+++ /dev/null
-//! "Collection" is the process of determining the type and other external
-//! details of each item in Rust. Collection is specifically concerned
-//! with *inter-procedural* things -- for example, for a function
-//! definition, collection will figure out the type and signature of the
-//! function, but it will not visit the *body* of the function in any way,
-//! nor examine type annotations on local variables (that's the job of
-//! type *checking*).
-//!
-//! Collecting is ultimately defined by a bundle of queries that
-//! inquire after various facts about the items in the crate (e.g.,
-//! `type_of`, `generics_of`, `predicates_of`, etc). See the `provide` function
-//! for the full set.
-//!
-//! At present, however, we do run collection across all items in the
-//! crate as a kind of pass. This should eventually be factored away.
-
-use crate::astconv::AstConv;
-use crate::bounds::Bounds;
-use crate::check::intrinsic::intrinsic_operation_unsafety;
-use crate::constrained_generic_params as cgp;
-use crate::errors;
-use crate::middle::resolve_lifetime as rl;
-use rustc_ast as ast;
-use rustc_ast::{MetaItemKind, NestedMetaItem};
-use rustc_attr::{list_contains_name, InlineAttr, InstructionSetAttr, OptimizeAttr};
-use rustc_data_structures::captures::Captures;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
-use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed, StashKey};
-use rustc_hir as hir;
-use rustc_hir::def::{CtorKind, DefKind};
-use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
-use rustc_hir::intravisit::{self, Visitor};
-use rustc_hir::weak_lang_items;
-use rustc_hir::{GenericParamKind, HirId, Node};
-use rustc_middle::hir::nested_filter;
-use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
-use rustc_middle::mir::mono::Linkage;
-use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::subst::InternalSubsts;
-use rustc_middle::ty::util::Discr;
-use rustc_middle::ty::util::IntTypeExt;
-use rustc_middle::ty::{self, AdtKind, Const, DefIdTree, IsSuggestable, Ty, TyCtxt};
-use rustc_middle::ty::{ReprOptions, ToPredicate};
-use rustc_session::lint;
-use rustc_session::parse::feature_err;
-use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::{Span, DUMMY_SP};
-use rustc_target::spec::{abi, SanitizerSet};
-use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName;
-use std::iter;
-
-mod item_bounds;
-mod type_of;
-
-#[derive(Debug)]
-struct OnlySelfBounds(bool);
-
-///////////////////////////////////////////////////////////////////////////
-// Main entry point
-
-fn collect_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
- tcx.hir().visit_item_likes_in_module(module_def_id, &mut CollectItemTypesVisitor { tcx });
-}
-
-pub fn provide(providers: &mut Providers) {
- *providers = Providers {
- opt_const_param_of: type_of::opt_const_param_of,
- type_of: type_of::type_of,
- item_bounds: item_bounds::item_bounds,
- explicit_item_bounds: item_bounds::explicit_item_bounds,
- generics_of,
- predicates_of,
- predicates_defined_on,
- explicit_predicates_of,
- super_predicates_of,
- super_predicates_that_define_assoc_type,
- trait_explicit_predicates_and_bounds,
- type_param_predicates,
- trait_def,
- adt_def,
- fn_sig,
- impl_trait_ref,
- impl_polarity,
- is_foreign_item,
- generator_kind,
- codegen_fn_attrs,
- asm_target_features,
- collect_mod_item_types,
- should_inherit_track_caller,
- ..*providers
- };
-}
-
-///////////////////////////////////////////////////////////////////////////
-
-/// Context specific to some particular item. This is what implements
-/// [`AstConv`].
-///
-/// # `ItemCtxt` vs `FnCtxt`
-///
-/// `ItemCtxt` is primarily used to type-check item signatures and lower them
-/// from HIR to their [`ty::Ty`] representation, which is exposed using [`AstConv`].
-/// It's also used for the bodies of items like structs where the body (the fields)
-/// are just signatures.
-///
-/// This is in contrast to [`FnCtxt`], which is used to type-check bodies of
-/// functions, closures, and `const`s -- anywhere that expressions and statements show up.
-///
-/// An important thing to note is that `ItemCtxt` does no inference -- it has no [`InferCtxt`] --
-/// while `FnCtxt` does do inference.
-///
-/// [`FnCtxt`]: crate::check::FnCtxt
-/// [`InferCtxt`]: rustc_infer::infer::InferCtxt
-///
-/// # Trait predicates
-///
-/// `ItemCtxt` has information about the predicates that are defined
-/// on the trait. Unfortunately, this predicate information is
-/// available in various different forms at various points in the
-/// process. So we can't just store a pointer to e.g., the AST or the
-/// parsed ty form, we have to be more flexible. To this end, the
-/// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy
-/// `get_type_parameter_bounds` requests, drawing the information from
-/// the AST (`hir::Generics`), recursively.
-pub struct ItemCtxt<'tcx> {
- tcx: TyCtxt<'tcx>,
- item_def_id: DefId,
-}
-
-///////////////////////////////////////////////////////////////////////////
-
-#[derive(Default)]
-pub(crate) struct HirPlaceholderCollector(pub(crate) Vec<Span>);
-
-impl<'v> Visitor<'v> for HirPlaceholderCollector {
- fn visit_ty(&mut self, t: &'v hir::Ty<'v>) {
- if let hir::TyKind::Infer = t.kind {
- self.0.push(t.span);
- }
- intravisit::walk_ty(self, t)
- }
- fn visit_generic_arg(&mut self, generic_arg: &'v hir::GenericArg<'v>) {
- match generic_arg {
- hir::GenericArg::Infer(inf) => {
- self.0.push(inf.span);
- intravisit::walk_inf(self, inf);
- }
- hir::GenericArg::Type(t) => self.visit_ty(t),
- _ => {}
- }
- }
- fn visit_array_length(&mut self, length: &'v hir::ArrayLen) {
- if let &hir::ArrayLen::Infer(_, span) = length {
- self.0.push(span);
- }
- intravisit::walk_array_len(self, length)
- }
-}
-
-struct CollectItemTypesVisitor<'tcx> {
- tcx: TyCtxt<'tcx>,
-}
-
-/// If there are any placeholder types (`_`), emit an error explaining that this is not allowed
-/// and suggest adding type parameters in the appropriate place, taking into consideration any and
-/// all already existing generic type parameters to avoid suggesting a name that is already in use.
-pub(crate) fn placeholder_type_error<'tcx>(
- tcx: TyCtxt<'tcx>,
- generics: Option<&hir::Generics<'_>>,
- placeholder_types: Vec<Span>,
- suggest: bool,
- hir_ty: Option<&hir::Ty<'_>>,
- kind: &'static str,
-) {
- if placeholder_types.is_empty() {
- return;
- }
-
- placeholder_type_error_diag(tcx, generics, placeholder_types, vec![], suggest, hir_ty, kind)
- .emit();
-}
-
-pub(crate) fn placeholder_type_error_diag<'tcx>(
- tcx: TyCtxt<'tcx>,
- generics: Option<&hir::Generics<'_>>,
- placeholder_types: Vec<Span>,
- additional_spans: Vec<Span>,
- suggest: bool,
- hir_ty: Option<&hir::Ty<'_>>,
- kind: &'static str,
-) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
- if placeholder_types.is_empty() {
- return bad_placeholder(tcx, additional_spans, kind);
- }
-
- let params = generics.map(|g| g.params).unwrap_or_default();
- let type_name = params.next_type_param_name(None);
- let mut sugg: Vec<_> =
- placeholder_types.iter().map(|sp| (*sp, (*type_name).to_string())).collect();
-
- if let Some(generics) = generics {
- if let Some(arg) = params.iter().find(|arg| {
- matches!(arg.name, hir::ParamName::Plain(Ident { name: kw::Underscore, .. }))
- }) {
- // Account for `_` already present in cases like `struct S<_>(_);` and suggest
- // `struct S<T>(T);` instead of `struct S<_, T>(T);`.
- sugg.push((arg.span, (*type_name).to_string()));
- } else if let Some(span) = generics.span_for_param_suggestion() {
- // Account for bounds, we want `fn foo<T: E, K>(_: K)` not `fn foo<T, K: E>(_: K)`.
- sugg.push((span, format!(", {}", type_name)));
- } else {
- sugg.push((generics.span, format!("<{}>", type_name)));
- }
- }
-
- let mut err =
- bad_placeholder(tcx, placeholder_types.into_iter().chain(additional_spans).collect(), kind);
-
- // Suggest, but only if it is not a function in const or static
- if suggest {
- let mut is_fn = false;
- let mut is_const_or_static = false;
-
- if let Some(hir_ty) = hir_ty && let hir::TyKind::BareFn(_) = hir_ty.kind {
- is_fn = true;
-
- // Check if parent is const or static
- let parent_id = tcx.hir().get_parent_node(hir_ty.hir_id);
- let parent_node = tcx.hir().get(parent_id);
-
- is_const_or_static = matches!(
- parent_node,
- Node::Item(&hir::Item {
- kind: hir::ItemKind::Const(..) | hir::ItemKind::Static(..),
- ..
- }) | Node::TraitItem(&hir::TraitItem {
- kind: hir::TraitItemKind::Const(..),
- ..
- }) | Node::ImplItem(&hir::ImplItem { kind: hir::ImplItemKind::Const(..), .. })
- );
- }
-
- // if function is wrapped around a const or static,
- // then don't show the suggestion
- if !(is_fn && is_const_or_static) {
- err.multipart_suggestion(
- "use type parameters instead",
- sugg,
- Applicability::HasPlaceholders,
- );
- }
- }
-
- err
-}
-
-fn reject_placeholder_type_signatures_in_item<'tcx>(
- tcx: TyCtxt<'tcx>,
- item: &'tcx hir::Item<'tcx>,
-) {
- let (generics, suggest) = match &item.kind {
- hir::ItemKind::Union(_, generics)
- | hir::ItemKind::Enum(_, generics)
- | hir::ItemKind::TraitAlias(generics, _)
- | hir::ItemKind::Trait(_, _, generics, ..)
- | hir::ItemKind::Impl(hir::Impl { generics, .. })
- | hir::ItemKind::Struct(_, generics) => (generics, true),
- hir::ItemKind::OpaqueTy(hir::OpaqueTy { generics, .. })
- | hir::ItemKind::TyAlias(_, generics) => (generics, false),
- // `static`, `fn` and `const` are handled elsewhere to suggest appropriate type.
- _ => return,
- };
-
- let mut visitor = HirPlaceholderCollector::default();
- visitor.visit_item(item);
-
- placeholder_type_error(tcx, Some(generics), visitor.0, suggest, None, item.kind.descr());
-}
-
-impl<'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'tcx> {
- type NestedFilter = nested_filter::OnlyBodies;
-
- fn nested_visit_map(&mut self) -> Self::Map {
- self.tcx.hir()
- }
-
- fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
- convert_item(self.tcx, item.item_id());
- reject_placeholder_type_signatures_in_item(self.tcx, item);
- intravisit::walk_item(self, item);
- }
-
- fn visit_generics(&mut self, generics: &'tcx hir::Generics<'tcx>) {
- for param in generics.params {
- match param.kind {
- hir::GenericParamKind::Lifetime { .. } => {}
- hir::GenericParamKind::Type { default: Some(_), .. } => {
- let def_id = self.tcx.hir().local_def_id(param.hir_id);
- self.tcx.ensure().type_of(def_id);
- }
- hir::GenericParamKind::Type { .. } => {}
- hir::GenericParamKind::Const { default, .. } => {
- let def_id = self.tcx.hir().local_def_id(param.hir_id);
- self.tcx.ensure().type_of(def_id);
- if let Some(default) = default {
- let default_def_id = self.tcx.hir().local_def_id(default.hir_id);
- // need to store default and type of default
- self.tcx.ensure().type_of(default_def_id);
- self.tcx.ensure().const_param_default(def_id);
- }
- }
- }
- }
- intravisit::walk_generics(self, generics);
- }
-
- fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
- if let hir::ExprKind::Closure { .. } = expr.kind {
- let def_id = self.tcx.hir().local_def_id(expr.hir_id);
- self.tcx.ensure().generics_of(def_id);
- // We do not call `type_of` for closures here as that
- // depends on typecheck and would therefore hide
- // any further errors in case one typeck fails.
- }
- intravisit::walk_expr(self, expr);
- }
-
- fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
- convert_trait_item(self.tcx, trait_item.trait_item_id());
- intravisit::walk_trait_item(self, trait_item);
- }
-
- fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
- convert_impl_item(self.tcx, impl_item.impl_item_id());
- intravisit::walk_impl_item(self, impl_item);
- }
-}
-
-///////////////////////////////////////////////////////////////////////////
-// Utility types and common code for the above passes.
-
-fn bad_placeholder<'tcx>(
- tcx: TyCtxt<'tcx>,
- mut spans: Vec<Span>,
- kind: &'static str,
-) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
- let kind = if kind.ends_with('s') { format!("{}es", kind) } else { format!("{}s", kind) };
-
- spans.sort();
- let mut err = struct_span_err!(
- tcx.sess,
- spans.clone(),
- E0121,
- "the placeholder `_` is not allowed within types on item signatures for {}",
- kind
- );
- for span in spans {
- err.span_label(span, "not allowed in type signatures");
- }
- err
-}
-
-impl<'tcx> ItemCtxt<'tcx> {
- pub fn new(tcx: TyCtxt<'tcx>, item_def_id: DefId) -> ItemCtxt<'tcx> {
- ItemCtxt { tcx, item_def_id }
- }
-
- pub fn to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> {
- <dyn AstConv<'_>>::ast_ty_to_ty(self, ast_ty)
- }
-
- pub fn hir_id(&self) -> hir::HirId {
- self.tcx.hir().local_def_id_to_hir_id(self.item_def_id.expect_local())
- }
-
- pub fn node(&self) -> hir::Node<'tcx> {
- self.tcx.hir().get(self.hir_id())
- }
-}
-
-impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> {
- fn tcx(&self) -> TyCtxt<'tcx> {
- self.tcx
- }
-
- fn item_def_id(&self) -> Option<DefId> {
- Some(self.item_def_id)
- }
-
- fn get_type_parameter_bounds(
- &self,
- span: Span,
- def_id: DefId,
- assoc_name: Ident,
- ) -> ty::GenericPredicates<'tcx> {
- self.tcx.at(span).type_param_predicates((
- self.item_def_id,
- def_id.expect_local(),
- assoc_name,
- ))
- }
-
- fn re_infer(&self, _: Option<&ty::GenericParamDef>, _: Span) -> Option<ty::Region<'tcx>> {
- None
- }
-
- fn allow_ty_infer(&self) -> bool {
- false
- }
-
- fn ty_infer(&self, _: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx> {
- self.tcx().ty_error_with_message(span, "bad placeholder type")
- }
-
- fn ct_infer(&self, ty: Ty<'tcx>, _: Option<&ty::GenericParamDef>, span: Span) -> Const<'tcx> {
- let ty = self.tcx.fold_regions(ty, |r, _| match *r {
- ty::ReErased => self.tcx.lifetimes.re_static,
- _ => r,
- });
- self.tcx().const_error_with_message(ty, span, "bad placeholder constant")
- }
-
- fn projected_ty_from_poly_trait_ref(
- &self,
- span: Span,
- item_def_id: DefId,
- item_segment: &hir::PathSegment<'_>,
- poly_trait_ref: ty::PolyTraitRef<'tcx>,
- ) -> Ty<'tcx> {
- if let Some(trait_ref) = poly_trait_ref.no_bound_vars() {
- let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
- self,
- self.tcx,
- span,
- item_def_id,
- item_segment,
- trait_ref.substs,
- );
- self.tcx().mk_projection(item_def_id, item_substs)
- } else {
- // There are no late-bound regions; we can just ignore the binder.
- let mut err = struct_span_err!(
- self.tcx().sess,
- span,
- E0212,
- "cannot use the associated type of a trait \
- with uninferred generic parameters"
- );
-
- match self.node() {
- hir::Node::Field(_) | hir::Node::Ctor(_) | hir::Node::Variant(_) => {
- let item =
- self.tcx.hir().expect_item(self.tcx.hir().get_parent_item(self.hir_id()));
- match &item.kind {
- hir::ItemKind::Enum(_, generics)
- | hir::ItemKind::Struct(_, generics)
- | hir::ItemKind::Union(_, generics) => {
- let lt_name = get_new_lifetime_name(self.tcx, poly_trait_ref, generics);
- let (lt_sp, sugg) = match generics.params {
- [] => (generics.span, format!("<{}>", lt_name)),
- [bound, ..] => {
- (bound.span.shrink_to_lo(), format!("{}, ", lt_name))
- }
- };
- let suggestions = vec![
- (lt_sp, sugg),
- (
- span.with_hi(item_segment.ident.span.lo()),
- format!(
- "{}::",
- // Replace the existing lifetimes with a new named lifetime.
- self.tcx.replace_late_bound_regions_uncached(
- poly_trait_ref,
- |_| {
- self.tcx.mk_region(ty::ReEarlyBound(
- ty::EarlyBoundRegion {
- def_id: item_def_id,
- index: 0,
- name: Symbol::intern(<_name),
- },
- ))
- }
- ),
- ),
- ),
- ];
- err.multipart_suggestion(
- "use a fully qualified path with explicit lifetimes",
- suggestions,
- Applicability::MaybeIncorrect,
- );
- }
- _ => {}
- }
- }
- hir::Node::Item(hir::Item {
- kind:
- hir::ItemKind::Struct(..) | hir::ItemKind::Enum(..) | hir::ItemKind::Union(..),
- ..
- }) => {}
- hir::Node::Item(_)
- | hir::Node::ForeignItem(_)
- | hir::Node::TraitItem(_)
- | hir::Node::ImplItem(_) => {
- err.span_suggestion_verbose(
- span.with_hi(item_segment.ident.span.lo()),
- "use a fully qualified path with inferred lifetimes",
- format!(
- "{}::",
- // Erase named lt, we want `<A as B<'_>::C`, not `<A as B<'a>::C`.
- self.tcx.anonymize_late_bound_regions(poly_trait_ref).skip_binder(),
- ),
- Applicability::MaybeIncorrect,
- );
- }
- _ => {}
- }
- err.emit();
- self.tcx().ty_error()
- }
- }
-
- fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
- // Types in item signatures are not normalized to avoid undue dependencies.
- ty
- }
-
- fn set_tainted_by_errors(&self) {
- // There's no obvious place to track this, so just let it go.
- }
-
- fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
- // There's no place to record types from signatures?
- }
-}
-
-/// Synthesize a new lifetime name that doesn't clash with any of the lifetimes already present.
-fn get_new_lifetime_name<'tcx>(
- tcx: TyCtxt<'tcx>,
- poly_trait_ref: ty::PolyTraitRef<'tcx>,
- generics: &hir::Generics<'tcx>,
-) -> String {
- let existing_lifetimes = tcx
- .collect_referenced_late_bound_regions(&poly_trait_ref)
- .into_iter()
- .filter_map(|lt| {
- if let ty::BoundRegionKind::BrNamed(_, name) = lt {
- Some(name.as_str().to_string())
- } else {
- None
- }
- })
- .chain(generics.params.iter().filter_map(|param| {
- if let hir::GenericParamKind::Lifetime { .. } = ¶m.kind {
- Some(param.name.ident().as_str().to_string())
- } else {
- None
- }
- }))
- .collect::<FxHashSet<String>>();
-
- let a_to_z_repeat_n = |n| {
- (b'a'..=b'z').map(move |c| {
- let mut s = '\''.to_string();
- s.extend(std::iter::repeat(char::from(c)).take(n));
- s
- })
- };
-
- // If all single char lifetime names are present, we wrap around and double the chars.
- (1..).flat_map(a_to_z_repeat_n).find(|lt| !existing_lifetimes.contains(lt.as_str())).unwrap()
-}
-
-/// Returns the predicates defined on `item_def_id` of the form
-/// `X: Foo` where `X` is the type parameter `def_id`.
-#[instrument(level = "trace", skip(tcx))]
-fn type_param_predicates(
- tcx: TyCtxt<'_>,
- (item_def_id, def_id, assoc_name): (DefId, LocalDefId, Ident),
-) -> ty::GenericPredicates<'_> {
- use rustc_hir::*;
-
- // In the AST, bounds can derive from two places. Either
- // written inline like `<T: Foo>` or in a where-clause like
- // `where T: Foo`.
-
- let param_id = tcx.hir().local_def_id_to_hir_id(def_id);
- let param_owner = tcx.hir().ty_param_owner(def_id);
- let generics = tcx.generics_of(param_owner);
- let index = generics.param_def_id_to_index[&def_id.to_def_id()];
- let ty = tcx.mk_ty_param(index, tcx.hir().ty_param_name(def_id));
-
- // Don't look for bounds where the type parameter isn't in scope.
- let parent = if item_def_id == param_owner.to_def_id() {
- None
- } else {
- tcx.generics_of(item_def_id).parent
- };
-
- let mut result = parent
- .map(|parent| {
- let icx = ItemCtxt::new(tcx, parent);
- icx.get_type_parameter_bounds(DUMMY_SP, def_id.to_def_id(), assoc_name)
- })
- .unwrap_or_default();
- let mut extend = None;
-
- let item_hir_id = tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local());
- let ast_generics = match tcx.hir().get(item_hir_id) {
- Node::TraitItem(item) => &item.generics,
-
- Node::ImplItem(item) => &item.generics,
-
- Node::Item(item) => {
- match item.kind {
- ItemKind::Fn(.., ref generics, _)
- | ItemKind::Impl(hir::Impl { ref generics, .. })
- | ItemKind::TyAlias(_, ref generics)
- | ItemKind::OpaqueTy(OpaqueTy {
- ref generics,
- origin: hir::OpaqueTyOrigin::TyAlias,
- ..
- })
- | ItemKind::Enum(_, ref generics)
- | ItemKind::Struct(_, ref generics)
- | ItemKind::Union(_, ref generics) => generics,
- ItemKind::Trait(_, _, ref generics, ..) => {
- // Implied `Self: Trait` and supertrait bounds.
- if param_id == item_hir_id {
- let identity_trait_ref = ty::TraitRef::identity(tcx, item_def_id);
- extend =
- Some((identity_trait_ref.without_const().to_predicate(tcx), item.span));
- }
- generics
- }
- _ => return result,
- }
- }
-
- Node::ForeignItem(item) => match item.kind {
- ForeignItemKind::Fn(_, _, ref generics) => generics,
- _ => return result,
- },
-
- _ => return result,
- };
-
- let icx = ItemCtxt::new(tcx, item_def_id);
- let extra_predicates = extend.into_iter().chain(
- icx.type_parameter_bounds_in_generics(
- ast_generics,
- param_id,
- ty,
- OnlySelfBounds(true),
- Some(assoc_name),
- )
- .into_iter()
- .filter(|(predicate, _)| match predicate.kind().skip_binder() {
- ty::PredicateKind::Trait(data) => data.self_ty().is_param(index),
- _ => false,
- }),
- );
- result.predicates =
- tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(extra_predicates));
- result
-}
-
-impl<'tcx> ItemCtxt<'tcx> {
- /// Finds bounds from `hir::Generics`. This requires scanning through the
- /// AST. We do this to avoid having to convert *all* the bounds, which
- /// would create artificial cycles. Instead, we can only convert the
- /// bounds for a type parameter `X` if `X::Foo` is used.
- #[instrument(level = "trace", skip(self, ast_generics))]
- fn type_parameter_bounds_in_generics(
- &self,
- ast_generics: &'tcx hir::Generics<'tcx>,
- param_id: hir::HirId,
- ty: Ty<'tcx>,
- only_self_bounds: OnlySelfBounds,
- assoc_name: Option<Ident>,
- ) -> Vec<(ty::Predicate<'tcx>, Span)> {
- let param_def_id = self.tcx.hir().local_def_id(param_id).to_def_id();
- trace!(?param_def_id);
- ast_generics
- .predicates
- .iter()
- .filter_map(|wp| match *wp {
- hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
- _ => None,
- })
- .flat_map(|bp| {
- let bt = if bp.is_param_bound(param_def_id) {
- Some(ty)
- } else if !only_self_bounds.0 {
- Some(self.to_ty(bp.bounded_ty))
- } else {
- None
- };
- let bvars = self.tcx.late_bound_vars(bp.bounded_ty.hir_id);
-
- bp.bounds.iter().filter_map(move |b| bt.map(|bt| (bt, b, bvars))).filter(
- |(_, b, _)| match assoc_name {
- Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
- None => true,
- },
- )
- })
- .flat_map(|(bt, b, bvars)| predicates_from_bound(self, bt, b, bvars))
- .collect()
- }
-
- #[instrument(level = "trace", skip(self))]
- fn bound_defines_assoc_item(&self, b: &hir::GenericBound<'_>, assoc_name: Ident) -> bool {
- match b {
- hir::GenericBound::Trait(poly_trait_ref, _) => {
- let trait_ref = &poly_trait_ref.trait_ref;
- if let Some(trait_did) = trait_ref.trait_def_id() {
- self.tcx.trait_may_define_assoc_type(trait_did, assoc_name)
- } else {
- false
- }
- }
- _ => false,
- }
- }
-}
-
-fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
- let it = tcx.hir().item(item_id);
- debug!("convert: item {} with id {}", it.ident, it.hir_id());
- let def_id = item_id.def_id;
-
- match it.kind {
- // These don't define types.
- hir::ItemKind::ExternCrate(_)
- | hir::ItemKind::Use(..)
- | hir::ItemKind::Macro(..)
- | hir::ItemKind::Mod(_)
- | hir::ItemKind::GlobalAsm(_) => {}
- hir::ItemKind::ForeignMod { items, .. } => {
- for item in items {
- let item = tcx.hir().foreign_item(item.id);
- tcx.ensure().generics_of(item.def_id);
- tcx.ensure().type_of(item.def_id);
- tcx.ensure().predicates_of(item.def_id);
- match item.kind {
- hir::ForeignItemKind::Fn(..) => tcx.ensure().fn_sig(item.def_id),
- hir::ForeignItemKind::Static(..) => {
- let mut visitor = HirPlaceholderCollector::default();
- visitor.visit_foreign_item(item);
- placeholder_type_error(
- tcx,
- None,
- visitor.0,
- false,
- None,
- "static variable",
- );
- }
- _ => (),
- }
- }
- }
- hir::ItemKind::Enum(ref enum_definition, _) => {
- tcx.ensure().generics_of(def_id);
- tcx.ensure().type_of(def_id);
- tcx.ensure().predicates_of(def_id);
- convert_enum_variant_types(tcx, def_id.to_def_id(), enum_definition.variants);
- }
- hir::ItemKind::Impl { .. } => {
- tcx.ensure().generics_of(def_id);
- tcx.ensure().type_of(def_id);
- tcx.ensure().impl_trait_ref(def_id);
- tcx.ensure().predicates_of(def_id);
- }
- hir::ItemKind::Trait(..) => {
- tcx.ensure().generics_of(def_id);
- tcx.ensure().trait_def(def_id);
- tcx.at(it.span).super_predicates_of(def_id);
- tcx.ensure().predicates_of(def_id);
- }
- hir::ItemKind::TraitAlias(..) => {
- tcx.ensure().generics_of(def_id);
- tcx.at(it.span).super_predicates_of(def_id);
- tcx.ensure().predicates_of(def_id);
- }
- hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref struct_def, _) => {
- tcx.ensure().generics_of(def_id);
- tcx.ensure().type_of(def_id);
- tcx.ensure().predicates_of(def_id);
-
- for f in struct_def.fields() {
- let def_id = tcx.hir().local_def_id(f.hir_id);
- tcx.ensure().generics_of(def_id);
- tcx.ensure().type_of(def_id);
- tcx.ensure().predicates_of(def_id);
- }
-
- if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
- convert_variant_ctor(tcx, ctor_hir_id);
- }
- }
-
- // Desugared from `impl Trait`, so visited by the function's return type.
- hir::ItemKind::OpaqueTy(hir::OpaqueTy {
- origin: hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..),
- ..
- }) => {}
-
- // Don't call `type_of` on opaque types, since that depends on type
- // checking function bodies. `check_item_type` ensures that it's called
- // instead.
- hir::ItemKind::OpaqueTy(..) => {
- tcx.ensure().generics_of(def_id);
- tcx.ensure().predicates_of(def_id);
- tcx.ensure().explicit_item_bounds(def_id);
- }
- hir::ItemKind::TyAlias(..)
- | hir::ItemKind::Static(..)
- | hir::ItemKind::Const(..)
- | hir::ItemKind::Fn(..) => {
- tcx.ensure().generics_of(def_id);
- tcx.ensure().type_of(def_id);
- tcx.ensure().predicates_of(def_id);
- match it.kind {
- hir::ItemKind::Fn(..) => tcx.ensure().fn_sig(def_id),
- hir::ItemKind::OpaqueTy(..) => tcx.ensure().item_bounds(def_id),
- hir::ItemKind::Const(ty, ..) | hir::ItemKind::Static(ty, ..) => {
- if !is_suggestable_infer_ty(ty) {
- let mut visitor = HirPlaceholderCollector::default();
- visitor.visit_item(it);
- placeholder_type_error(tcx, None, visitor.0, false, None, it.kind.descr());
- }
- }
- _ => (),
- }
- }
- }
-}
-
-fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
- let trait_item = tcx.hir().trait_item(trait_item_id);
- tcx.ensure().generics_of(trait_item_id.def_id);
-
- match trait_item.kind {
- hir::TraitItemKind::Fn(..) => {
- tcx.ensure().type_of(trait_item_id.def_id);
- tcx.ensure().fn_sig(trait_item_id.def_id);
- }
-
- hir::TraitItemKind::Const(.., Some(_)) => {
- tcx.ensure().type_of(trait_item_id.def_id);
- }
-
- hir::TraitItemKind::Const(hir_ty, _) => {
- tcx.ensure().type_of(trait_item_id.def_id);
- // Account for `const C: _;`.
- let mut visitor = HirPlaceholderCollector::default();
- visitor.visit_trait_item(trait_item);
- if !tcx.sess.diagnostic().has_stashed_diagnostic(hir_ty.span, StashKey::ItemNoType) {
- placeholder_type_error(tcx, None, visitor.0, false, None, "constant");
- }
- }
-
- hir::TraitItemKind::Type(_, Some(_)) => {
- tcx.ensure().item_bounds(trait_item_id.def_id);
- tcx.ensure().type_of(trait_item_id.def_id);
- // Account for `type T = _;`.
- let mut visitor = HirPlaceholderCollector::default();
- visitor.visit_trait_item(trait_item);
- placeholder_type_error(tcx, None, visitor.0, false, None, "associated type");
- }
-
- hir::TraitItemKind::Type(_, None) => {
- tcx.ensure().item_bounds(trait_item_id.def_id);
- // #74612: Visit and try to find bad placeholders
- // even if there is no concrete type.
- let mut visitor = HirPlaceholderCollector::default();
- visitor.visit_trait_item(trait_item);
-
- placeholder_type_error(tcx, None, visitor.0, false, None, "associated type");
- }
- };
-
- tcx.ensure().predicates_of(trait_item_id.def_id);
-}
-
-fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) {
- let def_id = impl_item_id.def_id;
- tcx.ensure().generics_of(def_id);
- tcx.ensure().type_of(def_id);
- tcx.ensure().predicates_of(def_id);
- let impl_item = tcx.hir().impl_item(impl_item_id);
- match impl_item.kind {
- hir::ImplItemKind::Fn(..) => {
- tcx.ensure().fn_sig(def_id);
- }
- hir::ImplItemKind::TyAlias(_) => {
- // Account for `type T = _;`
- let mut visitor = HirPlaceholderCollector::default();
- visitor.visit_impl_item(impl_item);
-
- placeholder_type_error(tcx, None, visitor.0, false, None, "associated type");
- }
- hir::ImplItemKind::Const(..) => {}
- }
-}
-
-fn convert_variant_ctor(tcx: TyCtxt<'_>, ctor_id: hir::HirId) {
- let def_id = tcx.hir().local_def_id(ctor_id);
- tcx.ensure().generics_of(def_id);
- tcx.ensure().type_of(def_id);
- tcx.ensure().predicates_of(def_id);
-}
-
-fn convert_enum_variant_types(tcx: TyCtxt<'_>, def_id: DefId, variants: &[hir::Variant<'_>]) {
- let def = tcx.adt_def(def_id);
- let repr_type = def.repr().discr_type();
- let initial = repr_type.initial_discriminant(tcx);
- let mut prev_discr = None::<Discr<'_>>;
-
- // fill the discriminant values and field types
- for variant in variants {
- let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
- prev_discr = Some(
- if let Some(ref e) = variant.disr_expr {
- let expr_did = tcx.hir().local_def_id(e.hir_id);
- def.eval_explicit_discr(tcx, expr_did.to_def_id())
- } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) {
- Some(discr)
- } else {
- struct_span_err!(tcx.sess, variant.span, E0370, "enum discriminant overflowed")
- .span_label(
- variant.span,
- format!("overflowed on value after {}", prev_discr.unwrap()),
- )
- .note(&format!(
- "explicitly set `{} = {}` if that is desired outcome",
- variant.ident, wrapped_discr
- ))
- .emit();
- None
- }
- .unwrap_or(wrapped_discr),
- );
-
- for f in variant.data.fields() {
- let def_id = tcx.hir().local_def_id(f.hir_id);
- tcx.ensure().generics_of(def_id);
- tcx.ensure().type_of(def_id);
- tcx.ensure().predicates_of(def_id);
- }
-
- // Convert the ctor, if any. This also registers the variant as
- // an item.
- if let Some(ctor_hir_id) = variant.data.ctor_hir_id() {
- convert_variant_ctor(tcx, ctor_hir_id);
- }
- }
-}
-
-fn convert_variant(
- tcx: TyCtxt<'_>,
- variant_did: Option<LocalDefId>,
- ctor_did: Option<LocalDefId>,
- ident: Ident,
- discr: ty::VariantDiscr,
- def: &hir::VariantData<'_>,
- adt_kind: ty::AdtKind,
- parent_did: LocalDefId,
-) -> ty::VariantDef {
- let mut seen_fields: FxHashMap<Ident, Span> = Default::default();
- let fields = def
- .fields()
- .iter()
- .map(|f| {
- let fid = tcx.hir().local_def_id(f.hir_id);
- let dup_span = seen_fields.get(&f.ident.normalize_to_macros_2_0()).cloned();
- if let Some(prev_span) = dup_span {
- tcx.sess.emit_err(errors::FieldAlreadyDeclared {
- field_name: f.ident,
- span: f.span,
- prev_span,
- });
- } else {
- seen_fields.insert(f.ident.normalize_to_macros_2_0(), f.span);
- }
-
- ty::FieldDef { did: fid.to_def_id(), name: f.ident.name, vis: tcx.visibility(fid) }
- })
- .collect();
- let recovered = match def {
- hir::VariantData::Struct(_, r) => *r,
- _ => false,
- };
- ty::VariantDef::new(
- ident.name,
- variant_did.map(LocalDefId::to_def_id),
- ctor_did.map(LocalDefId::to_def_id),
- discr,
- fields,
- CtorKind::from_hir(def),
- adt_kind,
- parent_did.to_def_id(),
- recovered,
- adt_kind == AdtKind::Struct && tcx.has_attr(parent_did.to_def_id(), sym::non_exhaustive)
- || variant_did.map_or(false, |variant_did| {
- tcx.has_attr(variant_did.to_def_id(), sym::non_exhaustive)
- }),
- )
-}
-
-fn adt_def<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> ty::AdtDef<'tcx> {
- use rustc_hir::*;
-
- let def_id = def_id.expect_local();
- let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
- let Node::Item(item) = tcx.hir().get(hir_id) else {
- bug!();
- };
-
- let repr = ReprOptions::new(tcx, def_id.to_def_id());
- let (kind, variants) = match item.kind {
- ItemKind::Enum(ref def, _) => {
- let mut distance_from_explicit = 0;
- let variants = def
- .variants
- .iter()
- .map(|v| {
- let variant_did = Some(tcx.hir().local_def_id(v.id));
- let ctor_did =
- v.data.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
-
- let discr = if let Some(ref e) = v.disr_expr {
- distance_from_explicit = 0;
- ty::VariantDiscr::Explicit(tcx.hir().local_def_id(e.hir_id).to_def_id())
- } else {
- ty::VariantDiscr::Relative(distance_from_explicit)
- };
- distance_from_explicit += 1;
-
- convert_variant(
- tcx,
- variant_did,
- ctor_did,
- v.ident,
- discr,
- &v.data,
- AdtKind::Enum,
- def_id,
- )
- })
- .collect();
-
- (AdtKind::Enum, variants)
- }
- ItemKind::Struct(ref def, _) => {
- let variant_did = None::<LocalDefId>;
- let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
-
- let variants = std::iter::once(convert_variant(
- tcx,
- variant_did,
- ctor_did,
- item.ident,
- ty::VariantDiscr::Relative(0),
- def,
- AdtKind::Struct,
- def_id,
- ))
- .collect();
-
- (AdtKind::Struct, variants)
- }
- ItemKind::Union(ref def, _) => {
- let variant_did = None;
- let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
-
- let variants = std::iter::once(convert_variant(
- tcx,
- variant_did,
- ctor_did,
- item.ident,
- ty::VariantDiscr::Relative(0),
- def,
- AdtKind::Union,
- def_id,
- ))
- .collect();
-
- (AdtKind::Union, variants)
- }
- _ => bug!(),
- };
- tcx.alloc_adt_def(def_id.to_def_id(), kind, variants, repr)
-}
-
-/// Ensures that the super-predicates of the trait with a `DefId`
-/// of `trait_def_id` are converted and stored. This also ensures that
-/// the transitive super-predicates are converted.
-fn super_predicates_of(tcx: TyCtxt<'_>, trait_def_id: DefId) -> ty::GenericPredicates<'_> {
- debug!("super_predicates(trait_def_id={:?})", trait_def_id);
- tcx.super_predicates_that_define_assoc_type((trait_def_id, None))
-}
-
-/// Ensures that the super-predicates of the trait with a `DefId`
-/// of `trait_def_id` are converted and stored. This also ensures that
-/// the transitive super-predicates are converted.
-fn super_predicates_that_define_assoc_type(
- tcx: TyCtxt<'_>,
- (trait_def_id, assoc_name): (DefId, Option<Ident>),
-) -> ty::GenericPredicates<'_> {
- debug!(
- "super_predicates_that_define_assoc_type(trait_def_id={:?}, assoc_name={:?})",
- trait_def_id, assoc_name
- );
- if trait_def_id.is_local() {
- debug!("super_predicates_that_define_assoc_type: local trait_def_id={:?}", trait_def_id);
- let trait_hir_id = tcx.hir().local_def_id_to_hir_id(trait_def_id.expect_local());
-
- let Node::Item(item) = tcx.hir().get(trait_hir_id) else {
- bug!("trait_node_id {} is not an item", trait_hir_id);
- };
-
- let (generics, bounds) = match item.kind {
- hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits),
- hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits),
- _ => span_bug!(item.span, "super_predicates invoked on non-trait"),
- };
-
- let icx = ItemCtxt::new(tcx, trait_def_id);
-
- // Convert the bounds that follow the colon, e.g., `Bar + Zed` in `trait Foo: Bar + Zed`.
- let self_param_ty = tcx.types.self_param;
- let superbounds1 = if let Some(assoc_name) = assoc_name {
- <dyn AstConv<'_>>::compute_bounds_that_match_assoc_type(
- &icx,
- self_param_ty,
- bounds,
- assoc_name,
- )
- } else {
- <dyn AstConv<'_>>::compute_bounds(&icx, self_param_ty, bounds)
- };
-
- let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
-
- // Convert any explicit superbounds in the where-clause,
- // e.g., `trait Foo where Self: Bar`.
- // In the case of trait aliases, however, we include all bounds in the where-clause,
- // so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>`
- // as one of its "superpredicates".
- let is_trait_alias = tcx.is_trait_alias(trait_def_id);
- let superbounds2 = icx.type_parameter_bounds_in_generics(
- generics,
- item.hir_id(),
- self_param_ty,
- OnlySelfBounds(!is_trait_alias),
- assoc_name,
- );
-
- // Combine the two lists to form the complete set of superbounds:
- let superbounds = &*tcx.arena.alloc_from_iter(superbounds1.into_iter().chain(superbounds2));
- debug!(?superbounds);
-
- // Now require that immediate supertraits are converted,
- // which will, in turn, reach indirect supertraits.
- if assoc_name.is_none() {
- // Now require that immediate supertraits are converted,
- // which will, in turn, reach indirect supertraits.
- for &(pred, span) in superbounds {
- debug!("superbound: {:?}", pred);
- if let ty::PredicateKind::Trait(bound) = pred.kind().skip_binder() {
- tcx.at(span).super_predicates_of(bound.def_id());
- }
- }
- }
-
- ty::GenericPredicates { parent: None, predicates: superbounds }
- } else {
- // if `assoc_name` is None, then the query should've been redirected to an
- // external provider
- assert!(assoc_name.is_some());
- tcx.super_predicates_of(trait_def_id)
- }
-}
-
-fn trait_def(tcx: TyCtxt<'_>, def_id: DefId) -> ty::TraitDef {
- let item = tcx.hir().expect_item(def_id.expect_local());
-
- let (is_auto, unsafety, items) = match item.kind {
- hir::ItemKind::Trait(is_auto, unsafety, .., items) => {
- (is_auto == hir::IsAuto::Yes, unsafety, items)
- }
- hir::ItemKind::TraitAlias(..) => (false, hir::Unsafety::Normal, &[][..]),
- _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
- };
-
- let paren_sugar = tcx.has_attr(def_id, sym::rustc_paren_sugar);
- if paren_sugar && !tcx.features().unboxed_closures {
- tcx.sess
- .struct_span_err(
- item.span,
- "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
- which traits can use parenthetical notation",
- )
- .help("add `#![feature(unboxed_closures)]` to the crate attributes to use it")
- .emit();
- }
-
- let is_marker = tcx.has_attr(def_id, sym::marker);
- let skip_array_during_method_dispatch =
- tcx.has_attr(def_id, sym::rustc_skip_array_during_method_dispatch);
- let spec_kind = if tcx.has_attr(def_id, sym::rustc_unsafe_specialization_marker) {
- ty::trait_def::TraitSpecializationKind::Marker
- } else if tcx.has_attr(def_id, sym::rustc_specialization_trait) {
- ty::trait_def::TraitSpecializationKind::AlwaysApplicable
- } else {
- ty::trait_def::TraitSpecializationKind::None
- };
- let must_implement_one_of = tcx
- .get_attr(def_id, sym::rustc_must_implement_one_of)
- // Check that there are at least 2 arguments of `#[rustc_must_implement_one_of]`
- // and that they are all identifiers
- .and_then(|attr| match attr.meta_item_list() {
- Some(items) if items.len() < 2 => {
- tcx.sess
- .struct_span_err(
- attr.span,
- "the `#[rustc_must_implement_one_of]` attribute must be \
- used with at least 2 args",
- )
- .emit();
-
- None
- }
- Some(items) => items
- .into_iter()
- .map(|item| item.ident().ok_or(item.span()))
- .collect::<Result<Box<[_]>, _>>()
- .map_err(|span| {
- tcx.sess
- .struct_span_err(span, "must be a name of an associated function")
- .emit();
- })
- .ok()
- .zip(Some(attr.span)),
- // Error is reported by `rustc_attr!`
- None => None,
- })
- // Check that all arguments of `#[rustc_must_implement_one_of]` reference
- // functions in the trait with default implementations
- .and_then(|(list, attr_span)| {
- let errors = list.iter().filter_map(|ident| {
- let item = items.iter().find(|item| item.ident == *ident);
-
- match item {
- Some(item) if matches!(item.kind, hir::AssocItemKind::Fn { .. }) => {
- if !tcx.impl_defaultness(item.id.def_id).has_value() {
- tcx.sess
- .struct_span_err(
- item.span,
- "This function doesn't have a default implementation",
- )
- .span_note(attr_span, "required by this annotation")
- .emit();
-
- return Some(());
- }
-
- return None;
- }
- Some(item) => {
- tcx.sess
- .struct_span_err(item.span, "Not a function")
- .span_note(attr_span, "required by this annotation")
- .note(
- "All `#[rustc_must_implement_one_of]` arguments \
- must be associated function names",
- )
- .emit();
- }
- None => {
- tcx.sess
- .struct_span_err(ident.span, "Function not found in this trait")
- .emit();
- }
- }
-
- Some(())
- });
-
- (errors.count() == 0).then_some(list)
- })
- // Check for duplicates
- .and_then(|list| {
- let mut set: FxHashMap<Symbol, Span> = FxHashMap::default();
- let mut no_dups = true;
-
- for ident in &*list {
- if let Some(dup) = set.insert(ident.name, ident.span) {
- tcx.sess
- .struct_span_err(vec![dup, ident.span], "Functions names are duplicated")
- .note(
- "All `#[rustc_must_implement_one_of]` arguments \
- must be unique",
- )
- .emit();
-
- no_dups = false;
- }
- }
-
- no_dups.then_some(list)
- });
-
- ty::TraitDef::new(
- def_id,
- unsafety,
- paren_sugar,
- is_auto,
- is_marker,
- skip_array_during_method_dispatch,
- spec_kind,
- must_implement_one_of,
- )
-}
-
-fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<Span> {
- struct LateBoundRegionsDetector<'tcx> {
- tcx: TyCtxt<'tcx>,
- outer_index: ty::DebruijnIndex,
- has_late_bound_regions: Option<Span>,
- }
-
- impl<'tcx> Visitor<'tcx> for LateBoundRegionsDetector<'tcx> {
- fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
- if self.has_late_bound_regions.is_some() {
- return;
- }
- match ty.kind {
- hir::TyKind::BareFn(..) => {
- self.outer_index.shift_in(1);
- intravisit::walk_ty(self, ty);
- self.outer_index.shift_out(1);
- }
- _ => intravisit::walk_ty(self, ty),
- }
- }
-
- fn visit_poly_trait_ref(&mut self, tr: &'tcx hir::PolyTraitRef<'tcx>) {
- if self.has_late_bound_regions.is_some() {
- return;
- }
- self.outer_index.shift_in(1);
- intravisit::walk_poly_trait_ref(self, tr);
- self.outer_index.shift_out(1);
- }
-
- fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
- if self.has_late_bound_regions.is_some() {
- return;
- }
-
- match self.tcx.named_region(lt.hir_id) {
- Some(rl::Region::Static | rl::Region::EarlyBound(..)) => {}
- Some(rl::Region::LateBound(debruijn, _, _)) if debruijn < self.outer_index => {}
- Some(rl::Region::LateBound(..) | rl::Region::Free(..)) | None => {
- self.has_late_bound_regions = Some(lt.span);
- }
- }
- }
- }
-
- fn has_late_bound_regions<'tcx>(
- tcx: TyCtxt<'tcx>,
- generics: &'tcx hir::Generics<'tcx>,
- decl: &'tcx hir::FnDecl<'tcx>,
- ) -> Option<Span> {
- let mut visitor = LateBoundRegionsDetector {
- tcx,
- outer_index: ty::INNERMOST,
- has_late_bound_regions: None,
- };
- for param in generics.params {
- if let GenericParamKind::Lifetime { .. } = param.kind {
- if tcx.is_late_bound(param.hir_id) {
- return Some(param.span);
- }
- }
- }
- visitor.visit_fn_decl(decl);
- visitor.has_late_bound_regions
- }
-
- match node {
- Node::TraitItem(item) => match item.kind {
- hir::TraitItemKind::Fn(ref sig, _) => {
- has_late_bound_regions(tcx, &item.generics, sig.decl)
- }
- _ => None,
- },
- Node::ImplItem(item) => match item.kind {
- hir::ImplItemKind::Fn(ref sig, _) => {
- has_late_bound_regions(tcx, &item.generics, sig.decl)
- }
- _ => None,
- },
- Node::ForeignItem(item) => match item.kind {
- hir::ForeignItemKind::Fn(fn_decl, _, ref generics) => {
- has_late_bound_regions(tcx, generics, fn_decl)
- }
- _ => None,
- },
- Node::Item(item) => match item.kind {
- hir::ItemKind::Fn(ref sig, .., ref generics, _) => {
- has_late_bound_regions(tcx, generics, sig.decl)
- }
- _ => None,
- },
- _ => None,
- }
-}
-
-struct AnonConstInParamTyDetector {
- in_param_ty: bool,
- found_anon_const_in_param_ty: bool,
- ct: HirId,
-}
-
-impl<'v> Visitor<'v> for AnonConstInParamTyDetector {
- fn visit_generic_param(&mut self, p: &'v hir::GenericParam<'v>) {
- if let GenericParamKind::Const { ty, default: _ } = p.kind {
- let prev = self.in_param_ty;
- self.in_param_ty = true;
- self.visit_ty(ty);
- self.in_param_ty = prev;
- }
- }
-
- fn visit_anon_const(&mut self, c: &'v hir::AnonConst) {
- if self.in_param_ty && self.ct == c.hir_id {
- self.found_anon_const_in_param_ty = true;
- } else {
- intravisit::walk_anon_const(self, c)
- }
- }
-}
-
-fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
- use rustc_hir::*;
-
- let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
-
- let node = tcx.hir().get(hir_id);
- let parent_def_id = match node {
- Node::ImplItem(_)
- | Node::TraitItem(_)
- | Node::Variant(_)
- | Node::Ctor(..)
- | Node::Field(_) => {
- let parent_id = tcx.hir().get_parent_item(hir_id);
- Some(parent_id.to_def_id())
- }
- // FIXME(#43408) always enable this once `lazy_normalization` is
- // stable enough and does not need a feature gate anymore.
- Node::AnonConst(_) => {
- let parent_def_id = tcx.hir().get_parent_item(hir_id);
-
- let mut in_param_ty = false;
- for (_parent, node) in tcx.hir().parent_iter(hir_id) {
- if let Some(generics) = node.generics() {
- let mut visitor = AnonConstInParamTyDetector {
- in_param_ty: false,
- found_anon_const_in_param_ty: false,
- ct: hir_id,
- };
-
- visitor.visit_generics(generics);
- in_param_ty = visitor.found_anon_const_in_param_ty;
- break;
- }
- }
-
- if in_param_ty {
- // We do not allow generic parameters in anon consts if we are inside
- // of a const parameter type, e.g. `struct Foo<const N: usize, const M: [u8; N]>` is not allowed.
- None
- } else if tcx.lazy_normalization() {
- if let Some(param_id) = tcx.hir().opt_const_param_default_param_hir_id(hir_id) {
- // If the def_id we are calling generics_of on is an anon ct default i.e:
- //
- // struct Foo<const N: usize = { .. }>;
- // ^^^ ^ ^^^^^^ def id of this anon const
- // ^ ^ param_id
- // ^ parent_def_id
- //
- // then we only want to return generics for params to the left of `N`. If we don't do that we
- // end up with that const looking like: `ty::ConstKind::Unevaluated(def_id, substs: [N#0])`.
- //
- // This causes ICEs (#86580) when building the substs for Foo in `fn foo() -> Foo { .. }` as
- // we substitute the defaults with the partially built substs when we build the substs. Subst'ing
- // the `N#0` on the unevaluated const indexes into the empty substs we're in the process of building.
- //
- // We fix this by having this function return the parent's generics ourselves and truncating the
- // generics to only include non-forward declared params (with the exception of the `Self` ty)
- //
- // For the above code example that means we want `substs: []`
- // For the following struct def we want `substs: [N#0]` when generics_of is called on
- // the def id of the `{ N + 1 }` anon const
- // struct Foo<const N: usize, const M: usize = { N + 1 }>;
- //
- // This has some implications for how we get the predicates available to the anon const
- // see `explicit_predicates_of` for more information on this
- let generics = tcx.generics_of(parent_def_id.to_def_id());
- let param_def = tcx.hir().local_def_id(param_id).to_def_id();
- let param_def_idx = generics.param_def_id_to_index[¶m_def];
- // In the above example this would be .params[..N#0]
- let params = generics.params[..param_def_idx as usize].to_owned();
- let param_def_id_to_index =
- params.iter().map(|param| (param.def_id, param.index)).collect();
-
- return ty::Generics {
- // we set the parent of these generics to be our parent's parent so that we
- // dont end up with substs: [N, M, N] for the const default on a struct like this:
- // struct Foo<const N: usize, const M: usize = { ... }>;
- parent: generics.parent,
- parent_count: generics.parent_count,
- params,
- param_def_id_to_index,
- has_self: generics.has_self,
- has_late_bound_regions: generics.has_late_bound_regions,
- };
- }
-
- // HACK(eddyb) this provides the correct generics when
- // `feature(generic_const_expressions)` is enabled, so that const expressions
- // used with const generics, e.g. `Foo<{N+1}>`, can work at all.
- //
- // Note that we do not supply the parent generics when using
- // `min_const_generics`.
- Some(parent_def_id.to_def_id())
- } else {
- let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id));
- match parent_node {
- // HACK(eddyb) this provides the correct generics for repeat
- // expressions' count (i.e. `N` in `[x; N]`), and explicit
- // `enum` discriminants (i.e. `D` in `enum Foo { Bar = D }`),
- // as they shouldn't be able to cause query cycle errors.
- Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. })
- if constant.hir_id() == hir_id =>
- {
- Some(parent_def_id.to_def_id())
- }
- Node::Variant(Variant { disr_expr: Some(ref constant), .. })
- if constant.hir_id == hir_id =>
- {
- Some(parent_def_id.to_def_id())
- }
- Node::Expr(&Expr { kind: ExprKind::ConstBlock(_), .. }) => {
- Some(tcx.typeck_root_def_id(def_id))
- }
- // Exclude `GlobalAsm` here which cannot have generics.
- Node::Expr(&Expr { kind: ExprKind::InlineAsm(asm), .. })
- if asm.operands.iter().any(|(op, _op_sp)| match op {
- hir::InlineAsmOperand::Const { anon_const }
- | hir::InlineAsmOperand::SymFn { anon_const } => {
- anon_const.hir_id == hir_id
- }
- _ => false,
- }) =>
- {
- Some(parent_def_id.to_def_id())
- }
- _ => None,
- }
- }
- }
- Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure { .. }, .. }) => {
- Some(tcx.typeck_root_def_id(def_id))
- }
- Node::Item(item) => match item.kind {
- ItemKind::OpaqueTy(hir::OpaqueTy {
- origin:
- hir::OpaqueTyOrigin::FnReturn(fn_def_id) | hir::OpaqueTyOrigin::AsyncFn(fn_def_id),
- in_trait,
- ..
- }) => {
- if in_trait {
- assert!(matches!(tcx.def_kind(fn_def_id), DefKind::AssocFn))
- } else {
- assert!(matches!(tcx.def_kind(fn_def_id), DefKind::AssocFn | DefKind::Fn))
- }
- Some(fn_def_id.to_def_id())
- }
- ItemKind::OpaqueTy(hir::OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => {
- let parent_id = tcx.hir().get_parent_item(hir_id);
- assert_ne!(parent_id, CRATE_DEF_ID);
- debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id);
- // Opaque types are always nested within another item, and
- // inherit the generics of the item.
- Some(parent_id.to_def_id())
- }
- _ => None,
- },
- _ => None,
- };
-
- enum Defaults {
- Allowed,
- // See #36887
- FutureCompatDisallowed,
- Deny,
- }
-
- let no_generics = hir::Generics::empty();
- let ast_generics = node.generics().unwrap_or(&no_generics);
- let (opt_self, allow_defaults) = match node {
- Node::Item(item) => {
- match item.kind {
- ItemKind::Trait(..) | ItemKind::TraitAlias(..) => {
- // Add in the self type parameter.
- //
- // Something of a hack: use the node id for the trait, also as
- // the node id for the Self type parameter.
- let opt_self = Some(ty::GenericParamDef {
- index: 0,
- name: kw::SelfUpper,
- def_id,
- pure_wrt_drop: false,
- kind: ty::GenericParamDefKind::Type {
- has_default: false,
- synthetic: false,
- },
- });
-
- (opt_self, Defaults::Allowed)
- }
- ItemKind::TyAlias(..)
- | ItemKind::Enum(..)
- | ItemKind::Struct(..)
- | ItemKind::OpaqueTy(..)
- | ItemKind::Union(..) => (None, Defaults::Allowed),
- _ => (None, Defaults::FutureCompatDisallowed),
- }
- }
-
- // GATs
- Node::TraitItem(item) if matches!(item.kind, TraitItemKind::Type(..)) => {
- (None, Defaults::Deny)
- }
- Node::ImplItem(item) if matches!(item.kind, ImplItemKind::TyAlias(..)) => {
- (None, Defaults::Deny)
- }
-
- _ => (None, Defaults::FutureCompatDisallowed),
- };
-
- let has_self = opt_self.is_some();
- let mut parent_has_self = false;
- let mut own_start = has_self as u32;
- let parent_count = parent_def_id.map_or(0, |def_id| {
- let generics = tcx.generics_of(def_id);
- assert!(!has_self);
- parent_has_self = generics.has_self;
- own_start = generics.count() as u32;
- generics.parent_count + generics.params.len()
- });
-
- let mut params: Vec<_> = Vec::with_capacity(ast_generics.params.len() + has_self as usize);
-
- if let Some(opt_self) = opt_self {
- params.push(opt_self);
- }
-
- let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics);
- params.extend(early_lifetimes.enumerate().map(|(i, param)| ty::GenericParamDef {
- name: param.name.ident().name,
- index: own_start + i as u32,
- def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
- pure_wrt_drop: param.pure_wrt_drop,
- kind: ty::GenericParamDefKind::Lifetime,
- }));
-
- // Now create the real type and const parameters.
- let type_start = own_start - has_self as u32 + params.len() as u32;
- let mut i = 0;
-
- const TYPE_DEFAULT_NOT_ALLOWED: &'static str = "defaults for type parameters are only allowed in \
- `struct`, `enum`, `type`, or `trait` definitions";
-
- params.extend(ast_generics.params.iter().filter_map(|param| match param.kind {
- GenericParamKind::Lifetime { .. } => None,
- GenericParamKind::Type { ref default, synthetic, .. } => {
- if default.is_some() {
- match allow_defaults {
- Defaults::Allowed => {}
- Defaults::FutureCompatDisallowed
- if tcx.features().default_type_parameter_fallback => {}
- Defaults::FutureCompatDisallowed => {
- tcx.struct_span_lint_hir(
- lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
- param.hir_id,
- param.span,
- |lint| {
- lint.build(TYPE_DEFAULT_NOT_ALLOWED).emit();
- },
- );
- }
- Defaults::Deny => {
- tcx.sess.span_err(param.span, TYPE_DEFAULT_NOT_ALLOWED);
- }
- }
- }
-
- let kind = ty::GenericParamDefKind::Type { has_default: default.is_some(), synthetic };
-
- let param_def = ty::GenericParamDef {
- index: type_start + i as u32,
- name: param.name.ident().name,
- def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
- pure_wrt_drop: param.pure_wrt_drop,
- kind,
- };
- i += 1;
- Some(param_def)
- }
- GenericParamKind::Const { default, .. } => {
- if !matches!(allow_defaults, Defaults::Allowed) && default.is_some() {
- tcx.sess.span_err(
- param.span,
- "defaults for const parameters are only allowed in \
- `struct`, `enum`, `type`, or `trait` definitions",
- );
- }
-
- let param_def = ty::GenericParamDef {
- index: type_start + i as u32,
- name: param.name.ident().name,
- def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
- pure_wrt_drop: param.pure_wrt_drop,
- kind: ty::GenericParamDefKind::Const { has_default: default.is_some() },
- };
- i += 1;
- Some(param_def)
- }
- }));
-
- // provide junk type parameter defs - the only place that
- // cares about anything but the length is instantiation,
- // and we don't do that for closures.
- if let Node::Expr(&hir::Expr {
- kind: hir::ExprKind::Closure(hir::Closure { movability: gen, .. }),
- ..
- }) = node
- {
- let dummy_args = if gen.is_some() {
- &["<resume_ty>", "<yield_ty>", "<return_ty>", "<witness>", "<upvars>"][..]
- } else {
- &["<closure_kind>", "<closure_signature>", "<upvars>"][..]
- };
-
- params.extend(dummy_args.iter().enumerate().map(|(i, &arg)| ty::GenericParamDef {
- index: type_start + i as u32,
- name: Symbol::intern(arg),
- def_id,
- pure_wrt_drop: false,
- kind: ty::GenericParamDefKind::Type { has_default: false, synthetic: false },
- }));
- }
-
- // provide junk type parameter defs for const blocks.
- if let Node::AnonConst(_) = node {
- let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id));
- if let Node::Expr(&Expr { kind: ExprKind::ConstBlock(_), .. }) = parent_node {
- params.push(ty::GenericParamDef {
- index: type_start,
- name: Symbol::intern("<const_ty>"),
- def_id,
- pure_wrt_drop: false,
- kind: ty::GenericParamDefKind::Type { has_default: false, synthetic: false },
- });
- }
- }
-
- let param_def_id_to_index = params.iter().map(|param| (param.def_id, param.index)).collect();
-
- ty::Generics {
- parent: parent_def_id,
- parent_count,
- params,
- param_def_id_to_index,
- has_self: has_self || parent_has_self,
- has_late_bound_regions: has_late_bound_regions(tcx, node),
- }
-}
-
-fn are_suggestable_generic_args(generic_args: &[hir::GenericArg<'_>]) -> bool {
- generic_args.iter().any(|arg| match arg {
- hir::GenericArg::Type(ty) => is_suggestable_infer_ty(ty),
- hir::GenericArg::Infer(_) => true,
- _ => false,
- })
-}
-
-/// Whether `ty` is a type with `_` placeholders that can be inferred. Used in diagnostics only to
-/// use inference to provide suggestions for the appropriate type if possible.
-fn is_suggestable_infer_ty(ty: &hir::Ty<'_>) -> bool {
- debug!(?ty);
- use hir::TyKind::*;
- match &ty.kind {
- Infer => true,
- Slice(ty) => is_suggestable_infer_ty(ty),
- Array(ty, length) => {
- is_suggestable_infer_ty(ty) || matches!(length, hir::ArrayLen::Infer(_, _))
- }
- Tup(tys) => tys.iter().any(is_suggestable_infer_ty),
- Ptr(mut_ty) | Rptr(_, mut_ty) => is_suggestable_infer_ty(mut_ty.ty),
- OpaqueDef(_, generic_args, _) => are_suggestable_generic_args(generic_args),
- Path(hir::QPath::TypeRelative(ty, segment)) => {
- is_suggestable_infer_ty(ty) || are_suggestable_generic_args(segment.args().args)
- }
- Path(hir::QPath::Resolved(ty_opt, hir::Path { segments, .. })) => {
- ty_opt.map_or(false, is_suggestable_infer_ty)
- || segments.iter().any(|segment| are_suggestable_generic_args(segment.args().args))
- }
- _ => false,
- }
-}
-
-pub fn get_infer_ret_ty<'hir>(output: &'hir hir::FnRetTy<'hir>) -> Option<&'hir hir::Ty<'hir>> {
- if let hir::FnRetTy::Return(ty) = output {
- if is_suggestable_infer_ty(ty) {
- return Some(&*ty);
- }
- }
- None
-}
-
-#[instrument(level = "debug", skip(tcx))]
-fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
- use rustc_hir::Node::*;
- use rustc_hir::*;
-
- let def_id = def_id.expect_local();
- let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-
- let icx = ItemCtxt::new(tcx, def_id.to_def_id());
-
- match tcx.hir().get(hir_id) {
- TraitItem(hir::TraitItem {
- kind: TraitItemKind::Fn(sig, TraitFn::Provided(_)),
- generics,
- ..
- })
- | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), .. }) => {
- infer_return_ty_for_fn_sig(tcx, sig, generics, def_id, &icx)
- }
-
- ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), generics, .. }) => {
- // Do not try to inference the return type for a impl method coming from a trait
- if let Item(hir::Item { kind: ItemKind::Impl(i), .. }) =
- tcx.hir().get(tcx.hir().get_parent_node(hir_id))
- && i.of_trait.is_some()
- {
- <dyn AstConv<'_>>::ty_of_fn(
- &icx,
- hir_id,
- sig.header.unsafety,
- sig.header.abi,
- sig.decl,
- Some(generics),
- None,
- )
- } else {
- infer_return_ty_for_fn_sig(tcx, sig, generics, def_id, &icx)
- }
- }
-
- TraitItem(hir::TraitItem {
- kind: TraitItemKind::Fn(FnSig { header, decl, span: _ }, _),
- generics,
- ..
- }) => <dyn AstConv<'_>>::ty_of_fn(
- &icx,
- hir_id,
- header.unsafety,
- header.abi,
- decl,
- Some(generics),
- None,
- ),
-
- ForeignItem(&hir::ForeignItem { kind: ForeignItemKind::Fn(fn_decl, _, _), .. }) => {
- let abi = tcx.hir().get_foreign_abi(hir_id);
- compute_sig_of_foreign_fn_decl(tcx, def_id.to_def_id(), fn_decl, abi)
- }
-
- Ctor(data) | Variant(hir::Variant { data, .. }) if data.ctor_hir_id().is_some() => {
- let ty = tcx.type_of(tcx.hir().get_parent_item(hir_id));
- let inputs =
- data.fields().iter().map(|f| tcx.type_of(tcx.hir().local_def_id(f.hir_id)));
- ty::Binder::dummy(tcx.mk_fn_sig(
- inputs,
- ty,
- false,
- hir::Unsafety::Normal,
- abi::Abi::Rust,
- ))
- }
-
- Expr(&hir::Expr { kind: hir::ExprKind::Closure { .. }, .. }) => {
- // Closure signatures are not like other function
- // signatures and cannot be accessed through `fn_sig`. For
- // example, a closure signature excludes the `self`
- // argument. In any case they are embedded within the
- // closure type as part of the `ClosureSubsts`.
- //
- // To get the signature of a closure, you should use the
- // `sig` method on the `ClosureSubsts`:
- //
- // substs.as_closure().sig(def_id, tcx)
- bug!(
- "to get the signature of a closure, use `substs.as_closure().sig()` not `fn_sig()`",
- );
- }
-
- x => {
- bug!("unexpected sort of node in fn_sig(): {:?}", x);
- }
- }
-}
-
-fn infer_return_ty_for_fn_sig<'tcx>(
- tcx: TyCtxt<'tcx>,
- sig: &hir::FnSig<'_>,
- generics: &hir::Generics<'_>,
- def_id: LocalDefId,
- icx: &ItemCtxt<'tcx>,
-) -> ty::PolyFnSig<'tcx> {
- let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-
- match get_infer_ret_ty(&sig.decl.output) {
- Some(ty) => {
- let fn_sig = tcx.typeck(def_id).liberated_fn_sigs()[hir_id];
- // Typeck doesn't expect erased regions to be returned from `type_of`.
- let fn_sig = tcx.fold_regions(fn_sig, |r, _| match *r {
- ty::ReErased => tcx.lifetimes.re_static,
- _ => r,
- });
- let fn_sig = ty::Binder::dummy(fn_sig);
-
- let mut visitor = HirPlaceholderCollector::default();
- visitor.visit_ty(ty);
- let mut diag = bad_placeholder(tcx, visitor.0, "return type");
- let ret_ty = fn_sig.skip_binder().output();
- if ret_ty.is_suggestable(tcx, false) {
- diag.span_suggestion(
- ty.span,
- "replace with the correct return type",
- ret_ty,
- Applicability::MachineApplicable,
- );
- } else if matches!(ret_ty.kind(), ty::FnDef(..)) {
- let fn_sig = ret_ty.fn_sig(tcx);
- if fn_sig
- .skip_binder()
- .inputs_and_output
- .iter()
- .all(|t| t.is_suggestable(tcx, false))
- {
- diag.span_suggestion(
- ty.span,
- "replace with the correct return type",
- fn_sig,
- Applicability::MachineApplicable,
- );
- }
- } else if ret_ty.is_closure() {
- // We're dealing with a closure, so we should suggest using `impl Fn` or trait bounds
- // to prevent the user from getting a papercut while trying to use the unique closure
- // syntax (e.g. `[closure@src/lib.rs:2:5: 2:9]`).
- diag.help("consider using an `Fn`, `FnMut`, or `FnOnce` trait bound");
- diag.note("for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html");
- }
- diag.emit();
-
- fn_sig
- }
- None => <dyn AstConv<'_>>::ty_of_fn(
- icx,
- hir_id,
- sig.header.unsafety,
- sig.header.abi,
- sig.decl,
- Some(generics),
- None,
- ),
- }
-}
-
-fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::TraitRef<'_>> {
- let icx = ItemCtxt::new(tcx, def_id);
- match tcx.hir().expect_item(def_id.expect_local()).kind {
- hir::ItemKind::Impl(ref impl_) => impl_.of_trait.as_ref().map(|ast_trait_ref| {
- let selfty = tcx.type_of(def_id);
- <dyn AstConv<'_>>::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty)
- }),
- _ => bug!(),
- }
-}
-
-fn impl_polarity(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ImplPolarity {
- let is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl);
- let item = tcx.hir().expect_item(def_id.expect_local());
- match &item.kind {
- hir::ItemKind::Impl(hir::Impl {
- polarity: hir::ImplPolarity::Negative(span),
- of_trait,
- ..
- }) => {
- if is_rustc_reservation {
- let span = span.to(of_trait.as_ref().map_or(*span, |t| t.path.span));
- tcx.sess.span_err(span, "reservation impls can't be negative");
- }
- ty::ImplPolarity::Negative
- }
- hir::ItemKind::Impl(hir::Impl {
- polarity: hir::ImplPolarity::Positive,
- of_trait: None,
- ..
- }) => {
- if is_rustc_reservation {
- tcx.sess.span_err(item.span, "reservation impls can't be inherent");
- }
- ty::ImplPolarity::Positive
- }
- hir::ItemKind::Impl(hir::Impl {
- polarity: hir::ImplPolarity::Positive,
- of_trait: Some(_),
- ..
- }) => {
- if is_rustc_reservation {
- ty::ImplPolarity::Reservation
- } else {
- ty::ImplPolarity::Positive
- }
- }
- item => bug!("impl_polarity: {:?} not an impl", item),
- }
-}
-
-/// Returns the early-bound lifetimes declared in this generics
-/// listing. For anything other than fns/methods, this is just all
-/// the lifetimes that are declared. For fns or methods, we have to
-/// screen out those that do not appear in any where-clauses etc using
-/// `resolve_lifetime::early_bound_lifetimes`.
-fn early_bound_lifetimes_from_generics<'a, 'tcx: 'a>(
- tcx: TyCtxt<'tcx>,
- generics: &'a hir::Generics<'a>,
-) -> impl Iterator<Item = &'a hir::GenericParam<'a>> + Captures<'tcx> {
- generics.params.iter().filter(move |param| match param.kind {
- GenericParamKind::Lifetime { .. } => !tcx.is_late_bound(param.hir_id),
- _ => false,
- })
-}
-
-/// Returns a list of type predicates for the definition with ID `def_id`, including inferred
-/// lifetime constraints. This includes all predicates returned by `explicit_predicates_of`, plus
-/// inferred constraints concerning which regions outlive other regions.
-#[instrument(level = "debug", skip(tcx))]
-fn predicates_defined_on(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
- let mut result = tcx.explicit_predicates_of(def_id);
- debug!("predicates_defined_on: explicit_predicates_of({:?}) = {:?}", def_id, result,);
- let inferred_outlives = tcx.inferred_outlives_of(def_id);
- if !inferred_outlives.is_empty() {
- debug!(
- "predicates_defined_on: inferred_outlives_of({:?}) = {:?}",
- def_id, inferred_outlives,
- );
- if result.predicates.is_empty() {
- result.predicates = inferred_outlives;
- } else {
- result.predicates = tcx
- .arena
- .alloc_from_iter(result.predicates.iter().chain(inferred_outlives).copied());
- }
- }
-
- debug!("predicates_defined_on({:?}) = {:?}", def_id, result);
- result
-}
-
-/// Returns a list of all type predicates (explicit and implicit) for the definition with
-/// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus
-/// `Self: Trait` predicates for traits.
-fn predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
- let mut result = tcx.predicates_defined_on(def_id);
-
- if tcx.is_trait(def_id) {
- // For traits, add `Self: Trait` predicate. This is
- // not part of the predicates that a user writes, but it
- // is something that one must prove in order to invoke a
- // method or project an associated type.
- //
- // In the chalk setup, this predicate is not part of the
- // "predicates" for a trait item. But it is useful in
- // rustc because if you directly (e.g.) invoke a trait
- // method like `Trait::method(...)`, you must naturally
- // prove that the trait applies to the types that were
- // used, and adding the predicate into this list ensures
- // that this is done.
- //
- // We use a DUMMY_SP here as a way to signal trait bounds that come
- // from the trait itself that *shouldn't* be shown as the source of
- // an obligation and instead be skipped. Otherwise we'd use
- // `tcx.def_span(def_id);`
-
- let constness = if tcx.has_attr(def_id, sym::const_trait) {
- ty::BoundConstness::ConstIfConst
- } else {
- ty::BoundConstness::NotConst
- };
-
- let span = rustc_span::DUMMY_SP;
- result.predicates =
- tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(std::iter::once((
- ty::TraitRef::identity(tcx, def_id).with_constness(constness).to_predicate(tcx),
- span,
- ))));
- }
- debug!("predicates_of(def_id={:?}) = {:?}", def_id, result);
- result
-}
-
-/// Returns a list of user-specified type predicates for the definition with ID `def_id`.
-/// N.B., this does not include any implied/inferred constraints.
-#[instrument(level = "trace", skip(tcx), ret)]
-fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
- use rustc_hir::*;
-
- let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
- let node = tcx.hir().get(hir_id);
-
- let mut is_trait = None;
- let mut is_default_impl_trait = None;
-
- let icx = ItemCtxt::new(tcx, def_id);
-
- const NO_GENERICS: &hir::Generics<'_> = hir::Generics::empty();
-
- // We use an `IndexSet` to preserves order of insertion.
- // Preserving the order of insertion is important here so as not to break UI tests.
- let mut predicates: FxIndexSet<(ty::Predicate<'_>, Span)> = FxIndexSet::default();
-
- let ast_generics = match node {
- Node::TraitItem(item) => item.generics,
-
- Node::ImplItem(item) => item.generics,
-
- Node::Item(item) => {
- match item.kind {
- ItemKind::Impl(ref impl_) => {
- if impl_.defaultness.is_default() {
- is_default_impl_trait = tcx.impl_trait_ref(def_id).map(ty::Binder::dummy);
- }
- &impl_.generics
- }
- ItemKind::Fn(.., ref generics, _)
- | ItemKind::TyAlias(_, ref generics)
- | ItemKind::Enum(_, ref generics)
- | ItemKind::Struct(_, ref generics)
- | ItemKind::Union(_, ref generics) => *generics,
-
- ItemKind::Trait(_, _, ref generics, ..) => {
- is_trait = Some(ty::TraitRef::identity(tcx, def_id));
- *generics
- }
- ItemKind::TraitAlias(ref generics, _) => {
- is_trait = Some(ty::TraitRef::identity(tcx, def_id));
- *generics
- }
- ItemKind::OpaqueTy(OpaqueTy {
- origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..),
- ..
- }) => {
- // return-position impl trait
- //
- // We don't inherit predicates from the parent here:
- // If we have, say `fn f<'a, T: 'a>() -> impl Sized {}`
- // then the return type is `f::<'static, T>::{{opaque}}`.
- //
- // If we inherited the predicates of `f` then we would
- // require that `T: 'static` to show that the return
- // type is well-formed.
- //
- // The only way to have something with this opaque type
- // is from the return type of the containing function,
- // which will ensure that the function's predicates
- // hold.
- return ty::GenericPredicates { parent: None, predicates: &[] };
- }
- ItemKind::OpaqueTy(OpaqueTy {
- ref generics,
- origin: hir::OpaqueTyOrigin::TyAlias,
- ..
- }) => {
- // type-alias impl trait
- generics
- }
-
- _ => NO_GENERICS,
- }
- }
-
- Node::ForeignItem(item) => match item.kind {
- ForeignItemKind::Static(..) => NO_GENERICS,
- ForeignItemKind::Fn(_, _, ref generics) => *generics,
- ForeignItemKind::Type => NO_GENERICS,
- },
-
- _ => NO_GENERICS,
- };
-
- let generics = tcx.generics_of(def_id);
- let parent_count = generics.parent_count as u32;
- let has_own_self = generics.has_self && parent_count == 0;
-
- // Below we'll consider the bounds on the type parameters (including `Self`)
- // and the explicit where-clauses, but to get the full set of predicates
- // on a trait we need to add in the supertrait bounds and bounds found on
- // associated types.
- if let Some(_trait_ref) = is_trait {
- predicates.extend(tcx.super_predicates_of(def_id).predicates.iter().cloned());
- }
-
- // In default impls, we can assume that the self type implements
- // the trait. So in:
- //
- // default impl Foo for Bar { .. }
- //
- // we add a default where clause `Foo: Bar`. We do a similar thing for traits
- // (see below). Recall that a default impl is not itself an impl, but rather a
- // set of defaults that can be incorporated into another impl.
- if let Some(trait_ref) = is_default_impl_trait {
- predicates.insert((trait_ref.without_const().to_predicate(tcx), tcx.def_span(def_id)));
- }
-
- // Collect the region predicates that were declared inline as
- // well. In the case of parameters declared on a fn or method, we
- // have to be careful to only iterate over early-bound regions.
- let mut index = parent_count
- + has_own_self as u32
- + early_bound_lifetimes_from_generics(tcx, ast_generics).count() as u32;
-
- trace!(?predicates);
- trace!(?ast_generics);
-
- // Collect the predicates that were written inline by the user on each
- // type parameter (e.g., `<T: Foo>`).
- for param in ast_generics.params {
- match param.kind {
- // We already dealt with early bound lifetimes above.
- GenericParamKind::Lifetime { .. } => (),
- GenericParamKind::Type { .. } => {
- let name = param.name.ident().name;
- let param_ty = ty::ParamTy::new(index, name).to_ty(tcx);
- index += 1;
-
- let mut bounds = Bounds::default();
- // Params are implicitly sized unless a `?Sized` bound is found
- <dyn AstConv<'_>>::add_implicitly_sized(
- &icx,
- &mut bounds,
- &[],
- Some((param.hir_id, ast_generics.predicates)),
- param.span,
- );
- trace!(?bounds);
- predicates.extend(bounds.predicates(tcx, param_ty));
- trace!(?predicates);
- }
- GenericParamKind::Const { .. } => {
- // Bounds on const parameters are currently not possible.
- index += 1;
- }
- }
- }
-
- trace!(?predicates);
- // Add in the bounds that appear in the where-clause.
- for predicate in ast_generics.predicates {
- match predicate {
- hir::WherePredicate::BoundPredicate(bound_pred) => {
- let ty = icx.to_ty(bound_pred.bounded_ty);
- let bound_vars = icx.tcx.late_bound_vars(bound_pred.bounded_ty.hir_id);
-
- // Keep the type around in a dummy predicate, in case of no bounds.
- // That way, `where Ty:` is not a complete noop (see #53696) and `Ty`
- // is still checked for WF.
- if bound_pred.bounds.is_empty() {
- if let ty::Param(_) = ty.kind() {
- // This is a `where T:`, which can be in the HIR from the
- // transformation that moves `?Sized` to `T`'s declaration.
- // We can skip the predicate because type parameters are
- // trivially WF, but also we *should*, to avoid exposing
- // users who never wrote `where Type:,` themselves, to
- // compiler/tooling bugs from not handling WF predicates.
- } else {
- let span = bound_pred.bounded_ty.span;
- let predicate = ty::Binder::bind_with_vars(
- ty::PredicateKind::WellFormed(ty.into()),
- bound_vars,
- );
- predicates.insert((predicate.to_predicate(tcx), span));
- }
- }
-
- let mut bounds = Bounds::default();
- <dyn AstConv<'_>>::add_bounds(
- &icx,
- ty,
- bound_pred.bounds.iter(),
- &mut bounds,
- bound_vars,
- );
- predicates.extend(bounds.predicates(tcx, ty));
- }
-
- hir::WherePredicate::RegionPredicate(region_pred) => {
- let r1 = <dyn AstConv<'_>>::ast_region_to_region(&icx, ®ion_pred.lifetime, None);
- predicates.extend(region_pred.bounds.iter().map(|bound| {
- let (r2, span) = match bound {
- hir::GenericBound::Outlives(lt) => {
- (<dyn AstConv<'_>>::ast_region_to_region(&icx, lt, None), lt.span)
- }
- _ => bug!(),
- };
- let pred = ty::Binder::dummy(ty::PredicateKind::RegionOutlives(
- ty::OutlivesPredicate(r1, r2),
- ))
- .to_predicate(icx.tcx);
-
- (pred, span)
- }))
- }
-
- hir::WherePredicate::EqPredicate(..) => {
- // FIXME(#20041)
- }
- }
- }
-
- if tcx.features().generic_const_exprs {
- predicates.extend(const_evaluatable_predicates_of(tcx, def_id.expect_local()));
- }
-
- let mut predicates: Vec<_> = predicates.into_iter().collect();
-
- // Subtle: before we store the predicates into the tcx, we
- // sort them so that predicates like `T: Foo<Item=U>` come
- // before uses of `U`. This avoids false ambiguity errors
- // in trait checking. See `setup_constraining_predicates`
- // for details.
- if let Node::Item(&Item { kind: ItemKind::Impl { .. }, .. }) = node {
- let self_ty = tcx.type_of(def_id);
- let trait_ref = tcx.impl_trait_ref(def_id);
- cgp::setup_constraining_predicates(
- tcx,
- &mut predicates,
- trait_ref,
- &mut cgp::parameters_for_impl(self_ty, trait_ref),
- );
- }
-
- ty::GenericPredicates {
- parent: generics.parent,
- predicates: tcx.arena.alloc_from_iter(predicates),
- }
-}
-
-fn const_evaluatable_predicates_of<'tcx>(
- tcx: TyCtxt<'tcx>,
- def_id: LocalDefId,
-) -> FxIndexSet<(ty::Predicate<'tcx>, Span)> {
- struct ConstCollector<'tcx> {
- tcx: TyCtxt<'tcx>,
- preds: FxIndexSet<(ty::Predicate<'tcx>, Span)>,
- }
-
- impl<'tcx> intravisit::Visitor<'tcx> for ConstCollector<'tcx> {
- fn visit_anon_const(&mut self, c: &'tcx hir::AnonConst) {
- let def_id = self.tcx.hir().local_def_id(c.hir_id);
- let ct = ty::Const::from_anon_const(self.tcx, def_id);
- if let ty::ConstKind::Unevaluated(uv) = ct.kind() {
- assert_eq!(uv.promoted, ());
- let span = self.tcx.hir().span(c.hir_id);
- self.preds.insert((
- ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv))
- .to_predicate(self.tcx),
- span,
- ));
- }
- }
-
- fn visit_const_param_default(&mut self, _param: HirId, _ct: &'tcx hir::AnonConst) {
- // Do not look into const param defaults,
- // these get checked when they are actually instantiated.
- //
- // We do not want the following to error:
- //
- // struct Foo<const N: usize, const M: usize = { N + 1 }>;
- // struct Bar<const N: usize>(Foo<N, 3>);
- }
- }
-
- let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
- let node = tcx.hir().get(hir_id);
-
- let mut collector = ConstCollector { tcx, preds: FxIndexSet::default() };
- if let hir::Node::Item(item) = node && let hir::ItemKind::Impl(ref impl_) = item.kind {
- if let Some(of_trait) = &impl_.of_trait {
- debug!("const_evaluatable_predicates_of({:?}): visit impl trait_ref", def_id);
- collector.visit_trait_ref(of_trait);
- }
-
- debug!("const_evaluatable_predicates_of({:?}): visit_self_ty", def_id);
- collector.visit_ty(impl_.self_ty);
- }
-
- if let Some(generics) = node.generics() {
- debug!("const_evaluatable_predicates_of({:?}): visit_generics", def_id);
- collector.visit_generics(generics);
- }
-
- if let Some(fn_sig) = tcx.hir().fn_sig_by_hir_id(hir_id) {
- debug!("const_evaluatable_predicates_of({:?}): visit_fn_decl", def_id);
- collector.visit_fn_decl(fn_sig.decl);
- }
- debug!("const_evaluatable_predicates_of({:?}) = {:?}", def_id, collector.preds);
-
- collector.preds
-}
-
-fn trait_explicit_predicates_and_bounds(
- tcx: TyCtxt<'_>,
- def_id: LocalDefId,
-) -> ty::GenericPredicates<'_> {
- assert_eq!(tcx.def_kind(def_id), DefKind::Trait);
- gather_explicit_predicates_of(tcx, def_id.to_def_id())
-}
-
-fn explicit_predicates_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> ty::GenericPredicates<'tcx> {
- let def_kind = tcx.def_kind(def_id);
- if let DefKind::Trait = def_kind {
- // Remove bounds on associated types from the predicates, they will be
- // returned by `explicit_item_bounds`.
- let predicates_and_bounds = tcx.trait_explicit_predicates_and_bounds(def_id.expect_local());
- let trait_identity_substs = InternalSubsts::identity_for_item(tcx, def_id);
-
- let is_assoc_item_ty = |ty: Ty<'tcx>| {
- // For a predicate from a where clause to become a bound on an
- // associated type:
- // * It must use the identity substs of the item.
- // * Since any generic parameters on the item are not in scope,
- // this means that the item is not a GAT, and its identity
- // substs are the same as the trait's.
- // * It must be an associated type for this trait (*not* a
- // supertrait).
- if let ty::Projection(projection) = ty.kind() {
- projection.substs == trait_identity_substs
- && tcx.associated_item(projection.item_def_id).container_id(tcx) == def_id
- } else {
- false
- }
- };
-
- let predicates: Vec<_> = predicates_and_bounds
- .predicates
- .iter()
- .copied()
- .filter(|(pred, _)| match pred.kind().skip_binder() {
- ty::PredicateKind::Trait(tr) => !is_assoc_item_ty(tr.self_ty()),
- ty::PredicateKind::Projection(proj) => {
- !is_assoc_item_ty(proj.projection_ty.self_ty())
- }
- ty::PredicateKind::TypeOutlives(outlives) => !is_assoc_item_ty(outlives.0),
- _ => true,
- })
- .collect();
- if predicates.len() == predicates_and_bounds.predicates.len() {
- predicates_and_bounds
- } else {
- ty::GenericPredicates {
- parent: predicates_and_bounds.parent,
- predicates: tcx.arena.alloc_slice(&predicates),
- }
- }
- } else {
- if matches!(def_kind, DefKind::AnonConst) && tcx.lazy_normalization() {
- let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
- if tcx.hir().opt_const_param_default_param_hir_id(hir_id).is_some() {
- // In `generics_of` we set the generics' parent to be our parent's parent which means that
- // we lose out on the predicates of our actual parent if we dont return those predicates here.
- // (See comment in `generics_of` for more information on why the parent shenanigans is necessary)
- //
- // struct Foo<T, const N: usize = { <T as Trait>::ASSOC }>(T) where T: Trait;
- // ^^^ ^^^^^^^^^^^^^^^^^^^^^^^ the def id we are calling
- // ^^^ explicit_predicates_of on
- // parent item we dont have set as the
- // parent of generics returned by `generics_of`
- //
- // In the above code we want the anon const to have predicates in its param env for `T: Trait`
- let item_def_id = tcx.hir().get_parent_item(hir_id);
- // In the above code example we would be calling `explicit_predicates_of(Foo)` here
- return tcx.explicit_predicates_of(item_def_id);
- }
- }
- gather_explicit_predicates_of(tcx, def_id)
- }
-}
-
-/// Converts a specific `GenericBound` from the AST into a set of
-/// predicates that apply to the self type. A vector is returned
-/// because this can be anywhere from zero predicates (`T: ?Sized` adds no
-/// predicates) to one (`T: Foo`) to many (`T: Bar<X = i32>` adds `T: Bar`
-/// and `<T as Bar>::X == i32`).
-fn predicates_from_bound<'tcx>(
- astconv: &dyn AstConv<'tcx>,
- param_ty: Ty<'tcx>,
- bound: &'tcx hir::GenericBound<'tcx>,
- bound_vars: &'tcx ty::List<ty::BoundVariableKind>,
-) -> Vec<(ty::Predicate<'tcx>, Span)> {
- let mut bounds = Bounds::default();
- astconv.add_bounds(param_ty, [bound].into_iter(), &mut bounds, bound_vars);
- bounds.predicates(astconv.tcx(), param_ty).collect()
-}
-
-fn compute_sig_of_foreign_fn_decl<'tcx>(
- tcx: TyCtxt<'tcx>,
- def_id: DefId,
- decl: &'tcx hir::FnDecl<'tcx>,
- abi: abi::Abi,
-) -> ty::PolyFnSig<'tcx> {
- let unsafety = if abi == abi::Abi::RustIntrinsic {
- intrinsic_operation_unsafety(tcx.item_name(def_id))
- } else {
- hir::Unsafety::Unsafe
- };
- let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
- let fty = <dyn AstConv<'_>>::ty_of_fn(
- &ItemCtxt::new(tcx, def_id),
- hir_id,
- unsafety,
- abi,
- decl,
- None,
- None,
- );
-
- // Feature gate SIMD types in FFI, since I am not sure that the
- // ABIs are handled at all correctly. -huonw
- if abi != abi::Abi::RustIntrinsic
- && abi != abi::Abi::PlatformIntrinsic
- && !tcx.features().simd_ffi
- {
- let check = |ast_ty: &hir::Ty<'_>, ty: Ty<'_>| {
- if ty.is_simd() {
- let snip = tcx
- .sess
- .source_map()
- .span_to_snippet(ast_ty.span)
- .map_or_else(|_| String::new(), |s| format!(" `{}`", s));
- tcx.sess
- .struct_span_err(
- ast_ty.span,
- &format!(
- "use of SIMD type{} in FFI is highly experimental and \
- may result in invalid code",
- snip
- ),
- )
- .help("add `#![feature(simd_ffi)]` to the crate attributes to enable")
- .emit();
- }
- };
- for (input, ty) in iter::zip(decl.inputs, fty.inputs().skip_binder()) {
- check(input, *ty)
- }
- if let hir::FnRetTy::Return(ref ty) = decl.output {
- check(ty, fty.output().skip_binder())
- }
- }
-
- fty
-}
-
-fn is_foreign_item(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
- match tcx.hir().get_if_local(def_id) {
- Some(Node::ForeignItem(..)) => true,
- Some(_) => false,
- _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id),
- }
-}
-
-fn generator_kind(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::GeneratorKind> {
- match tcx.hir().get_if_local(def_id) {
- Some(Node::Expr(&rustc_hir::Expr {
- kind: rustc_hir::ExprKind::Closure(&rustc_hir::Closure { body, .. }),
- ..
- })) => tcx.hir().body(body).generator_kind(),
- Some(_) => None,
- _ => bug!("generator_kind applied to non-local def-id {:?}", def_id),
- }
-}
-
-fn from_target_feature(
- tcx: TyCtxt<'_>,
- attr: &ast::Attribute,
- supported_target_features: &FxHashMap<String, Option<Symbol>>,
- target_features: &mut Vec<Symbol>,
-) {
- let Some(list) = attr.meta_item_list() else { return };
- let bad_item = |span| {
- let msg = "malformed `target_feature` attribute input";
- let code = "enable = \"..\"";
- tcx.sess
- .struct_span_err(span, msg)
- .span_suggestion(span, "must be of the form", code, Applicability::HasPlaceholders)
- .emit();
- };
- let rust_features = tcx.features();
- for item in list {
- // Only `enable = ...` is accepted in the meta-item list.
- if !item.has_name(sym::enable) {
- bad_item(item.span());
- continue;
- }
-
- // Must be of the form `enable = "..."` (a string).
- let Some(value) = item.value_str() else {
- bad_item(item.span());
- continue;
- };
-
- // We allow comma separation to enable multiple features.
- target_features.extend(value.as_str().split(',').filter_map(|feature| {
- let Some(feature_gate) = supported_target_features.get(feature) else {
- let msg =
- format!("the feature named `{}` is not valid for this target", feature);
- let mut err = tcx.sess.struct_span_err(item.span(), &msg);
- err.span_label(
- item.span(),
- format!("`{}` is not valid for this target", feature),
- );
- if let Some(stripped) = feature.strip_prefix('+') {
- let valid = supported_target_features.contains_key(stripped);
- if valid {
- err.help("consider removing the leading `+` in the feature name");
- }
- }
- err.emit();
- return None;
- };
-
- // Only allow features whose feature gates have been enabled.
- let allowed = match feature_gate.as_ref().copied() {
- Some(sym::arm_target_feature) => rust_features.arm_target_feature,
- Some(sym::hexagon_target_feature) => rust_features.hexagon_target_feature,
- Some(sym::powerpc_target_feature) => rust_features.powerpc_target_feature,
- Some(sym::mips_target_feature) => rust_features.mips_target_feature,
- Some(sym::riscv_target_feature) => rust_features.riscv_target_feature,
- Some(sym::avx512_target_feature) => rust_features.avx512_target_feature,
- Some(sym::sse4a_target_feature) => rust_features.sse4a_target_feature,
- Some(sym::tbm_target_feature) => rust_features.tbm_target_feature,
- Some(sym::wasm_target_feature) => rust_features.wasm_target_feature,
- Some(sym::cmpxchg16b_target_feature) => rust_features.cmpxchg16b_target_feature,
- Some(sym::movbe_target_feature) => rust_features.movbe_target_feature,
- Some(sym::rtm_target_feature) => rust_features.rtm_target_feature,
- Some(sym::f16c_target_feature) => rust_features.f16c_target_feature,
- Some(sym::ermsb_target_feature) => rust_features.ermsb_target_feature,
- Some(sym::bpf_target_feature) => rust_features.bpf_target_feature,
- Some(sym::aarch64_ver_target_feature) => rust_features.aarch64_ver_target_feature,
- Some(name) => bug!("unknown target feature gate {}", name),
- None => true,
- };
- if !allowed {
- feature_err(
- &tcx.sess.parse_sess,
- feature_gate.unwrap(),
- item.span(),
- &format!("the target feature `{}` is currently unstable", feature),
- )
- .emit();
- }
- Some(Symbol::intern(feature))
- }));
- }
-}
-
-fn linkage_by_name(tcx: TyCtxt<'_>, def_id: LocalDefId, name: &str) -> Linkage {
- use rustc_middle::mir::mono::Linkage::*;
-
- // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
- // applicable to variable declarations and may not really make sense for
- // Rust code in the first place but allow them anyway and trust that the
- // user knows what they're doing. Who knows, unanticipated use cases may pop
- // up in the future.
- //
- // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
- // and don't have to be, LLVM treats them as no-ops.
- match name {
- "appending" => Appending,
- "available_externally" => AvailableExternally,
- "common" => Common,
- "extern_weak" => ExternalWeak,
- "external" => External,
- "internal" => Internal,
- "linkonce" => LinkOnceAny,
- "linkonce_odr" => LinkOnceODR,
- "private" => Private,
- "weak" => WeakAny,
- "weak_odr" => WeakODR,
- _ => tcx.sess.span_fatal(tcx.def_span(def_id), "invalid linkage specified"),
- }
-}
-
-fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs {
- if cfg!(debug_assertions) {
- let def_kind = tcx.def_kind(did);
- assert!(
- def_kind.has_codegen_attrs(),
- "unexpected `def_kind` in `codegen_fn_attrs`: {def_kind:?}",
- );
- }
-
- let did = did.expect_local();
- let attrs = tcx.hir().attrs(tcx.hir().local_def_id_to_hir_id(did));
- let mut codegen_fn_attrs = CodegenFnAttrs::new();
- if tcx.should_inherit_track_caller(did) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
- }
-
- // The panic_no_unwind function called by TerminatorKind::Abort will never
- // unwind. If the panic handler that it invokes unwind then it will simply
- // call the panic handler again.
- if Some(did.to_def_id()) == tcx.lang_items().panic_no_unwind() {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND;
- }
-
- let supported_target_features = tcx.supported_target_features(LOCAL_CRATE);
-
- let mut inline_span = None;
- let mut link_ordinal_span = None;
- let mut no_sanitize_span = None;
- for attr in attrs.iter() {
- if attr.has_name(sym::cold) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD;
- } else if attr.has_name(sym::rustc_allocator) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR;
- } else if attr.has_name(sym::ffi_returns_twice) {
- if tcx.is_foreign_item(did) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_RETURNS_TWICE;
- } else {
- // `#[ffi_returns_twice]` is only allowed `extern fn`s.
- struct_span_err!(
- tcx.sess,
- attr.span,
- E0724,
- "`#[ffi_returns_twice]` may only be used on foreign functions"
- )
- .emit();
- }
- } else if attr.has_name(sym::ffi_pure) {
- if tcx.is_foreign_item(did) {
- if attrs.iter().any(|a| a.has_name(sym::ffi_const)) {
- // `#[ffi_const]` functions cannot be `#[ffi_pure]`
- struct_span_err!(
- tcx.sess,
- attr.span,
- E0757,
- "`#[ffi_const]` function cannot be `#[ffi_pure]`"
- )
- .emit();
- } else {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_PURE;
- }
- } else {
- // `#[ffi_pure]` is only allowed on foreign functions
- struct_span_err!(
- tcx.sess,
- attr.span,
- E0755,
- "`#[ffi_pure]` may only be used on foreign functions"
- )
- .emit();
- }
- } else if attr.has_name(sym::ffi_const) {
- if tcx.is_foreign_item(did) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_CONST;
- } else {
- // `#[ffi_const]` is only allowed on foreign functions
- struct_span_err!(
- tcx.sess,
- attr.span,
- E0756,
- "`#[ffi_const]` may only be used on foreign functions"
- )
- .emit();
- }
- } else if attr.has_name(sym::rustc_allocator_nounwind) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND;
- } else if attr.has_name(sym::rustc_reallocator) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::REALLOCATOR;
- } else if attr.has_name(sym::rustc_deallocator) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::DEALLOCATOR;
- } else if attr.has_name(sym::rustc_allocator_zeroed) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR_ZEROED;
- } else if attr.has_name(sym::naked) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED;
- } else if attr.has_name(sym::no_mangle) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
- } else if attr.has_name(sym::no_coverage) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE;
- } else if attr.has_name(sym::rustc_std_internal_symbol) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
- } else if attr.has_name(sym::used) {
- let inner = attr.meta_item_list();
- match inner.as_deref() {
- Some([item]) if item.has_name(sym::linker) => {
- if !tcx.features().used_with_arg {
- feature_err(
- &tcx.sess.parse_sess,
- sym::used_with_arg,
- attr.span,
- "`#[used(linker)]` is currently unstable",
- )
- .emit();
- }
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED_LINKER;
- }
- Some([item]) if item.has_name(sym::compiler) => {
- if !tcx.features().used_with_arg {
- feature_err(
- &tcx.sess.parse_sess,
- sym::used_with_arg,
- attr.span,
- "`#[used(compiler)]` is currently unstable",
- )
- .emit();
- }
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED;
- }
- Some(_) => {
- tcx.sess.emit_err(errors::ExpectedUsedSymbol { span: attr.span });
- }
- None => {
- // Unfortunately, unconditionally using `llvm.used` causes
- // issues in handling `.init_array` with the gold linker,
- // but using `llvm.compiler.used` caused a nontrival amount
- // of unintentional ecosystem breakage -- particularly on
- // Mach-O targets.
- //
- // As a result, we emit `llvm.compiler.used` only on ELF
- // targets. This is somewhat ad-hoc, but actually follows
- // our pre-LLVM 13 behavior (prior to the ecosystem
- // breakage), and seems to match `clang`'s behavior as well
- // (both before and after LLVM 13), possibly because they
- // have similar compatibility concerns to us. See
- // https://github.com/rust-lang/rust/issues/47384#issuecomment-1019080146
- // and following comments for some discussion of this, as
- // well as the comments in `rustc_codegen_llvm` where these
- // flags are handled.
- //
- // Anyway, to be clear: this is still up in the air
- // somewhat, and is subject to change in the future (which
- // is a good thing, because this would ideally be a bit
- // more firmed up).
- let is_like_elf = !(tcx.sess.target.is_like_osx
- || tcx.sess.target.is_like_windows
- || tcx.sess.target.is_like_wasm);
- codegen_fn_attrs.flags |= if is_like_elf {
- CodegenFnAttrFlags::USED
- } else {
- CodegenFnAttrFlags::USED_LINKER
- };
- }
- }
- } else if attr.has_name(sym::cmse_nonsecure_entry) {
- if !matches!(tcx.fn_sig(did).abi(), abi::Abi::C { .. }) {
- struct_span_err!(
- tcx.sess,
- attr.span,
- E0776,
- "`#[cmse_nonsecure_entry]` requires C ABI"
- )
- .emit();
- }
- if !tcx.sess.target.llvm_target.contains("thumbv8m") {
- struct_span_err!(tcx.sess, attr.span, E0775, "`#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension")
- .emit();
- }
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY;
- } else if attr.has_name(sym::thread_local) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL;
- } else if attr.has_name(sym::track_caller) {
- if !tcx.is_closure(did.to_def_id()) && tcx.fn_sig(did).abi() != abi::Abi::Rust {
- struct_span_err!(tcx.sess, attr.span, E0737, "`#[track_caller]` requires Rust ABI")
- .emit();
- }
- if tcx.is_closure(did.to_def_id()) && !tcx.features().closure_track_caller {
- feature_err(
- &tcx.sess.parse_sess,
- sym::closure_track_caller,
- attr.span,
- "`#[track_caller]` on closures is currently unstable",
- )
- .emit();
- }
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
- } else if attr.has_name(sym::export_name) {
- if let Some(s) = attr.value_str() {
- if s.as_str().contains('\0') {
- // `#[export_name = ...]` will be converted to a null-terminated string,
- // so it may not contain any null characters.
- struct_span_err!(
- tcx.sess,
- attr.span,
- E0648,
- "`export_name` may not contain null characters"
- )
- .emit();
- }
- codegen_fn_attrs.export_name = Some(s);
- }
- } else if attr.has_name(sym::target_feature) {
- if !tcx.is_closure(did.to_def_id())
- && tcx.fn_sig(did).unsafety() == hir::Unsafety::Normal
- {
- if tcx.sess.target.is_like_wasm || tcx.sess.opts.actually_rustdoc {
- // The `#[target_feature]` attribute is allowed on
- // WebAssembly targets on all functions, including safe
- // ones. Other targets require that `#[target_feature]` is
- // only applied to unsafe functions (pending the
- // `target_feature_11` feature) because on most targets
- // execution of instructions that are not supported is
- // considered undefined behavior. For WebAssembly which is a
- // 100% safe target at execution time it's not possible to
- // execute undefined instructions, and even if a future
- // feature was added in some form for this it would be a
- // deterministic trap. There is no undefined behavior when
- // executing WebAssembly so `#[target_feature]` is allowed
- // on safe functions (but again, only for WebAssembly)
- //
- // Note that this is also allowed if `actually_rustdoc` so
- // if a target is documenting some wasm-specific code then
- // it's not spuriously denied.
- } else if !tcx.features().target_feature_11 {
- let mut err = feature_err(
- &tcx.sess.parse_sess,
- sym::target_feature_11,
- attr.span,
- "`#[target_feature(..)]` can only be applied to `unsafe` functions",
- );
- err.span_label(tcx.def_span(did), "not an `unsafe` function");
- err.emit();
- } else {
- check_target_feature_trait_unsafe(tcx, did, attr.span);
- }
- }
- from_target_feature(
- tcx,
- attr,
- supported_target_features,
- &mut codegen_fn_attrs.target_features,
- );
- } else if attr.has_name(sym::linkage) {
- if let Some(val) = attr.value_str() {
- codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, did, val.as_str()));
- }
- } else if attr.has_name(sym::link_section) {
- if let Some(val) = attr.value_str() {
- if val.as_str().bytes().any(|b| b == 0) {
- let msg = format!(
- "illegal null byte in link_section \
- value: `{}`",
- &val
- );
- tcx.sess.span_err(attr.span, &msg);
- } else {
- codegen_fn_attrs.link_section = Some(val);
- }
- }
- } else if attr.has_name(sym::link_name) {
- codegen_fn_attrs.link_name = attr.value_str();
- } else if attr.has_name(sym::link_ordinal) {
- link_ordinal_span = Some(attr.span);
- if let ordinal @ Some(_) = check_link_ordinal(tcx, attr) {
- codegen_fn_attrs.link_ordinal = ordinal;
- }
- } else if attr.has_name(sym::no_sanitize) {
- no_sanitize_span = Some(attr.span);
- if let Some(list) = attr.meta_item_list() {
- for item in list.iter() {
- if item.has_name(sym::address) {
- codegen_fn_attrs.no_sanitize |= SanitizerSet::ADDRESS;
- } else if item.has_name(sym::cfi) {
- codegen_fn_attrs.no_sanitize |= SanitizerSet::CFI;
- } else if item.has_name(sym::memory) {
- codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMORY;
- } else if item.has_name(sym::memtag) {
- codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMTAG;
- } else if item.has_name(sym::shadow_call_stack) {
- codegen_fn_attrs.no_sanitize |= SanitizerSet::SHADOWCALLSTACK;
- } else if item.has_name(sym::thread) {
- codegen_fn_attrs.no_sanitize |= SanitizerSet::THREAD;
- } else if item.has_name(sym::hwaddress) {
- codegen_fn_attrs.no_sanitize |= SanitizerSet::HWADDRESS;
- } else {
- tcx.sess
- .struct_span_err(item.span(), "invalid argument for `no_sanitize`")
- .note("expected one of: `address`, `cfi`, `hwaddress`, `memory`, `memtag`, `shadow-call-stack`, or `thread`")
- .emit();
- }
- }
- }
- } else if attr.has_name(sym::instruction_set) {
- codegen_fn_attrs.instruction_set = match attr.meta_kind() {
- Some(MetaItemKind::List(ref items)) => match items.as_slice() {
- [NestedMetaItem::MetaItem(set)] => {
- let segments =
- set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>();
- match segments.as_slice() {
- [sym::arm, sym::a32] | [sym::arm, sym::t32] => {
- if !tcx.sess.target.has_thumb_interworking {
- struct_span_err!(
- tcx.sess.diagnostic(),
- attr.span,
- E0779,
- "target does not support `#[instruction_set]`"
- )
- .emit();
- None
- } else if segments[1] == sym::a32 {
- Some(InstructionSetAttr::ArmA32)
- } else if segments[1] == sym::t32 {
- Some(InstructionSetAttr::ArmT32)
- } else {
- unreachable!()
- }
- }
- _ => {
- struct_span_err!(
- tcx.sess.diagnostic(),
- attr.span,
- E0779,
- "invalid instruction set specified",
- )
- .emit();
- None
- }
- }
- }
- [] => {
- struct_span_err!(
- tcx.sess.diagnostic(),
- attr.span,
- E0778,
- "`#[instruction_set]` requires an argument"
- )
- .emit();
- None
- }
- _ => {
- struct_span_err!(
- tcx.sess.diagnostic(),
- attr.span,
- E0779,
- "cannot specify more than one instruction set"
- )
- .emit();
- None
- }
- },
- _ => {
- struct_span_err!(
- tcx.sess.diagnostic(),
- attr.span,
- E0778,
- "must specify an instruction set"
- )
- .emit();
- None
- }
- };
- } else if attr.has_name(sym::repr) {
- codegen_fn_attrs.alignment = match attr.meta_item_list() {
- Some(items) => match items.as_slice() {
- [item] => match item.name_value_literal() {
- Some((sym::align, literal)) => {
- let alignment = rustc_attr::parse_alignment(&literal.kind);
-
- match alignment {
- Ok(align) => Some(align),
- Err(msg) => {
- struct_span_err!(
- tcx.sess.diagnostic(),
- attr.span,
- E0589,
- "invalid `repr(align)` attribute: {}",
- msg
- )
- .emit();
-
- None
- }
- }
- }
- _ => None,
- },
- [] => None,
- _ => None,
- },
- None => None,
- };
- }
- }
-
- codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
- if !attr.has_name(sym::inline) {
- return ia;
- }
- match attr.meta_kind() {
- Some(MetaItemKind::Word) => InlineAttr::Hint,
- Some(MetaItemKind::List(ref items)) => {
- inline_span = Some(attr.span);
- if items.len() != 1 {
- struct_span_err!(
- tcx.sess.diagnostic(),
- attr.span,
- E0534,
- "expected one argument"
- )
- .emit();
- InlineAttr::None
- } else if list_contains_name(&items, sym::always) {
- InlineAttr::Always
- } else if list_contains_name(&items, sym::never) {
- InlineAttr::Never
- } else {
- struct_span_err!(
- tcx.sess.diagnostic(),
- items[0].span(),
- E0535,
- "invalid argument"
- )
- .emit();
-
- InlineAttr::None
- }
- }
- Some(MetaItemKind::NameValue(_)) => ia,
- None => ia,
- }
- });
-
- codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| {
- if !attr.has_name(sym::optimize) {
- return ia;
- }
- let err = |sp, s| struct_span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s).emit();
- match attr.meta_kind() {
- Some(MetaItemKind::Word) => {
- err(attr.span, "expected one argument");
- ia
- }
- Some(MetaItemKind::List(ref items)) => {
- inline_span = Some(attr.span);
- if items.len() != 1 {
- err(attr.span, "expected one argument");
- OptimizeAttr::None
- } else if list_contains_name(&items, sym::size) {
- OptimizeAttr::Size
- } else if list_contains_name(&items, sym::speed) {
- OptimizeAttr::Speed
- } else {
- err(items[0].span(), "invalid argument");
- OptimizeAttr::None
- }
- }
- Some(MetaItemKind::NameValue(_)) => ia,
- None => ia,
- }
- });
-
- // #73631: closures inherit `#[target_feature]` annotations
- if tcx.features().target_feature_11 && tcx.is_closure(did.to_def_id()) {
- let owner_id = tcx.parent(did.to_def_id());
- if tcx.def_kind(owner_id).has_codegen_attrs() {
- codegen_fn_attrs
- .target_features
- .extend(tcx.codegen_fn_attrs(owner_id).target_features.iter().copied());
- }
- }
-
- // If a function uses #[target_feature] it can't be inlined into general
- // purpose functions as they wouldn't have the right target features
- // enabled. For that reason we also forbid #[inline(always)] as it can't be
- // respected.
- if !codegen_fn_attrs.target_features.is_empty() {
- if codegen_fn_attrs.inline == InlineAttr::Always {
- if let Some(span) = inline_span {
- tcx.sess.span_err(
- span,
- "cannot use `#[inline(always)]` with \
- `#[target_feature]`",
- );
- }
- }
- }
-
- if !codegen_fn_attrs.no_sanitize.is_empty() {
- if codegen_fn_attrs.inline == InlineAttr::Always {
- if let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span) {
- let hir_id = tcx.hir().local_def_id_to_hir_id(did);
- tcx.struct_span_lint_hir(
- lint::builtin::INLINE_NO_SANITIZE,
- hir_id,
- no_sanitize_span,
- |lint| {
- lint.build("`no_sanitize` will have no effect after inlining")
- .span_note(inline_span, "inlining requested here")
- .emit();
- },
- )
- }
- }
- }
-
- // Weak lang items have the same semantics as "std internal" symbols in the
- // sense that they're preserved through all our LTO passes and only
- // strippable by the linker.
- //
- // Additionally weak lang items have predetermined symbol names.
- if tcx.is_weak_lang_item(did.to_def_id()) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
- }
- if let Some(name) = weak_lang_items::link_name(attrs) {
- codegen_fn_attrs.export_name = Some(name);
- codegen_fn_attrs.link_name = Some(name);
- }
- check_link_name_xor_ordinal(tcx, &codegen_fn_attrs, link_ordinal_span);
-
- // Internal symbols to the standard library all have no_mangle semantics in
- // that they have defined symbol names present in the function name. This
- // also applies to weak symbols where they all have known symbol names.
- if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
- }
-
- // Any linkage to LLVM intrinsics for now forcibly marks them all as never
- // unwinds since LLVM sometimes can't handle codegen which `invoke`s
- // intrinsic functions.
- if let Some(name) = &codegen_fn_attrs.link_name {
- if name.as_str().starts_with("llvm.") {
- codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND;
- }
- }
-
- codegen_fn_attrs
-}
-
-/// Computes the set of target features used in a function for the purposes of
-/// inline assembly.
-fn asm_target_features<'tcx>(tcx: TyCtxt<'tcx>, did: DefId) -> &'tcx FxHashSet<Symbol> {
- let mut target_features = tcx.sess.unstable_target_features.clone();
- if tcx.def_kind(did).has_codegen_attrs() {
- let attrs = tcx.codegen_fn_attrs(did);
- target_features.extend(&attrs.target_features);
- match attrs.instruction_set {
- None => {}
- Some(InstructionSetAttr::ArmA32) => {
- target_features.remove(&sym::thumb_mode);
- }
- Some(InstructionSetAttr::ArmT32) => {
- target_features.insert(sym::thumb_mode);
- }
- }
- }
-
- tcx.arena.alloc(target_features)
-}
-
-/// Checks if the provided DefId is a method in a trait impl for a trait which has track_caller
-/// applied to the method prototype.
-fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
- if let Some(impl_item) = tcx.opt_associated_item(def_id)
- && let ty::AssocItemContainer::ImplContainer = impl_item.container
- && let Some(trait_item) = impl_item.trait_item_def_id
- {
- return tcx
- .codegen_fn_attrs(trait_item)
- .flags
- .intersects(CodegenFnAttrFlags::TRACK_CALLER);
- }
-
- false
-}
-
-fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &ast::Attribute) -> Option<u16> {
- use rustc_ast::{Lit, LitIntType, LitKind};
- if !tcx.features().raw_dylib && tcx.sess.target.arch == "x86" {
- feature_err(
- &tcx.sess.parse_sess,
- sym::raw_dylib,
- attr.span,
- "`#[link_ordinal]` is unstable on x86",
- )
- .emit();
- }
- let meta_item_list = attr.meta_item_list();
- let meta_item_list: Option<&[ast::NestedMetaItem]> = meta_item_list.as_ref().map(Vec::as_ref);
- let sole_meta_list = match meta_item_list {
- Some([item]) => item.literal(),
- Some(_) => {
- tcx.sess
- .struct_span_err(attr.span, "incorrect number of arguments to `#[link_ordinal]`")
- .note("the attribute requires exactly one argument")
- .emit();
- return None;
- }
- _ => None,
- };
- if let Some(Lit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) = sole_meta_list {
- // According to the table at https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#import-header,
- // the ordinal must fit into 16 bits. Similarly, the Ordinal field in COFFShortExport (defined
- // in llvm/include/llvm/Object/COFFImportFile.h), which we use to communicate import information
- // to LLVM for `#[link(kind = "raw-dylib"_])`, is also defined to be uint16_t.
- //
- // FIXME: should we allow an ordinal of 0? The MSVC toolchain has inconsistent support for this:
- // both LINK.EXE and LIB.EXE signal errors and abort when given a .DEF file that specifies
- // a zero ordinal. However, llvm-dlltool is perfectly happy to generate an import library
- // for such a .DEF file, and MSVC's LINK.EXE is also perfectly happy to consume an import
- // library produced by LLVM with an ordinal of 0, and it generates an .EXE. (I don't know yet
- // if the resulting EXE runs, as I haven't yet built the necessary DLL -- see earlier comment
- // about LINK.EXE failing.)
- if *ordinal <= u16::MAX as u128 {
- Some(*ordinal as u16)
- } else {
- let msg = format!("ordinal value in `link_ordinal` is too large: `{}`", &ordinal);
- tcx.sess
- .struct_span_err(attr.span, &msg)
- .note("the value may not exceed `u16::MAX`")
- .emit();
- None
- }
- } else {
- tcx.sess
- .struct_span_err(attr.span, "illegal ordinal format in `link_ordinal`")
- .note("an unsuffixed integer value, e.g., `1`, is expected")
- .emit();
- None
- }
-}
-
-fn check_link_name_xor_ordinal(
- tcx: TyCtxt<'_>,
- codegen_fn_attrs: &CodegenFnAttrs,
- inline_span: Option<Span>,
-) {
- if codegen_fn_attrs.link_name.is_none() || codegen_fn_attrs.link_ordinal.is_none() {
- return;
- }
- let msg = "cannot use `#[link_name]` with `#[link_ordinal]`";
- if let Some(span) = inline_span {
- tcx.sess.span_err(span, msg);
- } else {
- tcx.sess.err(msg);
- }
-}
-
-/// Checks the function annotated with `#[target_feature]` is not a safe
-/// trait method implementation, reporting an error if it is.
-fn check_target_feature_trait_unsafe(tcx: TyCtxt<'_>, id: LocalDefId, attr_span: Span) {
- let hir_id = tcx.hir().local_def_id_to_hir_id(id);
- let node = tcx.hir().get(hir_id);
- if let Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), .. }) = node {
- let parent_id = tcx.hir().get_parent_item(hir_id);
- let parent_item = tcx.hir().expect_item(parent_id);
- if let hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) = parent_item.kind {
- tcx.sess
- .struct_span_err(
- attr_span,
- "`#[target_feature(..)]` cannot be applied to safe trait method",
- )
- .span_label(attr_span, "cannot be applied to safe trait method")
- .span_label(tcx.def_span(id), "not an `unsafe` function")
- .emit();
- }
- }
-}
projects / rustc.git / blobdiff