| 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, ErrorReported}; |
| use rustc_hir as hir; |
| use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE}; |
| use rustc_hir::lang_items::LangItem; |
| use rustc_hir::{ItemKind, Node}; |
| use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; |
| use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt}; |
| use rustc_middle::ty::fold::TypeFoldable; |
| use rustc_middle::ty::subst::GenericArgKind; |
| use rustc_middle::ty::util::{Discr, IntTypeExt, Representability}; |
| use rustc_middle::ty::{self, RegionKind, ToPredicate, Ty, TyCtxt}; |
| use rustc_session::config::EntryFnType; |
| use rustc_span::symbol::sym; |
| use rustc_span::{self, MultiSpan, Span}; |
| use rustc_target::spec::abi::Abi; |
| use rustc_trait_selection::opaque_types::InferCtxtExt as _; |
| use rustc_trait_selection::traits::error_reporting::InferCtxtExt as _; |
| use rustc_trait_selection::traits::{self, ObligationCauseCode}; |
| |
| pub fn check_wf_new(tcx: TyCtxt<'_>) { |
| let visit = wfcheck::CheckTypeWellFormedVisitor::new(tcx); |
| tcx.hir().krate().par_visit_all_item_likes(&visit); |
| } |
| |
| pub(super) fn check_abi(tcx: TyCtxt<'_>, span: Span, abi: Abi) { |
| if !tcx.sess.target.is_abi_supported(abi) { |
| struct_span_err!( |
| tcx.sess, |
| span, |
| E0570, |
| "The ABI `{}` is not supported for the current target", |
| abi |
| ) |
| .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) |
| 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>, |
| ) -> (FnCtxt<'a, 'tcx>, Option<GeneratorTypes<'tcx>>) { |
| let mut fn_sig = fn_sig; |
| |
| debug!("check_fn(sig={:?}, fn_id={}, param_env={:?})", fn_sig, fn_id, param_env); |
| |
| // 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.borrow_mut() = UnsafetyState::function(fn_sig.unsafety, fn_id); |
| |
| let tcx = fcx.tcx; |
| let sess = tcx.sess; |
| let hir = tcx.hir(); |
| |
| let declared_ret_ty = fn_sig.output(); |
| |
| let revealed_ret_ty = |
| fcx.instantiate_opaque_types_from_value(fn_id, &declared_ret_ty, decl.output.span()); |
| debug!("check_fn: declared_ret_ty: {}, revealed_ret_ty: {}", declared_ret_ty, revealed_ret_ty); |
| fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(revealed_ret_ty))); |
| fcx.ret_type_span = Some(decl.output.span()); |
| if let ty::Opaque(..) = declared_ret_ty.kind() { |
| fcx.ret_coercion_impl_trait = Some(declared_ret_ty); |
| } |
| fn_sig = tcx.mk_fn_sig( |
| fn_sig.inputs().iter().cloned(), |
| revealed_ret_ty, |
| fn_sig.c_variadic, |
| fn_sig.unsafety, |
| fn_sig.abi, |
| ); |
| |
| let span = body.value.span; |
| |
| fn_maybe_err(tcx, span, fn_sig.abi); |
| |
| 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)); |
| } |
| |
| let outer_def_id = tcx.closure_base_def_id(hir.local_def_id(fn_id).to_def_id()).expect_local(); |
| let outer_hir_id = hir.local_def_id_to_hir_id(outer_def_id); |
| GatherLocalsVisitor::new(&fcx, outer_hir_id).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.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_locals { |
| 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); |
| tcx.sess.delay_span_bug(decl.output.span(), "`!Sized` return type"); |
| } else { |
| fcx.require_type_is_sized(declared_ret_ty, decl.output.span(), traits::SizedReturnType); |
| fcx.check_return_expr(&body.value); |
| } |
| 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. |
| // |
| // However, the behavior around `!` is sort of complex. In the |
| // event that the `actual_return_ty` comes back as `!`, that |
| // indicates that the fn either does not return or "returns" only |
| // values of type `!`. In this case, if there is an expected |
| // return type that is *not* `!`, that should be ok. But if the |
| // return type is being inferred, we want to "fallback" to `!`: |
| // |
| // let x = move || panic!(); |
| // |
| // To allow for that, I am creating a type variable with diverging |
| // fallback. This was deemed ever so slightly better than unifying |
| // the return value with `!` because it allows for the caller to |
| // make more assumptions about the return type (e.g., they could do |
| // |
| // let y: Option<u32> = Some(x()); |
| // |
| // which would then cause this return type to become `u32`, not |
| // `!`). |
| let coercion = fcx.ret_coercion.take().unwrap().into_inner(); |
| let mut actual_return_ty = coercion.complete(&fcx); |
| if actual_return_ty.is_never() { |
| actual_return_ty = fcx.next_diverging_ty_var(TypeVariableOrigin { |
| kind: TypeVariableOriginKind::DivergingFn, |
| span, |
| }); |
| } |
| fcx.demand_suptype(span, revealed_ret_ty, actual_return_ty); |
| |
| // Check that the main return type implements the termination trait. |
| if let Some(term_id) = tcx.lang_items().termination() { |
| if let Some((def_id, EntryFnType::Main)) = tcx.entry_fn(LOCAL_CRATE) { |
| let main_id = hir.local_def_id_to_hir_id(def_id); |
| if main_id == fn_id { |
| let substs = tcx.mk_substs_trait(declared_ret_ty, &[]); |
| let trait_ref = ty::TraitRef::new(term_id, substs); |
| let return_ty_span = decl.output.span(); |
| let cause = traits::ObligationCause::new( |
| return_ty_span, |
| fn_id, |
| ObligationCauseCode::MainFunctionType, |
| ); |
| |
| inherited.register_predicate(traits::Obligation::new( |
| cause, |
| param_env, |
| trait_ref.without_const().to_predicate(tcx), |
| )); |
| } |
| } |
| } |
| |
| // Check that a function marked as `#[panic_handler]` has signature `fn(&PanicInfo) -> !` |
| if let Some(panic_impl_did) = tcx.lang_items().panic_impl() { |
| if panic_impl_did == hir.local_def_id(fn_id).to_def_id() { |
| if let Some(panic_info_did) = tcx.lang_items().panic_info() { |
| if *declared_ret_ty.kind() != ty::Never { |
| sess.span_err(decl.output.span(), "return type should be `!`"); |
| } |
| |
| let inputs = fn_sig.inputs(); |
| let span = hir.span(fn_id); |
| if inputs.len() == 1 { |
| 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 != RegionKind::ReStatic |
| } |
| _ => false, |
| }, |
| _ => false, |
| }; |
| |
| if !arg_is_panic_info { |
| sess.span_err(decl.inputs[0].span, "argument should be `&PanicInfo`"); |
| } |
| |
| if let Node::Item(item) = hir.get(fn_id) { |
| if let ItemKind::Fn(_, ref generics, _) = item.kind { |
| if !generics.params.is_empty() { |
| sess.span_err(span, "should have no type parameters"); |
| } |
| } |
| } |
| } else { |
| let span = sess.source_map().guess_head_span(span); |
| sess.span_err(span, "function should have one argument"); |
| } |
| } else { |
| sess.err("language item required, but not found: `panic_info`"); |
| } |
| } |
| } |
| |
| // Check that a function marked as `#[alloc_error_handler]` has signature `fn(Layout) -> !` |
| if let Some(alloc_error_handler_did) = tcx.lang_items().oom() { |
| if alloc_error_handler_did == hir.local_def_id(fn_id).to_def_id() { |
| if let Some(alloc_layout_did) = tcx.lang_items().alloc_layout() { |
| if *declared_ret_ty.kind() != ty::Never { |
| sess.span_err(decl.output.span(), "return type should be `!`"); |
| } |
| |
| let inputs = fn_sig.inputs(); |
| let span = hir.span(fn_id); |
| if inputs.len() == 1 { |
| let arg_is_alloc_layout = match inputs[0].kind() { |
| ty::Adt(ref adt, _) => adt.did == alloc_layout_did, |
| _ => false, |
| }; |
| |
| if !arg_is_alloc_layout { |
| sess.span_err(decl.inputs[0].span, "argument should be `Layout`"); |
| } |
| |
| if let Node::Item(item) = hir.get(fn_id) { |
| if let ItemKind::Fn(_, ref generics, _) = item.kind { |
| if !generics.params.is_empty() { |
| sess.span_err( |
| span, |
| "`#[alloc_error_handler]` function should have no type \ |
| parameters", |
| ); |
| } |
| } |
| } |
| } else { |
| let span = sess.source_map().guess_head_span(span); |
| sess.span_err(span, "function should have one argument"); |
| } |
| } else { |
| sess.err("language item required, but not found: `alloc_layout`"); |
| } |
| } |
| } |
| |
| (fcx, gen_ty) |
| } |
| |
| pub(super) fn check_struct(tcx: TyCtxt<'_>, id: hir::HirId, span: Span) { |
| let def_id = tcx.hir().local_def_id(id); |
| let def = tcx.adt_def(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); |
| } |
| |
| pub(super) fn check_union(tcx: TyCtxt<'_>, id: hir::HirId, span: Span) { |
| let def_id = tcx.hir().local_def_id(id); |
| let def = tcx.adt_def(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. |
| pub(super) 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()); |
| let fields = &def.non_enum_variant().fields; |
| let param_env = tcx.param_env(item_def_id); |
| for field in fields { |
| let field_ty = field.ty(tcx, substs); |
| // We are currently checking the type this field came from, so it must be local. |
| let field_span = tcx.hir().span_if_local(field.did).unwrap(); |
| if field_ty.needs_drop(tcx, param_env) { |
| struct_span_err!( |
| tcx.sess, |
| field_span, |
| E0740, |
| "unions may not contain fields that need dropping" |
| ) |
| .span_note(field_span, "`std::mem::ManuallyDrop` can be used to wrap the type") |
| .emit(); |
| return false; |
| } |
| } |
| } else { |
| span_bug!(span, "unions must be ty::Adt, but got {:?}", item_type.kind()); |
| } |
| true |
| } |
| |
| /// 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>, |
| span: Span, |
| origin: &hir::OpaqueTyOrigin, |
| ) { |
| 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". |
| pub(super) fn check_opaque_for_inheriting_lifetimes( |
| tcx: TyCtxt<'tcx>, |
| def_id: LocalDefId, |
| span: Span, |
| ) { |
| let item = tcx.hir().expect_item(tcx.hir().local_def_id_to_hir_id(def_id)); |
| debug!( |
| "check_opaque_for_inheriting_lifetimes: def_id={:?} span={:?} item={:?}", |
| def_id, span, item |
| ); |
| |
| #[derive(Debug)] |
| struct ProhibitOpaqueVisitor<'tcx> { |
| opaque_identity_ty: Ty<'tcx>, |
| generics: &'tcx ty::Generics, |
| ty: Option<Ty<'tcx>>, |
| }; |
| |
| impl<'tcx> ty::fold::TypeVisitor<'tcx> for ProhibitOpaqueVisitor<'tcx> { |
| fn visit_ty(&mut self, t: Ty<'tcx>) -> bool { |
| debug!("check_opaque_for_inheriting_lifetimes: (visit_ty) t={:?}", t); |
| if t != self.opaque_identity_ty && t.super_visit_with(self) { |
| self.ty = Some(t); |
| return true; |
| } |
| false |
| } |
| |
| fn visit_region(&mut self, r: ty::Region<'tcx>) -> bool { |
| debug!("check_opaque_for_inheriting_lifetimes: (visit_region) r={:?}", r); |
| if let RegionKind::ReEarlyBound(ty::EarlyBoundRegion { index, .. }) = r { |
| return *index < self.generics.parent_count as u32; |
| } |
| |
| r.super_visit_with(self) |
| } |
| |
| fn visit_const(&mut self, c: &'tcx ty::Const<'tcx>) -> bool { |
| if let ty::ConstKind::Unevaluated(..) = c.val { |
| // FIXME(#72219) We currenctly 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 false; |
| } |
| c.super_visit_with(self) |
| } |
| } |
| |
| 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), |
| ty: None, |
| }; |
| let prohibit_opaque = tcx |
| .explicit_item_bounds(def_id) |
| .iter() |
| .any(|(predicate, _)| predicate.visit_with(&mut visitor)); |
| debug!( |
| "check_opaque_for_inheriting_lifetimes: prohibit_opaque={:?}, visitor={:?}", |
| prohibit_opaque, visitor |
| ); |
| |
| if prohibit_opaque { |
| let is_async = match item.kind { |
| ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => match origin { |
| hir::OpaqueTyOrigin::AsyncFn => true, |
| _ => false, |
| }, |
| _ => 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" }, |
| ); |
| |
| if let Ok(snippet) = tcx.sess.source_map().span_to_snippet(span) { |
| if snippet == "Self" { |
| if let Some(ty) = visitor.ty { |
| err.span_suggestion( |
| span, |
| "consider spelling out the type instead", |
| 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<(), ErrorReported> { |
| if let Err(partially_expanded_type) = tcx.try_expand_impl_trait_type(def_id.to_def_id(), substs) |
| { |
| match origin { |
| hir::OpaqueTyOrigin::AsyncFn => async_opaque_type_cycle_error(tcx, span), |
| hir::OpaqueTyOrigin::Binding => { |
| binding_opaque_type_cycle_error(tcx, def_id, span, partially_expanded_type) |
| } |
| _ => opaque_type_cycle_error(tcx, def_id, span), |
| } |
| Err(ErrorReported) |
| } 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 ()>>`. |
| fn check_opaque_meets_bounds<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| def_id: LocalDefId, |
| substs: SubstsRef<'tcx>, |
| span: Span, |
| origin: &hir::OpaqueTyOrigin, |
| ) { |
| match origin { |
| // Checked when type checking the function containing them. |
| hir::OpaqueTyOrigin::FnReturn | hir::OpaqueTyOrigin::AsyncFn => return, |
| // Can have different predicates to their defining use |
| hir::OpaqueTyOrigin::Binding | hir::OpaqueTyOrigin::Misc => {} |
| } |
| |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
| let param_env = tcx.param_env(def_id); |
| |
| tcx.infer_ctxt().enter(move |infcx| { |
| let inh = Inherited::new(infcx, def_id); |
| let infcx = &inh.infcx; |
| let opaque_ty = tcx.mk_opaque(def_id.to_def_id(), substs); |
| |
| let misc_cause = traits::ObligationCause::misc(span, hir_id); |
| |
| let (_, opaque_type_map) = inh.register_infer_ok_obligations( |
| infcx.instantiate_opaque_types(def_id, hir_id, param_env, &opaque_ty, span), |
| ); |
| |
| for (def_id, opaque_defn) in opaque_type_map { |
| match infcx |
| .at(&misc_cause, param_env) |
| .eq(opaque_defn.concrete_ty, tcx.type_of(def_id).subst(tcx, opaque_defn.substs)) |
| { |
| Ok(infer_ok) => inh.register_infer_ok_obligations(infer_ok), |
| Err(ty_err) => tcx.sess.delay_span_bug( |
| opaque_defn.definition_span, |
| &format!( |
| "could not unify `{}` with revealed type:\n{}", |
| opaque_defn.concrete_ty, ty_err, |
| ), |
| ), |
| } |
| } |
| |
| // Check that all obligations are satisfied by the implementation's |
| // version. |
| if let Err(ref errors) = inh.fulfillment_cx.borrow_mut().select_all_or_error(&infcx) { |
| infcx.report_fulfillment_errors(errors, None, false); |
| } |
| |
| // Finally, resolve all regions. This catches wily misuses of |
| // lifetime parameters. |
| let fcx = FnCtxt::new(&inh, param_env, hir_id); |
| fcx.regionck_item(hir_id, span, &[]); |
| }); |
| } |
| |
| pub fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, it: &'tcx hir::Item<'tcx>) { |
| debug!( |
| "check_item_type(it.hir_id={}, it.name={})", |
| it.hir_id, |
| tcx.def_path_str(tcx.hir().local_def_id(it.hir_id).to_def_id()) |
| ); |
| let _indenter = indenter(); |
| match it.kind { |
| // Consts can play a role in type-checking, so they are included here. |
| hir::ItemKind::Static(..) => { |
| let def_id = tcx.hir().local_def_id(it.hir_id); |
| tcx.ensure().typeck(def_id); |
| maybe_check_static_with_link_section(tcx, def_id, it.span); |
| } |
| hir::ItemKind::Const(..) => { |
| tcx.ensure().typeck(tcx.hir().local_def_id(it.hir_id)); |
| } |
| hir::ItemKind::Enum(ref enum_definition, _) => { |
| check_enum(tcx, it.span, &enum_definition.variants, it.hir_id); |
| } |
| hir::ItemKind::Fn(..) => {} // entirely within check_item_body |
| hir::ItemKind::Impl { ref items, .. } => { |
| debug!("ItemKind::Impl {} with id {}", it.ident, it.hir_id); |
| let impl_def_id = tcx.hir().local_def_id(it.hir_id); |
| if let Some(impl_trait_ref) = tcx.impl_trait_ref(impl_def_id) { |
| check_impl_items_against_trait(tcx, it.span, impl_def_id, impl_trait_ref, items); |
| let trait_def_id = impl_trait_ref.def_id; |
| check_on_unimplemented(tcx, trait_def_id, it); |
| } |
| } |
| hir::ItemKind::Trait(_, _, _, _, ref items) => { |
| let def_id = tcx.hir().local_def_id(it.hir_id); |
| check_on_unimplemented(tcx, def_id.to_def_id(), 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 item_def_id = tcx.hir().local_def_id(item.hir_id).to_def_id(); |
| let assoc_item = tcx.associated_item(item_def_id); |
| let trait_substs = |
| InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); |
| let _: Result<_, rustc_errors::ErrorReported> = check_type_bounds( |
| tcx, |
| assoc_item, |
| assoc_item, |
| item.span, |
| ty::TraitRef { def_id: def_id.to_def_id(), substs: trait_substs }, |
| ); |
| } |
| _ => {} |
| } |
| } |
| } |
| hir::ItemKind::Struct(..) => { |
| check_struct(tcx, it.hir_id, it.span); |
| } |
| hir::ItemKind::Union(..) => { |
| check_union(tcx, it.hir_id, it.span); |
| } |
| hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => { |
| // 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 def_id = tcx.hir().local_def_id(it.hir_id); |
| |
| let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); |
| check_opaque(tcx, def_id, substs, it.span, &origin); |
| } |
| } |
| hir::ItemKind::TyAlias(..) => { |
| let def_id = tcx.hir().local_def_id(it.hir_id); |
| let pty_ty = tcx.type_of(def_id); |
| let generics = tcx.generics_of(def_id); |
| check_type_params_are_used(tcx, &generics, pty_ty); |
| } |
| hir::ItemKind::ForeignMod(ref m) => { |
| check_abi(tcx, it.span, m.abi); |
| |
| if m.abi == Abi::RustIntrinsic { |
| for item in m.items { |
| intrinsic::check_intrinsic_type(tcx, item); |
| } |
| } else if m.abi == Abi::PlatformIntrinsic { |
| for item in m.items { |
| intrinsic::check_platform_intrinsic_type(tcx, item); |
| } |
| } else { |
| for item in m.items { |
| let generics = tcx.generics_of(tcx.hir().local_def_id(item.hir_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 {} parameters", |
| kinds, |
| ) |
| .span_label(item.span, &format!("can't have {} parameters", kinds)) |
| .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(); |
| } |
| |
| if let hir::ForeignItemKind::Fn(ref fn_decl, _, _) = item.kind { |
| require_c_abi_if_c_variadic(tcx, fn_decl, m.abi, item.span); |
| } |
| } |
| } |
| } |
| _ => { /* nothing to do */ } |
| } |
| } |
| |
| pub(super) fn check_on_unimplemented(tcx: TyCtxt<'_>, trait_def_id: DefId, item: &hir::Item<'_>) { |
| let item_def_id = tcx.hir().local_def_id(item.hir_id); |
| // an error would be reported if this fails. |
| let _ = traits::OnUnimplementedDirective::of_item(tcx, trait_def_id, 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::ImplItem<'_>, |
| ) { |
| let kind = match impl_item.kind { |
| hir::ImplItemKind::Const(..) => ty::AssocKind::Const, |
| hir::ImplItemKind::Fn(..) => ty::AssocKind::Fn, |
| hir::ImplItemKind::TyAlias(_) => ty::AssocKind::Type, |
| }; |
| |
| let ancestors = match trait_def.ancestors(tcx, impl_id) { |
| Ok(ancestors) => ancestors, |
| Err(_) => 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.ident, kind, trait_def.def_id))) |
| } |
| }) |
| .peekable(); |
| |
| if ancestor_impls.peek().is_none() { |
| // No parent, nothing to specialize. |
| return; |
| } |
| |
| 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); |
| } |
| } |
| |
| pub(super) 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<'_>], |
| ) { |
| let impl_span = tcx.sess.source_map().guess_head_span(full_impl_span); |
| |
| // 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; |
| } |
| } |
| |
| // Locate trait definition and items |
| let trait_def = tcx.trait_def(impl_trait_ref.def_id); |
| |
| let impl_items = || impl_item_refs.iter().map(|iiref| tcx.hir().impl_item(iiref.id)); |
| |
| // Check existing impl methods to see if they are both present in trait |
| // and compatible with trait signature |
| for impl_item in impl_items() { |
| let namespace = impl_item.kind.namespace(); |
| let ty_impl_item = tcx.associated_item(tcx.hir().local_def_id(impl_item.hir_id)); |
| let ty_trait_item = tcx |
| .associated_items(impl_trait_ref.def_id) |
| .find_by_name_and_namespace(tcx, ty_impl_item.ident, namespace, impl_trait_ref.def_id) |
| .or_else(|| { |
| // Not compatible, but needed for the error message |
| tcx.associated_items(impl_trait_ref.def_id) |
| .filter_by_name(tcx, ty_impl_item.ident, impl_trait_ref.def_id) |
| .next() |
| }); |
| |
| // Check that impl definition matches trait definition |
| if let Some(ty_trait_item) = ty_trait_item { |
| match impl_item.kind { |
| hir::ImplItemKind::Const(..) => { |
| // Find associated const definition. |
| if ty_trait_item.kind == ty::AssocKind::Const { |
| compare_const_impl( |
| tcx, |
| &ty_impl_item, |
| impl_item.span, |
| &ty_trait_item, |
| impl_trait_ref, |
| ); |
| } else { |
| let mut err = struct_span_err!( |
| tcx.sess, |
| impl_item.span, |
| E0323, |
| "item `{}` is an associated const, \ |
| which doesn't match its trait `{}`", |
| ty_impl_item.ident, |
| impl_trait_ref.print_only_trait_path() |
| ); |
| err.span_label(impl_item.span, "does not match trait"); |
| // We can only get the spans from local trait definition |
| // Same for E0324 and E0325 |
| if let Some(trait_span) = tcx.hir().span_if_local(ty_trait_item.def_id) { |
| err.span_label(trait_span, "item in trait"); |
| } |
| err.emit() |
| } |
| } |
| hir::ImplItemKind::Fn(..) => { |
| let opt_trait_span = tcx.hir().span_if_local(ty_trait_item.def_id); |
| if ty_trait_item.kind == ty::AssocKind::Fn { |
| compare_impl_method( |
| tcx, |
| &ty_impl_item, |
| impl_item.span, |
| &ty_trait_item, |
| impl_trait_ref, |
| opt_trait_span, |
| ); |
| } else { |
| let mut err = struct_span_err!( |
| tcx.sess, |
| impl_item.span, |
| E0324, |
| "item `{}` is an associated method, \ |
| which doesn't match its trait `{}`", |
| ty_impl_item.ident, |
| impl_trait_ref.print_only_trait_path() |
| ); |
| err.span_label(impl_item.span, "does not match trait"); |
| if let Some(trait_span) = opt_trait_span { |
| err.span_label(trait_span, "item in trait"); |
| } |
| err.emit() |
| } |
| } |
| hir::ImplItemKind::TyAlias(_) => { |
| let opt_trait_span = tcx.hir().span_if_local(ty_trait_item.def_id); |
| if ty_trait_item.kind == ty::AssocKind::Type { |
| compare_ty_impl( |
| tcx, |
| &ty_impl_item, |
| impl_item.span, |
| &ty_trait_item, |
| impl_trait_ref, |
| opt_trait_span, |
| ); |
| } else { |
| let mut err = struct_span_err!( |
| tcx.sess, |
| impl_item.span, |
| E0325, |
| "item `{}` is an associated type, \ |
| which doesn't match its trait `{}`", |
| ty_impl_item.ident, |
| impl_trait_ref.print_only_trait_path() |
| ); |
| err.span_label(impl_item.span, "does not match trait"); |
| if let Some(trait_span) = opt_trait_span { |
| err.span_label(trait_span, "item in trait"); |
| } |
| err.emit() |
| } |
| } |
| } |
| |
| check_specialization_validity( |
| tcx, |
| trait_def, |
| &ty_trait_item, |
| impl_id.to_def_id(), |
| impl_item, |
| ); |
| } |
| } |
| |
| // Check for missing items from trait |
| let mut missing_items = Vec::new(); |
| if let Ok(ancestors) = trait_def.ancestors(tcx, impl_id.to_def_id()) { |
| for trait_item in tcx.associated_items(impl_trait_ref.def_id).in_definition_order() { |
| let is_implemented = ancestors |
| .leaf_def(tcx, trait_item.ident, trait_item.kind) |
| .map(|node_item| !node_item.defining_node.is_from_trait()) |
| .unwrap_or(false); |
| |
| if !is_implemented && tcx.impl_defaultness(impl_id).is_final() { |
| if !trait_item.defaultness.has_value() { |
| missing_items.push(*trait_item); |
| } |
| } |
| } |
| } |
| |
| if !missing_items.is_empty() { |
| missing_items_err(tcx, impl_span, &missing_items, full_impl_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 rty.is_representable(tcx, sp) { |
| 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() { |
| if 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; |
| } |
| match e.kind() { |
| ty::Param(_) => { /* struct<T>(T, T, T, T) is ok */ } |
| _ if e.is_machine() => { /* struct(u8, u8, u8, u8) is ok */ } |
| _ => { |
| struct_span_err!( |
| tcx.sess, |
| sp, |
| E0077, |
| "SIMD vector element type should be machine 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).iter() { |
| for r in attr::find_repr_attrs(&tcx.sess, attr) { |
| if let attr::ReprPacked(pack) = r { |
| if let Some(repr_pack) = repr.pack { |
| if 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() { |
| if !stack.contains(&def.did) { |
| if let Some(mut defs) = check_packed_inner(tcx, def.did, stack) { |
| defs.push((def.did, field.ident.span)); |
| return Some(defs); |
| } |
| } |
| } |
| } |
| stack.pop(); |
| } |
| } |
| |
| None |
| } |
| |
| pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, adt: &'tcx ty::AdtDef) { |
| if !adt.repr.transparent() { |
| return; |
| } |
| let sp = tcx.sess.source_map().guess_head_span(sp); |
| |
| 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) |
| 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(|layout| layout.is_zst()).unwrap_or(false); |
| let align1 = layout.map(|layout| layout.align.abi.bytes() == 1).unwrap_or(false); |
| (span, zst, align1) |
| }); |
| |
| let non_zst_fields = |
| field_infos.clone().filter_map(|(span, zst, _align1)| if !zst { Some(span) } else { None }); |
| let non_zst_count = non_zst_fields.clone().count(); |
| if non_zst_count != 1 { |
| bad_non_zero_sized_fields(tcx, adt, non_zst_count, non_zst_fields, sp); |
| } |
| for (span, zst, align1) 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(); |
| } |
| } |
| } |
| |
| #[allow(trivial_numeric_casts)] |
| pub fn check_enum<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| sp: Span, |
| vs: &'tcx [hir::Variant<'tcx>], |
| id: hir::HirId, |
| ) { |
| let def_id = tcx.hir().local_def_id(id); |
| let def = tcx.adt_def(def_id); |
| def.destructor(tcx); // force the destructor to be evaluated |
| |
| if vs.is_empty() { |
| let attributes = tcx.get_attrs(def_id.to_def_id()); |
| if let Some(attr) = tcx.sess.find_by_name(&attributes, 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<'_>| match var.data { |
| hir::VariantData::Unit(..) => true, |
| _ => false, |
| }; |
| |
| 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()); |
| for ((_, discr), v) in def.discriminants(tcx).zip(vs) { |
| // Check for duplicate discriminant values |
| if let Some(i) = disr_vals.iter().position(|&x| x.val == discr.val) { |
| let variant_did = def.variants[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.hir().span(variant_i_hir_id), |
| }; |
| let span = match v.disr_expr { |
| Some(ref expr) => tcx.hir().span(expr.hir_id), |
| None => v.span, |
| }; |
| struct_span_err!( |
| tcx.sess, |
| span, |
| E0081, |
| "discriminant value `{}` already exists", |
| disr_vals[i] |
| ) |
| .span_label(i_span, format!("first use of `{}`", disr_vals[i])) |
| .span_label(span, format!("enum already has `{}`", disr_vals[i])) |
| .emit(); |
| } |
| disr_vals.push(discr); |
| } |
| |
| check_representable(tcx, sp, def_id); |
| check_transparent(tcx, sp, def); |
| } |
| |
| 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()); |
| return; |
| } |
| |
| for leaf in ty.walk() { |
| if let GenericArgKind::Type(leaf_ty) = leaf.unpack() { |
| if 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) { |
| if 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) { |
| tcx.hir().visit_item_likes_in_module(module_def_id, &mut CheckItemTypesVisitor { tcx }); |
| } |
| |
| pub(super) fn check_item_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) { |
| wfcheck::check_item_well_formed(tcx, def_id); |
| } |
| |
| pub(super) fn check_trait_item_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) { |
| wfcheck::check_trait_item(tcx, def_id); |
| } |
| |
| pub(super) fn check_impl_item_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) { |
| wfcheck::check_impl_item(tcx, def_id); |
| } |
| |
| fn async_opaque_type_cycle_error(tcx: TyCtxt<'tcx>, span: Span) { |
| 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`") |
| .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<'tcx>, def_id: LocalDefId, span: Span) { |
| let mut err = struct_span_err!(tcx.sess, span, E0720, "cannot resolve opaque type"); |
| |
| let mut label = false; |
| if let Some((hir_id, visitor)) = get_owner_return_paths(tcx, def_id) { |
| let typeck_results = tcx.typeck(tcx.hir().local_def_id(hir_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".to_string()); |
| } |
| 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 VisitTypes(Vec<DefId>); |
| impl<'tcx> ty::fold::TypeVisitor<'tcx> for VisitTypes { |
| fn visit_ty(&mut self, t: Ty<'tcx>) -> bool { |
| match *t.kind() { |
| ty::Opaque(def, _) => { |
| self.0.push(def); |
| false |
| } |
| _ => t.super_visit_with(self), |
| } |
| } |
| } |
| let mut visitor = VisitTypes(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(); |
| } |
