1 //! The type system. We currently use this to infer types for completion, hover
2 //! information and various assists.
4 #![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
7 macro_rules! eprintln {
8 ($($tt:tt)*) => { stdx::eprintln!($($tt)*) };
26 pub mod method_resolution;
38 fold::{Shift, TypeFoldable},
39 interner::HasInterner,
42 use hir_def::{expr::ExprId, type_ref::Rawness, TypeOrConstParamId};
43 use itertools::Either;
46 use crate::{consteval::unknown_const, db::HirDatabase, utils::generics};
48 pub use autoderef::autoderef;
49 pub use builder::{ParamKind, TyBuilder};
52 could_coerce, could_unify, Adjust, Adjustment, AutoBorrow, BindingMode, InferenceDiagnostic,
55 pub use interner::Interner;
57 associated_type_shorthand_candidates, CallableDefId, ImplTraitLoweringMode, TyDefId,
58 TyLoweringContext, ValueTyDefId,
61 from_assoc_type_id, from_chalk_trait_id, from_foreign_def_id, from_placeholder_idx,
62 lt_from_placeholder_idx, to_assoc_type_id, to_chalk_trait_id, to_foreign_def_id,
65 pub use traits::TraitEnvironment;
66 pub use utils::{all_super_traits, is_fn_unsafe_to_call};
67 pub use walk::TypeWalk;
70 cast::Cast, AdtId, BoundVar, DebruijnIndex, Mutability, Safety, Scalar, TyVariableKind,
73 pub type ForeignDefId = chalk_ir::ForeignDefId<Interner>;
74 pub type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
75 pub type FnDefId = chalk_ir::FnDefId<Interner>;
76 pub type ClosureId = chalk_ir::ClosureId<Interner>;
77 pub type OpaqueTyId = chalk_ir::OpaqueTyId<Interner>;
78 pub type PlaceholderIndex = chalk_ir::PlaceholderIndex;
80 pub type VariableKind = chalk_ir::VariableKind<Interner>;
81 pub type VariableKinds = chalk_ir::VariableKinds<Interner>;
82 pub type CanonicalVarKinds = chalk_ir::CanonicalVarKinds<Interner>;
83 pub type Binders<T> = chalk_ir::Binders<T>;
84 pub type Substitution = chalk_ir::Substitution<Interner>;
85 pub type GenericArg = chalk_ir::GenericArg<Interner>;
86 pub type GenericArgData = chalk_ir::GenericArgData<Interner>;
88 pub type Ty = chalk_ir::Ty<Interner>;
89 pub type TyKind = chalk_ir::TyKind<Interner>;
90 pub type DynTy = chalk_ir::DynTy<Interner>;
91 pub type FnPointer = chalk_ir::FnPointer<Interner>;
92 // pub type FnSubst = chalk_ir::FnSubst<Interner>;
93 pub use chalk_ir::FnSubst;
94 pub type ProjectionTy = chalk_ir::ProjectionTy<Interner>;
95 pub type AliasTy = chalk_ir::AliasTy<Interner>;
96 pub type OpaqueTy = chalk_ir::OpaqueTy<Interner>;
97 pub type InferenceVar = chalk_ir::InferenceVar;
99 pub type Lifetime = chalk_ir::Lifetime<Interner>;
100 pub type LifetimeData = chalk_ir::LifetimeData<Interner>;
101 pub type LifetimeOutlives = chalk_ir::LifetimeOutlives<Interner>;
103 pub type Const = chalk_ir::Const<Interner>;
104 pub type ConstData = chalk_ir::ConstData<Interner>;
105 pub type ConstValue = chalk_ir::ConstValue<Interner>;
106 pub type ConcreteConst = chalk_ir::ConcreteConst<Interner>;
108 pub type ChalkTraitId = chalk_ir::TraitId<Interner>;
109 pub type TraitRef = chalk_ir::TraitRef<Interner>;
110 pub type QuantifiedWhereClause = Binders<WhereClause>;
111 pub type QuantifiedWhereClauses = chalk_ir::QuantifiedWhereClauses<Interner>;
112 pub type Canonical<T> = chalk_ir::Canonical<T>;
114 pub type FnSig = chalk_ir::FnSig<Interner>;
116 pub type InEnvironment<T> = chalk_ir::InEnvironment<T>;
117 pub type Environment = chalk_ir::Environment<Interner>;
118 pub type DomainGoal = chalk_ir::DomainGoal<Interner>;
119 pub type Goal = chalk_ir::Goal<Interner>;
120 pub type AliasEq = chalk_ir::AliasEq<Interner>;
121 pub type Solution = chalk_solve::Solution<Interner>;
122 pub type ConstrainedSubst = chalk_ir::ConstrainedSubst<Interner>;
123 pub type Guidance = chalk_solve::Guidance<Interner>;
124 pub type WhereClause = chalk_ir::WhereClause<Interner>;
126 // FIXME: get rid of this
127 pub fn subst_prefix(s: &Substitution, n: usize) -> Substitution {
128 Substitution::from_iter(
130 s.as_slice(Interner)[..std::cmp::min(s.len(Interner), n)].iter().cloned(),
134 /// Return an index of a parameter in the generic type parameter list by it's id.
135 pub fn param_idx(db: &dyn HirDatabase, id: TypeOrConstParamId) -> Option<usize> {
136 generics(db.upcast(), id.parent).param_idx(id)
139 pub(crate) fn wrap_empty_binders<T>(value: T) -> Binders<T>
141 T: TypeFoldable<Interner> + HasInterner<Interner = Interner>,
143 Binders::empty(Interner, value.shifted_in_from(Interner, DebruijnIndex::ONE))
146 pub(crate) fn make_type_and_const_binders<T: HasInterner<Interner = Interner>>(
147 which_is_const: impl Iterator<Item = Option<Ty>>,
151 VariableKinds::from_iter(
153 which_is_const.map(|x| {
154 if let Some(ty) = x {
155 chalk_ir::VariableKind::Const(ty)
157 chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General)
165 pub(crate) fn make_single_type_binders<T: HasInterner<Interner = Interner>>(
169 VariableKinds::from_iter(
171 std::iter::once(chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General)),
177 pub(crate) fn make_binders_with_count<T: HasInterner<Interner = Interner>>(
178 db: &dyn HirDatabase,
183 let it = generics.iter_id().take(count).map(|id| match id {
184 Either::Left(_) => None,
185 Either::Right(id) => Some(db.const_param_ty(id)),
187 crate::make_type_and_const_binders(it, value)
190 pub(crate) fn make_binders<T: HasInterner<Interner = Interner>>(
191 db: &dyn HirDatabase,
195 make_binders_with_count(db, usize::MAX, generics, value)
198 // FIXME: get rid of this
199 pub fn make_canonical<T: HasInterner<Interner = Interner>>(
201 kinds: impl IntoIterator<Item = TyVariableKind>,
203 let kinds = kinds.into_iter().map(|tk| {
204 chalk_ir::CanonicalVarKind::new(
205 chalk_ir::VariableKind::Ty(tk),
206 chalk_ir::UniverseIndex::ROOT,
209 Canonical { value, binders: chalk_ir::CanonicalVarKinds::from_iter(Interner, kinds) }
212 // FIXME: get rid of this, just replace it by FnPointer
213 /// A function signature as seen by type inference: Several parameter types and
215 #[derive(Clone, PartialEq, Eq, Debug)]
216 pub struct CallableSig {
217 params_and_return: Arc<[Ty]>,
221 has_interner!(CallableSig);
223 /// A polymorphic function signature.
224 pub type PolyFnSig = Binders<CallableSig>;
227 pub fn from_params_and_return(mut params: Vec<Ty>, ret: Ty, is_varargs: bool) -> CallableSig {
229 CallableSig { params_and_return: params.into(), is_varargs }
232 pub fn from_fn_ptr(fn_ptr: &FnPointer) -> CallableSig {
234 // FIXME: what to do about lifetime params? -> return PolyFnSig
235 params_and_return: fn_ptr
238 .shifted_out_to(Interner, DebruijnIndex::ONE)
239 .expect("unexpected lifetime vars in fn ptr")
243 .map(|arg| arg.assert_ty_ref(Interner).clone())
245 is_varargs: fn_ptr.sig.variadic,
249 pub fn to_fn_ptr(&self) -> FnPointer {
252 sig: FnSig { abi: (), safety: Safety::Safe, variadic: self.is_varargs },
253 substitution: FnSubst(Substitution::from_iter(
255 self.params_and_return.iter().cloned(),
260 pub fn params(&self) -> &[Ty] {
261 &self.params_and_return[0..self.params_and_return.len() - 1]
264 pub fn ret(&self) -> &Ty {
265 &self.params_and_return[self.params_and_return.len() - 1]
269 impl TypeFoldable<Interner> for CallableSig {
272 folder: &mut dyn chalk_ir::fold::TypeFolder<Interner, Error = E>,
273 outer_binder: DebruijnIndex,
274 ) -> Result<Self, E> {
275 let vec = self.params_and_return.to_vec();
276 let folded = vec.fold_with(folder, outer_binder)?;
277 Ok(CallableSig { params_and_return: folded.into(), is_varargs: self.is_varargs })
281 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
282 pub enum ImplTraitId {
283 ReturnTypeImplTrait(hir_def::FunctionId, u16),
284 AsyncBlockTypeImplTrait(hir_def::DefWithBodyId, ExprId),
287 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
288 pub struct ReturnTypeImplTraits {
289 pub(crate) impl_traits: Vec<ReturnTypeImplTrait>,
292 has_interner!(ReturnTypeImplTraits);
294 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
295 pub(crate) struct ReturnTypeImplTrait {
296 pub(crate) bounds: Binders<Vec<QuantifiedWhereClause>>,
299 pub fn static_lifetime() -> Lifetime {
300 LifetimeData::Static.intern(Interner)
303 pub(crate) fn fold_free_vars<T: HasInterner<Interner = Interner> + TypeFoldable<Interner>>(
305 for_ty: impl FnMut(BoundVar, DebruijnIndex) -> Ty,
306 for_const: impl FnMut(Ty, BoundVar, DebruijnIndex) -> Const,
308 use chalk_ir::{fold::TypeFolder, Fallible};
309 struct FreeVarFolder<F1, F2>(F1, F2);
312 F1: FnMut(BoundVar, DebruijnIndex) -> Ty + 'i,
313 F2: FnMut(Ty, BoundVar, DebruijnIndex) -> Const + 'i,
314 > TypeFolder<Interner> for FreeVarFolder<F1, F2>
316 type Error = NoSolution;
318 fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner, Error = Self::Error> {
322 fn interner(&self) -> Interner {
329 outer_binder: DebruijnIndex,
331 Ok(self.0(bound_var, outer_binder))
334 fn fold_free_var_const(
338 outer_binder: DebruijnIndex,
339 ) -> Fallible<Const> {
340 Ok(self.1(ty, bound_var, outer_binder))
343 t.fold_with(&mut FreeVarFolder(for_ty, for_const), DebruijnIndex::INNERMOST)
344 .expect("fold failed unexpectedly")
347 pub(crate) fn fold_tys<T: HasInterner<Interner = Interner> + TypeFoldable<Interner>>(
349 mut for_ty: impl FnMut(Ty, DebruijnIndex) -> Ty,
350 binders: DebruijnIndex,
355 Either::Left(x) => Either::Left(for_ty(x, d)),
356 Either::Right(x) => Either::Right(x),
362 pub(crate) fn fold_tys_and_consts<T: HasInterner<Interner = Interner> + TypeFoldable<Interner>>(
364 f: impl FnMut(Either<Ty, Const>, DebruijnIndex) -> Either<Ty, Const>,
365 binders: DebruijnIndex,
368 fold::{TypeFolder, TypeSuperFoldable},
371 struct TyFolder<F>(F);
372 impl<'i, F: FnMut(Either<Ty, Const>, DebruijnIndex) -> Either<Ty, Const> + 'i>
373 TypeFolder<Interner> for TyFolder<F>
375 type Error = NoSolution;
377 fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner, Error = Self::Error> {
381 fn interner(&self) -> Interner {
385 fn fold_ty(&mut self, ty: Ty, outer_binder: DebruijnIndex) -> Fallible<Ty> {
386 let ty = ty.super_fold_with(self.as_dyn(), outer_binder)?;
387 Ok(self.0(Either::Left(ty), outer_binder).left().unwrap())
390 fn fold_const(&mut self, c: Const, outer_binder: DebruijnIndex) -> Fallible<Const> {
391 Ok(self.0(Either::Right(c), outer_binder).right().unwrap())
394 t.fold_with(&mut TyFolder(f), binders).expect("fold failed unexpectedly")
397 /// 'Canonicalizes' the `t` by replacing any errors with new variables. Also
398 /// ensures there are no unbound variables or inference variables anywhere in
400 pub fn replace_errors_with_variables<T>(t: &T) -> Canonical<T>
402 T: HasInterner<Interner = Interner> + TypeFoldable<Interner> + Clone,
403 T: HasInterner<Interner = Interner>,
406 fold::{TypeFolder, TypeSuperFoldable},
409 struct ErrorReplacer {
412 impl TypeFolder<Interner> for ErrorReplacer {
413 type Error = NoSolution;
415 fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner, Error = Self::Error> {
419 fn interner(&self) -> Interner {
423 fn fold_ty(&mut self, ty: Ty, outer_binder: DebruijnIndex) -> Fallible<Ty> {
424 if let TyKind::Error = ty.kind(Interner) {
425 let index = self.vars;
427 Ok(TyKind::BoundVar(BoundVar::new(outer_binder, index)).intern(Interner))
429 let ty = ty.super_fold_with(self.as_dyn(), outer_binder)?;
434 fn fold_inference_ty(
437 _kind: TyVariableKind,
438 _outer_binder: DebruijnIndex,
440 if cfg!(debug_assertions) {
441 // we don't want to just panic here, because then the error message
442 // won't contain the whole thing, which would not be very helpful
445 Ok(TyKind::Error.intern(Interner))
451 _bound_var: BoundVar,
452 _outer_binder: DebruijnIndex,
454 if cfg!(debug_assertions) {
455 // we don't want to just panic here, because then the error message
456 // won't contain the whole thing, which would not be very helpful
459 Ok(TyKind::Error.intern(Interner))
463 fn fold_inference_const(
467 _outer_binder: DebruijnIndex,
468 ) -> Fallible<Const> {
469 if cfg!(debug_assertions) {
472 Ok(unknown_const(ty))
476 fn fold_free_var_const(
479 _bound_var: BoundVar,
480 _outer_binder: DebruijnIndex,
481 ) -> Fallible<Const> {
482 if cfg!(debug_assertions) {
485 Ok(unknown_const(ty))
489 fn fold_inference_lifetime(
492 _outer_binder: DebruijnIndex,
493 ) -> Fallible<Lifetime> {
494 if cfg!(debug_assertions) {
497 Ok(static_lifetime())
501 fn fold_free_var_lifetime(
503 _bound_var: BoundVar,
504 _outer_binder: DebruijnIndex,
505 ) -> Fallible<Lifetime> {
506 if cfg!(debug_assertions) {
509 Ok(static_lifetime())
513 let mut error_replacer = ErrorReplacer { vars: 0 };
514 let value = match t.clone().fold_with(&mut error_replacer, DebruijnIndex::INNERMOST) {
516 Err(_) => panic!("Encountered unbound or inference vars in {:?}", t),
518 let kinds = (0..error_replacer.vars).map(|_| {
519 chalk_ir::CanonicalVarKind::new(
520 chalk_ir::VariableKind::Ty(TyVariableKind::General),
521 chalk_ir::UniverseIndex::ROOT,
524 Canonical { value, binders: chalk_ir::CanonicalVarKinds::from_iter(Interner, kinds) }