//! Collects lang items: items marked with `#[lang = "..."]` attribute. //! //! This attribute to tell the compiler about semi built-in std library //! features, such as Fn family of traits. use hir_expand::name::Name; use rustc_hash::FxHashMap; use syntax::SmolStr; use triomphe::Arc; use crate::{ db::DefDatabase, path::Path, AdtId, AssocItemId, AttrDefId, CrateId, EnumId, EnumVariantId, FunctionId, ImplId, ModuleDefId, StaticId, StructId, TraitId, TypeAliasId, UnionId, }; #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)] pub enum LangItemTarget { EnumId(EnumId), Function(FunctionId), ImplDef(ImplId), Static(StaticId), Struct(StructId), Union(UnionId), TypeAlias(TypeAliasId), Trait(TraitId), EnumVariant(EnumVariantId), } impl LangItemTarget { pub fn as_enum(self) -> Option { match self { LangItemTarget::EnumId(id) => Some(id), _ => None, } } pub fn as_function(self) -> Option { match self { LangItemTarget::Function(id) => Some(id), _ => None, } } pub fn as_impl_def(self) -> Option { match self { LangItemTarget::ImplDef(id) => Some(id), _ => None, } } pub fn as_static(self) -> Option { match self { LangItemTarget::Static(id) => Some(id), _ => None, } } pub fn as_struct(self) -> Option { match self { LangItemTarget::Struct(id) => Some(id), _ => None, } } pub fn as_trait(self) -> Option { match self { LangItemTarget::Trait(id) => Some(id), _ => None, } } pub fn as_enum_variant(self) -> Option { match self { LangItemTarget::EnumVariant(id) => Some(id), _ => None, } } } #[derive(Default, Debug, Clone, PartialEq, Eq)] pub struct LangItems { items: FxHashMap, } impl LangItems { pub fn target(&self, item: LangItem) -> Option { self.items.get(&item).copied() } /// Salsa query. This will look for lang items in a specific crate. pub(crate) fn crate_lang_items_query( db: &dyn DefDatabase, krate: CrateId, ) -> Option> { let _p = tracing::info_span!("crate_lang_items_query").entered(); let mut lang_items = LangItems::default(); let crate_def_map = db.crate_def_map(krate); for (_, module_data) in crate_def_map.modules() { for impl_def in module_data.scope.impls() { lang_items.collect_lang_item(db, impl_def, LangItemTarget::ImplDef); for assoc in db.impl_data(impl_def).items.iter().copied() { match assoc { AssocItemId::FunctionId(f) => { lang_items.collect_lang_item(db, f, LangItemTarget::Function) } AssocItemId::TypeAliasId(t) => { lang_items.collect_lang_item(db, t, LangItemTarget::TypeAlias) } AssocItemId::ConstId(_) => (), } } } for def in module_data.scope.declarations() { match def { ModuleDefId::TraitId(trait_) => { lang_items.collect_lang_item(db, trait_, LangItemTarget::Trait); db.trait_data(trait_).items.iter().for_each(|&(_, assoc_id)| { if let AssocItemId::FunctionId(f) = assoc_id { lang_items.collect_lang_item(db, f, LangItemTarget::Function); } }); } ModuleDefId::AdtId(AdtId::EnumId(e)) => { lang_items.collect_lang_item(db, e, LangItemTarget::EnumId); crate_def_map.enum_definitions[&e].iter().for_each(|&id| { lang_items.collect_lang_item(db, id, LangItemTarget::EnumVariant); }); } ModuleDefId::AdtId(AdtId::StructId(s)) => { lang_items.collect_lang_item(db, s, LangItemTarget::Struct); } ModuleDefId::AdtId(AdtId::UnionId(u)) => { lang_items.collect_lang_item(db, u, LangItemTarget::Union); } ModuleDefId::FunctionId(f) => { lang_items.collect_lang_item(db, f, LangItemTarget::Function); } ModuleDefId::StaticId(s) => { lang_items.collect_lang_item(db, s, LangItemTarget::Static); } ModuleDefId::TypeAliasId(t) => { lang_items.collect_lang_item(db, t, LangItemTarget::TypeAlias); } _ => {} } } } if lang_items.items.is_empty() { None } else { Some(Arc::new(lang_items)) } } /// Salsa query. Look for a lang item, starting from the specified crate and recursively /// traversing its dependencies. pub(crate) fn lang_item_query( db: &dyn DefDatabase, start_crate: CrateId, item: LangItem, ) -> Option { let _p = tracing::info_span!("lang_item_query").entered(); if let Some(target) = db.crate_lang_items(start_crate).and_then(|it| it.items.get(&item).copied()) { return Some(target); } db.crate_graph()[start_crate] .dependencies .iter() .find_map(|dep| db.lang_item(dep.crate_id, item)) } fn collect_lang_item( &mut self, db: &dyn DefDatabase, item: T, constructor: fn(T) -> LangItemTarget, ) where T: Into + Copy, { let _p = tracing::info_span!("collect_lang_item").entered(); if let Some(lang_item) = lang_attr(db, item.into()) { self.items.entry(lang_item).or_insert_with(|| constructor(item)); } } } pub(crate) fn lang_attr(db: &dyn DefDatabase, item: AttrDefId) -> Option { let attrs = db.attrs(item); attrs.by_key("lang").string_value().and_then(LangItem::from_str) } pub(crate) fn notable_traits_in_deps( db: &dyn DefDatabase, krate: CrateId, ) -> Arc<[Arc<[TraitId]>]> { let _p = tracing::info_span!("notable_traits_in_deps", ?krate).entered(); let crate_graph = db.crate_graph(); Arc::from_iter( crate_graph.transitive_deps(krate).filter_map(|krate| db.crate_notable_traits(krate)), ) } pub(crate) fn crate_notable_traits(db: &dyn DefDatabase, krate: CrateId) -> Option> { let _p = tracing::info_span!("crate_notable_traits", ?krate).entered(); let mut traits = Vec::new(); let crate_def_map = db.crate_def_map(krate); for (_, module_data) in crate_def_map.modules() { for def in module_data.scope.declarations() { if let ModuleDefId::TraitId(trait_) = def { if db.attrs(trait_.into()).has_doc_notable_trait() { traits.push(trait_); } } } } if traits.is_empty() { None } else { Some(traits.into_iter().collect()) } } pub enum GenericRequirement { None, Minimum(usize), Exact(usize), } macro_rules! language_item_table { ( $( $(#[$attr:meta])* $variant:ident, $module:ident :: $name:ident, $method:ident, $target:expr, $generics:expr; )* ) => { /// A representation of all the valid language items in Rust. #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)] pub enum LangItem { $( #[doc = concat!("The `", stringify!($name), "` lang item.")] $(#[$attr])* $variant, )* } impl LangItem { pub fn name(self) -> SmolStr { match self { $( LangItem::$variant => SmolStr::new(stringify!($name)), )* } } /// Opposite of [`LangItem::name`] #[allow(clippy::should_implement_trait)] pub fn from_str(name: &str) -> Option { match name { $( stringify!($name) => Some(LangItem::$variant), )* _ => None, } } } } } impl LangItem { /// Opposite of [`LangItem::name`] pub fn from_name(name: &hir_expand::name::Name) -> Option { Self::from_str(name.as_str()?) } pub fn path(&self, db: &dyn DefDatabase, start_crate: CrateId) -> Option { let t = db.lang_item(start_crate, *self)?; Some(Path::LangItem(t, None)) } pub fn ty_rel_path( &self, db: &dyn DefDatabase, start_crate: CrateId, seg: Name, ) -> Option { let t = db.lang_item(start_crate, *self)?; Some(Path::LangItem(t, Some(seg))) } } language_item_table! { // Variant name, Name, Getter method name, Target Generic requirements; Sized, sym::sized, sized_trait, Target::Trait, GenericRequirement::Exact(0); Unsize, sym::unsize, unsize_trait, Target::Trait, GenericRequirement::Minimum(1); /// Trait injected by `#[derive(PartialEq)]`, (i.e. "Partial EQ"). StructuralPeq, sym::structural_peq, structural_peq_trait, Target::Trait, GenericRequirement::None; /// Trait injected by `#[derive(Eq)]`, (i.e. "Total EQ"; no, I will not apologize). StructuralTeq, sym::structural_teq, structural_teq_trait, Target::Trait, GenericRequirement::None; Copy, sym::copy, copy_trait, Target::Trait, GenericRequirement::Exact(0); Clone, sym::clone, clone_trait, Target::Trait, GenericRequirement::None; Sync, sym::sync, sync_trait, Target::Trait, GenericRequirement::Exact(0); DiscriminantKind, sym::discriminant_kind, discriminant_kind_trait, Target::Trait, GenericRequirement::None; /// The associated item of the [`DiscriminantKind`] trait. Discriminant, sym::discriminant_type, discriminant_type, Target::AssocTy, GenericRequirement::None; PointeeTrait, sym::pointee_trait, pointee_trait, Target::Trait, GenericRequirement::None; Metadata, sym::metadata_type, metadata_type, Target::AssocTy, GenericRequirement::None; DynMetadata, sym::dyn_metadata, dyn_metadata, Target::Struct, GenericRequirement::None; Freeze, sym::freeze, freeze_trait, Target::Trait, GenericRequirement::Exact(0); FnPtrTrait, sym::fn_ptr_trait, fn_ptr_trait, Target::Trait, GenericRequirement::Exact(0); FnPtrAddr, sym::fn_ptr_addr, fn_ptr_addr, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; Drop, sym::drop, drop_trait, Target::Trait, GenericRequirement::None; Destruct, sym::destruct, destruct_trait, Target::Trait, GenericRequirement::None; CoerceUnsized, sym::coerce_unsized, coerce_unsized_trait, Target::Trait, GenericRequirement::Minimum(1); DispatchFromDyn, sym::dispatch_from_dyn, dispatch_from_dyn_trait, Target::Trait, GenericRequirement::Minimum(1); // language items relating to transmutability TransmuteOpts, sym::transmute_opts, transmute_opts, Target::Struct, GenericRequirement::Exact(0); TransmuteTrait, sym::transmute_trait, transmute_trait, Target::Trait, GenericRequirement::Exact(3); Add, sym::add, add_trait, Target::Trait, GenericRequirement::Exact(1); Sub, sym::sub, sub_trait, Target::Trait, GenericRequirement::Exact(1); Mul, sym::mul, mul_trait, Target::Trait, GenericRequirement::Exact(1); Div, sym::div, div_trait, Target::Trait, GenericRequirement::Exact(1); Rem, sym::rem, rem_trait, Target::Trait, GenericRequirement::Exact(1); Neg, sym::neg, neg_trait, Target::Trait, GenericRequirement::Exact(0); Not, sym::not, not_trait, Target::Trait, GenericRequirement::Exact(0); BitXor, sym::bitxor, bitxor_trait, Target::Trait, GenericRequirement::Exact(1); BitAnd, sym::bitand, bitand_trait, Target::Trait, GenericRequirement::Exact(1); BitOr, sym::bitor, bitor_trait, Target::Trait, GenericRequirement::Exact(1); Shl, sym::shl, shl_trait, Target::Trait, GenericRequirement::Exact(1); Shr, sym::shr, shr_trait, Target::Trait, GenericRequirement::Exact(1); AddAssign, sym::add_assign, add_assign_trait, Target::Trait, GenericRequirement::Exact(1); SubAssign, sym::sub_assign, sub_assign_trait, Target::Trait, GenericRequirement::Exact(1); MulAssign, sym::mul_assign, mul_assign_trait, Target::Trait, GenericRequirement::Exact(1); DivAssign, sym::div_assign, div_assign_trait, Target::Trait, GenericRequirement::Exact(1); RemAssign, sym::rem_assign, rem_assign_trait, Target::Trait, GenericRequirement::Exact(1); BitXorAssign, sym::bitxor_assign, bitxor_assign_trait, Target::Trait, GenericRequirement::Exact(1); BitAndAssign, sym::bitand_assign, bitand_assign_trait, Target::Trait, GenericRequirement::Exact(1); BitOrAssign, sym::bitor_assign, bitor_assign_trait, Target::Trait, GenericRequirement::Exact(1); ShlAssign, sym::shl_assign, shl_assign_trait, Target::Trait, GenericRequirement::Exact(1); ShrAssign, sym::shr_assign, shr_assign_trait, Target::Trait, GenericRequirement::Exact(1); Index, sym::index, index_trait, Target::Trait, GenericRequirement::Exact(1); IndexMut, sym::index_mut, index_mut_trait, Target::Trait, GenericRequirement::Exact(1); UnsafeCell, sym::unsafe_cell, unsafe_cell_type, Target::Struct, GenericRequirement::None; VaList, sym::va_list, va_list, Target::Struct, GenericRequirement::None; Deref, sym::deref, deref_trait, Target::Trait, GenericRequirement::Exact(0); DerefMut, sym::deref_mut, deref_mut_trait, Target::Trait, GenericRequirement::Exact(0); DerefTarget, sym::deref_target, deref_target, Target::AssocTy, GenericRequirement::None; Receiver, sym::receiver, receiver_trait, Target::Trait, GenericRequirement::None; Fn, kw::fn, fn_trait, Target::Trait, GenericRequirement::Exact(1); FnMut, sym::fn_mut, fn_mut_trait, Target::Trait, GenericRequirement::Exact(1); FnOnce, sym::fn_once, fn_once_trait, Target::Trait, GenericRequirement::Exact(1); FnOnceOutput, sym::fn_once_output, fn_once_output, Target::AssocTy, GenericRequirement::None; Future, sym::future_trait, future_trait, Target::Trait, GenericRequirement::Exact(0); CoroutineState, sym::coroutine_state, coroutine_state, Target::Enum, GenericRequirement::None; Coroutine, sym::coroutine, coroutine_trait, Target::Trait, GenericRequirement::Minimum(1); Unpin, sym::unpin, unpin_trait, Target::Trait, GenericRequirement::None; Pin, sym::pin, pin_type, Target::Struct, GenericRequirement::None; PartialEq, sym::eq, eq_trait, Target::Trait, GenericRequirement::Exact(1); PartialOrd, sym::partial_ord, partial_ord_trait, Target::Trait, GenericRequirement::Exact(1); CVoid, sym::c_void, c_void, Target::Enum, GenericRequirement::None; // A number of panic-related lang items. The `panic` item corresponds to divide-by-zero and // various panic cases with `match`. The `panic_bounds_check` item is for indexing arrays. // // The `begin_unwind` lang item has a predefined symbol name and is sort of a "weak lang item" // in the sense that a crate is not required to have it defined to use it, but a final product // is required to define it somewhere. Additionally, there are restrictions on crates that use // a weak lang item, but do not have it defined. Panic, sym::panic, panic_fn, Target::Fn, GenericRequirement::Exact(0); PanicNounwind, sym::panic_nounwind, panic_nounwind, Target::Fn, GenericRequirement::Exact(0); PanicFmt, sym::panic_fmt, panic_fmt, Target::Fn, GenericRequirement::None; PanicDisplay, sym::panic_display, panic_display, Target::Fn, GenericRequirement::None; ConstPanicFmt, sym::const_panic_fmt, const_panic_fmt, Target::Fn, GenericRequirement::None; PanicBoundsCheck, sym::panic_bounds_check, panic_bounds_check_fn, Target::Fn, GenericRequirement::Exact(0); PanicMisalignedPointerDereference, sym::panic_misaligned_pointer_dereference, panic_misaligned_pointer_dereference_fn, Target::Fn, GenericRequirement::Exact(0); PanicInfo, sym::panic_info, panic_info, Target::Struct, GenericRequirement::None; PanicLocation, sym::panic_location, panic_location, Target::Struct, GenericRequirement::None; PanicImpl, sym::panic_impl, panic_impl, Target::Fn, GenericRequirement::None; PanicCannotUnwind, sym::panic_cannot_unwind, panic_cannot_unwind, Target::Fn, GenericRequirement::Exact(0); /// libstd panic entry point. Necessary for const eval to be able to catch it BeginPanic, sym::begin_panic, begin_panic_fn, Target::Fn, GenericRequirement::None; // Lang items needed for `format_args!()`. FormatAlignment, sym::format_alignment, format_alignment, Target::Enum, GenericRequirement::None; FormatArgument, sym::format_argument, format_argument, Target::Struct, GenericRequirement::None; FormatArguments, sym::format_arguments, format_arguments, Target::Struct, GenericRequirement::None; FormatCount, sym::format_count, format_count, Target::Enum, GenericRequirement::None; FormatPlaceholder, sym::format_placeholder, format_placeholder, Target::Struct, GenericRequirement::None; FormatUnsafeArg, sym::format_unsafe_arg, format_unsafe_arg, Target::Struct, GenericRequirement::None; ExchangeMalloc, sym::exchange_malloc, exchange_malloc_fn, Target::Fn, GenericRequirement::None; BoxFree, sym::box_free, box_free_fn, Target::Fn, GenericRequirement::Minimum(1); DropInPlace, sym::drop_in_place, drop_in_place_fn, Target::Fn, GenericRequirement::Minimum(1); AllocLayout, sym::alloc_layout, alloc_layout, Target::Struct, GenericRequirement::None; Start, sym::start, start_fn, Target::Fn, GenericRequirement::Exact(1); EhPersonality, sym::eh_personality, eh_personality, Target::Fn, GenericRequirement::None; EhCatchTypeinfo, sym::eh_catch_typeinfo, eh_catch_typeinfo, Target::Static, GenericRequirement::None; OwnedBox, sym::owned_box, owned_box, Target::Struct, GenericRequirement::Minimum(1); PhantomData, sym::phantom_data, phantom_data, Target::Struct, GenericRequirement::Exact(1); ManuallyDrop, sym::manually_drop, manually_drop, Target::Struct, GenericRequirement::None; MaybeUninit, sym::maybe_uninit, maybe_uninit, Target::Union, GenericRequirement::None; /// Align offset for stride != 1; must not panic. AlignOffset, sym::align_offset, align_offset_fn, Target::Fn, GenericRequirement::None; Termination, sym::termination, termination, Target::Trait, GenericRequirement::None; Try, sym::Try, try_trait, Target::Trait, GenericRequirement::None; Tuple, sym::tuple_trait, tuple_trait, Target::Trait, GenericRequirement::Exact(0); SliceLen, sym::slice_len_fn, slice_len_fn, Target::Method(MethodKind::Inherent), GenericRequirement::None; // Language items from AST lowering TryTraitFromResidual, sym::from_residual, from_residual_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; TryTraitFromOutput, sym::from_output, from_output_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; TryTraitBranch, sym::branch, branch_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; TryTraitFromYeet, sym::from_yeet, from_yeet_fn, Target::Fn, GenericRequirement::None; PointerLike, sym::pointer_like, pointer_like, Target::Trait, GenericRequirement::Exact(0); ConstParamTy, sym::const_param_ty, const_param_ty_trait, Target::Trait, GenericRequirement::Exact(0); Poll, sym::Poll, poll, Target::Enum, GenericRequirement::None; PollReady, sym::Ready, poll_ready_variant, Target::Variant, GenericRequirement::None; PollPending, sym::Pending, poll_pending_variant, Target::Variant, GenericRequirement::None; // FIXME(swatinem): the following lang items are used for async lowering and // should become obsolete eventually. ResumeTy, sym::ResumeTy, resume_ty, Target::Struct, GenericRequirement::None; GetContext, sym::get_context, get_context_fn, Target::Fn, GenericRequirement::None; Context, sym::Context, context, Target::Struct, GenericRequirement::None; FuturePoll, sym::poll, future_poll_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; Option, sym::Option, option_type, Target::Enum, GenericRequirement::None; OptionSome, sym::Some, option_some_variant, Target::Variant, GenericRequirement::None; OptionNone, sym::None, option_none_variant, Target::Variant, GenericRequirement::None; ResultOk, sym::Ok, result_ok_variant, Target::Variant, GenericRequirement::None; ResultErr, sym::Err, result_err_variant, Target::Variant, GenericRequirement::None; ControlFlowContinue, sym::Continue, cf_continue_variant, Target::Variant, GenericRequirement::None; ControlFlowBreak, sym::Break, cf_break_variant, Target::Variant, GenericRequirement::None; IntoFutureIntoFuture, sym::into_future, into_future_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; IntoIterIntoIter, sym::into_iter, into_iter_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; IteratorNext, sym::next, next_fn, Target::Method(MethodKind::Trait { body: false}), GenericRequirement::None; PinNewUnchecked, sym::new_unchecked, new_unchecked_fn, Target::Method(MethodKind::Inherent), GenericRequirement::None; RangeFrom, sym::RangeFrom, range_from_struct, Target::Struct, GenericRequirement::None; RangeFull, sym::RangeFull, range_full_struct, Target::Struct, GenericRequirement::None; RangeInclusiveStruct, sym::RangeInclusive, range_inclusive_struct, Target::Struct, GenericRequirement::None; RangeInclusiveNew, sym::range_inclusive_new, range_inclusive_new_method, Target::Method(MethodKind::Inherent), GenericRequirement::None; Range, sym::Range, range_struct, Target::Struct, GenericRequirement::None; RangeToInclusive, sym::RangeToInclusive, range_to_inclusive_struct, Target::Struct, GenericRequirement::None; RangeTo, sym::RangeTo, range_to_struct, Target::Struct, GenericRequirement::None; String, sym::String, string, Target::Struct, GenericRequirement::None; CStr, sym::CStr, c_str, Target::Struct, GenericRequirement::None; }