| //! A pass that annotates every item and method with its stability level, |
| //! propagating default levels lexically from parent to children ast nodes. |
| |
| use rustc_ast::ast::Attribute; |
| use rustc_attr::{self as attr, ConstStability, Stability}; |
| use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
| use rustc_errors::struct_span_err; |
| use rustc_hir as hir; |
| use rustc_hir::def::{DefKind, Res}; |
| use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE}; |
| use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor}; |
| use rustc_hir::{Generics, HirId, Item, StructField, Variant}; |
| use rustc_middle::hir::map::Map; |
| use rustc_middle::middle::privacy::AccessLevels; |
| use rustc_middle::middle::stability::{DeprecationEntry, Index}; |
| use rustc_middle::ty::query::Providers; |
| use rustc_middle::ty::TyCtxt; |
| use rustc_session::lint; |
| use rustc_session::parse::feature_err; |
| use rustc_session::Session; |
| use rustc_span::symbol::{sym, Symbol}; |
| use rustc_span::Span; |
| use rustc_trait_selection::traits::misc::can_type_implement_copy; |
| |
| use std::cmp::Ordering; |
| use std::mem::replace; |
| use std::num::NonZeroU32; |
| |
| #[derive(PartialEq)] |
| enum AnnotationKind { |
| // Annotation is required if not inherited from unstable parents |
| Required, |
| // Annotation is useless, reject it |
| Prohibited, |
| // Annotation itself is useless, but it can be propagated to children |
| Container, |
| } |
| |
| // A private tree-walker for producing an Index. |
| struct Annotator<'a, 'tcx> { |
| tcx: TyCtxt<'tcx>, |
| index: &'a mut Index<'tcx>, |
| parent_stab: Option<&'tcx Stability>, |
| parent_const_stab: Option<&'tcx ConstStability>, |
| parent_depr: Option<DeprecationEntry>, |
| in_trait_impl: bool, |
| } |
| |
| impl<'a, 'tcx> Annotator<'a, 'tcx> { |
| // Determine the stability for a node based on its attributes and inherited |
| // stability. The stability is recorded in the index and used as the parent. |
| fn annotate<F>( |
| &mut self, |
| hir_id: HirId, |
| attrs: &[Attribute], |
| item_sp: Span, |
| kind: AnnotationKind, |
| visit_children: F, |
| ) where |
| F: FnOnce(&mut Self), |
| { |
| if !self.tcx.features().staged_api { |
| self.forbid_staged_api_attrs(hir_id, attrs, item_sp, kind, visit_children); |
| return; |
| } |
| |
| // This crate explicitly wants staged API. |
| |
| debug!("annotate(id = {:?}, attrs = {:?})", hir_id, attrs); |
| if let Some(..) = attr::find_deprecation(&self.tcx.sess.parse_sess, attrs, item_sp) { |
| self.tcx.sess.span_err( |
| item_sp, |
| "`#[deprecated]` cannot be used in staged API; \ |
| use `#[rustc_deprecated]` instead", |
| ); |
| } |
| |
| let (stab, const_stab) = attr::find_stability(&self.tcx.sess.parse_sess, attrs, item_sp); |
| |
| let const_stab = const_stab.map(|const_stab| { |
| let const_stab = self.tcx.intern_const_stability(const_stab); |
| self.index.const_stab_map.insert(hir_id, const_stab); |
| const_stab |
| }); |
| |
| if const_stab.is_none() { |
| debug!("annotate: const_stab not found, parent = {:?}", self.parent_const_stab); |
| if let Some(parent) = self.parent_const_stab { |
| if parent.level.is_unstable() { |
| self.index.const_stab_map.insert(hir_id, parent); |
| } |
| } |
| } |
| |
| let stab = stab.map(|mut stab| { |
| // Error if prohibited, or can't inherit anything from a container. |
| if kind == AnnotationKind::Prohibited |
| || (kind == AnnotationKind::Container |
| && stab.level.is_stable() |
| && stab.rustc_depr.is_none()) |
| { |
| self.tcx.sess.span_err(item_sp, "This stability annotation is useless"); |
| } |
| |
| debug!("annotate: found {:?}", stab); |
| // If parent is deprecated and we're not, inherit this by merging |
| // deprecated_since and its reason. |
| if let Some(parent_stab) = self.parent_stab { |
| if parent_stab.rustc_depr.is_some() && stab.rustc_depr.is_none() { |
| stab.rustc_depr = parent_stab.rustc_depr |
| } |
| } |
| |
| let stab = self.tcx.intern_stability(stab); |
| |
| // Check if deprecated_since < stable_since. If it is, |
| // this is *almost surely* an accident. |
| if let ( |
| &Some(attr::RustcDeprecation { since: dep_since, .. }), |
| &attr::Stable { since: stab_since }, |
| ) = (&stab.rustc_depr, &stab.level) |
| { |
| // Explicit version of iter::order::lt to handle parse errors properly |
| for (dep_v, stab_v) in |
| dep_since.as_str().split('.').zip(stab_since.as_str().split('.')) |
| { |
| if let (Ok(dep_v), Ok(stab_v)) = (dep_v.parse::<u64>(), stab_v.parse()) { |
| match dep_v.cmp(&stab_v) { |
| Ordering::Less => { |
| self.tcx.sess.span_err( |
| item_sp, |
| "An API can't be stabilized \ |
| after it is deprecated", |
| ); |
| break; |
| } |
| Ordering::Equal => continue, |
| Ordering::Greater => break, |
| } |
| } else { |
| // Act like it isn't less because the question is now nonsensical, |
| // and this makes us not do anything else interesting. |
| self.tcx.sess.span_err( |
| item_sp, |
| "Invalid stability or deprecation \ |
| version found", |
| ); |
| break; |
| } |
| } |
| } |
| |
| self.index.stab_map.insert(hir_id, stab); |
| stab |
| }); |
| |
| if stab.is_none() { |
| debug!("annotate: stab not found, parent = {:?}", self.parent_stab); |
| if let Some(stab) = self.parent_stab { |
| if stab.level.is_unstable() { |
| self.index.stab_map.insert(hir_id, stab); |
| } |
| } |
| } |
| |
| self.recurse_with_stability_attrs(stab, const_stab, visit_children); |
| } |
| |
| fn recurse_with_stability_attrs( |
| &mut self, |
| stab: Option<&'tcx Stability>, |
| const_stab: Option<&'tcx ConstStability>, |
| f: impl FnOnce(&mut Self), |
| ) { |
| // These will be `Some` if this item changes the corresponding stability attribute. |
| let mut replaced_parent_stab = None; |
| let mut replaced_parent_const_stab = None; |
| |
| if let Some(stab) = stab { |
| replaced_parent_stab = Some(replace(&mut self.parent_stab, Some(stab))); |
| } |
| if let Some(const_stab) = const_stab { |
| replaced_parent_const_stab = |
| Some(replace(&mut self.parent_const_stab, Some(const_stab))); |
| } |
| |
| f(self); |
| |
| if let Some(orig_parent_stab) = replaced_parent_stab { |
| self.parent_stab = orig_parent_stab; |
| } |
| if let Some(orig_parent_const_stab) = replaced_parent_const_stab { |
| self.parent_const_stab = orig_parent_const_stab; |
| } |
| } |
| |
| fn forbid_staged_api_attrs( |
| &mut self, |
| hir_id: HirId, |
| attrs: &[Attribute], |
| item_sp: Span, |
| kind: AnnotationKind, |
| visit_children: impl FnOnce(&mut Self), |
| ) { |
| // Emit errors for non-staged-api crates. |
| let unstable_attrs = [ |
| sym::unstable, |
| sym::stable, |
| sym::rustc_deprecated, |
| sym::rustc_const_unstable, |
| sym::rustc_const_stable, |
| ]; |
| for attr in attrs { |
| let name = attr.name_or_empty(); |
| if unstable_attrs.contains(&name) { |
| attr::mark_used(attr); |
| struct_span_err!( |
| self.tcx.sess, |
| attr.span, |
| E0734, |
| "stability attributes may not be used outside of the standard library", |
| ) |
| .emit(); |
| } |
| } |
| |
| // Propagate unstability. This can happen even for non-staged-api crates in case |
| // -Zforce-unstable-if-unmarked is set. |
| if let Some(stab) = self.parent_stab { |
| if stab.level.is_unstable() { |
| self.index.stab_map.insert(hir_id, stab); |
| } |
| } |
| |
| if let Some(depr) = attr::find_deprecation(&self.tcx.sess.parse_sess, attrs, item_sp) { |
| if kind == AnnotationKind::Prohibited { |
| self.tcx.sess.span_err(item_sp, "This deprecation annotation is useless"); |
| } |
| |
| // `Deprecation` is just two pointers, no need to intern it |
| let depr_entry = DeprecationEntry::local(depr, hir_id); |
| self.index.depr_map.insert(hir_id, depr_entry.clone()); |
| |
| let orig_parent_depr = replace(&mut self.parent_depr, Some(depr_entry)); |
| visit_children(self); |
| self.parent_depr = orig_parent_depr; |
| } else if let Some(parent_depr) = self.parent_depr.clone() { |
| self.index.depr_map.insert(hir_id, parent_depr); |
| visit_children(self); |
| } else { |
| visit_children(self); |
| } |
| } |
| } |
| |
| impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> { |
| /// Because stability levels are scoped lexically, we want to walk |
| /// nested items in the context of the outer item, so enable |
| /// deep-walking. |
| type Map = Map<'tcx>; |
| |
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { |
| NestedVisitorMap::All(self.tcx.hir()) |
| } |
| |
| fn visit_item(&mut self, i: &'tcx Item<'tcx>) { |
| let orig_in_trait_impl = self.in_trait_impl; |
| let mut kind = AnnotationKind::Required; |
| match i.kind { |
| // Inherent impls and foreign modules serve only as containers for other items, |
| // they don't have their own stability. They still can be annotated as unstable |
| // and propagate this unstability to children, but this annotation is completely |
| // optional. They inherit stability from their parents when unannotated. |
| hir::ItemKind::Impl { of_trait: None, .. } | hir::ItemKind::ForeignMod(..) => { |
| self.in_trait_impl = false; |
| kind = AnnotationKind::Container; |
| } |
| hir::ItemKind::Impl { of_trait: Some(_), .. } => { |
| self.in_trait_impl = true; |
| } |
| hir::ItemKind::Struct(ref sd, _) => { |
| if let Some(ctor_hir_id) = sd.ctor_hir_id() { |
| self.annotate(ctor_hir_id, &i.attrs, i.span, AnnotationKind::Required, |_| {}) |
| } |
| } |
| _ => {} |
| } |
| |
| self.annotate(i.hir_id, &i.attrs, i.span, kind, |v| intravisit::walk_item(v, i)); |
| self.in_trait_impl = orig_in_trait_impl; |
| } |
| |
| fn visit_trait_item(&mut self, ti: &'tcx hir::TraitItem<'tcx>) { |
| self.annotate(ti.hir_id, &ti.attrs, ti.span, AnnotationKind::Required, |v| { |
| intravisit::walk_trait_item(v, ti); |
| }); |
| } |
| |
| fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem<'tcx>) { |
| let kind = |
| if self.in_trait_impl { AnnotationKind::Prohibited } else { AnnotationKind::Required }; |
| self.annotate(ii.hir_id, &ii.attrs, ii.span, kind, |v| { |
| intravisit::walk_impl_item(v, ii); |
| }); |
| } |
| |
| fn visit_variant(&mut self, var: &'tcx Variant<'tcx>, g: &'tcx Generics<'tcx>, item_id: HirId) { |
| self.annotate(var.id, &var.attrs, var.span, AnnotationKind::Required, |v| { |
| if let Some(ctor_hir_id) = var.data.ctor_hir_id() { |
| v.annotate(ctor_hir_id, &var.attrs, var.span, AnnotationKind::Required, |_| {}); |
| } |
| |
| intravisit::walk_variant(v, var, g, item_id) |
| }) |
| } |
| |
| fn visit_struct_field(&mut self, s: &'tcx StructField<'tcx>) { |
| self.annotate(s.hir_id, &s.attrs, s.span, AnnotationKind::Required, |v| { |
| intravisit::walk_struct_field(v, s); |
| }); |
| } |
| |
| fn visit_foreign_item(&mut self, i: &'tcx hir::ForeignItem<'tcx>) { |
| self.annotate(i.hir_id, &i.attrs, i.span, AnnotationKind::Required, |v| { |
| intravisit::walk_foreign_item(v, i); |
| }); |
| } |
| |
| fn visit_macro_def(&mut self, md: &'tcx hir::MacroDef<'tcx>) { |
| self.annotate(md.hir_id, &md.attrs, md.span, AnnotationKind::Required, |_| {}); |
| } |
| } |
| |
| struct MissingStabilityAnnotations<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| access_levels: &'tcx AccessLevels, |
| } |
| |
| impl<'tcx> MissingStabilityAnnotations<'tcx> { |
| fn check_missing_stability(&self, hir_id: HirId, span: Span) { |
| let stab = self.tcx.stability().local_stability(hir_id); |
| let is_error = |
| !self.tcx.sess.opts.test && stab.is_none() && self.access_levels.is_reachable(hir_id); |
| if is_error { |
| let def_id = self.tcx.hir().local_def_id(hir_id); |
| let descr = self.tcx.def_kind(def_id).descr(def_id.to_def_id()); |
| self.tcx.sess.span_err(span, &format!("{} has missing stability attribute", descr)); |
| } |
| } |
| } |
| |
| impl<'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'tcx> { |
| type Map = Map<'tcx>; |
| |
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { |
| NestedVisitorMap::OnlyBodies(self.tcx.hir()) |
| } |
| |
| fn visit_item(&mut self, i: &'tcx Item<'tcx>) { |
| match i.kind { |
| // Inherent impls and foreign modules serve only as containers for other items, |
| // they don't have their own stability. They still can be annotated as unstable |
| // and propagate this unstability to children, but this annotation is completely |
| // optional. They inherit stability from their parents when unannotated. |
| hir::ItemKind::Impl { of_trait: None, .. } | hir::ItemKind::ForeignMod(..) => {} |
| |
| _ => self.check_missing_stability(i.hir_id, i.span), |
| } |
| |
| intravisit::walk_item(self, i) |
| } |
| |
| fn visit_trait_item(&mut self, ti: &'tcx hir::TraitItem<'tcx>) { |
| self.check_missing_stability(ti.hir_id, ti.span); |
| intravisit::walk_trait_item(self, ti); |
| } |
| |
| fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem<'tcx>) { |
| let impl_def_id = self.tcx.hir().local_def_id(self.tcx.hir().get_parent_item(ii.hir_id)); |
| if self.tcx.impl_trait_ref(impl_def_id).is_none() { |
| self.check_missing_stability(ii.hir_id, ii.span); |
| } |
| intravisit::walk_impl_item(self, ii); |
| } |
| |
| fn visit_variant(&mut self, var: &'tcx Variant<'tcx>, g: &'tcx Generics<'tcx>, item_id: HirId) { |
| self.check_missing_stability(var.id, var.span); |
| intravisit::walk_variant(self, var, g, item_id); |
| } |
| |
| fn visit_struct_field(&mut self, s: &'tcx StructField<'tcx>) { |
| self.check_missing_stability(s.hir_id, s.span); |
| intravisit::walk_struct_field(self, s); |
| } |
| |
| fn visit_foreign_item(&mut self, i: &'tcx hir::ForeignItem<'tcx>) { |
| self.check_missing_stability(i.hir_id, i.span); |
| intravisit::walk_foreign_item(self, i); |
| } |
| |
| fn visit_macro_def(&mut self, md: &'tcx hir::MacroDef<'tcx>) { |
| self.check_missing_stability(md.hir_id, md.span); |
| } |
| } |
| |
| fn new_index(tcx: TyCtxt<'tcx>) -> Index<'tcx> { |
| let is_staged_api = |
| tcx.sess.opts.debugging_opts.force_unstable_if_unmarked || tcx.features().staged_api; |
| let mut staged_api = FxHashMap::default(); |
| staged_api.insert(LOCAL_CRATE, is_staged_api); |
| let mut index = Index { |
| staged_api, |
| stab_map: Default::default(), |
| const_stab_map: Default::default(), |
| depr_map: Default::default(), |
| active_features: Default::default(), |
| }; |
| |
| let active_lib_features = &tcx.features().declared_lib_features; |
| let active_lang_features = &tcx.features().declared_lang_features; |
| |
| // Put the active features into a map for quick lookup. |
| index.active_features = active_lib_features |
| .iter() |
| .map(|&(s, ..)| s) |
| .chain(active_lang_features.iter().map(|&(s, ..)| s)) |
| .collect(); |
| |
| { |
| let krate = tcx.hir().krate(); |
| let mut annotator = Annotator { |
| tcx, |
| index: &mut index, |
| parent_stab: None, |
| parent_const_stab: None, |
| parent_depr: None, |
| in_trait_impl: false, |
| }; |
| |
| // If the `-Z force-unstable-if-unmarked` flag is passed then we provide |
| // a parent stability annotation which indicates that this is private |
| // with the `rustc_private` feature. This is intended for use when |
| // compiling `librustc_*` crates themselves so we can leverage crates.io |
| // while maintaining the invariant that all sysroot crates are unstable |
| // by default and are unable to be used. |
| if tcx.sess.opts.debugging_opts.force_unstable_if_unmarked { |
| let reason = "this crate is being loaded from the sysroot, an \ |
| unstable location; did you mean to load this crate \ |
| from crates.io via `Cargo.toml` instead?"; |
| let stability = tcx.intern_stability(Stability { |
| level: attr::StabilityLevel::Unstable { |
| reason: Some(Symbol::intern(reason)), |
| issue: NonZeroU32::new(27812), |
| is_soft: false, |
| }, |
| feature: sym::rustc_private, |
| rustc_depr: None, |
| }); |
| annotator.parent_stab = Some(stability); |
| } |
| |
| annotator.annotate( |
| hir::CRATE_HIR_ID, |
| &krate.item.attrs, |
| krate.item.span, |
| AnnotationKind::Required, |
| |v| intravisit::walk_crate(v, krate), |
| ); |
| } |
| index |
| } |
| |
| /// Cross-references the feature names of unstable APIs with enabled |
| /// features and possibly prints errors. |
| fn check_mod_unstable_api_usage(tcx: TyCtxt<'_>, module_def_id: LocalDefId) { |
| tcx.hir().visit_item_likes_in_module(module_def_id, &mut Checker { tcx }.as_deep_visitor()); |
| } |
| |
| pub(crate) fn provide(providers: &mut Providers) { |
| *providers = Providers { check_mod_unstable_api_usage, ..*providers }; |
| providers.stability_index = |tcx, cnum| { |
| assert_eq!(cnum, LOCAL_CRATE); |
| new_index(tcx) |
| }; |
| } |
| |
| struct Checker<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| } |
| |
| impl Visitor<'tcx> for Checker<'tcx> { |
| type Map = Map<'tcx>; |
| |
| /// Because stability levels are scoped lexically, we want to walk |
| /// nested items in the context of the outer item, so enable |
| /// deep-walking. |
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { |
| NestedVisitorMap::OnlyBodies(self.tcx.hir()) |
| } |
| |
| fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) { |
| match item.kind { |
| hir::ItemKind::ExternCrate(_) => { |
| // compiler-generated `extern crate` items have a dummy span. |
| if item.span.is_dummy() { |
| return; |
| } |
| |
| let def_id = self.tcx.hir().local_def_id(item.hir_id); |
| let cnum = match self.tcx.extern_mod_stmt_cnum(def_id) { |
| Some(cnum) => cnum, |
| None => return, |
| }; |
| let def_id = DefId { krate: cnum, index: CRATE_DEF_INDEX }; |
| self.tcx.check_stability(def_id, Some(item.hir_id), item.span); |
| } |
| |
| // For implementations of traits, check the stability of each item |
| // individually as it's possible to have a stable trait with unstable |
| // items. |
| hir::ItemKind::Impl { of_trait: Some(ref t), items, .. } => { |
| if let Res::Def(DefKind::Trait, trait_did) = t.path.res { |
| for impl_item_ref in items { |
| let impl_item = self.tcx.hir().impl_item(impl_item_ref.id); |
| let trait_item_def_id = self |
| .tcx |
| .associated_items(trait_did) |
| .filter_by_name_unhygienic(impl_item.ident.name) |
| .next() |
| .map(|item| item.def_id); |
| if let Some(def_id) = trait_item_def_id { |
| // Pass `None` to skip deprecation warnings. |
| self.tcx.check_stability(def_id, None, impl_item.span); |
| } |
| } |
| } |
| } |
| |
| // There's no good place to insert stability check for non-Copy unions, |
| // so semi-randomly perform it here in stability.rs |
| hir::ItemKind::Union(..) if !self.tcx.features().untagged_unions => { |
| let def_id = self.tcx.hir().local_def_id(item.hir_id); |
| let adt_def = self.tcx.adt_def(def_id); |
| let ty = self.tcx.type_of(def_id); |
| |
| if adt_def.has_dtor(self.tcx) { |
| feature_err( |
| &self.tcx.sess.parse_sess, |
| sym::untagged_unions, |
| item.span, |
| "unions with `Drop` implementations are unstable", |
| ) |
| .emit(); |
| } else { |
| let param_env = self.tcx.param_env(def_id); |
| if can_type_implement_copy(self.tcx, param_env, ty).is_err() { |
| feature_err( |
| &self.tcx.sess.parse_sess, |
| sym::untagged_unions, |
| item.span, |
| "unions with non-`Copy` fields are unstable", |
| ) |
| .emit(); |
| } |
| } |
| } |
| |
| _ => (/* pass */), |
| } |
| intravisit::walk_item(self, item); |
| } |
| |
| fn visit_path(&mut self, path: &'tcx hir::Path<'tcx>, id: hir::HirId) { |
| if let Some(def_id) = path.res.opt_def_id() { |
| self.tcx.check_stability(def_id, Some(id), path.span) |
| } |
| intravisit::walk_path(self, path) |
| } |
| } |
| |
| /// Given the list of enabled features that were not language features (i.e., that |
| /// were expected to be library features), and the list of features used from |
| /// libraries, identify activated features that don't exist and error about them. |
| pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) { |
| let access_levels = &tcx.privacy_access_levels(LOCAL_CRATE); |
| |
| if tcx.stability().staged_api[&LOCAL_CRATE] { |
| let krate = tcx.hir().krate(); |
| let mut missing = MissingStabilityAnnotations { tcx, access_levels }; |
| missing.check_missing_stability(hir::CRATE_HIR_ID, krate.item.span); |
| intravisit::walk_crate(&mut missing, krate); |
| krate.visit_all_item_likes(&mut missing.as_deep_visitor()); |
| } |
| |
| let declared_lang_features = &tcx.features().declared_lang_features; |
| let mut lang_features = FxHashSet::default(); |
| for &(feature, span, since) in declared_lang_features { |
| if let Some(since) = since { |
| // Warn if the user has enabled an already-stable lang feature. |
| unnecessary_stable_feature_lint(tcx, span, feature, since); |
| } |
| if !lang_features.insert(feature) { |
| // Warn if the user enables a lang feature multiple times. |
| duplicate_feature_err(tcx.sess, span, feature); |
| } |
| } |
| |
| let declared_lib_features = &tcx.features().declared_lib_features; |
| let mut remaining_lib_features = FxHashMap::default(); |
| for (feature, span) in declared_lib_features { |
| if remaining_lib_features.contains_key(&feature) { |
| // Warn if the user enables a lib feature multiple times. |
| duplicate_feature_err(tcx.sess, *span, *feature); |
| } |
| remaining_lib_features.insert(feature, *span); |
| } |
| // `stdbuild` has special handling for `libc`, so we need to |
| // recognise the feature when building std. |
| // Likewise, libtest is handled specially, so `test` isn't |
| // available as we'd like it to be. |
| // FIXME: only remove `libc` when `stdbuild` is active. |
| // FIXME: remove special casing for `test`. |
| remaining_lib_features.remove(&Symbol::intern("libc")); |
| remaining_lib_features.remove(&sym::test); |
| |
| let check_features = |remaining_lib_features: &mut FxHashMap<_, _>, defined_features: &[_]| { |
| for &(feature, since) in defined_features { |
| if let Some(since) = since { |
| if let Some(span) = remaining_lib_features.get(&feature) { |
| // Warn if the user has enabled an already-stable lib feature. |
| unnecessary_stable_feature_lint(tcx, *span, feature, since); |
| } |
| } |
| remaining_lib_features.remove(&feature); |
| if remaining_lib_features.is_empty() { |
| break; |
| } |
| } |
| }; |
| |
| // We always collect the lib features declared in the current crate, even if there are |
| // no unknown features, because the collection also does feature attribute validation. |
| let local_defined_features = tcx.lib_features().to_vec(); |
| if !remaining_lib_features.is_empty() { |
| check_features(&mut remaining_lib_features, &local_defined_features); |
| |
| for &cnum in &*tcx.crates() { |
| if remaining_lib_features.is_empty() { |
| break; |
| } |
| check_features(&mut remaining_lib_features, tcx.defined_lib_features(cnum)); |
| } |
| } |
| |
| for (feature, span) in remaining_lib_features { |
| struct_span_err!(tcx.sess, span, E0635, "unknown feature `{}`", feature).emit(); |
| } |
| |
| // FIXME(#44232): the `used_features` table no longer exists, so we |
| // don't lint about unused features. We should re-enable this one day! |
| } |
| |
| fn unnecessary_stable_feature_lint(tcx: TyCtxt<'_>, span: Span, feature: Symbol, since: Symbol) { |
| tcx.struct_span_lint_hir(lint::builtin::STABLE_FEATURES, hir::CRATE_HIR_ID, span, |lint| { |
| lint.build(&format!( |
| "the feature `{}` has been stable since {} and no longer requires \ |
| an attribute to enable", |
| feature, since |
| )) |
| .emit(); |
| }); |
| } |
| |
| fn duplicate_feature_err(sess: &Session, span: Span, feature: Symbol) { |
| struct_span_err!(sess, span, E0636, "the feature `{}` has already been declared", feature) |
| .emit(); |
| } |
