| 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() |
| } |
