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 metadata::cstore::LOCAL_CRATE;
20 use middle::def_id::{CRATE_DEF_INDEX, DefId};
22 use middle::privacy::AccessLevels;
23 use metadata::csearch;
24 use syntax::parse::token::InternedString;
25 use syntax::codemap::{Span, DUMMY_SP};
27 use syntax::ast::{NodeId, Attribute};
28 use syntax::feature_gate::{GateIssue, emit_feature_err};
29 use syntax::attr::{self, Stability, AttrMetaMethods};
30 use util::nodemap::{DefIdMap, FnvHashSet, FnvHashMap};
33 use rustc_front::hir::{Block, Crate, Item, Generics, StructField, Variant};
34 use rustc_front::intravisit::{self, Visitor};
36 use std::mem::replace;
37 use std::cmp::Ordering;
39 #[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Copy, Debug, Eq, Hash)]
40 pub enum StabilityLevel {
46 pub fn from_attr_level(level: &attr::StabilityLevel) -> Self {
47 if level.is_stable() { Stable } else { Unstable }
53 // Annotation is required if not inherited from unstable parents
55 // Annotation is useless, reject it
57 // Annotation itself is useless, but it can be propagated to children
61 /// A stability index, giving the stability level for items and methods.
62 pub struct Index<'tcx> {
63 /// This is mostly a cache, except the stabilities of local items
64 /// are filled by the annotator.
65 map: DefIdMap<Option<&'tcx Stability>>,
67 /// Maps for each crate whether it is part of the staged API.
68 staged_api: FnvHashMap<ast::CrateNum, bool>
71 // A private tree-walker for producing an Index.
72 struct Annotator<'a, 'tcx: 'a> {
73 tcx: &'a ty::ctxt<'tcx>,
74 index: &'a mut Index<'tcx>,
75 parent: Option<&'tcx Stability>,
76 access_levels: &'a AccessLevels,
81 impl<'a, 'tcx: 'a> Annotator<'a, 'tcx> {
82 // Determine the stability for a node based on its attributes and inherited
83 // stability. The stability is recorded in the index and used as the parent.
84 fn annotate<F>(&mut self, id: NodeId, attrs: &Vec<Attribute>,
85 item_sp: Span, kind: AnnotationKind, visit_children: F)
86 where F: FnOnce(&mut Annotator)
88 if self.index.staged_api[&LOCAL_CRATE] {
89 debug!("annotate(id = {:?}, attrs = {:?})", id, attrs);
90 if let Some(mut stab) = attr::find_stability(self.tcx.sess.diagnostic(),
92 // Error if prohibited, or can't inherit anything from a container
93 if kind == AnnotationKind::Prohibited ||
94 (kind == AnnotationKind::Container &&
95 stab.level.is_stable() &&
96 stab.depr.is_none()) {
97 self.tcx.sess.span_err(item_sp, "This stability annotation is useless");
100 debug!("annotate: found {:?}", stab);
101 // If parent is deprecated and we're not, inherit this by merging
102 // deprecated_since and its reason.
103 if let Some(parent_stab) = self.parent {
104 if parent_stab.depr.is_some() && stab.depr.is_none() {
105 stab.depr = parent_stab.depr.clone()
109 let stab = self.tcx.intern_stability(stab);
111 // Check if deprecated_since < stable_since. If it is,
112 // this is *almost surely* an accident.
113 if let (&Some(attr::Deprecation {since: ref dep_since, ..}),
114 &attr::Stable {since: ref stab_since}) = (&stab.depr, &stab.level) {
115 // Explicit version of iter::order::lt to handle parse errors properly
116 for (dep_v, stab_v) in dep_since.split(".").zip(stab_since.split(".")) {
117 if let (Ok(dep_v), Ok(stab_v)) = (dep_v.parse::<u64>(), stab_v.parse()) {
118 match dep_v.cmp(&stab_v) {
120 self.tcx.sess.span_err(item_sp, "An API can't be stabilized \
121 after it is deprecated");
124 Ordering::Equal => continue,
125 Ordering::Greater => break,
128 // Act like it isn't less because the question is now nonsensical,
129 // and this makes us not do anything else interesting.
130 self.tcx.sess.span_err(item_sp, "Invalid stability or deprecation \
137 let def_id = self.tcx.map.local_def_id(id);
138 self.index.map.insert(def_id, Some(stab));
140 let parent = replace(&mut self.parent, Some(stab));
141 visit_children(self);
142 self.parent = parent;
144 debug!("annotate: not found, parent = {:?}", self.parent);
145 let mut is_error = kind == AnnotationKind::Required &&
146 self.access_levels.is_reachable(id) &&
147 !self.tcx.sess.opts.test;
148 if let Some(stab) = self.parent {
149 if stab.level.is_unstable() {
150 let def_id = self.tcx.map.local_def_id(id);
151 self.index.map.insert(def_id, Some(stab));
156 self.tcx.sess.span_err(item_sp, "This node does not have \
157 a stability attribute");
159 visit_children(self);
162 // Emit errors for non-staged-api crates.
164 let tag = attr.name();
165 if tag == "unstable" || tag == "stable" || tag == "rustc_deprecated" {
166 attr::mark_used(attr);
167 self.tcx.sess.span_err(attr.span(), "stability attributes may not be used \
168 outside of the standard library");
171 visit_children(self);
176 impl<'a, 'tcx, 'v> Visitor<'v> for Annotator<'a, 'tcx> {
177 /// Because stability levels are scoped lexically, we want to walk
178 /// nested items in the context of the outer item, so enable
180 fn visit_nested_item(&mut self, item: hir::ItemId) {
181 self.visit_item(self.tcx.map.expect_item(item.id))
184 fn visit_item(&mut self, i: &Item) {
185 let orig_in_trait_impl = self.in_trait_impl;
186 let orig_in_enum = self.in_enum;
187 let mut kind = AnnotationKind::Required;
189 // Inherent impls and foreign modules serve only as containers for other items,
190 // they don't have their own stability. They still can be annotated as unstable
191 // and propagate this unstability to children, but this annotation is completely
192 // optional. They inherit stability from their parents when unannotated.
193 hir::ItemImpl(_, _, _, None, _, _) | hir::ItemForeignMod(..) => {
194 self.in_trait_impl = false;
195 kind = AnnotationKind::Container;
197 hir::ItemImpl(_, _, _, Some(_), _, _) => {
198 self.in_trait_impl = true;
200 hir::ItemStruct(ref sd, _) => {
201 self.in_enum = false;
203 self.annotate(sd.id(), &i.attrs, i.span, AnnotationKind::Required, |_| {})
206 hir::ItemEnum(..) => {
212 self.annotate(i.id, &i.attrs, i.span, kind, |v| {
213 intravisit::walk_item(v, i)
215 self.in_trait_impl = orig_in_trait_impl;
216 self.in_enum = orig_in_enum;
219 fn visit_trait_item(&mut self, ti: &hir::TraitItem) {
220 self.annotate(ti.id, &ti.attrs, ti.span, AnnotationKind::Required, |v| {
221 intravisit::walk_trait_item(v, ti);
225 fn visit_impl_item(&mut self, ii: &hir::ImplItem) {
226 let kind = if self.in_trait_impl {
227 AnnotationKind::Prohibited
229 AnnotationKind::Required
231 self.annotate(ii.id, &ii.attrs, ii.span, kind, |v| {
232 intravisit::walk_impl_item(v, ii);
236 fn visit_variant(&mut self, var: &Variant, g: &'v Generics, item_id: NodeId) {
237 self.annotate(var.node.data.id(), &var.node.attrs, var.span, AnnotationKind::Required, |v| {
238 intravisit::walk_variant(v, var, g, item_id);
242 fn visit_struct_field(&mut self, s: &StructField) {
243 // FIXME: This is temporary, can't use attributes with tuple variant fields until snapshot
244 let kind = if self.in_enum && s.node.kind.is_unnamed() {
245 AnnotationKind::Prohibited
247 AnnotationKind::Required
249 self.annotate(s.node.id, &s.node.attrs, s.span, kind, |v| {
250 intravisit::walk_struct_field(v, s);
254 fn visit_foreign_item(&mut self, i: &hir::ForeignItem) {
255 self.annotate(i.id, &i.attrs, i.span, AnnotationKind::Required, |v| {
256 intravisit::walk_foreign_item(v, i);
260 fn visit_macro_def(&mut self, md: &'v hir::MacroDef) {
261 if md.imported_from.is_none() {
262 self.annotate(md.id, &md.attrs, md.span, AnnotationKind::Required, |_| {});
267 impl<'tcx> Index<'tcx> {
268 /// Construct the stability index for a crate being compiled.
269 pub fn build(&mut self, tcx: &ty::ctxt<'tcx>, krate: &Crate, access_levels: &AccessLevels) {
270 let mut annotator = Annotator {
274 access_levels: access_levels,
275 in_trait_impl: false,
278 annotator.annotate(ast::CRATE_NODE_ID, &krate.attrs, krate.span, AnnotationKind::Required,
279 |v| intravisit::walk_crate(v, krate));
282 pub fn new(sess: &Session) -> Index<'tcx> {
283 let mut staged_api = FnvHashMap();
284 staged_api.insert(LOCAL_CRATE, sess.features.borrow().staged_api);
286 staged_api: staged_api,
292 /// Cross-references the feature names of unstable APIs with enabled
293 /// features and possibly prints errors. Returns a list of all
295 pub fn check_unstable_api_usage(tcx: &ty::ctxt)
296 -> FnvHashMap<InternedString, StabilityLevel> {
297 let ref active_lib_features = tcx.sess.features.borrow().declared_lib_features;
299 // Put the active features into a map for quick lookup
300 let active_features = active_lib_features.iter().map(|&(ref s, _)| s.clone()).collect();
302 let mut checker = Checker {
304 active_features: active_features,
305 used_features: FnvHashMap(),
308 intravisit::walk_crate(&mut checker, tcx.map.krate());
310 let used_features = checker.used_features;
311 return used_features;
314 struct Checker<'a, 'tcx: 'a> {
315 tcx: &'a ty::ctxt<'tcx>,
316 active_features: FnvHashSet<InternedString>,
317 used_features: FnvHashMap<InternedString, StabilityLevel>,
318 // Within a block where feature gate checking can be skipped.
322 impl<'a, 'tcx> Checker<'a, 'tcx> {
323 fn check(&mut self, id: DefId, span: Span, stab: &Option<&Stability>) {
324 // Only the cross-crate scenario matters when checking unstable APIs
325 let cross_crate = !id.is_local();
330 // We don't need to check for stability - presumably compiler generated code.
331 if self.in_skip_block > 0 {
336 Some(&Stability { level: attr::Unstable {ref reason, issue}, ref feature, .. }) => {
337 self.used_features.insert(feature.clone(), Unstable);
339 if !self.active_features.contains(feature) {
340 let msg = match *reason {
341 Some(ref r) => format!("use of unstable library feature '{}': {}",
343 None => format!("use of unstable library feature '{}'", &feature)
345 emit_feature_err(&self.tcx.sess.parse_sess.span_diagnostic,
346 &feature, span, GateIssue::Library(Some(issue)), &msg);
349 Some(&Stability { ref level, ref feature, .. }) => {
350 self.used_features.insert(feature.clone(), StabilityLevel::from_attr_level(level));
352 // Stable APIs are always ok to call and deprecated APIs are
353 // handled by a lint.
356 // This is an 'unmarked' API, which should not exist
357 // in the standard library.
358 if self.tcx.sess.features.borrow().unmarked_api {
359 self.tcx.sess.span_warn(span, "use of unmarked library feature");
360 self.tcx.sess.span_note(span, "this is either a bug in the library you are \
361 using or a bug in the compiler - please \
362 report it in both places");
364 self.tcx.sess.span_err(span, "use of unmarked library feature");
365 self.tcx.sess.span_note(span, "this is either a bug in the library you are \
366 using or a bug in the compiler - please \
367 report it in both places");
368 self.tcx.sess.span_note(span, "use #![feature(unmarked_api)] in the \
369 crate attributes to override this");
376 impl<'a, 'v, 'tcx> Visitor<'v> for Checker<'a, 'tcx> {
377 /// Because stability levels are scoped lexically, we want to walk
378 /// nested items in the context of the outer item, so enable
380 fn visit_nested_item(&mut self, item: hir::ItemId) {
381 self.visit_item(self.tcx.map.expect_item(item.id))
384 fn visit_item(&mut self, item: &hir::Item) {
385 // When compiling with --test we don't enforce stability on the
386 // compiler-generated test module, demarcated with `DUMMY_SP` plus the
388 if item.span == DUMMY_SP && item.name.as_str() == "__test" { return }
390 check_item(self.tcx, item, true,
391 &mut |id, sp, stab| self.check(id, sp, stab));
392 intravisit::walk_item(self, item);
395 fn visit_expr(&mut self, ex: &hir::Expr) {
396 check_expr(self.tcx, ex,
397 &mut |id, sp, stab| self.check(id, sp, stab));
398 intravisit::walk_expr(self, ex);
401 fn visit_path(&mut self, path: &hir::Path, id: ast::NodeId) {
402 check_path(self.tcx, path, id,
403 &mut |id, sp, stab| self.check(id, sp, stab));
404 intravisit::walk_path(self, path)
407 fn visit_path_list_item(&mut self, prefix: &hir::Path, item: &hir::PathListItem) {
408 check_path_list_item(self.tcx, item,
409 &mut |id, sp, stab| self.check(id, sp, stab));
410 intravisit::walk_path_list_item(self, prefix, item)
413 fn visit_pat(&mut self, pat: &hir::Pat) {
414 check_pat(self.tcx, pat,
415 &mut |id, sp, stab| self.check(id, sp, stab));
416 intravisit::walk_pat(self, pat)
419 fn visit_block(&mut self, b: &hir::Block) {
420 let old_skip_count = self.in_skip_block;
422 hir::BlockCheckMode::PushUnstableBlock => {
423 self.in_skip_block += 1;
425 hir::BlockCheckMode::PopUnstableBlock => {
426 self.in_skip_block = self.in_skip_block.checked_sub(1).unwrap();
430 intravisit::walk_block(self, b);
431 self.in_skip_block = old_skip_count;
435 /// Helper for discovering nodes to check for stability
436 pub fn check_item(tcx: &ty::ctxt, item: &hir::Item, warn_about_defns: bool,
437 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
439 hir::ItemExternCrate(_) => {
440 // compiler-generated `extern crate` items have a dummy span.
441 if item.span == DUMMY_SP { return }
443 let cnum = match tcx.sess.cstore.find_extern_mod_stmt_cnum(item.id) {
447 let id = DefId { krate: cnum, index: CRATE_DEF_INDEX };
448 maybe_do_stability_check(tcx, id, item.span, cb);
451 // For implementations of traits, check the stability of each item
452 // individually as it's possible to have a stable trait with unstable
454 hir::ItemImpl(_, _, _, Some(ref t), _, ref impl_items) => {
455 let trait_did = tcx.def_map.borrow().get(&t.ref_id).unwrap().def_id();
456 let trait_items = tcx.trait_items(trait_did);
458 for impl_item in impl_items {
459 let item = trait_items.iter().find(|item| {
460 item.name() == impl_item.name
462 if warn_about_defns {
463 maybe_do_stability_check(tcx, item.def_id(), impl_item.span, cb);
472 /// Helper for discovering nodes to check for stability
473 pub fn check_expr(tcx: &ty::ctxt, e: &hir::Expr,
474 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
476 let id = match e.node {
477 hir::ExprMethodCall(i, _, _) => {
479 let method_call = ty::MethodCall::expr(e.id);
480 tcx.tables.borrow().method_map[&method_call].def_id
482 hir::ExprField(ref base_e, ref field) => {
484 match tcx.expr_ty_adjusted(base_e).sty {
485 ty::TyStruct(def, _) => def.struct_variant().field_named(field.node).did,
486 _ => tcx.sess.span_bug(e.span,
487 "stability::check_expr: named field access on non-struct")
490 hir::ExprTupField(ref base_e, ref field) => {
492 match tcx.expr_ty_adjusted(base_e).sty {
493 ty::TyStruct(def, _) => def.struct_variant().fields[field.node].did,
494 ty::TyTuple(..) => return,
495 _ => tcx.sess.span_bug(e.span,
496 "stability::check_expr: unnamed field access on \
497 something other than a tuple or struct")
500 hir::ExprStruct(_, ref expr_fields, _) => {
501 let type_ = tcx.expr_ty(e);
503 ty::TyStruct(def, _) => {
504 // check the stability of each field that appears
505 // in the construction expression.
506 for field in expr_fields {
507 let did = def.struct_variant()
508 .field_named(field.name.node)
510 maybe_do_stability_check(tcx, did, field.span, cb);
516 // we don't look at stability attributes on
517 // struct-like enums (yet...), but it's definitely not
518 // a bug to have construct one.
519 ty::TyEnum(..) => return,
521 tcx.sess.span_bug(e.span,
522 &format!("stability::check_expr: struct construction \
523 of non-struct, type {:?}",
531 maybe_do_stability_check(tcx, id, span, cb);
534 pub fn check_path(tcx: &ty::ctxt, path: &hir::Path, id: ast::NodeId,
535 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
536 match tcx.def_map.borrow().get(&id).map(|d| d.full_def()) {
537 Some(def::DefPrimTy(..)) => {}
538 Some(def::DefSelfTy(..)) => {}
540 maybe_do_stability_check(tcx, def.def_id(), path.span, cb);
546 pub fn check_path_list_item(tcx: &ty::ctxt, item: &hir::PathListItem,
547 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
548 match tcx.def_map.borrow().get(&item.node.id()).map(|d| d.full_def()) {
549 Some(def::DefPrimTy(..)) => {}
551 maybe_do_stability_check(tcx, def.def_id(), item.span, cb);
557 pub fn check_pat(tcx: &ty::ctxt, pat: &hir::Pat,
558 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
559 debug!("check_pat(pat = {:?})", pat);
560 if is_internal(tcx, pat.span) { return; }
562 let v = match tcx.pat_ty_opt(pat) {
563 Some(&ty::TyS { sty: ty::TyStruct(def, _), .. }) => def.struct_variant(),
564 Some(_) | None => return,
568 // A Variant(..) pattern `hir::PatEnum(_, None)` doesn't have to be recursed into.
569 hir::PatEnum(_, Some(ref pat_fields)) => {
570 for (field, struct_field) in pat_fields.iter().zip(&v.fields) {
571 maybe_do_stability_check(tcx, struct_field.did, field.span, cb)
575 hir::PatStruct(_, ref pat_fields, _) => {
576 for field in pat_fields {
577 let did = v.field_named(field.node.name).did;
578 maybe_do_stability_check(tcx, did, field.span, cb);
581 // everything else is fine.
586 fn maybe_do_stability_check(tcx: &ty::ctxt, id: DefId, span: Span,
587 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
588 if !is_staged_api(tcx, id) {
589 debug!("maybe_do_stability_check: \
590 skipping id={:?} since it is not staged_api", id);
593 if is_internal(tcx, span) {
594 debug!("maybe_do_stability_check: \
595 skipping span={:?} since it is internal", span);
598 let ref stability = lookup(tcx, id);
599 debug!("maybe_do_stability_check: \
600 inspecting id={:?} span={:?} of stability={:?}", id, span, stability);
601 cb(id, span, stability);
604 fn is_internal(tcx: &ty::ctxt, span: Span) -> bool {
605 tcx.sess.codemap().span_allows_unstable(span)
608 fn is_staged_api(tcx: &ty::ctxt, id: DefId) -> bool {
609 match tcx.trait_item_of_item(id) {
610 Some(ty::MethodTraitItemId(trait_method_id))
611 if trait_method_id != id => {
612 is_staged_api(tcx, trait_method_id)
615 *tcx.stability.borrow_mut().staged_api.entry(id.krate).or_insert_with(
616 || csearch::is_staged_api(&tcx.sess.cstore, id.krate))
621 /// Lookup the stability for a node, loading external crate
622 /// metadata as necessary.
623 pub fn lookup<'tcx>(tcx: &ty::ctxt<'tcx>, id: DefId) -> Option<&'tcx Stability> {
624 if let Some(st) = tcx.stability.borrow().map.get(&id) {
628 let st = lookup_uncached(tcx, id);
629 tcx.stability.borrow_mut().map.insert(id, st);
633 fn lookup_uncached<'tcx>(tcx: &ty::ctxt<'tcx>, id: DefId) -> Option<&'tcx Stability> {
634 debug!("lookup(id={:?})", id);
636 // is this definition the implementation of a trait method?
637 match tcx.trait_item_of_item(id) {
638 Some(ty::MethodTraitItemId(trait_method_id)) if trait_method_id != id => {
639 debug!("lookup: trait_method_id={:?}", trait_method_id);
640 return lookup(tcx, trait_method_id)
645 let item_stab = if id.is_local() {
646 None // The stability cache is filled partially lazily
648 csearch::get_stability(&tcx.sess.cstore, id).map(|st| tcx.intern_stability(st))
651 item_stab.or_else(|| {
653 if let Some(trait_id) = tcx.trait_id_of_impl(id) {
654 // FIXME (#18969): for the time being, simply use the
655 // stability of the trait to determine the stability of any
656 // unmarked impls for it. See FIXME above for more details.
658 debug!("lookup: trait_id={:?}", trait_id);
659 return lookup(tcx, trait_id);
666 /// Given the list of enabled features that were not language features (i.e. that
667 /// were expected to be library features), and the list of features used from
668 /// libraries, identify activated features that don't exist and error about them.
669 pub fn check_unused_or_stable_features(sess: &Session,
670 lib_features_used: &FnvHashMap<InternedString,
672 let ref declared_lib_features = sess.features.borrow().declared_lib_features;
673 let mut remaining_lib_features: FnvHashMap<InternedString, Span>
674 = declared_lib_features.clone().into_iter().collect();
676 let stable_msg = "this feature is stable. attribute no longer needed";
678 for &span in &sess.features.borrow().declared_stable_lang_features {
679 sess.add_lint(lint::builtin::STABLE_FEATURES,
682 stable_msg.to_string());
685 for (used_lib_feature, level) in lib_features_used {
686 match remaining_lib_features.remove(used_lib_feature) {
688 if *level == Stable {
689 sess.add_lint(lint::builtin::STABLE_FEATURES,
692 stable_msg.to_string());
695 None => ( /* used but undeclared, handled during the previous ast visit */ )
699 for &span in remaining_lib_features.values() {
700 sess.add_lint(lint::builtin::UNUSED_FEATURES,
703 "unused or unknown feature".to_string());