From 8434b43a7f9886a0b0e5f36b115d6c26dde4953d Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Tue, 24 Jan 2023 23:57:26 +0000 Subject: [PATCH 1/2] Report the right fulfillment errors --- .../src/solve/fulfill.rs | 67 ++++++++++++++++--- 1 file changed, 57 insertions(+), 10 deletions(-) diff --git a/compiler/rustc_trait_selection/src/solve/fulfill.rs b/compiler/rustc_trait_selection/src/solve/fulfill.rs index d59fa71406c31..278024b22760a 100644 --- a/compiler/rustc_trait_selection/src/solve/fulfill.rs +++ b/compiler/rustc_trait_selection/src/solve/fulfill.rs @@ -1,13 +1,14 @@ use std::mem; -use super::{Certainty, InferCtxtEvalExt}; -use rustc_infer::{ - infer::InferCtxt, - traits::{ - query::NoSolution, FulfillmentError, FulfillmentErrorCode, PredicateObligation, - SelectionError, TraitEngine, - }, +use rustc_infer::infer::InferCtxt; +use rustc_infer::traits::{ + query::NoSolution, FulfillmentError, FulfillmentErrorCode, MismatchedProjectionTypes, + PredicateObligation, SelectionError, TraitEngine, }; +use rustc_middle::ty; +use rustc_middle::ty::error::{ExpectedFound, TypeError}; + +use super::{Certainty, InferCtxtEvalExt}; /// A trait engine using the new trait solver. /// @@ -70,9 +71,55 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> { Err(NoSolution) => { errors.push(FulfillmentError { obligation: obligation.clone(), - code: FulfillmentErrorCode::CodeSelectionError( - SelectionError::Unimplemented, - ), + code: match goal.predicate.kind().skip_binder() { + ty::PredicateKind::Clause(ty::Clause::Projection(_)) => { + FulfillmentErrorCode::CodeProjectionError( + // FIXME: This could be a `Sorts` if the term is a type + MismatchedProjectionTypes { err: TypeError::Mismatch }, + ) + } + ty::PredicateKind::Subtype(pred) => { + let (a, b) = infcx.replace_bound_vars_with_placeholders( + goal.predicate.kind().rebind((pred.a, pred.b)), + ); + let expected_found = ExpectedFound::new(true, a, b); + FulfillmentErrorCode::CodeSubtypeError( + expected_found, + TypeError::Sorts(expected_found), + ) + } + ty::PredicateKind::Coerce(pred) => { + let (a, b) = infcx.replace_bound_vars_with_placeholders( + goal.predicate.kind().rebind((pred.a, pred.b)), + ); + let expected_found = ExpectedFound::new(false, a, b); + FulfillmentErrorCode::CodeSubtypeError( + expected_found, + TypeError::Sorts(expected_found), + ) + } + ty::PredicateKind::ConstEquate(a, b) => { + let (a, b) = infcx.replace_bound_vars_with_placeholders( + goal.predicate.kind().rebind((a, b)), + ); + let expected_found = ExpectedFound::new(true, a, b); + FulfillmentErrorCode::CodeConstEquateError( + expected_found, + TypeError::ConstMismatch(expected_found), + ) + } + ty::PredicateKind::Clause(_) + | ty::PredicateKind::WellFormed(_) + | ty::PredicateKind::ObjectSafe(_) + | ty::PredicateKind::ClosureKind(_, _, _) + | ty::PredicateKind::ConstEvaluatable(_) + | ty::PredicateKind::TypeWellFormedFromEnv(_) + | ty::PredicateKind::Ambiguous => { + FulfillmentErrorCode::CodeSelectionError( + SelectionError::Unimplemented, + ) + } + }, root_obligation: obligation, }); continue; From d600b94ebb5a418ba011797b85045975f18f90dd Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Tue, 24 Jan 2023 23:38:20 +0000 Subject: [PATCH 2/2] Implement Generator and Future --- .../src/solve/assembly.rs | 14 ++++ .../src/solve/project_goals.rs | 69 ++++++++++++++++++- .../src/solve/trait_goals.rs | 44 ++++++++++++ .../solve/trait_goals/structural_traits.rs | 1 + tests/ui/traits/new-solver/async.fail.stderr | 17 +++++ tests/ui/traits/new-solver/async.rs | 19 +++++ .../traits/new-solver/generator.fail.stderr | 64 +++++++++++++++++ tests/ui/traits/new-solver/generator.rs | 32 +++++++++ 8 files changed, 259 insertions(+), 1 deletion(-) create mode 100644 tests/ui/traits/new-solver/async.fail.stderr create mode 100644 tests/ui/traits/new-solver/async.rs create mode 100644 tests/ui/traits/new-solver/generator.fail.stderr create mode 100644 tests/ui/traits/new-solver/generator.rs diff --git a/compiler/rustc_trait_selection/src/solve/assembly.rs b/compiler/rustc_trait_selection/src/solve/assembly.rs index 0b642fcba2812..baff0f8630ee5 100644 --- a/compiler/rustc_trait_selection/src/solve/assembly.rs +++ b/compiler/rustc_trait_selection/src/solve/assembly.rs @@ -138,6 +138,16 @@ pub(super) trait GoalKind<'tcx>: TypeFoldable<'tcx> + Copy + Eq { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx>; + + fn consider_builtin_future_candidate( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + ) -> QueryResult<'tcx>; + + fn consider_builtin_generator_candidate( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + ) -> QueryResult<'tcx>; } impl<'tcx> EvalCtxt<'_, 'tcx> { @@ -266,6 +276,10 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { G::consider_builtin_tuple_candidate(self, goal) } else if lang_items.pointee_trait() == Some(trait_def_id) { G::consider_builtin_pointee_candidate(self, goal) + } else if lang_items.future_trait() == Some(trait_def_id) { + G::consider_builtin_future_candidate(self, goal) + } else if lang_items.gen_trait() == Some(trait_def_id) { + G::consider_builtin_generator_candidate(self, goal) } else { Err(NoSolution) }; diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs index e5072d8e2d152..4a9b95af4a27c 100644 --- a/compiler/rustc_trait_selection/src/solve/project_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs @@ -16,7 +16,7 @@ use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams}; use rustc_middle::ty::{self, Ty, TyCtxt}; use rustc_middle::ty::{ProjectionPredicate, TypeSuperVisitable, TypeVisitor}; use rustc_middle::ty::{ToPredicate, TypeVisitable}; -use rustc_span::DUMMY_SP; +use rustc_span::{sym, DUMMY_SP}; use std::iter; use std::ops::ControlFlow; @@ -482,6 +482,73 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { ecx.evaluate_all_and_make_canonical_response(nested_goals) }) } + + fn consider_builtin_future_candidate( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + ) -> QueryResult<'tcx> { + let self_ty = goal.predicate.self_ty(); + let ty::Generator(def_id, substs, _) = *self_ty.kind() else { + return Err(NoSolution); + }; + + // Generators are not futures unless they come from `async` desugaring + let tcx = ecx.tcx(); + if !tcx.generator_is_async(def_id) { + return Err(NoSolution); + } + + let term = substs.as_generator().return_ty().into(); + + Self::consider_assumption( + ecx, + goal, + ty::Binder::dummy(ty::ProjectionPredicate { + projection_ty: ecx.tcx().mk_alias_ty(goal.predicate.def_id(), [self_ty]), + term, + }) + .to_predicate(tcx), + ) + } + + fn consider_builtin_generator_candidate( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + ) -> QueryResult<'tcx> { + let self_ty = goal.predicate.self_ty(); + let ty::Generator(def_id, substs, _) = *self_ty.kind() else { + return Err(NoSolution); + }; + + // `async`-desugared generators do not implement the generator trait + let tcx = ecx.tcx(); + if tcx.generator_is_async(def_id) { + return Err(NoSolution); + } + + let generator = substs.as_generator(); + + let name = tcx.associated_item(goal.predicate.def_id()).name; + let term = if name == sym::Return { + generator.return_ty().into() + } else if name == sym::Yield { + generator.yield_ty().into() + } else { + bug!("unexpected associated item `<{self_ty} as Generator>::{name}`") + }; + + Self::consider_assumption( + ecx, + goal, + ty::Binder::dummy(ty::ProjectionPredicate { + projection_ty: ecx + .tcx() + .mk_alias_ty(goal.predicate.def_id(), [self_ty, generator.resume_ty()]), + term, + }) + .to_predicate(tcx), + ) + } } /// This behavior is also implemented in `rustc_ty_utils` and in the old `project` code. diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs index 67bd249566546..d74857dc4b480 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs @@ -192,6 +192,50 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ) -> QueryResult<'tcx> { ecx.make_canonical_response(Certainty::Yes) } + + fn consider_builtin_future_candidate( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + ) -> QueryResult<'tcx> { + let ty::Generator(def_id, _, _) = *goal.predicate.self_ty().kind() else { + return Err(NoSolution); + }; + + // Generators are not futures unless they come from `async` desugaring + let tcx = ecx.tcx(); + if !tcx.generator_is_async(def_id) { + return Err(NoSolution); + } + + // Async generator unconditionally implement `Future` + ecx.make_canonical_response(Certainty::Yes) + } + + fn consider_builtin_generator_candidate( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + ) -> QueryResult<'tcx> { + let self_ty = goal.predicate.self_ty(); + let ty::Generator(def_id, substs, _) = *self_ty.kind() else { + return Err(NoSolution); + }; + + // `async`-desugared generators do not implement the generator trait + let tcx = ecx.tcx(); + if tcx.generator_is_async(def_id) { + return Err(NoSolution); + } + + let generator = substs.as_generator(); + Self::consider_assumption( + ecx, + goal, + ty::Binder::dummy( + tcx.mk_trait_ref(goal.predicate.def_id(), [self_ty, generator.resume_ty()]), + ) + .to_predicate(tcx), + ) + } } impl<'tcx> EvalCtxt<'_, 'tcx> { diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs b/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs index a11cd13cb0856..162953180c75c 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs @@ -173,6 +173,7 @@ pub(super) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>( } } +// Returns a binder of the tupled inputs types and output type from a builtin callable type. pub(crate) fn extract_tupled_inputs_and_output_from_callable<'tcx>( tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>, diff --git a/tests/ui/traits/new-solver/async.fail.stderr b/tests/ui/traits/new-solver/async.fail.stderr new file mode 100644 index 0000000000000..b395c23ae0057 --- /dev/null +++ b/tests/ui/traits/new-solver/async.fail.stderr @@ -0,0 +1,17 @@ +error[E0271]: expected `[async block@$DIR/async.rs:12:17: 12:25]` to be a future that resolves to `i32`, but it resolves to `()` + --> $DIR/async.rs:12:17 + | +LL | needs_async(async {}); + | ----------- ^^^^^^^^ expected `i32`, found `()` + | | + | required by a bound introduced by this call + | +note: required by a bound in `needs_async` + --> $DIR/async.rs:8:31 + | +LL | fn needs_async(_: impl Future) {} + | ^^^^^^^^^^^^ required by this bound in `needs_async` + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0271`. diff --git a/tests/ui/traits/new-solver/async.rs b/tests/ui/traits/new-solver/async.rs new file mode 100644 index 0000000000000..195cc35cad2ad --- /dev/null +++ b/tests/ui/traits/new-solver/async.rs @@ -0,0 +1,19 @@ +// compile-flags: -Ztrait-solver=next +// edition: 2021 +// revisions: pass fail +//[pass] check-pass + +use std::future::Future; + +fn needs_async(_: impl Future) {} + +#[cfg(fail)] +fn main() { + needs_async(async {}); + //[fail]~^ ERROR to be a future that resolves to `i32`, but it resolves to `()` +} + +#[cfg(pass)] +fn main() { + needs_async(async { 1i32 }); +} diff --git a/tests/ui/traits/new-solver/generator.fail.stderr b/tests/ui/traits/new-solver/generator.fail.stderr new file mode 100644 index 0000000000000..d94d41e3587b6 --- /dev/null +++ b/tests/ui/traits/new-solver/generator.fail.stderr @@ -0,0 +1,64 @@ +error[E0277]: the trait bound `[generator@$DIR/generator.rs:18:21: 18:23]: Generator` is not satisfied + --> $DIR/generator.rs:18:21 + | +LL | needs_generator(|| { + | _____---------------_^ + | | | + | | required by a bound introduced by this call +LL | | +LL | | +LL | | +LL | | yield (); +LL | | }); + | |_____^ the trait `Generator` is not implemented for `[generator@$DIR/generator.rs:18:21: 18:23]` + | +note: required by a bound in `needs_generator` + --> $DIR/generator.rs:14:28 + | +LL | fn needs_generator(_: impl Generator) {} + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `needs_generator` + +error[E0271]: type mismatch resolving `<[generator@$DIR/generator.rs:18:21: 18:23] as Generator>::Yield == B` + --> $DIR/generator.rs:18:21 + | +LL | needs_generator(|| { + | _____---------------_^ + | | | + | | required by a bound introduced by this call +LL | | +LL | | +LL | | +LL | | yield (); +LL | | }); + | |_____^ types differ + | +note: required by a bound in `needs_generator` + --> $DIR/generator.rs:14:41 + | +LL | fn needs_generator(_: impl Generator) {} + | ^^^^^^^^^ required by this bound in `needs_generator` + +error[E0271]: type mismatch resolving `<[generator@$DIR/generator.rs:18:21: 18:23] as Generator>::Return == C` + --> $DIR/generator.rs:18:21 + | +LL | needs_generator(|| { + | _____---------------_^ + | | | + | | required by a bound introduced by this call +LL | | +LL | | +LL | | +LL | | yield (); +LL | | }); + | |_____^ types differ + | +note: required by a bound in `needs_generator` + --> $DIR/generator.rs:14:52 + | +LL | fn needs_generator(_: impl Generator) {} + | ^^^^^^^^^^ required by this bound in `needs_generator` + +error: aborting due to 3 previous errors + +Some errors have detailed explanations: E0271, E0277. +For more information about an error, try `rustc --explain E0271`. diff --git a/tests/ui/traits/new-solver/generator.rs b/tests/ui/traits/new-solver/generator.rs new file mode 100644 index 0000000000000..364373ca8be71 --- /dev/null +++ b/tests/ui/traits/new-solver/generator.rs @@ -0,0 +1,32 @@ +// compile-flags: -Ztrait-solver=next +// edition: 2021 +// revisions: pass fail +//[pass] check-pass + +#![feature(generator_trait, generators)] + +use std::ops::Generator; + +struct A; +struct B; +struct C; + +fn needs_generator(_: impl Generator) {} + +#[cfg(fail)] +fn main() { + needs_generator(|| { + //[fail]~^ ERROR Generator` is not satisfied + //[fail]~| ERROR as Generator>::Yield == B` + //[fail]~| ERROR as Generator>::Return == C` + yield (); + }); +} + +#[cfg(pass)] +fn main() { + needs_generator(|_: A| { + let _: A = yield B; + C + }) +}