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)*) };
27 pub mod method_resolution;
39 fold::{Shift, TypeFoldable},
40 interner::HasInterner,
43 use hir_def::{expr::ExprId, type_ref::Rawness, TypeOrConstParamId};
44 use itertools::Either;
47 use crate::{consteval::unknown_const, db::HirDatabase, utils::generics};
49 pub use autoderef::autoderef;
50 pub use builder::{ParamKind, TyBuilder};
53 could_coerce, could_unify, Adjust, Adjustment, AutoBorrow, BindingMode, InferenceDiagnostic,
56 pub use interner::Interner;
58 associated_type_shorthand_candidates, CallableDefId, ImplTraitLoweringMode, TyDefId,
59 TyLoweringContext, ValueTyDefId,
62 from_assoc_type_id, from_chalk_trait_id, from_foreign_def_id, from_placeholder_idx,
63 lt_from_placeholder_idx, to_assoc_type_id, to_chalk_trait_id, to_foreign_def_id,
66 pub use traits::TraitEnvironment;
67 pub use utils::{all_super_traits, is_fn_unsafe_to_call};
68 pub use walk::TypeWalk;
71 cast::Cast, AdtId, BoundVar, DebruijnIndex, Mutability, Safety, Scalar, TyVariableKind,
74 pub type ForeignDefId = chalk_ir::ForeignDefId<Interner>;
75 pub type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
76 pub type FnDefId = chalk_ir::FnDefId<Interner>;
77 pub type ClosureId = chalk_ir::ClosureId<Interner>;
78 pub type OpaqueTyId = chalk_ir::OpaqueTyId<Interner>;
79 pub type PlaceholderIndex = chalk_ir::PlaceholderIndex;
81 pub type VariableKind = chalk_ir::VariableKind<Interner>;
82 pub type VariableKinds = chalk_ir::VariableKinds<Interner>;
83 pub type CanonicalVarKinds = chalk_ir::CanonicalVarKinds<Interner>;
84 pub type Binders<T> = chalk_ir::Binders<T>;
85 pub type Substitution = chalk_ir::Substitution<Interner>;
86 pub type GenericArg = chalk_ir::GenericArg<Interner>;
87 pub type GenericArgData = chalk_ir::GenericArgData<Interner>;
89 pub type Ty = chalk_ir::Ty<Interner>;
90 pub type TyKind = chalk_ir::TyKind<Interner>;
91 pub type DynTy = chalk_ir::DynTy<Interner>;
92 pub type FnPointer = chalk_ir::FnPointer<Interner>;
93 // pub type FnSubst = chalk_ir::FnSubst<Interner>;
94 pub use chalk_ir::FnSubst;
95 pub type ProjectionTy = chalk_ir::ProjectionTy<Interner>;
96 pub type AliasTy = chalk_ir::AliasTy<Interner>;
97 pub type OpaqueTy = chalk_ir::OpaqueTy<Interner>;
98 pub type InferenceVar = chalk_ir::InferenceVar;
100 pub type Lifetime = chalk_ir::Lifetime<Interner>;
101 pub type LifetimeData = chalk_ir::LifetimeData<Interner>;
102 pub type LifetimeOutlives = chalk_ir::LifetimeOutlives<Interner>;
104 pub type Const = chalk_ir::Const<Interner>;
105 pub type ConstData = chalk_ir::ConstData<Interner>;
106 pub type ConstValue = chalk_ir::ConstValue<Interner>;
107 pub type ConcreteConst = chalk_ir::ConcreteConst<Interner>;
109 pub type ChalkTraitId = chalk_ir::TraitId<Interner>;
110 pub type TraitRef = chalk_ir::TraitRef<Interner>;
111 pub type QuantifiedWhereClause = Binders<WhereClause>;
112 pub type QuantifiedWhereClauses = chalk_ir::QuantifiedWhereClauses<Interner>;
113 pub type Canonical<T> = chalk_ir::Canonical<T>;
115 pub type FnSig = chalk_ir::FnSig<Interner>;
117 pub type InEnvironment<T> = chalk_ir::InEnvironment<T>;
118 pub type Environment = chalk_ir::Environment<Interner>;
119 pub type DomainGoal = chalk_ir::DomainGoal<Interner>;
120 pub type Goal = chalk_ir::Goal<Interner>;
121 pub type AliasEq = chalk_ir::AliasEq<Interner>;
122 pub type Solution = chalk_solve::Solution<Interner>;
123 pub type ConstrainedSubst = chalk_ir::ConstrainedSubst<Interner>;
124 pub type Guidance = chalk_solve::Guidance<Interner>;
125 pub type WhereClause = chalk_ir::WhereClause<Interner>;
127 // FIXME: get rid of this
128 pub fn subst_prefix(s: &Substitution, n: usize) -> Substitution {
129 Substitution::from_iter(
131 s.as_slice(Interner)[..std::cmp::min(s.len(Interner), n)].iter().cloned(),
135 /// Return an index of a parameter in the generic type parameter list by it's id.
136 pub fn param_idx(db: &dyn HirDatabase, id: TypeOrConstParamId) -> Option<usize> {
137 generics(db.upcast(), id.parent).param_idx(id)
140 pub(crate) fn wrap_empty_binders<T>(value: T) -> Binders<T>
142 T: TypeFoldable<Interner> + HasInterner<Interner = Interner>,
144 Binders::empty(Interner, value.shifted_in_from(Interner, DebruijnIndex::ONE))
147 pub(crate) fn make_type_and_const_binders<T: HasInterner<Interner = Interner>>(
148 which_is_const: impl Iterator<Item = Option<Ty>>,
152 VariableKinds::from_iter(
154 which_is_const.map(|x| {
155 if let Some(ty) = x {
156 chalk_ir::VariableKind::Const(ty)
158 chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General)
166 pub(crate) fn make_single_type_binders<T: HasInterner<Interner = Interner>>(
170 VariableKinds::from_iter(
172 std::iter::once(chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General)),
178 pub(crate) fn make_binders_with_count<T: HasInterner<Interner = Interner>>(
179 db: &dyn HirDatabase,
184 let it = generics.iter_id().take(count).map(|id| match id {
185 Either::Left(_) => None,
186 Either::Right(id) => Some(db.const_param_ty(id)),
188 crate::make_type_and_const_binders(it, value)
191 pub(crate) fn make_binders<T: HasInterner<Interner = Interner>>(
192 db: &dyn HirDatabase,
196 make_binders_with_count(db, usize::MAX, generics, value)
199 // FIXME: get rid of this, just replace it by FnPointer
200 /// A function signature as seen by type inference: Several parameter types and
202 #[derive(Clone, PartialEq, Eq, Debug)]
203 pub struct CallableSig {
204 params_and_return: Arc<[Ty]>,
208 has_interner!(CallableSig);
210 /// A polymorphic function signature.
211 pub type PolyFnSig = Binders<CallableSig>;
214 pub fn from_params_and_return(mut params: Vec<Ty>, ret: Ty, is_varargs: bool) -> CallableSig {
216 CallableSig { params_and_return: params.into(), is_varargs }
219 pub fn from_fn_ptr(fn_ptr: &FnPointer) -> CallableSig {
221 // FIXME: what to do about lifetime params? -> return PolyFnSig
222 params_and_return: fn_ptr
225 .shifted_out_to(Interner, DebruijnIndex::ONE)
226 .expect("unexpected lifetime vars in fn ptr")
230 .map(|arg| arg.assert_ty_ref(Interner).clone())
232 is_varargs: fn_ptr.sig.variadic,
236 pub fn to_fn_ptr(&self) -> FnPointer {
239 sig: FnSig { abi: (), safety: Safety::Safe, variadic: self.is_varargs },
240 substitution: FnSubst(Substitution::from_iter(
242 self.params_and_return.iter().cloned(),
247 pub fn params(&self) -> &[Ty] {
248 &self.params_and_return[0..self.params_and_return.len() - 1]
251 pub fn ret(&self) -> &Ty {
252 &self.params_and_return[self.params_and_return.len() - 1]
256 impl TypeFoldable<Interner> for CallableSig {
259 folder: &mut dyn chalk_ir::fold::TypeFolder<Interner, Error = E>,
260 outer_binder: DebruijnIndex,
261 ) -> Result<Self, E> {
262 let vec = self.params_and_return.to_vec();
263 let folded = vec.fold_with(folder, outer_binder)?;
264 Ok(CallableSig { params_and_return: folded.into(), is_varargs: self.is_varargs })
268 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
269 pub enum ImplTraitId {
270 ReturnTypeImplTrait(hir_def::FunctionId, u16),
271 AsyncBlockTypeImplTrait(hir_def::DefWithBodyId, ExprId),
274 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
275 pub struct ReturnTypeImplTraits {
276 pub(crate) impl_traits: Vec<ReturnTypeImplTrait>,
279 has_interner!(ReturnTypeImplTraits);
281 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
282 pub(crate) struct ReturnTypeImplTrait {
283 pub(crate) bounds: Binders<Vec<QuantifiedWhereClause>>,
286 pub fn static_lifetime() -> Lifetime {
287 LifetimeData::Static.intern(Interner)
290 pub(crate) fn fold_free_vars<T: HasInterner<Interner = Interner> + TypeFoldable<Interner>>(
292 for_ty: impl FnMut(BoundVar, DebruijnIndex) -> Ty,
293 for_const: impl FnMut(Ty, BoundVar, DebruijnIndex) -> Const,
295 use chalk_ir::{fold::TypeFolder, Fallible};
296 struct FreeVarFolder<F1, F2>(F1, F2);
299 F1: FnMut(BoundVar, DebruijnIndex) -> Ty + 'i,
300 F2: FnMut(Ty, BoundVar, DebruijnIndex) -> Const + 'i,
301 > TypeFolder<Interner> for FreeVarFolder<F1, F2>
303 type Error = NoSolution;
305 fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner, Error = Self::Error> {
309 fn interner(&self) -> Interner {
316 outer_binder: DebruijnIndex,
318 Ok(self.0(bound_var, outer_binder))
321 fn fold_free_var_const(
325 outer_binder: DebruijnIndex,
326 ) -> Fallible<Const> {
327 Ok(self.1(ty, bound_var, outer_binder))
330 t.fold_with(&mut FreeVarFolder(for_ty, for_const), DebruijnIndex::INNERMOST)
331 .expect("fold failed unexpectedly")
334 pub(crate) fn fold_tys<T: HasInterner<Interner = Interner> + TypeFoldable<Interner>>(
336 mut for_ty: impl FnMut(Ty, DebruijnIndex) -> Ty,
337 binders: DebruijnIndex,
342 Either::Left(x) => Either::Left(for_ty(x, d)),
343 Either::Right(x) => Either::Right(x),
349 pub(crate) fn fold_tys_and_consts<T: HasInterner<Interner = Interner> + TypeFoldable<Interner>>(
351 f: impl FnMut(Either<Ty, Const>, DebruijnIndex) -> Either<Ty, Const>,
352 binders: DebruijnIndex,
355 fold::{TypeFolder, TypeSuperFoldable},
358 struct TyFolder<F>(F);
359 impl<'i, F: FnMut(Either<Ty, Const>, DebruijnIndex) -> Either<Ty, Const> + 'i>
360 TypeFolder<Interner> for TyFolder<F>
362 type Error = NoSolution;
364 fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner, Error = Self::Error> {
368 fn interner(&self) -> Interner {
372 fn fold_ty(&mut self, ty: Ty, outer_binder: DebruijnIndex) -> Fallible<Ty> {
373 let ty = ty.super_fold_with(self.as_dyn(), outer_binder)?;
374 Ok(self.0(Either::Left(ty), outer_binder).left().unwrap())
377 fn fold_const(&mut self, c: Const, outer_binder: DebruijnIndex) -> Fallible<Const> {
378 Ok(self.0(Either::Right(c), outer_binder).right().unwrap())
381 t.fold_with(&mut TyFolder(f), binders).expect("fold failed unexpectedly")
384 /// 'Canonicalizes' the `t` by replacing any errors with new variables. Also
385 /// ensures there are no unbound variables or inference variables anywhere in
387 pub fn replace_errors_with_variables<T>(t: &T) -> Canonical<T>
389 T: HasInterner<Interner = Interner> + TypeFoldable<Interner> + Clone,
390 T: HasInterner<Interner = Interner>,
393 fold::{TypeFolder, TypeSuperFoldable},
396 struct ErrorReplacer {
399 impl TypeFolder<Interner> for ErrorReplacer {
400 type Error = NoSolution;
402 fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner, Error = Self::Error> {
406 fn interner(&self) -> Interner {
410 fn fold_ty(&mut self, ty: Ty, outer_binder: DebruijnIndex) -> Fallible<Ty> {
411 if let TyKind::Error = ty.kind(Interner) {
412 let index = self.vars;
414 Ok(TyKind::BoundVar(BoundVar::new(outer_binder, index)).intern(Interner))
416 let ty = ty.super_fold_with(self.as_dyn(), outer_binder)?;
421 fn fold_inference_ty(
424 _kind: TyVariableKind,
425 _outer_binder: DebruijnIndex,
427 if cfg!(debug_assertions) {
428 // we don't want to just panic here, because then the error message
429 // won't contain the whole thing, which would not be very helpful
432 Ok(TyKind::Error.intern(Interner))
438 _bound_var: BoundVar,
439 _outer_binder: DebruijnIndex,
441 if cfg!(debug_assertions) {
442 // we don't want to just panic here, because then the error message
443 // won't contain the whole thing, which would not be very helpful
446 Ok(TyKind::Error.intern(Interner))
450 fn fold_inference_const(
454 _outer_binder: DebruijnIndex,
455 ) -> Fallible<Const> {
456 if cfg!(debug_assertions) {
459 Ok(unknown_const(ty))
463 fn fold_free_var_const(
466 _bound_var: BoundVar,
467 _outer_binder: DebruijnIndex,
468 ) -> Fallible<Const> {
469 if cfg!(debug_assertions) {
472 Ok(unknown_const(ty))
476 fn fold_inference_lifetime(
479 _outer_binder: DebruijnIndex,
480 ) -> Fallible<Lifetime> {
481 if cfg!(debug_assertions) {
484 Ok(static_lifetime())
488 fn fold_free_var_lifetime(
490 _bound_var: BoundVar,
491 _outer_binder: DebruijnIndex,
492 ) -> Fallible<Lifetime> {
493 if cfg!(debug_assertions) {
496 Ok(static_lifetime())
500 let mut error_replacer = ErrorReplacer { vars: 0 };
501 let value = match t.clone().fold_with(&mut error_replacer, DebruijnIndex::INNERMOST) {
503 Err(_) => panic!("Encountered unbound or inference vars in {:?}", t),
505 let kinds = (0..error_replacer.vars).map(|_| {
506 chalk_ir::CanonicalVarKind::new(
507 chalk_ir::VariableKind::Ty(TyVariableKind::General),
508 chalk_ir::UniverseIndex::ROOT,
511 Canonical { value, binders: chalk_ir::CanonicalVarKinds::from_iter(Interner, kinds) }