diff options
Diffstat (limited to 'compiler/rustc_traits/src/chalk/mod.rs')
| -rw-r--r-- | compiler/rustc_traits/src/chalk/mod.rs | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/compiler/rustc_traits/src/chalk/mod.rs b/compiler/rustc_traits/src/chalk/mod.rs new file mode 100644 index 00000000000..f18b4ca65f6 --- /dev/null +++ b/compiler/rustc_traits/src/chalk/mod.rs @@ -0,0 +1,229 @@ +//! Calls `chalk-solve` to solve a `ty::Predicate` +//! +//! In order to call `chalk-solve`, this file must convert a +//! `ChalkCanonicalGoal` into a Chalk ucanonical goal. It then calls Chalk, and +//! converts the answer back into rustc solution. + +crate mod db; +crate mod lowering; + +use rustc_data_structures::fx::FxHashMap; + +use rustc_index::vec::IndexVec; + +use rustc_middle::infer::canonical::{CanonicalTyVarKind, CanonicalVarKind}; +use rustc_middle::traits::ChalkRustInterner; +use rustc_middle::ty::query::Providers; +use rustc_middle::ty::subst::GenericArg; +use rustc_middle::ty::{ + self, Bound, BoundVar, ParamTy, Region, RegionKind, Ty, TyCtxt, TypeFoldable, +}; + +use rustc_infer::infer::canonical::{ + Canonical, CanonicalVarValues, Certainty, QueryRegionConstraints, QueryResponse, +}; +use rustc_infer::traits::{self, ChalkCanonicalGoal}; + +use crate::chalk::db::RustIrDatabase as ChalkRustIrDatabase; +use crate::chalk::lowering::{LowerInto, ParamsSubstitutor}; + +use chalk_solve::Solution; + +crate fn provide(p: &mut Providers) { + *p = Providers { evaluate_goal, ..*p }; +} + +crate fn evaluate_goal<'tcx>( + tcx: TyCtxt<'tcx>, + obligation: ChalkCanonicalGoal<'tcx>, +) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, traits::query::NoSolution> { + let interner = ChalkRustInterner { tcx }; + + // Chalk doesn't have a notion of `Params`, so instead we use placeholders. + let mut params_substitutor = ParamsSubstitutor::new(tcx); + let obligation = obligation.fold_with(&mut params_substitutor); + let _params: FxHashMap<usize, ParamTy> = params_substitutor.params; + let max_universe = obligation.max_universe.index(); + + let _lowered_goal: chalk_ir::UCanonical< + chalk_ir::InEnvironment<chalk_ir::Goal<ChalkRustInterner<'tcx>>>, + > = chalk_ir::UCanonical { + canonical: chalk_ir::Canonical { + binders: chalk_ir::CanonicalVarKinds::from( + &interner, + obligation.variables.iter().map(|v| match v.kind { + CanonicalVarKind::PlaceholderTy(_ty) => unimplemented!(), + CanonicalVarKind::PlaceholderRegion(_ui) => unimplemented!(), + CanonicalVarKind::Ty(ty) => match ty { + CanonicalTyVarKind::General(ui) => chalk_ir::WithKind::new( + chalk_ir::VariableKind::Ty(chalk_ir::TyKind::General), + chalk_ir::UniverseIndex { counter: ui.index() }, + ), + CanonicalTyVarKind::Int => chalk_ir::WithKind::new( + chalk_ir::VariableKind::Ty(chalk_ir::TyKind::Integer), + chalk_ir::UniverseIndex::root(), + ), + CanonicalTyVarKind::Float => chalk_ir::WithKind::new( + chalk_ir::VariableKind::Ty(chalk_ir::TyKind::Float), + chalk_ir::UniverseIndex::root(), + ), + }, + CanonicalVarKind::Region(ui) => chalk_ir::WithKind::new( + chalk_ir::VariableKind::Lifetime, + chalk_ir::UniverseIndex { counter: ui.index() }, + ), + CanonicalVarKind::Const(_ui) => unimplemented!(), + CanonicalVarKind::PlaceholderConst(_pc) => unimplemented!(), + }), + ), + value: obligation.value.lower_into(&interner), + }, + universes: max_universe + 1, + }; + + let solver_choice = chalk_solve::SolverChoice::SLG { max_size: 32, expected_answers: None }; + let mut solver = solver_choice.into_solver::<ChalkRustInterner<'tcx>>(); + + let db = ChalkRustIrDatabase { tcx, interner }; + let solution = solver.solve(&db, &_lowered_goal); + + // Ideally, the code to convert *back* to rustc types would live close to + // the code to convert *from* rustc types. Right now though, we don't + // really need this and so it's really minimal. + // Right now, we also treat a `Unique` solution the same as + // `Ambig(Definite)`. This really isn't right. + let make_solution = |_subst: chalk_ir::Substitution<_>| { + let mut var_values: IndexVec<BoundVar, GenericArg<'tcx>> = IndexVec::new(); + _subst.parameters(&interner).iter().for_each(|p| { + // FIXME(chalk): we should move this elsewhere, since this is + // essentially inverse of lowering a `GenericArg`. + let _data = p.data(&interner); + match _data { + chalk_ir::GenericArgData::Ty(_t) => { + use chalk_ir::TyData; + use rustc_ast as ast; + + let _data = _t.data(&interner); + let kind = match _data { + TyData::Apply(_application_ty) => match _application_ty.name { + chalk_ir::TypeName::Adt(_struct_id) => unimplemented!(), + chalk_ir::TypeName::Scalar(scalar) => match scalar { + chalk_ir::Scalar::Bool => ty::Bool, + chalk_ir::Scalar::Char => ty::Char, + chalk_ir::Scalar::Int(int_ty) => match int_ty { + chalk_ir::IntTy::Isize => ty::Int(ast::IntTy::Isize), + chalk_ir::IntTy::I8 => ty::Int(ast::IntTy::I8), + chalk_ir::IntTy::I16 => ty::Int(ast::IntTy::I16), + chalk_ir::IntTy::I32 => ty::Int(ast::IntTy::I32), + chalk_ir::IntTy::I64 => ty::Int(ast::IntTy::I64), + chalk_ir::IntTy::I128 => ty::Int(ast::IntTy::I128), + }, + chalk_ir::Scalar::Uint(int_ty) => match int_ty { + chalk_ir::UintTy::Usize => ty::Uint(ast::UintTy::Usize), + chalk_ir::UintTy::U8 => ty::Uint(ast::UintTy::U8), + chalk_ir::UintTy::U16 => ty::Uint(ast::UintTy::U16), + chalk_ir::UintTy::U32 => ty::Uint(ast::UintTy::U32), + chalk_ir::UintTy::U64 => ty::Uint(ast::UintTy::U64), + chalk_ir::UintTy::U128 => ty::Uint(ast::UintTy::U128), + }, + chalk_ir::Scalar::Float(float_ty) => match float_ty { + chalk_ir::FloatTy::F32 => ty::Float(ast::FloatTy::F32), + chalk_ir::FloatTy::F64 => ty::Float(ast::FloatTy::F64), + }, + }, + chalk_ir::TypeName::Array => unimplemented!(), + chalk_ir::TypeName::FnDef(_) => unimplemented!(), + chalk_ir::TypeName::Closure(_) => unimplemented!(), + chalk_ir::TypeName::Never => unimplemented!(), + chalk_ir::TypeName::Tuple(_size) => unimplemented!(), + chalk_ir::TypeName::Slice => unimplemented!(), + chalk_ir::TypeName::Raw(_) => unimplemented!(), + chalk_ir::TypeName::Ref(_) => unimplemented!(), + chalk_ir::TypeName::Str => unimplemented!(), + chalk_ir::TypeName::OpaqueType(_ty) => unimplemented!(), + chalk_ir::TypeName::AssociatedType(_assoc_ty) => unimplemented!(), + chalk_ir::TypeName::Error => unimplemented!(), + }, + TyData::Placeholder(_placeholder) => { + unimplemented!(); + } + TyData::Alias(_alias_ty) => unimplemented!(), + TyData::Function(_quantified_ty) => unimplemented!(), + TyData::BoundVar(_bound) => Bound( + ty::DebruijnIndex::from_usize(_bound.debruijn.depth() as usize), + ty::BoundTy { + var: ty::BoundVar::from_usize(_bound.index), + kind: ty::BoundTyKind::Anon, + }, + ), + TyData::InferenceVar(_, _) => unimplemented!(), + TyData::Dyn(_) => unimplemented!(), + }; + let _ty: Ty<'_> = tcx.mk_ty(kind); + let _arg: GenericArg<'_> = _ty.into(); + var_values.push(_arg); + } + chalk_ir::GenericArgData::Lifetime(_l) => { + let _data = _l.data(&interner); + let _lifetime: Region<'_> = match _data { + chalk_ir::LifetimeData::BoundVar(_var) => { + tcx.mk_region(RegionKind::ReLateBound( + rustc_middle::ty::DebruijnIndex::from_usize( + _var.debruijn.depth() as usize + ), + rustc_middle::ty::BoundRegion::BrAnon(_var.index as u32), + )) + } + chalk_ir::LifetimeData::InferenceVar(_var) => unimplemented!(), + chalk_ir::LifetimeData::Placeholder(_index) => unimplemented!(), + chalk_ir::LifetimeData::Phantom(_, _) => unimplemented!(), + }; + let _arg: GenericArg<'_> = _lifetime.into(); + var_values.push(_arg); + } + chalk_ir::GenericArgData::Const(_) => unimplemented!(), + } + }); + let sol = Canonical { + max_universe: ty::UniverseIndex::from_usize(0), + variables: obligation.variables.clone(), + value: QueryResponse { + var_values: CanonicalVarValues { var_values }, + region_constraints: QueryRegionConstraints::default(), + certainty: Certainty::Proven, + value: (), + }, + }; + &*tcx.arena.alloc(sol) + }; + solution + .map(|s| match s { + Solution::Unique(_subst) => { + // FIXME(chalk): handle constraints + make_solution(_subst.value.subst) + } + Solution::Ambig(_guidance) => { + match _guidance { + chalk_solve::Guidance::Definite(_subst) => make_solution(_subst.value), + chalk_solve::Guidance::Suggested(_) => unimplemented!(), + chalk_solve::Guidance::Unknown => { + // chalk_fulfill doesn't use the var_values here, so + // let's just ignore that + let sol = Canonical { + max_universe: ty::UniverseIndex::from_usize(0), + variables: obligation.variables.clone(), + value: QueryResponse { + var_values: CanonicalVarValues { var_values: IndexVec::new() } + .make_identity(tcx), + region_constraints: QueryRegionConstraints::default(), + certainty: Certainty::Ambiguous, + value: (), + }, + }; + &*tcx.arena.alloc(sol) + } + } + } + }) + .ok_or(traits::query::NoSolution) +} |