1 //! A pass that annotates every item and method with its stability level,
2 //! propagating default levels lexically from parent to children ast nodes.
4 pub use self::StabilityLevel::*;
6 use crate::ty::{self, TyCtxt};
8 use rustc_attr::{self as attr, ConstStability, Deprecation, Stability};
9 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
10 use rustc_errors::{Applicability, DiagnosticBuilder};
11 use rustc_feature::GateIssue;
13 use rustc_hir::def::DefKind;
14 use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX};
15 use rustc_hir::{self, HirId};
16 use rustc_middle::ty::print::with_no_trimmed_paths;
17 use rustc_session::lint::builtin::{DEPRECATED, DEPRECATED_IN_FUTURE, SOFT_UNSTABLE};
18 use rustc_session::lint::{BuiltinLintDiagnostics, Lint, LintBuffer};
19 use rustc_session::parse::feature_err_issue;
20 use rustc_session::{DiagnosticMessageId, Session};
21 use rustc_span::symbol::{sym, Symbol};
22 use rustc_span::{MultiSpan, Span};
24 use std::num::NonZeroU32;
26 #[derive(PartialEq, Clone, Copy, Debug)]
27 pub enum StabilityLevel {
32 /// An entry in the `depr_map`.
33 #[derive(Clone, HashStable, Debug)]
34 pub struct DeprecationEntry {
35 /// The metadata of the attribute associated with this entry.
36 pub attr: Deprecation,
37 /// The `DefId` where the attr was originally attached. `None` for non-local
39 origin: Option<HirId>,
42 impl DeprecationEntry {
43 pub fn local(attr: Deprecation, id: HirId) -> DeprecationEntry {
44 DeprecationEntry { attr, origin: Some(id) }
47 pub fn external(attr: Deprecation) -> DeprecationEntry {
48 DeprecationEntry { attr, origin: None }
51 pub fn same_origin(&self, other: &DeprecationEntry) -> bool {
52 match (self.origin, other.origin) {
53 (Some(o1), Some(o2)) => o1 == o2,
59 /// A stability index, giving the stability level for items and methods.
60 #[derive(HashStable, Debug)]
61 pub struct Index<'tcx> {
62 /// This is mostly a cache, except the stabilities of local items
63 /// are filled by the annotator.
64 pub stab_map: FxHashMap<HirId, &'tcx Stability>,
65 pub const_stab_map: FxHashMap<HirId, &'tcx ConstStability>,
66 pub depr_map: FxHashMap<HirId, DeprecationEntry>,
68 /// Maps for each crate whether it is part of the staged API.
69 pub staged_api: FxHashMap<CrateNum, bool>,
71 /// Features enabled for this crate.
72 pub active_features: FxHashSet<Symbol>,
75 impl<'tcx> Index<'tcx> {
76 pub fn local_stability(&self, id: HirId) -> Option<&'tcx Stability> {
77 self.stab_map.get(&id).cloned()
80 pub fn local_const_stability(&self, id: HirId) -> Option<&'tcx ConstStability> {
81 self.const_stab_map.get(&id).cloned()
84 pub fn local_deprecation_entry(&self, id: HirId) -> Option<DeprecationEntry> {
85 self.depr_map.get(&id).cloned()
89 pub fn report_unstable(
92 reason: Option<Symbol>,
93 issue: Option<NonZeroU32>,
96 soft_handler: impl FnOnce(&'static Lint, Span, &str),
98 let msg = match reason {
99 Some(r) => format!("use of unstable library feature '{}': {}", feature, r),
100 None => format!("use of unstable library feature '{}'", &feature),
103 let msp: MultiSpan = span.into();
104 let sm = &sess.parse_sess.source_map();
105 let span_key = msp.primary_span().and_then(|sp: Span| {
107 let file = sm.lookup_char_pos(sp.lo()).file;
108 if file.is_imported() { None } else { Some(span) }
114 let error_id = (DiagnosticMessageId::StabilityId(issue), span_key, msg.clone());
115 let fresh = sess.one_time_diagnostics.borrow_mut().insert(error_id);
118 soft_handler(SOFT_UNSTABLE, span, &msg)
120 feature_err_issue(&sess.parse_sess, feature, span, GateIssue::Library(issue), &msg)
126 /// Checks whether an item marked with `deprecated(since="X")` is currently
127 /// deprecated (i.e., whether X is not greater than the current rustc version).
128 pub fn deprecation_in_effect(is_since_rustc_version: bool, since: Option<&str>) -> bool {
129 fn parse_version(ver: &str) -> Vec<u32> {
130 // We ignore non-integer components of the version (e.g., "nightly").
131 ver.split(|c| c == '.' || c == '-').flat_map(|s| s.parse()).collect()
134 if !is_since_rustc_version {
135 // The `since` field doesn't have semantic purpose in the stable `deprecated`
136 // attribute, only in `rustc_deprecated`.
140 if let Some(since) = since {
145 if let Some(rustc) = option_env!("CFG_RELEASE") {
146 let since: Vec<u32> = parse_version(&since);
147 let rustc: Vec<u32> = parse_version(rustc);
148 // We simply treat invalid `since` attributes as relating to a previous
149 // Rust version, thus always displaying the warning.
150 if since.len() != 3 {
153 return since <= rustc;
157 // Assume deprecation is in effect if "since" field is missing
158 // or if we can't determine the current Rust version.
162 pub fn deprecation_suggestion(
163 diag: &mut DiagnosticBuilder<'_>,
165 suggestion: Option<Symbol>,
168 if let Some(suggestion) = suggestion {
169 diag.span_suggestion(
171 &format!("replace the use of the deprecated {}", kind),
172 suggestion.to_string(),
173 Applicability::MachineApplicable,
178 pub fn deprecation_message(depr: &Deprecation, kind: &str, path: &str) -> (String, &'static Lint) {
179 let since = depr.since.map(Symbol::as_str);
180 let (message, lint) = if deprecation_in_effect(depr.is_since_rustc_version, since.as_deref()) {
181 (format!("use of deprecated {} `{}`", kind, path), DEPRECATED)
184 if since.as_deref() == Some("TBD") {
186 "use of {} `{}` that will be deprecated in a future Rust version",
191 "use of {} `{}` that will be deprecated in future version {}",
197 DEPRECATED_IN_FUTURE,
200 let message = match depr.note {
201 Some(reason) => format!("{}: {}", message, reason),
207 pub fn early_report_deprecation(
208 lint_buffer: &'a mut LintBuffer,
210 suggestion: Option<Symbol>,
215 if span.in_derive_expansion() {
219 let diag = BuiltinLintDiagnostics::DeprecatedMacro(suggestion, span);
220 lint_buffer.buffer_lint_with_diagnostic(lint, node_id, span, message, diag);
223 fn late_report_deprecation(
226 suggestion: Option<Symbol>,
232 if span.in_derive_expansion() {
236 tcx.struct_span_lint_hir(lint, hir_id, span, |lint| {
237 let mut diag = lint.build(message);
238 if let hir::Node::Expr(_) = tcx.hir().get(hir_id) {
239 let kind = tcx.def_kind(def_id).descr(def_id);
240 deprecation_suggestion(&mut diag, kind, suggestion, span);
246 /// Result of `TyCtxt::eval_stability`.
247 pub enum EvalResult {
248 /// We can use the item because it is stable or we provided the
249 /// corresponding feature gate.
251 /// We cannot use the item because it is unstable and we did not provide the
252 /// corresponding feature gate.
253 Deny { feature: Symbol, reason: Option<Symbol>, issue: Option<NonZeroU32>, is_soft: bool },
254 /// The item does not have the `#[stable]` or `#[unstable]` marker assigned.
259 fn skip_stability_check_due_to_privacy(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
260 if tcx.def_kind(def_id) == DefKind::TyParam {
261 // Have no visibility, considered public for the purpose of this check.
264 match tcx.visibility(def_id) {
265 // Must check stability for `pub` items.
266 ty::Visibility::Public => false,
268 // These are not visible outside crate; therefore
269 // stability markers are irrelevant, if even present.
270 ty::Visibility::Restricted(..) | ty::Visibility::Invisible => true,
274 impl<'tcx> TyCtxt<'tcx> {
275 /// Evaluates the stability of an item.
277 /// Returns `EvalResult::Allow` if the item is stable, or unstable but the corresponding
278 /// `#![feature]` has been provided. Returns `EvalResult::Deny` which describes the offending
279 /// unstable feature otherwise.
281 /// If `id` is `Some(_)`, this function will also check if the item at `def_id` has been
282 /// deprecated. If the item is indeed deprecated, we will emit a deprecation lint attached to
284 pub fn eval_stability(self, def_id: DefId, id: Option<HirId>, span: Span) -> EvalResult {
285 // Deprecated attributes apply in-crate and cross-crate.
286 if let Some(id) = id {
287 if let Some(depr_entry) = self.lookup_deprecation_entry(def_id) {
288 let parent_def_id = self.hir().local_def_id(self.hir().get_parent_item(id));
290 .lookup_deprecation_entry(parent_def_id.to_def_id())
291 .map_or(false, |parent_depr| parent_depr.same_origin(&depr_entry));
293 // #[deprecated] doesn't emit a notice if we're not on the
294 // topmost deprecation. For example, if a struct is deprecated,
295 // the use of a field won't be linted.
297 // #[rustc_deprecated] however wants to emit down the whole
299 if !skip || depr_entry.attr.is_since_rustc_version {
300 let path = &with_no_trimmed_paths(|| self.def_path_str(def_id));
301 let kind = self.def_kind(def_id).descr(def_id);
302 let (message, lint) = deprecation_message(&depr_entry.attr, kind, path);
303 late_report_deprecation(
306 depr_entry.attr.suggestion,
317 self.lookup_stability(DefId { index: CRATE_DEF_INDEX, ..def_id }).is_some();
319 return EvalResult::Allow;
322 let stability = self.lookup_stability(def_id);
325 inspecting def_id={:?} span={:?} of stability={:?}",
326 def_id, span, stability
329 // Only the cross-crate scenario matters when checking unstable APIs
330 let cross_crate = !def_id.is_local();
332 return EvalResult::Allow;
335 // Issue #38412: private items lack stability markers.
336 if skip_stability_check_due_to_privacy(self, def_id) {
337 return EvalResult::Allow;
342 level: attr::Unstable { reason, issue, is_soft }, feature, ..
344 if span.allows_unstable(feature) {
345 debug!("stability: skipping span={:?} since it is internal", span);
346 return EvalResult::Allow;
348 if self.stability().active_features.contains(&feature) {
349 return EvalResult::Allow;
352 // When we're compiling the compiler itself we may pull in
353 // crates from crates.io, but those crates may depend on other
354 // crates also pulled in from crates.io. We want to ideally be
355 // able to compile everything without requiring upstream
356 // modifications, so in the case that this looks like a
357 // `rustc_private` crate (e.g., a compiler crate) and we also have
358 // the `-Z force-unstable-if-unmarked` flag present (we're
359 // compiling a compiler crate), then let this missing feature
361 if feature == sym::rustc_private && issue == NonZeroU32::new(27812) {
362 if self.sess.opts.debugging_opts.force_unstable_if_unmarked {
363 return EvalResult::Allow;
367 EvalResult::Deny { feature, reason, issue, is_soft }
370 // Stable APIs are always ok to call and deprecated APIs are
371 // handled by the lint emitting logic above.
374 None => EvalResult::Unmarked,
378 /// Checks if an item is stable or error out.
380 /// If the item defined by `def_id` is unstable and the corresponding `#![feature]` does not
381 /// exist, emits an error.
383 /// This function will also check if the item is deprecated.
384 /// If so, and `id` is not `None`, a deprecated lint attached to `id` will be emitted.
385 pub fn check_stability(self, def_id: DefId, id: Option<HirId>, span: Span) {
386 self.check_optional_stability(def_id, id, span, |span, def_id| {
387 // The API could be uncallable for other reasons, for example when a private module
389 self.sess.delay_span_bug(span, &format!("encountered unmarked API: {:?}", def_id));
393 /// Like `check_stability`, except that we permit items to have custom behaviour for
394 /// missing stability attributes (not necessarily just emit a `bug!`). This is necessary
395 /// for default generic parameters, which only have stability attributes if they were
396 /// added after the type on which they're defined.
397 pub fn check_optional_stability(
402 unmarked: impl FnOnce(Span, DefId),
404 let soft_handler = |lint, span, msg: &_| {
405 self.struct_span_lint_hir(lint, id.unwrap_or(hir::CRATE_HIR_ID), span, |lint| {
406 lint.build(msg).emit()
409 match self.eval_stability(def_id, id, span) {
410 EvalResult::Allow => {}
411 EvalResult::Deny { feature, reason, issue, is_soft } => {
412 report_unstable(self.sess, feature, reason, issue, is_soft, span, soft_handler)
414 EvalResult::Unmarked => unmarked(span, def_id),
418 pub fn lookup_deprecation(self, id: DefId) -> Option<Deprecation> {
419 self.lookup_deprecation_entry(id).map(|depr| depr.attr)