From 6402c98621ab620a16adac072abc10779cf60573 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Thu, 16 Feb 2023 03:04:08 +0000 Subject: [PATCH] Add consider_implied_clause --- .../src/solve/assembly.rs | 34 ++---- .../src/solve/project_goals.rs | 115 +++++++++--------- .../src/solve/trait_goals.rs | 50 ++++---- 3 files changed, 97 insertions(+), 102 deletions(-) diff --git a/compiler/rustc_trait_selection/src/solve/assembly.rs b/compiler/rustc_trait_selection/src/solve/assembly.rs index a9e0c5509a5e..841169ac78d7 100644 --- a/compiler/rustc_trait_selection/src/solve/assembly.rs +++ b/compiler/rustc_trait_selection/src/solve/assembly.rs @@ -90,30 +90,22 @@ pub(super) trait GoalKind<'tcx>: TypeFoldable<'tcx> + Copy + Eq { fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId; + // Consider a clause, which consists of a "assumption" and some "requirements", + // to satisfy a goal. If the requirements hold, then attempt to satisfy our + // goal by equating it with the assumption. + fn consider_implied_clause( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + assumption: ty::Predicate<'tcx>, + requirements: impl IntoIterator>>, + ) -> QueryResult<'tcx>; + fn consider_impl_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, impl_def_id: DefId, ) -> QueryResult<'tcx>; - // Consider a predicate we know holds (`assumption`) against a goal we're trying to prove. - fn consider_assumption( - ecx: &mut EvalCtxt<'_, 'tcx>, - goal: Goal<'tcx, Self>, - assumption: ty::Predicate<'tcx>, - ) -> QueryResult<'tcx> { - Self::consider_assumption_with_certainty(ecx, goal, assumption, Certainty::Yes) - } - - // Consider a predicate we know holds (`assumption`) against a goal, unifying with - // the `assumption_certainty` if it satisfies the goal. - fn consider_assumption_with_certainty( - ecx: &mut EvalCtxt<'_, 'tcx>, - goal: Goal<'tcx, Self>, - assumption: ty::Predicate<'tcx>, - assumption_certainty: Certainty, - ) -> QueryResult<'tcx>; - // A type implements an `auto trait` if its components do as well. These components // are given by built-in rules from [`instantiate_constituent_tys_for_auto_trait`]. fn consider_auto_trait_candidate( @@ -367,7 +359,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { candidates: &mut Vec>, ) { for (i, assumption) in goal.param_env.caller_bounds().iter().enumerate() { - match G::consider_assumption(self, goal, assumption) { + match G::consider_implied_clause(self, goal, assumption, []) { Ok(result) => { candidates.push(Candidate { source: CandidateSource::ParamEnv(i), result }) } @@ -414,7 +406,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { for assumption in self.tcx().item_bounds(alias_ty.def_id).subst(self.tcx(), alias_ty.substs) { - match G::consider_assumption(self, goal, assumption) { + match G::consider_implied_clause(self, goal, assumption, []) { Ok(result) => { candidates.push(Candidate { source: CandidateSource::AliasBound, result }) } @@ -464,7 +456,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { for assumption in elaborate_predicates(tcx, bounds.iter().map(|bound| bound.with_self_ty(tcx, self_ty))) { - match G::consider_assumption(self, goal, assumption.predicate) { + match G::consider_implied_clause(self, goal, assumption.predicate, []) { Ok(result) => { candidates.push(Candidate { source: CandidateSource::BuiltinImpl, result }) } diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs index adf8a1690c83..48153b465b7e 100644 --- a/compiler/rustc_trait_selection/src/solve/project_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs @@ -168,6 +168,37 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { self.trait_def_id(tcx) } + fn consider_implied_clause( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + assumption: ty::Predicate<'tcx>, + requirements: impl IntoIterator>>, + ) -> QueryResult<'tcx> { + if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred() + && poly_projection_pred.projection_def_id() == goal.predicate.def_id() + { + ecx.infcx.probe(|_| { + let assumption_projection_pred = + ecx.infcx.instantiate_binder_with_infer(poly_projection_pred); + let mut nested_goals = ecx.infcx.eq( + goal.param_env, + goal.predicate.projection_ty, + assumption_projection_pred.projection_ty, + )?; + nested_goals.extend(requirements); + let subst_certainty = ecx.evaluate_all(nested_goals)?; + + ecx.eq_term_and_make_canonical_response( + goal, + subst_certainty, + assumption_projection_pred.term, + ) + }) + } else { + Err(NoSolution) + } + } + fn consider_impl_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, ProjectionPredicate<'tcx>>, @@ -260,36 +291,6 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { }) } - fn consider_assumption_with_certainty( - ecx: &mut EvalCtxt<'_, 'tcx>, - goal: Goal<'tcx, Self>, - assumption: ty::Predicate<'tcx>, - assumption_certainty: Certainty, - ) -> QueryResult<'tcx> { - if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred() - && poly_projection_pred.projection_def_id() == goal.predicate.def_id() - { - ecx.infcx.probe(|_| { - let assumption_projection_pred = - ecx.infcx.instantiate_binder_with_infer(poly_projection_pred); - let nested_goals = ecx.infcx.eq( - goal.param_env, - goal.predicate.projection_ty, - assumption_projection_pred.projection_ty, - )?; - let subst_certainty = ecx.evaluate_all(nested_goals)?; - - ecx.eq_term_and_make_canonical_response( - goal, - subst_certainty.unify_and(assumption_certainty), - assumption_projection_pred.term, - ) - }) - } else { - Err(NoSolution) - } - } - fn consider_auto_trait_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, @@ -331,31 +332,27 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { goal_kind: ty::ClosureKind, ) -> QueryResult<'tcx> { let tcx = ecx.tcx(); - if let Some(tupled_inputs_and_output) = - structural_traits::extract_tupled_inputs_and_output_from_callable( - tcx, - goal.predicate.self_ty(), - goal_kind, - )? - { - // A built-in `Fn` trait needs to check that its output is `Sized` - // (FIXME: technically we only need to check this if the type is a fn ptr...) - let output_is_sized_pred = tupled_inputs_and_output - .map_bound(|(_, output)| tcx.at(DUMMY_SP).mk_trait_ref(LangItem::Sized, [output])); - let (_, output_is_sized_certainty) = - ecx.evaluate_goal(goal.with(tcx, output_is_sized_pred))?; + let Some(tupled_inputs_and_output) = + structural_traits::extract_tupled_inputs_and_output_from_callable( + tcx, + goal.predicate.self_ty(), + goal_kind, + )? else { + return ecx.make_canonical_response(Certainty::AMBIGUOUS); + }; + let output_is_sized_pred = tupled_inputs_and_output + .map_bound(|(_, output)| tcx.at(DUMMY_SP).mk_trait_ref(LangItem::Sized, [output])); - let pred = tupled_inputs_and_output - .map_bound(|(inputs, output)| ty::ProjectionPredicate { - projection_ty: tcx - .mk_alias_ty(goal.predicate.def_id(), [goal.predicate.self_ty(), inputs]), - term: output.into(), - }) - .to_predicate(tcx); - Self::consider_assumption_with_certainty(ecx, goal, pred, output_is_sized_certainty) - } else { - ecx.make_canonical_response(Certainty::AMBIGUOUS) - } + let pred = tupled_inputs_and_output + .map_bound(|(inputs, output)| ty::ProjectionPredicate { + projection_ty: tcx + .mk_alias_ty(goal.predicate.def_id(), [goal.predicate.self_ty(), inputs]), + term: output.into(), + }) + .to_predicate(tcx); + // A built-in `Fn` impl only holds if the output is sized. + // (FIXME: technically we only need to check this if the type is a fn ptr...) + Self::consider_implied_clause(ecx, goal, pred, [goal.with(tcx, output_is_sized_pred)]) } fn consider_builtin_tuple_candidate( @@ -474,7 +471,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { let term = substs.as_generator().return_ty().into(); - Self::consider_assumption( + Self::consider_implied_clause( ecx, goal, ty::Binder::dummy(ty::ProjectionPredicate { @@ -482,6 +479,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { term, }) .to_predicate(tcx), + // Technically, we need to check that the future type is Sized, + // but that's already proven by the generator being WF. + [], ) } @@ -511,7 +511,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { bug!("unexpected associated item `<{self_ty} as Generator>::{name}`") }; - Self::consider_assumption( + Self::consider_implied_clause( ecx, goal, ty::Binder::dummy(ty::ProjectionPredicate { @@ -521,6 +521,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { term, }) .to_predicate(tcx), + // Technically, we need to check that the future type is Sized, + // but that's already proven by the generator being WF. + [], ) } diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs index dd47a5ae1507..f2f25ef850a9 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs @@ -62,11 +62,11 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { }) } - fn consider_assumption_with_certainty( + fn consider_implied_clause( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, assumption: ty::Predicate<'tcx>, - assumption_certainty: Certainty, + requirements: impl IntoIterator>>, ) -> QueryResult<'tcx> { if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred() && poly_trait_pred.def_id() == goal.predicate.def_id() @@ -75,14 +75,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx.infcx.probe(|_| { let assumption_trait_pred = ecx.infcx.instantiate_binder_with_infer(poly_trait_pred); - let nested_goals = ecx.infcx.eq( + let mut nested_goals = ecx.infcx.eq( goal.param_env, goal.predicate.trait_ref, assumption_trait_pred.trait_ref, )?; - ecx.evaluate_all(nested_goals).and_then(|certainty| { - ecx.make_canonical_response(certainty.unify_and(assumption_certainty)) - }) + nested_goals.extend(requirements); + ecx.evaluate_all_and_make_canonical_response(nested_goals) }) } else { Err(NoSolution) @@ -178,29 +177,25 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { goal_kind: ty::ClosureKind, ) -> QueryResult<'tcx> { let tcx = ecx.tcx(); - if let Some(tupled_inputs_and_output) = + let Some(tupled_inputs_and_output) = structural_traits::extract_tupled_inputs_and_output_from_callable( tcx, goal.predicate.self_ty(), goal_kind, - )? - { - // A built-in `Fn` trait needs to check that its output is `Sized` - // (FIXME: technically we only need to check this if the type is a fn ptr...) - let output_is_sized_pred = tupled_inputs_and_output - .map_bound(|(_, output)| tcx.at(DUMMY_SP).mk_trait_ref(LangItem::Sized, [output])); - let (_, output_is_sized_certainty) = - ecx.evaluate_goal(goal.with(tcx, output_is_sized_pred))?; + )? else { + return ecx.make_canonical_response(Certainty::AMBIGUOUS); + }; + let output_is_sized_pred = tupled_inputs_and_output + .map_bound(|(_, output)| tcx.at(DUMMY_SP).mk_trait_ref(LangItem::Sized, [output])); - let pred = tupled_inputs_and_output - .map_bound(|(inputs, _)| { - tcx.mk_trait_ref(goal.predicate.def_id(), [goal.predicate.self_ty(), inputs]) - }) - .to_predicate(tcx); - Self::consider_assumption_with_certainty(ecx, goal, pred, output_is_sized_certainty) - } else { - ecx.make_canonical_response(Certainty::AMBIGUOUS) - } + let pred = tupled_inputs_and_output + .map_bound(|(inputs, _)| { + tcx.mk_trait_ref(goal.predicate.def_id(), [goal.predicate.self_ty(), inputs]) + }) + .to_predicate(tcx); + // A built-in `Fn` impl only holds if the output is sized. + // (FIXME: technically we only need to check this if the type is a fn ptr...) + Self::consider_implied_clause(ecx, goal, pred, [goal.with(tcx, output_is_sized_pred)]) } fn consider_builtin_tuple_candidate( @@ -236,6 +231,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { } // Async generator unconditionally implement `Future` + // Technically, we need to check that the future output type is Sized, + // but that's already proven by the generator being WF. ecx.make_canonical_response(Certainty::Yes) } @@ -255,13 +252,16 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { } let generator = substs.as_generator(); - Self::consider_assumption( + Self::consider_implied_clause( ecx, goal, ty::Binder::dummy( tcx.mk_trait_ref(goal.predicate.def_id(), [self_ty, generator.resume_ty()]), ) .to_predicate(tcx), + // Technically, we need to check that the generator types are Sized, + // but that's already proven by the generator being WF. + [], ) }