From cf94bdc0742c13e2a0cac864c478b8626b266e1b Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:11:38 +0200 Subject: Merging upstream version 1.66.0+dfsg1. Signed-off-by: Daniel Baumann --- compiler/rustc_typeck/src/check/check.rs | 1753 ------------------------------ 1 file changed, 1753 deletions(-) delete mode 100644 compiler/rustc_typeck/src/check/check.rs (limited to 'compiler/rustc_typeck/src/check/check.rs') diff --git a/compiler/rustc_typeck/src/check/check.rs b/compiler/rustc_typeck/src/check/check.rs deleted file mode 100644 index d6fa74c87..000000000 --- a/compiler/rustc_typeck/src/check/check.rs +++ /dev/null @@ -1,1753 +0,0 @@ -use crate::check::intrinsicck::InlineAsmCtxt; - -use super::coercion::CoerceMany; -use super::compare_method::check_type_bounds; -use super::compare_method::{compare_const_impl, 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::lang_items::LangItem; -use rustc_hir::{ItemKind, Node, PathSegment}; -use rustc_infer::infer::outlives::env::OutlivesEnvironment; -use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; -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::InferCtxtExt as _; -use rustc_trait_selection::traits::{self, ObligationCtxt}; -use rustc_ty_utils::representability::{self, Representability}; - -use std::ops::ControlFlow; - -pub(super) 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, |lint| { - lint.build("use of calling convention not supported on this target").emit(); - }); - } - } - - // 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(); - } -} - -/// Helper used for fns and closures. Does the grungy work of checking a function -/// body and returns the function context used for that purpose, since in the case of a fn item -/// there is still a bit more to do. -/// -/// * ... -/// * inherited: other fields inherited from the enclosing fn (if any) -#[instrument(skip(inherited, body), level = "debug")] -pub(super) fn check_fn<'a, 'tcx>( - inherited: &'a Inherited<'a, 'tcx>, - param_env: ty::ParamEnv<'tcx>, - fn_sig: ty::FnSig<'tcx>, - decl: &'tcx hir::FnDecl<'tcx>, - fn_id: hir::HirId, - body: &'tcx hir::Body<'tcx>, - can_be_generator: Option, - return_type_pre_known: bool, -) -> (FnCtxt<'a, 'tcx>, Option>) { - // Create the function context. This is either derived from scratch or, - // in the case of closures, based on the outer context. - let mut fcx = FnCtxt::new(inherited, param_env, body.value.hir_id); - fcx.ps.set(UnsafetyState::function(fn_sig.unsafety, fn_id)); - fcx.return_type_pre_known = return_type_pre_known; - - let tcx = fcx.tcx; - let hir = tcx.hir(); - - let declared_ret_ty = fn_sig.output(); - - let ret_ty = - fcx.register_infer_ok_obligations(fcx.infcx.replace_opaque_types_with_inference_vars( - declared_ret_ty, - body.value.hir_id, - decl.output.span(), - param_env, - )); - // If we replaced declared_ret_ty with infer vars, then we must be inferring - // an opaque type, so set a flag so we can improve diagnostics. - fcx.return_type_has_opaque = ret_ty != declared_ret_ty; - - fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(ret_ty))); - - let span = body.value.span; - - fn_maybe_err(tcx, span, fn_sig.abi); - - if fn_sig.abi == Abi::RustCall { - let expected_args = if let ImplicitSelfKind::None = decl.implicit_self { 1 } else { 2 }; - - let err = || { - let item = match tcx.hir().get(fn_id) { - Node::Item(hir::Item { kind: ItemKind::Fn(header, ..), .. }) => Some(header), - Node::ImplItem(hir::ImplItem { - kind: hir::ImplItemKind::Fn(header, ..), .. - }) => Some(header), - Node::TraitItem(hir::TraitItem { - kind: hir::TraitItemKind::Fn(header, ..), - .. - }) => Some(header), - // Closures are RustCall, but they tuple their arguments, so shouldn't be checked - Node::Expr(hir::Expr { kind: hir::ExprKind::Closure { .. }, .. }) => None, - node => bug!("Item being checked wasn't a function/closure: {:?}", node), - }; - - if let Some(header) = item { - tcx.sess.span_err(header.span, "functions with the \"rust-call\" ABI must take a single non-self argument that is a tuple"); - } - }; - - if fn_sig.inputs().len() != expected_args { - err() - } else { - // FIXME(CraftSpider) Add a check on parameter expansion, so we don't just make the ICE happen later on - // This will probably require wide-scale changes to support a TupleKind obligation - // We can't resolve this without knowing the type of the param - if !matches!(fn_sig.inputs()[expected_args - 1].kind(), ty::Tuple(_) | ty::Param(_)) { - err() - } - } - } - - if body.generator_kind.is_some() && can_be_generator.is_some() { - let yield_ty = fcx - .next_ty_var(TypeVariableOrigin { kind: TypeVariableOriginKind::TypeInference, span }); - fcx.require_type_is_sized(yield_ty, span, traits::SizedYieldType); - - // Resume type defaults to `()` if the generator has no argument. - let resume_ty = fn_sig.inputs().get(0).copied().unwrap_or_else(|| tcx.mk_unit()); - - fcx.resume_yield_tys = Some((resume_ty, yield_ty)); - } - - GatherLocalsVisitor::new(&fcx).visit_body(body); - - // C-variadic fns also have a `VaList` input that's not listed in `fn_sig` - // (as it's created inside the body itself, not passed in from outside). - let maybe_va_list = if fn_sig.c_variadic { - let span = body.params.last().unwrap().span; - let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(span)); - let region = fcx.next_region_var(RegionVariableOrigin::MiscVariable(span)); - - Some(tcx.bound_type_of(va_list_did).subst(tcx, &[region.into()])) - } else { - None - }; - - // Add formal parameters. - let inputs_hir = hir.fn_decl_by_hir_id(fn_id).map(|decl| &decl.inputs); - let inputs_fn = fn_sig.inputs().iter().copied(); - for (idx, (param_ty, param)) in inputs_fn.chain(maybe_va_list).zip(body.params).enumerate() { - // Check the pattern. - let ty_span = try { inputs_hir?.get(idx)?.span }; - fcx.check_pat_top(¶m.pat, param_ty, ty_span, false); - - // Check that argument is Sized. - // The check for a non-trivial pattern is a hack to avoid duplicate warnings - // for simple cases like `fn foo(x: Trait)`, - // where we would error once on the parameter as a whole, and once on the binding `x`. - if param.pat.simple_ident().is_none() && !tcx.features().unsized_fn_params { - fcx.require_type_is_sized(param_ty, param.pat.span, traits::SizedArgumentType(ty_span)); - } - - fcx.write_ty(param.hir_id, param_ty); - } - - inherited.typeck_results.borrow_mut().liberated_fn_sigs_mut().insert(fn_id, fn_sig); - - fcx.in_tail_expr = true; - if let ty::Dynamic(..) = declared_ret_ty.kind() { - // FIXME: We need to verify that the return type is `Sized` after the return expression has - // been evaluated so that we have types available for all the nodes being returned, but that - // requires the coerced evaluated type to be stored. Moving `check_return_expr` before this - // causes unsized errors caused by the `declared_ret_ty` to point at the return expression, - // while keeping the current ordering we will ignore the tail expression's type because we - // don't know it yet. We can't do `check_expr_kind` while keeping `check_return_expr` - // because we will trigger "unreachable expression" lints unconditionally. - // Because of all of this, we perform a crude check to know whether the simplest `!Sized` - // case that a newcomer might make, returning a bare trait, and in that case we populate - // the tail expression's type so that the suggestion will be correct, but ignore all other - // possible cases. - fcx.check_expr(&body.value); - fcx.require_type_is_sized(declared_ret_ty, decl.output.span(), traits::SizedReturnType); - } else { - fcx.require_type_is_sized(declared_ret_ty, decl.output.span(), traits::SizedReturnType); - fcx.check_return_expr(&body.value, false); - } - fcx.in_tail_expr = false; - - // We insert the deferred_generator_interiors entry after visiting the body. - // This ensures that all nested generators appear before the entry of this generator. - // resolve_generator_interiors relies on this property. - let gen_ty = if let (Some(_), Some(gen_kind)) = (can_be_generator, body.generator_kind) { - let interior = fcx - .next_ty_var(TypeVariableOrigin { kind: TypeVariableOriginKind::MiscVariable, span }); - fcx.deferred_generator_interiors.borrow_mut().push((body.id(), interior, gen_kind)); - - let (resume_ty, yield_ty) = fcx.resume_yield_tys.unwrap(); - Some(GeneratorTypes { - resume_ty, - yield_ty, - interior, - movability: can_be_generator.unwrap(), - }) - } else { - None - }; - - // Finalize the return check by taking the LUB of the return types - // we saw and assigning it to the expected return type. This isn't - // really expected to fail, since the coercions would have failed - // earlier when trying to find a LUB. - let coercion = fcx.ret_coercion.take().unwrap().into_inner(); - let mut actual_return_ty = coercion.complete(&fcx); - debug!("actual_return_ty = {:?}", actual_return_ty); - if let ty::Dynamic(..) = declared_ret_ty.kind() { - // We have special-cased the case where the function is declared - // `-> dyn Foo` and we don't actually relate it to the - // `fcx.ret_coercion`, so just substitute a type variable. - actual_return_ty = - fcx.next_ty_var(TypeVariableOrigin { kind: TypeVariableOriginKind::DynReturnFn, span }); - debug!("actual_return_ty replaced with {:?}", actual_return_ty); - } - - // HACK(oli-obk, compiler-errors): We should be comparing this against - // `declared_ret_ty`, but then anything uninferred would be inferred to - // the opaque type itself. That again would cause writeback to assume - // we have a recursive call site and do the sadly stabilized fallback to `()`. - fcx.demand_suptype(span, ret_ty, actual_return_ty); - - // Check that a function marked as `#[panic_handler]` has signature `fn(&PanicInfo) -> !` - if let Some(panic_impl_did) = tcx.lang_items().panic_impl() - && panic_impl_did == hir.local_def_id(fn_id).to_def_id() - { - check_panic_info_fn(tcx, panic_impl_did.expect_local(), fn_sig, decl, declared_ret_ty); - } - - // Check that a function marked as `#[alloc_error_handler]` has signature `fn(Layout) -> !` - if let Some(alloc_error_handler_did) = tcx.lang_items().oom() - && alloc_error_handler_did == hir.local_def_id(fn_id).to_def_id() - { - check_alloc_error_fn(tcx, alloc_error_handler_did.expect_local(), fn_sig, decl, declared_ret_ty); - } - - (fcx, gen_ty) -} - -fn check_panic_info_fn( - tcx: TyCtxt<'_>, - fn_id: LocalDefId, - fn_sig: ty::FnSig<'_>, - decl: &hir::FnDecl<'_>, - declared_ret_ty: Ty<'_>, -) { - let Some(panic_info_did) = tcx.lang_items().panic_info() else { - tcx.sess.err("language item required, but not found: `panic_info`"); - return; - }; - - if *declared_ret_ty.kind() != ty::Never { - tcx.sess.span_err(decl.output.span(), "return type should be `!`"); - } - - let inputs = fn_sig.inputs(); - if inputs.len() != 1 { - tcx.sess.span_err(tcx.def_span(fn_id), "function should have one argument"); - return; - } - - let arg_is_panic_info = match *inputs[0].kind() { - ty::Ref(region, ty, mutbl) => match *ty.kind() { - ty::Adt(ref adt, _) => { - adt.did() == panic_info_did && mutbl == hir::Mutability::Not && !region.is_static() - } - _ => false, - }, - _ => false, - }; - - if !arg_is_panic_info { - tcx.sess.span_err(decl.inputs[0].span, "argument should be `&PanicInfo`"); - } - - let DefKind::Fn = tcx.def_kind(fn_id) else { - let span = tcx.def_span(fn_id); - tcx.sess.span_err(span, "should be a function"); - return; - }; - - let generic_counts = tcx.generics_of(fn_id).own_counts(); - if generic_counts.types != 0 { - let span = tcx.def_span(fn_id); - tcx.sess.span_err(span, "should have no type parameters"); - } - if generic_counts.consts != 0 { - let span = tcx.def_span(fn_id); - tcx.sess.span_err(span, "should have no const parameters"); - } -} - -fn check_alloc_error_fn( - tcx: TyCtxt<'_>, - fn_id: LocalDefId, - fn_sig: ty::FnSig<'_>, - decl: &hir::FnDecl<'_>, - declared_ret_ty: Ty<'_>, -) { - let Some(alloc_layout_did) = tcx.lang_items().alloc_layout() else { - tcx.sess.err("language item required, but not found: `alloc_layout`"); - return; - }; - - if *declared_ret_ty.kind() != ty::Never { - tcx.sess.span_err(decl.output.span(), "return type should be `!`"); - } - - let inputs = fn_sig.inputs(); - if inputs.len() != 1 { - tcx.sess.span_err(tcx.def_span(fn_id), "function should have one argument"); - return; - } - - let arg_is_alloc_layout = match inputs[0].kind() { - ty::Adt(ref adt, _) => adt.did() == alloc_layout_did, - _ => false, - }; - - if !arg_is_alloc_layout { - tcx.sess.span_err(decl.inputs[0].span, "argument should be `Layout`"); - } - - let DefKind::Fn = tcx.def_kind(fn_id) else { - let span = tcx.def_span(fn_id); - tcx.sess.span_err(span, "`#[alloc_error_handler]` should be a function"); - return; - }; - - let generic_counts = tcx.generics_of(fn_id).own_counts(); - if generic_counts.types != 0 { - let span = tcx.def_span(fn_id); - tcx.sess.span_err(span, "`#[alloc_error_handler]` function should have no type parameters"); - } - if generic_counts.consts != 0 { - let span = tcx.def_span(fn_id); - tcx.sess - .span_err(span, "`#[alloc_error_handler]` function should have no const parameters"); - } -} - -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 - check_representable(tcx, span, def_id); - - 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_representable(tcx, span, def_id); - 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.at(span), 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, - |lint| { - lint.build("static of uninhabited type") - .note("uninhabited statics cannot be initialized, and any access would be an immediate error") - .emit(); - }, - ); - } -} - -/// Checks that an opaque type does not contain cycles and does not use `Self` or `T::Foo` -/// projections that would result in "inheriting lifetimes". -pub(super) fn check_opaque<'tcx>( - tcx: TyCtxt<'tcx>, - def_id: LocalDefId, - substs: SubstsRef<'tcx>, - origin: &hir::OpaqueTyOrigin, -) { - let span = tcx.def_span(def_id); - check_opaque_for_inheriting_lifetimes(tcx, def_id, span); - if tcx.type_of(def_id).references_error() { - return; - } - if check_opaque_for_cycles(tcx, def_id, substs, span, origin).is_err() { - return; - } - check_opaque_meets_bounds(tcx, 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 { - 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 { - 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)>, - } - - impl<'tcx> ty::visit::TypeVisitor<'tcx> for ProhibitOpaqueVisitor<'tcx> { - type BreakTy = Ty<'tcx>; - - fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow { - 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::SelfTy { trait_: _, alias_to: impl_ref }, .. }] => { - let impl_ty_name = - impl_ref.map(|(def_id, _)| 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: -/// -/// type X = impl Clone -/// fn f(t: T) -> X { -/// t -/// } -/// -/// Without this check the above code is incorrectly accepted: we would ICE if -/// some tried, for example, to clone an `Option>`. -#[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 hidden_type = tcx.bound_type_of(def_id.to_def_id()).subst(tcx, substs); - - 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); - - tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::Bind(defining_use_anchor)).enter( - move |infcx| { - let ocx = ObligationCtxt::new(&infcx); - let opaque_ty = tcx.mk_opaque(def_id.to_def_id(), substs); - - let misc_cause = traits::ObligationCause::misc(span, hir_id); - - match infcx.at(&misc_cause, param_env).eq(opaque_ty, hidden_type) { - Ok(infer_ok) => ocx.register_infer_ok_obligations(infer_ok), - Err(ty_err) => { - tcx.sess.delay_span_bug( - span, - &format!("could not unify `{hidden_type}` 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_type.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.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.def_id, - tcx.def_path_str(id.def_id.to_def_id()) - ); - let _indenter = indenter(); - match tcx.def_kind(id.def_id) { - DefKind::Static(..) => { - tcx.ensure().typeck(id.def_id); - maybe_check_static_with_link_section(tcx, id.def_id); - check_static_inhabited(tcx, id.def_id); - } - DefKind::Const => { - tcx.ensure().typeck(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.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.def_id); - if let Some(impl_trait_ref) = tcx.impl_trait_ref(it.def_id) { - check_impl_items_against_trait( - tcx, - it.span, - it.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.def_id); - let trait_substs = - InternalSubsts::identity_for_item(tcx, it.def_id.to_def_id()); - let _: Result<_, rustc_errors::ErrorGuaranteed> = check_type_bounds( - tcx, - assoc_item, - assoc_item, - default.span, - ty::TraitRef { def_id: it.def_id.to_def_id(), substs: trait_substs }, - ); - } - _ => {} - } - } - } - DefKind::Struct => { - check_struct(tcx, id.def_id); - } - DefKind::Union => { - check_union(tcx, id.def_id); - } - DefKind::OpaqueTy => { - let item = tcx.hir().item(id); - let hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) = item.kind else { - 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 { - let substs = InternalSubsts::identity_for_item(tcx, item.def_id.to_def_id()); - check_opaque(tcx, item.def_id, substs, &origin); - } - } - DefKind::TyAlias => { - let pty_ty = tcx.type_of(id.def_id); - let generics = tcx.generics_of(id.def_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.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.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: &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.def_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(..) => { - // Find associated const definition. - compare_const_impl( - tcx, - &ty_impl_item, - impl_item.span, - &ty_trait_item, - impl_trait_ref, - ); - } - 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::TyAlias(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, - ); - } - } -} - -/// Checks whether a type can be represented in memory. In particular, it -/// identifies types that contain themselves without indirection through a -/// pointer, which would mean their size is unbounded. -pub(super) fn check_representable(tcx: TyCtxt<'_>, sp: Span, item_def_id: LocalDefId) -> bool { - let rty = tcx.type_of(item_def_id); - - // Check that it is possible to represent this type. This call identifies - // (1) types that contain themselves and (2) types that contain a different - // recursive type. It is only necessary to throw an error on those that - // contain themselves. For case 2, there must be an inner type that will be - // caught by case 1. - match representability::ty_is_representable(tcx, rty, sp, None) { - Representability::SelfRecursive(spans) => { - recursive_type_with_infinite_size_error(tcx, item_def_id.to_def_id(), spans); - return false; - } - Representability::Representable | Representability::ContainsRecursive => (), - } - true -} - -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) 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; 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, -) -> Option> { - 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, - |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.build("zero-sized fields in repr(transparent) cannot contain external non-exhaustive types") - .note(format!("this {descr} contains `{field_ty}`, which {note}, \ - and makes it not a breaking change to become non-zero-sized in the future.")) - .emit(); - }, - ) - } - } -} - -#[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() && tcx.features().arbitrary_enum_discriminant { - 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_representable(tcx, sp, def_id); - 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> = 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::>(); - 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); - impl<'tcx> ty::visit::TypeVisitor<'tcx> for OpaqueTypeCollector { - fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow { - 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() -} -- cgit v1.2.3