diff options
4 files changed, 126 insertions, 3 deletions
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs index 7855749e586..8e4e708b73c 100644 --- a/compiler/rustc_middle/src/ty/mod.rs +++ b/compiler/rustc_middle/src/ty/mod.rs @@ -861,6 +861,11 @@ impl<'tcx> PolyTraitPredicate<'tcx> { pub fn is_const_if_const(self) -> bool { self.skip_binder().is_const_if_const() } + + #[inline] + pub fn polarity(self) -> ImplPolarity { + self.skip_binder().polarity + } } /// `A: B` diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs index 8e7097ce4a7..c97473e6241 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs @@ -86,8 +86,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ) -> QueryResult<'tcx> { if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred() && poly_trait_pred.def_id() == goal.predicate.def_id() + && poly_trait_pred.polarity() == goal.predicate.polarity { - // FIXME: Constness and polarity + // FIXME: Constness ecx.probe(|ecx| { let assumption_trait_pred = ecx.instantiate_binder_with_infer(poly_trait_pred); @@ -111,6 +112,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ) -> QueryResult<'tcx> { if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred() && poly_trait_pred.def_id() == goal.predicate.def_id() + && poly_trait_pred.polarity() == goal.predicate.polarity { // FIXME: Constness and polarity ecx.probe(|ecx| { @@ -147,6 +149,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + if let Some(result) = ecx.disqualify_auto_trait_candidate_due_to_possible_impl(goal) { return result; } @@ -161,6 +167,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let tcx = ecx.tcx(); ecx.probe(|ecx| { @@ -176,6 +186,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + ecx.probe_and_evaluate_goal_for_constituent_tys( goal, structural_traits::instantiate_constituent_tys_for_sized_trait, @@ -186,6 +200,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + ecx.probe_and_evaluate_goal_for_constituent_tys( goal, structural_traits::instantiate_constituent_tys_for_copy_clone_trait, @@ -196,6 +214,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + if goal.predicate.self_ty().has_non_region_infer() { return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); } @@ -217,6 +239,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + if let ty::FnPtr(..) = goal.predicate.self_ty().kind() { ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } else { @@ -229,6 +255,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { goal: Goal<'tcx, Self>, goal_kind: ty::ClosureKind, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let tcx = ecx.tcx(); let tupled_inputs_and_output = match structural_traits::extract_tupled_inputs_and_output_from_callable( @@ -259,6 +289,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + if let ty::Tuple(..) = goal.predicate.self_ty().kind() { ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } else { @@ -268,8 +302,12 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_pointee_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, - _goal: Goal<'tcx, Self>, + goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } @@ -277,6 +315,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let ty::Generator(def_id, _, _) = *goal.predicate.self_ty().kind() else { return Err(NoSolution); }; @@ -297,6 +339,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let self_ty = goal.predicate.self_ty(); let ty::Generator(def_id, substs, _) = *self_ty.kind() else { return Err(NoSolution); @@ -326,6 +372,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let tcx = ecx.tcx(); let a_ty = goal.predicate.self_ty(); let b_ty = goal.predicate.trait_ref.substs.type_at(1); @@ -447,6 +497,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> Vec<CanonicalResponse<'tcx>> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return vec![]; + } + let tcx = ecx.tcx(); let a_ty = goal.predicate.self_ty(); @@ -521,8 +575,12 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_discriminant_kind_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, - _goal: Goal<'tcx, Self>, + goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + // `DiscriminantKind` is automatically implemented for every type. ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } @@ -531,6 +589,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + if !goal.param_env.is_const() { // `Destruct` is automatically implemented for every type in // non-const environments. @@ -545,6 +607,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + // `rustc_transmute` does not have support for type or const params if goal.has_non_region_placeholders() { return Err(NoSolution); diff --git a/tests/ui/traits/new-solver/negative-coherence-bounds.rs b/tests/ui/traits/new-solver/negative-coherence-bounds.rs new file mode 100644 index 00000000000..5436b02c3de --- /dev/null +++ b/tests/ui/traits/new-solver/negative-coherence-bounds.rs @@ -0,0 +1,40 @@ +// check-pass + +// This test verifies that negative trait predicate cannot be satisfied from a +// positive param-env candidate. + +// Negative coherence is one of the only places where we actually construct and +// evaluate negative predicates. Specifically, when verifying whether the first +// and second impls below overlap, we do not want to consider them disjoint, +// otherwise the second impl would be missing an associated type `type Item` +// which is provided by the first impl that it is specializing. + +#![feature(specialization)] +//~^ WARN the feature `specialization` is incomplete +#![feature(with_negative_coherence)] + +trait BoxIter { + type Item; + + fn last(self) -> Option<Self::Item>; +} + +impl<I: Iterator + ?Sized> BoxIter for Box<I> { + type Item = I::Item; + + default fn last(self) -> Option<I::Item> { + todo!() + } +} + +// When checking that this impl does/doesn't overlap the one above, we evaluate +// a negative version of all of the where-clause predicates of the impl below. +// For `I: !Iterator`, we should make sure that the param-env clause `I: Iterator` +// from above doesn't satisfy this predicate. +impl<I: Iterator> BoxIter for Box<I> { + fn last(self) -> Option<I::Item> { + (*self).last() + } +} + +fn main() {} diff --git a/tests/ui/traits/new-solver/negative-coherence-bounds.stderr b/tests/ui/traits/new-solver/negative-coherence-bounds.stderr new file mode 100644 index 00000000000..4127f51f56d --- /dev/null +++ b/tests/ui/traits/new-solver/negative-coherence-bounds.stderr @@ -0,0 +1,12 @@ +warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/negative-coherence-bounds.rs:12:12 + | +LL | #![feature(specialization)] + | ^^^^^^^^^^^^^^ + | + = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information + = help: consider using `min_specialization` instead, which is more stable and complete + = note: `#[warn(incomplete_features)]` on by default + +warning: 1 warning emitted + |