diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src/collect')
6 files changed, 555 insertions, 607 deletions
diff --git a/compiler/rustc_hir_analysis/src/collect/generics_of.rs b/compiler/rustc_hir_analysis/src/collect/generics_of.rs index 119933697..ed60998ec 100644 --- a/compiler/rustc_hir_analysis/src/collect/generics_of.rs +++ b/compiler/rustc_hir_analysis/src/collect/generics_of.rs @@ -51,7 +51,15 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics { // of a const parameter type, e.g. `struct Foo<const N: usize, const M: [u8; N]>` is not allowed. None } else if tcx.lazy_normalization() { - if let Some(param_id) = tcx.hir().opt_const_param_default_param_def_id(hir_id) { + let parent_node = tcx.hir().get_parent(hir_id); + if let Node::Variant(Variant { disr_expr: Some(constant), .. }) = parent_node + && constant.hir_id == hir_id + { + // enum variant discriminants are not allowed to use any kind of generics + None + } else if let Some(param_id) = + tcx.hir().opt_const_param_default_param_def_id(hir_id) + { // If the def_id we are calling generics_of on is an anon ct default i.e: // // struct Foo<const N: usize = { .. }>; @@ -94,15 +102,15 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics { has_self: generics.has_self, has_late_bound_regions: generics.has_late_bound_regions, }; + } else { + // HACK(eddyb) this provides the correct generics when + // `feature(generic_const_expressions)` is enabled, so that const expressions + // used with const generics, e.g. `Foo<{N+1}>`, can work at all. + // + // Note that we do not supply the parent generics when using + // `min_const_generics`. + Some(parent_def_id.to_def_id()) } - - // HACK(eddyb) this provides the correct generics when - // `feature(generic_const_expressions)` is enabled, so that const expressions - // used with const generics, e.g. `Foo<{N+1}>`, can work at all. - // - // Note that we do not supply the parent generics when using - // `min_const_generics`. - Some(parent_def_id.to_def_id()) } else { let parent_node = tcx.hir().get_parent(hir_id); match parent_node { @@ -115,11 +123,6 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics { { Some(parent_def_id.to_def_id()) } - Node::Variant(Variant { disr_expr: Some(constant), .. }) - if constant.hir_id == hir_id => - { - Some(parent_def_id.to_def_id()) - } Node::Expr(&Expr { kind: ExprKind::ConstBlock(_), .. }) => { Some(tcx.typeck_root_def_id(def_id.to_def_id())) } @@ -156,7 +159,10 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics { } Some(fn_def_id.to_def_id()) } - ItemKind::OpaqueTy(hir::OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => { + ItemKind::OpaqueTy(hir::OpaqueTy { + origin: hir::OpaqueTyOrigin::TyAlias { .. }, + .. + }) => { let parent_id = tcx.hir().get_parent_item(hir_id); assert_ne!(parent_id, hir::CRATE_OWNER_ID); debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id); diff --git a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs index 2e56d2463..948b903e5 100644 --- a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs +++ b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs @@ -1,5 +1,5 @@ use super::ItemCtxt; -use crate::astconv::AstConv; +use crate::astconv::{AstConv, OnlySelfBounds}; use rustc_hir as hir; use rustc_infer::traits::util; use rustc_middle::ty::subst::InternalSubsts; @@ -26,7 +26,7 @@ fn associated_type_bounds<'tcx>( ); let icx = ItemCtxt::new(tcx, assoc_item_def_id); - let mut bounds = icx.astconv().compute_bounds(item_ty, ast_bounds); + let mut bounds = icx.astconv().compute_bounds(item_ty, ast_bounds, OnlySelfBounds(false)); // Associated types are implicitly sized unless a `?Sized` bound is found icx.astconv().add_implicitly_sized(&mut bounds, item_ty, ast_bounds, None, span); @@ -67,7 +67,7 @@ fn opaque_type_bounds<'tcx>( ) -> &'tcx [(ty::Predicate<'tcx>, Span)] { ty::print::with_no_queries!({ let icx = ItemCtxt::new(tcx, opaque_def_id); - let mut bounds = icx.astconv().compute_bounds(item_ty, ast_bounds); + let mut bounds = icx.astconv().compute_bounds(item_ty, ast_bounds, OnlySelfBounds(false)); // Opaque types are implicitly sized unless a `?Sized` bound is found icx.astconv().add_implicitly_sized(&mut bounds, item_ty, ast_bounds, None, span); debug!(?bounds); @@ -79,14 +79,14 @@ fn opaque_type_bounds<'tcx>( pub(super) fn explicit_item_bounds( tcx: TyCtxt<'_>, def_id: LocalDefId, -) -> &'_ [(ty::Predicate<'_>, Span)] { +) -> ty::EarlyBinder<&'_ [(ty::Predicate<'_>, Span)]> { match tcx.opt_rpitit_info(def_id.to_def_id()) { // RPITIT's bounds are the same as opaque type bounds, but with // a projection self type. Some(ty::ImplTraitInTraitData::Trait { opaque_def_id, .. }) => { let item = tcx.hir().get_by_def_id(opaque_def_id.expect_local()).expect_item(); let opaque_ty = item.expect_opaque_ty(); - return opaque_type_bounds( + return ty::EarlyBinder(opaque_type_bounds( tcx, opaque_def_id.expect_local(), opaque_ty.bounds, @@ -95,7 +95,7 @@ pub(super) fn explicit_item_bounds( ty::InternalSubsts::identity_for_item(tcx, def_id), ), item.span, - ); + )); } // These should have been fed! Some(ty::ImplTraitInTraitData::Impl { .. }) => unreachable!(), @@ -103,7 +103,7 @@ pub(super) fn explicit_item_bounds( } let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); - match tcx.hir().get(hir_id) { + let bounds = match tcx.hir().get(hir_id) { hir::Node::TraitItem(hir::TraitItem { kind: hir::TraitItemKind::Type(bounds, _), span, @@ -123,16 +123,18 @@ pub(super) fn explicit_item_bounds( opaque_type_bounds(tcx, def_id, bounds, item_ty, *span) } _ => bug!("item_bounds called on {:?}", def_id), - } + }; + ty::EarlyBinder(bounds) } pub(super) fn item_bounds( tcx: TyCtxt<'_>, def_id: DefId, ) -> ty::EarlyBinder<&'_ ty::List<ty::Predicate<'_>>> { - let bounds = tcx.mk_predicates_from_iter(util::elaborate( - tcx, - tcx.explicit_item_bounds(def_id).iter().map(|&(bound, _span)| bound), - )); - ty::EarlyBinder(bounds) + tcx.explicit_item_bounds(def_id).map_bound(|bounds| { + tcx.mk_predicates_from_iter(util::elaborate( + tcx, + bounds.iter().map(|&(bound, _span)| bound), + )) + }) } diff --git a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs index 9358ed612..e5b5dae55 100644 --- a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs +++ b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs @@ -1,4 +1,4 @@ -use crate::astconv::AstConv; +use crate::astconv::{AstConv, OnlySelfBounds}; use crate::bounds::Bounds; use crate::collect::ItemCtxt; use crate::constrained_generic_params as cgp; @@ -14,9 +14,6 @@ use rustc_middle::ty::{GenericPredicates, ToPredicate}; use rustc_span::symbol::{sym, Ident}; use rustc_span::{Span, DUMMY_SP}; -#[derive(Debug)] -struct OnlySelfBounds(bool); - /// Returns a list of all type predicates (explicit and implicit) for the definition with /// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus /// `Self: Trait` predicates for traits. @@ -99,8 +96,9 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen | ItemKind::Struct(_, generics) | ItemKind::Union(_, generics) => generics, - ItemKind::Trait(_, _, generics, ..) | ItemKind::TraitAlias(generics, _) => { - is_trait = Some(ty::TraitRef::identity(tcx, def_id.to_def_id())); + ItemKind::Trait(_, _, generics, self_bounds, ..) + | ItemKind::TraitAlias(generics, self_bounds) => { + is_trait = Some(self_bounds); generics } ItemKind::OpaqueTy(OpaqueTy { generics, .. }) => generics, @@ -122,10 +120,14 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen // Below we'll consider the bounds on the type parameters (including `Self`) // and the explicit where-clauses, but to get the full set of predicates - // on a trait we need to add in the supertrait bounds and bounds found on - // associated types. - if let Some(_trait_ref) = is_trait { - predicates.extend(tcx.implied_predicates_of(def_id).predicates.iter().cloned()); + // on a trait we must also consider the bounds that follow the trait's name, + // like `trait Foo: A + B + C`. + if let Some(self_bounds) = is_trait { + predicates.extend( + icx.astconv() + .compute_bounds(tcx.types.self_param, self_bounds, OnlySelfBounds(false)) + .predicates(), + ); } // In default impls, we can assume that the self type implements @@ -225,7 +227,13 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen } let mut bounds = Bounds::default(); - icx.astconv().add_bounds(ty, bound_pred.bounds.iter(), &mut bounds, bound_vars); + icx.astconv().add_bounds( + ty, + bound_pred.bounds.iter(), + &mut bounds, + bound_vars, + OnlySelfBounds(false), + ); predicates.extend(bounds.predicates()); } @@ -419,6 +427,8 @@ pub(super) fn explicit_predicates_of<'tcx>( // supertrait). if let ty::Alias(ty::Projection, projection) = ty.kind() { projection.substs == trait_identity_substs + // FIXME(return_type_notation): This check should be more robust + && !tcx.is_impl_trait_in_trait(projection.def_id) && tcx.associated_item(projection.def_id).container_id(tcx) == def_id.to_def_id() } else { @@ -557,7 +567,7 @@ pub(super) fn super_predicates_of( implied_predicates_with_filter(tcx, trait_def_id.to_def_id(), PredicateFilter::SelfOnly) } -pub(super) fn super_predicates_that_define_assoc_type( +pub(super) fn super_predicates_that_define_assoc_item( tcx: TyCtxt<'_>, (trait_def_id, assoc_name): (DefId, Ident), ) -> ty::GenericPredicates<'_> { @@ -608,7 +618,7 @@ pub(super) fn implied_predicates_with_filter( let (superbounds, where_bounds_that_match) = match filter { PredicateFilter::All => ( // Convert the bounds that follow the colon (or equal in trait aliases) - icx.astconv().compute_bounds(self_param_ty, bounds), + icx.astconv().compute_bounds(self_param_ty, bounds, OnlySelfBounds(false)), // Also include all where clause bounds icx.type_parameter_bounds_in_generics( generics, @@ -620,7 +630,7 @@ pub(super) fn implied_predicates_with_filter( ), PredicateFilter::SelfOnly => ( // Convert the bounds that follow the colon (or equal in trait aliases) - icx.astconv().compute_bounds(self_param_ty, bounds), + icx.astconv().compute_bounds(self_param_ty, bounds, OnlySelfBounds(true)), // Include where clause bounds for `Self` icx.type_parameter_bounds_in_generics( generics, @@ -632,7 +642,7 @@ pub(super) fn implied_predicates_with_filter( ), PredicateFilter::SelfThatDefines(assoc_name) => ( // Convert the bounds that follow the colon (or equal) that reference the associated name - icx.astconv().compute_bounds_that_match_assoc_type(self_param_ty, bounds, assoc_name), + icx.astconv().compute_bounds_that_match_assoc_item(self_param_ty, bounds, assoc_name), // Include where clause bounds for `Self` that reference the associated name icx.type_parameter_bounds_in_generics( generics, @@ -645,19 +655,19 @@ pub(super) fn implied_predicates_with_filter( }; // Combine the two lists to form the complete set of superbounds: - let implied_bounds = &*tcx - .arena - .alloc_from_iter(superbounds.predicates().into_iter().chain(where_bounds_that_match)); + let implied_bounds = + &*tcx.arena.alloc_from_iter(superbounds.predicates().chain(where_bounds_that_match)); debug!(?implied_bounds); - // Now require that immediate supertraits are converted, - // which will, in turn, reach indirect supertraits. + // Now require that immediate supertraits are converted, which will, in + // turn, reach indirect supertraits, so we detect cycles now instead of + // overflowing during elaboration. if matches!(filter, PredicateFilter::SelfOnly) { - // Now require that immediate supertraits are converted, - // which will, in turn, reach indirect supertraits. for &(pred, span) in implied_bounds { debug!("superbound: {:?}", pred); - if let ty::PredicateKind::Clause(ty::Clause::Trait(bound)) = pred.kind().skip_binder() { + if let ty::PredicateKind::Clause(ty::Clause::Trait(bound)) = pred.kind().skip_binder() + && bound.polarity == ty::ImplPolarity::Positive + { tcx.at(span).super_predicates_of(bound.def_id()); } } @@ -713,7 +723,7 @@ pub(super) fn type_param_predicates( | ItemKind::TyAlias(_, generics) | ItemKind::OpaqueTy(OpaqueTy { generics, - origin: hir::OpaqueTyOrigin::TyAlias, + origin: hir::OpaqueTyOrigin::TyAlias { .. }, .. }) | ItemKind::Enum(_, generics) @@ -775,32 +785,35 @@ impl<'tcx> ItemCtxt<'tcx> { only_self_bounds: OnlySelfBounds, assoc_name: Option<Ident>, ) -> Vec<(ty::Predicate<'tcx>, Span)> { - ast_generics - .predicates - .iter() - .filter_map(|wp| match wp { - hir::WherePredicate::BoundPredicate(bp) => Some(bp), - _ => None, - }) - .flat_map(|bp| { - let bt = if bp.is_param_bound(param_def_id.to_def_id()) { - Some(ty) - } else if !only_self_bounds.0 { - Some(self.to_ty(bp.bounded_ty)) - } else { - None - }; - let bvars = self.tcx.late_bound_vars(bp.hir_id); - - bp.bounds.iter().filter_map(move |b| bt.map(|bt| (bt, b, bvars))).filter( - |(_, b, _)| match assoc_name { - Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name), - None => true, - }, - ) - }) - .flat_map(|(bt, b, bvars)| predicates_from_bound(self, bt, b, bvars)) - .collect() + let mut bounds = Bounds::default(); + + for predicate in ast_generics.predicates { + let hir::WherePredicate::BoundPredicate(predicate) = predicate else { + continue; + }; + + let bound_ty = if predicate.is_param_bound(param_def_id.to_def_id()) { + ty + } else if !only_self_bounds.0 { + self.to_ty(predicate.bounded_ty) + } else { + continue; + }; + + let bound_vars = self.tcx.late_bound_vars(predicate.hir_id); + self.astconv().add_bounds( + bound_ty, + predicate.bounds.iter().filter(|bound| { + assoc_name + .map_or(true, |assoc_name| self.bound_defines_assoc_item(bound, assoc_name)) + }), + &mut bounds, + bound_vars, + only_self_bounds, + ); + } + + bounds.predicates().collect() } #[instrument(level = "trace", skip(self))] @@ -809,7 +822,7 @@ impl<'tcx> ItemCtxt<'tcx> { hir::GenericBound::Trait(poly_trait_ref, _) => { let trait_ref = &poly_trait_ref.trait_ref; if let Some(trait_did) = trait_ref.trait_def_id() { - self.tcx.trait_may_define_assoc_type(trait_did, assoc_name) + self.tcx.trait_may_define_assoc_item(trait_did, assoc_name) } else { false } @@ -818,19 +831,3 @@ impl<'tcx> ItemCtxt<'tcx> { } } } - -/// Converts a specific `GenericBound` from the AST into a set of -/// predicates that apply to the self type. A vector is returned -/// because this can be anywhere from zero predicates (`T: ?Sized` adds no -/// predicates) to one (`T: Foo`) to many (`T: Bar<X = i32>` adds `T: Bar` -/// and `<T as Bar>::X == i32`). -fn predicates_from_bound<'tcx>( - astconv: &dyn AstConv<'tcx>, - param_ty: Ty<'tcx>, - bound: &'tcx hir::GenericBound<'tcx>, - bound_vars: &'tcx ty::List<ty::BoundVariableKind>, -) -> Vec<(ty::Predicate<'tcx>, Span)> { - let mut bounds = Bounds::default(); - astconv.add_bounds(param_ty, [bound].into_iter(), &mut bounds, bound_vars); - bounds.predicates().collect() -} diff --git a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs index e758fe95d..794812a5c 100644 --- a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs +++ b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs @@ -17,6 +17,7 @@ use rustc_hir::{GenericArg, GenericParam, GenericParamKind, HirIdMap, LifetimeNa use rustc_middle::bug; use rustc_middle::hir::nested_filter; use rustc_middle::middle::resolve_bound_vars::*; +use rustc_middle::query::Providers; use rustc_middle::ty::{self, TyCtxt, TypeSuperVisitable, TypeVisitor}; use rustc_session::lint; use rustc_span::def_id::DefId; @@ -232,8 +233,8 @@ impl<'a> fmt::Debug for TruncatedScopeDebug<'a> { type ScopeRef<'a> = &'a Scope<'a>; -pub(crate) fn provide(providers: &mut ty::query::Providers) { - *providers = ty::query::Providers { +pub(crate) fn provide(providers: &mut Providers) { + *providers = Providers { resolve_bound_vars, named_variable_map: |tcx, id| tcx.resolve_bound_vars(id).defs.get(&id), @@ -455,13 +456,9 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> { .collect::<Vec<_>>(); if !infer_spans.is_empty() { - self.tcx.sess - .struct_span_err( - infer_spans, - "implicit types in closure signatures are forbidden when `for<...>` is present", - ) - .span_label(for_sp, "`for<...>` is here") - .emit(); + self.tcx + .sess + .emit_err(errors::ClosureImplicitHrtb { spans: infer_spans, for_sp }); } } @@ -530,7 +527,8 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> { }); } hir::ItemKind::OpaqueTy(hir::OpaqueTy { - origin: hir::OpaqueTyOrigin::TyAlias, .. + origin: hir::OpaqueTyOrigin::TyAlias { .. }, + .. }) => { // Opaque types are visited when we visit the // `TyKind::OpaqueDef`, so that they have the lifetimes from @@ -711,7 +709,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> { let opaque_ty = self.tcx.hir().item(item_id); match &opaque_ty.kind { hir::ItemKind::OpaqueTy(hir::OpaqueTy { - origin: hir::OpaqueTyOrigin::TyAlias, + origin: hir::OpaqueTyOrigin::TyAlias { .. }, .. }) => { intravisit::walk_ty(self, ty); @@ -991,7 +989,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> { lifetime.ident ), |lint| { - let help = &format!( + let help = format!( "you can use the `'static` lifetime directly, in place of `{}`", lifetime.ident, ); @@ -1333,7 +1331,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> { // We may fail to resolve higher-ranked lifetimes that are mentioned by APIT. // AST-based resolution does not care for impl-trait desugaring, which are the - // responibility of lowering. This may create a mismatch between the resolution + // responsibility of lowering. This may create a mismatch between the resolution // AST found (`region_def_id`) which points to HRTB, and what HIR allows. // ``` // fn foo(x: impl for<'a> Trait<'a, Assoc = impl Copy + 'a>) {} @@ -1369,7 +1367,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> { self.tcx.sess.delay_span_bug( lifetime_ref.ident.span, - &format!("Could not resolve {:?} in scope {:#?}", lifetime_ref, self.scope,), + format!("Could not resolve {:?} in scope {:#?}", lifetime_ref, self.scope,), ); } @@ -1656,17 +1654,16 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> { if binding.gen_args.parenthesized == hir::GenericArgsParentheses::ReturnTypeNotation { let bound_vars = if let Some(type_def_id) = type_def_id && self.tcx.def_kind(type_def_id) == DefKind::Trait - // FIXME(return_type_notation): We could bound supertrait methods. - && let Some(assoc_fn) = self - .tcx - .associated_items(type_def_id) - .find_by_name_and_kind(self.tcx, binding.ident, ty::AssocKind::Fn, type_def_id) + && let Some((mut bound_vars, assoc_fn)) = + BoundVarContext::supertrait_hrtb_vars( + self.tcx, + type_def_id, + binding.ident, + ty::AssocKind::Fn, + ) { - self.tcx - .generics_of(assoc_fn.def_id) - .params - .iter() - .map(|param| match param.kind { + bound_vars.extend(self.tcx.generics_of(assoc_fn.def_id).params.iter().map( + |param| match param.kind { ty::GenericParamDefKind::Lifetime => ty::BoundVariableKind::Region( ty::BoundRegionKind::BrNamed(param.def_id, param.name), ), @@ -1674,9 +1671,11 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> { ty::BoundTyKind::Param(param.def_id, param.name), ), ty::GenericParamDefKind::Const { .. } => ty::BoundVariableKind::Const, - }) - .chain(self.tcx.fn_sig(assoc_fn.def_id).subst_identity().bound_vars()) - .collect() + }, + )); + bound_vars + .extend(self.tcx.fn_sig(assoc_fn.def_id).subst_identity().bound_vars()); + bound_vars } else { self.tcx.sess.delay_span_bug( binding.ident.span, @@ -1693,8 +1692,13 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> { }); }); } else if let Some(type_def_id) = type_def_id { - let bound_vars = - BoundVarContext::supertrait_hrtb_vars(self.tcx, type_def_id, binding.ident); + let bound_vars = BoundVarContext::supertrait_hrtb_vars( + self.tcx, + type_def_id, + binding.ident, + ty::AssocKind::Type, + ) + .map(|(bound_vars, _)| bound_vars); self.with(scope, |this| { let scope = Scope::Supertrait { bound_vars: bound_vars.unwrap_or_default(), @@ -1724,11 +1728,15 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> { tcx: TyCtxt<'tcx>, def_id: DefId, assoc_name: Ident, - ) -> Option<Vec<ty::BoundVariableKind>> { - let trait_defines_associated_type_named = |trait_def_id: DefId| { - tcx.associated_items(trait_def_id) - .find_by_name_and_kind(tcx, assoc_name, ty::AssocKind::Type, trait_def_id) - .is_some() + assoc_kind: ty::AssocKind, + ) -> Option<(Vec<ty::BoundVariableKind>, &'tcx ty::AssocItem)> { + let trait_defines_associated_item_named = |trait_def_id: DefId| { + tcx.associated_items(trait_def_id).find_by_name_and_kind( + tcx, + assoc_name, + assoc_kind, + trait_def_id, + ) }; use smallvec::{smallvec, SmallVec}; @@ -1746,10 +1754,10 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> { _ => break None, } - if trait_defines_associated_type_named(def_id) { - break Some(bound_vars.into_iter().collect()); + if let Some(assoc_item) = trait_defines_associated_item_named(def_id) { + break Some((bound_vars.into_iter().collect(), assoc_item)); } - let predicates = tcx.super_predicates_that_define_assoc_type((def_id, assoc_name)); + let predicates = tcx.super_predicates_that_define_assoc_item((def_id, assoc_name)); let obligations = predicates.predicates.iter().filter_map(|&(pred, _)| { let bound_predicate = pred.kind(); match bound_predicate.skip_binder() { @@ -1917,7 +1925,7 @@ fn is_late_bound_map( /// handles cycle detection as we go through the query system. /// /// This is necessary in the first place for the following case: - /// ``` + /// ```rust,ignore (pseudo-Rust) /// type Alias<'a, T> = <T as Trait<'a>>::Assoc; /// fn foo<'a>(_: Alias<'a, ()>) -> Alias<'a, ()> { ... } /// ``` @@ -1942,7 +1950,7 @@ fn is_late_bound_map( ty::Param(param_ty) => { self.arg_is_constrained[param_ty.index as usize] = true; } - ty::Alias(ty::Projection, _) => return ControlFlow::Continue(()), + ty::Alias(ty::Projection | ty::Inherent, _) => return ControlFlow::Continue(()), _ => (), } t.super_visit_with(self) diff --git a/compiler/rustc_hir_analysis/src/collect/type_of.rs b/compiler/rustc_hir_analysis/src/collect/type_of.rs index c173bd913..8e082d3c5 100644 --- a/compiler/rustc_hir_analysis/src/collect/type_of.rs +++ b/compiler/rustc_hir_analysis/src/collect/type_of.rs @@ -1,10 +1,7 @@ use rustc_errors::{Applicability, StashKey}; use rustc_hir as hir; -use rustc_hir::def_id::{DefId, LocalDefId}; -use rustc_hir::intravisit; -use rustc_hir::intravisit::Visitor; -use rustc_hir::{HirId, Node}; -use rustc_middle::hir::nested_filter; +use rustc_hir::def_id::LocalDefId; +use rustc_hir::HirId; use rustc_middle::ty::print::with_forced_trimmed_paths; use rustc_middle::ty::subst::InternalSubsts; use rustc_middle::ty::util::IntTypeExt; @@ -14,24 +11,84 @@ use rustc_span::{Span, DUMMY_SP}; use super::ItemCtxt; use super::{bad_placeholder, is_suggestable_infer_ty}; -use crate::errors::UnconstrainedOpaqueType; -/// Computes the relevant generic parameter for a potential generic const argument. -/// -/// This should be called using the query `tcx.opt_const_param_of`. -pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<DefId> { +mod opaque; + +fn anon_const_type_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Ty<'tcx> { use hir::*; let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); - match tcx.hir().get(hir_id) { - Node::AnonConst(_) => (), - _ => return None, - }; + let Node::AnonConst(_) = tcx.hir().get(hir_id) else { panic!() }; let parent_node_id = tcx.hir().parent_id(hir_id); let parent_node = tcx.hir().get(parent_node_id); let (generics, arg_idx) = match parent_node { + // Easy case: arrays repeat expressions. + Node::Ty(&Ty { kind: TyKind::Array(_, ref constant), .. }) + | Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. }) + if constant.hir_id() == hir_id => + { + return tcx.types.usize + } + Node::Ty(&Ty { kind: TyKind::Typeof(ref e), .. }) if e.hir_id == hir_id => { + return tcx.typeck(def_id).node_type(e.hir_id) + } + Node::Expr(&Expr { kind: ExprKind::ConstBlock(ref anon_const), .. }) + if anon_const.hir_id == hir_id => + { + let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); + return substs.as_inline_const().ty() + } + Node::Expr(&Expr { kind: ExprKind::InlineAsm(asm), .. }) + | Node::Item(&Item { kind: ItemKind::GlobalAsm(asm), .. }) + if asm.operands.iter().any(|(op, _op_sp)| match op { + hir::InlineAsmOperand::Const { anon_const } + | hir::InlineAsmOperand::SymFn { anon_const } => anon_const.hir_id == hir_id, + _ => false, + }) => + { + return tcx.typeck(def_id).node_type(hir_id) + } + Node::Variant(Variant { disr_expr: Some(ref e), .. }) if e.hir_id == hir_id => { + return tcx + .adt_def(tcx.hir().get_parent_item(hir_id)) + .repr() + .discr_type() + .to_ty(tcx) + } + Node::GenericParam(&GenericParam { + def_id: param_def_id, + kind: GenericParamKind::Const { default: Some(ct), .. }, + .. + }) if ct.hir_id == hir_id => { + return tcx.type_of(param_def_id) + .no_bound_vars() + .expect("const parameter types cannot be generic") + } + + Node::TypeBinding(binding @ &TypeBinding { hir_id: binding_id, .. }) + if let Node::TraitRef(trait_ref) = tcx.hir().get( + tcx.hir().parent_id(binding_id) + ) => + { + let Some(trait_def_id) = trait_ref.trait_def_id() else { + return tcx.ty_error_with_message(tcx.def_span(def_id), "Could not find trait"); + }; + let assoc_items = tcx.associated_items(trait_def_id); + let assoc_item = assoc_items.find_by_name_and_kind( + tcx, binding.ident, ty::AssocKind::Const, def_id.to_def_id(), + ); + return if let Some(assoc_item) = assoc_item { + tcx.type_of(assoc_item.def_id) + .no_bound_vars() + .expect("const parameter types cannot be generic") + } else { + // FIXME(associated_const_equality): add a useful error message here. + tcx.ty_error_with_message(tcx.def_span(def_id), "Could not find associated const on trait") + } + } + // This match arm is for when the def_id appears in a GAT whose // path can't be resolved without typechecking e.g. // @@ -68,7 +125,7 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option< // the def_id that this query was called with. We filter to only type and const args here // as a precaution for if it's ever allowed to elide lifetimes in GAT's. It currently isn't // but it can't hurt to be safe ^^ - if let ty::Alias(ty::Projection, projection) = ty.kind() { + if let ty::Alias(ty::Projection | ty::Inherent, projection) = ty.kind() { let generics = tcx.generics_of(projection.def_id); let arg_index = segment @@ -86,11 +143,10 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option< (generics, arg_index) } else { // I dont think it's possible to reach this but I'm not 100% sure - BoxyUwU - tcx.sess.delay_span_bug( + return tcx.ty_error_with_message( tcx.def_span(def_id), "unexpected non-GAT usage of an anon const", ); - return None; } } Node::Expr(&Expr { @@ -103,7 +159,12 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option< // This may fail in case the method/path does not actually exist. // As there is no relevant param for `def_id`, we simply return // `None` here. - let type_dependent_def = tables.type_dependent_def_id(parent_node_id)?; + let Some(type_dependent_def) = tables.type_dependent_def_id(parent_node_id) else { + return tcx.ty_error_with_message( + tcx.def_span(def_id), + format!("unable to find type-dependent def for {:?}", parent_node_id), + ); + }; let idx = segment .args .and_then(|args| { @@ -140,19 +201,17 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option< if let Some(path) = get_path_containing_arg_in_pat(pat, hir_id) { path } else { - tcx.sess.delay_span_bug( + return tcx.ty_error_with_message( tcx.def_span(def_id), - &format!("unable to find const parent for {} in pat {:?}", hir_id, pat), + format!("unable to find const parent for {} in pat {:?}", hir_id, pat), ); - return None; } } _ => { - tcx.sess.delay_span_bug( + return tcx.ty_error_with_message( tcx.def_span(def_id), - &format!("unexpected const parent path {:?}", parent_node), + format!("unexpected const parent path {:?}", parent_node), ); - return None; } }; @@ -171,32 +230,34 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option< .position(|ct| ct.hir_id == hir_id) .map(|idx| (idx, seg))) }) else { - tcx.sess.delay_span_bug( + return tcx.ty_error_with_message( tcx.def_span(def_id), "no arg matching AnonConst in path", ); - return None; }; let generics = match tcx.res_generics_def_id(segment.res) { Some(def_id) => tcx.generics_of(def_id), None => { - tcx.sess.delay_span_bug( + return tcx.ty_error_with_message( tcx.def_span(def_id), - &format!("unexpected anon const res {:?} in path: {:?}", segment.res, path), + format!("unexpected anon const res {:?} in path: {:?}", segment.res, path), ); - return None; } }; (generics, arg_index) } - _ => return None, + + _ => return tcx.ty_error_with_message( + tcx.def_span(def_id), + format!("unexpected const parent in type_of(): {parent_node:?}"), + ), }; debug!(?parent_node); debug!(?generics, ?arg_idx); - generics + if let Some(param_def_id) = generics .params .iter() .filter(|param| param.kind.is_ty_or_const()) @@ -211,6 +272,14 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option< } _ => None, }) + { + tcx.type_of(param_def_id).no_bound_vars().expect("const parameter types cannot be generic") + } else { + return tcx.ty_error_with_message( + tcx.def_span(def_id), + format!("const generic parameter not found in {generics:?} at position {arg_idx:?}"), + ); + } } fn get_path_containing_arg_in_pat<'hir>( @@ -251,7 +320,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<Ty match tcx.collect_return_position_impl_trait_in_trait_tys(fn_def_id) { Ok(map) => { let assoc_item = tcx.associated_item(def_id); - return ty::EarlyBinder(map[&assoc_item.trait_item_def_id.unwrap()]); + return map[&assoc_item.trait_item_def_id.unwrap()]; } Err(_) => { return ty::EarlyBinder(tcx.ty_error_with_message( @@ -355,9 +424,10 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<Ty let substs = InternalSubsts::identity_for_item(tcx, def_id); tcx.mk_adt(def, substs) } - ItemKind::OpaqueTy(OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => { - find_opaque_ty_constraints_for_tait(tcx, def_id) - } + ItemKind::OpaqueTy(OpaqueTy { + origin: hir::OpaqueTyOrigin::TyAlias { .. }, + .. + }) => opaque::find_opaque_ty_constraints_for_tait(tcx, def_id), // Opaque types desugared from `impl Trait`. ItemKind::OpaqueTy(OpaqueTy { origin: @@ -371,7 +441,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<Ty "tried to get type of this RPITIT with no definition" ); } - find_opaque_ty_constraints_for_rpit(tcx, def_id, owner) + opaque::find_opaque_ty_constraints_for_rpit(tcx, def_id, owner) } ItemKind::Trait(..) | ItemKind::TraitAlias(..) @@ -415,143 +485,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<Ty tcx.typeck(def_id).node_type(hir_id) } - Node::AnonConst(_) if let Some(param) = tcx.opt_const_param_of(def_id) => { - // We defer to `type_of` of the corresponding parameter - // for generic arguments. - tcx.type_of(param).subst_identity() - } - - Node::AnonConst(_) => { - let parent_node = tcx.hir().get_parent(hir_id); - match parent_node { - Node::Ty(Ty { kind: TyKind::Array(_, constant), .. }) - | Node::Expr(Expr { kind: ExprKind::Repeat(_, constant), .. }) - if constant.hir_id() == hir_id => - { - tcx.types.usize - } - Node::Ty(Ty { kind: TyKind::Typeof(e), .. }) if e.hir_id == hir_id => { - tcx.typeck(def_id).node_type(e.hir_id) - } - - Node::Expr(Expr { kind: ExprKind::ConstBlock(anon_const), .. }) - if anon_const.hir_id == hir_id => - { - let substs = InternalSubsts::identity_for_item(tcx, def_id); - substs.as_inline_const().ty() - } - - Node::Expr(&Expr { kind: ExprKind::InlineAsm(asm), .. }) - | Node::Item(&Item { kind: ItemKind::GlobalAsm(asm), .. }) - if asm.operands.iter().any(|(op, _op_sp)| match op { - hir::InlineAsmOperand::Const { anon_const } - | hir::InlineAsmOperand::SymFn { anon_const } => { - anon_const.hir_id == hir_id - } - _ => false, - }) => - { - tcx.typeck(def_id).node_type(hir_id) - } - - Node::Variant(Variant { disr_expr: Some(e), .. }) if e.hir_id == hir_id => { - tcx.adt_def(tcx.hir().get_parent_item(hir_id)).repr().discr_type().to_ty(tcx) - } - - Node::TypeBinding(TypeBinding { - hir_id: binding_id, - kind: TypeBindingKind::Equality { term: Term::Const(e) }, - ident, - .. - }) if let Node::TraitRef(trait_ref) = tcx.hir().get_parent(*binding_id) - && e.hir_id == hir_id => - { - let Some(trait_def_id) = trait_ref.trait_def_id() else { - return ty::EarlyBinder(tcx.ty_error_with_message(DUMMY_SP, "Could not find trait")); - }; - let assoc_items = tcx.associated_items(trait_def_id); - let assoc_item = assoc_items.find_by_name_and_kind( - tcx, - *ident, - ty::AssocKind::Const, - def_id.to_def_id(), - ); - if let Some(assoc_item) = assoc_item { - tcx.type_of(assoc_item.def_id) - .no_bound_vars() - .expect("const parameter types cannot be generic") - } else { - // FIXME(associated_const_equality): add a useful error message here. - tcx.ty_error_with_message( - DUMMY_SP, - "Could not find associated const on trait", - ) - } - } - - Node::TypeBinding(TypeBinding { - hir_id: binding_id, - gen_args, - kind, - ident, - .. - }) if let Node::TraitRef(trait_ref) = tcx.hir().get_parent(*binding_id) - && let Some((idx, _)) = - gen_args.args.iter().enumerate().find(|(_, arg)| { - if let GenericArg::Const(ct) = arg { - ct.value.hir_id == hir_id - } else { - false - } - }) => - { - let Some(trait_def_id) = trait_ref.trait_def_id() else { - return ty::EarlyBinder(tcx.ty_error_with_message(DUMMY_SP, "Could not find trait")); - }; - let assoc_items = tcx.associated_items(trait_def_id); - let assoc_item = assoc_items.find_by_name_and_kind( - tcx, - *ident, - match kind { - // I think `<A: T>` type bindings requires that `A` is a type - TypeBindingKind::Constraint { .. } - | TypeBindingKind::Equality { term: Term::Ty(..) } => { - ty::AssocKind::Type - } - TypeBindingKind::Equality { term: Term::Const(..) } => { - ty::AssocKind::Const - } - }, - def_id.to_def_id(), - ); - if let Some(assoc_item) = assoc_item - && let param = &tcx.generics_of(assoc_item.def_id).params[idx] - && matches!(param.kind, ty::GenericParamDefKind::Const { .. }) - { - tcx.type_of(param.def_id) - .no_bound_vars() - .expect("const parameter types cannot be generic") - } else { - // FIXME(associated_const_equality): add a useful error message here. - tcx.ty_error_with_message( - DUMMY_SP, - "Could not find const param on associated item", - ) - } - } - - Node::GenericParam(&GenericParam { - def_id: param_def_id, - kind: GenericParamKind::Const { default: Some(ct), .. }, - .. - }) if ct.hir_id == hir_id => tcx.type_of(param_def_id).subst_identity(), - - x => tcx.ty_error_with_message( - DUMMY_SP, - &format!("unexpected const parent in type_of(): {x:?}"), - ), - } - } + Node::AnonConst(_) => anon_const_type_of(tcx, def_id), Node::GenericParam(param) => match ¶m.kind { GenericParamKind::Type { default: Some(ty), .. } @@ -566,303 +500,6 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<Ty ty::EarlyBinder(output) } -#[instrument(skip(tcx), level = "debug")] -/// Checks "defining uses" of opaque `impl Trait` types to ensure that they meet the restrictions -/// laid for "higher-order pattern unification". -/// This ensures that inference is tractable. -/// In particular, definitions of opaque types can only use other generics as arguments, -/// and they cannot repeat an argument. Example: -/// -/// ```ignore (illustrative) -/// type Foo<A, B> = impl Bar<A, B>; -/// -/// // Okay -- `Foo` is applied to two distinct, generic types. -/// fn a<T, U>() -> Foo<T, U> { .. } -/// -/// // Not okay -- `Foo` is applied to `T` twice. -/// fn b<T>() -> Foo<T, T> { .. } -/// -/// // Not okay -- `Foo` is applied to a non-generic type. -/// fn b<T>() -> Foo<T, u32> { .. } -/// ``` -/// -fn find_opaque_ty_constraints_for_tait(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Ty<'_> { - use rustc_hir::{Expr, ImplItem, Item, TraitItem}; - - struct ConstraintLocator<'tcx> { - tcx: TyCtxt<'tcx>, - - /// def_id of the opaque type whose defining uses are being checked - def_id: LocalDefId, - - /// as we walk the defining uses, we are checking that all of them - /// define the same hidden type. This variable is set to `Some` - /// with the first type that we find, and then later types are - /// checked against it (we also carry the span of that first - /// type). - found: Option<ty::OpaqueHiddenType<'tcx>>, - - /// In the presence of dead code, typeck may figure out a hidden type - /// while borrowck will not. We collect these cases here and check at - /// the end that we actually found a type that matches (modulo regions). - typeck_types: Vec<ty::OpaqueHiddenType<'tcx>>, - } - - impl ConstraintLocator<'_> { - #[instrument(skip(self), level = "debug")] - fn check(&mut self, item_def_id: LocalDefId) { - // Don't try to check items that cannot possibly constrain the type. - if !self.tcx.has_typeck_results(item_def_id) { - debug!("no constraint: no typeck results"); - return; - } - // Calling `mir_borrowck` can lead to cycle errors through - // const-checking, avoid calling it if we don't have to. - // ```rust - // type Foo = impl Fn() -> usize; // when computing type for this - // const fn bar() -> Foo { - // || 0usize - // } - // const BAZR: Foo = bar(); // we would mir-borrowck this, causing cycles - // // because we again need to reveal `Foo` so we can check whether the - // // constant does not contain interior mutability. - // ``` - let tables = self.tcx.typeck(item_def_id); - if let Some(guar) = tables.tainted_by_errors { - self.found = - Some(ty::OpaqueHiddenType { span: DUMMY_SP, ty: self.tcx.ty_error(guar) }); - return; - } - let Some(&typeck_hidden_ty) = tables.concrete_opaque_types.get(&self.def_id) else { - debug!("no constraints in typeck results"); - return; - }; - if self.typeck_types.iter().all(|prev| prev.ty != typeck_hidden_ty.ty) { - self.typeck_types.push(typeck_hidden_ty); - } - - // Use borrowck to get the type with unerased regions. - let concrete_opaque_types = &self.tcx.mir_borrowck(item_def_id).concrete_opaque_types; - debug!(?concrete_opaque_types); - if let Some(&concrete_type) = concrete_opaque_types.get(&self.def_id) { - debug!(?concrete_type, "found constraint"); - if let Some(prev) = &mut self.found { - if concrete_type.ty != prev.ty && !(concrete_type, prev.ty).references_error() { - let guar = prev.report_mismatch(&concrete_type, self.tcx); - prev.ty = self.tcx.ty_error(guar); - } - } else { - self.found = Some(concrete_type); - } - } - } - } - - impl<'tcx> intravisit::Visitor<'tcx> for ConstraintLocator<'tcx> { - type NestedFilter = nested_filter::All; - - fn nested_visit_map(&mut self) -> Self::Map { - self.tcx.hir() - } - fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) { - if let hir::ExprKind::Closure(closure) = ex.kind { - self.check(closure.def_id); - } - intravisit::walk_expr(self, ex); - } - fn visit_item(&mut self, it: &'tcx Item<'tcx>) { - trace!(?it.owner_id); - // The opaque type itself or its children are not within its reveal scope. - if it.owner_id.def_id != self.def_id { - self.check(it.owner_id.def_id); - intravisit::walk_item(self, it); - } - } - fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) { - trace!(?it.owner_id); - // The opaque type itself or its children are not within its reveal scope. - if it.owner_id.def_id != self.def_id { - self.check(it.owner_id.def_id); - intravisit::walk_impl_item(self, it); - } - } - fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) { - trace!(?it.owner_id); - self.check(it.owner_id.def_id); - intravisit::walk_trait_item(self, it); - } - } - - let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); - let scope = tcx.hir().get_defining_scope(hir_id); - let mut locator = ConstraintLocator { def_id, tcx, found: None, typeck_types: vec![] }; - - debug!(?scope); - - if scope == hir::CRATE_HIR_ID { - tcx.hir().walk_toplevel_module(&mut locator); - } else { - trace!("scope={:#?}", tcx.hir().get(scope)); - match tcx.hir().get(scope) { - // We explicitly call `visit_*` methods, instead of using `intravisit::walk_*` methods - // This allows our visitor to process the defining item itself, causing - // it to pick up any 'sibling' defining uses. - // - // For example, this code: - // ``` - // fn foo() { - // type Blah = impl Debug; - // let my_closure = || -> Blah { true }; - // } - // ``` - // - // requires us to explicitly process `foo()` in order - // to notice the defining usage of `Blah`. - Node::Item(it) => locator.visit_item(it), - Node::ImplItem(it) => locator.visit_impl_item(it), - Node::TraitItem(it) => locator.visit_trait_item(it), - other => bug!("{:?} is not a valid scope for an opaque type item", other), - } - } - - let Some(hidden) = locator.found else { - let reported = tcx.sess.emit_err(UnconstrainedOpaqueType { - span: tcx.def_span(def_id), - name: tcx.item_name(tcx.local_parent(def_id).to_def_id()), - what: match tcx.hir().get(scope) { - _ if scope == hir::CRATE_HIR_ID => "module", - Node::Item(hir::Item { kind: hir::ItemKind::Mod(_), .. }) => "module", - Node::Item(hir::Item { kind: hir::ItemKind::Impl(_), .. }) => "impl", - _ => "item", - }, - }); - return tcx.ty_error(reported); - }; - - // Only check against typeck if we didn't already error - if !hidden.ty.references_error() { - for concrete_type in locator.typeck_types { - if tcx.erase_regions(concrete_type.ty) != tcx.erase_regions(hidden.ty) - && !(concrete_type, hidden).references_error() - { - hidden.report_mismatch(&concrete_type, tcx); - } - } - } - - hidden.ty -} - -fn find_opaque_ty_constraints_for_rpit( - tcx: TyCtxt<'_>, - def_id: LocalDefId, - owner_def_id: LocalDefId, -) -> Ty<'_> { - use rustc_hir::{Expr, ImplItem, Item, TraitItem}; - - struct ConstraintChecker<'tcx> { - tcx: TyCtxt<'tcx>, - - /// def_id of the opaque type whose defining uses are being checked - def_id: LocalDefId, - - found: ty::OpaqueHiddenType<'tcx>, - } - - impl ConstraintChecker<'_> { - #[instrument(skip(self), level = "debug")] - fn check(&self, def_id: LocalDefId) { - // Use borrowck to get the type with unerased regions. - let concrete_opaque_types = &self.tcx.mir_borrowck(def_id).concrete_opaque_types; - debug!(?concrete_opaque_types); - for (&def_id, &concrete_type) in concrete_opaque_types { - if def_id != self.def_id { - // Ignore constraints for other opaque types. - continue; - } - - debug!(?concrete_type, "found constraint"); - - if concrete_type.ty != self.found.ty - && !(concrete_type, self.found).references_error() - { - self.found.report_mismatch(&concrete_type, self.tcx); - } - } - } - } - - impl<'tcx> intravisit::Visitor<'tcx> for ConstraintChecker<'tcx> { - type NestedFilter = nested_filter::OnlyBodies; - - fn nested_visit_map(&mut self) -> Self::Map { - self.tcx.hir() - } - fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) { - if let hir::ExprKind::Closure(closure) = ex.kind { - self.check(closure.def_id); - } - intravisit::walk_expr(self, ex); - } - fn visit_item(&mut self, it: &'tcx Item<'tcx>) { - trace!(?it.owner_id); - // The opaque type itself or its children are not within its reveal scope. - if it.owner_id.def_id != self.def_id { - self.check(it.owner_id.def_id); - intravisit::walk_item(self, it); - } - } - fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) { - trace!(?it.owner_id); - // The opaque type itself or its children are not within its reveal scope. - if it.owner_id.def_id != self.def_id { - self.check(it.owner_id.def_id); - intravisit::walk_impl_item(self, it); - } - } - fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) { - trace!(?it.owner_id); - self.check(it.owner_id.def_id); - intravisit::walk_trait_item(self, it); - } - } - - let concrete = tcx.mir_borrowck(owner_def_id).concrete_opaque_types.get(&def_id).copied(); - - if let Some(concrete) = concrete { - let scope = tcx.hir().local_def_id_to_hir_id(owner_def_id); - debug!(?scope); - let mut locator = ConstraintChecker { def_id, tcx, found: concrete }; - - match tcx.hir().get(scope) { - Node::Item(it) => intravisit::walk_item(&mut locator, it), - Node::ImplItem(it) => intravisit::walk_impl_item(&mut locator, it), - Node::TraitItem(it) => intravisit::walk_trait_item(&mut locator, it), - other => bug!("{:?} is not a valid scope for an opaque type item", other), - } - } - - concrete.map(|concrete| concrete.ty).unwrap_or_else(|| { - let table = tcx.typeck(owner_def_id); - if let Some(guar) = table.tainted_by_errors { - // Some error in the - // owner fn prevented us from populating - // the `concrete_opaque_types` table. - tcx.ty_error(guar) - } else { - table.concrete_opaque_types.get(&def_id).map(|ty| ty.ty).unwrap_or_else(|| { - // We failed to resolve the opaque type or it - // resolves to itself. We interpret this as the - // no values of the hidden type ever being constructed, - // so we can just make the hidden type be `!`. - // For backwards compatibility reasons, we fall back to - // `()` until we the diverging default is changed. - tcx.mk_diverging_default() - }) - } - }) -} - fn infer_placeholder_type<'a>( tcx: TyCtxt<'a>, def_id: LocalDefId, @@ -893,14 +530,14 @@ fn infer_placeholder_type<'a>( if let Some(ty) = ty.make_suggestable(tcx, false) { err.span_suggestion( span, - &format!("provide a type for the {item}", item = kind), + format!("provide a type for the {item}", item = kind), format!("{colon} {ty}"), Applicability::MachineApplicable, ); } else { with_forced_trimmed_paths!(err.span_note( tcx.hir().body(body_id).value.span, - &format!("however, the inferred type `{ty}` cannot be named"), + format!("however, the inferred type `{ty}` cannot be named"), )); } } @@ -921,7 +558,7 @@ fn infer_placeholder_type<'a>( } else { with_forced_trimmed_paths!(diag.span_note( tcx.hir().body(body_id).value.span, - &format!("however, the inferred type `{ty}` cannot be named"), + format!("however, the inferred type `{ty}` cannot be named"), )); } } diff --git a/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs b/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs new file mode 100644 index 000000000..f7c5b4467 --- /dev/null +++ b/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs @@ -0,0 +1,298 @@ +use rustc_hir::def_id::LocalDefId; +use rustc_hir::intravisit::{self, Visitor}; +use rustc_hir::{self as hir, Expr, ImplItem, Item, Node, TraitItem}; +use rustc_middle::hir::nested_filter; +use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt}; +use rustc_span::DUMMY_SP; + +use crate::errors::UnconstrainedOpaqueType; + +/// Checks "defining uses" of opaque `impl Trait` types to ensure that they meet the restrictions +/// laid for "higher-order pattern unification". +/// This ensures that inference is tractable. +/// In particular, definitions of opaque types can only use other generics as arguments, +/// and they cannot repeat an argument. Example: +/// +/// ```ignore (illustrative) +/// type Foo<A, B> = impl Bar<A, B>; +/// +/// // Okay -- `Foo` is applied to two distinct, generic types. +/// fn a<T, U>() -> Foo<T, U> { .. } +/// +/// // Not okay -- `Foo` is applied to `T` twice. +/// fn b<T>() -> Foo<T, T> { .. } +/// +/// // Not okay -- `Foo` is applied to a non-generic type. +/// fn b<T>() -> Foo<T, u32> { .. } +/// ``` +#[instrument(skip(tcx), level = "debug")] +pub(super) fn find_opaque_ty_constraints_for_tait(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Ty<'_> { + let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); + let scope = tcx.hir().get_defining_scope(hir_id); + let mut locator = TaitConstraintLocator { def_id, tcx, found: None, typeck_types: vec![] }; + + debug!(?scope); + + if scope == hir::CRATE_HIR_ID { + tcx.hir().walk_toplevel_module(&mut locator); + } else { + trace!("scope={:#?}", tcx.hir().get(scope)); + match tcx.hir().get(scope) { + // We explicitly call `visit_*` methods, instead of using `intravisit::walk_*` methods + // This allows our visitor to process the defining item itself, causing + // it to pick up any 'sibling' defining uses. + // + // For example, this code: + // ``` + // fn foo() { + // type Blah = impl Debug; + // let my_closure = || -> Blah { true }; + // } + // ``` + // + // requires us to explicitly process `foo()` in order + // to notice the defining usage of `Blah`. + Node::Item(it) => locator.visit_item(it), + Node::ImplItem(it) => locator.visit_impl_item(it), + Node::TraitItem(it) => locator.visit_trait_item(it), + other => bug!("{:?} is not a valid scope for an opaque type item", other), + } + } + + let Some(hidden) = locator.found else { + let reported = tcx.sess.emit_err(UnconstrainedOpaqueType { + span: tcx.def_span(def_id), + name: tcx.item_name(tcx.local_parent(def_id).to_def_id()), + what: match tcx.hir().get(scope) { + _ if scope == hir::CRATE_HIR_ID => "module", + Node::Item(hir::Item { kind: hir::ItemKind::Mod(_), .. }) => "module", + Node::Item(hir::Item { kind: hir::ItemKind::Impl(_), .. }) => "impl", + _ => "item", + }, + }); + return tcx.ty_error(reported); + }; + + // Only check against typeck if we didn't already error + if !hidden.ty.references_error() { + for concrete_type in locator.typeck_types { + if concrete_type.ty != tcx.erase_regions(hidden.ty) + && !(concrete_type, hidden).references_error() + { + hidden.report_mismatch(&concrete_type, def_id, tcx).emit(); + } + } + } + + hidden.ty +} + +struct TaitConstraintLocator<'tcx> { + tcx: TyCtxt<'tcx>, + + /// def_id of the opaque type whose defining uses are being checked + def_id: LocalDefId, + + /// as we walk the defining uses, we are checking that all of them + /// define the same hidden type. This variable is set to `Some` + /// with the first type that we find, and then later types are + /// checked against it (we also carry the span of that first + /// type). + found: Option<ty::OpaqueHiddenType<'tcx>>, + + /// In the presence of dead code, typeck may figure out a hidden type + /// while borrowck will not. We collect these cases here and check at + /// the end that we actually found a type that matches (modulo regions). + typeck_types: Vec<ty::OpaqueHiddenType<'tcx>>, +} + +impl TaitConstraintLocator<'_> { + #[instrument(skip(self), level = "debug")] + fn check(&mut self, item_def_id: LocalDefId) { + // Don't try to check items that cannot possibly constrain the type. + if !self.tcx.has_typeck_results(item_def_id) { + debug!("no constraint: no typeck results"); + return; + } + // Calling `mir_borrowck` can lead to cycle errors through + // const-checking, avoid calling it if we don't have to. + // ```rust + // type Foo = impl Fn() -> usize; // when computing type for this + // const fn bar() -> Foo { + // || 0usize + // } + // const BAZR: Foo = bar(); // we would mir-borrowck this, causing cycles + // // because we again need to reveal `Foo` so we can check whether the + // // constant does not contain interior mutability. + // ``` + let tables = self.tcx.typeck(item_def_id); + if let Some(guar) = tables.tainted_by_errors { + self.found = Some(ty::OpaqueHiddenType { span: DUMMY_SP, ty: self.tcx.ty_error(guar) }); + return; + } + let Some(&typeck_hidden_ty) = tables.concrete_opaque_types.get(&self.def_id) else { + debug!("no constraints in typeck results"); + return; + }; + if self.typeck_types.iter().all(|prev| prev.ty != typeck_hidden_ty.ty) { + self.typeck_types.push(typeck_hidden_ty); + } + + // Use borrowck to get the type with unerased regions. + let concrete_opaque_types = &self.tcx.mir_borrowck(item_def_id).concrete_opaque_types; + debug!(?concrete_opaque_types); + if let Some(&concrete_type) = concrete_opaque_types.get(&self.def_id) { + debug!(?concrete_type, "found constraint"); + if let Some(prev) = &mut self.found { + if concrete_type.ty != prev.ty && !(concrete_type, prev.ty).references_error() { + let guar = prev.report_mismatch(&concrete_type, self.def_id, self.tcx).emit(); + prev.ty = self.tcx.ty_error(guar); + } + } else { + self.found = Some(concrete_type); + } + } + } +} + +impl<'tcx> intravisit::Visitor<'tcx> for TaitConstraintLocator<'tcx> { + type NestedFilter = nested_filter::All; + + fn nested_visit_map(&mut self) -> Self::Map { + self.tcx.hir() + } + fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) { + if let hir::ExprKind::Closure(closure) = ex.kind { + self.check(closure.def_id); + } + intravisit::walk_expr(self, ex); + } + fn visit_item(&mut self, it: &'tcx Item<'tcx>) { + trace!(?it.owner_id); + // The opaque type itself or its children are not within its reveal scope. + if it.owner_id.def_id != self.def_id { + self.check(it.owner_id.def_id); + intravisit::walk_item(self, it); + } + } + fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) { + trace!(?it.owner_id); + // The opaque type itself or its children are not within its reveal scope. + if it.owner_id.def_id != self.def_id { + self.check(it.owner_id.def_id); + intravisit::walk_impl_item(self, it); + } + } + fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) { + trace!(?it.owner_id); + self.check(it.owner_id.def_id); + intravisit::walk_trait_item(self, it); + } +} + +pub(super) fn find_opaque_ty_constraints_for_rpit( + tcx: TyCtxt<'_>, + def_id: LocalDefId, + owner_def_id: LocalDefId, +) -> Ty<'_> { + let concrete = tcx.mir_borrowck(owner_def_id).concrete_opaque_types.get(&def_id).copied(); + + if let Some(concrete) = concrete { + let scope = tcx.hir().local_def_id_to_hir_id(owner_def_id); + debug!(?scope); + let mut locator = RpitConstraintChecker { def_id, tcx, found: concrete }; + + match tcx.hir().get(scope) { + Node::Item(it) => intravisit::walk_item(&mut locator, it), + Node::ImplItem(it) => intravisit::walk_impl_item(&mut locator, it), + Node::TraitItem(it) => intravisit::walk_trait_item(&mut locator, it), + other => bug!("{:?} is not a valid scope for an opaque type item", other), + } + } + + concrete.map(|concrete| concrete.ty).unwrap_or_else(|| { + let table = tcx.typeck(owner_def_id); + if let Some(guar) = table.tainted_by_errors { + // Some error in the + // owner fn prevented us from populating + // the `concrete_opaque_types` table. + tcx.ty_error(guar) + } else { + table.concrete_opaque_types.get(&def_id).map(|ty| ty.ty).unwrap_or_else(|| { + // We failed to resolve the opaque type or it + // resolves to itself. We interpret this as the + // no values of the hidden type ever being constructed, + // so we can just make the hidden type be `!`. + // For backwards compatibility reasons, we fall back to + // `()` until we the diverging default is changed. + tcx.mk_diverging_default() + }) + } + }) +} + +struct RpitConstraintChecker<'tcx> { + tcx: TyCtxt<'tcx>, + + /// def_id of the opaque type whose defining uses are being checked + def_id: LocalDefId, + + found: ty::OpaqueHiddenType<'tcx>, +} + +impl RpitConstraintChecker<'_> { + #[instrument(skip(self), level = "debug")] + fn check(&self, def_id: LocalDefId) { + // Use borrowck to get the type with unerased regions. + let concrete_opaque_types = &self.tcx.mir_borrowck(def_id).concrete_opaque_types; + debug!(?concrete_opaque_types); + for (&def_id, &concrete_type) in concrete_opaque_types { + if def_id != self.def_id { + // Ignore constraints for other opaque types. + continue; + } + + debug!(?concrete_type, "found constraint"); + + if concrete_type.ty != self.found.ty && !(concrete_type, self.found).references_error() + { + self.found.report_mismatch(&concrete_type, self.def_id, self.tcx).emit(); + } + } + } +} + +impl<'tcx> intravisit::Visitor<'tcx> for RpitConstraintChecker<'tcx> { + type NestedFilter = nested_filter::OnlyBodies; + + fn nested_visit_map(&mut self) -> Self::Map { + self.tcx.hir() + } + fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) { + if let hir::ExprKind::Closure(closure) = ex.kind { + self.check(closure.def_id); + } + intravisit::walk_expr(self, ex); + } + fn visit_item(&mut self, it: &'tcx Item<'tcx>) { + trace!(?it.owner_id); + // The opaque type itself or its children are not within its reveal scope. + if it.owner_id.def_id != self.def_id { + self.check(it.owner_id.def_id); + intravisit::walk_item(self, it); + } + } + fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) { + trace!(?it.owner_id); + // The opaque type itself or its children are not within its reveal scope. + if it.owner_id.def_id != self.def_id { + self.check(it.owner_id.def_id); + intravisit::walk_impl_item(self, it); + } + } + fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) { + trace!(?it.owner_id); + self.check(it.owner_id.def_id); + intravisit::walk_trait_item(self, it); + } +} |