| use crate::check::intrinsicck::InlineAsmCtxt; |
| |
| use super::compare_impl_item::check_type_bounds; |
| use super::compare_impl_item::{compare_impl_method, compare_impl_ty}; |
| use super::*; |
| use rustc_attr as attr; |
| use rustc_data_structures::unord::{UnordMap, UnordSet}; |
| use rustc_errors::{codes::*, MultiSpan}; |
| use rustc_hir as hir; |
| use rustc_hir::def::{CtorKind, DefKind}; |
| use rustc_hir::Node; |
| use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt}; |
| use rustc_infer::traits::Obligation; |
| use rustc_lint_defs::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS; |
| use rustc_middle::middle::resolve_bound_vars::ResolvedArg; |
| use rustc_middle::middle::stability::EvalResult; |
| use rustc_middle::ty::fold::BottomUpFolder; |
| use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES}; |
| use rustc_middle::ty::util::{Discr, InspectCoroutineFields, IntTypeExt}; |
| use rustc_middle::ty::GenericArgKind; |
| use rustc_middle::ty::{ |
| AdtDef, ParamEnv, RegionKind, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, |
| }; |
| use rustc_session::lint::builtin::{UNINHABITED_STATIC, UNSUPPORTED_CALLING_CONVENTIONS}; |
| use rustc_target::abi::FieldIdx; |
| use rustc_trait_selection::traits; |
| use rustc_trait_selection::traits::error_reporting::on_unimplemented::OnUnimplementedDirective; |
| use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _; |
| use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _; |
| use rustc_type_ir::fold::TypeFoldable; |
| |
| use std::cell::LazyCell; |
| 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_code_err!( |
| tcx.dcx(), |
| span, |
| E0570, |
| "`{abi}` is not a supported ABI for the current target", |
| ) |
| .emit(); |
| } |
| None => { |
| tcx.node_span_lint( |
| UNSUPPORTED_CALLING_CONVENTIONS, |
| hir_id, |
| span, |
| "use of calling convention not supported on this target", |
| |_| {}, |
| ); |
| } |
| } |
| |
| // This ABI is only allowed on function pointers |
| if abi == Abi::CCmseNonSecureCall { |
| struct_span_code_err!( |
| tcx.dcx(), |
| 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, def); |
| check_packed(tcx, span, def); |
| check_unnamed_fields(tcx, 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, def); |
| check_union_fields(tcx, span, def_id); |
| check_packed(tcx, span, def); |
| check_unnamed_fields(tcx, def); |
| } |
| |
| /// Check the representation of adts with unnamed fields. |
| fn check_unnamed_fields(tcx: TyCtxt<'_>, def: ty::AdtDef<'_>) { |
| if def.is_enum() { |
| return; |
| } |
| let variant = def.non_enum_variant(); |
| if !variant.has_unnamed_fields() { |
| return; |
| } |
| if !def.is_anonymous() { |
| let adt_kind = def.descr(); |
| let span = tcx.def_span(def.did()); |
| let unnamed_fields = variant |
| .fields |
| .iter() |
| .filter(|f| f.is_unnamed()) |
| .map(|f| { |
| let span = tcx.def_span(f.did); |
| errors::UnnamedFieldsReprFieldDefined { span } |
| }) |
| .collect::<Vec<_>>(); |
| debug_assert_ne!(unnamed_fields.len(), 0, "expect unnamed fields in this adt"); |
| let adt_name = tcx.item_name(def.did()); |
| if !def.repr().c() { |
| tcx.dcx().emit_err(errors::UnnamedFieldsRepr::MissingReprC { |
| span, |
| adt_kind, |
| adt_name, |
| unnamed_fields, |
| sugg_span: span.shrink_to_lo(), |
| }); |
| } |
| } |
| for field in variant.fields.iter().filter(|f| f.is_unnamed()) { |
| let field_ty = tcx.type_of(field.did).instantiate_identity(); |
| if let Some(adt) = field_ty.ty_adt_def() |
| && !adt.is_enum() |
| { |
| if !adt.is_anonymous() && !adt.repr().c() { |
| let field_ty_span = tcx.def_span(adt.did()); |
| tcx.dcx().emit_err(errors::UnnamedFieldsRepr::FieldMissingReprC { |
| span: tcx.def_span(field.did), |
| field_ty_span, |
| field_ty, |
| field_adt_kind: adt.descr(), |
| sugg_span: field_ty_span.shrink_to_lo(), |
| }); |
| } |
| } else { |
| tcx.dcx().emit_err(errors::InvalidUnnamedFieldTy { span: tcx.def_span(field.did) }); |
| } |
| } |
| } |
| |
| /// 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).instantiate_identity(); |
| if let ty::Adt(def, args) = item_type.kind() { |
| assert!(def.is_union()); |
| |
| fn allowed_union_field<'tcx>( |
| ty: Ty<'tcx>, |
| tcx: TyCtxt<'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| ) -> 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)) |
| } |
| ty::Array(elem, _len) => { |
| // Like `Copy`, we do *not* special-case length 0. |
| allowed_union_field(*elem, tcx, param_env) |
| } |
| _ => { |
| // Fallback case: allow `ManuallyDrop` and things that are `Copy`, |
| // also no need to report an error if the type is unresolved. |
| ty.ty_adt_def().is_some_and(|adt_def| adt_def.is_manually_drop()) |
| || ty.is_copy_modulo_regions(tcx, param_env) |
| || ty.references_error() |
| } |
| } |
| } |
| |
| let param_env = tcx.param_env(item_def_id); |
| for field in &def.non_enum_variant().fields { |
| let Ok(field_ty) = tcx.try_normalize_erasing_regions(param_env, field.ty(tcx, args)) |
| else { |
| tcx.dcx().span_delayed_bug(span, "could not normalize field type"); |
| continue; |
| }; |
| |
| if !allowed_union_field(field_ty, tcx, param_env) { |
| 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"), |
| }; |
| tcx.dcx().emit_err(errors::InvalidUnionField { |
| field_span, |
| sugg: errors::InvalidUnionFieldSuggestion { |
| lo: ty_span.shrink_to_lo(), |
| hi: ty_span.shrink_to_hi(), |
| }, |
| note: (), |
| }); |
| 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.dcx() |
| .span_delayed_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: TyCtxt<'_>, 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).instantiate_identity(); |
| 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 matches!(tcx.def_kind(def_id), DefKind::Static{ .. } |
| if tcx.def_kind(tcx.local_parent(def_id)) == DefKind::ForeignMod) => |
| { |
| tcx.dcx().emit_err(errors::TooLargeStatic { span }); |
| return; |
| } |
| // Generic statics are rejected, but we still reach this case. |
| Err(e) => { |
| tcx.dcx().span_delayed_bug(span, format!("{e:?}")); |
| return; |
| } |
| }; |
| if layout.abi.is_uninhabited() { |
| tcx.node_span_lint( |
| UNINHABITED_STATIC, |
| tcx.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: TyCtxt<'_>, def_id: LocalDefId) { |
| let item = tcx.hir().expect_item(def_id); |
| let hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) = item.kind else { |
| tcx.dcx().span_bug(item.span, "expected opaque item"); |
| }; |
| |
| // 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 span = tcx.def_span(item.owner_id.def_id); |
| |
| if tcx.type_of(item.owner_id.def_id).instantiate_identity().references_error() { |
| return; |
| } |
| if check_opaque_for_cycles(tcx, item.owner_id.def_id, span).is_err() { |
| return; |
| } |
| |
| let _ = check_opaque_meets_bounds(tcx, item.owner_id.def_id, span, origin); |
| } |
| |
| /// Checks that an opaque type does not contain cycles. |
| pub(super) fn check_opaque_for_cycles<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| def_id: LocalDefId, |
| span: Span, |
| ) -> Result<(), ErrorGuaranteed> { |
| let args = GenericArgs::identity_for_item(tcx, def_id); |
| |
| // First, try to look at any opaque expansion cycles, considering coroutine fields |
| // (even though these aren't necessarily true errors). |
| if tcx |
| .try_expand_impl_trait_type(def_id.to_def_id(), args, InspectCoroutineFields::Yes) |
| .is_err() |
| { |
| // Look for true opaque expansion cycles, but ignore coroutines. |
| // This will give us any true errors. Coroutines are only problematic |
| // if they cause layout computation errors. |
| if tcx |
| .try_expand_impl_trait_type(def_id.to_def_id(), args, InspectCoroutineFields::No) |
| .is_err() |
| { |
| let reported = opaque_type_cycle_error(tcx, def_id, span); |
| return Err(reported); |
| } |
| |
| // And also look for cycle errors in the layout of coroutines. |
| if let Err(&LayoutError::Cycle(guar)) = |
| tcx.layout_of(tcx.param_env(def_id).and(Ty::new_opaque(tcx, def_id.to_def_id(), args))) |
| { |
| return Err(guar); |
| } |
| } |
| |
| 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, |
| span: Span, |
| origin: &hir::OpaqueTyOrigin, |
| ) -> Result<(), ErrorGuaranteed> { |
| let defining_use_anchor = match *origin { |
| hir::OpaqueTyOrigin::FnReturn(did) |
| | hir::OpaqueTyOrigin::AsyncFn(did) |
| | hir::OpaqueTyOrigin::TyAlias { parent: did, .. } => did, |
| }; |
| let param_env = tcx.param_env(defining_use_anchor); |
| |
| let infcx = tcx.infer_ctxt().with_opaque_type_inference(defining_use_anchor).build(); |
| let ocx = ObligationCtxt::new(&infcx); |
| |
| let args = match *origin { |
| hir::OpaqueTyOrigin::FnReturn(parent) |
| | hir::OpaqueTyOrigin::AsyncFn(parent) |
| | hir::OpaqueTyOrigin::TyAlias { parent, .. } => GenericArgs::identity_for_item( |
| tcx, parent, |
| ) |
| .extend_to(tcx, def_id.to_def_id(), |param, _| { |
| tcx.map_opaque_lifetime_to_parent_lifetime(param.def_id.expect_local()).into() |
| }), |
| }; |
| |
| let opaque_ty = Ty::new_opaque(tcx, def_id.to_def_id(), args); |
| |
| // `ReErased` regions appear in the "parent_args" of closures/coroutines. |
| // We're ignoring them here and replacing them with fresh region variables. |
| // See tests in ui/type-alias-impl-trait/closure_{parent_args,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.type_of(def_id.to_def_id()).instantiate(tcx, args); |
| 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, def_id); |
| |
| match ocx.eq(&misc_cause, param_env, opaque_ty, hidden_ty) { |
| Ok(()) => {} |
| Err(ty_err) => { |
| // Some types may be left "stranded" if they can't be reached |
| // from a lowered rustc_middle bound but they're mentioned in the HIR. |
| // This will happen, e.g., when a nested opaque is inside of a non- |
| // existent associated type, like `impl Trait<Missing = impl Trait>`. |
| // See <tests/ui/impl-trait/stranded-opaque.rs>. |
| let ty_err = ty_err.to_string(tcx); |
| let guar = tcx.dcx().span_delayed_bug( |
| span, |
| format!("could not unify `{hidden_ty}` with revealed type:\n{ty_err}"), |
| ); |
| return Err(guar); |
| } |
| } |
| |
| // 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::Clause(ty::ClauseKind::WellFormed(hidden_ty.into()))); |
| ocx.register_obligation(Obligation::new(tcx, misc_cause.clone(), 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 guar = infcx.err_ctxt().report_fulfillment_errors(errors); |
| return Err(guar); |
| } |
| |
| let wf_tys = ocx.assumed_wf_types_and_report_errors(param_env, defining_use_anchor)?; |
| let implied_bounds = infcx.implied_bounds_tys(param_env, def_id, &wf_tys); |
| let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds); |
| ocx.resolve_regions_and_report_errors(defining_use_anchor, &outlives_env)?; |
| |
| if let hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) = origin { |
| // HACK: this should also fall through to the hidden type check below, but the original |
| // implementation had a bug where equivalent lifetimes are not identical. This caused us |
| // to reject existing stable code that is otherwise completely fine. The real fix is to |
| // compare the hidden types via our type equivalence/relation infra instead of doing an |
| // identity check. |
| let _ = infcx.take_opaque_types(); |
| Ok(()) |
| } else { |
| // Check that any hidden types found during wf checking match the hidden types that `type_of` sees. |
| for (mut key, mut ty) in infcx.take_opaque_types() { |
| ty.hidden_type.ty = infcx.resolve_vars_if_possible(ty.hidden_type.ty); |
| key = infcx.resolve_vars_if_possible(key); |
| sanity_check_found_hidden_type(tcx, key, ty.hidden_type)?; |
| } |
| Ok(()) |
| } |
| } |
| |
| fn sanity_check_found_hidden_type<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| key: ty::OpaqueTypeKey<'tcx>, |
| mut ty: ty::OpaqueHiddenType<'tcx>, |
| ) -> Result<(), ErrorGuaranteed> { |
| if ty.ty.is_ty_var() { |
| // Nothing was actually constrained. |
| return Ok(()); |
| } |
| if let ty::Alias(ty::Opaque, alias) = ty.ty.kind() { |
| if alias.def_id == key.def_id.to_def_id() && alias.args == key.args { |
| // Nothing was actually constrained, this is an opaque usage that was |
| // only discovered to be opaque after inference vars resolved. |
| return Ok(()); |
| } |
| } |
| let strip_vars = |ty: Ty<'tcx>| { |
| ty.fold_with(&mut BottomUpFolder { |
| tcx, |
| ty_op: |t| t, |
| ct_op: |c| c, |
| lt_op: |l| match l.kind() { |
| RegionKind::ReVar(_) => tcx.lifetimes.re_erased, |
| _ => l, |
| }, |
| }) |
| }; |
| // Closures frequently end up containing erased lifetimes in their final representation. |
| // These correspond to lifetime variables that never got resolved, so we patch this up here. |
| ty.ty = strip_vars(ty.ty); |
| // Get the hidden type. |
| let hidden_ty = tcx.type_of(key.def_id).instantiate(tcx, key.args); |
| let hidden_ty = strip_vars(hidden_ty); |
| |
| // If the hidden types differ, emit a type mismatch diagnostic. |
| if hidden_ty == ty.ty { |
| Ok(()) |
| } else { |
| let span = tcx.def_span(key.def_id); |
| let other = ty::OpaqueHiddenType { ty: hidden_ty, span }; |
| Err(ty.build_mismatch_error(&other, key.def_id, tcx)?.emit()) |
| } |
| } |
| |
| /// Check that the opaque's precise captures list is valid (if present). |
| /// We check this for regular `impl Trait`s and also RPITITs, even though the latter |
| /// are technically GATs. |
| /// |
| /// This function is responsible for: |
| /// 1. Checking that all type/const params are mention in the captures list. |
| /// 2. Checking that all lifetimes that are implicitly captured are mentioned. |
| /// 3. Asserting that all parameters mentioned in the captures list are invariant. |
| fn check_opaque_precise_captures<'tcx>(tcx: TyCtxt<'tcx>, opaque_def_id: LocalDefId) { |
| let hir::OpaqueTy { precise_capturing_args, .. } = |
| *tcx.hir_node_by_def_id(opaque_def_id).expect_item().expect_opaque_ty(); |
| let Some(precise_capturing_args) = precise_capturing_args else { |
| // No precise capturing args; nothing to validate |
| return; |
| }; |
| |
| let mut expected_captures = UnordSet::default(); |
| let mut shadowed_captures = UnordSet::default(); |
| let mut seen_params = UnordMap::default(); |
| let mut prev_non_lifetime_param = None; |
| for arg in precise_capturing_args { |
| let (hir_id, ident) = match *arg { |
| hir::PreciseCapturingArg::Param(hir::PreciseCapturingNonLifetimeArg { |
| hir_id, |
| ident, |
| .. |
| }) => { |
| if prev_non_lifetime_param.is_none() { |
| prev_non_lifetime_param = Some(ident); |
| } |
| (hir_id, ident) |
| } |
| hir::PreciseCapturingArg::Lifetime(&hir::Lifetime { hir_id, ident, .. }) => { |
| if let Some(prev_non_lifetime_param) = prev_non_lifetime_param { |
| tcx.dcx().emit_err(errors::LifetimesMustBeFirst { |
| lifetime_span: ident.span, |
| name: ident.name, |
| other_span: prev_non_lifetime_param.span, |
| }); |
| } |
| (hir_id, ident) |
| } |
| }; |
| |
| let ident = ident.normalize_to_macros_2_0(); |
| if let Some(span) = seen_params.insert(ident, ident.span) { |
| tcx.dcx().emit_err(errors::DuplicatePreciseCapture { |
| name: ident.name, |
| first_span: span, |
| second_span: ident.span, |
| }); |
| } |
| |
| match tcx.named_bound_var(hir_id) { |
| Some(ResolvedArg::EarlyBound(def_id)) => { |
| expected_captures.insert(def_id); |
| |
| // Make sure we allow capturing these lifetimes through `Self` and |
| // `T::Assoc` projection syntax, too. These will occur when we only |
| // see lifetimes are captured after hir-lowering -- this aligns with |
| // the cases that were stabilized with the `impl_trait_projection` |
| // feature -- see <https://github.com/rust-lang/rust/pull/115659>. |
| if let DefKind::LifetimeParam = tcx.def_kind(def_id) |
| && let ty::ReEarlyParam(ty::EarlyParamRegion { def_id, .. }) |
| | ty::ReLateParam(ty::LateParamRegion { |
| bound_region: ty::BoundRegionKind::BrNamed(def_id, _), |
| .. |
| }) = *tcx.map_opaque_lifetime_to_parent_lifetime(def_id.expect_local()) |
| { |
| shadowed_captures.insert(def_id); |
| } |
| } |
| _ => { |
| tcx.dcx().span_delayed_bug( |
| tcx.hir().span(hir_id), |
| "parameter should have been resolved", |
| ); |
| } |
| } |
| } |
| |
| let variances = tcx.variances_of(opaque_def_id); |
| let mut def_id = Some(opaque_def_id.to_def_id()); |
| while let Some(generics) = def_id { |
| let generics = tcx.generics_of(generics); |
| def_id = generics.parent; |
| |
| for param in &generics.own_params { |
| if expected_captures.contains(¶m.def_id) { |
| assert_eq!( |
| variances[param.index as usize], |
| ty::Invariant, |
| "precise captured param should be invariant" |
| ); |
| continue; |
| } |
| // If a param is shadowed by a early-bound (duplicated) lifetime, then |
| // it may or may not be captured as invariant, depending on if it shows |
| // up through `Self` or `T::Assoc` syntax. |
| if shadowed_captures.contains(¶m.def_id) { |
| continue; |
| } |
| |
| match param.kind { |
| ty::GenericParamDefKind::Lifetime => { |
| let use_span = tcx.def_span(param.def_id); |
| let opaque_span = tcx.def_span(opaque_def_id); |
| // Check if the lifetime param was captured but isn't named in the precise captures list. |
| if variances[param.index as usize] == ty::Invariant { |
| if let DefKind::OpaqueTy = tcx.def_kind(tcx.parent(param.def_id)) |
| && let ty::ReEarlyParam(ty::EarlyParamRegion { def_id, .. }) |
| | ty::ReLateParam(ty::LateParamRegion { |
| bound_region: ty::BoundRegionKind::BrNamed(def_id, _), |
| .. |
| }) = *tcx |
| .map_opaque_lifetime_to_parent_lifetime(param.def_id.expect_local()) |
| { |
| tcx.dcx().emit_err(errors::LifetimeNotCaptured { |
| opaque_span, |
| use_span, |
| param_span: tcx.def_span(def_id), |
| }); |
| } else { |
| // If the `use_span` is actually just the param itself, then we must |
| // have not duplicated the lifetime but captured the original. |
| // The "effective" `use_span` will be the span of the opaque itself, |
| // and the param span will be the def span of the param. |
| tcx.dcx().emit_err(errors::LifetimeNotCaptured { |
| opaque_span, |
| use_span: opaque_span, |
| param_span: use_span, |
| }); |
| } |
| continue; |
| } |
| } |
| ty::GenericParamDefKind::Type { .. } => { |
| if matches!(tcx.def_kind(param.def_id), DefKind::Trait | DefKind::TraitAlias) { |
| // FIXME(precise_capturing): Structured suggestion for this would be useful |
| tcx.dcx().emit_err(errors::SelfTyNotCaptured { |
| trait_span: tcx.def_span(param.def_id), |
| opaque_span: tcx.def_span(opaque_def_id), |
| }); |
| } else { |
| // FIXME(precise_capturing): Structured suggestion for this would be useful |
| tcx.dcx().emit_err(errors::ParamNotCaptured { |
| param_span: tcx.def_span(param.def_id), |
| opaque_span: tcx.def_span(opaque_def_id), |
| kind: "type", |
| }); |
| } |
| } |
| ty::GenericParamDefKind::Const { .. } => { |
| // FIXME(precise_capturing): Structured suggestion for this would be useful |
| tcx.dcx().emit_err(errors::ParamNotCaptured { |
| param_span: tcx.def_span(param.def_id), |
| opaque_span: tcx.def_span(opaque_def_id), |
| kind: "const", |
| }); |
| } |
| } |
| } |
| } |
| } |
| |
| fn is_enum_of_nonnullable_ptr<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| adt_def: AdtDef<'tcx>, |
| args: GenericArgsRef<'tcx>, |
| ) -> bool { |
| if adt_def.repr().inhibit_enum_layout_opt() { |
| return false; |
| } |
| |
| let [var_one, var_two] = &adt_def.variants().raw[..] else { |
| return false; |
| }; |
| let (([], [field]) | ([field], [])) = (&var_one.fields.raw[..], &var_two.fields.raw[..]) else { |
| return false; |
| }; |
| matches!(field.ty(tcx, args).kind(), ty::FnPtr(..) | ty::Ref(..)) |
| } |
| |
| fn check_static_linkage(tcx: TyCtxt<'_>, def_id: LocalDefId) { |
| if tcx.codegen_fn_attrs(def_id).import_linkage.is_some() { |
| if match tcx.type_of(def_id).instantiate_identity().kind() { |
| ty::RawPtr(_, _) => false, |
| ty::Adt(adt_def, args) => !is_enum_of_nonnullable_ptr(tcx, *adt_def, *args), |
| _ => true, |
| } { |
| tcx.dcx().emit_err(errors::LinkageType { span: tcx.def_span(def_id) }); |
| } |
| } |
| } |
| |
| pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) { |
| match tcx.def_kind(def_id) { |
| DefKind::Static { .. } => { |
| tcx.ensure().typeck(def_id); |
| maybe_check_static_with_link_section(tcx, def_id); |
| check_static_inhabited(tcx, def_id); |
| check_static_linkage(tcx, def_id); |
| } |
| DefKind::Const => { |
| tcx.ensure().typeck(def_id); |
| } |
| DefKind::Enum => { |
| check_enum(tcx, def_id); |
| } |
| DefKind::Fn => { |
| if let Some(i) = tcx.intrinsic(def_id) { |
| intrinsic::check_intrinsic_type( |
| tcx, |
| def_id, |
| tcx.def_ident_span(def_id).unwrap(), |
| i.name, |
| Abi::Rust, |
| ) |
| } |
| // Everything else is checked entirely within check_item_body |
| } |
| DefKind::Impl { of_trait } => { |
| if of_trait && let Some(impl_trait_header) = tcx.impl_trait_header(def_id) { |
| if tcx |
| .ensure() |
| .coherent_trait(impl_trait_header.trait_ref.instantiate_identity().def_id) |
| .is_ok() |
| { |
| check_impl_items_against_trait(tcx, def_id, impl_trait_header); |
| check_on_unimplemented(tcx, def_id); |
| } |
| } |
| } |
| DefKind::Trait => { |
| let assoc_items = tcx.associated_items(def_id); |
| check_on_unimplemented(tcx, def_id); |
| |
| for &assoc_item in assoc_items.in_definition_order() { |
| match assoc_item.kind { |
| ty::AssocKind::Fn => { |
| let abi = tcx.fn_sig(assoc_item.def_id).skip_binder().abi(); |
| forbid_intrinsic_abi(tcx, assoc_item.ident(tcx).span, abi); |
| } |
| ty::AssocKind::Type if assoc_item.defaultness(tcx).has_value() => { |
| let trait_args = GenericArgs::identity_for_item(tcx, def_id); |
| let _: Result<_, rustc_errors::ErrorGuaranteed> = check_type_bounds( |
| tcx, |
| assoc_item, |
| assoc_item, |
| ty::TraitRef::new(tcx, def_id.to_def_id(), trait_args), |
| ); |
| } |
| _ => {} |
| } |
| } |
| } |
| DefKind::Struct => { |
| check_struct(tcx, def_id); |
| } |
| DefKind::Union => { |
| check_union(tcx, def_id); |
| } |
| DefKind::OpaqueTy => { |
| check_opaque_precise_captures(tcx, def_id); |
| |
| let origin = tcx.opaque_type_origin(def_id); |
| if let hir::OpaqueTyOrigin::FnReturn(fn_def_id) |
| | hir::OpaqueTyOrigin::AsyncFn(fn_def_id) = origin |
| && let hir::Node::TraitItem(trait_item) = tcx.hir_node_by_def_id(fn_def_id) |
| && let (_, hir::TraitFn::Required(..)) = trait_item.expect_fn() |
| { |
| // Skip opaques from RPIT in traits with no default body. |
| } else { |
| check_opaque(tcx, def_id); |
| } |
| } |
| DefKind::TyAlias => { |
| check_type_alias_type_params_are_used(tcx, def_id); |
| } |
| DefKind::ForeignMod => { |
| let it = tcx.hir().expect_item(def_id); |
| let hir::ItemKind::ForeignMod { abi, items } = it.kind else { |
| return; |
| }; |
| check_abi(tcx, it.hir_id(), it.span, abi); |
| |
| match abi { |
| Abi::RustIntrinsic => { |
| for item in items { |
| intrinsic::check_intrinsic_type( |
| tcx, |
| item.id.owner_id.def_id, |
| item.span, |
| item.ident.name, |
| abi, |
| ); |
| } |
| } |
| |
| _ => { |
| 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.own_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_code_err!( |
| tcx.dcx(), |
| item.span, |
| E0044, |
| "foreign items may not have {kinds} parameters", |
| ) |
| .with_span_label(item.span, format!("can't have {kinds} parameters")) |
| .with_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(fn_decl, _, _) => { |
| require_c_abi_if_c_variadic(tcx, fn_decl, abi, item.span); |
| } |
| hir::ForeignItemKind::Static(..) => { |
| check_static_inhabited(tcx, def_id); |
| check_static_linkage(tcx, def_id); |
| } |
| _ => {} |
| } |
| } |
| } |
| } |
| } |
| DefKind::GlobalAsm => { |
| let it = tcx.hir().expect_item(def_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, def_id); |
| } |
| _ => {} |
| } |
| } |
| |
| pub(super) fn check_on_unimplemented(tcx: TyCtxt<'_>, def_id: LocalDefId) { |
| // an error would be reported if this fails. |
| let _ = OnUnimplementedDirective::of_item(tcx, def_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: DefId, |
| ) { |
| 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.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 { |
| if !tcx.is_impl_trait_in_trait(impl_item) { |
| report_forbidden_specialization(tcx, impl_item, parent_impl); |
| } else { |
| tcx.dcx().delayed_bug(format!("parent item: {parent_impl:?} not marked as default")); |
| } |
| } |
| } |
| |
| fn check_impl_items_against_trait<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| impl_id: LocalDefId, |
| impl_trait_header: ty::ImplTraitHeader<'tcx>, |
| ) { |
| let trait_ref = impl_trait_header.trait_ref.instantiate_identity(); |
| // 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 trait_ref.references_error() { |
| return; |
| } |
| |
| let impl_item_refs = tcx.associated_item_def_ids(impl_id); |
| |
| // Negative impls are not expected to have any items |
| match impl_trait_header.polarity { |
| ty::ImplPolarity::Reservation | ty::ImplPolarity::Positive => {} |
| ty::ImplPolarity::Negative => { |
| if let [first_item_ref, ..] = impl_item_refs { |
| let first_item_span = tcx.def_span(first_item_ref); |
| struct_span_code_err!( |
| tcx.dcx(), |
| first_item_span, |
| E0749, |
| "negative impls cannot have any items" |
| ) |
| .emit(); |
| } |
| return; |
| } |
| } |
| |
| let trait_def = tcx.trait_def(trait_ref.def_id); |
| |
| for &impl_item in impl_item_refs { |
| let ty_impl_item = tcx.associated_item(impl_item); |
| 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.dcx().span_delayed_bug(tcx.def_span(impl_item), "missing associated item in trait"); |
| continue; |
| }; |
| match ty_impl_item.kind { |
| ty::AssocKind::Const => { |
| tcx.ensure().compare_impl_const(( |
| impl_item.expect_local(), |
| ty_impl_item.trait_item_def_id.unwrap(), |
| )); |
| } |
| ty::AssocKind::Fn => { |
| compare_impl_method(tcx, ty_impl_item, ty_trait_item, trait_ref); |
| } |
| ty::AssocKind::Type => { |
| compare_impl_ty(tcx, ty_impl_item, ty_trait_item, trait_ref); |
| } |
| } |
| |
| 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(trait_ref.def_id) { |
| let leaf_def = ancestors.leaf_def(tcx, trait_item_id); |
| |
| let is_implemented = leaf_def |
| .as_ref() |
| .is_some_and(|node_item| node_item.item.defaultness(tcx).has_value()); |
| |
| if !is_implemented && tcx.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 = |
| leaf_def.as_ref().is_some_and(|node_item| !node_item.defining_node.is_from_trait()); |
| |
| if !is_implemented_here { |
| let full_impl_span = tcx.hir().span_with_body(tcx.local_def_id_to_hir_id(impl_id)); |
| 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 let Some(leaf_def) = &leaf_def |
| && !leaf_def.is_final() |
| && let def_id = leaf_def.item.def_id |
| && tcx.impl_method_has_trait_impl_trait_tys(def_id) |
| { |
| let def_kind = tcx.def_kind(def_id); |
| let descr = tcx.def_kind_descr(def_kind, def_id); |
| let (msg, feature) = if tcx.asyncness(def_id).is_async() { |
| ( |
| format!("async {descr} in trait cannot be specialized"), |
| "async functions in traits", |
| ) |
| } else { |
| ( |
| format!( |
| "{descr} with return-position `impl Trait` in trait cannot be specialized" |
| ), |
| "return position `impl Trait` in traits", |
| ) |
| }; |
| tcx.dcx() |
| .struct_span_err(tcx.def_span(def_id), msg) |
| .with_note(format!( |
| "specialization behaves in inconsistent and surprising ways with \ |
| {feature}, and for now is disallowed" |
| )) |
| .emit(); |
| } |
| } |
| |
| if !missing_items.is_empty() { |
| let full_impl_span = tcx.hir().span_with_body(tcx.local_def_id_to_hir_id(impl_id)); |
| missing_items_err(tcx, impl_id, &missing_items, full_impl_span); |
| } |
| |
| if let Some(missing_items) = must_implement_one_of { |
| let attr_span = tcx |
| .get_attr(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).instantiate_identity(); |
| if let ty::Adt(def, args) = t.kind() |
| && def.is_struct() |
| { |
| let fields = &def.non_enum_variant().fields; |
| if fields.is_empty() { |
| struct_span_code_err!(tcx.dcx(), sp, E0075, "SIMD vector cannot be empty").emit(); |
| return; |
| } |
| let e = fields[FieldIdx::ZERO].ty(tcx, args); |
| if !fields.iter().all(|f| f.ty(tcx, args) == e) { |
| struct_span_code_err!(tcx.dcx(), sp, E0076, "SIMD vector should be homogeneous") |
| .with_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_target_usize(tcx, tcx.param_env(def.did())) |
| } else { |
| Some(fields.len() as u64) |
| }; |
| if let Some(len) = len { |
| if len == 0 { |
| struct_span_code_err!(tcx.dcx(), sp, E0075, "SIMD vector cannot be empty").emit(); |
| return; |
| } else if len > MAX_SIMD_LANES { |
| struct_span_code_err!( |
| tcx.dcx(), |
| 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_code_err!( |
| tcx.dcx(), |
| 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 != repr_pack |
| { |
| struct_span_code_err!( |
| tcx.dcx(), |
| sp, |
| E0634, |
| "type has conflicting packed representation hints" |
| ) |
| .emit(); |
| } |
| } |
| } |
| if repr.align.is_some() { |
| struct_span_code_err!( |
| tcx.dcx(), |
| 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_code_err!( |
| tcx.dcx(), |
| 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()).instantiate_identity(), |
| 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, args) = tcx.type_of(def_id).instantiate_identity().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, args).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>, adt: ty::AdtDef<'tcx>) { |
| if !adt.repr().transparent() { |
| return; |
| } |
| |
| if adt.is_union() && !tcx.features().transparent_unions { |
| feature_err( |
| &tcx.sess, |
| sym::transparent_unions, |
| tcx.def_span(adt.did()), |
| "transparent unions are unstable", |
| ) |
| .emit(); |
| } |
| |
| if adt.variants().len() != 1 { |
| bad_variant_count(tcx, adt, tcx.def_span(adt.did()), adt.did()); |
| // Don't bother checking the fields. |
| return; |
| } |
| |
| // For each field, figure out if it's known to have "trivial" layout (i.e., is a 1-ZST), with |
| // "known" respecting #[non_exhaustive] attributes. |
| let field_infos = adt.all_fields().map(|field| { |
| let ty = field.ty(tcx, GenericArgs::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 trivial = layout.is_ok_and(|layout| layout.is_1zst()); |
| if !trivial { |
| return (span, trivial, None); |
| } |
| // Even some 1-ZST fields are not allowed though, if they have `non_exhaustive`. |
| |
| fn check_non_exhaustive<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| t: Ty<'tcx>, |
| ) -> ControlFlow<(&'static str, DefId, GenericArgsRef<'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, args) => { |
| 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(), |
| args, |
| non_exhaustive, |
| )); |
| } |
| } |
| def.all_fields() |
| .map(|field| field.ty(tcx, args)) |
| .try_for_each(|t| check_non_exhaustive(tcx, t)) |
| } |
| _ => ControlFlow::Continue(()), |
| } |
| } |
| |
| (span, trivial, check_non_exhaustive(tcx, ty).break_value()) |
| }); |
| |
| let non_trivial_fields = field_infos |
| .clone() |
| .filter_map(|(span, trivial, _non_exhaustive)| if !trivial { Some(span) } else { None }); |
| let non_trivial_count = non_trivial_fields.clone().count(); |
| if non_trivial_count >= 2 { |
| bad_non_zero_sized_fields( |
| tcx, |
| adt, |
| non_trivial_count, |
| non_trivial_fields, |
| tcx.def_span(adt.did()), |
| ); |
| return; |
| } |
| let mut prev_non_exhaustive_1zst = false; |
| for (span, _trivial, non_exhaustive_1zst) in field_infos { |
| if let Some((descr, def_id, args, non_exhaustive)) = non_exhaustive_1zst { |
| // If there are any non-trivial fields, then there can be no non-exhaustive 1-zsts. |
| // Otherwise, it's only an issue if there's >1 non-exhaustive 1-zst. |
| if non_trivial_count > 0 || prev_non_exhaustive_1zst { |
| tcx.node_span_lint( |
| REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS, |
| tcx.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_args(def_id, args); |
| 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." |
| )); |
| }, |
| ) |
| } else { |
| prev_non_exhaustive_1zst = true; |
| } |
| } |
| } |
| } |
| |
| #[allow(trivial_numeric_casts)] |
| fn check_enum(tcx: TyCtxt<'_>, def_id: LocalDefId) { |
| let def = tcx.adt_def(def_id); |
| def.destructor(tcx); // force the destructor to be evaluated |
| |
| if def.variants().is_empty() { |
| if let Some(attr) = tcx.get_attrs(def_id, sym::repr).next() { |
| struct_span_code_err!( |
| tcx.dcx(), |
| attr.span, |
| E0084, |
| "unsupported representation for zero-variant enum" |
| ) |
| .with_span_label(tcx.def_span(def_id), "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, |
| sym::repr128, |
| tcx.def_span(def_id), |
| "repr with 128-bit type is unstable", |
| ) |
| .emit(); |
| } |
| } |
| |
| for v in def.variants() { |
| if let ty::VariantDiscr::Explicit(discr_def_id) = v.discr { |
| tcx.ensure().typeck(discr_def_id.expect_local()); |
| } |
| } |
| |
| if def.repr().int.is_none() { |
| let is_unit = |var: &ty::VariantDef| matches!(var.ctor_kind(), Some(CtorKind::Const)); |
| let has_disr = |var: &ty::VariantDef| matches!(var.discr, ty::VariantDiscr::Explicit(_)); |
| |
| let has_non_units = def.variants().iter().any(|var| !is_unit(var)); |
| let disr_units = def.variants().iter().any(|var| is_unit(var) && has_disr(var)); |
| let disr_non_unit = def.variants().iter().any(|var| !is_unit(var) && has_disr(var)); |
| |
| if disr_non_unit || (disr_units && has_non_units) { |
| struct_span_code_err!( |
| tcx.dcx(), |
| tcx.def_span(def_id), |
| E0732, |
| "`#[repr(inttype)]` must be specified" |
| ) |
| .emit(); |
| } |
| } |
| |
| detect_discriminant_duplicate(tcx, def); |
| check_transparent(tcx, 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>, adt: ty::AdtDef<'tcx>) { |
| // 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, err: &mut Diag<'_>| { |
| let var = adt.variant(idx); // HIR for the duplicate discriminant |
| let (span, display_discr) = match var.discr { |
| ty::VariantDiscr::Explicit(discr_def_id) => { |
| // In the case the discriminant is both a duplicate and overflowed, let the user know |
| if let hir::Node::AnonConst(expr) = |
| tcx.hir_node_by_def_id(discr_def_id.expect_local()) |
| && 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.def_span(discr_def_id), format!("`{dis}` (overflowed from `{lit_value}`)")) |
| } else { |
| // Otherwise, format the value as-is |
| (tcx.def_span(discr_def_id), format!("`{dis}`")) |
| } |
| } |
| // This should not happen. |
| ty::VariantDiscr::Relative(0) => (tcx.def_span(var.def_id), format!("`{dis}`")), |
| ty::VariantDiscr::Relative(distance_to_explicit) => { |
| // 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(explicit_idx) = |
| idx.as_u32().checked_sub(distance_to_explicit).map(VariantIdx::from_u32) |
| { |
| let explicit_variant = adt.variant(explicit_idx); |
| let ve_ident = var.name; |
| let ex_ident = explicit_variant.name; |
| let sp = if distance_to_explicit > 1 { "variants" } else { "variant" }; |
| |
| err.span_label( |
| tcx.def_span(explicit_variant.def_id), |
| format!( |
| "discriminant for `{ve_ident}` incremented from this startpoint \ |
| (`{ex_ident}` + {distance_to_explicit} {sp} later \ |
| => `{ve_ident}` = {dis})" |
| ), |
| ); |
| } |
| |
| (tcx.def_span(var.def_id), format!("`{dis}`")) |
| } |
| }; |
| |
| err.span_label(span, format!("{display_discr} assigned here")); |
| }; |
| |
| let mut discrs = adt.discriminants(tcx).collect::<Vec<_>>(); |
| |
| // 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 var_i_idx = discrs[i].0; |
| let mut error: Option<Diag<'_, _>> = None; |
| |
| let mut o = i + 1; |
| while o < discrs.len() { |
| let var_o_idx = discrs[o].0; |
| |
| if discrs[i].1.val == discrs[o].1.val { |
| let err = error.get_or_insert_with(|| { |
| let mut ret = struct_span_code_err!( |
| tcx.dcx(), |
| tcx.def_span(adt.did()), |
| E0081, |
| "discriminant value `{}` assigned more than once", |
| discrs[i].1, |
| ); |
| |
| report(discrs[i].1, var_i_idx, &mut ret); |
| |
| ret |
| }); |
| |
| report(discrs[o].1, 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(e) = error { |
| e.emit(); |
| } |
| |
| i += 1; |
| } |
| } |
| |
| fn check_type_alias_type_params_are_used<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) { |
| if tcx.type_alias_is_lazy(def_id) { |
| // Since we compute the variances for lazy type aliases and already reject bivariant |
| // parameters as unused, we can and should skip this check for lazy type aliases. |
| return; |
| } |
| |
| let generics = tcx.generics_of(def_id); |
| if generics.own_counts().types == 0 { |
| return; |
| } |
| |
| let ty = tcx.type_of(def_id).instantiate_identity(); |
| if ty.references_error() { |
| // If there is already another error, do not emit an error for not using a type parameter. |
| assert!(tcx.dcx().has_errors().is_some()); |
| return; |
| } |
| |
| // Lazily calculated because it is only needed in case of an error. |
| let bounded_params = LazyCell::new(|| { |
| tcx.explicit_predicates_of(def_id) |
| .predicates |
| .iter() |
| .filter_map(|(predicate, span)| { |
| let bounded_ty = match predicate.kind().skip_binder() { |
| ty::ClauseKind::Trait(pred) => pred.trait_ref.self_ty(), |
| ty::ClauseKind::TypeOutlives(pred) => pred.0, |
| _ => return None, |
| }; |
| if let ty::Param(param) = bounded_ty.kind() { |
| Some((param.index, span)) |
| } else { |
| None |
| } |
| }) |
| // FIXME: This assumes that elaborated `Sized` bounds come first (which does hold at the |
| // time of writing). This is a bit fragile since we later use the span to detect elaborated |
| // `Sized` bounds. If they came last for example, this would break `Trait + /*elab*/Sized` |
| // since it would overwrite the span of the user-written bound. This could be fixed by |
| // folding the spans with `Span::to` which requires a bit of effort I think. |
| .collect::<FxIndexMap<_, _>>() |
| }); |
| |
| let mut params_used = BitSet::new_empty(generics.own_params.len()); |
| 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.own_params { |
| if !params_used.contains(param.index) |
| && let ty::GenericParamDefKind::Type { .. } = param.kind |
| { |
| let span = tcx.def_span(param.def_id); |
| let param_name = Ident::new(param.name, span); |
| |
| // The corresponding predicates are post-`Sized`-elaboration. Therefore we |
| // * check for emptiness to detect lone user-written `?Sized` bounds |
| // * compare the param span to the pred span to detect lone user-written `Sized` bounds |
| let has_explicit_bounds = bounded_params.is_empty() |
| || (*bounded_params).get(¶m.index).is_some_and(|&&pred_sp| pred_sp != span); |
| let const_param_help = (!has_explicit_bounds).then_some(()); |
| |
| let mut diag = tcx.dcx().create_err(errors::UnusedGenericParameter { |
| span, |
| param_name, |
| param_def_kind: tcx.def_descr(param.def_id), |
| help: errors::UnusedGenericParameterHelp::TyAlias { param_name }, |
| const_param_help, |
| }); |
| diag.code(E0091); |
| diag.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<'_>, |
| opaque_def_id: LocalDefId, |
| span: Span, |
| ) -> ErrorGuaranteed { |
| let mut err = struct_span_code_err!(tcx.dcx(), span, E0720, "cannot resolve opaque type"); |
| |
| let mut label = false; |
| if let Some((def_id, visitor)) = get_owner_return_paths(tcx, opaque_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)) |
| { |
| #[derive(Default)] |
| struct OpaqueTypeCollector { |
| opaques: Vec<DefId>, |
| closures: Vec<DefId>, |
| } |
| impl<'tcx> ty::visit::TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector { |
| fn visit_ty(&mut self, t: Ty<'tcx>) { |
| match *t.kind() { |
| ty::Alias(ty::Opaque, ty::AliasTy { def_id: def, .. }) => { |
| self.opaques.push(def); |
| } |
| ty::Closure(def_id, ..) | ty::Coroutine(def_id, ..) => { |
| self.closures.push(def_id); |
| t.super_visit_with(self); |
| } |
| _ => t.super_visit_with(self), |
| } |
| } |
| } |
| |
| let mut visitor = OpaqueTypeCollector::default(); |
| ty.visit_with(&mut visitor); |
| for def_id in visitor.opaques { |
| let ty_span = tcx.def_span(def_id); |
| if !seen.contains(&ty_span) { |
| let descr = if ty.is_impl_trait() { "opaque " } else { "" }; |
| err.span_label(ty_span, format!("returning this {descr}type `{ty}`")); |
| seen.insert(ty_span); |
| } |
| err.span_label(sp, format!("returning here with type `{ty}`")); |
| } |
| |
| for closure_def_id in visitor.closures { |
| let Some(closure_local_did) = closure_def_id.as_local() else { |
| continue; |
| }; |
| let typeck_results = tcx.typeck(closure_local_did); |
| |
| let mut label_match = |ty: Ty<'_>, span| { |
| for arg in ty.walk() { |
| if let ty::GenericArgKind::Type(ty) = arg.unpack() |
| && let ty::Alias( |
| ty::Opaque, |
| ty::AliasTy { def_id: captured_def_id, .. }, |
| ) = *ty.kind() |
| && captured_def_id == opaque_def_id.to_def_id() |
| { |
| err.span_label( |
| span, |
| format!( |
| "{} captures itself here", |
| tcx.def_descr(closure_def_id) |
| ), |
| ); |
| } |
| } |
| }; |
| |
| // Label any closure upvars that capture the opaque |
| for capture in typeck_results.closure_min_captures_flattened(closure_local_did) |
| { |
| label_match(capture.place.ty(), capture.get_path_span(tcx)); |
| } |
| // Label any coroutine locals that capture the opaque |
| if tcx.is_coroutine(closure_def_id) |
| && let Some(coroutine_layout) = tcx.mir_coroutine_witnesses(closure_def_id) |
| { |
| for interior_ty in &coroutine_layout.field_tys { |
| label_match(interior_ty.ty, interior_ty.source_info.span); |
| } |
| } |
| } |
| } |
| } |
| } |
| if !label { |
| err.span_label(span, "cannot resolve opaque type"); |
| } |
| err.emit() |
| } |
| |
| pub(super) fn check_coroutine_obligations( |
| tcx: TyCtxt<'_>, |
| def_id: LocalDefId, |
| ) -> Result<(), ErrorGuaranteed> { |
| debug_assert!(!tcx.is_typeck_child(def_id.to_def_id())); |
| |
| let typeck_results = tcx.typeck(def_id); |
| let param_env = tcx.param_env(def_id); |
| |
| debug!(?typeck_results.coroutine_stalled_predicates); |
| |
| let infcx = tcx |
| .infer_ctxt() |
| // typeck writeback gives us predicates with their regions erased. |
| // As borrowck already has checked lifetimes, we do not need to do it again. |
| .ignoring_regions() |
| .with_opaque_type_inference(def_id) |
| .build(); |
| |
| let ocx = ObligationCtxt::new(&infcx); |
| for (predicate, cause) in &typeck_results.coroutine_stalled_predicates { |
| ocx.register_obligation(Obligation::new(tcx, cause.clone(), param_env, *predicate)); |
| } |
| |
| let errors = ocx.select_all_or_error(); |
| debug!(?errors); |
| if !errors.is_empty() { |
| return Err(infcx.err_ctxt().report_fulfillment_errors(errors)); |
| } |
| |
| // Check that any hidden types found when checking these stalled coroutine obligations |
| // are valid. |
| for (key, ty) in infcx.take_opaque_types() { |
| let hidden_type = infcx.resolve_vars_if_possible(ty.hidden_type); |
| let key = infcx.resolve_vars_if_possible(key); |
| sanity_check_found_hidden_type(tcx, key, hidden_type)?; |
| } |
| |
| Ok(()) |
| } |
