diff options
Diffstat (limited to '')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/check.rs | 1443 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/compare_method.rs | 1825 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/dropck.rs (renamed from compiler/rustc_typeck/src/check/dropck.rs) | 14 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/intrinsic.rs (renamed from compiler/rustc_typeck/src/check/intrinsic.rs) | 60 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/intrinsicck.rs | 437 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/mod.rs | 515 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/region.rs (renamed from compiler/rustc_typeck/src/check/region.rs) | 51 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/wfcheck.rs (renamed from compiler/rustc_typeck/src/check/wfcheck.rs) | 367 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check_unused.rs | 192 |
9 files changed, 4690 insertions, 214 deletions
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs new file mode 100644 index 000000000..b70ac0205 --- /dev/null +++ b/compiler/rustc_hir_analysis/src/check/check.rs @@ -0,0 +1,1443 @@ +use crate::check::intrinsicck::InlineAsmCtxt; + +use super::compare_method::check_type_bounds; +use super::compare_method::{compare_impl_method, compare_ty_impl}; +use super::*; +use rustc_attr as attr; +use rustc_errors::{Applicability, ErrorGuaranteed, MultiSpan}; +use rustc_hir as hir; +use rustc_hir::def::{DefKind, Res}; +use rustc_hir::def_id::{DefId, LocalDefId}; +use rustc_hir::intravisit::Visitor; +use rustc_hir::{ItemKind, Node, PathSegment}; +use rustc_infer::infer::outlives::env::OutlivesEnvironment; +use rustc_infer::infer::{DefiningAnchor, RegionVariableOrigin, TyCtxtInferExt}; +use rustc_infer::traits::Obligation; +use rustc_lint::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS; +use rustc_middle::hir::nested_filter; +use rustc_middle::middle::stability::EvalResult; +use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES}; +use rustc_middle::ty::subst::GenericArgKind; +use rustc_middle::ty::util::{Discr, IntTypeExt}; +use rustc_middle::ty::{ + self, ParamEnv, ToPredicate, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, +}; +use rustc_session::lint::builtin::{UNINHABITED_STATIC, UNSUPPORTED_CALLING_CONVENTIONS}; +use rustc_span::symbol::sym; +use rustc_span::{self, Span}; +use rustc_target::spec::abi::Abi; +use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _; +use rustc_trait_selection::traits::{self, ObligationCtxt}; + +use std::ops::ControlFlow; + +pub fn check_abi(tcx: TyCtxt<'_>, hir_id: hir::HirId, span: Span, abi: Abi) { + match tcx.sess.target.is_abi_supported(abi) { + Some(true) => (), + Some(false) => { + struct_span_err!( + tcx.sess, + span, + E0570, + "`{abi}` is not a supported ABI for the current target", + ) + .emit(); + } + None => { + tcx.struct_span_lint_hir( + UNSUPPORTED_CALLING_CONVENTIONS, + hir_id, + span, + "use of calling convention not supported on this target", + |lint| lint, + ); + } + } + + // This ABI is only allowed on function pointers + if abi == Abi::CCmseNonSecureCall { + struct_span_err!( + tcx.sess, + span, + E0781, + "the `\"C-cmse-nonsecure-call\"` ABI is only allowed on function pointers" + ) + .emit(); + } +} + +fn check_struct(tcx: TyCtxt<'_>, def_id: LocalDefId) { + let def = tcx.adt_def(def_id); + let span = tcx.def_span(def_id); + def.destructor(tcx); // force the destructor to be evaluated + + if def.repr().simd() { + check_simd(tcx, span, def_id); + } + + check_transparent(tcx, span, def); + check_packed(tcx, span, def); +} + +fn check_union(tcx: TyCtxt<'_>, def_id: LocalDefId) { + let def = tcx.adt_def(def_id); + let span = tcx.def_span(def_id); + def.destructor(tcx); // force the destructor to be evaluated + check_transparent(tcx, span, def); + check_union_fields(tcx, span, def_id); + check_packed(tcx, span, def); +} + +/// Check that the fields of the `union` do not need dropping. +fn check_union_fields(tcx: TyCtxt<'_>, span: Span, item_def_id: LocalDefId) -> bool { + let item_type = tcx.type_of(item_def_id); + if let ty::Adt(def, substs) = item_type.kind() { + assert!(def.is_union()); + + fn allowed_union_field<'tcx>( + ty: Ty<'tcx>, + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + span: Span, + ) -> bool { + // We don't just accept all !needs_drop fields, due to semver concerns. + match ty.kind() { + ty::Ref(..) => true, // references never drop (even mutable refs, which are non-Copy and hence fail the later check) + ty::Tuple(tys) => { + // allow tuples of allowed types + tys.iter().all(|ty| allowed_union_field(ty, tcx, param_env, span)) + } + ty::Array(elem, _len) => { + // Like `Copy`, we do *not* special-case length 0. + allowed_union_field(*elem, tcx, param_env, span) + } + _ => { + // Fallback case: allow `ManuallyDrop` and things that are `Copy`. + ty.ty_adt_def().is_some_and(|adt_def| adt_def.is_manually_drop()) + || ty.is_copy_modulo_regions(tcx, param_env) + } + } + } + + let param_env = tcx.param_env(item_def_id); + for field in &def.non_enum_variant().fields { + let field_ty = field.ty(tcx, substs); + + if !allowed_union_field(field_ty, tcx, param_env, span) { + let (field_span, ty_span) = match tcx.hir().get_if_local(field.did) { + // We are currently checking the type this field came from, so it must be local. + Some(Node::Field(field)) => (field.span, field.ty.span), + _ => unreachable!("mir field has to correspond to hir field"), + }; + struct_span_err!( + tcx.sess, + field_span, + E0740, + "unions cannot contain fields that may need dropping" + ) + .note( + "a type is guaranteed not to need dropping \ + when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type", + ) + .multipart_suggestion_verbose( + "when the type does not implement `Copy`, \ + wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped", + vec![ + (ty_span.shrink_to_lo(), "std::mem::ManuallyDrop<".into()), + (ty_span.shrink_to_hi(), ">".into()), + ], + Applicability::MaybeIncorrect, + ) + .emit(); + return false; + } else if field_ty.needs_drop(tcx, param_env) { + // This should never happen. But we can get here e.g. in case of name resolution errors. + tcx.sess.delay_span_bug(span, "we should never accept maybe-dropping union fields"); + } + } + } else { + span_bug!(span, "unions must be ty::Adt, but got {:?}", item_type.kind()); + } + true +} + +/// Check that a `static` is inhabited. +fn check_static_inhabited<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) { + // Make sure statics are inhabited. + // Other parts of the compiler assume that there are no uninhabited places. In principle it + // would be enough to check this for `extern` statics, as statics with an initializer will + // have UB during initialization if they are uninhabited, but there also seems to be no good + // reason to allow any statics to be uninhabited. + let ty = tcx.type_of(def_id); + let span = tcx.def_span(def_id); + let layout = match tcx.layout_of(ParamEnv::reveal_all().and(ty)) { + Ok(l) => l, + // Foreign statics that overflow their allowed size should emit an error + Err(LayoutError::SizeOverflow(_)) + if { + let node = tcx.hir().get_by_def_id(def_id); + matches!( + node, + hir::Node::ForeignItem(hir::ForeignItem { + kind: hir::ForeignItemKind::Static(..), + .. + }) + ) + } => + { + tcx.sess + .struct_span_err(span, "extern static is too large for the current architecture") + .emit(); + return; + } + // Generic statics are rejected, but we still reach this case. + Err(e) => { + tcx.sess.delay_span_bug(span, &e.to_string()); + return; + } + }; + if layout.abi.is_uninhabited() { + tcx.struct_span_lint_hir( + UNINHABITED_STATIC, + tcx.hir().local_def_id_to_hir_id(def_id), + span, + "static of uninhabited type", + |lint| { + lint + .note("uninhabited statics cannot be initialized, and any access would be an immediate error") + }, + ); + } +} + +/// Checks that an opaque type does not contain cycles and does not use `Self` or `T::Foo` +/// projections that would result in "inheriting lifetimes". +fn check_opaque<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) { + let item = tcx.hir().item(id); + let hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) = item.kind else { + tcx.sess.delay_span_bug(tcx.hir().span(id.hir_id()), "expected opaque item"); + return; + }; + + // HACK(jynelson): trying to infer the type of `impl trait` breaks documenting + // `async-std` (and `pub async fn` in general). + // Since rustdoc doesn't care about the concrete type behind `impl Trait`, just don't look at it! + // See https://github.com/rust-lang/rust/issues/75100 + if tcx.sess.opts.actually_rustdoc { + return; + } + + let substs = InternalSubsts::identity_for_item(tcx, item.owner_id.to_def_id()); + let span = tcx.def_span(item.owner_id.def_id); + + check_opaque_for_inheriting_lifetimes(tcx, item.owner_id.def_id, span); + if tcx.type_of(item.owner_id.def_id).references_error() { + return; + } + if check_opaque_for_cycles(tcx, item.owner_id.def_id, substs, span, &origin).is_err() { + return; + } + check_opaque_meets_bounds(tcx, item.owner_id.def_id, substs, span, &origin); +} +/// Checks that an opaque type does not use `Self` or `T::Foo` projections that would result +/// in "inheriting lifetimes". +#[instrument(level = "debug", skip(tcx, span))] +pub(super) fn check_opaque_for_inheriting_lifetimes<'tcx>( + tcx: TyCtxt<'tcx>, + def_id: LocalDefId, + span: Span, +) { + let item = tcx.hir().expect_item(def_id); + debug!(?item, ?span); + + struct FoundParentLifetime; + struct FindParentLifetimeVisitor<'tcx>(&'tcx ty::Generics); + impl<'tcx> ty::visit::TypeVisitor<'tcx> for FindParentLifetimeVisitor<'tcx> { + type BreakTy = FoundParentLifetime; + + fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> { + debug!("FindParentLifetimeVisitor: r={:?}", r); + if let ty::ReEarlyBound(ty::EarlyBoundRegion { index, .. }) = *r { + if index < self.0.parent_count as u32 { + return ControlFlow::Break(FoundParentLifetime); + } else { + return ControlFlow::CONTINUE; + } + } + + r.super_visit_with(self) + } + + fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> { + if let ty::ConstKind::Unevaluated(..) = c.kind() { + // FIXME(#72219) We currently don't detect lifetimes within substs + // which would violate this check. Even though the particular substitution is not used + // within the const, this should still be fixed. + return ControlFlow::CONTINUE; + } + c.super_visit_with(self) + } + } + + struct ProhibitOpaqueVisitor<'tcx> { + tcx: TyCtxt<'tcx>, + opaque_identity_ty: Ty<'tcx>, + generics: &'tcx ty::Generics, + selftys: Vec<(Span, Option<String>)>, + } + + impl<'tcx> ty::visit::TypeVisitor<'tcx> for ProhibitOpaqueVisitor<'tcx> { + type BreakTy = Ty<'tcx>; + + fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { + debug!("check_opaque_for_inheriting_lifetimes: (visit_ty) t={:?}", t); + if t == self.opaque_identity_ty { + ControlFlow::CONTINUE + } else { + t.super_visit_with(&mut FindParentLifetimeVisitor(self.generics)) + .map_break(|FoundParentLifetime| t) + } + } + } + + impl<'tcx> Visitor<'tcx> for ProhibitOpaqueVisitor<'tcx> { + type NestedFilter = nested_filter::OnlyBodies; + + fn nested_visit_map(&mut self) -> Self::Map { + self.tcx.hir() + } + + fn visit_ty(&mut self, arg: &'tcx hir::Ty<'tcx>) { + match arg.kind { + hir::TyKind::Path(hir::QPath::Resolved(None, path)) => match &path.segments { + [PathSegment { res: Res::SelfTyParam { .. }, .. }] => { + let impl_ty_name = None; + self.selftys.push((path.span, impl_ty_name)); + } + [PathSegment { res: Res::SelfTyAlias { alias_to: def_id, .. }, .. }] => { + let impl_ty_name = Some(self.tcx.def_path_str(*def_id)); + self.selftys.push((path.span, impl_ty_name)); + } + _ => {} + }, + _ => {} + } + hir::intravisit::walk_ty(self, arg); + } + } + + if let ItemKind::OpaqueTy(hir::OpaqueTy { + origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..), + .. + }) = item.kind + { + let mut visitor = ProhibitOpaqueVisitor { + opaque_identity_ty: tcx.mk_opaque( + def_id.to_def_id(), + InternalSubsts::identity_for_item(tcx, def_id.to_def_id()), + ), + generics: tcx.generics_of(def_id), + tcx, + selftys: vec![], + }; + let prohibit_opaque = tcx + .explicit_item_bounds(def_id) + .iter() + .try_for_each(|(predicate, _)| predicate.visit_with(&mut visitor)); + debug!( + "check_opaque_for_inheriting_lifetimes: prohibit_opaque={:?}, visitor.opaque_identity_ty={:?}, visitor.generics={:?}", + prohibit_opaque, visitor.opaque_identity_ty, visitor.generics + ); + + if let Some(ty) = prohibit_opaque.break_value() { + visitor.visit_item(&item); + let is_async = match item.kind { + ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => { + matches!(origin, hir::OpaqueTyOrigin::AsyncFn(..)) + } + _ => unreachable!(), + }; + + let mut err = struct_span_err!( + tcx.sess, + span, + E0760, + "`{}` return type cannot contain a projection or `Self` that references lifetimes from \ + a parent scope", + if is_async { "async fn" } else { "impl Trait" }, + ); + + for (span, name) in visitor.selftys { + err.span_suggestion( + span, + "consider spelling out the type instead", + name.unwrap_or_else(|| format!("{:?}", ty)), + Applicability::MaybeIncorrect, + ); + } + err.emit(); + } + } +} + +/// Checks that an opaque type does not contain cycles. +pub(super) fn check_opaque_for_cycles<'tcx>( + tcx: TyCtxt<'tcx>, + def_id: LocalDefId, + substs: SubstsRef<'tcx>, + span: Span, + origin: &hir::OpaqueTyOrigin, +) -> Result<(), ErrorGuaranteed> { + if tcx.try_expand_impl_trait_type(def_id.to_def_id(), substs).is_err() { + let reported = match origin { + hir::OpaqueTyOrigin::AsyncFn(..) => async_opaque_type_cycle_error(tcx, span), + _ => opaque_type_cycle_error(tcx, def_id, span), + }; + Err(reported) + } else { + Ok(()) + } +} + +/// Check that the concrete type behind `impl Trait` actually implements `Trait`. +/// +/// This is mostly checked at the places that specify the opaque type, but we +/// check those cases in the `param_env` of that function, which may have +/// bounds not on this opaque type: +/// +/// ```ignore (illustrative) +/// type X<T> = impl Clone; +/// fn f<T: Clone>(t: T) -> X<T> { +/// t +/// } +/// ``` +/// +/// Without this check the above code is incorrectly accepted: we would ICE if +/// some tried, for example, to clone an `Option<X<&mut ()>>`. +#[instrument(level = "debug", skip(tcx))] +fn check_opaque_meets_bounds<'tcx>( + tcx: TyCtxt<'tcx>, + def_id: LocalDefId, + substs: SubstsRef<'tcx>, + span: Span, + origin: &hir::OpaqueTyOrigin, +) { + let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); + let defining_use_anchor = match *origin { + hir::OpaqueTyOrigin::FnReturn(did) | hir::OpaqueTyOrigin::AsyncFn(did) => did, + hir::OpaqueTyOrigin::TyAlias => def_id, + }; + let param_env = tcx.param_env(defining_use_anchor); + + let infcx = tcx + .infer_ctxt() + .with_opaque_type_inference(DefiningAnchor::Bind(defining_use_anchor)) + .build(); + let ocx = ObligationCtxt::new(&infcx); + let opaque_ty = tcx.mk_opaque(def_id.to_def_id(), substs); + + // `ReErased` regions appear in the "parent_substs" of closures/generators. + // We're ignoring them here and replacing them with fresh region variables. + // See tests in ui/type-alias-impl-trait/closure_{parent_substs,wf_outlives}.rs. + // + // FIXME: Consider wrapping the hidden type in an existential `Binder` and instantiating it + // here rather than using ReErased. + let hidden_ty = tcx.bound_type_of(def_id.to_def_id()).subst(tcx, substs); + let hidden_ty = tcx.fold_regions(hidden_ty, |re, _dbi| match re.kind() { + ty::ReErased => infcx.next_region_var(RegionVariableOrigin::MiscVariable(span)), + _ => re, + }); + + let misc_cause = traits::ObligationCause::misc(span, hir_id); + + match infcx.at(&misc_cause, param_env).eq(opaque_ty, hidden_ty) { + Ok(infer_ok) => ocx.register_infer_ok_obligations(infer_ok), + Err(ty_err) => { + tcx.sess.delay_span_bug( + span, + &format!("could not unify `{hidden_ty}` with revealed type:\n{ty_err}"), + ); + } + } + + // Additionally require the hidden type to be well-formed with only the generics of the opaque type. + // Defining use functions may have more bounds than the opaque type, which is ok, as long as the + // hidden type is well formed even without those bounds. + let predicate = + ty::Binder::dummy(ty::PredicateKind::WellFormed(hidden_ty.into())).to_predicate(tcx); + ocx.register_obligation(Obligation::new(misc_cause, param_env, predicate)); + + // Check that all obligations are satisfied by the implementation's + // version. + let errors = ocx.select_all_or_error(); + if !errors.is_empty() { + infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); + } + match origin { + // Checked when type checking the function containing them. + hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => {} + // Can have different predicates to their defining use + hir::OpaqueTyOrigin::TyAlias => { + let outlives_environment = OutlivesEnvironment::new(param_env); + infcx.check_region_obligations_and_report_errors( + defining_use_anchor, + &outlives_environment, + ); + } + } + // Clean up after ourselves + let _ = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types(); +} + +fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) { + debug!( + "check_item_type(it.def_id={:?}, it.name={})", + id.owner_id, + tcx.def_path_str(id.owner_id.to_def_id()) + ); + let _indenter = indenter(); + match tcx.def_kind(id.owner_id) { + DefKind::Static(..) => { + tcx.ensure().typeck(id.owner_id.def_id); + maybe_check_static_with_link_section(tcx, id.owner_id.def_id); + check_static_inhabited(tcx, id.owner_id.def_id); + } + DefKind::Const => { + tcx.ensure().typeck(id.owner_id.def_id); + } + DefKind::Enum => { + let item = tcx.hir().item(id); + let hir::ItemKind::Enum(ref enum_definition, _) = item.kind else { + return; + }; + check_enum(tcx, &enum_definition.variants, item.owner_id.def_id); + } + DefKind::Fn => {} // entirely within check_item_body + DefKind::Impl => { + let it = tcx.hir().item(id); + let hir::ItemKind::Impl(ref impl_) = it.kind else { + return; + }; + debug!("ItemKind::Impl {} with id {:?}", it.ident, it.owner_id); + if let Some(impl_trait_ref) = tcx.impl_trait_ref(it.owner_id) { + check_impl_items_against_trait( + tcx, + it.span, + it.owner_id.def_id, + impl_trait_ref, + &impl_.items, + ); + check_on_unimplemented(tcx, it); + } + } + DefKind::Trait => { + let it = tcx.hir().item(id); + let hir::ItemKind::Trait(_, _, _, _, ref items) = it.kind else { + return; + }; + check_on_unimplemented(tcx, it); + + for item in items.iter() { + let item = tcx.hir().trait_item(item.id); + match item.kind { + hir::TraitItemKind::Fn(ref sig, _) => { + let abi = sig.header.abi; + fn_maybe_err(tcx, item.ident.span, abi); + } + hir::TraitItemKind::Type(.., Some(default)) => { + let assoc_item = tcx.associated_item(item.owner_id); + let trait_substs = + InternalSubsts::identity_for_item(tcx, it.owner_id.to_def_id()); + let _: Result<_, rustc_errors::ErrorGuaranteed> = check_type_bounds( + tcx, + assoc_item, + assoc_item, + default.span, + ty::TraitRef { def_id: it.owner_id.to_def_id(), substs: trait_substs }, + ); + } + _ => {} + } + } + } + DefKind::Struct => { + check_struct(tcx, id.owner_id.def_id); + } + DefKind::Union => { + check_union(tcx, id.owner_id.def_id); + } + DefKind::OpaqueTy => { + check_opaque(tcx, id); + } + DefKind::ImplTraitPlaceholder => { + let parent = tcx.impl_trait_in_trait_parent(id.owner_id.to_def_id()); + // Only check the validity of this opaque type if the function has a default body + if let hir::Node::TraitItem(hir::TraitItem { + kind: hir::TraitItemKind::Fn(_, hir::TraitFn::Provided(_)), + .. + }) = tcx.hir().get_by_def_id(parent.expect_local()) + { + check_opaque(tcx, id); + } + } + DefKind::TyAlias => { + let pty_ty = tcx.type_of(id.owner_id); + let generics = tcx.generics_of(id.owner_id); + check_type_params_are_used(tcx, &generics, pty_ty); + } + DefKind::ForeignMod => { + let it = tcx.hir().item(id); + let hir::ItemKind::ForeignMod { abi, items } = it.kind else { + return; + }; + check_abi(tcx, it.hir_id(), it.span, abi); + + if abi == Abi::RustIntrinsic { + for item in items { + let item = tcx.hir().foreign_item(item.id); + intrinsic::check_intrinsic_type(tcx, item); + } + } else if abi == Abi::PlatformIntrinsic { + for item in items { + let item = tcx.hir().foreign_item(item.id); + intrinsic::check_platform_intrinsic_type(tcx, item); + } + } else { + for item in items { + let def_id = item.id.owner_id.def_id; + let generics = tcx.generics_of(def_id); + let own_counts = generics.own_counts(); + if generics.params.len() - own_counts.lifetimes != 0 { + let (kinds, kinds_pl, egs) = match (own_counts.types, own_counts.consts) { + (_, 0) => ("type", "types", Some("u32")), + // We don't specify an example value, because we can't generate + // a valid value for any type. + (0, _) => ("const", "consts", None), + _ => ("type or const", "types or consts", None), + }; + struct_span_err!( + tcx.sess, + item.span, + E0044, + "foreign items may not have {kinds} parameters", + ) + .span_label(item.span, &format!("can't have {kinds} parameters")) + .help( + // FIXME: once we start storing spans for type arguments, turn this + // into a suggestion. + &format!( + "replace the {} parameters with concrete {}{}", + kinds, + kinds_pl, + egs.map(|egs| format!(" like `{}`", egs)).unwrap_or_default(), + ), + ) + .emit(); + } + + let item = tcx.hir().foreign_item(item.id); + match item.kind { + hir::ForeignItemKind::Fn(ref fn_decl, _, _) => { + require_c_abi_if_c_variadic(tcx, fn_decl, abi, item.span); + } + hir::ForeignItemKind::Static(..) => { + check_static_inhabited(tcx, def_id); + } + _ => {} + } + } + } + } + DefKind::GlobalAsm => { + let it = tcx.hir().item(id); + let hir::ItemKind::GlobalAsm(asm) = it.kind else { span_bug!(it.span, "DefKind::GlobalAsm but got {:#?}", it) }; + InlineAsmCtxt::new_global_asm(tcx).check_asm(asm, id.hir_id()); + } + _ => {} + } +} + +pub(super) fn check_on_unimplemented(tcx: TyCtxt<'_>, item: &hir::Item<'_>) { + // an error would be reported if this fails. + let _ = traits::OnUnimplementedDirective::of_item(tcx, item.owner_id.to_def_id()); +} + +pub(super) fn check_specialization_validity<'tcx>( + tcx: TyCtxt<'tcx>, + trait_def: &ty::TraitDef, + trait_item: &ty::AssocItem, + impl_id: DefId, + impl_item: &hir::ImplItemRef, +) { + let Ok(ancestors) = trait_def.ancestors(tcx, impl_id) else { return }; + let mut ancestor_impls = ancestors.skip(1).filter_map(|parent| { + if parent.is_from_trait() { + None + } else { + Some((parent, parent.item(tcx, trait_item.def_id))) + } + }); + + let opt_result = ancestor_impls.find_map(|(parent_impl, parent_item)| { + match parent_item { + // Parent impl exists, and contains the parent item we're trying to specialize, but + // doesn't mark it `default`. + Some(parent_item) if traits::impl_item_is_final(tcx, &parent_item) => { + Some(Err(parent_impl.def_id())) + } + + // Parent impl contains item and makes it specializable. + Some(_) => Some(Ok(())), + + // Parent impl doesn't mention the item. This means it's inherited from the + // grandparent. In that case, if parent is a `default impl`, inherited items use the + // "defaultness" from the grandparent, else they are final. + None => { + if tcx.impl_defaultness(parent_impl.def_id()).is_default() { + None + } else { + Some(Err(parent_impl.def_id())) + } + } + } + }); + + // If `opt_result` is `None`, we have only encountered `default impl`s that don't contain the + // item. This is allowed, the item isn't actually getting specialized here. + let result = opt_result.unwrap_or(Ok(())); + + if let Err(parent_impl) = result { + report_forbidden_specialization(tcx, impl_item, parent_impl); + } +} + +fn check_impl_items_against_trait<'tcx>( + tcx: TyCtxt<'tcx>, + full_impl_span: Span, + impl_id: LocalDefId, + impl_trait_ref: ty::TraitRef<'tcx>, + impl_item_refs: &[hir::ImplItemRef], +) { + // If the trait reference itself is erroneous (so the compilation is going + // to fail), skip checking the items here -- the `impl_item` table in `tcx` + // isn't populated for such impls. + if impl_trait_ref.references_error() { + return; + } + + // Negative impls are not expected to have any items + match tcx.impl_polarity(impl_id) { + ty::ImplPolarity::Reservation | ty::ImplPolarity::Positive => {} + ty::ImplPolarity::Negative => { + if let [first_item_ref, ..] = impl_item_refs { + let first_item_span = tcx.hir().impl_item(first_item_ref.id).span; + struct_span_err!( + tcx.sess, + first_item_span, + E0749, + "negative impls cannot have any items" + ) + .emit(); + } + return; + } + } + + let trait_def = tcx.trait_def(impl_trait_ref.def_id); + + for impl_item in impl_item_refs { + let ty_impl_item = tcx.associated_item(impl_item.id.owner_id); + let ty_trait_item = if let Some(trait_item_id) = ty_impl_item.trait_item_def_id { + tcx.associated_item(trait_item_id) + } else { + // Checked in `associated_item`. + tcx.sess.delay_span_bug(impl_item.span, "missing associated item in trait"); + continue; + }; + let impl_item_full = tcx.hir().impl_item(impl_item.id); + match impl_item_full.kind { + hir::ImplItemKind::Const(..) => { + let _ = tcx.compare_assoc_const_impl_item_with_trait_item(( + impl_item.id.owner_id.def_id, + ty_impl_item.trait_item_def_id.unwrap(), + )); + } + hir::ImplItemKind::Fn(..) => { + let opt_trait_span = tcx.hir().span_if_local(ty_trait_item.def_id); + compare_impl_method( + tcx, + &ty_impl_item, + &ty_trait_item, + impl_trait_ref, + opt_trait_span, + ); + } + hir::ImplItemKind::Type(impl_ty) => { + let opt_trait_span = tcx.hir().span_if_local(ty_trait_item.def_id); + compare_ty_impl( + tcx, + &ty_impl_item, + impl_ty.span, + &ty_trait_item, + impl_trait_ref, + opt_trait_span, + ); + } + } + + check_specialization_validity( + tcx, + trait_def, + &ty_trait_item, + impl_id.to_def_id(), + impl_item, + ); + } + + if let Ok(ancestors) = trait_def.ancestors(tcx, impl_id.to_def_id()) { + // Check for missing items from trait + let mut missing_items = Vec::new(); + + let mut must_implement_one_of: Option<&[Ident]> = + trait_def.must_implement_one_of.as_deref(); + + for &trait_item_id in tcx.associated_item_def_ids(impl_trait_ref.def_id) { + let is_implemented = ancestors + .leaf_def(tcx, trait_item_id) + .map_or(false, |node_item| node_item.item.defaultness(tcx).has_value()); + + if !is_implemented && tcx.impl_defaultness(impl_id).is_final() { + missing_items.push(tcx.associated_item(trait_item_id)); + } + + // true if this item is specifically implemented in this impl + let is_implemented_here = ancestors + .leaf_def(tcx, trait_item_id) + .map_or(false, |node_item| !node_item.defining_node.is_from_trait()); + + if !is_implemented_here { + match tcx.eval_default_body_stability(trait_item_id, full_impl_span) { + EvalResult::Deny { feature, reason, issue, .. } => default_body_is_unstable( + tcx, + full_impl_span, + trait_item_id, + feature, + reason, + issue, + ), + + // Unmarked default bodies are considered stable (at least for now). + EvalResult::Allow | EvalResult::Unmarked => {} + } + } + + if let Some(required_items) = &must_implement_one_of { + if is_implemented_here { + let trait_item = tcx.associated_item(trait_item_id); + if required_items.contains(&trait_item.ident(tcx)) { + must_implement_one_of = None; + } + } + } + } + + if !missing_items.is_empty() { + missing_items_err(tcx, tcx.def_span(impl_id), &missing_items, full_impl_span); + } + + if let Some(missing_items) = must_implement_one_of { + let attr_span = tcx + .get_attr(impl_trait_ref.def_id, sym::rustc_must_implement_one_of) + .map(|attr| attr.span); + + missing_items_must_implement_one_of_err( + tcx, + tcx.def_span(impl_id), + missing_items, + attr_span, + ); + } + } +} + +pub fn check_simd(tcx: TyCtxt<'_>, sp: Span, def_id: LocalDefId) { + let t = tcx.type_of(def_id); + if let ty::Adt(def, substs) = t.kind() + && def.is_struct() + { + let fields = &def.non_enum_variant().fields; + if fields.is_empty() { + struct_span_err!(tcx.sess, sp, E0075, "SIMD vector cannot be empty").emit(); + return; + } + let e = fields[0].ty(tcx, substs); + if !fields.iter().all(|f| f.ty(tcx, substs) == e) { + struct_span_err!(tcx.sess, sp, E0076, "SIMD vector should be homogeneous") + .span_label(sp, "SIMD elements must have the same type") + .emit(); + return; + } + + let len = if let ty::Array(_ty, c) = e.kind() { + c.try_eval_usize(tcx, tcx.param_env(def.did())) + } else { + Some(fields.len() as u64) + }; + if let Some(len) = len { + if len == 0 { + struct_span_err!(tcx.sess, sp, E0075, "SIMD vector cannot be empty").emit(); + return; + } else if len > MAX_SIMD_LANES { + struct_span_err!( + tcx.sess, + sp, + E0075, + "SIMD vector cannot have more than {MAX_SIMD_LANES} elements", + ) + .emit(); + return; + } + } + + // Check that we use types valid for use in the lanes of a SIMD "vector register" + // These are scalar types which directly match a "machine" type + // Yes: Integers, floats, "thin" pointers + // No: char, "fat" pointers, compound types + match e.kind() { + ty::Param(_) => (), // pass struct<T>(T, T, T, T) through, let monomorphization catch errors + ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::RawPtr(_) => (), // struct(u8, u8, u8, u8) is ok + ty::Array(t, _) if matches!(t.kind(), ty::Param(_)) => (), // pass struct<T>([T; N]) through, let monomorphization catch errors + ty::Array(t, _clen) + if matches!( + t.kind(), + ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::RawPtr(_) + ) => + { /* struct([f32; 4]) is ok */ } + _ => { + struct_span_err!( + tcx.sess, + sp, + E0077, + "SIMD vector element type should be a \ + primitive scalar (integer/float/pointer) type" + ) + .emit(); + return; + } + } + } +} + +pub(super) fn check_packed(tcx: TyCtxt<'_>, sp: Span, def: ty::AdtDef<'_>) { + let repr = def.repr(); + if repr.packed() { + for attr in tcx.get_attrs(def.did(), sym::repr) { + for r in attr::parse_repr_attr(&tcx.sess, attr) { + if let attr::ReprPacked(pack) = r + && let Some(repr_pack) = repr.pack + && pack as u64 != repr_pack.bytes() + { + struct_span_err!( + tcx.sess, + sp, + E0634, + "type has conflicting packed representation hints" + ) + .emit(); + } + } + } + if repr.align.is_some() { + struct_span_err!( + tcx.sess, + sp, + E0587, + "type has conflicting packed and align representation hints" + ) + .emit(); + } else { + if let Some(def_spans) = check_packed_inner(tcx, def.did(), &mut vec![]) { + let mut err = struct_span_err!( + tcx.sess, + sp, + E0588, + "packed type cannot transitively contain a `#[repr(align)]` type" + ); + + err.span_note( + tcx.def_span(def_spans[0].0), + &format!( + "`{}` has a `#[repr(align)]` attribute", + tcx.item_name(def_spans[0].0) + ), + ); + + if def_spans.len() > 2 { + let mut first = true; + for (adt_def, span) in def_spans.iter().skip(1).rev() { + let ident = tcx.item_name(*adt_def); + err.span_note( + *span, + &if first { + format!( + "`{}` contains a field of type `{}`", + tcx.type_of(def.did()), + ident + ) + } else { + format!("...which contains a field of type `{ident}`") + }, + ); + first = false; + } + } + + err.emit(); + } + } + } +} + +pub(super) fn check_packed_inner( + tcx: TyCtxt<'_>, + def_id: DefId, + stack: &mut Vec<DefId>, +) -> Option<Vec<(DefId, Span)>> { + if let ty::Adt(def, substs) = tcx.type_of(def_id).kind() { + if def.is_struct() || def.is_union() { + if def.repr().align.is_some() { + return Some(vec![(def.did(), DUMMY_SP)]); + } + + stack.push(def_id); + for field in &def.non_enum_variant().fields { + if let ty::Adt(def, _) = field.ty(tcx, substs).kind() + && !stack.contains(&def.did()) + && let Some(mut defs) = check_packed_inner(tcx, def.did(), stack) + { + defs.push((def.did(), field.ident(tcx).span)); + return Some(defs); + } + } + stack.pop(); + } + } + + None +} + +pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, adt: ty::AdtDef<'tcx>) { + if !adt.repr().transparent() { + return; + } + + if adt.is_union() && !tcx.features().transparent_unions { + feature_err( + &tcx.sess.parse_sess, + sym::transparent_unions, + sp, + "transparent unions are unstable", + ) + .emit(); + } + + if adt.variants().len() != 1 { + bad_variant_count(tcx, adt, sp, adt.did()); + if adt.variants().is_empty() { + // Don't bother checking the fields. No variants (and thus no fields) exist. + return; + } + } + + // For each field, figure out if it's known to be a ZST and align(1), with "known" + // respecting #[non_exhaustive] attributes. + let field_infos = adt.all_fields().map(|field| { + let ty = field.ty(tcx, InternalSubsts::identity_for_item(tcx, field.did)); + let param_env = tcx.param_env(field.did); + let layout = tcx.layout_of(param_env.and(ty)); + // We are currently checking the type this field came from, so it must be local + let span = tcx.hir().span_if_local(field.did).unwrap(); + let zst = layout.map_or(false, |layout| layout.is_zst()); + let align1 = layout.map_or(false, |layout| layout.align.abi.bytes() == 1); + if !zst { + return (span, zst, align1, None); + } + + fn check_non_exhaustive<'tcx>( + tcx: TyCtxt<'tcx>, + t: Ty<'tcx>, + ) -> ControlFlow<(&'static str, DefId, SubstsRef<'tcx>, bool)> { + match t.kind() { + ty::Tuple(list) => list.iter().try_for_each(|t| check_non_exhaustive(tcx, t)), + ty::Array(ty, _) => check_non_exhaustive(tcx, *ty), + ty::Adt(def, subst) => { + if !def.did().is_local() { + let non_exhaustive = def.is_variant_list_non_exhaustive() + || def + .variants() + .iter() + .any(ty::VariantDef::is_field_list_non_exhaustive); + let has_priv = def.all_fields().any(|f| !f.vis.is_public()); + if non_exhaustive || has_priv { + return ControlFlow::Break(( + def.descr(), + def.did(), + subst, + non_exhaustive, + )); + } + } + def.all_fields() + .map(|field| field.ty(tcx, subst)) + .try_for_each(|t| check_non_exhaustive(tcx, t)) + } + _ => ControlFlow::Continue(()), + } + } + + (span, zst, align1, check_non_exhaustive(tcx, ty).break_value()) + }); + + let non_zst_fields = field_infos + .clone() + .filter_map(|(span, zst, _align1, _non_exhaustive)| if !zst { Some(span) } else { None }); + let non_zst_count = non_zst_fields.clone().count(); + if non_zst_count >= 2 { + bad_non_zero_sized_fields(tcx, adt, non_zst_count, non_zst_fields, sp); + } + let incompatible_zst_fields = + field_infos.clone().filter(|(_, _, _, opt)| opt.is_some()).count(); + let incompat = incompatible_zst_fields + non_zst_count >= 2 && non_zst_count < 2; + for (span, zst, align1, non_exhaustive) in field_infos { + if zst && !align1 { + struct_span_err!( + tcx.sess, + span, + E0691, + "zero-sized field in transparent {} has alignment larger than 1", + adt.descr(), + ) + .span_label(span, "has alignment larger than 1") + .emit(); + } + if incompat && let Some((descr, def_id, substs, non_exhaustive)) = non_exhaustive { + tcx.struct_span_lint_hir( + REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS, + tcx.hir().local_def_id_to_hir_id(adt.did().expect_local()), + span, + "zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types", + |lint| { + let note = if non_exhaustive { + "is marked with `#[non_exhaustive]`" + } else { + "contains private fields" + }; + let field_ty = tcx.def_path_str_with_substs(def_id, substs); + lint + .note(format!("this {descr} contains `{field_ty}`, which {note}, \ + and makes it not a breaking change to become non-zero-sized in the future.")) + }, + ) + } + } +} + +#[allow(trivial_numeric_casts)] +fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, vs: &'tcx [hir::Variant<'tcx>], def_id: LocalDefId) { + let def = tcx.adt_def(def_id); + let sp = tcx.def_span(def_id); + def.destructor(tcx); // force the destructor to be evaluated + + if vs.is_empty() { + if let Some(attr) = tcx.get_attrs(def_id.to_def_id(), sym::repr).next() { + struct_span_err!( + tcx.sess, + attr.span, + E0084, + "unsupported representation for zero-variant enum" + ) + .span_label(sp, "zero-variant enum") + .emit(); + } + } + + let repr_type_ty = def.repr().discr_type().to_ty(tcx); + if repr_type_ty == tcx.types.i128 || repr_type_ty == tcx.types.u128 { + if !tcx.features().repr128 { + feature_err( + &tcx.sess.parse_sess, + sym::repr128, + sp, + "repr with 128-bit type is unstable", + ) + .emit(); + } + } + + for v in vs { + if let Some(ref e) = v.disr_expr { + tcx.ensure().typeck(tcx.hir().local_def_id(e.hir_id)); + } + } + + if tcx.adt_def(def_id).repr().int.is_none() { + let is_unit = |var: &hir::Variant<'_>| matches!(var.data, hir::VariantData::Unit(..)); + + let has_disr = |var: &hir::Variant<'_>| var.disr_expr.is_some(); + let has_non_units = vs.iter().any(|var| !is_unit(var)); + let disr_units = vs.iter().any(|var| is_unit(&var) && has_disr(&var)); + let disr_non_unit = vs.iter().any(|var| !is_unit(&var) && has_disr(&var)); + + if disr_non_unit || (disr_units && has_non_units) { + let mut err = + struct_span_err!(tcx.sess, sp, E0732, "`#[repr(inttype)]` must be specified"); + err.emit(); + } + } + + detect_discriminant_duplicate(tcx, def.discriminants(tcx).collect(), vs, sp); + + check_transparent(tcx, sp, def); +} + +/// Part of enum check. Given the discriminants of an enum, errors if two or more discriminants are equal +fn detect_discriminant_duplicate<'tcx>( + tcx: TyCtxt<'tcx>, + mut discrs: Vec<(VariantIdx, Discr<'tcx>)>, + vs: &'tcx [hir::Variant<'tcx>], + self_span: Span, +) { + // Helper closure to reduce duplicate code. This gets called everytime we detect a duplicate. + // Here `idx` refers to the order of which the discriminant appears, and its index in `vs` + let report = |dis: Discr<'tcx>, idx: usize, err: &mut Diagnostic| { + let var = &vs[idx]; // HIR for the duplicate discriminant + let (span, display_discr) = match var.disr_expr { + Some(ref expr) => { + // In the case the discriminant is both a duplicate and overflowed, let the user know + if let hir::ExprKind::Lit(lit) = &tcx.hir().body(expr.body).value.kind + && let rustc_ast::LitKind::Int(lit_value, _int_kind) = &lit.node + && *lit_value != dis.val + { + (tcx.hir().span(expr.hir_id), format!("`{dis}` (overflowed from `{lit_value}`)")) + // Otherwise, format the value as-is + } else { + (tcx.hir().span(expr.hir_id), format!("`{dis}`")) + } + } + None => { + // At this point we know this discriminant is a duplicate, and was not explicitly + // assigned by the user. Here we iterate backwards to fetch the HIR for the last + // explicitly assigned discriminant, and letting the user know that this was the + // increment startpoint, and how many steps from there leading to the duplicate + if let Some((n, hir::Variant { span, ident, .. })) = + vs[..idx].iter().rev().enumerate().find(|v| v.1.disr_expr.is_some()) + { + let ve_ident = var.ident; + let n = n + 1; + let sp = if n > 1 { "variants" } else { "variant" }; + + err.span_label( + *span, + format!("discriminant for `{ve_ident}` incremented from this startpoint (`{ident}` + {n} {sp} later => `{ve_ident}` = {dis})"), + ); + } + + (vs[idx].span, format!("`{dis}`")) + } + }; + + err.span_label(span, format!("{display_discr} assigned here")); + }; + + // Here we loop through the discriminants, comparing each discriminant to another. + // When a duplicate is detected, we instantiate an error and point to both + // initial and duplicate value. The duplicate discriminant is then discarded by swapping + // it with the last element and decrementing the `vec.len` (which is why we have to evaluate + // `discrs.len()` anew every iteration, and why this could be tricky to do in a functional + // style as we are mutating `discrs` on the fly). + let mut i = 0; + while i < discrs.len() { + let hir_var_i_idx = discrs[i].0.index(); + let mut error: Option<DiagnosticBuilder<'_, _>> = None; + + let mut o = i + 1; + while o < discrs.len() { + let hir_var_o_idx = discrs[o].0.index(); + + if discrs[i].1.val == discrs[o].1.val { + let err = error.get_or_insert_with(|| { + let mut ret = struct_span_err!( + tcx.sess, + self_span, + E0081, + "discriminant value `{}` assigned more than once", + discrs[i].1, + ); + + report(discrs[i].1, hir_var_i_idx, &mut ret); + + ret + }); + + report(discrs[o].1, hir_var_o_idx, err); + + // Safe to unwrap here, as we wouldn't reach this point if `discrs` was empty + discrs[o] = *discrs.last().unwrap(); + discrs.pop(); + } else { + o += 1; + } + } + + if let Some(mut e) = error { + e.emit(); + } + + i += 1; + } +} + +pub(super) fn check_type_params_are_used<'tcx>( + tcx: TyCtxt<'tcx>, + generics: &ty::Generics, + ty: Ty<'tcx>, +) { + debug!("check_type_params_are_used(generics={:?}, ty={:?})", generics, ty); + + assert_eq!(generics.parent, None); + + if generics.own_counts().types == 0 { + return; + } + + let mut params_used = BitSet::new_empty(generics.params.len()); + + if ty.references_error() { + // If there is already another error, do not emit + // an error for not using a type parameter. + assert!(tcx.sess.has_errors().is_some()); + return; + } + + for leaf in ty.walk() { + if let GenericArgKind::Type(leaf_ty) = leaf.unpack() + && let ty::Param(param) = leaf_ty.kind() + { + debug!("found use of ty param {:?}", param); + params_used.insert(param.index); + } + } + + for param in &generics.params { + if !params_used.contains(param.index) + && let ty::GenericParamDefKind::Type { .. } = param.kind + { + let span = tcx.def_span(param.def_id); + struct_span_err!( + tcx.sess, + span, + E0091, + "type parameter `{}` is unused", + param.name, + ) + .span_label(span, "unused type parameter") + .emit(); + } + } +} + +pub(super) fn check_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) { + let module = tcx.hir_module_items(module_def_id); + for id in module.items() { + check_item_type(tcx, id); + } +} + +fn async_opaque_type_cycle_error(tcx: TyCtxt<'_>, span: Span) -> ErrorGuaranteed { + struct_span_err!(tcx.sess, span, E0733, "recursion in an `async fn` requires boxing") + .span_label(span, "recursive `async fn`") + .note("a recursive `async fn` must be rewritten to return a boxed `dyn Future`") + .note( + "consider using the `async_recursion` crate: https://crates.io/crates/async_recursion", + ) + .emit() +} + +/// Emit an error for recursive opaque types. +/// +/// If this is a return `impl Trait`, find the item's return expressions and point at them. For +/// direct recursion this is enough, but for indirect recursion also point at the last intermediary +/// `impl Trait`. +/// +/// If all the return expressions evaluate to `!`, then we explain that the error will go away +/// after changing it. This can happen when a user uses `panic!()` or similar as a placeholder. +fn opaque_type_cycle_error(tcx: TyCtxt<'_>, def_id: LocalDefId, span: Span) -> ErrorGuaranteed { + let mut err = struct_span_err!(tcx.sess, span, E0720, "cannot resolve opaque type"); + + let mut label = false; + if let Some((def_id, visitor)) = get_owner_return_paths(tcx, def_id) { + let typeck_results = tcx.typeck(def_id); + if visitor + .returns + .iter() + .filter_map(|expr| typeck_results.node_type_opt(expr.hir_id)) + .all(|ty| matches!(ty.kind(), ty::Never)) + { + let spans = visitor + .returns + .iter() + .filter(|expr| typeck_results.node_type_opt(expr.hir_id).is_some()) + .map(|expr| expr.span) + .collect::<Vec<Span>>(); + let span_len = spans.len(); + if span_len == 1 { + err.span_label(spans[0], "this returned value is of `!` type"); + } else { + let mut multispan: MultiSpan = spans.clone().into(); + for span in spans { + multispan.push_span_label(span, "this returned value is of `!` type"); + } + err.span_note(multispan, "these returned values have a concrete \"never\" type"); + } + err.help("this error will resolve once the item's body returns a concrete type"); + } else { + let mut seen = FxHashSet::default(); + seen.insert(span); + err.span_label(span, "recursive opaque type"); + label = true; + for (sp, ty) in visitor + .returns + .iter() + .filter_map(|e| typeck_results.node_type_opt(e.hir_id).map(|t| (e.span, t))) + .filter(|(_, ty)| !matches!(ty.kind(), ty::Never)) + { + struct OpaqueTypeCollector(Vec<DefId>); + impl<'tcx> ty::visit::TypeVisitor<'tcx> for OpaqueTypeCollector { + fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { + match *t.kind() { + ty::Opaque(def, _) => { + self.0.push(def); + ControlFlow::CONTINUE + } + _ => t.super_visit_with(self), + } + } + } + let mut visitor = OpaqueTypeCollector(vec![]); + ty.visit_with(&mut visitor); + for def_id in visitor.0 { + let ty_span = tcx.def_span(def_id); + if !seen.contains(&ty_span) { + err.span_label(ty_span, &format!("returning this opaque type `{ty}`")); + seen.insert(ty_span); + } + err.span_label(sp, &format!("returning here with type `{ty}`")); + } + } + } + } + if !label { + err.span_label(span, "cannot resolve opaque type"); + } + err.emit() +} diff --git a/compiler/rustc_hir_analysis/src/check/compare_method.rs b/compiler/rustc_hir_analysis/src/check/compare_method.rs new file mode 100644 index 000000000..32f66b06f --- /dev/null +++ b/compiler/rustc_hir_analysis/src/check/compare_method.rs @@ -0,0 +1,1825 @@ +use super::potentially_plural_count; +use crate::errors::LifetimesOrBoundsMismatchOnTrait; +use hir::def_id::{DefId, LocalDefId}; +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticId, ErrorGuaranteed}; +use rustc_hir as hir; +use rustc_hir::def::{DefKind, Res}; +use rustc_hir::intravisit; +use rustc_hir::{GenericParamKind, ImplItemKind, TraitItemKind}; +use rustc_infer::infer::outlives::env::OutlivesEnvironment; +use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; +use rustc_infer::infer::{self, TyCtxtInferExt}; +use rustc_infer::traits::util; +use rustc_middle::ty::error::{ExpectedFound, TypeError}; +use rustc_middle::ty::util::ExplicitSelf; +use rustc_middle::ty::InternalSubsts; +use rustc_middle::ty::{ + self, AssocItem, DefIdTree, Ty, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitable, +}; +use rustc_middle::ty::{GenericParamDefKind, ToPredicate, TyCtxt}; +use rustc_span::Span; +use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt; +use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _; +use rustc_trait_selection::traits::{ + self, ObligationCause, ObligationCauseCode, ObligationCtxt, Reveal, +}; +use std::iter; + +/// Checks that a method from an impl conforms to the signature of +/// the same method as declared in the trait. +/// +/// # Parameters +/// +/// - `impl_m`: type of the method we are checking +/// - `impl_m_span`: span to use for reporting errors +/// - `trait_m`: the method in the trait +/// - `impl_trait_ref`: the TraitRef corresponding to the trait implementation +pub(crate) fn compare_impl_method<'tcx>( + tcx: TyCtxt<'tcx>, + impl_m: &ty::AssocItem, + trait_m: &ty::AssocItem, + impl_trait_ref: ty::TraitRef<'tcx>, + trait_item_span: Option<Span>, +) { + debug!("compare_impl_method(impl_trait_ref={:?})", impl_trait_ref); + + let impl_m_span = tcx.def_span(impl_m.def_id); + + if let Err(_) = compare_self_type(tcx, impl_m, impl_m_span, trait_m, impl_trait_ref) { + return; + } + + if let Err(_) = compare_number_of_generics(tcx, impl_m, impl_m_span, trait_m, trait_item_span) { + return; + } + + if let Err(_) = compare_generic_param_kinds(tcx, impl_m, trait_m) { + return; + } + + if let Err(_) = + compare_number_of_method_arguments(tcx, impl_m, impl_m_span, trait_m, trait_item_span) + { + return; + } + + if let Err(_) = compare_synthetic_generics(tcx, impl_m, trait_m) { + return; + } + + if let Err(_) = compare_predicate_entailment(tcx, impl_m, impl_m_span, trait_m, impl_trait_ref) + { + return; + } +} + +/// This function is best explained by example. Consider a trait: +/// +/// trait Trait<'t, T> { +/// // `trait_m` +/// fn method<'a, M>(t: &'t T, m: &'a M) -> Self; +/// } +/// +/// And an impl: +/// +/// impl<'i, 'j, U> Trait<'j, &'i U> for Foo { +/// // `impl_m` +/// fn method<'b, N>(t: &'j &'i U, m: &'b N) -> Foo; +/// } +/// +/// We wish to decide if those two method types are compatible. +/// For this we have to show that, assuming the bounds of the impl hold, the +/// bounds of `trait_m` imply the bounds of `impl_m`. +/// +/// We start out with `trait_to_impl_substs`, that maps the trait +/// type parameters to impl type parameters. This is taken from the +/// impl trait reference: +/// +/// trait_to_impl_substs = {'t => 'j, T => &'i U, Self => Foo} +/// +/// We create a mapping `dummy_substs` that maps from the impl type +/// parameters to fresh types and regions. For type parameters, +/// this is the identity transform, but we could as well use any +/// placeholder types. For regions, we convert from bound to free +/// regions (Note: but only early-bound regions, i.e., those +/// declared on the impl or used in type parameter bounds). +/// +/// impl_to_placeholder_substs = {'i => 'i0, U => U0, N => N0 } +/// +/// Now we can apply `placeholder_substs` to the type of the impl method +/// to yield a new function type in terms of our fresh, placeholder +/// types: +/// +/// <'b> fn(t: &'i0 U0, m: &'b) -> Foo +/// +/// We now want to extract and substitute the type of the *trait* +/// method and compare it. To do so, we must create a compound +/// substitution by combining `trait_to_impl_substs` and +/// `impl_to_placeholder_substs`, and also adding a mapping for the method +/// type parameters. We extend the mapping to also include +/// the method parameters. +/// +/// trait_to_placeholder_substs = { T => &'i0 U0, Self => Foo, M => N0 } +/// +/// Applying this to the trait method type yields: +/// +/// <'a> fn(t: &'i0 U0, m: &'a) -> Foo +/// +/// This type is also the same but the name of the bound region (`'a` +/// vs `'b`). However, the normal subtyping rules on fn types handle +/// this kind of equivalency just fine. +/// +/// We now use these substitutions to ensure that all declared bounds are +/// satisfied by the implementation's method. +/// +/// We do this by creating a parameter environment which contains a +/// substitution corresponding to `impl_to_placeholder_substs`. We then build +/// `trait_to_placeholder_substs` and use it to convert the predicates contained +/// in the `trait_m` generics to the placeholder form. +/// +/// Finally we register each of these predicates as an obligation and check that +/// they hold. +#[instrument(level = "debug", skip(tcx, impl_m_span, impl_trait_ref))] +fn compare_predicate_entailment<'tcx>( + tcx: TyCtxt<'tcx>, + impl_m: &AssocItem, + impl_m_span: Span, + trait_m: &AssocItem, + impl_trait_ref: ty::TraitRef<'tcx>, +) -> Result<(), ErrorGuaranteed> { + let trait_to_impl_substs = impl_trait_ref.substs; + + // This node-id should be used for the `body_id` field on each + // `ObligationCause` (and the `FnCtxt`). + // + // FIXME(@lcnr): remove that after removing `cause.body_id` from + // obligations. + let impl_m_hir_id = tcx.hir().local_def_id_to_hir_id(impl_m.def_id.expect_local()); + // We sometimes modify the span further down. + let mut cause = ObligationCause::new( + impl_m_span, + impl_m_hir_id, + ObligationCauseCode::CompareImplItemObligation { + impl_item_def_id: impl_m.def_id.expect_local(), + trait_item_def_id: trait_m.def_id, + kind: impl_m.kind, + }, + ); + + // Create mapping from impl to placeholder. + let impl_to_placeholder_substs = InternalSubsts::identity_for_item(tcx, impl_m.def_id); + + // Create mapping from trait to placeholder. + let trait_to_placeholder_substs = + impl_to_placeholder_substs.rebase_onto(tcx, impl_m.container_id(tcx), trait_to_impl_substs); + debug!("compare_impl_method: trait_to_placeholder_substs={:?}", trait_to_placeholder_substs); + + let impl_m_generics = tcx.generics_of(impl_m.def_id); + let trait_m_generics = tcx.generics_of(trait_m.def_id); + let impl_m_predicates = tcx.predicates_of(impl_m.def_id); + let trait_m_predicates = tcx.predicates_of(trait_m.def_id); + + // Check region bounds. + check_region_bounds_on_impl_item(tcx, impl_m, trait_m, &trait_m_generics, &impl_m_generics)?; + + // Create obligations for each predicate declared by the impl + // definition in the context of the trait's parameter + // environment. We can't just use `impl_env.caller_bounds`, + // however, because we want to replace all late-bound regions with + // region variables. + let impl_predicates = tcx.predicates_of(impl_m_predicates.parent.unwrap()); + let mut hybrid_preds = impl_predicates.instantiate_identity(tcx); + + debug!("compare_impl_method: impl_bounds={:?}", hybrid_preds); + + // This is the only tricky bit of the new way we check implementation methods + // We need to build a set of predicates where only the method-level bounds + // are from the trait and we assume all other bounds from the implementation + // to be previously satisfied. + // + // We then register the obligations from the impl_m and check to see + // if all constraints hold. + hybrid_preds + .predicates + .extend(trait_m_predicates.instantiate_own(tcx, trait_to_placeholder_substs).predicates); + + // Construct trait parameter environment and then shift it into the placeholder viewpoint. + // The key step here is to update the caller_bounds's predicates to be + // the new hybrid bounds we computed. + let normalize_cause = traits::ObligationCause::misc(impl_m_span, impl_m_hir_id); + let param_env = ty::ParamEnv::new( + tcx.intern_predicates(&hybrid_preds.predicates), + Reveal::UserFacing, + hir::Constness::NotConst, + ); + let param_env = traits::normalize_param_env_or_error(tcx, param_env, normalize_cause); + + let infcx = &tcx.infer_ctxt().build(); + let ocx = ObligationCtxt::new(infcx); + + debug!("compare_impl_method: caller_bounds={:?}", param_env.caller_bounds()); + + let mut selcx = traits::SelectionContext::new(&infcx); + let impl_m_own_bounds = impl_m_predicates.instantiate_own(tcx, impl_to_placeholder_substs); + for (predicate, span) in iter::zip(impl_m_own_bounds.predicates, impl_m_own_bounds.spans) { + let normalize_cause = traits::ObligationCause::misc(span, impl_m_hir_id); + let traits::Normalized { value: predicate, obligations } = + traits::normalize(&mut selcx, param_env, normalize_cause, predicate); + + ocx.register_obligations(obligations); + let cause = ObligationCause::new( + span, + impl_m_hir_id, + ObligationCauseCode::CompareImplItemObligation { + impl_item_def_id: impl_m.def_id.expect_local(), + trait_item_def_id: trait_m.def_id, + kind: impl_m.kind, + }, + ); + ocx.register_obligation(traits::Obligation::new(cause, param_env, predicate)); + } + + // We now need to check that the signature of the impl method is + // compatible with that of the trait method. We do this by + // checking that `impl_fty <: trait_fty`. + // + // FIXME. Unfortunately, this doesn't quite work right now because + // associated type normalization is not integrated into subtype + // checks. For the comparison to be valid, we need to + // normalize the associated types in the impl/trait methods + // first. However, because function types bind regions, just + // calling `normalize_associated_types_in` would have no effect on + // any associated types appearing in the fn arguments or return + // type. + + // Compute placeholder form of impl and trait method tys. + let tcx = infcx.tcx; + + let mut wf_tys = FxHashSet::default(); + + let impl_sig = infcx.replace_bound_vars_with_fresh_vars( + impl_m_span, + infer::HigherRankedType, + tcx.fn_sig(impl_m.def_id), + ); + + let norm_cause = ObligationCause::misc(impl_m_span, impl_m_hir_id); + let impl_sig = ocx.normalize(norm_cause.clone(), param_env, impl_sig); + let impl_fty = tcx.mk_fn_ptr(ty::Binder::dummy(impl_sig)); + debug!("compare_impl_method: impl_fty={:?}", impl_fty); + + let trait_sig = tcx.bound_fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs); + let trait_sig = tcx.liberate_late_bound_regions(impl_m.def_id, trait_sig); + + // Next, add all inputs and output as well-formed tys. Importantly, + // we have to do this before normalization, since the normalized ty may + // not contain the input parameters. See issue #87748. + wf_tys.extend(trait_sig.inputs_and_output.iter()); + let trait_sig = ocx.normalize(norm_cause, param_env, trait_sig); + // We also have to add the normalized trait signature + // as we don't normalize during implied bounds computation. + wf_tys.extend(trait_sig.inputs_and_output.iter()); + let trait_fty = tcx.mk_fn_ptr(ty::Binder::dummy(trait_sig)); + + debug!("compare_impl_method: trait_fty={:?}", trait_fty); + + // FIXME: We'd want to keep more accurate spans than "the method signature" when + // processing the comparison between the trait and impl fn, but we sadly lose them + // and point at the whole signature when a trait bound or specific input or output + // type would be more appropriate. In other places we have a `Vec<Span>` + // corresponding to their `Vec<Predicate>`, but we don't have that here. + // Fixing this would improve the output of test `issue-83765.rs`. + let mut result = infcx + .at(&cause, param_env) + .sup(trait_fty, impl_fty) + .map(|infer_ok| ocx.register_infer_ok_obligations(infer_ok)); + + // HACK(RPITIT): #101614. When we are trying to infer the hidden types for + // RPITITs, we need to equate the output tys instead of just subtyping. If + // we just use `sup` above, we'll end up `&'static str <: _#1t`, which causes + // us to infer `_#1t = #'_#2r str`, where `'_#2r` is unconstrained, which gets + // fixed up to `ReEmpty`, and which is certainly not what we want. + if trait_fty.has_infer_types() { + result = result.and_then(|()| { + infcx + .at(&cause, param_env) + .eq(trait_sig.output(), impl_sig.output()) + .map(|infer_ok| ocx.register_infer_ok_obligations(infer_ok)) + }); + } + + if let Err(terr) = result { + debug!("sub_types failed: impl ty {:?}, trait ty {:?}", impl_fty, trait_fty); + + let (impl_err_span, trait_err_span) = + extract_spans_for_error_reporting(&infcx, terr, &cause, impl_m, trait_m); + + cause.span = impl_err_span; + + let mut diag = struct_span_err!( + tcx.sess, + cause.span(), + E0053, + "method `{}` has an incompatible type for trait", + trait_m.name + ); + match &terr { + TypeError::ArgumentMutability(0) | TypeError::ArgumentSorts(_, 0) + if trait_m.fn_has_self_parameter => + { + let ty = trait_sig.inputs()[0]; + let sugg = match ExplicitSelf::determine(ty, |_| ty == impl_trait_ref.self_ty()) { + ExplicitSelf::ByValue => "self".to_owned(), + ExplicitSelf::ByReference(_, hir::Mutability::Not) => "&self".to_owned(), + ExplicitSelf::ByReference(_, hir::Mutability::Mut) => "&mut self".to_owned(), + _ => format!("self: {ty}"), + }; + + // When the `impl` receiver is an arbitrary self type, like `self: Box<Self>`, the + // span points only at the type `Box<Self`>, but we want to cover the whole + // argument pattern and type. + let span = match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind { + ImplItemKind::Fn(ref sig, body) => tcx + .hir() + .body_param_names(body) + .zip(sig.decl.inputs.iter()) + .map(|(param, ty)| param.span.to(ty.span)) + .next() + .unwrap_or(impl_err_span), + _ => bug!("{:?} is not a method", impl_m), + }; + + diag.span_suggestion( + span, + "change the self-receiver type to match the trait", + sugg, + Applicability::MachineApplicable, + ); + } + TypeError::ArgumentMutability(i) | TypeError::ArgumentSorts(_, i) => { + if trait_sig.inputs().len() == *i { + // Suggestion to change output type. We do not suggest in `async` functions + // to avoid complex logic or incorrect output. + match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind { + ImplItemKind::Fn(ref sig, _) + if sig.header.asyncness == hir::IsAsync::NotAsync => + { + let msg = "change the output type to match the trait"; + let ap = Applicability::MachineApplicable; + match sig.decl.output { + hir::FnRetTy::DefaultReturn(sp) => { + let sugg = format!("-> {} ", trait_sig.output()); + diag.span_suggestion_verbose(sp, msg, sugg, ap); + } + hir::FnRetTy::Return(hir_ty) => { + let sugg = trait_sig.output(); + diag.span_suggestion(hir_ty.span, msg, sugg, ap); + } + }; + } + _ => {} + }; + } else if let Some(trait_ty) = trait_sig.inputs().get(*i) { + diag.span_suggestion( + impl_err_span, + "change the parameter type to match the trait", + trait_ty, + Applicability::MachineApplicable, + ); + } + } + _ => {} + } + + infcx.err_ctxt().note_type_err( + &mut diag, + &cause, + trait_err_span.map(|sp| (sp, "type in trait".to_owned())), + Some(infer::ValuePairs::Terms(ExpectedFound { + expected: trait_fty.into(), + found: impl_fty.into(), + })), + terr, + false, + false, + ); + + return Err(diag.emit()); + } + + // Check that all obligations are satisfied by the implementation's + // version. + let errors = ocx.select_all_or_error(); + if !errors.is_empty() { + let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); + return Err(reported); + } + + // Finally, resolve all regions. This catches wily misuses of + // lifetime parameters. + let outlives_environment = OutlivesEnvironment::with_bounds( + param_env, + Some(infcx), + infcx.implied_bounds_tys(param_env, impl_m_hir_id, wf_tys), + ); + infcx.check_region_obligations_and_report_errors( + impl_m.def_id.expect_local(), + &outlives_environment, + ); + + Ok(()) +} + +pub fn collect_trait_impl_trait_tys<'tcx>( + tcx: TyCtxt<'tcx>, + def_id: DefId, +) -> Result<&'tcx FxHashMap<DefId, Ty<'tcx>>, ErrorGuaranteed> { + let impl_m = tcx.opt_associated_item(def_id).unwrap(); + let trait_m = tcx.opt_associated_item(impl_m.trait_item_def_id.unwrap()).unwrap(); + let impl_trait_ref = tcx.impl_trait_ref(impl_m.impl_container(tcx).unwrap()).unwrap(); + let param_env = tcx.param_env(def_id); + + let trait_to_impl_substs = impl_trait_ref.substs; + + let impl_m_hir_id = tcx.hir().local_def_id_to_hir_id(impl_m.def_id.expect_local()); + let return_span = tcx.hir().fn_decl_by_hir_id(impl_m_hir_id).unwrap().output.span(); + let cause = ObligationCause::new( + return_span, + impl_m_hir_id, + ObligationCauseCode::CompareImplItemObligation { + impl_item_def_id: impl_m.def_id.expect_local(), + trait_item_def_id: trait_m.def_id, + kind: impl_m.kind, + }, + ); + + // Create mapping from impl to placeholder. + let impl_to_placeholder_substs = InternalSubsts::identity_for_item(tcx, impl_m.def_id); + + // Create mapping from trait to placeholder. + let trait_to_placeholder_substs = + impl_to_placeholder_substs.rebase_onto(tcx, impl_m.container_id(tcx), trait_to_impl_substs); + + let infcx = &tcx.infer_ctxt().build(); + let ocx = ObligationCtxt::new(infcx); + + let norm_cause = ObligationCause::misc(return_span, impl_m_hir_id); + let impl_sig = ocx.normalize( + norm_cause.clone(), + param_env, + infcx.replace_bound_vars_with_fresh_vars( + return_span, + infer::HigherRankedType, + tcx.fn_sig(impl_m.def_id), + ), + ); + let impl_return_ty = impl_sig.output(); + + let mut collector = ImplTraitInTraitCollector::new(&ocx, return_span, param_env, impl_m_hir_id); + let unnormalized_trait_sig = tcx + .liberate_late_bound_regions( + impl_m.def_id, + tcx.bound_fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs), + ) + .fold_with(&mut collector); + let trait_sig = ocx.normalize(norm_cause.clone(), param_env, unnormalized_trait_sig); + let trait_return_ty = trait_sig.output(); + + let wf_tys = FxHashSet::from_iter( + unnormalized_trait_sig.inputs_and_output.iter().chain(trait_sig.inputs_and_output.iter()), + ); + + match infcx.at(&cause, param_env).eq(trait_return_ty, impl_return_ty) { + Ok(infer::InferOk { value: (), obligations }) => { + ocx.register_obligations(obligations); + } + Err(terr) => { + let mut diag = struct_span_err!( + tcx.sess, + cause.span(), + E0053, + "method `{}` has an incompatible return type for trait", + trait_m.name + ); + let hir = tcx.hir(); + infcx.err_ctxt().note_type_err( + &mut diag, + &cause, + hir.get_if_local(impl_m.def_id) + .and_then(|node| node.fn_decl()) + .map(|decl| (decl.output.span(), "return type in trait".to_owned())), + Some(infer::ValuePairs::Terms(ExpectedFound { + expected: trait_return_ty.into(), + found: impl_return_ty.into(), + })), + terr, + false, + false, + ); + return Err(diag.emit()); + } + } + + // Unify the whole function signature. We need to do this to fully infer + // the lifetimes of the return type, but do this after unifying just the + // return types, since we want to avoid duplicating errors from + // `compare_predicate_entailment`. + match infcx + .at(&cause, param_env) + .eq(tcx.mk_fn_ptr(ty::Binder::dummy(trait_sig)), tcx.mk_fn_ptr(ty::Binder::dummy(impl_sig))) + { + Ok(infer::InferOk { value: (), obligations }) => { + ocx.register_obligations(obligations); + } + Err(terr) => { + let guar = tcx.sess.delay_span_bug( + return_span, + format!("could not unify `{trait_sig}` and `{impl_sig}`: {terr:?}"), + ); + return Err(guar); + } + } + + // Check that all obligations are satisfied by the implementation's + // RPITs. + let errors = ocx.select_all_or_error(); + if !errors.is_empty() { + let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); + return Err(reported); + } + + // Finally, resolve all regions. This catches wily misuses of + // lifetime parameters. + let outlives_environment = OutlivesEnvironment::with_bounds( + param_env, + Some(infcx), + infcx.implied_bounds_tys(param_env, impl_m_hir_id, wf_tys), + ); + infcx.check_region_obligations_and_report_errors( + impl_m.def_id.expect_local(), + &outlives_environment, + ); + + let mut collected_tys = FxHashMap::default(); + for (def_id, (ty, substs)) in collector.types { + match infcx.fully_resolve(ty) { + Ok(ty) => { + // `ty` contains free regions that we created earlier while liberating the + // trait fn signature. However, projection normalization expects `ty` to + // contains `def_id`'s early-bound regions. + let id_substs = InternalSubsts::identity_for_item(tcx, def_id); + debug!(?id_substs, ?substs); + let map: FxHashMap<ty::GenericArg<'tcx>, ty::GenericArg<'tcx>> = + std::iter::zip(substs, id_substs).collect(); + debug!(?map); + + // NOTE(compiler-errors): RPITITs, like all other RPITs, have early-bound + // region substs that are synthesized during AST lowering. These are substs + // that are appended to the parent substs (trait and trait method). However, + // we're trying to infer the unsubstituted type value of the RPITIT inside + // the *impl*, so we can later use the impl's method substs to normalize + // an RPITIT to a concrete type (`confirm_impl_trait_in_trait_candidate`). + // + // Due to the design of RPITITs, during AST lowering, we have no idea that + // an impl method corresponds to a trait method with RPITITs in it. Therefore, + // we don't have a list of early-bound region substs for the RPITIT in the impl. + // Since early region parameters are index-based, we can't just rebase these + // (trait method) early-bound region substs onto the impl, and there's no + // guarantee that the indices from the trait substs and impl substs line up. + // So to fix this, we subtract the number of trait substs and add the number of + // impl substs to *renumber* these early-bound regions to their corresponding + // indices in the impl's substitutions list. + // + // Also, we only need to account for a difference in trait and impl substs, + // since we previously enforce that the trait method and impl method have the + // same generics. + let num_trait_substs = trait_to_impl_substs.len(); + let num_impl_substs = tcx.generics_of(impl_m.container_id(tcx)).params.len(); + let ty = tcx.fold_regions(ty, |region, _| { + let (ty::ReFree(_) | ty::ReEarlyBound(_)) = region.kind() else { return region; }; + let Some(ty::ReEarlyBound(e)) = map.get(®ion.into()).map(|r| r.expect_region().kind()) + else { + tcx + .sess + .delay_span_bug( + return_span, + "expected ReFree to map to ReEarlyBound" + ); + return tcx.lifetimes.re_static; + }; + tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion { + def_id: e.def_id, + name: e.name, + index: (e.index as usize - num_trait_substs + num_impl_substs) as u32, + })) + }); + debug!(%ty); + collected_tys.insert(def_id, ty); + } + Err(err) => { + tcx.sess.delay_span_bug( + return_span, + format!("could not fully resolve: {ty} => {err:?}"), + ); + collected_tys.insert(def_id, tcx.ty_error()); + } + } + } + + Ok(&*tcx.arena.alloc(collected_tys)) +} + +struct ImplTraitInTraitCollector<'a, 'tcx> { + ocx: &'a ObligationCtxt<'a, 'tcx>, + types: FxHashMap<DefId, (Ty<'tcx>, ty::SubstsRef<'tcx>)>, + span: Span, + param_env: ty::ParamEnv<'tcx>, + body_id: hir::HirId, +} + +impl<'a, 'tcx> ImplTraitInTraitCollector<'a, 'tcx> { + fn new( + ocx: &'a ObligationCtxt<'a, 'tcx>, + span: Span, + param_env: ty::ParamEnv<'tcx>, + body_id: hir::HirId, + ) -> Self { + ImplTraitInTraitCollector { ocx, types: FxHashMap::default(), span, param_env, body_id } + } +} + +impl<'tcx> TypeFolder<'tcx> for ImplTraitInTraitCollector<'_, 'tcx> { + fn tcx<'a>(&'a self) -> TyCtxt<'tcx> { + self.ocx.infcx.tcx + } + + fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { + if let ty::Projection(proj) = ty.kind() + && self.tcx().def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder + { + if let Some((ty, _)) = self.types.get(&proj.item_def_id) { + return *ty; + } + //FIXME(RPITIT): Deny nested RPITIT in substs too + if proj.substs.has_escaping_bound_vars() { + bug!("FIXME(RPITIT): error here"); + } + // Replace with infer var + let infer_ty = self.ocx.infcx.next_ty_var(TypeVariableOrigin { + span: self.span, + kind: TypeVariableOriginKind::MiscVariable, + }); + self.types.insert(proj.item_def_id, (infer_ty, proj.substs)); + // Recurse into bounds + for (pred, pred_span) in self.tcx().bound_explicit_item_bounds(proj.item_def_id).subst_iter_copied(self.tcx(), proj.substs) { + let pred = pred.fold_with(self); + let pred = self.ocx.normalize( + ObligationCause::misc(self.span, self.body_id), + self.param_env, + pred, + ); + + self.ocx.register_obligation(traits::Obligation::new( + ObligationCause::new( + self.span, + self.body_id, + ObligationCauseCode::BindingObligation(proj.item_def_id, pred_span), + ), + self.param_env, + pred, + )); + } + infer_ty + } else { + ty.super_fold_with(self) + } + } +} + +fn check_region_bounds_on_impl_item<'tcx>( + tcx: TyCtxt<'tcx>, + impl_m: &ty::AssocItem, + trait_m: &ty::AssocItem, + trait_generics: &ty::Generics, + impl_generics: &ty::Generics, +) -> Result<(), ErrorGuaranteed> { + let trait_params = trait_generics.own_counts().lifetimes; + let impl_params = impl_generics.own_counts().lifetimes; + + debug!( + "check_region_bounds_on_impl_item: \ + trait_generics={:?} \ + impl_generics={:?}", + trait_generics, impl_generics + ); + + // Must have same number of early-bound lifetime parameters. + // Unfortunately, if the user screws up the bounds, then this + // will change classification between early and late. E.g., + // if in trait we have `<'a,'b:'a>`, and in impl we just have + // `<'a,'b>`, then we have 2 early-bound lifetime parameters + // in trait but 0 in the impl. But if we report "expected 2 + // but found 0" it's confusing, because it looks like there + // are zero. Since I don't quite know how to phrase things at + // the moment, give a kind of vague error message. + if trait_params != impl_params { + let span = tcx + .hir() + .get_generics(impl_m.def_id.expect_local()) + .expect("expected impl item to have generics or else we can't compare them") + .span; + let generics_span = if let Some(local_def_id) = trait_m.def_id.as_local() { + Some( + tcx.hir() + .get_generics(local_def_id) + .expect("expected trait item to have generics or else we can't compare them") + .span, + ) + } else { + None + }; + + let reported = tcx.sess.emit_err(LifetimesOrBoundsMismatchOnTrait { + span, + item_kind: assoc_item_kind_str(impl_m), + ident: impl_m.ident(tcx), + generics_span, + }); + return Err(reported); + } + + Ok(()) +} + +#[instrument(level = "debug", skip(infcx))] +fn extract_spans_for_error_reporting<'tcx>( + infcx: &infer::InferCtxt<'tcx>, + terr: TypeError<'_>, + cause: &ObligationCause<'tcx>, + impl_m: &ty::AssocItem, + trait_m: &ty::AssocItem, +) -> (Span, Option<Span>) { + let tcx = infcx.tcx; + let mut impl_args = match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind { + ImplItemKind::Fn(ref sig, _) => { + sig.decl.inputs.iter().map(|t| t.span).chain(iter::once(sig.decl.output.span())) + } + _ => bug!("{:?} is not a method", impl_m), + }; + let trait_args = + trait_m.def_id.as_local().map(|def_id| match tcx.hir().expect_trait_item(def_id).kind { + TraitItemKind::Fn(ref sig, _) => { + sig.decl.inputs.iter().map(|t| t.span).chain(iter::once(sig.decl.output.span())) + } + _ => bug!("{:?} is not a TraitItemKind::Fn", trait_m), + }); + + match terr { + TypeError::ArgumentMutability(i) => { + (impl_args.nth(i).unwrap(), trait_args.and_then(|mut args| args.nth(i))) + } + TypeError::ArgumentSorts(ExpectedFound { .. }, i) => { + (impl_args.nth(i).unwrap(), trait_args.and_then(|mut args| args.nth(i))) + } + _ => (cause.span(), tcx.hir().span_if_local(trait_m.def_id)), + } +} + +fn compare_self_type<'tcx>( + tcx: TyCtxt<'tcx>, + impl_m: &ty::AssocItem, + impl_m_span: Span, + trait_m: &ty::AssocItem, + impl_trait_ref: ty::TraitRef<'tcx>, +) -> Result<(), ErrorGuaranteed> { + // Try to give more informative error messages about self typing + // mismatches. Note that any mismatch will also be detected + // below, where we construct a canonical function type that + // includes the self parameter as a normal parameter. It's just + // that the error messages you get out of this code are a bit more + // inscrutable, particularly for cases where one method has no + // self. + + let self_string = |method: &ty::AssocItem| { + let untransformed_self_ty = match method.container { + ty::ImplContainer => impl_trait_ref.self_ty(), + ty::TraitContainer => tcx.types.self_param, + }; + let self_arg_ty = tcx.fn_sig(method.def_id).input(0); + let param_env = ty::ParamEnv::reveal_all(); + + let infcx = tcx.infer_ctxt().build(); + let self_arg_ty = tcx.liberate_late_bound_regions(method.def_id, self_arg_ty); + let can_eq_self = |ty| infcx.can_eq(param_env, untransformed_self_ty, ty).is_ok(); + match ExplicitSelf::determine(self_arg_ty, can_eq_self) { + ExplicitSelf::ByValue => "self".to_owned(), + ExplicitSelf::ByReference(_, hir::Mutability::Not) => "&self".to_owned(), + ExplicitSelf::ByReference(_, hir::Mutability::Mut) => "&mut self".to_owned(), + _ => format!("self: {self_arg_ty}"), + } + }; + + match (trait_m.fn_has_self_parameter, impl_m.fn_has_self_parameter) { + (false, false) | (true, true) => {} + + (false, true) => { + let self_descr = self_string(impl_m); + let mut err = struct_span_err!( + tcx.sess, + impl_m_span, + E0185, + "method `{}` has a `{}` declaration in the impl, but not in the trait", + trait_m.name, + self_descr + ); + err.span_label(impl_m_span, format!("`{self_descr}` used in impl")); + if let Some(span) = tcx.hir().span_if_local(trait_m.def_id) { + err.span_label(span, format!("trait method declared without `{self_descr}`")); + } else { + err.note_trait_signature(trait_m.name, trait_m.signature(tcx)); + } + let reported = err.emit(); + return Err(reported); + } + + (true, false) => { + let self_descr = self_string(trait_m); + let mut err = struct_span_err!( + tcx.sess, + impl_m_span, + E0186, + "method `{}` has a `{}` declaration in the trait, but not in the impl", + trait_m.name, + self_descr + ); + err.span_label(impl_m_span, format!("expected `{self_descr}` in impl")); + if let Some(span) = tcx.hir().span_if_local(trait_m.def_id) { + err.span_label(span, format!("`{self_descr}` used in trait")); + } else { + err.note_trait_signature(trait_m.name, trait_m.signature(tcx)); + } + let reported = err.emit(); + return Err(reported); + } + } + + Ok(()) +} + +/// Checks that the number of generics on a given assoc item in a trait impl is the same +/// as the number of generics on the respective assoc item in the trait definition. +/// +/// For example this code emits the errors in the following code: +/// ``` +/// trait Trait { +/// fn foo(); +/// type Assoc<T>; +/// } +/// +/// impl Trait for () { +/// fn foo<T>() {} +/// //~^ error +/// type Assoc = u32; +/// //~^ error +/// } +/// ``` +/// +/// Notably this does not error on `foo<T>` implemented as `foo<const N: u8>` or +/// `foo<const N: u8>` implemented as `foo<const N: u32>`. This is handled in +/// [`compare_generic_param_kinds`]. This function also does not handle lifetime parameters +fn compare_number_of_generics<'tcx>( + tcx: TyCtxt<'tcx>, + impl_: &ty::AssocItem, + _impl_span: Span, + trait_: &ty::AssocItem, + trait_span: Option<Span>, +) -> Result<(), ErrorGuaranteed> { + let trait_own_counts = tcx.generics_of(trait_.def_id).own_counts(); + let impl_own_counts = tcx.generics_of(impl_.def_id).own_counts(); + + // This avoids us erroring on `foo<T>` implemented as `foo<const N: u8>` as this is implemented + // in `compare_generic_param_kinds` which will give a nicer error message than something like: + // "expected 1 type parameter, found 0 type parameters" + if (trait_own_counts.types + trait_own_counts.consts) + == (impl_own_counts.types + impl_own_counts.consts) + { + return Ok(()); + } + + let matchings = [ + ("type", trait_own_counts.types, impl_own_counts.types), + ("const", trait_own_counts.consts, impl_own_counts.consts), + ]; + + let item_kind = assoc_item_kind_str(impl_); + + let mut err_occurred = None; + for (kind, trait_count, impl_count) in matchings { + if impl_count != trait_count { + let arg_spans = |kind: ty::AssocKind, generics: &hir::Generics<'_>| { + let mut spans = generics + .params + .iter() + .filter(|p| match p.kind { + hir::GenericParamKind::Lifetime { + kind: hir::LifetimeParamKind::Elided, + } => { + // A fn can have an arbitrary number of extra elided lifetimes for the + // same signature. + !matches!(kind, ty::AssocKind::Fn) + } + _ => true, + }) + .map(|p| p.span) + .collect::<Vec<Span>>(); + if spans.is_empty() { + spans = vec![generics.span] + } + spans + }; + let (trait_spans, impl_trait_spans) = if let Some(def_id) = trait_.def_id.as_local() { + let trait_item = tcx.hir().expect_trait_item(def_id); + let arg_spans: Vec<Span> = arg_spans(trait_.kind, trait_item.generics); + let impl_trait_spans: Vec<Span> = trait_item + .generics + .params + .iter() + .filter_map(|p| match p.kind { + GenericParamKind::Type { synthetic: true, .. } => Some(p.span), + _ => None, + }) + .collect(); + (Some(arg_spans), impl_trait_spans) + } else { + (trait_span.map(|s| vec![s]), vec![]) + }; + + let impl_item = tcx.hir().expect_impl_item(impl_.def_id.expect_local()); + let impl_item_impl_trait_spans: Vec<Span> = impl_item + .generics + .params + .iter() + .filter_map(|p| match p.kind { + GenericParamKind::Type { synthetic: true, .. } => Some(p.span), + _ => None, + }) + .collect(); + let spans = arg_spans(impl_.kind, impl_item.generics); + let span = spans.first().copied(); + + let mut err = tcx.sess.struct_span_err_with_code( + spans, + &format!( + "{} `{}` has {} {kind} parameter{} but its trait \ + declaration has {} {kind} parameter{}", + item_kind, + trait_.name, + impl_count, + pluralize!(impl_count), + trait_count, + pluralize!(trait_count), + kind = kind, + ), + DiagnosticId::Error("E0049".into()), + ); + + let mut suffix = None; + + if let Some(spans) = trait_spans { + let mut spans = spans.iter(); + if let Some(span) = spans.next() { + err.span_label( + *span, + format!( + "expected {} {} parameter{}", + trait_count, + kind, + pluralize!(trait_count), + ), + ); + } + for span in spans { + err.span_label(*span, ""); + } + } else { + suffix = Some(format!(", expected {trait_count}")); + } + + if let Some(span) = span { + err.span_label( + span, + format!( + "found {} {} parameter{}{}", + impl_count, + kind, + pluralize!(impl_count), + suffix.unwrap_or_else(String::new), + ), + ); + } + + for span in impl_trait_spans.iter().chain(impl_item_impl_trait_spans.iter()) { + err.span_label(*span, "`impl Trait` introduces an implicit type parameter"); + } + + let reported = err.emit(); + err_occurred = Some(reported); + } + } + + if let Some(reported) = err_occurred { Err(reported) } else { Ok(()) } +} + +fn compare_number_of_method_arguments<'tcx>( + tcx: TyCtxt<'tcx>, + impl_m: &ty::AssocItem, + impl_m_span: Span, + trait_m: &ty::AssocItem, + trait_item_span: Option<Span>, +) -> Result<(), ErrorGuaranteed> { + let impl_m_fty = tcx.fn_sig(impl_m.def_id); + let trait_m_fty = tcx.fn_sig(trait_m.def_id); + let trait_number_args = trait_m_fty.inputs().skip_binder().len(); + let impl_number_args = impl_m_fty.inputs().skip_binder().len(); + if trait_number_args != impl_number_args { + let trait_span = if let Some(def_id) = trait_m.def_id.as_local() { + match tcx.hir().expect_trait_item(def_id).kind { + TraitItemKind::Fn(ref trait_m_sig, _) => { + let pos = if trait_number_args > 0 { trait_number_args - 1 } else { 0 }; + if let Some(arg) = trait_m_sig.decl.inputs.get(pos) { + Some(if pos == 0 { + arg.span + } else { + arg.span.with_lo(trait_m_sig.decl.inputs[0].span.lo()) + }) + } else { + trait_item_span + } + } + _ => bug!("{:?} is not a method", impl_m), + } + } else { + trait_item_span + }; + let impl_span = match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind { + ImplItemKind::Fn(ref impl_m_sig, _) => { + let pos = if impl_number_args > 0 { impl_number_args - 1 } else { 0 }; + if let Some(arg) = impl_m_sig.decl.inputs.get(pos) { + if pos == 0 { + arg.span + } else { + arg.span.with_lo(impl_m_sig.decl.inputs[0].span.lo()) + } + } else { + impl_m_span + } + } + _ => bug!("{:?} is not a method", impl_m), + }; + let mut err = struct_span_err!( + tcx.sess, + impl_span, + E0050, + "method `{}` has {} but the declaration in trait `{}` has {}", + trait_m.name, + potentially_plural_count(impl_number_args, "parameter"), + tcx.def_path_str(trait_m.def_id), + trait_number_args + ); + if let Some(trait_span) = trait_span { + err.span_label( + trait_span, + format!( + "trait requires {}", + potentially_plural_count(trait_number_args, "parameter") + ), + ); + } else { + err.note_trait_signature(trait_m.name, trait_m.signature(tcx)); + } + err.span_label( + impl_span, + format!( + "expected {}, found {}", + potentially_plural_count(trait_number_args, "parameter"), + impl_number_args + ), + ); + let reported = err.emit(); + return Err(reported); + } + + Ok(()) +} + +fn compare_synthetic_generics<'tcx>( + tcx: TyCtxt<'tcx>, + impl_m: &ty::AssocItem, + trait_m: &ty::AssocItem, +) -> Result<(), ErrorGuaranteed> { + // FIXME(chrisvittal) Clean up this function, list of FIXME items: + // 1. Better messages for the span labels + // 2. Explanation as to what is going on + // If we get here, we already have the same number of generics, so the zip will + // be okay. + let mut error_found = None; + let impl_m_generics = tcx.generics_of(impl_m.def_id); + let trait_m_generics = tcx.generics_of(trait_m.def_id); + let impl_m_type_params = impl_m_generics.params.iter().filter_map(|param| match param.kind { + GenericParamDefKind::Type { synthetic, .. } => Some((param.def_id, synthetic)), + GenericParamDefKind::Lifetime | GenericParamDefKind::Const { .. } => None, + }); + let trait_m_type_params = trait_m_generics.params.iter().filter_map(|param| match param.kind { + GenericParamDefKind::Type { synthetic, .. } => Some((param.def_id, synthetic)), + GenericParamDefKind::Lifetime | GenericParamDefKind::Const { .. } => None, + }); + for ((impl_def_id, impl_synthetic), (trait_def_id, trait_synthetic)) in + iter::zip(impl_m_type_params, trait_m_type_params) + { + if impl_synthetic != trait_synthetic { + let impl_def_id = impl_def_id.expect_local(); + let impl_span = tcx.def_span(impl_def_id); + let trait_span = tcx.def_span(trait_def_id); + let mut err = struct_span_err!( + tcx.sess, + impl_span, + E0643, + "method `{}` has incompatible signature for trait", + trait_m.name + ); + err.span_label(trait_span, "declaration in trait here"); + match (impl_synthetic, trait_synthetic) { + // The case where the impl method uses `impl Trait` but the trait method uses + // explicit generics + (true, false) => { + err.span_label(impl_span, "expected generic parameter, found `impl Trait`"); + (|| { + // try taking the name from the trait impl + // FIXME: this is obviously suboptimal since the name can already be used + // as another generic argument + let new_name = tcx.opt_item_name(trait_def_id)?; + let trait_m = trait_m.def_id.as_local()?; + let trait_m = tcx.hir().expect_trait_item(trait_m); + + let impl_m = impl_m.def_id.as_local()?; + let impl_m = tcx.hir().expect_impl_item(impl_m); + + // in case there are no generics, take the spot between the function name + // and the opening paren of the argument list + let new_generics_span = tcx.def_ident_span(impl_def_id)?.shrink_to_hi(); + // in case there are generics, just replace them + let generics_span = + impl_m.generics.span.substitute_dummy(new_generics_span); + // replace with the generics from the trait + let new_generics = + tcx.sess.source_map().span_to_snippet(trait_m.generics.span).ok()?; + + err.multipart_suggestion( + "try changing the `impl Trait` argument to a generic parameter", + vec![ + // replace `impl Trait` with `T` + (impl_span, new_name.to_string()), + // replace impl method generics with trait method generics + // This isn't quite right, as users might have changed the names + // of the generics, but it works for the common case + (generics_span, new_generics), + ], + Applicability::MaybeIncorrect, + ); + Some(()) + })(); + } + // The case where the trait method uses `impl Trait`, but the impl method uses + // explicit generics. + (false, true) => { + err.span_label(impl_span, "expected `impl Trait`, found generic parameter"); + (|| { + let impl_m = impl_m.def_id.as_local()?; + let impl_m = tcx.hir().expect_impl_item(impl_m); + let input_tys = match impl_m.kind { + hir::ImplItemKind::Fn(ref sig, _) => sig.decl.inputs, + _ => unreachable!(), + }; + struct Visitor(Option<Span>, hir::def_id::LocalDefId); + impl<'v> intravisit::Visitor<'v> for Visitor { + fn visit_ty(&mut self, ty: &'v hir::Ty<'v>) { + intravisit::walk_ty(self, ty); + if let hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) = + ty.kind + && let Res::Def(DefKind::TyParam, def_id) = path.res + && def_id == self.1.to_def_id() + { + self.0 = Some(ty.span); + } + } + } + let mut visitor = Visitor(None, impl_def_id); + for ty in input_tys { + intravisit::Visitor::visit_ty(&mut visitor, ty); + } + let span = visitor.0?; + + let bounds = impl_m.generics.bounds_for_param(impl_def_id).next()?.bounds; + let bounds = bounds.first()?.span().to(bounds.last()?.span()); + let bounds = tcx.sess.source_map().span_to_snippet(bounds).ok()?; + + err.multipart_suggestion( + "try removing the generic parameter and using `impl Trait` instead", + vec![ + // delete generic parameters + (impl_m.generics.span, String::new()), + // replace param usage with `impl Trait` + (span, format!("impl {bounds}")), + ], + Applicability::MaybeIncorrect, + ); + Some(()) + })(); + } + _ => unreachable!(), + } + let reported = err.emit(); + error_found = Some(reported); + } + } + if let Some(reported) = error_found { Err(reported) } else { Ok(()) } +} + +/// Checks that all parameters in the generics of a given assoc item in a trait impl have +/// the same kind as the respective generic parameter in the trait def. +/// +/// For example all 4 errors in the following code are emitted here: +/// ``` +/// trait Foo { +/// fn foo<const N: u8>(); +/// type bar<const N: u8>; +/// fn baz<const N: u32>(); +/// type blah<T>; +/// } +/// +/// impl Foo for () { +/// fn foo<const N: u64>() {} +/// //~^ error +/// type bar<const N: u64> {} +/// //~^ error +/// fn baz<T>() {} +/// //~^ error +/// type blah<const N: i64> = u32; +/// //~^ error +/// } +/// ``` +/// +/// This function does not handle lifetime parameters +fn compare_generic_param_kinds<'tcx>( + tcx: TyCtxt<'tcx>, + impl_item: &ty::AssocItem, + trait_item: &ty::AssocItem, +) -> Result<(), ErrorGuaranteed> { + assert_eq!(impl_item.kind, trait_item.kind); + + let ty_const_params_of = |def_id| { + tcx.generics_of(def_id).params.iter().filter(|param| { + matches!( + param.kind, + GenericParamDefKind::Const { .. } | GenericParamDefKind::Type { .. } + ) + }) + }; + + for (param_impl, param_trait) in + iter::zip(ty_const_params_of(impl_item.def_id), ty_const_params_of(trait_item.def_id)) + { + use GenericParamDefKind::*; + if match (¶m_impl.kind, ¶m_trait.kind) { + (Const { .. }, Const { .. }) + if tcx.type_of(param_impl.def_id) != tcx.type_of(param_trait.def_id) => + { + true + } + (Const { .. }, Type { .. }) | (Type { .. }, Const { .. }) => true, + // this is exhaustive so that anyone adding new generic param kinds knows + // to make sure this error is reported for them. + (Const { .. }, Const { .. }) | (Type { .. }, Type { .. }) => false, + (Lifetime { .. }, _) | (_, Lifetime { .. }) => unreachable!(), + } { + let param_impl_span = tcx.def_span(param_impl.def_id); + let param_trait_span = tcx.def_span(param_trait.def_id); + + let mut err = struct_span_err!( + tcx.sess, + param_impl_span, + E0053, + "{} `{}` has an incompatible generic parameter for trait `{}`", + assoc_item_kind_str(&impl_item), + trait_item.name, + &tcx.def_path_str(tcx.parent(trait_item.def_id)) + ); + + let make_param_message = |prefix: &str, param: &ty::GenericParamDef| match param.kind { + Const { .. } => { + format!("{} const parameter of type `{}`", prefix, tcx.type_of(param.def_id)) + } + Type { .. } => format!("{} type parameter", prefix), + Lifetime { .. } => unreachable!(), + }; + + let trait_header_span = tcx.def_ident_span(tcx.parent(trait_item.def_id)).unwrap(); + err.span_label(trait_header_span, ""); + err.span_label(param_trait_span, make_param_message("expected", param_trait)); + + let impl_header_span = tcx.def_span(tcx.parent(impl_item.def_id)); + err.span_label(impl_header_span, ""); + err.span_label(param_impl_span, make_param_message("found", param_impl)); + + let reported = err.emit(); + return Err(reported); + } + } + + Ok(()) +} + +/// Use `tcx.compare_assoc_const_impl_item_with_trait_item` instead +pub(crate) fn raw_compare_const_impl<'tcx>( + tcx: TyCtxt<'tcx>, + (impl_const_item_def, trait_const_item_def): (LocalDefId, DefId), +) -> Result<(), ErrorGuaranteed> { + let impl_const_item = tcx.associated_item(impl_const_item_def); + let trait_const_item = tcx.associated_item(trait_const_item_def); + let impl_trait_ref = tcx.impl_trait_ref(impl_const_item.container_id(tcx)).unwrap(); + debug!("compare_const_impl(impl_trait_ref={:?})", impl_trait_ref); + + let impl_c_span = tcx.def_span(impl_const_item_def.to_def_id()); + + let infcx = tcx.infer_ctxt().build(); + let param_env = tcx.param_env(impl_const_item_def.to_def_id()); + let ocx = ObligationCtxt::new(&infcx); + + // The below is for the most part highly similar to the procedure + // for methods above. It is simpler in many respects, especially + // because we shouldn't really have to deal with lifetimes or + // predicates. In fact some of this should probably be put into + // shared functions because of DRY violations... + let trait_to_impl_substs = impl_trait_ref.substs; + + // Create a parameter environment that represents the implementation's + // method. + let impl_c_hir_id = tcx.hir().local_def_id_to_hir_id(impl_const_item_def); + + // Compute placeholder form of impl and trait const tys. + let impl_ty = tcx.type_of(impl_const_item_def.to_def_id()); + let trait_ty = tcx.bound_type_of(trait_const_item_def).subst(tcx, trait_to_impl_substs); + let mut cause = ObligationCause::new( + impl_c_span, + impl_c_hir_id, + ObligationCauseCode::CompareImplItemObligation { + impl_item_def_id: impl_const_item_def, + trait_item_def_id: trait_const_item_def, + kind: impl_const_item.kind, + }, + ); + + // There is no "body" here, so just pass dummy id. + let impl_ty = ocx.normalize(cause.clone(), param_env, impl_ty); + + debug!("compare_const_impl: impl_ty={:?}", impl_ty); + + let trait_ty = ocx.normalize(cause.clone(), param_env, trait_ty); + + debug!("compare_const_impl: trait_ty={:?}", trait_ty); + + let err = infcx + .at(&cause, param_env) + .sup(trait_ty, impl_ty) + .map(|ok| ocx.register_infer_ok_obligations(ok)); + + if let Err(terr) = err { + debug!( + "checking associated const for compatibility: impl ty {:?}, trait ty {:?}", + impl_ty, trait_ty + ); + + // Locate the Span containing just the type of the offending impl + match tcx.hir().expect_impl_item(impl_const_item_def).kind { + ImplItemKind::Const(ref ty, _) => cause.span = ty.span, + _ => bug!("{:?} is not a impl const", impl_const_item), + } + + let mut diag = struct_span_err!( + tcx.sess, + cause.span, + E0326, + "implemented const `{}` has an incompatible type for trait", + trait_const_item.name + ); + + let trait_c_span = trait_const_item_def.as_local().map(|trait_c_def_id| { + // Add a label to the Span containing just the type of the const + match tcx.hir().expect_trait_item(trait_c_def_id).kind { + TraitItemKind::Const(ref ty, _) => ty.span, + _ => bug!("{:?} is not a trait const", trait_const_item), + } + }); + + infcx.err_ctxt().note_type_err( + &mut diag, + &cause, + trait_c_span.map(|span| (span, "type in trait".to_owned())), + Some(infer::ValuePairs::Terms(ExpectedFound { + expected: trait_ty.into(), + found: impl_ty.into(), + })), + terr, + false, + false, + ); + return Err(diag.emit()); + }; + + // Check that all obligations are satisfied by the implementation's + // version. + let errors = ocx.select_all_or_error(); + if !errors.is_empty() { + return Err(infcx.err_ctxt().report_fulfillment_errors(&errors, None, false)); + } + + // FIXME return `ErrorReported` if region obligations error? + let outlives_environment = OutlivesEnvironment::new(param_env); + infcx.check_region_obligations_and_report_errors(impl_const_item_def, &outlives_environment); + Ok(()) +} + +pub(crate) fn compare_ty_impl<'tcx>( + tcx: TyCtxt<'tcx>, + impl_ty: &ty::AssocItem, + impl_ty_span: Span, + trait_ty: &ty::AssocItem, + impl_trait_ref: ty::TraitRef<'tcx>, + trait_item_span: Option<Span>, +) { + debug!("compare_impl_type(impl_trait_ref={:?})", impl_trait_ref); + + let _: Result<(), ErrorGuaranteed> = (|| { + compare_number_of_generics(tcx, impl_ty, impl_ty_span, trait_ty, trait_item_span)?; + + compare_generic_param_kinds(tcx, impl_ty, trait_ty)?; + + let sp = tcx.def_span(impl_ty.def_id); + compare_type_predicate_entailment(tcx, impl_ty, sp, trait_ty, impl_trait_ref)?; + + check_type_bounds(tcx, trait_ty, impl_ty, impl_ty_span, impl_trait_ref) + })(); +} + +/// The equivalent of [compare_predicate_entailment], but for associated types +/// instead of associated functions. +fn compare_type_predicate_entailment<'tcx>( + tcx: TyCtxt<'tcx>, + impl_ty: &ty::AssocItem, + impl_ty_span: Span, + trait_ty: &ty::AssocItem, + impl_trait_ref: ty::TraitRef<'tcx>, +) -> Result<(), ErrorGuaranteed> { + let impl_substs = InternalSubsts::identity_for_item(tcx, impl_ty.def_id); + let trait_to_impl_substs = + impl_substs.rebase_onto(tcx, impl_ty.container_id(tcx), impl_trait_ref.substs); + + let impl_ty_generics = tcx.generics_of(impl_ty.def_id); + let trait_ty_generics = tcx.generics_of(trait_ty.def_id); + let impl_ty_predicates = tcx.predicates_of(impl_ty.def_id); + let trait_ty_predicates = tcx.predicates_of(trait_ty.def_id); + + check_region_bounds_on_impl_item( + tcx, + impl_ty, + trait_ty, + &trait_ty_generics, + &impl_ty_generics, + )?; + + let impl_ty_own_bounds = impl_ty_predicates.instantiate_own(tcx, impl_substs); + + if impl_ty_own_bounds.is_empty() { + // Nothing to check. + return Ok(()); + } + + // This `HirId` should be used for the `body_id` field on each + // `ObligationCause` (and the `FnCtxt`). This is what + // `regionck_item` expects. + let impl_ty_hir_id = tcx.hir().local_def_id_to_hir_id(impl_ty.def_id.expect_local()); + debug!("compare_type_predicate_entailment: trait_to_impl_substs={:?}", trait_to_impl_substs); + + // The predicates declared by the impl definition, the trait and the + // associated type in the trait are assumed. + let impl_predicates = tcx.predicates_of(impl_ty_predicates.parent.unwrap()); + let mut hybrid_preds = impl_predicates.instantiate_identity(tcx); + hybrid_preds + .predicates + .extend(trait_ty_predicates.instantiate_own(tcx, trait_to_impl_substs).predicates); + + debug!("compare_type_predicate_entailment: bounds={:?}", hybrid_preds); + + let normalize_cause = traits::ObligationCause::misc(impl_ty_span, impl_ty_hir_id); + let param_env = ty::ParamEnv::new( + tcx.intern_predicates(&hybrid_preds.predicates), + Reveal::UserFacing, + hir::Constness::NotConst, + ); + let param_env = traits::normalize_param_env_or_error(tcx, param_env, normalize_cause); + let infcx = tcx.infer_ctxt().build(); + let ocx = ObligationCtxt::new(&infcx); + + debug!("compare_type_predicate_entailment: caller_bounds={:?}", param_env.caller_bounds()); + + let mut selcx = traits::SelectionContext::new(&infcx); + + assert_eq!(impl_ty_own_bounds.predicates.len(), impl_ty_own_bounds.spans.len()); + for (span, predicate) in std::iter::zip(impl_ty_own_bounds.spans, impl_ty_own_bounds.predicates) + { + let cause = ObligationCause::misc(span, impl_ty_hir_id); + let traits::Normalized { value: predicate, obligations } = + traits::normalize(&mut selcx, param_env, cause, predicate); + + let cause = ObligationCause::new( + span, + impl_ty_hir_id, + ObligationCauseCode::CompareImplItemObligation { + impl_item_def_id: impl_ty.def_id.expect_local(), + trait_item_def_id: trait_ty.def_id, + kind: impl_ty.kind, + }, + ); + ocx.register_obligations(obligations); + ocx.register_obligation(traits::Obligation::new(cause, param_env, predicate)); + } + + // Check that all obligations are satisfied by the implementation's + // version. + let errors = ocx.select_all_or_error(); + if !errors.is_empty() { + let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); + return Err(reported); + } + + // Finally, resolve all regions. This catches wily misuses of + // lifetime parameters. + let outlives_environment = OutlivesEnvironment::new(param_env); + infcx.check_region_obligations_and_report_errors( + impl_ty.def_id.expect_local(), + &outlives_environment, + ); + + Ok(()) +} + +/// Validate that `ProjectionCandidate`s created for this associated type will +/// be valid. +/// +/// Usually given +/// +/// trait X { type Y: Copy } impl X for T { type Y = S; } +/// +/// We are able to normalize `<T as X>::U` to `S`, and so when we check the +/// impl is well-formed we have to prove `S: Copy`. +/// +/// For default associated types the normalization is not possible (the value +/// from the impl could be overridden). We also can't normalize generic +/// associated types (yet) because they contain bound parameters. +#[instrument(level = "debug", skip(tcx))] +pub fn check_type_bounds<'tcx>( + tcx: TyCtxt<'tcx>, + trait_ty: &ty::AssocItem, + impl_ty: &ty::AssocItem, + impl_ty_span: Span, + impl_trait_ref: ty::TraitRef<'tcx>, +) -> Result<(), ErrorGuaranteed> { + // Given + // + // impl<A, B> Foo<u32> for (A, B) { + // type Bar<C> =... + // } + // + // - `impl_trait_ref` would be `<(A, B) as Foo<u32>> + // - `impl_ty_substs` would be `[A, B, ^0.0]` (`^0.0` here is the bound var with db 0 and index 0) + // - `rebased_substs` would be `[(A, B), u32, ^0.0]`, combining the substs from + // the *trait* with the generic associated type parameters (as bound vars). + // + // A note regarding the use of bound vars here: + // Imagine as an example + // ``` + // trait Family { + // type Member<C: Eq>; + // } + // + // impl Family for VecFamily { + // type Member<C: Eq> = i32; + // } + // ``` + // Here, we would generate + // ```notrust + // forall<C> { Normalize(<VecFamily as Family>::Member<C> => i32) } + // ``` + // when we really would like to generate + // ```notrust + // forall<C> { Normalize(<VecFamily as Family>::Member<C> => i32) :- Implemented(C: Eq) } + // ``` + // But, this is probably fine, because although the first clause can be used with types C that + // do not implement Eq, for it to cause some kind of problem, there would have to be a + // VecFamily::Member<X> for some type X where !(X: Eq), that appears in the value of type + // Member<C: Eq> = .... That type would fail a well-formedness check that we ought to be doing + // elsewhere, which would check that any <T as Family>::Member<X> meets the bounds declared in + // the trait (notably, that X: Eq and T: Family). + let defs: &ty::Generics = tcx.generics_of(impl_ty.def_id); + let mut substs = smallvec::SmallVec::with_capacity(defs.count()); + if let Some(def_id) = defs.parent { + let parent_defs = tcx.generics_of(def_id); + InternalSubsts::fill_item(&mut substs, tcx, parent_defs, &mut |param, _| { + tcx.mk_param_from_def(param) + }); + } + let mut bound_vars: smallvec::SmallVec<[ty::BoundVariableKind; 8]> = + smallvec::SmallVec::with_capacity(defs.count()); + InternalSubsts::fill_single(&mut substs, defs, &mut |param, _| match param.kind { + GenericParamDefKind::Type { .. } => { + let kind = ty::BoundTyKind::Param(param.name); + let bound_var = ty::BoundVariableKind::Ty(kind); + bound_vars.push(bound_var); + tcx.mk_ty(ty::Bound( + ty::INNERMOST, + ty::BoundTy { var: ty::BoundVar::from_usize(bound_vars.len() - 1), kind }, + )) + .into() + } + GenericParamDefKind::Lifetime => { + let kind = ty::BoundRegionKind::BrNamed(param.def_id, param.name); + let bound_var = ty::BoundVariableKind::Region(kind); + bound_vars.push(bound_var); + tcx.mk_region(ty::ReLateBound( + ty::INNERMOST, + ty::BoundRegion { var: ty::BoundVar::from_usize(bound_vars.len() - 1), kind }, + )) + .into() + } + GenericParamDefKind::Const { .. } => { + let bound_var = ty::BoundVariableKind::Const; + bound_vars.push(bound_var); + tcx.mk_const(ty::ConstS { + ty: tcx.type_of(param.def_id), + kind: ty::ConstKind::Bound( + ty::INNERMOST, + ty::BoundVar::from_usize(bound_vars.len() - 1), + ), + }) + .into() + } + }); + let bound_vars = tcx.mk_bound_variable_kinds(bound_vars.into_iter()); + let impl_ty_substs = tcx.intern_substs(&substs); + let container_id = impl_ty.container_id(tcx); + + let rebased_substs = impl_ty_substs.rebase_onto(tcx, container_id, impl_trait_ref.substs); + let impl_ty_value = tcx.type_of(impl_ty.def_id); + + let param_env = tcx.param_env(impl_ty.def_id); + + // When checking something like + // + // trait X { type Y: PartialEq<<Self as X>::Y> } + // impl X for T { default type Y = S; } + // + // We will have to prove the bound S: PartialEq<<T as X>::Y>. In this case + // we want <T as X>::Y to normalize to S. This is valid because we are + // checking the default value specifically here. Add this equality to the + // ParamEnv for normalization specifically. + let normalize_param_env = { + let mut predicates = param_env.caller_bounds().iter().collect::<Vec<_>>(); + match impl_ty_value.kind() { + ty::Projection(proj) + if proj.item_def_id == trait_ty.def_id && proj.substs == rebased_substs => + { + // Don't include this predicate if the projected type is + // exactly the same as the projection. This can occur in + // (somewhat dubious) code like this: + // + // impl<T> X for T where T: X { type Y = <T as X>::Y; } + } + _ => predicates.push( + ty::Binder::bind_with_vars( + ty::ProjectionPredicate { + projection_ty: ty::ProjectionTy { + item_def_id: trait_ty.def_id, + substs: rebased_substs, + }, + term: impl_ty_value.into(), + }, + bound_vars, + ) + .to_predicate(tcx), + ), + }; + ty::ParamEnv::new( + tcx.intern_predicates(&predicates), + Reveal::UserFacing, + param_env.constness(), + ) + }; + debug!(?normalize_param_env); + + let impl_ty_hir_id = tcx.hir().local_def_id_to_hir_id(impl_ty.def_id.expect_local()); + let impl_ty_substs = InternalSubsts::identity_for_item(tcx, impl_ty.def_id); + let rebased_substs = impl_ty_substs.rebase_onto(tcx, container_id, impl_trait_ref.substs); + + let infcx = tcx.infer_ctxt().build(); + let ocx = ObligationCtxt::new(&infcx); + + let assumed_wf_types = + ocx.assumed_wf_types(param_env, impl_ty_span, impl_ty.def_id.expect_local()); + + let mut selcx = traits::SelectionContext::new(&infcx); + let normalize_cause = ObligationCause::new( + impl_ty_span, + impl_ty_hir_id, + ObligationCauseCode::CheckAssociatedTypeBounds { + impl_item_def_id: impl_ty.def_id.expect_local(), + trait_item_def_id: trait_ty.def_id, + }, + ); + let mk_cause = |span: Span| { + let code = if span.is_dummy() { + traits::ItemObligation(trait_ty.def_id) + } else { + traits::BindingObligation(trait_ty.def_id, span) + }; + ObligationCause::new(impl_ty_span, impl_ty_hir_id, code) + }; + + let obligations = tcx + .bound_explicit_item_bounds(trait_ty.def_id) + .subst_iter_copied(tcx, rebased_substs) + .map(|(concrete_ty_bound, span)| { + debug!("check_type_bounds: concrete_ty_bound = {:?}", concrete_ty_bound); + traits::Obligation::new(mk_cause(span), param_env, concrete_ty_bound) + }) + .collect(); + debug!("check_type_bounds: item_bounds={:?}", obligations); + + for mut obligation in util::elaborate_obligations(tcx, obligations) { + let traits::Normalized { value: normalized_predicate, obligations } = traits::normalize( + &mut selcx, + normalize_param_env, + normalize_cause.clone(), + obligation.predicate, + ); + debug!("compare_projection_bounds: normalized predicate = {:?}", normalized_predicate); + obligation.predicate = normalized_predicate; + + ocx.register_obligations(obligations); + ocx.register_obligation(obligation); + } + // Check that all obligations are satisfied by the implementation's + // version. + let errors = ocx.select_all_or_error(); + if !errors.is_empty() { + let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); + return Err(reported); + } + + // Finally, resolve all regions. This catches wily misuses of + // lifetime parameters. + let implied_bounds = infcx.implied_bounds_tys(param_env, impl_ty_hir_id, assumed_wf_types); + let outlives_environment = + OutlivesEnvironment::with_bounds(param_env, Some(&infcx), implied_bounds); + + infcx.check_region_obligations_and_report_errors( + impl_ty.def_id.expect_local(), + &outlives_environment, + ); + + let constraints = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types(); + for (key, value) in constraints { + infcx + .err_ctxt() + .report_mismatched_types( + &ObligationCause::misc( + value.hidden_type.span, + tcx.hir().local_def_id_to_hir_id(impl_ty.def_id.expect_local()), + ), + tcx.mk_opaque(key.def_id.to_def_id(), key.substs), + value.hidden_type.ty, + TypeError::Mismatch, + ) + .emit(); + } + + Ok(()) +} + +fn assoc_item_kind_str(impl_item: &ty::AssocItem) -> &'static str { + match impl_item.kind { + ty::AssocKind::Const => "const", + ty::AssocKind::Fn => "method", + ty::AssocKind::Type => "type", + } +} diff --git a/compiler/rustc_typeck/src/check/dropck.rs b/compiler/rustc_hir_analysis/src/check/dropck.rs index 321064ec0..a74016e22 100644 --- a/compiler/rustc_typeck/src/check/dropck.rs +++ b/compiler/rustc_hir_analysis/src/check/dropck.rs @@ -1,4 +1,4 @@ -// FIXME(@lcnr): Move this module out of `rustc_typeck`. +// FIXME(@lcnr): Move this module out of `rustc_hir_analysis`. // // We don't do any drop checking during hir typeck. use crate::hir::def_id::{DefId, LocalDefId}; @@ -144,6 +144,8 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>( let assumptions_in_impl_context = generic_assumptions.instantiate(tcx, &self_to_impl_substs); let assumptions_in_impl_context = assumptions_in_impl_context.predicates; + debug!(?assumptions_in_impl_context, ?dtor_predicates.predicates); + let self_param_env = tcx.param_env(self_type_did); // An earlier version of this code attempted to do this checking @@ -182,13 +184,7 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>( let p = p.kind(); match (predicate.skip_binder(), p.skip_binder()) { (ty::PredicateKind::Trait(a), ty::PredicateKind::Trait(b)) => { - // Since struct predicates cannot have ~const, project the impl predicate - // onto one that ignores the constness. This is equivalent to saying that - // we match a `Trait` bound on the struct with a `Trait` or `~const Trait` - // in the impl. - let non_const_a = - ty::TraitPredicate { constness: ty::BoundConstness::NotConst, ..a }; - relator.relate(predicate.rebind(non_const_a), p.rebind(b)).is_ok() + relator.relate(predicate.rebind(a), p.rebind(b)).is_ok() } (ty::PredicateKind::Projection(a), ty::PredicateKind::Projection(b)) => { relator.relate(predicate.rebind(a), p.rebind(b)).is_ok() @@ -196,7 +192,7 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>( ( ty::PredicateKind::ConstEvaluatable(a), ty::PredicateKind::ConstEvaluatable(b), - ) => tcx.try_unify_abstract_consts(self_param_env.and((a, b))), + ) => relator.relate(predicate.rebind(a), predicate.rebind(b)).is_ok(), ( ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty_a, lt_a)), ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty_b, lt_b)), diff --git a/compiler/rustc_typeck/src/check/intrinsic.rs b/compiler/rustc_hir_analysis/src/check/intrinsic.rs index 3f2a0da8d..609095c9c 100644 --- a/compiler/rustc_typeck/src/check/intrinsic.rs +++ b/compiler/rustc_hir_analysis/src/check/intrinsic.rs @@ -7,10 +7,10 @@ use crate::errors::{ }; use crate::require_same_types; -use rustc_errors::struct_span_err; +use hir::def_id::DefId; +use rustc_errors::{struct_span_err, DiagnosticMessage}; use rustc_hir as hir; use rustc_middle::traits::{ObligationCause, ObligationCauseCode}; -use rustc_middle::ty::subst::Subst; use rustc_middle::ty::{self, TyCtxt}; use rustc_span::symbol::{kw, sym, Symbol}; use rustc_target::spec::abi::Abi; @@ -26,7 +26,7 @@ fn equate_intrinsic_type<'tcx>( ) { let (own_counts, span) = match &it.kind { hir::ForeignItemKind::Fn(.., generics) => { - let own_counts = tcx.generics_of(it.def_id.to_def_id()).own_counts(); + let own_counts = tcx.generics_of(it.owner_id.to_def_id()).own_counts(); (own_counts, generics.span) } _ => { @@ -57,18 +57,25 @@ fn equate_intrinsic_type<'tcx>( { let fty = tcx.mk_fn_ptr(sig); let cause = ObligationCause::new(it.span, it.hir_id(), ObligationCauseCode::IntrinsicType); - require_same_types(tcx, &cause, tcx.mk_fn_ptr(tcx.fn_sig(it.def_id)), fty); + require_same_types(tcx, &cause, tcx.mk_fn_ptr(tcx.fn_sig(it.owner_id)), fty); } } /// Returns the unsafety of the given intrinsic. -pub fn intrinsic_operation_unsafety(intrinsic: Symbol) -> hir::Unsafety { - match intrinsic { +pub fn intrinsic_operation_unsafety(tcx: TyCtxt<'_>, intrinsic_id: DefId) -> hir::Unsafety { + let has_safe_attr = match tcx.has_attr(intrinsic_id, sym::rustc_safe_intrinsic) { + true => hir::Unsafety::Normal, + false => hir::Unsafety::Unsafe, + }; + let is_in_list = match tcx.item_name(intrinsic_id) { // When adding a new intrinsic to this list, // it's usually worth updating that intrinsic's documentation // to note that it's safe to call, since // safe extern fns are otherwise unprecedented. sym::abort + | sym::assert_inhabited + | sym::assert_zero_valid + | sym::assert_uninit_valid | sym::size_of | sym::min_align_of | sym::needs_drop @@ -92,8 +99,7 @@ pub fn intrinsic_operation_unsafety(intrinsic: Symbol) -> hir::Unsafety { | sym::type_id | sym::likely | sym::unlikely - | sym::ptr_guaranteed_eq - | sym::ptr_guaranteed_ne + | sym::ptr_guaranteed_cmp | sym::minnumf32 | sym::minnumf64 | sym::maxnumf32 @@ -102,16 +108,29 @@ pub fn intrinsic_operation_unsafety(intrinsic: Symbol) -> hir::Unsafety { | sym::type_name | sym::forget | sym::black_box - | sym::variant_count => hir::Unsafety::Normal, + | sym::variant_count + | sym::ptr_mask => hir::Unsafety::Normal, _ => hir::Unsafety::Unsafe, + }; + + if has_safe_attr != is_in_list { + tcx.sess.struct_span_err( + tcx.def_span(intrinsic_id), + DiagnosticMessage::Str(format!( + "intrinsic safety mismatch between list of intrinsics within the compiler and core library intrinsics for intrinsic `{}`", + tcx.item_name(intrinsic_id) + ))).emit(); } + + is_in_list } /// Remember to add all intrinsics here, in `compiler/rustc_codegen_llvm/src/intrinsic.rs`, /// and in `library/core/src/intrinsics.rs`. pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) { let param = |n| tcx.mk_ty_param(n, Symbol::intern(&format!("P{}", n))); - let intrinsic_name = tcx.item_name(it.def_id.to_def_id()); + let intrinsic_id = it.owner_id.to_def_id(); + let intrinsic_name = tcx.item_name(intrinsic_id); let name_str = intrinsic_name.as_str(); let bound_vars = tcx.mk_bound_variable_kinds( @@ -158,7 +177,7 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) { }; (n_tps, 0, inputs, output, hir::Unsafety::Unsafe) } else { - let unsafety = intrinsic_operation_unsafety(intrinsic_name); + let unsafety = intrinsic_operation_unsafety(tcx, intrinsic_id); let (n_tps, inputs, output) = match intrinsic_name { sym::abort => (0, Vec::new(), tcx.types.never), sym::unreachable => (0, Vec::new(), tcx.types.never), @@ -200,6 +219,15 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) { ], tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }), ), + sym::ptr_mask => ( + 1, + vec![ + tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }), + tcx.types.usize, + ], + tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }), + ), + sym::copy | sym::copy_nonoverlapping => ( 1, vec![ @@ -289,8 +317,8 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) { (1, vec![param(0), param(0)], tcx.intern_tup(&[param(0), tcx.types.bool])) } - sym::ptr_guaranteed_eq | sym::ptr_guaranteed_ne => { - (1, vec![tcx.mk_imm_ptr(param(0)), tcx.mk_imm_ptr(param(0))], tcx.types.bool) + sym::ptr_guaranteed_cmp => { + (1, vec![tcx.mk_imm_ptr(param(0)), tcx.mk_imm_ptr(param(0))], tcx.types.u8) } sym::const_allocate => { @@ -465,7 +493,11 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) sym::simd_scatter => (3, vec![param(0), param(1), param(2)], tcx.mk_unit()), sym::simd_insert => (2, vec![param(0), tcx.types.u32, param(1)], param(0)), sym::simd_extract => (2, vec![param(0), tcx.types.u32], param(1)), - sym::simd_cast | sym::simd_as => (2, vec![param(0)], param(1)), + sym::simd_cast + | sym::simd_as + | sym::simd_cast_ptr + | sym::simd_expose_addr + | sym::simd_from_exposed_addr => (2, vec![param(0)], param(1)), sym::simd_bitmask => (2, vec![param(0)], param(1)), sym::simd_select | sym::simd_select_bitmask => { (2, vec![param(0), param(1), param(1)], param(1)) diff --git a/compiler/rustc_hir_analysis/src/check/intrinsicck.rs b/compiler/rustc_hir_analysis/src/check/intrinsicck.rs new file mode 100644 index 000000000..17c4d0d48 --- /dev/null +++ b/compiler/rustc_hir_analysis/src/check/intrinsicck.rs @@ -0,0 +1,437 @@ +use rustc_ast::InlineAsmTemplatePiece; +use rustc_data_structures::fx::FxHashSet; +use rustc_hir as hir; +use rustc_middle::ty::{self, Article, FloatTy, IntTy, Ty, TyCtxt, TypeVisitable, UintTy}; +use rustc_session::lint; +use rustc_span::{Symbol, DUMMY_SP}; +use rustc_target::asm::{InlineAsmReg, InlineAsmRegClass, InlineAsmRegOrRegClass, InlineAsmType}; + +pub struct InlineAsmCtxt<'a, 'tcx> { + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + get_operand_ty: Box<dyn Fn(&'tcx hir::Expr<'tcx>) -> Ty<'tcx> + 'a>, +} + +impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> { + pub fn new_global_asm(tcx: TyCtxt<'tcx>) -> Self { + InlineAsmCtxt { + tcx, + param_env: ty::ParamEnv::empty(), + get_operand_ty: Box::new(|e| bug!("asm operand in global asm: {e:?}")), + } + } + + pub fn new_in_fn( + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + get_operand_ty: impl Fn(&'tcx hir::Expr<'tcx>) -> Ty<'tcx> + 'a, + ) -> Self { + InlineAsmCtxt { tcx, param_env, get_operand_ty: Box::new(get_operand_ty) } + } + + // FIXME(compiler-errors): This could use `<$ty as Pointee>::Metadata == ()` + fn is_thin_ptr_ty(&self, ty: Ty<'tcx>) -> bool { + // Type still may have region variables, but `Sized` does not depend + // on those, so just erase them before querying. + if ty.is_sized(self.tcx, self.param_env) { + return true; + } + if let ty::Foreign(..) = ty.kind() { + return true; + } + false + } + + fn check_asm_operand_type( + &self, + idx: usize, + reg: InlineAsmRegOrRegClass, + expr: &'tcx hir::Expr<'tcx>, + template: &[InlineAsmTemplatePiece], + is_input: bool, + tied_input: Option<(&'tcx hir::Expr<'tcx>, Option<InlineAsmType>)>, + target_features: &FxHashSet<Symbol>, + ) -> Option<InlineAsmType> { + let ty = (self.get_operand_ty)(expr); + if ty.has_non_region_infer() { + bug!("inference variable in asm operand ty: {:?} {:?}", expr, ty); + } + let asm_ty_isize = match self.tcx.sess.target.pointer_width { + 16 => InlineAsmType::I16, + 32 => InlineAsmType::I32, + 64 => InlineAsmType::I64, + _ => unreachable!(), + }; + + let asm_ty = match *ty.kind() { + // `!` is allowed for input but not for output (issue #87802) + ty::Never if is_input => return None, + ty::Error(_) => return None, + ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => Some(InlineAsmType::I8), + ty::Int(IntTy::I16) | ty::Uint(UintTy::U16) => Some(InlineAsmType::I16), + ty::Int(IntTy::I32) | ty::Uint(UintTy::U32) => Some(InlineAsmType::I32), + ty::Int(IntTy::I64) | ty::Uint(UintTy::U64) => Some(InlineAsmType::I64), + ty::Int(IntTy::I128) | ty::Uint(UintTy::U128) => Some(InlineAsmType::I128), + ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize) => Some(asm_ty_isize), + ty::Float(FloatTy::F32) => Some(InlineAsmType::F32), + ty::Float(FloatTy::F64) => Some(InlineAsmType::F64), + ty::FnPtr(_) => Some(asm_ty_isize), + ty::RawPtr(ty::TypeAndMut { ty, mutbl: _ }) if self.is_thin_ptr_ty(ty) => { + Some(asm_ty_isize) + } + ty::Adt(adt, substs) if adt.repr().simd() => { + let fields = &adt.non_enum_variant().fields; + let elem_ty = fields[0].ty(self.tcx, substs); + match elem_ty.kind() { + ty::Never | ty::Error(_) => return None, + ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => { + Some(InlineAsmType::VecI8(fields.len() as u64)) + } + ty::Int(IntTy::I16) | ty::Uint(UintTy::U16) => { + Some(InlineAsmType::VecI16(fields.len() as u64)) + } + ty::Int(IntTy::I32) | ty::Uint(UintTy::U32) => { + Some(InlineAsmType::VecI32(fields.len() as u64)) + } + ty::Int(IntTy::I64) | ty::Uint(UintTy::U64) => { + Some(InlineAsmType::VecI64(fields.len() as u64)) + } + ty::Int(IntTy::I128) | ty::Uint(UintTy::U128) => { + Some(InlineAsmType::VecI128(fields.len() as u64)) + } + ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize) => { + Some(match self.tcx.sess.target.pointer_width { + 16 => InlineAsmType::VecI16(fields.len() as u64), + 32 => InlineAsmType::VecI32(fields.len() as u64), + 64 => InlineAsmType::VecI64(fields.len() as u64), + _ => unreachable!(), + }) + } + ty::Float(FloatTy::F32) => Some(InlineAsmType::VecF32(fields.len() as u64)), + ty::Float(FloatTy::F64) => Some(InlineAsmType::VecF64(fields.len() as u64)), + _ => None, + } + } + ty::Infer(_) => unreachable!(), + _ => None, + }; + let Some(asm_ty) = asm_ty else { + let msg = &format!("cannot use value of type `{ty}` for inline assembly"); + let mut err = self.tcx.sess.struct_span_err(expr.span, msg); + err.note( + "only integers, floats, SIMD vectors, pointers and function pointers \ + can be used as arguments for inline assembly", + ); + err.emit(); + return None; + }; + + // Check that the type implements Copy. The only case where this can + // possibly fail is for SIMD types which don't #[derive(Copy)]. + if !ty.is_copy_modulo_regions(self.tcx, self.param_env) { + let msg = "arguments for inline assembly must be copyable"; + let mut err = self.tcx.sess.struct_span_err(expr.span, msg); + err.note(&format!("`{ty}` does not implement the Copy trait")); + err.emit(); + } + + // Ideally we wouldn't need to do this, but LLVM's register allocator + // really doesn't like it when tied operands have different types. + // + // This is purely an LLVM limitation, but we have to live with it since + // there is no way to hide this with implicit conversions. + // + // For the purposes of this check we only look at the `InlineAsmType`, + // which means that pointers and integers are treated as identical (modulo + // size). + if let Some((in_expr, Some(in_asm_ty))) = tied_input { + if in_asm_ty != asm_ty { + let msg = "incompatible types for asm inout argument"; + let mut err = self.tcx.sess.struct_span_err(vec![in_expr.span, expr.span], msg); + + let in_expr_ty = (self.get_operand_ty)(in_expr); + err.span_label(in_expr.span, &format!("type `{in_expr_ty}`")); + err.span_label(expr.span, &format!("type `{ty}`")); + err.note( + "asm inout arguments must have the same type, \ + unless they are both pointers or integers of the same size", + ); + err.emit(); + } + + // All of the later checks have already been done on the input, so + // let's not emit errors and warnings twice. + return Some(asm_ty); + } + + // Check the type against the list of types supported by the selected + // register class. + let asm_arch = self.tcx.sess.asm_arch.unwrap(); + let reg_class = reg.reg_class(); + let supported_tys = reg_class.supported_types(asm_arch); + let Some((_, feature)) = supported_tys.iter().find(|&&(t, _)| t == asm_ty) else { + let msg = &format!("type `{ty}` cannot be used with this register class"); + let mut err = self.tcx.sess.struct_span_err(expr.span, msg); + let supported_tys: Vec<_> = + supported_tys.iter().map(|(t, _)| t.to_string()).collect(); + err.note(&format!( + "register class `{}` supports these types: {}", + reg_class.name(), + supported_tys.join(", "), + )); + if let Some(suggest) = reg_class.suggest_class(asm_arch, asm_ty) { + err.help(&format!( + "consider using the `{}` register class instead", + suggest.name() + )); + } + err.emit(); + return Some(asm_ty); + }; + + // Check whether the selected type requires a target feature. Note that + // this is different from the feature check we did earlier. While the + // previous check checked that this register class is usable at all + // with the currently enabled features, some types may only be usable + // with a register class when a certain feature is enabled. We check + // this here since it depends on the results of typeck. + // + // Also note that this check isn't run when the operand type is never + // (!). In that case we still need the earlier check to verify that the + // register class is usable at all. + if let Some(feature) = feature { + if !target_features.contains(&feature) { + let msg = &format!("`{}` target feature is not enabled", feature); + let mut err = self.tcx.sess.struct_span_err(expr.span, msg); + err.note(&format!( + "this is required to use type `{}` with register class `{}`", + ty, + reg_class.name(), + )); + err.emit(); + return Some(asm_ty); + } + } + + // Check whether a modifier is suggested for using this type. + if let Some((suggested_modifier, suggested_result)) = + reg_class.suggest_modifier(asm_arch, asm_ty) + { + // Search for any use of this operand without a modifier and emit + // the suggestion for them. + let mut spans = vec![]; + for piece in template { + if let &InlineAsmTemplatePiece::Placeholder { operand_idx, modifier, span } = piece + { + if operand_idx == idx && modifier.is_none() { + spans.push(span); + } + } + } + if !spans.is_empty() { + let (default_modifier, default_result) = + reg_class.default_modifier(asm_arch).unwrap(); + self.tcx.struct_span_lint_hir( + lint::builtin::ASM_SUB_REGISTER, + expr.hir_id, + spans, + "formatting may not be suitable for sub-register argument", + |lint| { + lint.span_label(expr.span, "for this argument"); + lint.help(&format!( + "use `{{{idx}:{suggested_modifier}}}` to have the register formatted as `{suggested_result}`", + )); + lint.help(&format!( + "or use `{{{idx}:{default_modifier}}}` to keep the default formatting of `{default_result}`", + )); + lint + }, + ); + } + } + + Some(asm_ty) + } + + pub fn check_asm(&self, asm: &hir::InlineAsm<'tcx>, enclosing_id: hir::HirId) { + let hir = self.tcx.hir(); + let enclosing_def_id = hir.local_def_id(enclosing_id).to_def_id(); + let target_features = self.tcx.asm_target_features(enclosing_def_id); + let Some(asm_arch) = self.tcx.sess.asm_arch else { + self.tcx.sess.delay_span_bug(DUMMY_SP, "target architecture does not support asm"); + return; + }; + for (idx, (op, op_sp)) in asm.operands.iter().enumerate() { + // Validate register classes against currently enabled target + // features. We check that at least one type is available for + // the enabled features. + // + // We ignore target feature requirements for clobbers: if the + // feature is disabled then the compiler doesn't care what we + // do with the registers. + // + // Note that this is only possible for explicit register + // operands, which cannot be used in the asm string. + if let Some(reg) = op.reg() { + // Some explicit registers cannot be used depending on the + // target. Reject those here. + if let InlineAsmRegOrRegClass::Reg(reg) = reg { + if let InlineAsmReg::Err = reg { + // `validate` will panic on `Err`, as an error must + // already have been reported. + continue; + } + if let Err(msg) = reg.validate( + asm_arch, + self.tcx.sess.relocation_model(), + &target_features, + &self.tcx.sess.target, + op.is_clobber(), + ) { + let msg = format!("cannot use register `{}`: {}", reg.name(), msg); + self.tcx.sess.struct_span_err(*op_sp, &msg).emit(); + continue; + } + } + + if !op.is_clobber() { + let mut missing_required_features = vec![]; + let reg_class = reg.reg_class(); + if let InlineAsmRegClass::Err = reg_class { + continue; + } + for &(_, feature) in reg_class.supported_types(asm_arch) { + match feature { + Some(feature) => { + if target_features.contains(&feature) { + missing_required_features.clear(); + break; + } else { + missing_required_features.push(feature); + } + } + None => { + missing_required_features.clear(); + break; + } + } + } + + // We are sorting primitive strs here and can use unstable sort here + missing_required_features.sort_unstable(); + missing_required_features.dedup(); + match &missing_required_features[..] { + [] => {} + [feature] => { + let msg = format!( + "register class `{}` requires the `{}` target feature", + reg_class.name(), + feature + ); + self.tcx.sess.struct_span_err(*op_sp, &msg).emit(); + // register isn't enabled, don't do more checks + continue; + } + features => { + let msg = format!( + "register class `{}` requires at least one of the following target features: {}", + reg_class.name(), + features + .iter() + .map(|f| f.as_str()) + .intersperse(", ") + .collect::<String>(), + ); + self.tcx.sess.struct_span_err(*op_sp, &msg).emit(); + // register isn't enabled, don't do more checks + continue; + } + } + } + } + + match *op { + hir::InlineAsmOperand::In { reg, ref expr } => { + self.check_asm_operand_type( + idx, + reg, + expr, + asm.template, + true, + None, + &target_features, + ); + } + hir::InlineAsmOperand::Out { reg, late: _, ref expr } => { + if let Some(expr) = expr { + self.check_asm_operand_type( + idx, + reg, + expr, + asm.template, + false, + None, + &target_features, + ); + } + } + hir::InlineAsmOperand::InOut { reg, late: _, ref expr } => { + self.check_asm_operand_type( + idx, + reg, + expr, + asm.template, + false, + None, + &target_features, + ); + } + hir::InlineAsmOperand::SplitInOut { reg, late: _, ref in_expr, ref out_expr } => { + let in_ty = self.check_asm_operand_type( + idx, + reg, + in_expr, + asm.template, + true, + None, + &target_features, + ); + if let Some(out_expr) = out_expr { + self.check_asm_operand_type( + idx, + reg, + out_expr, + asm.template, + false, + Some((in_expr, in_ty)), + &target_features, + ); + } + } + // No special checking is needed for these: + // - Typeck has checked that Const operands are integers. + // - AST lowering guarantees that SymStatic points to a static. + hir::InlineAsmOperand::Const { .. } | hir::InlineAsmOperand::SymStatic { .. } => {} + // Check that sym actually points to a function. Later passes + // depend on this. + hir::InlineAsmOperand::SymFn { anon_const } => { + let ty = self.tcx.typeck_body(anon_const.body).node_type(anon_const.hir_id); + match ty.kind() { + ty::Never | ty::Error(_) => {} + ty::FnDef(..) => {} + _ => { + let mut err = + self.tcx.sess.struct_span_err(*op_sp, "invalid `sym` operand"); + err.span_label( + self.tcx.hir().span(anon_const.body.hir_id), + &format!("is {} `{}`", ty.kind().article(), ty), + ); + err.help("`sym` operands must refer to either a function or a static"); + err.emit(); + } + }; + } + } + } + } +} diff --git a/compiler/rustc_hir_analysis/src/check/mod.rs b/compiler/rustc_hir_analysis/src/check/mod.rs new file mode 100644 index 000000000..2e7b10257 --- /dev/null +++ b/compiler/rustc_hir_analysis/src/check/mod.rs @@ -0,0 +1,515 @@ +/*! + +# typeck: check phase + +Within the check phase of type check, we check each item one at a time +(bodies of function expressions are checked as part of the containing +function). Inference is used to supply types wherever they are unknown. + +By far the most complex case is checking the body of a function. This +can be broken down into several distinct phases: + +- gather: creates type variables to represent the type of each local + variable and pattern binding. + +- main: the main pass does the lion's share of the work: it + determines the types of all expressions, resolves + methods, checks for most invalid conditions, and so forth. In + some cases, where a type is unknown, it may create a type or region + variable and use that as the type of an expression. + + In the process of checking, various constraints will be placed on + these type variables through the subtyping relationships requested + through the `demand` module. The `infer` module is in charge + of resolving those constraints. + +- regionck: after main is complete, the regionck pass goes over all + types looking for regions and making sure that they did not escape + into places where they are not in scope. This may also influence the + final assignments of the various region variables if there is some + flexibility. + +- writeback: writes the final types within a function body, replacing + type variables with their final inferred types. These final types + are written into the `tcx.node_types` table, which should *never* contain + any reference to a type variable. + +## Intermediate types + +While type checking a function, the intermediate types for the +expressions, blocks, and so forth contained within the function are +stored in `fcx.node_types` and `fcx.node_substs`. These types +may contain unresolved type variables. After type checking is +complete, the functions in the writeback module are used to take the +types from this table, resolve them, and then write them into their +permanent home in the type context `tcx`. + +This means that during inferencing you should use `fcx.write_ty()` +and `fcx.expr_ty()` / `fcx.node_ty()` to write/obtain the types of +nodes within the function. + +The types of top-level items, which never contain unbound type +variables, are stored directly into the `tcx` typeck_results. + +N.B., a type variable is not the same thing as a type parameter. A +type variable is an instance of a type parameter. That is, +given a generic function `fn foo<T>(t: T)`, while checking the +function `foo`, the type `ty_param(0)` refers to the type `T`, which +is treated in abstract. However, when `foo()` is called, `T` will be +substituted for a fresh type variable `N`. This variable will +eventually be resolved to some concrete type (which might itself be +a type parameter). + +*/ + +mod check; +mod compare_method; +pub mod dropck; +pub mod intrinsic; +pub mod intrinsicck; +mod region; +pub mod wfcheck; + +pub use check::check_abi; + +use check::check_mod_item_types; +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_errors::{pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder}; +use rustc_hir as hir; +use rustc_hir::def_id::{DefId, LocalDefId}; +use rustc_hir::intravisit::Visitor; +use rustc_index::bit_set::BitSet; +use rustc_middle::ty::query::Providers; +use rustc_middle::ty::{self, Ty, TyCtxt}; +use rustc_middle::ty::{InternalSubsts, SubstsRef}; +use rustc_session::parse::feature_err; +use rustc_span::source_map::DUMMY_SP; +use rustc_span::symbol::{kw, Ident}; +use rustc_span::{self, BytePos, Span, Symbol}; +use rustc_target::abi::VariantIdx; +use rustc_target::spec::abi::Abi; +use rustc_trait_selection::traits::error_reporting::suggestions::ReturnsVisitor; +use std::num::NonZeroU32; + +use crate::require_c_abi_if_c_variadic; +use crate::util::common::indenter; + +use self::compare_method::collect_trait_impl_trait_tys; +use self::region::region_scope_tree; + +pub fn provide(providers: &mut Providers) { + wfcheck::provide(providers); + *providers = Providers { + adt_destructor, + check_mod_item_types, + region_scope_tree, + collect_trait_impl_trait_tys, + compare_assoc_const_impl_item_with_trait_item: compare_method::raw_compare_const_impl, + ..*providers + }; +} + +fn adt_destructor(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::Destructor> { + tcx.calculate_dtor(def_id, dropck::check_drop_impl) +} + +/// Given a `DefId` for an opaque type in return position, find its parent item's return +/// expressions. +fn get_owner_return_paths<'tcx>( + tcx: TyCtxt<'tcx>, + def_id: LocalDefId, +) -> Option<(LocalDefId, ReturnsVisitor<'tcx>)> { + let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); + let parent_id = tcx.hir().get_parent_item(hir_id).def_id; + tcx.hir().find_by_def_id(parent_id).and_then(|node| node.body_id()).map(|body_id| { + let body = tcx.hir().body(body_id); + let mut visitor = ReturnsVisitor::default(); + visitor.visit_body(body); + (parent_id, visitor) + }) +} + +/// Forbid defining intrinsics in Rust code, +/// as they must always be defined by the compiler. +// FIXME: Move this to a more appropriate place. +pub fn fn_maybe_err(tcx: TyCtxt<'_>, sp: Span, abi: Abi) { + if let Abi::RustIntrinsic | Abi::PlatformIntrinsic = abi { + tcx.sess.span_err(sp, "intrinsic must be in `extern \"rust-intrinsic\" { ... }` block"); + } +} + +fn maybe_check_static_with_link_section(tcx: TyCtxt<'_>, id: LocalDefId) { + // Only restricted on wasm target for now + if !tcx.sess.target.is_like_wasm { + return; + } + + // If `#[link_section]` is missing, then nothing to verify + let attrs = tcx.codegen_fn_attrs(id); + if attrs.link_section.is_none() { + return; + } + + // For the wasm32 target statics with `#[link_section]` are placed into custom + // sections of the final output file, but this isn't link custom sections of + // other executable formats. Namely we can only embed a list of bytes, + // nothing with provenance (pointers to anything else). If any provenance + // show up, reject it here. + // `#[link_section]` may contain arbitrary, or even undefined bytes, but it is + // the consumer's responsibility to ensure all bytes that have been read + // have defined values. + if let Ok(alloc) = tcx.eval_static_initializer(id.to_def_id()) + && alloc.inner().provenance().len() != 0 + { + let msg = "statics with a custom `#[link_section]` must be a \ + simple list of bytes on the wasm target with no \ + extra levels of indirection such as references"; + tcx.sess.span_err(tcx.def_span(id), msg); + } +} + +fn report_forbidden_specialization( + tcx: TyCtxt<'_>, + impl_item: &hir::ImplItemRef, + parent_impl: DefId, +) { + let mut err = struct_span_err!( + tcx.sess, + impl_item.span, + E0520, + "`{}` specializes an item from a parent `impl`, but \ + that item is not marked `default`", + impl_item.ident + ); + err.span_label(impl_item.span, format!("cannot specialize default item `{}`", impl_item.ident)); + + match tcx.span_of_impl(parent_impl) { + Ok(span) => { + err.span_label(span, "parent `impl` is here"); + err.note(&format!( + "to specialize, `{}` in the parent `impl` must be marked `default`", + impl_item.ident + )); + } + Err(cname) => { + err.note(&format!("parent implementation is in crate `{cname}`")); + } + } + + err.emit(); +} + +fn missing_items_err( + tcx: TyCtxt<'_>, + impl_span: Span, + missing_items: &[&ty::AssocItem], + full_impl_span: Span, +) { + let missing_items_msg = missing_items + .iter() + .map(|trait_item| trait_item.name.to_string()) + .collect::<Vec<_>>() + .join("`, `"); + + let mut err = struct_span_err!( + tcx.sess, + impl_span, + E0046, + "not all trait items implemented, missing: `{missing_items_msg}`", + ); + err.span_label(impl_span, format!("missing `{missing_items_msg}` in implementation")); + + // `Span` before impl block closing brace. + let hi = full_impl_span.hi() - BytePos(1); + // Point at the place right before the closing brace of the relevant `impl` to suggest + // adding the associated item at the end of its body. + let sugg_sp = full_impl_span.with_lo(hi).with_hi(hi); + // Obtain the level of indentation ending in `sugg_sp`. + let padding = + tcx.sess.source_map().indentation_before(sugg_sp).unwrap_or_else(|| String::new()); + + for trait_item in missing_items { + let snippet = suggestion_signature(trait_item, tcx); + let code = format!("{}{}\n{}", padding, snippet, padding); + let msg = format!("implement the missing item: `{snippet}`"); + let appl = Applicability::HasPlaceholders; + if let Some(span) = tcx.hir().span_if_local(trait_item.def_id) { + err.span_label(span, format!("`{}` from trait", trait_item.name)); + err.tool_only_span_suggestion(sugg_sp, &msg, code, appl); + } else { + err.span_suggestion_hidden(sugg_sp, &msg, code, appl); + } + } + err.emit(); +} + +fn missing_items_must_implement_one_of_err( + tcx: TyCtxt<'_>, + impl_span: Span, + missing_items: &[Ident], + annotation_span: Option<Span>, +) { + let missing_items_msg = + missing_items.iter().map(Ident::to_string).collect::<Vec<_>>().join("`, `"); + + let mut err = struct_span_err!( + tcx.sess, + impl_span, + E0046, + "not all trait items implemented, missing one of: `{missing_items_msg}`", + ); + err.span_label(impl_span, format!("missing one of `{missing_items_msg}` in implementation")); + + if let Some(annotation_span) = annotation_span { + err.span_note(annotation_span, "required because of this annotation"); + } + + err.emit(); +} + +fn default_body_is_unstable( + tcx: TyCtxt<'_>, + impl_span: Span, + item_did: DefId, + feature: Symbol, + reason: Option<Symbol>, + issue: Option<NonZeroU32>, +) { + let missing_item_name = &tcx.associated_item(item_did).name; + let use_of_unstable_library_feature_note = match reason { + Some(r) => format!("use of unstable library feature '{feature}': {r}"), + None => format!("use of unstable library feature '{feature}'"), + }; + + let mut err = struct_span_err!( + tcx.sess, + impl_span, + E0046, + "not all trait items implemented, missing: `{missing_item_name}`", + ); + err.note(format!("default implementation of `{missing_item_name}` is unstable")); + err.note(use_of_unstable_library_feature_note); + rustc_session::parse::add_feature_diagnostics_for_issue( + &mut err, + &tcx.sess.parse_sess, + feature, + rustc_feature::GateIssue::Library(issue), + ); + err.emit(); +} + +/// Re-sugar `ty::GenericPredicates` in a way suitable to be used in structured suggestions. +fn bounds_from_generic_predicates<'tcx>( + tcx: TyCtxt<'tcx>, + predicates: ty::GenericPredicates<'tcx>, +) -> (String, String) { + let mut types: FxHashMap<Ty<'tcx>, Vec<DefId>> = FxHashMap::default(); + let mut projections = vec![]; + for (predicate, _) in predicates.predicates { + debug!("predicate {:?}", predicate); + let bound_predicate = predicate.kind(); + match bound_predicate.skip_binder() { + ty::PredicateKind::Trait(trait_predicate) => { + let entry = types.entry(trait_predicate.self_ty()).or_default(); + let def_id = trait_predicate.def_id(); + if Some(def_id) != tcx.lang_items().sized_trait() { + // Type params are `Sized` by default, do not add that restriction to the list + // if it is a positive requirement. + entry.push(trait_predicate.def_id()); + } + } + ty::PredicateKind::Projection(projection_pred) => { + projections.push(bound_predicate.rebind(projection_pred)); + } + _ => {} + } + } + let generics = if types.is_empty() { + "".to_string() + } else { + format!( + "<{}>", + types + .keys() + .filter_map(|t| match t.kind() { + ty::Param(_) => Some(t.to_string()), + // Avoid suggesting the following: + // fn foo<T, <T as Trait>::Bar>(_: T) where T: Trait, <T as Trait>::Bar: Other {} + _ => None, + }) + .collect::<Vec<_>>() + .join(", ") + ) + }; + let mut where_clauses = vec![]; + for (ty, bounds) in types { + where_clauses + .extend(bounds.into_iter().map(|bound| format!("{}: {}", ty, tcx.def_path_str(bound)))); + } + for projection in &projections { + let p = projection.skip_binder(); + // FIXME: this is not currently supported syntax, we should be looking at the `types` and + // insert the associated types where they correspond, but for now let's be "lazy" and + // propose this instead of the following valid resugaring: + // `T: Trait, Trait::Assoc = K` → `T: Trait<Assoc = K>` + where_clauses.push(format!( + "{} = {}", + tcx.def_path_str(p.projection_ty.item_def_id), + p.term, + )); + } + let where_clauses = if where_clauses.is_empty() { + String::new() + } else { + format!(" where {}", where_clauses.join(", ")) + }; + (generics, where_clauses) +} + +/// Return placeholder code for the given function. +fn fn_sig_suggestion<'tcx>( + tcx: TyCtxt<'tcx>, + sig: ty::FnSig<'tcx>, + ident: Ident, + predicates: ty::GenericPredicates<'tcx>, + assoc: &ty::AssocItem, +) -> String { + let args = sig + .inputs() + .iter() + .enumerate() + .map(|(i, ty)| { + Some(match ty.kind() { + ty::Param(_) if assoc.fn_has_self_parameter && i == 0 => "self".to_string(), + ty::Ref(reg, ref_ty, mutability) if i == 0 => { + let reg = format!("{reg} "); + let reg = match ®[..] { + "'_ " | " " => "", + reg => reg, + }; + if assoc.fn_has_self_parameter { + match ref_ty.kind() { + ty::Param(param) if param.name == kw::SelfUpper => { + format!("&{}{}self", reg, mutability.prefix_str()) + } + + _ => format!("self: {ty}"), + } + } else { + format!("_: {ty}") + } + } + _ => { + if assoc.fn_has_self_parameter && i == 0 { + format!("self: {ty}") + } else { + format!("_: {ty}") + } + } + }) + }) + .chain(std::iter::once(if sig.c_variadic { Some("...".to_string()) } else { None })) + .flatten() + .collect::<Vec<String>>() + .join(", "); + let output = sig.output(); + let output = if !output.is_unit() { format!(" -> {output}") } else { String::new() }; + + let unsafety = sig.unsafety.prefix_str(); + let (generics, where_clauses) = bounds_from_generic_predicates(tcx, predicates); + + // FIXME: this is not entirely correct, as the lifetimes from borrowed params will + // not be present in the `fn` definition, not will we account for renamed + // lifetimes between the `impl` and the `trait`, but this should be good enough to + // fill in a significant portion of the missing code, and other subsequent + // suggestions can help the user fix the code. + format!("{unsafety}fn {ident}{generics}({args}){output}{where_clauses} {{ todo!() }}") +} + +pub fn ty_kind_suggestion(ty: Ty<'_>) -> Option<&'static str> { + Some(match ty.kind() { + ty::Bool => "true", + ty::Char => "'a'", + ty::Int(_) | ty::Uint(_) => "42", + ty::Float(_) => "3.14159", + ty::Error(_) | ty::Never => return None, + _ => "value", + }) +} + +/// Return placeholder code for the given associated item. +/// Similar to `ty::AssocItem::suggestion`, but appropriate for use as the code snippet of a +/// structured suggestion. +fn suggestion_signature(assoc: &ty::AssocItem, tcx: TyCtxt<'_>) -> String { + match assoc.kind { + ty::AssocKind::Fn => { + // We skip the binder here because the binder would deanonymize all + // late-bound regions, and we don't want method signatures to show up + // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound + // regions just fine, showing `fn(&MyType)`. + fn_sig_suggestion( + tcx, + tcx.fn_sig(assoc.def_id).skip_binder(), + assoc.ident(tcx), + tcx.predicates_of(assoc.def_id), + assoc, + ) + } + ty::AssocKind::Type => format!("type {} = Type;", assoc.name), + ty::AssocKind::Const => { + let ty = tcx.type_of(assoc.def_id); + let val = ty_kind_suggestion(ty).unwrap_or("value"); + format!("const {}: {} = {};", assoc.name, ty, val) + } + } +} + +/// Emit an error when encountering two or more variants in a transparent enum. +fn bad_variant_count<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>, sp: Span, did: DefId) { + let variant_spans: Vec<_> = adt + .variants() + .iter() + .map(|variant| tcx.hir().span_if_local(variant.def_id).unwrap()) + .collect(); + let msg = format!("needs exactly one variant, but has {}", adt.variants().len(),); + let mut err = struct_span_err!(tcx.sess, sp, E0731, "transparent enum {msg}"); + err.span_label(sp, &msg); + if let [start @ .., end] = &*variant_spans { + for variant_span in start { + err.span_label(*variant_span, ""); + } + err.span_label(*end, &format!("too many variants in `{}`", tcx.def_path_str(did))); + } + err.emit(); +} + +/// Emit an error when encountering two or more non-zero-sized fields in a transparent +/// enum. +fn bad_non_zero_sized_fields<'tcx>( + tcx: TyCtxt<'tcx>, + adt: ty::AdtDef<'tcx>, + field_count: usize, + field_spans: impl Iterator<Item = Span>, + sp: Span, +) { + let msg = format!("needs at most one non-zero-sized field, but has {field_count}"); + let mut err = struct_span_err!( + tcx.sess, + sp, + E0690, + "{}transparent {} {}", + if adt.is_enum() { "the variant of a " } else { "" }, + adt.descr(), + msg, + ); + err.span_label(sp, &msg); + for sp in field_spans { + err.span_label(sp, "this field is non-zero-sized"); + } + err.emit(); +} + +// FIXME: Consider moving this method to a more fitting place. +pub fn potentially_plural_count(count: usize, word: &str) -> String { + format!("{} {}{}", count, word, pluralize!(count)) +} diff --git a/compiler/rustc_typeck/src/check/region.rs b/compiler/rustc_hir_analysis/src/check/region.rs index 0081e9049..ff32329e4 100644 --- a/compiler/rustc_typeck/src/check/region.rs +++ b/compiler/rustc_hir_analysis/src/check/region.rs @@ -126,6 +126,29 @@ fn resolve_block<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, blk: &'tcx h for (i, statement) in blk.stmts.iter().enumerate() { match statement.kind { + hir::StmtKind::Local(hir::Local { els: Some(els), .. }) => { + // Let-else has a special lexical structure for variables. + // First we take a checkpoint of the current scope context here. + let mut prev_cx = visitor.cx; + + visitor.enter_scope(Scope { + id: blk.hir_id.local_id, + data: ScopeData::Remainder(FirstStatementIndex::new(i)), + }); + visitor.cx.var_parent = visitor.cx.parent; + visitor.visit_stmt(statement); + // We need to back out temporarily to the last enclosing scope + // for the `else` block, so that even the temporaries receiving + // extended lifetime will be dropped inside this block. + // We are visiting the `else` block in this order so that + // the sequence of visits agree with the order in the default + // `hir::intravisit` visitor. + mem::swap(&mut prev_cx, &mut visitor.cx); + visitor.terminating_scopes.insert(els.hir_id.local_id); + visitor.visit_block(els); + // From now on, we continue normally. + visitor.cx = prev_cx; + } hir::StmtKind::Local(..) | hir::StmtKind::Item(..) => { // Each declaration introduces a subscope for bindings // introduced by the declaration; this subscope covers a @@ -138,10 +161,10 @@ fn resolve_block<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, blk: &'tcx h data: ScopeData::Remainder(FirstStatementIndex::new(i)), }); visitor.cx.var_parent = visitor.cx.parent; + visitor.visit_stmt(statement) } - hir::StmtKind::Expr(..) | hir::StmtKind::Semi(..) => {} + hir::StmtKind::Expr(..) | hir::StmtKind::Semi(..) => visitor.visit_stmt(statement), } - visitor.visit_stmt(statement) } walk_list!(visitor, visit_expr, &blk.expr); } @@ -229,9 +252,13 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h ) => { // For shortcircuiting operators, mark the RHS as a terminating // scope since it only executes conditionally. - terminating(r.hir_id.local_id); - } + // `Let` expressions (in a let-chain) shouldn't be terminating, as their temporaries + // should live beyond the immediate expression + if !matches!(r.kind, hir::ExprKind::Let(_)) { + terminating(r.hir_id.local_id); + } + } hir::ExprKind::If(_, ref then, Some(ref otherwise)) => { terminating(then.hir_id.local_id); terminating(otherwise.hir_id.local_id); @@ -460,7 +487,6 @@ fn resolve_local<'tcx>( visitor: &mut RegionResolutionVisitor<'tcx>, pat: Option<&'tcx hir::Pat<'tcx>>, init: Option<&'tcx hir::Expr<'tcx>>, - els: Option<&'tcx hir::Block<'tcx>>, ) { debug!("resolve_local(pat={:?}, init={:?})", pat, init); @@ -547,9 +573,6 @@ fn resolve_local<'tcx>( if let Some(pat) = pat { visitor.visit_pat(pat); } - if let Some(els) = els { - visitor.visit_block(els); - } /// Returns `true` if `pat` match the `P&` non-terminal. /// @@ -587,8 +610,7 @@ fn resolve_local<'tcx>( // & expression, and its lifetime would be extended to the end of the block (due // to a different rule, not the below code). match pat.kind { - PatKind::Binding(hir::BindingAnnotation::Ref, ..) - | PatKind::Binding(hir::BindingAnnotation::RefMut, ..) => true, + PatKind::Binding(hir::BindingAnnotation(hir::ByRef::Yes, _), ..) => true, PatKind::Struct(_, ref field_pats, _) => { field_pats.iter().any(|fp| is_binding_pat(&fp.pat)) @@ -607,10 +629,7 @@ fn resolve_local<'tcx>( PatKind::Box(ref subpat) => is_binding_pat(&subpat), PatKind::Ref(_, _) - | PatKind::Binding( - hir::BindingAnnotation::Unannotated | hir::BindingAnnotation::Mutable, - .., - ) + | PatKind::Binding(hir::BindingAnnotation(hir::ByRef::No, _), ..) | PatKind::Wild | PatKind::Path(_) | PatKind::Lit(_) @@ -770,7 +789,7 @@ impl<'tcx> Visitor<'tcx> for RegionResolutionVisitor<'tcx> { // (i.e., `'static`), which means that after `g` returns, it drops, // and all the associated destruction scope rules apply. self.cx.var_parent = None; - resolve_local(self, None, Some(&body.value), None); + resolve_local(self, None, Some(&body.value)); } if body.generator_kind.is_some() { @@ -797,7 +816,7 @@ impl<'tcx> Visitor<'tcx> for RegionResolutionVisitor<'tcx> { resolve_expr(self, ex); } fn visit_local(&mut self, l: &'tcx Local<'tcx>) { - resolve_local(self, Some(&l.pat), l.init, l.els) + resolve_local(self, Some(&l.pat), l.init) } } diff --git a/compiler/rustc_typeck/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs index d0334cd0d..a23575004 100644 --- a/compiler/rustc_typeck/src/check/wfcheck.rs +++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs @@ -1,5 +1,5 @@ -use crate::check::regionck::OutlivesEnvironmentExt; use crate::constrained_generic_params::{identify_constrained_generic_params, Parameter}; +use hir::def::DefKind; use rustc_ast as ast; use rustc_data_structures::fx::{FxHashMap, FxHashSet}; use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed}; @@ -10,22 +10,21 @@ use rustc_hir::ItemKind; use rustc_infer::infer::outlives::env::{OutlivesEnvironment, RegionBoundPairs}; use rustc_infer::infer::outlives::obligations::TypeOutlives; use rustc_infer::infer::{self, InferCtxt, TyCtxtInferExt}; -use rustc_infer::traits::Normalized; +use rustc_middle::mir::ConstraintCategory; use rustc_middle::ty::query::Providers; -use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts, Subst}; use rustc_middle::ty::trait_def::TraitSpecializationKind; use rustc_middle::ty::{ self, AdtKind, DefIdTree, GenericParamDefKind, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitor, }; +use rustc_middle::ty::{GenericArgKind, InternalSubsts}; use rustc_session::parse::feature_err; use rustc_span::symbol::{sym, Ident, Symbol}; use rustc_span::{Span, DUMMY_SP}; use rustc_trait_selection::autoderef::Autoderef; -use rustc_trait_selection::traits::error_reporting::InferCtxtExt; +use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt; +use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _; use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _; -use rustc_trait_selection::traits::query::normalize::AtExt; -use rustc_trait_selection::traits::query::NoSolution; use rustc_trait_selection::traits::{ self, ObligationCause, ObligationCauseCode, ObligationCtxt, WellFormedLoc, }; @@ -72,9 +71,11 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> { ) { let cause = traits::ObligationCause::new(span, self.body_id, ObligationCauseCode::WellFormed(loc)); + // for a type to be WF, we do not need to check if const trait predicates satisfy. + let param_env = self.param_env.without_const(); self.ocx.register_obligation(traits::Obligation::new( cause, - self.param_env, + param_env, ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)).to_predicate(self.tcx()), )); } @@ -86,31 +87,35 @@ pub(super) fn enter_wf_checking_ctxt<'tcx, F>( body_def_id: LocalDefId, f: F, ) where - F: for<'a> FnOnce(&WfCheckingCtxt<'a, 'tcx>) -> FxHashSet<Ty<'tcx>>, + F: for<'a> FnOnce(&WfCheckingCtxt<'a, 'tcx>), { let param_env = tcx.param_env(body_def_id); let body_id = tcx.hir().local_def_id_to_hir_id(body_def_id); - tcx.infer_ctxt().enter(|ref infcx| { - let ocx = ObligationCtxt::new(infcx); - let mut wfcx = WfCheckingCtxt { ocx, span, body_id, param_env }; + let infcx = &tcx.infer_ctxt().build(); + let ocx = ObligationCtxt::new(infcx); - if !tcx.features().trivial_bounds { - wfcx.check_false_global_bounds() - } - let wf_tys = f(&mut wfcx); - let errors = wfcx.select_all_or_error(); - if !errors.is_empty() { - infcx.report_fulfillment_errors(&errors, None, false); - return; - } + let assumed_wf_types = ocx.assumed_wf_types(param_env, span, body_def_id); - let mut outlives_environment = OutlivesEnvironment::new(param_env); - outlives_environment.add_implied_bounds(infcx, wf_tys, body_id); - infcx.check_region_obligations_and_report_errors(body_def_id, &outlives_environment); - }) + let mut wfcx = WfCheckingCtxt { ocx, span, body_id, param_env }; + + if !tcx.features().trivial_bounds { + wfcx.check_false_global_bounds() + } + f(&mut wfcx); + let errors = wfcx.select_all_or_error(); + if !errors.is_empty() { + infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); + return; + } + + let implied_bounds = infcx.implied_bounds_tys(param_env, body_id, assumed_wf_types); + let outlives_environment = + OutlivesEnvironment::with_bounds(param_env, Some(infcx), implied_bounds); + + infcx.check_region_obligations_and_report_errors(body_def_id, &outlives_environment); } -fn check_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) { +fn check_well_formed(tcx: TyCtxt<'_>, def_id: hir::OwnerId) { let node = tcx.hir().expect_owner(def_id); match node { hir::OwnerNode::Crate(_) => {} @@ -142,10 +147,10 @@ fn check_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) { /// the types first. #[instrument(skip(tcx), level = "debug")] fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) { - let def_id = item.def_id; + let def_id = item.owner_id.def_id; debug!( - ?item.def_id, + ?item.owner_id, item.name = ? tcx.def_path_str(def_id.to_def_id()) ); @@ -169,7 +174,7 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) { // for `T` hir::ItemKind::Impl(ref impl_) => { let is_auto = tcx - .impl_trait_ref(item.def_id) + .impl_trait_ref(def_id) .map_or(false, |trait_ref| tcx.trait_is_auto(trait_ref.def_id)); if let (hir::Defaultness::Default { .. }, true) = (impl_.defaultness, is_auto) { let sp = impl_.of_trait.as_ref().map_or(item.span, |t| t.path.span); @@ -205,13 +210,13 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) { } } hir::ItemKind::Fn(ref sig, ..) => { - check_item_fn(tcx, item.def_id, item.ident, item.span, sig.decl); + check_item_fn(tcx, def_id, item.ident, item.span, sig.decl); } hir::ItemKind::Static(ty, ..) => { - check_item_type(tcx, item.def_id, ty.span, false); + check_item_type(tcx, def_id, ty.span, false); } hir::ItemKind::Const(ty, ..) => { - check_item_type(tcx, item.def_id, ty.span, false); + check_item_type(tcx, def_id, ty.span, false); } hir::ItemKind::Struct(ref struct_def, ref ast_generics) => { check_type_defn(tcx, item, false, |wfcx| vec![wfcx.non_enum_variant(struct_def)]); @@ -241,24 +246,24 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) { } fn check_foreign_item(tcx: TyCtxt<'_>, item: &hir::ForeignItem<'_>) { - let def_id = item.def_id; + let def_id = item.owner_id.def_id; debug!( - ?item.def_id, + ?item.owner_id, item.name = ? tcx.def_path_str(def_id.to_def_id()) ); match item.kind { hir::ForeignItemKind::Fn(decl, ..) => { - check_item_fn(tcx, item.def_id, item.ident, item.span, decl) + check_item_fn(tcx, def_id, item.ident, item.span, decl) } - hir::ForeignItemKind::Static(ty, ..) => check_item_type(tcx, item.def_id, ty.span, true), + hir::ForeignItemKind::Static(ty, ..) => check_item_type(tcx, def_id, ty.span, true), hir::ForeignItemKind::Type => (), } } fn check_trait_item(tcx: TyCtxt<'_>, trait_item: &hir::TraitItem<'_>) { - let def_id = trait_item.def_id; + let def_id = trait_item.owner_id.def_id; let (method_sig, span) = match trait_item.kind { hir::TraitItemKind::Fn(ref sig, _) => (Some(sig), trait_item.span), @@ -266,11 +271,11 @@ fn check_trait_item(tcx: TyCtxt<'_>, trait_item: &hir::TraitItem<'_>) { _ => (None, trait_item.span), }; check_object_unsafe_self_trait_by_name(tcx, trait_item); - check_associated_item(tcx, trait_item.def_id, span, method_sig); + check_associated_item(tcx, def_id, span, method_sig); let encl_trait_def_id = tcx.local_parent(def_id); let encl_trait = tcx.hir().expect_item(encl_trait_def_id); - let encl_trait_def_id = encl_trait.def_id.to_def_id(); + let encl_trait_def_id = encl_trait.owner_id.to_def_id(); let fn_lang_item_name = if Some(encl_trait_def_id) == tcx.lang_items().fn_trait() { Some("fn") } else if Some(encl_trait_def_id) == tcx.lang_items().fn_mut_trait() { @@ -343,7 +348,7 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe loop { let mut should_continue = false; for gat_item in associated_items { - let gat_def_id = gat_item.id.def_id; + let gat_def_id = gat_item.id.owner_id; let gat_item = tcx.associated_item(gat_def_id); // If this item is not an assoc ty, or has no substs, then it's not a GAT if gat_item.kind != ty::AssocKind::Type { @@ -360,7 +365,7 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe // constrains the GAT with individually. let mut new_required_bounds: Option<FxHashSet<ty::Predicate<'_>>> = None; for item in associated_items { - let item_def_id = item.id.def_id; + let item_def_id = item.id.owner_id; // Skip our own GAT, since it does not constrain itself at all. if item_def_id == gat_def_id { continue; @@ -383,11 +388,11 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe tcx, param_env, item_hir_id, - sig.output(), + sig.inputs_and_output, // We also assume that all of the function signature's parameter types // are well formed. &sig.inputs().iter().copied().collect(), - gat_def_id, + gat_def_id.def_id, gat_generics, ) } @@ -410,7 +415,7 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe .copied() .collect::<Vec<_>>(), &FxHashSet::default(), - gat_def_id, + gat_def_id.def_id, gat_generics, ) } @@ -450,7 +455,7 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe } for (gat_def_id, required_bounds) in required_bounds_by_item { - let gat_item_hir = tcx.hir().expect_trait_item(gat_def_id); + let gat_item_hir = tcx.hir().expect_trait_item(gat_def_id.def_id); debug!(?required_bounds); let param_env = tcx.param_env(gat_def_id); let gat_hir = gat_item_hir.hir_id(); @@ -658,7 +663,7 @@ fn ty_known_to_outlive<'tcx>( resolve_regions_with_wf_tys(tcx, id, param_env, &wf_tys, |infcx, region_bound_pairs| { let origin = infer::RelateParamBound(DUMMY_SP, ty, None); let outlives = &mut TypeOutlives::new(infcx, tcx, region_bound_pairs, None, param_env); - outlives.type_must_outlive(origin, ty, region); + outlives.type_must_outlive(origin, ty, region, ConstraintCategory::BoringNoLocation); }) } @@ -676,7 +681,12 @@ fn region_known_to_outlive<'tcx>( use rustc_infer::infer::outlives::obligations::TypeOutlivesDelegate; let origin = infer::RelateRegionParamBound(DUMMY_SP); // `region_a: region_b` -> `region_b <= region_a` - infcx.push_sub_region_constraint(origin, region_b, region_a); + infcx.push_sub_region_constraint( + origin, + region_b, + region_a, + ConstraintCategory::BoringNoLocation, + ); }) } @@ -688,26 +698,32 @@ fn resolve_regions_with_wf_tys<'tcx>( id: hir::HirId, param_env: ty::ParamEnv<'tcx>, wf_tys: &FxHashSet<Ty<'tcx>>, - add_constraints: impl for<'a> FnOnce(&'a InferCtxt<'a, 'tcx>, &'a RegionBoundPairs<'tcx>), + add_constraints: impl for<'a> FnOnce(&'a InferCtxt<'tcx>, &'a RegionBoundPairs<'tcx>), ) -> bool { // Unfortunately, we have to use a new `InferCtxt` each call, because // region constraints get added and solved there and we need to test each // call individually. - tcx.infer_ctxt().enter(|infcx| { - let mut outlives_environment = OutlivesEnvironment::new(param_env); - outlives_environment.add_implied_bounds(&infcx, wf_tys.clone(), id); - let region_bound_pairs = outlives_environment.region_bound_pairs(); + let infcx = tcx.infer_ctxt().build(); + let outlives_environment = OutlivesEnvironment::with_bounds( + param_env, + Some(&infcx), + infcx.implied_bounds_tys(param_env, id, wf_tys.clone()), + ); + let region_bound_pairs = outlives_environment.region_bound_pairs(); - add_constraints(&infcx, region_bound_pairs); + add_constraints(&infcx, region_bound_pairs); - let errors = infcx.resolve_regions(&outlives_environment); + infcx.process_registered_region_obligations( + outlives_environment.region_bound_pairs(), + param_env, + ); + let errors = infcx.resolve_regions(&outlives_environment); - debug!(?errors, "errors"); + debug!(?errors, "errors"); - // If we were able to prove that the type outlives the region without - // an error, it must be because of the implied or explicit bounds... - errors.is_empty() - }) + // If we were able to prove that the type outlives the region without + // an error, it must be because of the implied or explicit bounds... + errors.is_empty() } /// TypeVisitor that looks for uses of GATs like @@ -761,7 +777,7 @@ impl<'tcx> TypeVisitor<'tcx> for GATSubstCollector<'tcx> { fn could_be_self(trait_def_id: LocalDefId, ty: &hir::Ty<'_>) -> bool { match ty.kind { hir::TyKind::TraitObject([trait_ref], ..) => match trait_ref.trait_ref.path.segments { - [s] => s.res.and_then(|r| r.opt_def_id()) == Some(trait_def_id.to_def_id()), + [s] => s.res.opt_def_id() == Some(trait_def_id.to_def_id()), _ => false, }, _ => false, @@ -772,9 +788,9 @@ fn could_be_self(trait_def_id: LocalDefId, ty: &hir::Ty<'_>) -> bool { /// When this is done, suggest using `Self` instead. fn check_object_unsafe_self_trait_by_name(tcx: TyCtxt<'_>, item: &hir::TraitItem<'_>) { let (trait_name, trait_def_id) = - match tcx.hir().get_by_def_id(tcx.hir().get_parent_item(item.hir_id())) { + match tcx.hir().get_by_def_id(tcx.hir().get_parent_item(item.hir_id()).def_id) { hir::Node::Item(item) => match item.kind { - hir::ItemKind::Trait(..) => (item.ident, item.def_id), + hir::ItemKind::Trait(..) => (item.ident, item.owner_id), _ => return, }, _ => return, @@ -782,18 +798,18 @@ fn check_object_unsafe_self_trait_by_name(tcx: TyCtxt<'_>, item: &hir::TraitItem let mut trait_should_be_self = vec![]; match &item.kind { hir::TraitItemKind::Const(ty, _) | hir::TraitItemKind::Type(_, Some(ty)) - if could_be_self(trait_def_id, ty) => + if could_be_self(trait_def_id.def_id, ty) => { trait_should_be_self.push(ty.span) } hir::TraitItemKind::Fn(sig, _) => { for ty in sig.decl.inputs { - if could_be_self(trait_def_id, ty) { + if could_be_self(trait_def_id.def_id, ty) { trait_should_be_self.push(ty.span); } } match sig.decl.output { - hir::FnRetTy::Return(ty) if could_be_self(trait_def_id, ty) => { + hir::FnRetTy::Return(ty) if could_be_self(trait_def_id.def_id, ty) => { trait_should_be_self.push(ty.span); } _ => {} @@ -822,16 +838,14 @@ fn check_object_unsafe_self_trait_by_name(tcx: TyCtxt<'_>, item: &hir::TraitItem } fn check_impl_item(tcx: TyCtxt<'_>, impl_item: &hir::ImplItem<'_>) { - let def_id = impl_item.def_id; - let (method_sig, span) = match impl_item.kind { hir::ImplItemKind::Fn(ref sig, _) => (Some(sig), impl_item.span), // Constrain binding and overflow error spans to `<Ty>` in `type foo = <Ty>`. - hir::ImplItemKind::TyAlias(ty) if ty.span != DUMMY_SP => (None, ty.span), + hir::ImplItemKind::Type(ty) if ty.span != DUMMY_SP => (None, ty.span), _ => (None, impl_item.span), }; - check_associated_item(tcx, def_id, span, method_sig); + check_associated_item(tcx, impl_item.owner_id.def_id, span, method_sig); } fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) { @@ -965,7 +979,7 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) { } } -#[tracing::instrument(level = "debug", skip(tcx, span, sig_if_method))] +#[instrument(level = "debug", skip(tcx, span, sig_if_method))] fn check_associated_item( tcx: TyCtxt<'_>, item_id: LocalDefId, @@ -976,15 +990,9 @@ fn check_associated_item( enter_wf_checking_ctxt(tcx, span, item_id, |wfcx| { let item = tcx.associated_item(item_id); - let (mut implied_bounds, self_ty) = match item.container { - ty::TraitContainer => (FxHashSet::default(), tcx.types.self_param), - ty::ImplContainer => { - let def_id = item.container_id(tcx); - ( - impl_implied_bounds(tcx, wfcx.param_env, def_id.expect_local(), span), - tcx.type_of(def_id), - ) - } + let self_ty = match item.container { + ty::TraitContainer => tcx.types.self_param, + ty::ImplContainer => tcx.type_of(item.container_id(tcx)), }; match item.kind { @@ -1002,7 +1010,6 @@ fn check_associated_item( sig, hir_sig.decl, item.def_id.expect_local(), - &mut implied_bounds, ); check_method_receiver(wfcx, hir_sig, item, self_ty); } @@ -1017,8 +1024,6 @@ fn check_associated_item( } } } - - implied_bounds }) } @@ -1040,9 +1045,11 @@ fn check_type_defn<'tcx, F>( ) where F: FnMut(&WfCheckingCtxt<'_, 'tcx>) -> Vec<AdtVariant<'tcx>>, { - enter_wf_checking_ctxt(tcx, item.span, item.def_id, |wfcx| { + let _ = tcx.representability(item.owner_id.def_id); + + enter_wf_checking_ctxt(tcx, item.span, item.owner_id.def_id, |wfcx| { let variants = lookup_fields(wfcx); - let packed = tcx.adt_def(item.def_id).repr().packed(); + let packed = tcx.adt_def(item.owner_id).repr().packed(); for variant in &variants { // All field types must be well-formed. @@ -1066,7 +1073,7 @@ fn check_type_defn<'tcx, F>( // Just treat unresolved type expression as if it needs drop. true } else { - ty.needs_drop(tcx, tcx.param_env(item.def_id)) + ty.needs_drop(tcx, tcx.param_env(item.owner_id)) } } }; @@ -1098,8 +1105,6 @@ fn check_type_defn<'tcx, F>( // Explicit `enum` discriminant values must const-evaluate successfully. if let Some(discr_def_id) = variant.explicit_discr { - let discr_substs = InternalSubsts::identity_for_item(tcx, discr_def_id.to_def_id()); - let cause = traits::ObligationCause::new( tcx.def_span(discr_def_id), wfcx.body_id, @@ -1108,31 +1113,28 @@ fn check_type_defn<'tcx, F>( wfcx.register_obligation(traits::Obligation::new( cause, wfcx.param_env, - ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ty::Unevaluated::new( - ty::WithOptConstParam::unknown(discr_def_id.to_def_id()), - discr_substs, - ))) + ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable( + ty::Const::from_anon_const(tcx, discr_def_id), + )) .to_predicate(tcx), )); } } - check_where_clauses(wfcx, item.span, item.def_id); - - // No implied bounds in a struct definition. - FxHashSet::default() + check_where_clauses(wfcx, item.span, item.owner_id.def_id); }); } #[instrument(skip(tcx, item))] fn check_trait(tcx: TyCtxt<'_>, item: &hir::Item<'_>) { - debug!(?item.def_id); + debug!(?item.owner_id); - let trait_def = tcx.trait_def(item.def_id); + let def_id = item.owner_id.def_id; + let trait_def = tcx.trait_def(def_id); if trait_def.is_marker || matches!(trait_def.specialization_kind, TraitSpecializationKind::Marker) { - for associated_def_id in &*tcx.associated_item_def_ids(item.def_id) { + for associated_def_id in &*tcx.associated_item_def_ids(def_id) { struct_span_err!( tcx.sess, tcx.def_span(*associated_def_id), @@ -1143,10 +1145,8 @@ fn check_trait(tcx: TyCtxt<'_>, item: &hir::Item<'_>) { } } - enter_wf_checking_ctxt(tcx, item.span, item.def_id, |wfcx| { - check_where_clauses(wfcx, item.span, item.def_id); - - FxHashSet::default() + enter_wf_checking_ctxt(tcx, item.span, def_id, |wfcx| { + check_where_clauses(wfcx, item.span, def_id) }); // Only check traits, don't check trait aliases @@ -1186,9 +1186,7 @@ fn check_item_fn( ) { enter_wf_checking_ctxt(tcx, span, def_id, |wfcx| { let sig = tcx.fn_sig(def_id); - let mut implied_bounds = FxHashSet::default(); - check_fn_or_method(wfcx, ident.span, sig, decl, def_id, &mut implied_bounds); - implied_bounds + check_fn_or_method(wfcx, ident.span, sig, decl, def_id); }) } @@ -1231,13 +1229,10 @@ fn check_item_type(tcx: TyCtxt<'_>, item_id: LocalDefId, ty_span: Span, allow_fo tcx.require_lang_item(LangItem::Sync, Some(ty_span)), ); } - - // No implied bounds in a const, etc. - FxHashSet::default() }); } -#[tracing::instrument(level = "debug", skip(tcx, ast_self_ty, ast_trait_ref))] +#[instrument(level = "debug", skip(tcx, ast_self_ty, ast_trait_ref))] fn check_impl<'tcx>( tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>, @@ -1245,13 +1240,13 @@ fn check_impl<'tcx>( ast_trait_ref: &Option<hir::TraitRef<'_>>, constness: hir::Constness, ) { - enter_wf_checking_ctxt(tcx, item.span, item.def_id, |wfcx| { + enter_wf_checking_ctxt(tcx, item.span, item.owner_id.def_id, |wfcx| { match *ast_trait_ref { Some(ref ast_trait_ref) => { // `#[rustc_reservation_impl]` impls are not real impls and // therefore don't need to be WF (the trait's `Self: Trait` predicate // won't hold). - let trait_ref = tcx.impl_trait_ref(item.def_id).unwrap(); + let trait_ref = tcx.impl_trait_ref(item.owner_id).unwrap(); let trait_ref = wfcx.normalize(ast_trait_ref.path.span, None, trait_ref); let trait_pred = ty::TraitPredicate { trait_ref, @@ -1273,19 +1268,21 @@ fn check_impl<'tcx>( wfcx.register_obligations(obligations); } None => { - let self_ty = tcx.type_of(item.def_id); - let self_ty = wfcx.normalize(item.span, None, self_ty); + let self_ty = tcx.type_of(item.owner_id); + let self_ty = wfcx.normalize( + item.span, + Some(WellFormedLoc::Ty(item.hir_id().expect_owner().def_id)), + self_ty, + ); wfcx.register_wf_obligation( ast_self_ty.span, - Some(WellFormedLoc::Ty(item.hir_id().expect_owner())), + Some(WellFormedLoc::Ty(item.hir_id().expect_owner().def_id)), self_ty.into(), ); } } - check_where_clauses(wfcx, item.span, item.def_id); - - impl_implied_bounds(tcx, wfcx.param_env, item.def_id, item.span) + check_where_clauses(wfcx, item.span, item.owner_id.def_id); }); } @@ -1321,7 +1318,11 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id // parameter includes another (e.g., `<T, U = T>`). In those cases, we can't // be sure if it will error or not as user might always specify the other. if !ty.needs_subst() { - wfcx.register_wf_obligation(tcx.def_span(param.def_id), None, ty.into()); + wfcx.register_wf_obligation( + tcx.def_span(param.def_id), + Some(WellFormedLoc::Ty(param.def_id.expect_local())), + ty.into(), + ); } } } @@ -1426,9 +1427,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id let substituted_pred = predicates.rebind(pred).subst(tcx, substs); // Don't check non-defaulted params, dependent defaults (including lifetimes) // or preds with multiple params. - if substituted_pred.has_param_types_or_consts() - || param_count.params.len() > 1 - || has_region + if substituted_pred.has_non_region_param() || param_count.params.len() > 1 || has_region { None } else if predicates.0.predicates.iter().any(|&(p, _)| p == substituted_pred) { @@ -1465,21 +1464,26 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id assert_eq!(predicates.predicates.len(), predicates.spans.len()); let wf_obligations = iter::zip(&predicates.predicates, &predicates.spans).flat_map(|(&p, &sp)| { - traits::wf::predicate_obligations(infcx, wfcx.param_env, wfcx.body_id, p, sp) + traits::wf::predicate_obligations( + infcx, + wfcx.param_env.without_const(), + wfcx.body_id, + p, + sp, + ) }); let obligations: Vec<_> = wf_obligations.chain(default_obligations).collect(); wfcx.register_obligations(obligations); } -#[tracing::instrument(level = "debug", skip(wfcx, span, hir_decl))] +#[instrument(level = "debug", skip(wfcx, span, hir_decl))] fn check_fn_or_method<'tcx>( wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, sig: ty::PolyFnSig<'tcx>, hir_decl: &hir::FnDecl<'_>, def_id: LocalDefId, - implied_bounds: &mut FxHashSet<Ty<'tcx>>, ) { let tcx = wfcx.tcx(); let sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), sig); @@ -1521,23 +1525,66 @@ fn check_fn_or_method<'tcx>( ); } - implied_bounds.extend(sig.inputs()); - - wfcx.register_wf_obligation(hir_decl.output.span(), None, sig.output().into()); + wfcx.register_wf_obligation( + hir_decl.output.span(), + Some(WellFormedLoc::Param { + function: def_id, + param_idx: sig.inputs().len().try_into().unwrap(), + }), + sig.output().into(), + ); - // FIXME(#27579) return types should not be implied bounds - implied_bounds.insert(sig.output()); + check_where_clauses(wfcx, span, def_id); - debug!(?implied_bounds); + check_return_position_impl_trait_in_trait_bounds( + tcx, + wfcx, + def_id, + sig.output(), + hir_decl.output.span(), + ); +} - check_where_clauses(wfcx, span, def_id); +/// Basically `check_associated_type_bounds`, but separated for now and should be +/// deduplicated when RPITITs get lowered into real associated items. +fn check_return_position_impl_trait_in_trait_bounds<'tcx>( + tcx: TyCtxt<'tcx>, + wfcx: &WfCheckingCtxt<'_, 'tcx>, + fn_def_id: LocalDefId, + fn_output: Ty<'tcx>, + span: Span, +) { + if let Some(assoc_item) = tcx.opt_associated_item(fn_def_id.to_def_id()) + && assoc_item.container == ty::AssocItemContainer::TraitContainer + { + for arg in fn_output.walk() { + if let ty::GenericArgKind::Type(ty) = arg.unpack() + && let ty::Projection(proj) = ty.kind() + && tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder + && tcx.impl_trait_in_trait_parent(proj.item_def_id) == fn_def_id.to_def_id() + { + let bounds = wfcx.tcx().explicit_item_bounds(proj.item_def_id); + let wf_obligations = bounds.iter().flat_map(|&(bound, bound_span)| { + let normalized_bound = wfcx.normalize(span, None, bound); + traits::wf::predicate_obligations( + wfcx.infcx, + wfcx.param_env, + wfcx.body_id, + normalized_bound, + bound_span, + ) + }); + wfcx.register_obligations(wf_obligations); + } + } + } } const HELP_FOR_SELF_TYPE: &str = "consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, \ `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one \ of the previous types except `Self`)"; -#[tracing::instrument(level = "debug", skip(wfcx))] +#[instrument(level = "debug", skip(wfcx))] fn check_method_receiver<'tcx>( wfcx: &WfCheckingCtxt<'_, 'tcx>, fn_sig: &hir::FnSig<'_>, @@ -1629,7 +1676,7 @@ fn receiver_is_valid<'tcx>( // `self: Self` is always valid. if can_eq_self(receiver_ty) { if let Err(err) = wfcx.equate_types(&cause, wfcx.param_env, self_ty, receiver_ty) { - infcx.report_mismatched_types(&cause, self_ty, receiver_ty, err).emit(); + infcx.err_ctxt().report_mismatched_types(&cause, self_ty, receiver_ty, err).emit(); } return true; } @@ -1661,7 +1708,10 @@ fn receiver_is_valid<'tcx>( if let Err(err) = wfcx.equate_types(&cause, wfcx.param_env, self_ty, potential_self_ty) { - infcx.report_mismatched_types(&cause, self_ty, potential_self_ty, err).emit(); + infcx + .err_ctxt() + .report_mismatched_types(&cause, self_ty, potential_self_ty, err) + .emit(); } break; @@ -1728,14 +1778,14 @@ fn check_variances_for_type_defn<'tcx>( item: &hir::Item<'tcx>, hir_generics: &hir::Generics<'_>, ) { - let ty = tcx.type_of(item.def_id); + let ty = tcx.type_of(item.owner_id); if tcx.has_error_field(ty) { return; } - let ty_predicates = tcx.predicates_of(item.def_id); + let ty_predicates = tcx.predicates_of(item.owner_id); assert_eq!(ty_predicates.parent, None); - let variances = tcx.variances_of(item.def_id); + let variances = tcx.variances_of(item.owner_id); let mut constrained_parameters: FxHashSet<_> = variances .iter() @@ -1748,7 +1798,7 @@ fn check_variances_for_type_defn<'tcx>( // Lazily calculated because it is only needed in case of an error. let explicitly_bounded_params = LazyCell::new(|| { - let icx = crate::collect::ItemCtxt::new(tcx, item.def_id.to_def_id()); + let icx = crate::collect::ItemCtxt::new(tcx, item.owner_id.to_def_id()); hir_generics .predicates .iter() @@ -1817,6 +1867,7 @@ fn report_bivariance( impl<'tcx> WfCheckingCtxt<'_, 'tcx> { /// Feature gates RFC 2056 -- trivial bounds, checking for global bounds that /// aren't true. + #[instrument(level = "debug", skip(self))] fn check_false_global_bounds(&mut self) { let tcx = self.ocx.infcx.tcx; let mut span = self.span; @@ -1868,10 +1919,10 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> { fn check_mod_type_wf(tcx: TyCtxt<'_>, module: LocalDefId) { let items = tcx.hir_module_items(module); - items.par_items(|item| tcx.ensure().check_well_formed(item.def_id)); - items.par_impl_items(|item| tcx.ensure().check_well_formed(item.def_id)); - items.par_trait_items(|item| tcx.ensure().check_well_formed(item.def_id)); - items.par_foreign_items(|item| tcx.ensure().check_well_formed(item.def_id)); + items.par_items(|item| tcx.ensure().check_well_formed(item.owner_id)); + items.par_impl_items(|item| tcx.ensure().check_well_formed(item.owner_id)); + items.par_trait_items(|item| tcx.ensure().check_well_formed(item.owner_id)); + items.par_foreign_items(|item| tcx.ensure().check_well_formed(item.owner_id)); } /////////////////////////////////////////////////////////////////////////// @@ -1924,40 +1975,6 @@ impl<'a, 'tcx> WfCheckingCtxt<'a, 'tcx> { } } -pub fn impl_implied_bounds<'tcx>( - tcx: TyCtxt<'tcx>, - param_env: ty::ParamEnv<'tcx>, - impl_def_id: LocalDefId, - span: Span, -) -> FxHashSet<Ty<'tcx>> { - // We completely ignore any obligations caused by normalizing the types - // we assume to be well formed. Considering that the user of the implied - // bounds will also normalize them, we leave it to them to emit errors - // which should result in better causes and spans. - tcx.infer_ctxt().enter(|infcx| { - let cause = ObligationCause::misc(span, tcx.hir().local_def_id_to_hir_id(impl_def_id)); - match tcx.impl_trait_ref(impl_def_id) { - Some(trait_ref) => { - // Trait impl: take implied bounds from all types that - // appear in the trait reference. - match infcx.at(&cause, param_env).normalize(trait_ref) { - Ok(Normalized { value, obligations: _ }) => value.substs.types().collect(), - Err(NoSolution) => FxHashSet::default(), - } - } - - None => { - // Inherent impl: take implied bounds from the `self` type. - let self_ty = tcx.type_of(impl_def_id); - match infcx.at(&cause, param_env).normalize(self_ty) { - Ok(Normalized { value, obligations: _ }) => FxHashSet::from_iter([value]), - Err(NoSolution) => FxHashSet::default(), - } - } - } - }) -} - fn error_392( tcx: TyCtxt<'_>, span: Span, diff --git a/compiler/rustc_hir_analysis/src/check_unused.rs b/compiler/rustc_hir_analysis/src/check_unused.rs new file mode 100644 index 000000000..d0c317334 --- /dev/null +++ b/compiler/rustc_hir_analysis/src/check_unused.rs @@ -0,0 +1,192 @@ +use crate::errors::{ExternCrateNotIdiomatic, UnusedExternCrate}; +use rustc_data_structures::fx::FxHashMap; +use rustc_data_structures::unord::UnordSet; +use rustc_hir as hir; +use rustc_hir::def::DefKind; +use rustc_hir::def_id::{DefId, LocalDefId}; +use rustc_middle::ty::TyCtxt; +use rustc_session::lint; +use rustc_span::{Span, Symbol}; + +pub fn check_crate(tcx: TyCtxt<'_>) { + let mut used_trait_imports: UnordSet<LocalDefId> = Default::default(); + + for item_def_id in tcx.hir().body_owners() { + let imports = tcx.used_trait_imports(item_def_id); + debug!("GatherVisitor: item_def_id={:?} with imports {:#?}", item_def_id, imports); + used_trait_imports.extend(imports.items().copied()); + } + + for &id in tcx.maybe_unused_trait_imports(()) { + debug_assert_eq!(tcx.def_kind(id), DefKind::Use); + if tcx.visibility(id).is_public() { + continue; + } + if used_trait_imports.contains(&id) { + continue; + } + let item = tcx.hir().expect_item(id); + if item.span.is_dummy() { + continue; + } + let hir::ItemKind::Use(path, _) = item.kind else { unreachable!() }; + let msg = if let Ok(snippet) = tcx.sess.source_map().span_to_snippet(path.span) { + format!("unused import: `{}`", snippet) + } else { + "unused import".to_owned() + }; + tcx.struct_span_lint_hir( + lint::builtin::UNUSED_IMPORTS, + item.hir_id(), + path.span, + msg, + |lint| lint, + ); + } + + unused_crates_lint(tcx); +} + +fn unused_crates_lint(tcx: TyCtxt<'_>) { + let lint = lint::builtin::UNUSED_EXTERN_CRATES; + + // Collect first the crates that are completely unused. These we + // can always suggest removing (no matter which edition we are + // in). + let unused_extern_crates: FxHashMap<LocalDefId, Span> = tcx + .maybe_unused_extern_crates(()) + .iter() + .filter(|&&(def_id, _)| { + // The `def_id` here actually was calculated during resolution (at least + // at the time of this writing) and is being shipped to us via a side + // channel of the tcx. There may have been extra expansion phases, + // however, which ended up removing the `def_id` *after* expansion. + // + // As a result we need to verify that `def_id` is indeed still valid for + // our AST and actually present in the HIR map. If it's not there then + // there's safely nothing to warn about, and otherwise we carry on with + // our execution. + // + // Note that if we carry through to the `extern_mod_stmt_cnum` query + // below it'll cause a panic because `def_id` is actually bogus at this + // point in time otherwise. + if tcx.hir().find(tcx.hir().local_def_id_to_hir_id(def_id)).is_none() { + return false; + } + true + }) + .filter(|&&(def_id, _)| { + tcx.extern_mod_stmt_cnum(def_id).map_or(true, |cnum| { + !tcx.is_compiler_builtins(cnum) + && !tcx.is_panic_runtime(cnum) + && !tcx.has_global_allocator(cnum) + && !tcx.has_panic_handler(cnum) + }) + }) + .cloned() + .collect(); + + // Collect all the extern crates (in a reliable order). + let mut crates_to_lint = vec![]; + + for id in tcx.hir().items() { + if matches!(tcx.def_kind(id.owner_id), DefKind::ExternCrate) { + let item = tcx.hir().item(id); + if let hir::ItemKind::ExternCrate(orig_name) = item.kind { + crates_to_lint.push(ExternCrateToLint { + def_id: item.owner_id.to_def_id(), + span: item.span, + orig_name, + warn_if_unused: !item.ident.as_str().starts_with('_'), + }); + } + } + } + + let extern_prelude = &tcx.resolutions(()).extern_prelude; + + for extern_crate in &crates_to_lint { + let def_id = extern_crate.def_id.expect_local(); + let item = tcx.hir().expect_item(def_id); + + // If the crate is fully unused, we suggest removing it altogether. + // We do this in any edition. + if extern_crate.warn_if_unused { + if let Some(&span) = unused_extern_crates.get(&def_id) { + // Removal suggestion span needs to include attributes (Issue #54400) + let id = tcx.hir().local_def_id_to_hir_id(def_id); + let span_with_attrs = tcx + .hir() + .attrs(id) + .iter() + .map(|attr| attr.span) + .fold(span, |acc, attr_span| acc.to(attr_span)); + + tcx.emit_spanned_lint(lint, id, span, UnusedExternCrate { span: span_with_attrs }); + continue; + } + } + + // If we are not in Rust 2018 edition, then we don't make any further + // suggestions. + if !tcx.sess.rust_2018() { + continue; + } + + // If the extern crate isn't in the extern prelude, + // there is no way it can be written as a `use`. + let orig_name = extern_crate.orig_name.unwrap_or(item.ident.name); + if !extern_prelude.get(&orig_name).map_or(false, |from_item| !from_item) { + continue; + } + + // If the extern crate is renamed, then we cannot suggest replacing it with a use as this + // would not insert the new name into the prelude, where other imports in the crate may be + // expecting it. + if extern_crate.orig_name.is_some() { + continue; + } + + let id = tcx.hir().local_def_id_to_hir_id(def_id); + // If the extern crate has any attributes, they may have funky + // semantics we can't faithfully represent using `use` (most + // notably `#[macro_use]`). Ignore it. + if !tcx.hir().attrs(id).is_empty() { + continue; + } + + let base_replacement = match extern_crate.orig_name { + Some(orig_name) => format!("use {} as {};", orig_name, item.ident.name), + None => format!("use {};", item.ident.name), + }; + let vis = tcx.sess.source_map().span_to_snippet(item.vis_span).unwrap_or_default(); + let add_vis = |to| if vis.is_empty() { to } else { format!("{} {}", vis, to) }; + tcx.emit_spanned_lint( + lint, + id, + extern_crate.span, + ExternCrateNotIdiomatic { + span: extern_crate.span, + msg_code: add_vis("use".to_string()), + suggestion_code: add_vis(base_replacement), + }, + ); + } +} + +struct ExternCrateToLint { + /// `DefId` of the extern crate + def_id: DefId, + + /// span from the item + span: Span, + + /// if `Some`, then this is renamed (`extern crate orig_name as + /// crate_name`), and -- perhaps surprisingly -- this stores the + /// *original* name (`item.name` will contain the new name) + orig_name: Option<Symbol>, + + /// if `false`, the original name started with `_`, so we shouldn't lint + /// about it going unused (but we should still emit idiom lints). + warn_if_unused: bool, +} |