub fn to_placeholder_idx(db: &dyn HirDatabase, id: TypeParamId) -> PlaceholderIndex {
477 let interned_id = db.intern_type_param_id(id);
479 ui: chalk_ir::UniverseIndex::ROOT,
480 idx: salsa::InternKey::as_intern_id(&interned_id).as_usize(),
484 pub fn lt_from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> LifetimeParamId {
485 assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
486 let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
487 db.lookup_intern_lifetime_param_id(interned_id)
490 pub fn to_chalk_trait_id(id: TraitId) -> ChalkTraitId {
491 chalk_ir::TraitId(salsa::InternKey::as_intern_id(&id))
494 pub fn from_chalk_trait_id(id: ChalkTraitId) -> TraitId {
495 salsa::InternKey::from_intern_id(id.0)