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-rw-r--r--compiler/rustc_typeck/src/check/check.rs1712
1 files changed, 0 insertions, 1712 deletions
diff --git a/compiler/rustc_typeck/src/check/check.rs b/compiler/rustc_typeck/src/check/check.rs
deleted file mode 100644
index 9c1fd9b30..000000000
--- a/compiler/rustc_typeck/src/check/check.rs
+++ /dev/null
@@ -1,1712 +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::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::iter;
-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<hir::Movability>,
- return_type_pre_known: bool,
-) -> (FnCtxt<'a, 'tcx>, Option<GeneratorTypes<'tcx>>) {
- // 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 infering
- // 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)));
- fcx.ret_type_span = Some(decl.output.span());
-
- 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(&param.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<Self::BreakTy> {
- debug!("FindParentLifetimeVisitor: r={:?}", r);
- if let ty::ReEarlyBound(ty::EarlyBoundRegion { index, .. }) = *r {
- if index < self.0.parent_count as u32 {
- return ControlFlow::Break(FoundParentLifetime);
- } else {
- return ControlFlow::CONTINUE;
- }
- }
-
- r.super_visit_with(self)
- }
-
- fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
- if let ty::ConstKind::Unevaluated(..) = c.kind() {
- // FIXME(#72219) We currently don't detect lifetimes within substs
- // which would violate this check. Even though the particular substitution is not used
- // within the const, this should still be fixed.
- return ControlFlow::CONTINUE;
- }
- c.super_visit_with(self)
- }
- }
-
- struct ProhibitOpaqueVisitor<'tcx> {
- tcx: TyCtxt<'tcx>,
- opaque_identity_ty: Ty<'tcx>,
- generics: &'tcx ty::Generics,
- selftys: Vec<(Span, Option<String>)>,
- }
-
- impl<'tcx> ty::visit::TypeVisitor<'tcx> for ProhibitOpaqueVisitor<'tcx> {
- type BreakTy = Ty<'tcx>;
-
- fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
- debug!("check_opaque_for_inheriting_lifetimes: (visit_ty) t={:?}", t);
- if t == self.opaque_identity_ty {
- ControlFlow::CONTINUE
- } else {
- t.super_visit_with(&mut FindParentLifetimeVisitor(self.generics))
- .map_break(|FoundParentLifetime| t)
- }
- }
- }
-
- impl<'tcx> Visitor<'tcx> for ProhibitOpaqueVisitor<'tcx> {
- type NestedFilter = nested_filter::OnlyBodies;
-
- fn nested_visit_map(&mut self) -> Self::Map {
- self.tcx.hir()
- }
-
- fn visit_ty(&mut self, arg: &'tcx hir::Ty<'tcx>) {
- match arg.kind {
- hir::TyKind::Path(hir::QPath::Resolved(None, path)) => match &path.segments {
- [
- PathSegment {
- res: Some(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<T> = impl Clone
-/// fn f<T: Clone>(t: T) -> X<T> {
-/// t
-/// }
-///
-/// Without this check the above code is incorrectly accepted: we would ICE if
-/// some tried, for example, to clone an `Option<X<&mut ()>>`.
-#[instrument(level = "debug", skip(tcx))]
-fn check_opaque_meets_bounds<'tcx>(
- tcx: TyCtxt<'tcx>,
- def_id: LocalDefId,
- substs: SubstsRef<'tcx>,
- span: Span,
- origin: &hir::OpaqueTyOrigin,
-) {
- let 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));
- }
-
- if let Some(required_items) = &must_implement_one_of {
- // 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 {
- 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, T) through, let monomorphization catch errors
- ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::RawPtr(_) => (), // struct(u8, u8, u8, u8) is ok
- ty::Array(t, _) if matches!(t.kind(), ty::Param(_)) => (), // pass struct<T>([T; N]) through, let monomorphization catch errors
- ty::Array(t, _clen)
- if matches!(
- t.kind(),
- ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::RawPtr(_)
- ) =>
- { /* struct([f32; 4]) is ok */ }
- _ => {
- struct_span_err!(
- tcx.sess,
- sp,
- E0077,
- "SIMD vector element type should be a \
- primitive scalar (integer/float/pointer) type"
- )
- .emit();
- return;
- }
- }
- }
-}
-
-pub(super) fn check_packed(tcx: TyCtxt<'_>, sp: Span, def: ty::AdtDef<'_>) {
- let repr = def.repr();
- if repr.packed() {
- for attr in tcx.get_attrs(def.did(), sym::repr) {
- for r in attr::parse_repr_attr(&tcx.sess, attr) {
- if let attr::ReprPacked(pack) = r
- && let Some(repr_pack) = repr.pack
- && pack as u64 != repr_pack.bytes()
- {
- struct_span_err!(
- tcx.sess,
- sp,
- E0634,
- "type has conflicting packed representation hints"
- )
- .emit();
- }
- }
- }
- if repr.align.is_some() {
- struct_span_err!(
- tcx.sess,
- sp,
- E0587,
- "type has conflicting packed and align representation hints"
- )
- .emit();
- } else {
- if let Some(def_spans) = check_packed_inner(tcx, def.did(), &mut vec![]) {
- let mut err = struct_span_err!(
- tcx.sess,
- sp,
- E0588,
- "packed type cannot transitively contain a `#[repr(align)]` type"
- );
-
- err.span_note(
- tcx.def_span(def_spans[0].0),
- &format!(
- "`{}` has a `#[repr(align)]` attribute",
- tcx.item_name(def_spans[0].0)
- ),
- );
-
- if def_spans.len() > 2 {
- let mut first = true;
- for (adt_def, span) in def_spans.iter().skip(1).rev() {
- let ident = tcx.item_name(*adt_def);
- err.span_note(
- *span,
- &if first {
- format!(
- "`{}` contains a field of type `{}`",
- tcx.type_of(def.did()),
- ident
- )
- } else {
- format!("...which contains a field of type `{ident}`")
- },
- );
- first = false;
- }
- }
-
- err.emit();
- }
- }
- }
-}
-
-pub(super) fn check_packed_inner(
- tcx: TyCtxt<'_>,
- def_id: DefId,
- stack: &mut Vec<DefId>,
-) -> Option<Vec<(DefId, Span)>> {
- if let ty::Adt(def, substs) = tcx.type_of(def_id).kind() {
- if def.is_struct() || def.is_union() {
- if def.repr().align.is_some() {
- return Some(vec![(def.did(), DUMMY_SP)]);
- }
-
- stack.push(def_id);
- for field in &def.non_enum_variant().fields {
- if let ty::Adt(def, _) = field.ty(tcx, substs).kind()
- && !stack.contains(&def.did())
- && let Some(mut defs) = check_packed_inner(tcx, def.did(), stack)
- {
- defs.push((def.did(), field.ident(tcx).span));
- return Some(defs);
- }
- }
- stack.pop();
- }
- }
-
- None
-}
-
-pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, adt: ty::AdtDef<'tcx>) {
- if !adt.repr().transparent() {
- return;
- }
-
- if adt.is_union() && !tcx.features().transparent_unions {
- feature_err(
- &tcx.sess.parse_sess,
- sym::transparent_unions,
- sp,
- "transparent unions are unstable",
- )
- .emit();
- }
-
- if adt.variants().len() != 1 {
- bad_variant_count(tcx, adt, sp, adt.did());
- if adt.variants().is_empty() {
- // Don't bother checking the fields. No variants (and thus no fields) exist.
- return;
- }
- }
-
- // For each field, figure out if it's known to be a ZST and align(1), with "known"
- // respecting #[non_exhaustive] attributes.
- let field_infos = adt.all_fields().map(|field| {
- let ty = field.ty(tcx, InternalSubsts::identity_for_item(tcx, field.did));
- let param_env = tcx.param_env(field.did);
- let layout = tcx.layout_of(param_env.and(ty));
- // We are currently checking the type this field came from, so it must be local
- let span = tcx.hir().span_if_local(field.did).unwrap();
- let zst = layout.map_or(false, |layout| layout.is_zst());
- let align1 = layout.map_or(false, |layout| layout.align.abi.bytes() == 1);
- if !zst {
- return (span, zst, align1, None);
- }
-
- fn check_non_exhaustive<'tcx>(
- tcx: TyCtxt<'tcx>,
- t: Ty<'tcx>,
- ) -> ControlFlow<(&'static str, DefId, SubstsRef<'tcx>, bool)> {
- match t.kind() {
- ty::Tuple(list) => list.iter().try_for_each(|t| check_non_exhaustive(tcx, t)),
- ty::Array(ty, _) => check_non_exhaustive(tcx, *ty),
- ty::Adt(def, subst) => {
- if !def.did().is_local() {
- let non_exhaustive = def.is_variant_list_non_exhaustive()
- || def
- .variants()
- .iter()
- .any(ty::VariantDef::is_field_list_non_exhaustive);
- let has_priv = def.all_fields().any(|f| !f.vis.is_public());
- if non_exhaustive || has_priv {
- return ControlFlow::Break((
- def.descr(),
- def.did(),
- subst,
- non_exhaustive,
- ));
- }
- }
- def.all_fields()
- .map(|field| field.ty(tcx, subst))
- .try_for_each(|t| check_non_exhaustive(tcx, t))
- }
- _ => ControlFlow::Continue(()),
- }
- }
-
- (span, zst, align1, check_non_exhaustive(tcx, ty).break_value())
- });
-
- let non_zst_fields = field_infos
- .clone()
- .filter_map(|(span, zst, _align1, _non_exhaustive)| if !zst { Some(span) } else { None });
- let non_zst_count = non_zst_fields.clone().count();
- if non_zst_count >= 2 {
- bad_non_zero_sized_fields(tcx, adt, non_zst_count, non_zst_fields, sp);
- }
- let incompatible_zst_fields =
- field_infos.clone().filter(|(_, _, _, opt)| opt.is_some()).count();
- let incompat = incompatible_zst_fields + non_zst_count >= 2 && non_zst_count < 2;
- for (span, zst, align1, non_exhaustive) in field_infos {
- if zst && !align1 {
- struct_span_err!(
- tcx.sess,
- span,
- E0691,
- "zero-sized field in transparent {} has alignment larger than 1",
- adt.descr(),
- )
- .span_label(span, "has alignment larger than 1")
- .emit();
- }
- if incompat && let Some((descr, def_id, substs, non_exhaustive)) = non_exhaustive {
- tcx.struct_span_lint_hir(
- REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS,
- tcx.hir().local_def_id_to_hir_id(adt.did().expect_local()),
- span,
- |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_attr(def_id.to_def_id(), sym::repr) {
- 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();
- }
- }
-
- let mut disr_vals: Vec<Discr<'tcx>> = Vec::with_capacity(vs.len());
- // This tracks the previous variant span (in the loop) incase we need it for diagnostics
- let mut prev_variant_span: Span = DUMMY_SP;
- for ((_, discr), v) in iter::zip(def.discriminants(tcx), vs) {
- // Check for duplicate discriminant values
- if let Some(i) = disr_vals.iter().position(|&x| x.val == discr.val) {
- let variant_did = def.variant(VariantIdx::new(i)).def_id;
- let variant_i_hir_id = tcx.hir().local_def_id_to_hir_id(variant_did.expect_local());
- let variant_i = tcx.hir().expect_variant(variant_i_hir_id);
- let i_span = match variant_i.disr_expr {
- Some(ref expr) => tcx.hir().span(expr.hir_id),
- None => tcx.def_span(variant_did),
- };
- let span = match v.disr_expr {
- Some(ref expr) => tcx.hir().span(expr.hir_id),
- None => v.span,
- };
- let display_discr = format_discriminant_overflow(tcx, v, discr);
- let display_discr_i = format_discriminant_overflow(tcx, variant_i, disr_vals[i]);
- let no_disr = v.disr_expr.is_none();
- let mut err = struct_span_err!(
- tcx.sess,
- sp,
- E0081,
- "discriminant value `{}` assigned more than once",
- discr,
- );
-
- err.span_label(i_span, format!("first assignment of {display_discr_i}"));
- err.span_label(span, format!("second assignment of {display_discr}"));
-
- if no_disr {
- err.span_label(
- prev_variant_span,
- format!(
- "assigned discriminant for `{}` was incremented from this discriminant",
- v.ident
- ),
- );
- }
- err.emit();
- }
-
- disr_vals.push(discr);
- prev_variant_span = v.span;
- }
-
- check_representable(tcx, sp, def_id);
- check_transparent(tcx, sp, def);
-}
-
-/// In the case that a discriminant is both a duplicate and an overflowing literal,
-/// we insert both the assigned discriminant and the literal it overflowed from into the formatted
-/// output. Otherwise we format the discriminant normally.
-fn format_discriminant_overflow<'tcx>(
- tcx: TyCtxt<'tcx>,
- variant: &hir::Variant<'_>,
- dis: Discr<'tcx>,
-) -> String {
- if let Some(expr) = &variant.disr_expr {
- let body = &tcx.hir().body(expr.body).value;
- if let hir::ExprKind::Lit(lit) = &body.kind
- && let rustc_ast::LitKind::Int(lit_value, _int_kind) = &lit.node
- && dis.val != *lit_value
- {
- return format!("`{dis}` (overflowed from `{lit_value}`)");
- }
- }
-
- format!("`{dis}`")
-}
-
-pub(super) fn check_type_params_are_used<'tcx>(
- tcx: TyCtxt<'tcx>,
- generics: &ty::Generics,
- ty: Ty<'tcx>,
-) {
- debug!("check_type_params_are_used(generics={:?}, ty={:?})", generics, ty);
-
- assert_eq!(generics.parent, None);
-
- if generics.own_counts().types == 0 {
- return;
- }
-
- let mut params_used = BitSet::new_empty(generics.params.len());
-
- if ty.references_error() {
- // If there is already another error, do not emit
- // an error for not using a type parameter.
- assert!(tcx.sess.has_errors().is_some());
- return;
- }
-
- for leaf in ty.walk() {
- if let GenericArgKind::Type(leaf_ty) = leaf.unpack()
- && let ty::Param(param) = leaf_ty.kind()
- {
- debug!("found use of ty param {:?}", param);
- params_used.insert(param.index);
- }
- }
-
- for param in &generics.params {
- if !params_used.contains(param.index)
- && let ty::GenericParamDefKind::Type { .. } = param.kind
- {
- let span = tcx.def_span(param.def_id);
- struct_span_err!(
- tcx.sess,
- span,
- E0091,
- "type parameter `{}` is unused",
- param.name,
- )
- .span_label(span, "unused type parameter")
- .emit();
- }
- }
-}
-
-pub(super) fn check_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
- let module = tcx.hir_module_items(module_def_id);
- for id in module.items() {
- check_item_type(tcx, id);
- }
-}
-
-fn async_opaque_type_cycle_error(tcx: TyCtxt<'_>, span: Span) -> ErrorGuaranteed {
- struct_span_err!(tcx.sess, span, E0733, "recursion in an `async fn` requires boxing")
- .span_label(span, "recursive `async fn`")
- .note("a recursive `async fn` must be rewritten to return a boxed `dyn Future`")
- .note(
- "consider using the `async_recursion` crate: https://crates.io/crates/async_recursion",
- )
- .emit()
-}
-
-/// Emit an error for recursive opaque types.
-///
-/// If this is a return `impl Trait`, find the item's return expressions and point at them. For
-/// direct recursion this is enough, but for indirect recursion also point at the last intermediary
-/// `impl Trait`.
-///
-/// If all the return expressions evaluate to `!`, then we explain that the error will go away
-/// after changing it. This can happen when a user uses `panic!()` or similar as a placeholder.
-fn opaque_type_cycle_error(tcx: TyCtxt<'_>, def_id: LocalDefId, span: Span) -> ErrorGuaranteed {
- let mut err = struct_span_err!(tcx.sess, span, E0720, "cannot resolve opaque type");
-
- let mut label = false;
- if let Some((def_id, visitor)) = get_owner_return_paths(tcx, def_id) {
- let typeck_results = tcx.typeck(def_id);
- if visitor
- .returns
- .iter()
- .filter_map(|expr| typeck_results.node_type_opt(expr.hir_id))
- .all(|ty| matches!(ty.kind(), ty::Never))
- {
- let spans = visitor
- .returns
- .iter()
- .filter(|expr| typeck_results.node_type_opt(expr.hir_id).is_some())
- .map(|expr| expr.span)
- .collect::<Vec<Span>>();
- let span_len = spans.len();
- if span_len == 1 {
- err.span_label(spans[0], "this returned value is of `!` type");
- } else {
- let mut multispan: MultiSpan = spans.clone().into();
- for span in spans {
- multispan.push_span_label(span, "this returned value is of `!` type");
- }
- err.span_note(multispan, "these returned values have a concrete \"never\" type");
- }
- err.help("this error will resolve once the item's body returns a concrete type");
- } else {
- let mut seen = FxHashSet::default();
- seen.insert(span);
- err.span_label(span, "recursive opaque type");
- label = true;
- for (sp, ty) in visitor
- .returns
- .iter()
- .filter_map(|e| typeck_results.node_type_opt(e.hir_id).map(|t| (e.span, t)))
- .filter(|(_, ty)| !matches!(ty.kind(), ty::Never))
- {
- struct OpaqueTypeCollector(Vec<DefId>);
- impl<'tcx> ty::visit::TypeVisitor<'tcx> for OpaqueTypeCollector {
- fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
- match *t.kind() {
- ty::Opaque(def, _) => {
- self.0.push(def);
- ControlFlow::CONTINUE
- }
- _ => t.super_visit_with(self),
- }
- }
- }
- let mut visitor = OpaqueTypeCollector(vec![]);
- ty.visit_with(&mut visitor);
- for def_id in visitor.0 {
- let ty_span = tcx.def_span(def_id);
- if !seen.contains(&ty_span) {
- err.span_label(ty_span, &format!("returning this opaque type `{ty}`"));
- seen.insert(ty_span);
- }
- err.span_label(sp, &format!("returning here with type `{ty}`"));
- }
- }
- }
- }
- if !label {
- err.span_label(span, "cannot resolve opaque type");
- }
- err.emit()
-}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-09 17:02:24 +0000