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Implement some more predicates in the new solver #107102

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Jan 22, 2023
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6 changes: 2 additions & 4 deletions compiler/rustc_trait_selection/src/solve/assembly.rs
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
//! Code shared by trait and projection goals for candidate assembly.

use super::infcx_ext::InferCtxtExt;
use super::{CanonicalResponse, Certainty, EvalCtxt, Goal, MaybeCause, QueryResult};
use super::{CanonicalResponse, Certainty, EvalCtxt, Goal, QueryResult};
use rustc_hir::def_id::DefId;
use rustc_infer::traits::query::NoSolution;
use rustc_infer::traits::util::elaborate_predicates;
Expand Down Expand Up @@ -148,9 +148,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
if goal.predicate.self_ty().is_ty_var() {
return vec![Candidate {
source: CandidateSource::BuiltinImpl,
result: self
.make_canonical_response(Certainty::Maybe(MaybeCause::Ambiguity))
.unwrap(),
result: self.make_canonical_response(Certainty::AMBIGUOUS).unwrap(),
}];
}

Expand Down
83 changes: 76 additions & 7 deletions compiler/rustc_trait_selection/src/solve/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -19,14 +19,17 @@

use std::mem;

use rustc_hir::def_id::DefId;
use rustc_infer::infer::canonical::{Canonical, CanonicalVarKind, CanonicalVarValues};
use rustc_infer::infer::canonical::{OriginalQueryValues, QueryRegionConstraints, QueryResponse};
use rustc_infer::infer::{InferCtxt, InferOk, TyCtxtInferExt};
use rustc_infer::traits::query::NoSolution;
use rustc_infer::traits::Obligation;
use rustc_middle::infer::canonical::Certainty as OldCertainty;
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_middle::ty::{RegionOutlivesPredicate, ToPredicate, TypeOutlivesPredicate};
use rustc_middle::ty::{
CoercePredicate, RegionOutlivesPredicate, SubtypePredicate, ToPredicate, TypeOutlivesPredicate,
};
use rustc_span::DUMMY_SP;

use crate::traits::ObligationCause;
Expand Down Expand Up @@ -87,6 +90,8 @@ pub enum Certainty {
}

impl Certainty {
pub const AMBIGUOUS: Certainty = Certainty::Maybe(MaybeCause::Ambiguity);

/// When proving multiple goals using **AND**, e.g. nested obligations for an impl,
/// use this function to unify the certainty of these goals
pub fn unify_and(self, other: Certainty) -> Certainty {
Expand Down Expand Up @@ -243,16 +248,28 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
ty::PredicateKind::Clause(ty::Clause::RegionOutlives(predicate)) => {
self.compute_region_outlives_goal(Goal { param_env, predicate })
}
ty::PredicateKind::Subtype(predicate) => {
self.compute_subtype_goal(Goal { param_env, predicate })
}
ty::PredicateKind::Coerce(predicate) => {
self.compute_coerce_goal(Goal { param_env, predicate })
}
ty::PredicateKind::ClosureKind(def_id, substs, kind) => self
.compute_closure_kind_goal(Goal {
param_env,
predicate: (def_id, substs, kind),
}),
ty::PredicateKind::Ambiguous => self.make_canonical_response(Certainty::AMBIGUOUS),
// FIXME: implement these predicates :)
ty::PredicateKind::WellFormed(_)
| ty::PredicateKind::ObjectSafe(_)
| ty::PredicateKind::ClosureKind(_, _, _)
| ty::PredicateKind::Subtype(_)
| ty::PredicateKind::Coerce(_)
| ty::PredicateKind::ConstEvaluatable(_)
| ty::PredicateKind::ConstEquate(_, _)
| ty::PredicateKind::TypeWellFormedFromEnv(_)
| ty::PredicateKind::Ambiguous => self.make_canonical_response(Certainty::Yes),
| ty::PredicateKind::ConstEquate(_, _) => {
self.make_canonical_response(Certainty::Yes)
}
ty::PredicateKind::TypeWellFormedFromEnv(..) => {
bug!("TypeWellFormedFromEnv is only used for Chalk")
}
}
} else {
let kind = self.infcx.replace_bound_vars_with_placeholders(kind);
Expand All @@ -275,6 +292,58 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
) -> QueryResult<'tcx> {
self.make_canonical_response(Certainty::Yes)
}

fn compute_coerce_goal(
&mut self,
goal: Goal<'tcx, CoercePredicate<'tcx>>,
) -> QueryResult<'tcx> {
self.compute_subtype_goal(Goal {
param_env: goal.param_env,
predicate: SubtypePredicate {
a_is_expected: false,
a: goal.predicate.a,
b: goal.predicate.b,
},
})
}

fn compute_subtype_goal(
&mut self,
goal: Goal<'tcx, SubtypePredicate<'tcx>>,
) -> QueryResult<'tcx> {
if goal.predicate.a.is_ty_var() && goal.predicate.b.is_ty_var() {
// FIXME: Do we want to register a subtype relation between these vars?
// That won't actually reflect in the query response, so it seems moot.
self.make_canonical_response(Certainty::AMBIGUOUS)
} else {
self.infcx.probe(|_| {
let InferOk { value: (), obligations } = self
.infcx
.at(&ObligationCause::dummy(), goal.param_env)
.sub(goal.predicate.a, goal.predicate.b)?;
self.evaluate_all_and_make_canonical_response(
obligations.into_iter().map(|pred| pred.into()).collect(),
)
})
}
}

fn compute_closure_kind_goal(
&mut self,
goal: Goal<'tcx, (DefId, ty::SubstsRef<'tcx>, ty::ClosureKind)>,
) -> QueryResult<'tcx> {
let (_, substs, expected_kind) = goal.predicate;
let found_kind = substs.as_closure().kind_ty().to_opt_closure_kind();

let Some(found_kind) = found_kind else {
return self.make_canonical_response(Certainty::AMBIGUOUS);
};
if found_kind.extends(expected_kind) {
self.make_canonical_response(Certainty::Yes)
} else {
Err(NoSolution)
}
}
}

impl<'tcx> EvalCtxt<'_, 'tcx> {
Expand Down
7 changes: 3 additions & 4 deletions compiler/rustc_trait_selection/src/solve/project_goals.rs
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ use crate::traits::{specialization_graph, translate_substs};
use super::assembly::{self, Candidate, CandidateSource};
use super::infcx_ext::InferCtxtExt;
use super::trait_goals::structural_traits;
use super::{Certainty, EvalCtxt, Goal, MaybeCause, QueryResult};
use super::{Certainty, EvalCtxt, Goal, QueryResult};
use rustc_errors::ErrorGuaranteed;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::DefId;
Expand Down Expand Up @@ -229,8 +229,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
goal.predicate.def_id(),
impl_def_id
)? else {
let certainty = Certainty::Maybe(MaybeCause::Ambiguity);
return ecx.make_canonical_response(trait_ref_certainty.unify_and(certainty));
return ecx.make_canonical_response(trait_ref_certainty.unify_and(Certainty::AMBIGUOUS));
};

if !assoc_def.item.defaultness(tcx).has_value() {
Expand Down Expand Up @@ -382,7 +381,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
.to_predicate(ecx.tcx());
Self::consider_assumption(ecx, goal, pred)
} else {
ecx.make_canonical_response(Certainty::Maybe(MaybeCause::Ambiguity))
ecx.make_canonical_response(Certainty::AMBIGUOUS)
}
}

Expand Down
6 changes: 3 additions & 3 deletions compiler/rustc_trait_selection/src/solve/trait_goals.rs
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ use std::iter;

use super::assembly::{self, Candidate, CandidateSource};
use super::infcx_ext::InferCtxtExt;
use super::{Certainty, EvalCtxt, Goal, MaybeCause, QueryResult};
use super::{Certainty, EvalCtxt, Goal, QueryResult};
use rustc_hir::def_id::DefId;
use rustc_infer::infer::InferCtxt;
use rustc_infer::traits::query::NoSolution;
Expand Down Expand Up @@ -133,7 +133,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
goal: Goal<'tcx, Self>,
) -> QueryResult<'tcx> {
if goal.predicate.self_ty().has_non_region_infer() {
return ecx.make_canonical_response(Certainty::Maybe(MaybeCause::Ambiguity));
return ecx.make_canonical_response(Certainty::AMBIGUOUS);
}

let tcx = ecx.tcx();
Expand Down Expand Up @@ -171,7 +171,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
.to_predicate(ecx.tcx());
Self::consider_assumption(ecx, goal, pred)
} else {
ecx.make_canonical_response(Certainty::Maybe(MaybeCause::Ambiguity))
ecx.make_canonical_response(Certainty::AMBIGUOUS)
}
}

Expand Down
3 changes: 3 additions & 0 deletions src/tools/compiletest/src/common.rs
Original file line number Diff line number Diff line change
Expand Up @@ -123,6 +123,7 @@ pub enum FailMode {
pub enum CompareMode {
Polonius,
Chalk,
NextSolver,
SplitDwarf,
SplitDwarfSingle,
}
Expand All @@ -132,6 +133,7 @@ impl CompareMode {
match *self {
CompareMode::Polonius => "polonius",
CompareMode::Chalk => "chalk",
CompareMode::NextSolver => "next-solver",
CompareMode::SplitDwarf => "split-dwarf",
CompareMode::SplitDwarfSingle => "split-dwarf-single",
}
Expand All @@ -141,6 +143,7 @@ impl CompareMode {
match s.as_str() {
"polonius" => CompareMode::Polonius,
"chalk" => CompareMode::Chalk,
"next-solver" => CompareMode::NextSolver,
"split-dwarf" => CompareMode::SplitDwarf,
"split-dwarf-single" => CompareMode::SplitDwarfSingle,
x => panic!("unknown --compare-mode option: {}", x),
Expand Down
1 change: 1 addition & 0 deletions src/tools/compiletest/src/header.rs
Original file line number Diff line number Diff line change
Expand Up @@ -701,6 +701,7 @@ impl Config {
match self.compare_mode {
Some(CompareMode::Polonius) => name == "compare-mode-polonius",
Some(CompareMode::Chalk) => name == "compare-mode-chalk",
Some(CompareMode::NextSolver) => name == "compare-mode-next-solver",
Some(CompareMode::SplitDwarf) => name == "compare-mode-split-dwarf",
Some(CompareMode::SplitDwarfSingle) => name == "compare-mode-split-dwarf-single",
None => false,
Expand Down
3 changes: 3 additions & 0 deletions src/tools/compiletest/src/runtest.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2013,6 +2013,9 @@ impl<'test> TestCx<'test> {
Some(CompareMode::Chalk) => {
rustc.args(&["-Ztrait-solver=chalk"]);
}
Some(CompareMode::NextSolver) => {
rustc.args(&["-Ztrait-solver=next"]);
}
Some(CompareMode::SplitDwarf) if self.config.target.contains("windows") => {
rustc.args(&["-Csplit-debuginfo=unpacked", "-Zunstable-options"]);
}
Expand Down