From 444cbcd729e4b55602fedcaef7fe902316d8ab49 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Fri, 20 Jan 2023 18:38:33 +0000 Subject: [PATCH] Address goal nits --- .../src/solve/assembly.rs | 6 +- .../rustc_trait_selection/src/solve/mod.rs | 73 ++++++++++++------- .../src/solve/project_goals.rs | 7 +- .../src/solve/trait_goals.rs | 6 +- 4 files changed, 54 insertions(+), 38 deletions(-) diff --git a/compiler/rustc_trait_selection/src/solve/assembly.rs b/compiler/rustc_trait_selection/src/solve/assembly.rs index 31c1bc9ecc0..cdb72d49834 100644 --- a/compiler/rustc_trait_selection/src/solve/assembly.rs +++ b/compiler/rustc_trait_selection/src/solve/assembly.rs @@ -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; @@ -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(), }]; } diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs index e89d3df04db..da2a1a19957 100644 --- a/compiler/rustc_trait_selection/src/solve/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/mod.rs @@ -19,6 +19,7 @@ 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}; @@ -27,7 +28,7 @@ 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, SubtypePredicate, ToPredicate, TypeOutlivesPredicate, + CoercePredicate, RegionOutlivesPredicate, SubtypePredicate, ToPredicate, TypeOutlivesPredicate, }; use rustc_span::DUMMY_SP; @@ -89,6 +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 { @@ -248,21 +251,15 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { ty::PredicateKind::Subtype(predicate) => { self.compute_subtype_goal(Goal { param_env, predicate }) } - ty::PredicateKind::Coerce(predicate) => self.compute_subtype_goal(Goal { - param_env, - predicate: SubtypePredicate { - a_is_expected: true, - a: predicate.a, - b: predicate.b, - }, - }), - ty::PredicateKind::ClosureKind(_, substs, kind) => self.compute_closure_kind_goal( - substs.as_closure().kind_ty().to_opt_closure_kind(), - kind, - ), - ty::PredicateKind::Ambiguous => { - self.make_canonical_response(Certainty::Maybe(MaybeCause::Ambiguity)) + 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(_) @@ -296,28 +293,50 @@ impl<'a, 'tcx> EvalCtxt<'a, '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> { - 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(), - ) - }) + 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, - found_kind: Option, - expected_kind: ty::ClosureKind, + 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::Maybe(MaybeCause::Ambiguity)); + return self.make_canonical_response(Certainty::AMBIGUOUS); }; if found_kind.extends(expected_kind) { self.make_canonical_response(Certainty::Yes) diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs index e39fa053392..32e15f03998 100644 --- a/compiler/rustc_trait_selection/src/solve/project_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs @@ -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; @@ -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() { @@ -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) } } diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs index 9985d7181bb..4b6d673c999 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs @@ -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; @@ -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(); @@ -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) } }