1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! A pass that annotates every item and method with its stability level,
12 //! propagating default levels lexically from parent to children ast nodes.
14 pub use self::StabilityLevel::*;
18 use hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefId, LOCAL_CRATE};
19 use ty::{self, TyCtxt};
20 use middle::privacy::AccessLevels;
21 use session::{DiagnosticMessageId, Session};
22 use syntax::symbol::Symbol;
23 use syntax_pos::{Span, MultiSpan};
25 use syntax::ast::{NodeId, Attribute};
26 use syntax::feature_gate::{GateIssue, emit_feature_err};
27 use syntax::attr::{self, Stability, Deprecation};
28 use util::nodemap::{FxHashSet, FxHashMap};
31 use hir::{Item, Generics, StructField, Variant, HirId};
32 use hir::intravisit::{self, Visitor, NestedVisitorMap};
34 use std::mem::replace;
35 use std::cmp::Ordering;
37 #[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Copy, Debug, Eq, Hash)]
38 pub enum StabilityLevel {
44 pub fn from_attr_level(level: &attr::StabilityLevel) -> Self {
45 if level.is_stable() { Stable } else { Unstable }
51 // Annotation is required if not inherited from unstable parents
53 // Annotation is useless, reject it
55 // Annotation itself is useless, but it can be propagated to children
59 /// An entry in the `depr_map`.
61 pub struct DeprecationEntry {
62 /// The metadata of the attribute associated with this entry.
63 pub attr: Deprecation,
64 /// The def id where the attr was originally attached. `None` for non-local
66 origin: Option<HirId>,
69 impl_stable_hash_for!(struct self::DeprecationEntry {
74 impl DeprecationEntry {
75 fn local(attr: Deprecation, id: HirId) -> DeprecationEntry {
82 pub fn external(attr: Deprecation) -> DeprecationEntry {
89 pub fn same_origin(&self, other: &DeprecationEntry) -> bool {
90 match (self.origin, other.origin) {
91 (Some(o1), Some(o2)) => o1 == o2,
97 /// A stability index, giving the stability level for items and methods.
98 pub struct Index<'tcx> {
99 /// This is mostly a cache, except the stabilities of local items
100 /// are filled by the annotator.
101 stab_map: FxHashMap<HirId, &'tcx Stability>,
102 depr_map: FxHashMap<HirId, DeprecationEntry>,
104 /// Maps for each crate whether it is part of the staged API.
105 staged_api: FxHashMap<CrateNum, bool>,
107 /// Features enabled for this crate.
108 active_features: FxHashSet<Symbol>,
111 impl_stable_hash_for!(struct self::Index<'tcx> {
118 // A private tree-walker for producing an Index.
119 struct Annotator<'a, 'tcx: 'a> {
120 tcx: TyCtxt<'a, 'tcx, 'tcx>,
121 index: &'a mut Index<'tcx>,
122 parent_stab: Option<&'tcx Stability>,
123 parent_depr: Option<DeprecationEntry>,
127 impl<'a, 'tcx: 'a> Annotator<'a, 'tcx> {
128 // Determine the stability for a node based on its attributes and inherited
129 // stability. The stability is recorded in the index and used as the parent.
130 fn annotate<F>(&mut self, id: NodeId, attrs: &[Attribute],
131 item_sp: Span, kind: AnnotationKind, visit_children: F)
132 where F: FnOnce(&mut Self)
134 if self.tcx.features().staged_api {
135 // This crate explicitly wants staged API.
136 debug!("annotate(id = {:?}, attrs = {:?})", id, attrs);
137 if let Some(..) = attr::find_deprecation(self.tcx.sess.diagnostic(), attrs, item_sp) {
138 self.tcx.sess.span_err(item_sp, "`#[deprecated]` cannot be used in staged api, \
139 use `#[rustc_deprecated]` instead");
141 if let Some(mut stab) = attr::find_stability(self.tcx.sess.diagnostic(),
143 // Error if prohibited, or can't inherit anything from a container
144 if kind == AnnotationKind::Prohibited ||
145 (kind == AnnotationKind::Container &&
146 stab.level.is_stable() &&
147 stab.rustc_depr.is_none()) {
148 self.tcx.sess.span_err(item_sp, "This stability annotation is useless");
151 debug!("annotate: found {:?}", stab);
152 // If parent is deprecated and we're not, inherit this by merging
153 // deprecated_since and its reason.
154 if let Some(parent_stab) = self.parent_stab {
155 if parent_stab.rustc_depr.is_some() && stab.rustc_depr.is_none() {
156 stab.rustc_depr = parent_stab.rustc_depr.clone()
160 let stab = self.tcx.intern_stability(stab);
162 // Check if deprecated_since < stable_since. If it is,
163 // this is *almost surely* an accident.
164 if let (&Some(attr::RustcDeprecation {since: dep_since, ..}),
165 &attr::Stable {since: stab_since}) = (&stab.rustc_depr, &stab.level) {
166 // Explicit version of iter::order::lt to handle parse errors properly
167 for (dep_v, stab_v) in dep_since.as_str()
169 .zip(stab_since.as_str().split('.'))
171 if let (Ok(dep_v), Ok(stab_v)) = (dep_v.parse::<u64>(), stab_v.parse()) {
172 match dep_v.cmp(&stab_v) {
174 self.tcx.sess.span_err(item_sp, "An API can't be stabilized \
175 after it is deprecated");
178 Ordering::Equal => continue,
179 Ordering::Greater => break,
182 // Act like it isn't less because the question is now nonsensical,
183 // and this makes us not do anything else interesting.
184 self.tcx.sess.span_err(item_sp, "Invalid stability or deprecation \
191 let hir_id = self.tcx.hir.node_to_hir_id(id);
192 self.index.stab_map.insert(hir_id, stab);
194 let orig_parent_stab = replace(&mut self.parent_stab, Some(stab));
195 visit_children(self);
196 self.parent_stab = orig_parent_stab;
198 debug!("annotate: not found, parent = {:?}", self.parent_stab);
199 if let Some(stab) = self.parent_stab {
200 if stab.level.is_unstable() {
201 let hir_id = self.tcx.hir.node_to_hir_id(id);
202 self.index.stab_map.insert(hir_id, stab);
205 visit_children(self);
208 // Emit errors for non-staged-api crates.
210 let tag = attr.name();
211 if tag == "unstable" || tag == "stable" || tag == "rustc_deprecated" {
212 attr::mark_used(attr);
213 self.tcx.sess.span_err(attr.span(), "stability attributes may not be used \
214 outside of the standard library");
218 // Propagate unstability. This can happen even for non-staged-api crates in case
219 // -Zforce-unstable-if-unmarked is set.
220 if let Some(stab) = self.parent_stab {
221 if stab.level.is_unstable() {
222 let hir_id = self.tcx.hir.node_to_hir_id(id);
223 self.index.stab_map.insert(hir_id, stab);
227 if let Some(depr) = attr::find_deprecation(self.tcx.sess.diagnostic(), attrs, item_sp) {
228 if kind == AnnotationKind::Prohibited {
229 self.tcx.sess.span_err(item_sp, "This deprecation annotation is useless");
232 // `Deprecation` is just two pointers, no need to intern it
233 let hir_id = self.tcx.hir.node_to_hir_id(id);
234 let depr_entry = DeprecationEntry::local(depr, hir_id);
235 self.index.depr_map.insert(hir_id, depr_entry.clone());
237 let orig_parent_depr = replace(&mut self.parent_depr,
239 visit_children(self);
240 self.parent_depr = orig_parent_depr;
241 } else if let Some(parent_depr) = self.parent_depr.clone() {
242 let hir_id = self.tcx.hir.node_to_hir_id(id);
243 self.index.depr_map.insert(hir_id, parent_depr);
244 visit_children(self);
246 visit_children(self);
252 impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> {
253 /// Because stability levels are scoped lexically, we want to walk
254 /// nested items in the context of the outer item, so enable
256 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
257 NestedVisitorMap::All(&self.tcx.hir)
260 fn visit_item(&mut self, i: &'tcx Item) {
261 let orig_in_trait_impl = self.in_trait_impl;
262 let mut kind = AnnotationKind::Required;
264 // Inherent impls and foreign modules serve only as containers for other items,
265 // they don't have their own stability. They still can be annotated as unstable
266 // and propagate this unstability to children, but this annotation is completely
267 // optional. They inherit stability from their parents when unannotated.
268 hir::ItemKind::Impl(.., None, _, _) | hir::ItemKind::ForeignMod(..) => {
269 self.in_trait_impl = false;
270 kind = AnnotationKind::Container;
272 hir::ItemKind::Impl(.., Some(_), _, _) => {
273 self.in_trait_impl = true;
275 hir::ItemKind::Struct(ref sd, _) => {
277 self.annotate(sd.id(), &i.attrs, i.span, AnnotationKind::Required, |_| {})
283 self.annotate(i.id, &i.attrs, i.span, kind, |v| {
284 intravisit::walk_item(v, i)
286 self.in_trait_impl = orig_in_trait_impl;
289 fn visit_trait_item(&mut self, ti: &'tcx hir::TraitItem) {
290 self.annotate(ti.id, &ti.attrs, ti.span, AnnotationKind::Required, |v| {
291 intravisit::walk_trait_item(v, ti);
295 fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem) {
296 let kind = if self.in_trait_impl {
297 AnnotationKind::Prohibited
299 AnnotationKind::Required
301 self.annotate(ii.id, &ii.attrs, ii.span, kind, |v| {
302 intravisit::walk_impl_item(v, ii);
306 fn visit_variant(&mut self, var: &'tcx Variant, g: &'tcx Generics, item_id: NodeId) {
307 self.annotate(var.node.data.id(), &var.node.attrs, var.span, AnnotationKind::Required, |v| {
308 intravisit::walk_variant(v, var, g, item_id);
312 fn visit_struct_field(&mut self, s: &'tcx StructField) {
313 self.annotate(s.id, &s.attrs, s.span, AnnotationKind::Required, |v| {
314 intravisit::walk_struct_field(v, s);
318 fn visit_foreign_item(&mut self, i: &'tcx hir::ForeignItem) {
319 self.annotate(i.id, &i.attrs, i.span, AnnotationKind::Required, |v| {
320 intravisit::walk_foreign_item(v, i);
324 fn visit_macro_def(&mut self, md: &'tcx hir::MacroDef) {
325 self.annotate(md.id, &md.attrs, md.span, AnnotationKind::Required, |_| {});
329 struct MissingStabilityAnnotations<'a, 'tcx: 'a> {
330 tcx: TyCtxt<'a, 'tcx, 'tcx>,
331 access_levels: &'a AccessLevels,
334 impl<'a, 'tcx: 'a> MissingStabilityAnnotations<'a, 'tcx> {
335 fn check_missing_stability(&self, id: NodeId, span: Span) {
336 let hir_id = self.tcx.hir.node_to_hir_id(id);
337 let stab = self.tcx.stability().local_stability(hir_id);
338 let is_error = !self.tcx.sess.opts.test &&
340 self.access_levels.is_reachable(id);
342 self.tcx.sess.span_err(span, "This node does not have a stability attribute");
347 impl<'a, 'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'a, 'tcx> {
348 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
349 NestedVisitorMap::OnlyBodies(&self.tcx.hir)
352 fn visit_item(&mut self, i: &'tcx Item) {
354 // Inherent impls and foreign modules serve only as containers for other items,
355 // they don't have their own stability. They still can be annotated as unstable
356 // and propagate this unstability to children, but this annotation is completely
357 // optional. They inherit stability from their parents when unannotated.
358 hir::ItemKind::Impl(.., None, _, _) | hir::ItemKind::ForeignMod(..) => {}
360 _ => self.check_missing_stability(i.id, i.span)
363 intravisit::walk_item(self, i)
366 fn visit_trait_item(&mut self, ti: &'tcx hir::TraitItem) {
367 self.check_missing_stability(ti.id, ti.span);
368 intravisit::walk_trait_item(self, ti);
371 fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem) {
372 let impl_def_id = self.tcx.hir.local_def_id(self.tcx.hir.get_parent(ii.id));
373 if self.tcx.impl_trait_ref(impl_def_id).is_none() {
374 self.check_missing_stability(ii.id, ii.span);
376 intravisit::walk_impl_item(self, ii);
379 fn visit_variant(&mut self, var: &'tcx Variant, g: &'tcx Generics, item_id: NodeId) {
380 self.check_missing_stability(var.node.data.id(), var.span);
381 intravisit::walk_variant(self, var, g, item_id);
384 fn visit_struct_field(&mut self, s: &'tcx StructField) {
385 self.check_missing_stability(s.id, s.span);
386 intravisit::walk_struct_field(self, s);
389 fn visit_foreign_item(&mut self, i: &'tcx hir::ForeignItem) {
390 self.check_missing_stability(i.id, i.span);
391 intravisit::walk_foreign_item(self, i);
394 fn visit_macro_def(&mut self, md: &'tcx hir::MacroDef) {
395 self.check_missing_stability(md.id, md.span);
399 impl<'a, 'tcx> Index<'tcx> {
400 pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Index<'tcx> {
402 tcx.sess.opts.debugging_opts.force_unstable_if_unmarked ||
403 tcx.features().staged_api;
404 let mut staged_api = FxHashMap();
405 staged_api.insert(LOCAL_CRATE, is_staged_api);
406 let mut index = Index {
408 stab_map: FxHashMap(),
409 depr_map: FxHashMap(),
410 active_features: FxHashSet(),
413 let ref active_lib_features = tcx.features().declared_lib_features;
415 // Put the active features into a map for quick lookup
416 index.active_features = active_lib_features.iter().map(|&(ref s, _)| s.clone()).collect();
419 let krate = tcx.hir.krate();
420 let mut annotator = Annotator {
425 in_trait_impl: false,
428 // If the `-Z force-unstable-if-unmarked` flag is passed then we provide
429 // a parent stability annotation which indicates that this is private
430 // with the `rustc_private` feature. This is intended for use when
431 // compiling librustc crates themselves so we can leverage crates.io
432 // while maintaining the invariant that all sysroot crates are unstable
433 // by default and are unable to be used.
434 if tcx.sess.opts.debugging_opts.force_unstable_if_unmarked {
435 let reason = "this crate is being loaded from the sysroot, an \
436 unstable location; did you mean to load this crate \
437 from crates.io via `Cargo.toml` instead?";
438 let stability = tcx.intern_stability(Stability {
439 level: attr::StabilityLevel::Unstable {
440 reason: Some(Symbol::intern(reason)),
443 feature: Symbol::intern("rustc_private"),
445 const_stability: None,
448 annotator.parent_stab = Some(stability);
451 annotator.annotate(ast::CRATE_NODE_ID,
454 AnnotationKind::Required,
455 |v| intravisit::walk_crate(v, krate));
460 pub fn local_stability(&self, id: HirId) -> Option<&'tcx Stability> {
461 self.stab_map.get(&id).cloned()
464 pub fn local_deprecation_entry(&self, id: HirId) -> Option<DeprecationEntry> {
465 self.depr_map.get(&id).cloned()
469 /// Cross-references the feature names of unstable APIs with enabled
470 /// features and possibly prints errors.
471 pub fn check_unstable_api_usage<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
472 let mut checker = Checker { tcx: tcx };
473 tcx.hir.krate().visit_all_item_likes(&mut checker.as_deep_visitor());
476 /// Check whether an item marked with `deprecated(since="X")` is currently
477 /// deprecated (i.e. whether X is not greater than the current rustc version).
478 pub fn deprecation_in_effect(since: &str) -> bool {
479 fn parse_version(ver: &str) -> Vec<u32> {
480 // We ignore non-integer components of the version (e.g. "nightly").
481 ver.split(|c| c == '.' || c == '-').flat_map(|s| s.parse()).collect()
484 if let Some(rustc) = option_env!("CFG_RELEASE") {
485 let since: Vec<u32> = parse_version(since);
486 let rustc: Vec<u32> = parse_version(rustc);
487 // We simply treat invalid `since` attributes as relating to a previous
488 // Rust version, thus always displaying the warning.
489 if since.len() != 3 {
494 // By default, a deprecation warning applies to
495 // the current version of the compiler.
500 struct Checker<'a, 'tcx: 'a> {
501 tcx: TyCtxt<'a, 'tcx, 'tcx>,
504 /// Result of `TyCtxt::eval_stability`.
505 pub enum EvalResult {
506 /// We can use the item because it is stable or we provided the
507 /// corresponding feature gate.
509 /// We cannot use the item because it is unstable and we did not provide the
510 /// corresponding feature gate.
513 reason: Option<Symbol>,
516 /// The item does not have the `#[stable]` or `#[unstable]` marker assigned.
520 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
521 // (See issue #38412)
522 fn skip_stability_check_due_to_privacy(self, mut def_id: DefId) -> bool {
523 // Check if `def_id` is a trait method.
524 match self.describe_def(def_id) {
525 Some(Def::Method(_)) |
526 Some(Def::AssociatedTy(_)) |
527 Some(Def::AssociatedConst(_)) => {
528 if let ty::TraitContainer(trait_def_id) = self.associated_item(def_id).container {
529 // Trait methods do not declare visibility (even
530 // for visibility info in cstore). Use containing
531 // trait instead, so methods of pub traits are
532 // themselves considered pub.
533 def_id = trait_def_id;
539 let visibility = self.visibility(def_id);
542 // must check stability for pub items.
543 ty::Visibility::Public => false,
545 // these are not visible outside crate; therefore
546 // stability markers are irrelevant, if even present.
547 ty::Visibility::Restricted(..) |
548 ty::Visibility::Invisible => true,
552 /// Evaluates the stability of an item.
554 /// Returns `EvalResult::Allow` if the item is stable, or unstable but the corresponding
555 /// `#![feature]` has been provided. Returns `EvalResult::Deny` which describes the offending
556 /// unstable feature otherwise.
558 /// If `id` is `Some(_)`, this function will also check if the item at `def_id` has been
559 /// deprecated. If the item is indeed deprecated, we will emit a deprecation lint attached to
561 pub fn eval_stability(self, def_id: DefId, id: Option<NodeId>, span: Span) -> EvalResult {
562 if span.allows_unstable() {
563 debug!("stability: skipping span={:?} since it is internal", span);
564 return EvalResult::Allow;
567 let lint_deprecated = |def_id: DefId, id: NodeId, note: Option<Symbol>| {
568 let path = self.item_path_str(def_id);
570 let msg = if let Some(note) = note {
571 format!("use of deprecated item '{}': {}", path, note)
573 format!("use of deprecated item '{}'", path)
576 self.lint_node(lint::builtin::DEPRECATED, id, span, &msg);
577 if id == ast::DUMMY_NODE_ID {
578 span_bug!(span, "emitted a deprecated lint with dummy node id: {:?}", def_id);
582 // Deprecated attributes apply in-crate and cross-crate.
583 if let Some(id) = id {
584 if let Some(depr_entry) = self.lookup_deprecation_entry(def_id) {
585 // If the deprecation is scheduled for a future Rust
586 // version, then we should display no warning message.
587 let deprecated_in_future_version = if let Some(sym) = depr_entry.attr.since {
588 let since = sym.as_str();
589 !deprecation_in_effect(&since)
594 let parent_def_id = self.hir.local_def_id(self.hir.get_parent(id));
595 let skip = deprecated_in_future_version ||
596 self.lookup_deprecation_entry(parent_def_id)
597 .map_or(false, |parent_depr| parent_depr.same_origin(&depr_entry));
599 lint_deprecated(def_id, id, depr_entry.attr.note);
604 let is_staged_api = self.lookup_stability(DefId {
605 index: CRATE_DEF_INDEX,
609 return EvalResult::Allow;
612 let stability = self.lookup_stability(def_id);
614 inspecting def_id={:?} span={:?} of stability={:?}", def_id, span, stability);
616 if let Some(&Stability{rustc_depr: Some(attr::RustcDeprecation { reason, since }), ..})
618 if let Some(id) = id {
619 if deprecation_in_effect(&since.as_str()) {
620 lint_deprecated(def_id, id, Some(reason));
625 // Only the cross-crate scenario matters when checking unstable APIs
626 let cross_crate = !def_id.is_local();
628 return EvalResult::Allow;
631 // Issue 38412: private items lack stability markers.
632 if self.skip_stability_check_due_to_privacy(def_id) {
633 return EvalResult::Allow;
637 Some(&Stability { level: attr::Unstable { reason, issue }, feature, .. }) => {
638 if self.stability().active_features.contains(&feature) {
639 return EvalResult::Allow;
642 // When we're compiling the compiler itself we may pull in
643 // crates from crates.io, but those crates may depend on other
644 // crates also pulled in from crates.io. We want to ideally be
645 // able to compile everything without requiring upstream
646 // modifications, so in the case that this looks like a
647 // rustc_private crate (e.g. a compiler crate) and we also have
648 // the `-Z force-unstable-if-unmarked` flag present (we're
649 // compiling a compiler crate), then let this missing feature
651 if feature == "rustc_private" && issue == 27812 {
652 if self.sess.opts.debugging_opts.force_unstable_if_unmarked {
653 return EvalResult::Allow;
657 EvalResult::Deny { feature, reason, issue }
660 // Stable APIs are always ok to call and deprecated APIs are
661 // handled by the lint emitting logic above.
670 /// Checks if an item is stable or error out.
672 /// If the item defined by `def_id` is unstable and the corresponding `#![feature]` does not
673 /// exist, emits an error.
675 /// Additionally, this function will also check if the item is deprecated. If so, and `id` is
676 /// not `None`, a deprecated lint attached to `id` will be emitted.
677 pub fn check_stability(self, def_id: DefId, id: Option<NodeId>, span: Span) {
678 match self.eval_stability(def_id, id, span) {
679 EvalResult::Allow => {}
680 EvalResult::Deny { feature, reason, issue } => {
681 let msg = match reason {
682 Some(r) => format!("use of unstable library feature '{}': {}", feature, r),
683 None => format!("use of unstable library feature '{}'", &feature)
686 let msp: MultiSpan = span.into();
687 let cm = &self.sess.parse_sess.source_map();
688 let span_key = msp.primary_span().and_then(|sp: Span|
690 let file = cm.lookup_char_pos(sp.lo()).file;
691 if file.name.is_macros() {
701 let error_id = (DiagnosticMessageId::StabilityId(issue), span_key, msg.clone());
702 let fresh = self.sess.one_time_diagnostics.borrow_mut().insert(error_id);
704 emit_feature_err(&self.sess.parse_sess, &feature.as_str(), span,
705 GateIssue::Library(Some(issue)), &msg);
708 EvalResult::Unmarked => {
709 span_bug!(span, "encountered unmarked API: {:?}", def_id);
715 impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
716 /// Because stability levels are scoped lexically, we want to walk
717 /// nested items in the context of the outer item, so enable
719 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
720 NestedVisitorMap::OnlyBodies(&self.tcx.hir)
723 fn visit_item(&mut self, item: &'tcx hir::Item) {
725 hir::ItemKind::ExternCrate(_) => {
726 // compiler-generated `extern crate` items have a dummy span.
727 if item.span.is_dummy() { return }
729 let def_id = self.tcx.hir.local_def_id(item.id);
730 let cnum = match self.tcx.extern_mod_stmt_cnum(def_id) {
734 let def_id = DefId { krate: cnum, index: CRATE_DEF_INDEX };
735 self.tcx.check_stability(def_id, Some(item.id), item.span);
738 // For implementations of traits, check the stability of each item
739 // individually as it's possible to have a stable trait with unstable
741 hir::ItemKind::Impl(.., Some(ref t), _, ref impl_item_refs) => {
742 if let Def::Trait(trait_did) = t.path.def {
743 for impl_item_ref in impl_item_refs {
744 let impl_item = self.tcx.hir.impl_item(impl_item_ref.id);
745 let trait_item_def_id = self.tcx.associated_items(trait_did)
746 .find(|item| item.ident.name == impl_item.ident.name)
747 .map(|item| item.def_id);
748 if let Some(def_id) = trait_item_def_id {
749 // Pass `None` to skip deprecation warnings.
750 self.tcx.check_stability(def_id, None, impl_item.span);
756 // There's no good place to insert stability check for non-Copy unions,
757 // so semi-randomly perform it here in stability.rs
758 hir::ItemKind::Union(..) if !self.tcx.features().untagged_unions => {
759 let def_id = self.tcx.hir.local_def_id(item.id);
760 let adt_def = self.tcx.adt_def(def_id);
761 let ty = self.tcx.type_of(def_id);
763 if adt_def.has_dtor(self.tcx) {
764 emit_feature_err(&self.tcx.sess.parse_sess,
765 "untagged_unions", item.span, GateIssue::Language,
766 "unions with `Drop` implementations are unstable");
768 let param_env = self.tcx.param_env(def_id);
769 if !param_env.can_type_implement_copy(self.tcx, ty).is_ok() {
770 emit_feature_err(&self.tcx.sess.parse_sess,
771 "untagged_unions", item.span, GateIssue::Language,
772 "unions with non-`Copy` fields are unstable");
779 intravisit::walk_item(self, item);
782 fn visit_path(&mut self, path: &'tcx hir::Path, id: hir::HirId) {
783 let id = self.tcx.hir.hir_to_node_id(id);
785 Def::Local(..) | Def::Upvar(..) | Def::SelfCtor(..) |
786 Def::PrimTy(..) | Def::SelfTy(..) | Def::Err => {}
787 _ => self.tcx.check_stability(path.def.def_id(), Some(id), path.span)
789 intravisit::walk_path(self, path)
793 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
794 pub fn lookup_deprecation(self, id: DefId) -> Option<Deprecation> {
795 self.lookup_deprecation_entry(id).map(|depr| depr.attr)
799 /// Given the list of enabled features that were not language features (i.e. that
800 /// were expected to be library features), and the list of features used from
801 /// libraries, identify activated features that don't exist and error about them.
802 pub fn check_unused_or_stable_features<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
803 let access_levels = &tcx.privacy_access_levels(LOCAL_CRATE);
805 if tcx.stability().staged_api[&LOCAL_CRATE] {
806 let krate = tcx.hir.krate();
807 let mut missing = MissingStabilityAnnotations {
811 missing.check_missing_stability(ast::CRATE_NODE_ID, krate.span);
812 intravisit::walk_crate(&mut missing, krate);
813 krate.visit_all_item_likes(&mut missing.as_deep_visitor());
816 let declared_lang_features = &tcx.features().declared_lang_features;
817 let mut lang_features = FxHashSet();
818 for &(feature, span, since) in declared_lang_features {
819 if let Some(since) = since {
820 // Warn if the user has enabled an already-stable lang feature.
821 unnecessary_stable_feature_lint(tcx, span, feature, since);
823 if lang_features.contains(&feature) {
824 // Warn if the user enables a lang feature multiple times.
825 duplicate_feature_err(tcx.sess, span, feature);
827 lang_features.insert(feature);
830 let declared_lib_features = &tcx.features().declared_lib_features;
831 let mut remaining_lib_features = FxHashMap();
832 for (feature, span) in declared_lib_features {
833 if remaining_lib_features.contains_key(&feature) {
834 // Warn if the user enables a lib feature multiple times.
835 duplicate_feature_err(tcx.sess, *span, *feature);
837 remaining_lib_features.insert(feature, span.clone());
839 // `stdbuild` has special handling for `libc`, so we need to
840 // recognise the feature when building std.
841 // Likewise, libtest is handled specially, so `test` isn't
842 // available as we'd like it to be.
843 // FIXME: only remove `libc` when `stdbuild` is active.
844 // FIXME: remove special casing for `test`.
845 remaining_lib_features.remove(&Symbol::intern("libc"));
846 remaining_lib_features.remove(&Symbol::intern("test"));
849 |remaining_lib_features: &mut FxHashMap<_, _>, defined_features: &Vec<_>| {
850 for &(feature, since) in defined_features {
851 if let Some(since) = since {
852 if let Some(span) = remaining_lib_features.get(&feature) {
853 // Warn if the user has enabled an already-stable lib feature.
854 unnecessary_stable_feature_lint(tcx, *span, feature, since);
857 remaining_lib_features.remove(&feature);
858 if remaining_lib_features.is_empty() {
864 // We always collect the lib features declared in the current crate, even if there are
865 // no unknown features, because the collection also does feature attribute validation.
866 let local_defined_features = tcx.lib_features().to_vec();
867 if !remaining_lib_features.is_empty() {
868 check_features(&mut remaining_lib_features, &local_defined_features);
870 for &cnum in &*tcx.crates() {
871 if remaining_lib_features.is_empty() {
874 check_features(&mut remaining_lib_features, &tcx.defined_lib_features(cnum));
878 for (feature, span) in remaining_lib_features {
879 struct_span_err!(tcx.sess, span, E0635, "unknown feature `{}`", feature).emit();
882 // FIXME(#44232): the `used_features` table no longer exists, so we
883 // don't lint about unused features. We should reenable this one day!
886 fn unnecessary_stable_feature_lint<'a, 'tcx>(
887 tcx: TyCtxt<'a, 'tcx, 'tcx>,
892 tcx.lint_node(lint::builtin::STABLE_FEATURES,
895 &format!("the feature `{}` has been stable since {} and no longer requires \
896 an attribute to enable", feature, since));
899 fn duplicate_feature_err(sess: &Session, span: Span, feature: Symbol) {
900 struct_span_err!(sess, span, E0636, "the feature `{}` has already been declared", feature)