From 69f360d00ca24978ad81b52c5815b5a6a6e2a8a7 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Sat, 16 Dec 2023 19:21:43 +0000 Subject: [PATCH] Check FnPtr/FnDef built-in fn traits correctly with effects --- compiler/rustc_middle/src/traits/select.rs | 2 +- .../src/traits/project.rs | 39 +++++++++++++++---- .../src/traits/select/candidate_assembly.rs | 20 ++++++---- .../src/traits/select/confirmation.rs | 11 +++--- .../src/traits/select/mod.rs | 6 ++- .../rustc_trait_selection/src/traits/util.rs | 15 ++++++- .../effects/minicore.rs | 15 ++++++- 7 files changed, 84 insertions(+), 24 deletions(-) diff --git a/compiler/rustc_middle/src/traits/select.rs b/compiler/rustc_middle/src/traits/select.rs index c52103eb247e1..734c2b61c07fc 100644 --- a/compiler/rustc_middle/src/traits/select.rs +++ b/compiler/rustc_middle/src/traits/select.rs @@ -153,7 +153,7 @@ pub enum SelectionCandidate<'tcx> { /// Implementation of a `Fn`-family trait by one of the anonymous /// types generated for a fn pointer type (e.g., `fn(int) -> int`) FnPointerCandidate { - is_const: bool, + fn_host_effect: ty::Const<'tcx>, }, TraitAliasCandidate, diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index d5635812c7405..a1b0ada0e8a8c 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -2327,8 +2327,9 @@ fn confirm_fn_pointer_candidate<'cx, 'tcx>( obligation: &ProjectionTyObligation<'tcx>, nested: Vec>, ) -> Progress<'tcx> { + let tcx = selcx.tcx(); let fn_type = selcx.infcx.shallow_resolve(obligation.predicate.self_ty()); - let sig = fn_type.fn_sig(selcx.tcx()); + let sig = fn_type.fn_sig(tcx); let Normalized { value: sig, obligations } = normalize_with_depth( selcx, obligation.param_env, @@ -2337,9 +2338,24 @@ fn confirm_fn_pointer_candidate<'cx, 'tcx>( sig, ); - confirm_callable_candidate(selcx, obligation, sig, util::TupleArgumentsFlag::Yes) - .with_addl_obligations(nested) - .with_addl_obligations(obligations) + let host_effect_param = match *fn_type.kind() { + ty::FnDef(def_id, args) => tcx + .generics_of(def_id) + .host_effect_index + .map_or(tcx.consts.true_, |idx| args.const_at(idx)), + ty::FnPtr(_) => tcx.consts.true_, + _ => unreachable!("only expected FnPtr or FnDef in `confirm_fn_pointer_candidate`"), + }; + + confirm_callable_candidate( + selcx, + obligation, + sig, + util::TupleArgumentsFlag::Yes, + host_effect_param, + ) + .with_addl_obligations(nested) + .with_addl_obligations(obligations) } fn confirm_closure_candidate<'cx, 'tcx>( @@ -2362,9 +2378,16 @@ fn confirm_closure_candidate<'cx, 'tcx>( debug!(?obligation, ?closure_sig, ?obligations, "confirm_closure_candidate"); - confirm_callable_candidate(selcx, obligation, closure_sig, util::TupleArgumentsFlag::No) - .with_addl_obligations(nested) - .with_addl_obligations(obligations) + confirm_callable_candidate( + selcx, + obligation, + closure_sig, + util::TupleArgumentsFlag::No, + // FIXME(effects): This doesn't handle const closures correctly! + selcx.tcx().consts.true_, + ) + .with_addl_obligations(nested) + .with_addl_obligations(obligations) } fn confirm_callable_candidate<'cx, 'tcx>( @@ -2372,6 +2395,7 @@ fn confirm_callable_candidate<'cx, 'tcx>( obligation: &ProjectionTyObligation<'tcx>, fn_sig: ty::PolyFnSig<'tcx>, flag: util::TupleArgumentsFlag, + fn_host_effect: ty::Const<'tcx>, ) -> Progress<'tcx> { let tcx = selcx.tcx(); @@ -2386,6 +2410,7 @@ fn confirm_callable_candidate<'cx, 'tcx>( obligation.predicate.self_ty(), fn_sig, flag, + fn_host_effect, ) .map_bound(|(trait_ref, ret_type)| ty::ProjectionPredicate { projection_ty: ty::AliasTy::new(tcx, fn_once_output_def_id, trait_ref.args), diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs index cd7fd028a46aa..73e06b8408562 100644 --- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs +++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs @@ -355,17 +355,23 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // Provide an impl, but only for suitable `fn` pointers. ty::FnPtr(sig) => { if sig.is_fn_trait_compatible() { - candidates.vec.push(FnPointerCandidate { is_const: false }); + candidates + .vec + .push(FnPointerCandidate { fn_host_effect: self.tcx().consts.true_ }); } } // Provide an impl for suitable functions, rejecting `#[target_feature]` functions (RFC 2396). - ty::FnDef(def_id, _) => { - if self.tcx().fn_sig(def_id).skip_binder().is_fn_trait_compatible() - && self.tcx().codegen_fn_attrs(def_id).target_features.is_empty() + ty::FnDef(def_id, args) => { + let tcx = self.tcx(); + if tcx.fn_sig(def_id).skip_binder().is_fn_trait_compatible() + && tcx.codegen_fn_attrs(def_id).target_features.is_empty() { - candidates - .vec - .push(FnPointerCandidate { is_const: self.tcx().is_const_fn(def_id) }); + candidates.vec.push(FnPointerCandidate { + fn_host_effect: tcx + .generics_of(def_id) + .host_effect_index + .map_or(tcx.consts.true_, |idx| args.const_at(idx)), + }); } } _ => {} diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index bcaf6aff66b50..ce3fc2185ba24 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -103,8 +103,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ImplSource::Builtin(BuiltinImplSource::Misc, vtable_iterator) } - FnPointerCandidate { is_const } => { - let data = self.confirm_fn_pointer_candidate(obligation, is_const)?; + FnPointerCandidate { fn_host_effect } => { + let data = self.confirm_fn_pointer_candidate(obligation, fn_host_effect)?; ImplSource::Builtin(BuiltinImplSource::Misc, data) } @@ -653,8 +653,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { fn confirm_fn_pointer_candidate( &mut self, obligation: &PolyTraitObligation<'tcx>, - // FIXME(effects) - _is_const: bool, + fn_host_effect: ty::Const<'tcx>, ) -> Result>, SelectionError<'tcx>> { debug!(?obligation, "confirm_fn_pointer_candidate"); @@ -675,6 +674,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { self_ty, sig, util::TupleArgumentsFlag::Yes, + fn_host_effect, ) .map_bound(|(trait_ref, _)| trait_ref); @@ -860,7 +860,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { bug!("closure candidate for non-closure {:?}", obligation); }; - let trait_ref = self.closure_trait_ref_unnormalized(obligation, args); + let trait_ref = + self.closure_trait_ref_unnormalized(obligation, args, self.tcx().consts.true_); let nested = self.confirm_poly_trait_refs(obligation, trait_ref)?; debug!(?closure_def_id, ?trait_ref, ?nested, "confirm closure candidate obligations"); diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index 9886e33ca3b5a..c7a30535caa18 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -1865,7 +1865,9 @@ impl<'tcx> SelectionContext<'_, 'tcx> { } // Drop otherwise equivalent non-const fn pointer candidates - (FnPointerCandidate { .. }, FnPointerCandidate { is_const: false }) => DropVictim::Yes, + (FnPointerCandidate { .. }, FnPointerCandidate { fn_host_effect }) => { + DropVictim::drop_if(*fn_host_effect == self.tcx().consts.true_) + } ( ParamCandidate(ref other_cand), @@ -2660,6 +2662,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { &mut self, obligation: &PolyTraitObligation<'tcx>, args: GenericArgsRef<'tcx>, + fn_host_effect: ty::Const<'tcx>, ) -> ty::PolyTraitRef<'tcx> { let closure_sig = args.as_closure().sig(); @@ -2680,6 +2683,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { self_ty, closure_sig, util::TupleArgumentsFlag::No, + fn_host_effect, ) .map_bound(|(trait_ref, _)| trait_ref) } diff --git a/compiler/rustc_trait_selection/src/traits/util.rs b/compiler/rustc_trait_selection/src/traits/util.rs index 575010ff46d85..19eae93df9c87 100644 --- a/compiler/rustc_trait_selection/src/traits/util.rs +++ b/compiler/rustc_trait_selection/src/traits/util.rs @@ -264,13 +264,26 @@ pub fn closure_trait_ref_and_return_type<'tcx>( self_ty: Ty<'tcx>, sig: ty::PolyFnSig<'tcx>, tuple_arguments: TupleArgumentsFlag, + fn_host_effect: ty::Const<'tcx>, ) -> ty::Binder<'tcx, (ty::TraitRef<'tcx>, Ty<'tcx>)> { assert!(!self_ty.has_escaping_bound_vars()); let arguments_tuple = match tuple_arguments { TupleArgumentsFlag::No => sig.skip_binder().inputs()[0], TupleArgumentsFlag::Yes => Ty::new_tup(tcx, sig.skip_binder().inputs()), }; - let trait_ref = ty::TraitRef::new(tcx, fn_trait_def_id, [self_ty, arguments_tuple]); + let trait_ref = if tcx.generics_of(fn_trait_def_id).host_effect_index.is_some() { + ty::TraitRef::new( + tcx, + fn_trait_def_id, + [ + ty::GenericArg::from(self_ty), + ty::GenericArg::from(arguments_tuple), + ty::GenericArg::from(fn_host_effect), + ], + ) + } else { + ty::TraitRef::new(tcx, fn_trait_def_id, [self_ty, arguments_tuple]) + }; sig.map_bound(|sig| (trait_ref, sig.output())) } diff --git a/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/minicore.rs b/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/minicore.rs index 2a2e8cec3f084..dc0e00bae4ef5 100644 --- a/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/minicore.rs +++ b/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/minicore.rs @@ -1,12 +1,13 @@ // check-pass #![crate_type = "lib"] -#![feature(no_core, lang_items, unboxed_closures, auto_traits, intrinsics, rustc_attrs)] +#![feature(no_core, lang_items, unboxed_closures, auto_traits, intrinsics, rustc_attrs, staged_api)] #![feature(fundamental)] #![feature(const_trait_impl, effects, const_mut_refs)] #![allow(internal_features)] #![no_std] #![no_core] +#![stable(feature = "minicore", since = "1.0.0")] #[lang = "sized"] trait Sized {} @@ -82,6 +83,7 @@ trait FnMut: ~const FnOnce { #[lang = "fn_once"] #[rustc_paren_sugar] trait FnOnce { + #[lang = "fn_once_output"] type Output; extern "rust-call" fn call_once(self, args: Args) -> Self::Output; @@ -93,7 +95,7 @@ struct ConstFnMutClosure { } #[lang = "tuple_trait"] -pub trait Tuple {} +trait Tuple {} macro_rules! impl_fn_mut_tuple { ($($var:ident)*) => { @@ -509,3 +511,12 @@ trait StructuralPartialEq {} trait StructuralEq {} const fn drop(_: T) {} + +extern "rust-intrinsic" { + #[rustc_const_stable(feature = "const_eval_select", since = "1.0.0")] + fn const_eval_select( + arg: ARG, + called_in_const: F, + called_at_rt: G, + ) -> RET; +}