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, LocalDefId, 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<LocalDefId>,
42 impl DeprecationEntry {
43 pub fn local(attr: Deprecation, def_id: LocalDefId) -> DeprecationEntry {
44 DeprecationEntry { attr, origin: Some(def_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<LocalDefId, &'tcx Stability>,
65 pub const_stab_map: FxHashMap<LocalDefId, &'tcx ConstStability>,
66 pub depr_map: FxHashMap<LocalDefId, 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, def_id: LocalDefId) -> Option<&'tcx Stability> {
77 self.stab_map.get(&def_id).copied()
80 pub fn local_const_stability(&self, def_id: LocalDefId) -> Option<&'tcx ConstStability> {
81 self.const_stab_map.get(&def_id).copied()
84 pub fn local_deprecation_entry(&self, def_id: LocalDefId) -> Option<DeprecationEntry> {
85 self.depr_map.get(&def_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>,
229 method_span: Option<Span>,
233 if span.in_derive_expansion() {
236 let method_span = method_span.unwrap_or(span);
237 tcx.struct_span_lint_hir(lint, hir_id, method_span, |lint| {
238 let mut diag = lint.build(message);
239 if let hir::Node::Expr(_) = tcx.hir().get(hir_id) {
240 let kind = tcx.def_kind(def_id).descr(def_id);
241 deprecation_suggestion(&mut diag, kind, suggestion, method_span);
247 /// Result of `TyCtxt::eval_stability`.
248 pub enum EvalResult {
249 /// We can use the item because it is stable or we provided the
250 /// corresponding feature gate.
252 /// We cannot use the item because it is unstable and we did not provide the
253 /// corresponding feature gate.
254 Deny { feature: Symbol, reason: Option<Symbol>, issue: Option<NonZeroU32>, is_soft: bool },
255 /// The item does not have the `#[stable]` or `#[unstable]` marker assigned.
260 fn skip_stability_check_due_to_privacy(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
261 if tcx.def_kind(def_id) == DefKind::TyParam {
262 // Have no visibility, considered public for the purpose of this check.
265 match tcx.visibility(def_id) {
266 // Must check stability for `pub` items.
267 ty::Visibility::Public => false,
269 // These are not visible outside crate; therefore
270 // stability markers are irrelevant, if even present.
271 ty::Visibility::Restricted(..) | ty::Visibility::Invisible => true,
275 impl<'tcx> TyCtxt<'tcx> {
276 /// Evaluates the stability of an item.
278 /// Returns `EvalResult::Allow` if the item is stable, or unstable but the corresponding
279 /// `#![feature]` has been provided. Returns `EvalResult::Deny` which describes the offending
280 /// unstable feature otherwise.
282 /// If `id` is `Some(_)`, this function will also check if the item at `def_id` has been
283 /// deprecated. If the item is indeed deprecated, we will emit a deprecation lint attached to
285 pub fn eval_stability(
290 method_span: Option<Span>,
292 // Deprecated attributes apply in-crate and cross-crate.
293 if let Some(id) = id {
294 if let Some(depr_entry) = self.lookup_deprecation_entry(def_id) {
295 let parent_def_id = self.hir().local_def_id(self.hir().get_parent_item(id));
297 .lookup_deprecation_entry(parent_def_id.to_def_id())
298 .map_or(false, |parent_depr| parent_depr.same_origin(&depr_entry));
300 // #[deprecated] doesn't emit a notice if we're not on the
301 // topmost deprecation. For example, if a struct is deprecated,
302 // the use of a field won't be linted.
304 // #[rustc_deprecated] however wants to emit down the whole
306 if !skip || depr_entry.attr.is_since_rustc_version {
307 let path = &with_no_trimmed_paths(|| self.def_path_str(def_id));
308 let kind = self.def_kind(def_id).descr(def_id);
309 let (message, lint) = deprecation_message(&depr_entry.attr, kind, path);
310 late_report_deprecation(
313 depr_entry.attr.suggestion,
325 self.lookup_stability(DefId { index: CRATE_DEF_INDEX, ..def_id }).is_some();
327 return EvalResult::Allow;
330 let stability = self.lookup_stability(def_id);
333 inspecting def_id={:?} span={:?} of stability={:?}",
334 def_id, span, stability
337 // Only the cross-crate scenario matters when checking unstable APIs
338 let cross_crate = !def_id.is_local();
340 return EvalResult::Allow;
343 // Issue #38412: private items lack stability markers.
344 if skip_stability_check_due_to_privacy(self, def_id) {
345 return EvalResult::Allow;
350 level: attr::Unstable { reason, issue, is_soft }, feature, ..
352 if span.allows_unstable(feature) {
353 debug!("stability: skipping span={:?} since it is internal", span);
354 return EvalResult::Allow;
356 if self.stability().active_features.contains(&feature) {
357 return EvalResult::Allow;
360 // When we're compiling the compiler itself we may pull in
361 // crates from crates.io, but those crates may depend on other
362 // crates also pulled in from crates.io. We want to ideally be
363 // able to compile everything without requiring upstream
364 // modifications, so in the case that this looks like a
365 // `rustc_private` crate (e.g., a compiler crate) and we also have
366 // the `-Z force-unstable-if-unmarked` flag present (we're
367 // compiling a compiler crate), then let this missing feature
369 if feature == sym::rustc_private && issue == NonZeroU32::new(27812) {
370 if self.sess.opts.debugging_opts.force_unstable_if_unmarked {
371 return EvalResult::Allow;
375 EvalResult::Deny { feature, reason, issue, is_soft }
378 // Stable APIs are always ok to call and deprecated APIs are
379 // handled by the lint emitting logic above.
382 None => EvalResult::Unmarked,
386 /// Checks if an item is stable or error out.
388 /// If the item defined by `def_id` is unstable and the corresponding `#![feature]` does not
389 /// exist, emits an error.
391 /// This function will also check if the item is deprecated.
392 /// If so, and `id` is not `None`, a deprecated lint attached to `id` will be emitted.
393 pub fn check_stability(
398 method_span: Option<Span>,
400 self.check_optional_stability(def_id, id, span, method_span, |span, def_id| {
401 // The API could be uncallable for other reasons, for example when a private module
403 self.sess.delay_span_bug(span, &format!("encountered unmarked API: {:?}", def_id));
407 /// Like `check_stability`, except that we permit items to have custom behaviour for
408 /// missing stability attributes (not necessarily just emit a `bug!`). This is necessary
409 /// for default generic parameters, which only have stability attributes if they were
410 /// added after the type on which they're defined.
411 pub fn check_optional_stability(
416 method_span: Option<Span>,
417 unmarked: impl FnOnce(Span, DefId),
419 let soft_handler = |lint, span, msg: &_| {
420 self.struct_span_lint_hir(lint, id.unwrap_or(hir::CRATE_HIR_ID), span, |lint| {
421 lint.build(msg).emit()
424 match self.eval_stability(def_id, id, span, method_span) {
425 EvalResult::Allow => {}
426 EvalResult::Deny { feature, reason, issue, is_soft } => {
427 report_unstable(self.sess, feature, reason, issue, is_soft, span, soft_handler)
429 EvalResult::Unmarked => unmarked(span, def_id),
433 pub fn lookup_deprecation(self, id: DefId) -> Option<Deprecation> {
434 self.lookup_deprecation_entry(id).map(|depr| depr.attr)