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|
//! 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, ChalkRustDefId as RustDefId};
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::ParameterKind::Ty(chalk_ir::UniverseIndex {
counter: ui.index(),
})
}
CanonicalTyVarKind::Int | CanonicalTyVarKind::Float => {
// FIXME(chalk) - this is actually really important
// These variable kinds put some limits on the
// types that can be substituted (floats or ints).
// While it's unclear exactly the design here, we
// probably want some way to "register" these.
chalk_ir::ParameterKind::Ty(chalk_ir::UniverseIndex::root())
}
},
CanonicalVarKind::Region(ui) => {
chalk_ir::ParameterKind::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::ParameterKind::Ty(_t) => {
use chalk_ir::TyData;
use rustc_ast::ast;
let _data = _t.data(&interner);
let kind = match _data {
TyData::Apply(_application_ty) => match _application_ty.name {
chalk_ir::TypeName::Struct(_struct_id) => match _struct_id.0 {
RustDefId::Array => unimplemented!(),
RustDefId::Slice => unimplemented!(),
_ => 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::Tuple(_size) => 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::ParameterKind::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);
}
}
});
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
assert!(_subst.value.constraints.is_empty());
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)
}
|
