Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/infer/unify.rs')
| -rw-r--r-- | crates/hir-ty/src/infer/unify.rs | 458 |
1 files changed, 217 insertions, 241 deletions
diff --git a/crates/hir-ty/src/infer/unify.rs b/crates/hir-ty/src/infer/unify.rs index 1687857ae1..108cf5b1a2 100644 --- a/crates/hir-ty/src/infer/unify.rs +++ b/crates/hir-ty/src/infer/unify.rs @@ -3,47 +3,42 @@ use std::fmt; use chalk_ir::{ - CanonicalVarKind, FloatTy, IntTy, TyVariableKind, cast::Cast, fold::TypeFoldable, - interner::HasInterner, + CanonicalVarKind, TyVariableKind, cast::Cast, fold::TypeFoldable, interner::HasInterner, }; use either::Either; use hir_def::{AdtId, lang_item::LangItem}; use hir_expand::name::Name; use intern::sym; use rustc_hash::{FxHashMap, FxHashSet}; -use rustc_type_ir::inherent::Ty as _; use rustc_type_ir::{ - FloatVid, IntVid, TyVid, TypeVisitableExt, - inherent::{IntoKind, Span, Term as _}, + TyVid, TypeVisitableExt, UpcastFrom, + inherent::{IntoKind, Span, Term as _, Ty as _}, relate::{Relate, solver_relating::RelateExt}, - solve::{Certainty, GoalSource, NoSolution}, + solve::{Certainty, GoalSource}, }; use smallvec::SmallVec; use triomphe::Arc; use super::{InferResult, InferenceContext, TypeError}; -use crate::next_solver::ErrorGuaranteed; use crate::{ AliasTy, BoundVar, Canonical, Const, ConstValue, DebruijnIndex, GenericArg, GenericArgData, - Goal, GoalData, InEnvironment, InferenceVar, Interner, Lifetime, OpaqueTyId, ParamKind, - ProjectionTy, Scalar, Substitution, TraitEnvironment, TraitRef, Ty, TyBuilder, TyExt, TyKind, - VariableKind, WhereClause, + InferenceVar, Interner, Lifetime, OpaqueTyId, ProjectionTy, Substitution, TraitEnvironment, Ty, + TyExt, TyKind, VariableKind, consteval::unknown_const, db::HirDatabase, fold_generic_args, fold_tys_and_consts, - next_solver::infer::InferOk, next_solver::{ - self, ClauseKind, DbInterner, ParamEnv, Predicate, PredicateKind, SolverDefIds, Term, + self, ClauseKind, DbInterner, ErrorGuaranteed, Predicate, PredicateKind, SolverDefIds, + Term, TraitRef, fulfill::FulfillmentCtxt, infer::{ - DbInternerInferExt, InferCtxt, + DbInternerInferExt, InferCtxt, InferOk, snapshot::CombinedSnapshot, traits::{Obligation, ObligationCause}, }, inspect::{InspectConfig, InspectGoal, ProofTreeVisitor}, mapping::{ChalkToNextSolver, NextSolverToChalk}, }, - to_chalk_trait_id, traits::{ FnTrait, NextTraitSolveResult, next_trait_solve_canonical_in_ctxt, next_trait_solve_in_ctxt, }, @@ -125,7 +120,7 @@ impl<'a, 'db> ProofTreeVisitor<'db> for NestedObligationsForSelfTy<'a, 'db> { /// unresolved goal `T = U`. pub fn could_unify( db: &dyn HirDatabase, - env: Arc<TraitEnvironment>, + env: Arc<TraitEnvironment<'_>>, tys: &Canonical<(Ty, Ty)>, ) -> bool { unify(db, env, tys).is_some() @@ -137,7 +132,7 @@ pub fn could_unify( /// them. For example `Option<T>` and `Option<U>` do not unify as we cannot show that `T = U` pub fn could_unify_deeply( db: &dyn HirDatabase, - env: Arc<TraitEnvironment>, + env: Arc<TraitEnvironment<'_>>, tys: &Canonical<(Ty, Ty)>, ) -> bool { let mut table = InferenceTable::new(db, env); @@ -147,7 +142,6 @@ pub fn could_unify_deeply( let ty1_with_vars = table.normalize_associated_types_in(ty1_with_vars); let ty2_with_vars = table.normalize_associated_types_in(ty2_with_vars); table.select_obligations_where_possible(); - table.propagate_diverging_flag(); let ty1_with_vars = table.resolve_completely(ty1_with_vars); let ty2_with_vars = table.resolve_completely(ty2_with_vars); table.unify_deeply(&ty1_with_vars, &ty2_with_vars) @@ -155,7 +149,7 @@ pub fn could_unify_deeply( pub(crate) fn unify( db: &dyn HirDatabase, - env: Arc<TraitEnvironment>, + env: Arc<TraitEnvironment<'_>>, tys: &Canonical<(Ty, Ty)>, ) -> Option<Substitution> { let mut table = InferenceTable::new(db, env); @@ -174,13 +168,19 @@ pub(crate) fn unify( GenericArgData::Const(c) => c.inference_var(Interner), } == Some(iv)) }; - let fallback = |iv, kind, default, binder| match kind { - chalk_ir::VariableKind::Ty(_ty_kind) => find_var(iv) - .map_or(default, |i| BoundVar::new(binder, i).to_ty(Interner).cast(Interner)), - chalk_ir::VariableKind::Lifetime => find_var(iv) - .map_or(default, |i| BoundVar::new(binder, i).to_lifetime(Interner).cast(Interner)), - chalk_ir::VariableKind::Const(ty) => find_var(iv) - .map_or(default, |i| BoundVar::new(binder, i).to_const(Interner, ty).cast(Interner)), + let fallback = |iv, kind, binder| match kind { + chalk_ir::VariableKind::Ty(_ty_kind) => find_var(iv).map_or_else( + || TyKind::Error.intern(Interner).cast(Interner), + |i| BoundVar::new(binder, i).to_ty(Interner).cast(Interner), + ), + chalk_ir::VariableKind::Lifetime => find_var(iv).map_or_else( + || crate::error_lifetime().cast(Interner), + |i| BoundVar::new(binder, i).to_lifetime(Interner).cast(Interner), + ), + chalk_ir::VariableKind::Const(ty) => find_var(iv).map_or_else( + || crate::unknown_const(ty.clone()).cast(Interner), + |i| BoundVar::new(binder, i).to_const(Interner, ty.clone()).cast(Interner), + ), }; Some(Substitution::from_iter( Interner, @@ -216,22 +216,20 @@ bitflags::bitflags! { pub(crate) struct InferenceTable<'db> { pub(crate) db: &'db dyn HirDatabase, pub(crate) interner: DbInterner<'db>, - pub(crate) trait_env: Arc<TraitEnvironment>, - pub(crate) param_env: ParamEnv<'db>, + pub(crate) trait_env: Arc<TraitEnvironment<'db>>, pub(crate) tait_coercion_table: Option<FxHashMap<OpaqueTyId, Ty>>, pub(crate) infer_ctxt: InferCtxt<'db>, - diverging_tys: FxHashSet<Ty>, pub(super) fulfillment_cx: FulfillmentCtxt<'db>, + pub(super) diverging_type_vars: FxHashSet<crate::next_solver::Ty<'db>>, } pub(crate) struct InferenceTableSnapshot<'db> { ctxt_snapshot: CombinedSnapshot, obligations: FulfillmentCtxt<'db>, - diverging_tys: FxHashSet<Ty>, } impl<'db> InferenceTable<'db> { - pub(crate) fn new(db: &'db dyn HirDatabase, trait_env: Arc<TraitEnvironment>) -> Self { + pub(crate) fn new(db: &'db dyn HirDatabase, trait_env: Arc<TraitEnvironment<'db>>) -> Self { let interner = DbInterner::new_with(db, Some(trait_env.krate), trait_env.block); let infer_ctxt = interner.infer_ctxt().build(rustc_type_ir::TypingMode::Analysis { defining_opaque_types_and_generators: SolverDefIds::new_from_iter(interner, []), @@ -239,12 +237,11 @@ impl<'db> InferenceTable<'db> { InferenceTable { db, interner, - param_env: trait_env.env.to_nextsolver(interner), trait_env, tait_coercion_table: None, fulfillment_cx: FulfillmentCtxt::new(&infer_ctxt), infer_ctxt, - diverging_tys: FxHashSet::default(), + diverging_type_vars: FxHashSet::default(), } } @@ -327,74 +324,8 @@ impl<'db> InferenceTable<'db> { } } - /// Chalk doesn't know about the `diverging` flag, so when it unifies two - /// type variables of which one is diverging, the chosen root might not be - /// diverging and we have no way of marking it as such at that time. This - /// function goes through all type variables and make sure their root is - /// marked as diverging if necessary, so that resolving them gives the right - /// result. - pub(super) fn propagate_diverging_flag(&mut self) { - let mut new_tys = FxHashSet::default(); - for ty in self.diverging_tys.iter() { - match ty.kind(Interner) { - TyKind::InferenceVar(var, kind) => match kind { - TyVariableKind::General => { - let root = InferenceVar::from( - self.infer_ctxt.root_var(TyVid::from_u32(var.index())).as_u32(), - ); - if root.index() != var.index() { - new_tys.insert(TyKind::InferenceVar(root, *kind).intern(Interner)); - } - } - TyVariableKind::Integer => { - let root = InferenceVar::from( - self.infer_ctxt - .inner - .borrow_mut() - .int_unification_table() - .find(IntVid::from_usize(var.index() as usize)) - .as_u32(), - ); - if root.index() != var.index() { - new_tys.insert(TyKind::InferenceVar(root, *kind).intern(Interner)); - } - } - TyVariableKind::Float => { - let root = InferenceVar::from( - self.infer_ctxt - .inner - .borrow_mut() - .float_unification_table() - .find(FloatVid::from_usize(var.index() as usize)) - .as_u32(), - ); - if root.index() != var.index() { - new_tys.insert(TyKind::InferenceVar(root, *kind).intern(Interner)); - } - } - }, - _ => {} - } - } - self.diverging_tys.extend(new_tys); - } - - pub(super) fn set_diverging(&mut self, iv: InferenceVar, kind: TyVariableKind) { - self.diverging_tys.insert(TyKind::InferenceVar(iv, kind).intern(Interner)); - } - - fn fallback_value(&self, iv: InferenceVar, kind: TyVariableKind) -> Ty { - let is_diverging = - self.diverging_tys.contains(&TyKind::InferenceVar(iv, kind).intern(Interner)); - if is_diverging { - return TyKind::Never.intern(Interner); - } - match kind { - TyVariableKind::General => TyKind::Error, - TyVariableKind::Integer => TyKind::Scalar(Scalar::Int(IntTy::I32)), - TyVariableKind::Float => TyKind::Scalar(Scalar::Float(FloatTy::F64)), - } - .intern(Interner) + pub(super) fn set_diverging(&mut self, ty: crate::next_solver::Ty<'db>) { + self.diverging_type_vars.insert(ty); } pub(crate) fn canonicalize<T>(&mut self, t: T) -> rustc_type_ir::Canonical<DbInterner<'db>, T> @@ -430,7 +361,7 @@ impl<'db> InferenceTable<'db> { { let ty = self.resolve_vars_with_obligations(ty); self.infer_ctxt - .at(&ObligationCause::new(), self.param_env) + .at(&ObligationCause::new(), self.trait_env.env) .deeply_normalize(ty.clone()) .unwrap_or(ty) } @@ -535,7 +466,7 @@ impl<'db> InferenceTable<'db> { let ty = var.to_ty(Interner, kind); if diverging { - self.diverging_tys.insert(ty.clone()); + self.diverging_type_vars.insert(ty.to_nextsolver(self.interner)); } ty } @@ -579,7 +510,7 @@ impl<'db> InferenceTable<'db> { pub(crate) fn resolve_with_fallback<T>( &mut self, t: T, - fallback: &dyn Fn(InferenceVar, VariableKind, GenericArg, DebruijnIndex) -> GenericArg, + fallback: &dyn Fn(InferenceVar, VariableKind, DebruijnIndex) -> GenericArg, ) -> T where T: HasInterner<Interner = Interner> + TypeFoldable<Interner>, @@ -621,7 +552,7 @@ impl<'db> InferenceTable<'db> { fn resolve_with_fallback_inner<T>( &mut self, t: T, - fallback: &dyn Fn(InferenceVar, VariableKind, GenericArg, DebruijnIndex) -> GenericArg, + fallback: &dyn Fn(InferenceVar, VariableKind, DebruijnIndex) -> GenericArg, ) -> T where T: HasInterner<Interner = Interner> + TypeFoldable<Interner>, @@ -638,53 +569,15 @@ impl<'db> InferenceTable<'db> { T: HasInterner<Interner = Interner> + TypeFoldable<Interner> + ChalkToNextSolver<'db, U>, U: NextSolverToChalk<'db, T> + rustc_type_ir::TypeFoldable<DbInterner<'db>>, { - let t = self.resolve_with_fallback(t, &|_, _, d, _| d); - let t = self.normalize_associated_types_in(t); - // let t = self.resolve_opaque_tys_in(t); - // Resolve again, because maybe normalization inserted infer vars. - self.resolve_with_fallback(t, &|_, _, d, _| d) - } + let value = t.to_nextsolver(self.interner); + let value = self.infer_ctxt.resolve_vars_if_possible(value); - /// Apply a fallback to unresolved scalar types. Integer type variables and float type - /// variables are replaced with i32 and f64, respectively. - /// - /// This method is only intended to be called just before returning inference results (i.e. in - /// `InferenceContext::resolve_all()`). - /// - /// FIXME: This method currently doesn't apply fallback to unconstrained general type variables - /// whereas rustc replaces them with `()` or `!`. - pub(super) fn fallback_if_possible(&mut self) { - let int_fallback = TyKind::Scalar(Scalar::Int(IntTy::I32)).intern(Interner); - let float_fallback = TyKind::Scalar(Scalar::Float(FloatTy::F64)).intern(Interner); - - let int_vars = self.infer_ctxt.inner.borrow_mut().int_unification_table().len(); - for v in 0..int_vars { - let var = InferenceVar::from(v as u32).to_ty(Interner, TyVariableKind::Integer); - let maybe_resolved = self.resolve_ty_shallow(&var); - if let TyKind::InferenceVar(_, kind) = maybe_resolved.kind(Interner) { - // I don't think we can ever unify these vars with float vars, but keep this here for now - let fallback = match kind { - TyVariableKind::Integer => &int_fallback, - TyVariableKind::Float => &float_fallback, - TyVariableKind::General => unreachable!(), - }; - self.unify(&var, fallback); - } - } - let float_vars = self.infer_ctxt.inner.borrow_mut().float_unification_table().len(); - for v in 0..float_vars { - let var = InferenceVar::from(v as u32).to_ty(Interner, TyVariableKind::Float); - let maybe_resolved = self.resolve_ty_shallow(&var); - if let TyKind::InferenceVar(_, kind) = maybe_resolved.kind(Interner) { - // I don't think we can ever unify these vars with float vars, but keep this here for now - let fallback = match kind { - TyVariableKind::Integer => &int_fallback, - TyVariableKind::Float => &float_fallback, - TyVariableKind::General => unreachable!(), - }; - self.unify(&var, fallback); - } - } + let mut goals = vec![]; + let value = value.fold_with(&mut resolve_completely::Resolver::new(self, true, &mut goals)); + + // FIXME(next-solver): Handle `goals`. + + value.to_chalk(self.interner) } /// Unify two relatable values (e.g. `Ty`) and register new trait goals that arise from that. @@ -745,7 +638,7 @@ impl<'db> InferenceTable<'db> { ) -> InferResult<'db, ()> { let variance = rustc_type_ir::Variance::Invariant; let span = crate::next_solver::Span::dummy(); - match self.infer_ctxt.relate(self.param_env, lhs, variance, rhs, span) { + match self.infer_ctxt.relate(self.trait_env.env, lhs, variance, rhs, span) { Ok(goals) => Ok(crate::infer::InferOk { goals, value: () }), Err(_) => Err(TypeError), } @@ -786,7 +679,7 @@ impl<'db> InferenceTable<'db> { } pub(crate) fn structurally_resolve_type(&mut self, ty: &Ty) -> Ty { - if let TyKind::Alias(..) = ty.kind(Interner) { + if let TyKind::Alias(chalk_ir::AliasTy::Projection(..)) = ty.kind(Interner) { self.structurally_normalize_ty(ty) } else { self.resolve_vars_with_obligations(ty.to_nextsolver(self.interner)) @@ -802,7 +695,7 @@ impl<'db> InferenceTable<'db> { fn structurally_normalize_term(&mut self, term: Term<'db>) -> Term<'db> { self.infer_ctxt - .at(&ObligationCause::new(), self.param_env) + .at(&ObligationCause::new(), self.trait_env.env) .structurally_normalize_term(term, &mut self.fulfillment_cx) .unwrap_or(term) } @@ -822,7 +715,7 @@ impl<'db> InferenceTable<'db> { // in a reentrant borrow, causing an ICE. let result = self .infer_ctxt - .at(&ObligationCause::misc(), self.param_env) + .at(&ObligationCause::misc(), self.trait_env.env) .structurally_normalize_ty(ty, &mut self.fulfillment_cx); match result { Ok(normalized_ty) => normalized_ty, @@ -835,15 +728,13 @@ impl<'db> InferenceTable<'db> { pub(crate) fn snapshot(&mut self) -> InferenceTableSnapshot<'db> { let ctxt_snapshot = self.infer_ctxt.start_snapshot(); - let diverging_tys = self.diverging_tys.clone(); let obligations = self.fulfillment_cx.clone(); - InferenceTableSnapshot { ctxt_snapshot, diverging_tys, obligations } + InferenceTableSnapshot { ctxt_snapshot, obligations } } #[tracing::instrument(skip_all)] pub(crate) fn rollback_to(&mut self, snapshot: InferenceTableSnapshot<'db>) { self.infer_ctxt.rollback_to(snapshot.ctxt_snapshot); - self.diverging_tys = snapshot.diverging_tys; self.fulfillment_cx = snapshot.obligations; } @@ -877,26 +768,15 @@ impl<'db> InferenceTable<'db> { /// whether a trait *might* be implemented before deciding to 'lock in' the /// choice (during e.g. method resolution or deref). #[tracing::instrument(level = "debug", skip(self))] - pub(crate) fn try_obligation(&mut self, goal: Goal) -> NextTraitSolveResult { - let in_env = InEnvironment::new(&self.trait_env.env, goal); - let canonicalized = self.canonicalize(in_env.to_nextsolver(self.interner)); + pub(crate) fn try_obligation(&mut self, predicate: Predicate<'db>) -> NextTraitSolveResult { + let goal = next_solver::Goal { param_env: self.trait_env.env, predicate }; + let canonicalized = self.canonicalize(goal); next_trait_solve_canonical_in_ctxt(&self.infer_ctxt, canonicalized) } - #[tracing::instrument(level = "debug", skip(self))] - pub(crate) fn solve_obligation(&mut self, goal: Goal) -> Result<Certainty, NoSolution> { - let goal = InEnvironment::new(&self.trait_env.env, goal); - let goal = goal.to_nextsolver(self.interner); - let result = next_trait_solve_in_ctxt(&self.infer_ctxt, goal); - result.map(|m| m.1) - } - pub(crate) fn register_obligation(&mut self, predicate: Predicate<'db>) { - let goal = next_solver::Goal { - param_env: self.trait_env.env.to_nextsolver(self.interner), - predicate, - }; + let goal = next_solver::Goal { param_env: self.trait_env.env, predicate }; self.register_obligation_in_env(goal) } @@ -984,7 +864,7 @@ impl<'db> InferenceTable<'db> { &mut self, ty: &Ty, num_args: usize, - ) -> Option<(FnTrait, Vec<crate::next_solver::Ty<'db>>, crate::next_solver::Ty<'db>)> { + ) -> Option<(FnTrait, Vec<next_solver::Ty<'db>>, next_solver::Ty<'db>)> { for (fn_trait_name, output_assoc_name, subtraits) in [ (FnTrait::FnOnce, sym::Output, &[FnTrait::Fn, FnTrait::FnMut][..]), (FnTrait::AsyncFnMut, sym::CallRefFuture, &[FnTrait::AsyncFn]), @@ -997,42 +877,34 @@ impl<'db> InferenceTable<'db> { trait_data.associated_type_by_name(&Name::new_symbol_root(output_assoc_name))?; let mut arg_tys = Vec::with_capacity(num_args); - let arg_ty = TyBuilder::tuple(num_args) - .fill(|it| { - let arg = match it { - ParamKind::Type => self.new_type_var(), - ParamKind::Lifetime => unreachable!("Tuple with lifetime parameter"), - ParamKind::Const(_) => unreachable!("Tuple with const parameter"), - }; - arg_tys.push(arg.to_nextsolver(self.interner)); - arg.cast(Interner) + let arg_ty = next_solver::Ty::new_tup_from_iter( + self.interner, + std::iter::repeat_with(|| { + let ty = self.next_ty_var(); + arg_tys.push(ty); + ty }) - .build(); - - let b = TyBuilder::trait_ref(self.db, fn_trait); - if b.remaining() != 2 { - return None; - } - let mut trait_ref = b.push(ty.clone()).push(arg_ty).build(); - - let projection = TyBuilder::assoc_type_projection( - self.db, - output_assoc_type, - Some(trait_ref.substitution.clone()), - ) - .fill_with_unknown() - .build(); - - let goal: Goal = trait_ref.clone().cast(Interner); - if !self.try_obligation(goal.clone()).no_solution() { - self.register_obligation(goal.to_nextsolver(self.interner)); - let return_ty = - self.normalize_projection_ty(projection).to_nextsolver(self.interner); + .take(num_args), + ); + let args = [ty.to_nextsolver(self.interner), arg_ty]; + let trait_ref = crate::next_solver::TraitRef::new(self.interner, fn_trait.into(), args); + + let projection = crate::next_solver::Ty::new_alias( + self.interner, + rustc_type_ir::AliasTyKind::Projection, + crate::next_solver::AliasTy::new(self.interner, output_assoc_type.into(), args), + ); + + let pred = crate::next_solver::Predicate::upcast_from(trait_ref, self.interner); + if !self.try_obligation(pred).no_solution() { + self.register_obligation(pred); + let return_ty = self.normalize_alias_ty(projection); for &fn_x in subtraits { let fn_x_trait = fn_x.get_id(self.db, krate)?; - trait_ref.trait_id = to_chalk_trait_id(fn_x_trait); - let goal = trait_ref.clone().cast(Interner); - if !self.try_obligation(goal).no_solution() { + let trait_ref = + crate::next_solver::TraitRef::new(self.interner, fn_x_trait.into(), args); + let pred = crate::next_solver::Predicate::upcast_from(trait_ref, self.interner); + if !self.try_obligation(pred).no_solution() { return Some((fn_x, arg_tys, return_ty)); } } @@ -1171,12 +1043,11 @@ impl<'db> InferenceTable<'db> { let Some(sized) = LangItem::Sized.resolve_trait(self.db, self.trait_env.krate) else { return false; }; - let sized_pred = WhereClause::Implemented(TraitRef { - trait_id: to_chalk_trait_id(sized), - substitution: Substitution::from1(Interner, ty), - }); - let goal = GoalData::DomainGoal(chalk_ir::DomainGoal::Holds(sized_pred)).intern(Interner); - self.try_obligation(goal).certain() + let sized_pred = Predicate::upcast_from( + TraitRef::new(self.interner, sized.into(), [ty.to_nextsolver(self.interner)]), + self.interner, + ); + self.try_obligation(sized_pred).certain() } } @@ -1192,14 +1063,10 @@ impl fmt::Debug for InferenceTable<'_> { mod resolve { use super::InferenceTable; use crate::{ - ConcreteConst, Const, ConstData, ConstScalar, ConstValue, DebruijnIndex, GenericArg, - InferenceVar, Interner, Lifetime, Ty, TyVariableKind, VariableKind, - next_solver::mapping::NextSolverToChalk, - }; - use chalk_ir::{ - cast::Cast, - fold::{TypeFoldable, TypeFolder}, + Const, DebruijnIndex, GenericArg, InferenceVar, Interner, Lifetime, Ty, TyVariableKind, + VariableKind, next_solver::mapping::NextSolverToChalk, }; + use chalk_ir::fold::{TypeFoldable, TypeFolder}; use rustc_type_ir::{FloatVid, IntVid, TyVid}; #[derive(Debug, Copy, Clone, PartialEq, Eq)] @@ -1213,7 +1080,7 @@ mod resolve { pub(super) struct Resolver< 'a, 'b, - F: Fn(InferenceVar, VariableKind, GenericArg, DebruijnIndex) -> GenericArg, + F: Fn(InferenceVar, VariableKind, DebruijnIndex) -> GenericArg, > { pub(super) table: &'a mut InferenceTable<'b>, pub(super) var_stack: &'a mut Vec<(InferenceVar, VarKind)>, @@ -1221,7 +1088,7 @@ mod resolve { } impl<F> TypeFolder<Interner> for Resolver<'_, '_, F> where - F: Fn(InferenceVar, VariableKind, GenericArg, DebruijnIndex) -> GenericArg, + F: Fn(InferenceVar, VariableKind, DebruijnIndex) -> GenericArg, { fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner> { self @@ -1243,8 +1110,7 @@ mod resolve { let var = InferenceVar::from(vid.as_u32()); if self.var_stack.contains(&(var, VarKind::Ty(kind))) { // recursive type - let default = self.table.fallback_value(var, kind).cast(Interner); - return (self.fallback)(var, VariableKind::Ty(kind), default, outer_binder) + return (self.fallback)(var, VariableKind::Ty(kind), outer_binder) .assert_ty_ref(Interner) .clone(); } @@ -1256,8 +1122,7 @@ mod resolve { self.var_stack.pop(); result } else { - let default = self.table.fallback_value(var, kind).cast(Interner); - (self.fallback)(var, VariableKind::Ty(kind), default, outer_binder) + (self.fallback)(var, VariableKind::Ty(kind), outer_binder) .assert_ty_ref(Interner) .clone() } @@ -1273,8 +1138,7 @@ mod resolve { let var = InferenceVar::from(vid.as_u32()); if self.var_stack.contains(&(var, VarKind::Ty(kind))) { // recursive type - let default = self.table.fallback_value(var, kind).cast(Interner); - return (self.fallback)(var, VariableKind::Ty(kind), default, outer_binder) + return (self.fallback)(var, VariableKind::Ty(kind), outer_binder) .assert_ty_ref(Interner) .clone(); } @@ -1286,8 +1150,7 @@ mod resolve { self.var_stack.pop(); result } else { - let default = self.table.fallback_value(var, kind).cast(Interner); - (self.fallback)(var, VariableKind::Ty(kind), default, outer_binder) + (self.fallback)(var, VariableKind::Ty(kind), outer_binder) .assert_ty_ref(Interner) .clone() } @@ -1303,8 +1166,7 @@ mod resolve { let var = InferenceVar::from(vid.as_u32()); if self.var_stack.contains(&(var, VarKind::Ty(kind))) { // recursive type - let default = self.table.fallback_value(var, kind).cast(Interner); - return (self.fallback)(var, VariableKind::Ty(kind), default, outer_binder) + return (self.fallback)(var, VariableKind::Ty(kind), outer_binder) .assert_ty_ref(Interner) .clone(); } @@ -1316,8 +1178,7 @@ mod resolve { self.var_stack.pop(); result } else { - let default = self.table.fallback_value(var, kind).cast(Interner); - (self.fallback)(var, VariableKind::Ty(kind), default, outer_binder) + (self.fallback)(var, VariableKind::Ty(kind), outer_binder) .assert_ty_ref(Interner) .clone() } @@ -1336,15 +1197,9 @@ mod resolve { .infer_ctxt .root_const_var(rustc_type_ir::ConstVid::from_u32(var.index())); let var = InferenceVar::from(vid.as_u32()); - let default = ConstData { - ty: ty.clone(), - value: ConstValue::Concrete(ConcreteConst { interned: ConstScalar::Unknown }), - } - .intern(Interner) - .cast(Interner); if self.var_stack.contains(&(var, VarKind::Const)) { // recursive - return (self.fallback)(var, VariableKind::Const(ty), default, outer_binder) + return (self.fallback)(var, VariableKind::Const(ty), outer_binder) .assert_const_ref(Interner) .clone(); } @@ -1356,7 +1211,7 @@ mod resolve { self.var_stack.pop(); result } else { - (self.fallback)(var, VariableKind::Const(ty), default, outer_binder) + (self.fallback)(var, VariableKind::Const(ty), outer_binder) .assert_const_ref(Interner) .clone() } @@ -1375,3 +1230,124 @@ mod resolve { } } } + +mod resolve_completely { + use rustc_type_ir::{ + DebruijnIndex, Flags, TypeFolder, TypeSuperFoldable, + inherent::{Const as _, Ty as _}, + }; + + use crate::next_solver::Region; + use crate::{ + infer::unify::InferenceTable, + next_solver::{ + Const, DbInterner, ErrorGuaranteed, Goal, Predicate, Term, Ty, + infer::traits::ObligationCause, + normalize::deeply_normalize_with_skipped_universes_and_ambiguous_coroutine_goals, + }, + }; + + pub(super) struct Resolver<'a, 'db> { + ctx: &'a mut InferenceTable<'db>, + /// Whether we should normalize, disabled when resolving predicates. + should_normalize: bool, + nested_goals: &'a mut Vec<Goal<'db, Predicate<'db>>>, + } + + impl<'a, 'db> Resolver<'a, 'db> { + pub(super) fn new( + ctx: &'a mut InferenceTable<'db>, + should_normalize: bool, + nested_goals: &'a mut Vec<Goal<'db, Predicate<'db>>>, + ) -> Resolver<'a, 'db> { + Resolver { ctx, nested_goals, should_normalize } + } + + fn handle_term<T>( + &mut self, + value: T, + outer_exclusive_binder: impl FnOnce(T) -> DebruijnIndex, + ) -> T + where + T: Into<Term<'db>> + TypeSuperFoldable<DbInterner<'db>> + Copy, + { + let value = if self.should_normalize { + let cause = ObligationCause::new(); + let at = self.ctx.infer_ctxt.at(&cause, self.ctx.trait_env.env); + let universes = vec![None; outer_exclusive_binder(value).as_usize()]; + match deeply_normalize_with_skipped_universes_and_ambiguous_coroutine_goals( + at, value, universes, + ) { + Ok((value, goals)) => { + self.nested_goals.extend(goals); + value + } + Err(_errors) => { + // FIXME: Report the error. + value + } + } + } else { + value + }; + + value.fold_with(&mut ReplaceInferWithError { interner: self.ctx.interner }) + } + } + + impl<'cx, 'db> TypeFolder<DbInterner<'db>> for Resolver<'cx, 'db> { + fn cx(&self) -> DbInterner<'db> { + self.ctx.interner + } + + fn fold_region(&mut self, r: Region<'db>) -> Region<'db> { + if r.is_var() { Region::error(self.ctx.interner) } else { r } + } + + fn fold_ty(&mut self, ty: Ty<'db>) -> Ty<'db> { + self.handle_term(ty, |it| it.outer_exclusive_binder()) + } + + fn fold_const(&mut self, ct: Const<'db>) -> Const<'db> { + self.handle_term(ct, |it| it.outer_exclusive_binder()) + } + + fn fold_predicate(&mut self, predicate: Predicate<'db>) -> Predicate<'db> { + assert!( + !self.should_normalize, + "normalizing predicates in writeback is not generally sound" + ); + predicate.super_fold_with(self) + } + } + + struct ReplaceInferWithError<'db> { + interner: DbInterner<'db>, + } + + impl<'db> TypeFolder<DbInterner<'db>> for ReplaceInferWithError<'db> { + fn cx(&self) -> DbInterner<'db> { + self.interner + } + + fn fold_ty(&mut self, t: Ty<'db>) -> Ty<'db> { + if t.is_infer() { + Ty::new_error(self.interner, ErrorGuaranteed) + } else { + t.super_fold_with(self) + } + } + + fn fold_const(&mut self, c: Const<'db>) -> Const<'db> { + if c.is_ct_infer() { + Const::new_error(self.interner, ErrorGuaranteed) + } else { + c.super_fold_with(self) + } + } + + fn fold_region(&mut self, r: Region<'db>) -> Region<'db> { + if r.is_var() { Region::error(self.interner) } else { r } + } + } +} |