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::PublicItems;
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::visit::{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 export_map: &'a PublicItems,
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.export_map.contains(&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 == "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 fn visit_item(&mut self, i: &Item) {
178 let orig_in_trait_impl = self.in_trait_impl;
179 let orig_in_enum = self.in_enum;
180 let mut kind = AnnotationKind::Required;
182 // Inherent impls and foreign modules serve only as containers for other items,
183 // they don't have their own stability. They still can be annotated as unstable
184 // and propagate this unstability to children, but this annotation is completely
185 // optional. They inherit stability from their parents when unannotated.
186 hir::ItemImpl(_, _, _, None, _, _) | hir::ItemForeignMod(..) => {
187 self.in_trait_impl = false;
188 kind = AnnotationKind::Container;
190 hir::ItemImpl(_, _, _, Some(_), _, _) => {
191 self.in_trait_impl = true;
193 hir::ItemStruct(ref sd, _) => {
194 self.in_enum = false;
196 self.annotate(sd.id(), &i.attrs, i.span, AnnotationKind::Required, |_| {})
199 hir::ItemEnum(..) => {
205 self.annotate(i.id, &i.attrs, i.span, kind, |v| {
206 visit::walk_item(v, i)
208 self.in_trait_impl = orig_in_trait_impl;
209 self.in_enum = orig_in_enum;
212 fn visit_trait_item(&mut self, ti: &hir::TraitItem) {
213 self.annotate(ti.id, &ti.attrs, ti.span, AnnotationKind::Required, |v| {
214 visit::walk_trait_item(v, ti);
218 fn visit_impl_item(&mut self, ii: &hir::ImplItem) {
219 let kind = if self.in_trait_impl {
220 AnnotationKind::Prohibited
222 AnnotationKind::Required
224 self.annotate(ii.id, &ii.attrs, ii.span, kind, |v| {
225 visit::walk_impl_item(v, ii);
229 fn visit_variant(&mut self, var: &Variant, g: &'v Generics, item_id: NodeId) {
230 self.annotate(var.node.data.id(), &var.node.attrs, var.span, AnnotationKind::Required, |v| {
231 visit::walk_variant(v, var, g, item_id);
235 fn visit_struct_field(&mut self, s: &StructField) {
236 // FIXME: This is temporary, can't use attributes with tuple variant fields until snapshot
237 let kind = if self.in_enum && s.node.kind.is_unnamed() {
238 AnnotationKind::Prohibited
240 AnnotationKind::Required
242 self.annotate(s.node.id, &s.node.attrs, s.span, kind, |v| {
243 visit::walk_struct_field(v, s);
247 fn visit_foreign_item(&mut self, i: &hir::ForeignItem) {
248 self.annotate(i.id, &i.attrs, i.span, AnnotationKind::Required, |v| {
249 visit::walk_foreign_item(v, i);
253 fn visit_macro_def(&mut self, md: &'v hir::MacroDef) {
254 if md.imported_from.is_none() {
255 self.annotate(md.id, &md.attrs, md.span, AnnotationKind::Required, |_| {});
260 impl<'tcx> Index<'tcx> {
261 /// Construct the stability index for a crate being compiled.
262 pub fn build(&mut self, tcx: &ty::ctxt<'tcx>, krate: &Crate, export_map: &PublicItems) {
263 let mut annotator = Annotator {
267 export_map: export_map,
268 in_trait_impl: false,
271 annotator.annotate(ast::CRATE_NODE_ID, &krate.attrs, krate.span, AnnotationKind::Required,
272 |v| visit::walk_crate(v, krate));
275 pub fn new(krate: &Crate) -> Index {
276 let mut is_staged_api = false;
277 for attr in &krate.attrs {
278 if attr.name() == "staged_api" {
279 if let ast::MetaWord(_) = attr.node.value.node {
280 attr::mark_used(attr);
281 is_staged_api = true;
286 let mut staged_api = FnvHashMap();
287 staged_api.insert(LOCAL_CRATE, is_staged_api);
289 staged_api: staged_api,
295 /// Cross-references the feature names of unstable APIs with enabled
296 /// features and possibly prints errors. Returns a list of all
298 pub fn check_unstable_api_usage(tcx: &ty::ctxt)
299 -> FnvHashMap<InternedString, StabilityLevel> {
300 let ref active_lib_features = tcx.sess.features.borrow().declared_lib_features;
302 // Put the active features into a map for quick lookup
303 let active_features = active_lib_features.iter().map(|&(ref s, _)| s.clone()).collect();
305 let mut checker = Checker {
307 active_features: active_features,
308 used_features: FnvHashMap(),
312 let krate = tcx.map.krate();
313 visit::walk_crate(&mut checker, krate);
315 let used_features = checker.used_features;
316 return used_features;
319 struct Checker<'a, 'tcx: 'a> {
320 tcx: &'a ty::ctxt<'tcx>,
321 active_features: FnvHashSet<InternedString>,
322 used_features: FnvHashMap<InternedString, StabilityLevel>,
323 // Within a block where feature gate checking can be skipped.
327 impl<'a, 'tcx> Checker<'a, 'tcx> {
328 fn check(&mut self, id: DefId, span: Span, stab: &Option<&Stability>) {
329 // Only the cross-crate scenario matters when checking unstable APIs
330 let cross_crate = !id.is_local();
335 // We don't need to check for stability - presumably compiler generated code.
336 if self.in_skip_block > 0 {
341 Some(&Stability { level: attr::Unstable {ref reason, issue}, ref feature, .. }) => {
342 self.used_features.insert(feature.clone(), Unstable);
344 if !self.active_features.contains(feature) {
345 let msg = match *reason {
346 Some(ref r) => format!("use of unstable library feature '{}': {}",
348 None => format!("use of unstable library feature '{}'", &feature)
350 emit_feature_err(&self.tcx.sess.parse_sess.span_diagnostic,
351 &feature, span, GateIssue::Library(Some(issue)), &msg);
354 Some(&Stability { ref level, ref feature, .. }) => {
355 self.used_features.insert(feature.clone(), StabilityLevel::from_attr_level(level));
357 // Stable APIs are always ok to call and deprecated APIs are
358 // handled by a lint.
361 // This is an 'unmarked' API, which should not exist
362 // in the standard library.
363 if self.tcx.sess.features.borrow().unmarked_api {
364 self.tcx.sess.span_warn(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");
369 self.tcx.sess.span_err(span, "use of unmarked library feature");
370 self.tcx.sess.span_note(span, "this is either a bug in the library you are \
371 using or a bug in the compiler - please \
372 report it in both places");
373 self.tcx.sess.span_note(span, "use #![feature(unmarked_api)] in the \
374 crate attributes to override this");
381 impl<'a, 'v, 'tcx> Visitor<'v> for Checker<'a, 'tcx> {
382 fn visit_item(&mut self, item: &hir::Item) {
383 // When compiling with --test we don't enforce stability on the
384 // compiler-generated test module, demarcated with `DUMMY_SP` plus the
386 if item.span == DUMMY_SP && item.name.as_str() == "__test" { return }
388 check_item(self.tcx, item, true,
389 &mut |id, sp, stab| self.check(id, sp, stab));
390 visit::walk_item(self, item);
393 fn visit_expr(&mut self, ex: &hir::Expr) {
394 check_expr(self.tcx, ex,
395 &mut |id, sp, stab| self.check(id, sp, stab));
396 visit::walk_expr(self, ex);
399 fn visit_path(&mut self, path: &hir::Path, id: ast::NodeId) {
400 check_path(self.tcx, path, id,
401 &mut |id, sp, stab| self.check(id, sp, stab));
402 visit::walk_path(self, path)
405 fn visit_path_list_item(&mut self, prefix: &hir::Path, item: &hir::PathListItem) {
406 check_path_list_item(self.tcx, item,
407 &mut |id, sp, stab| self.check(id, sp, stab));
408 visit::walk_path_list_item(self, prefix, item)
411 fn visit_pat(&mut self, pat: &hir::Pat) {
412 check_pat(self.tcx, pat,
413 &mut |id, sp, stab| self.check(id, sp, stab));
414 visit::walk_pat(self, pat)
417 fn visit_block(&mut self, b: &hir::Block) {
418 let old_skip_count = self.in_skip_block;
420 hir::BlockCheckMode::PushUnstableBlock => {
421 self.in_skip_block += 1;
423 hir::BlockCheckMode::PopUnstableBlock => {
424 self.in_skip_block = self.in_skip_block.checked_sub(1).unwrap();
428 visit::walk_block(self, b);
429 self.in_skip_block = old_skip_count;
433 /// Helper for discovering nodes to check for stability
434 pub fn check_item(tcx: &ty::ctxt, item: &hir::Item, warn_about_defns: bool,
435 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
437 hir::ItemExternCrate(_) => {
438 // compiler-generated `extern crate` items have a dummy span.
439 if item.span == DUMMY_SP { return }
441 let cnum = match tcx.sess.cstore.find_extern_mod_stmt_cnum(item.id) {
445 let id = DefId { krate: cnum, index: CRATE_DEF_INDEX };
446 maybe_do_stability_check(tcx, id, item.span, cb);
449 // For implementations of traits, check the stability of each item
450 // individually as it's possible to have a stable trait with unstable
452 hir::ItemImpl(_, _, _, Some(ref t), _, ref impl_items) => {
453 let trait_did = tcx.def_map.borrow().get(&t.ref_id).unwrap().def_id();
454 let trait_items = tcx.trait_items(trait_did);
456 for impl_item in impl_items {
457 let item = trait_items.iter().find(|item| {
458 item.name() == impl_item.name
460 if warn_about_defns {
461 maybe_do_stability_check(tcx, item.def_id(), impl_item.span, cb);
470 /// Helper for discovering nodes to check for stability
471 pub fn check_expr(tcx: &ty::ctxt, e: &hir::Expr,
472 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
474 let id = match e.node {
475 hir::ExprMethodCall(i, _, _) => {
477 let method_call = ty::MethodCall::expr(e.id);
478 tcx.tables.borrow().method_map[&method_call].def_id
480 hir::ExprField(ref base_e, ref field) => {
482 match tcx.expr_ty_adjusted(base_e).sty {
483 ty::TyStruct(def, _) => def.struct_variant().field_named(field.node).did,
484 _ => tcx.sess.span_bug(e.span,
485 "stability::check_expr: named field access on non-struct")
488 hir::ExprTupField(ref base_e, ref field) => {
490 match tcx.expr_ty_adjusted(base_e).sty {
491 ty::TyStruct(def, _) => def.struct_variant().fields[field.node].did,
492 ty::TyTuple(..) => return,
493 _ => tcx.sess.span_bug(e.span,
494 "stability::check_expr: unnamed field access on \
495 something other than a tuple or struct")
498 hir::ExprStruct(_, ref expr_fields, _) => {
499 let type_ = tcx.expr_ty(e);
501 ty::TyStruct(def, _) => {
502 // check the stability of each field that appears
503 // in the construction expression.
504 for field in expr_fields {
505 let did = def.struct_variant()
506 .field_named(field.name.node)
508 maybe_do_stability_check(tcx, did, field.span, cb);
514 // we don't look at stability attributes on
515 // struct-like enums (yet...), but it's definitely not
516 // a bug to have construct one.
517 ty::TyEnum(..) => return,
519 tcx.sess.span_bug(e.span,
520 &format!("stability::check_expr: struct construction \
521 of non-struct, type {:?}",
529 maybe_do_stability_check(tcx, id, span, cb);
532 pub fn check_path(tcx: &ty::ctxt, path: &hir::Path, id: ast::NodeId,
533 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
534 match tcx.def_map.borrow().get(&id).map(|d| d.full_def()) {
535 Some(def::DefPrimTy(..)) => {}
536 Some(def::DefSelfTy(..)) => {}
538 maybe_do_stability_check(tcx, def.def_id(), path.span, cb);
544 pub fn check_path_list_item(tcx: &ty::ctxt, item: &hir::PathListItem,
545 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
546 match tcx.def_map.borrow().get(&item.node.id()).map(|d| d.full_def()) {
547 Some(def::DefPrimTy(..)) => {}
549 maybe_do_stability_check(tcx, def.def_id(), item.span, cb);
555 pub fn check_pat(tcx: &ty::ctxt, pat: &hir::Pat,
556 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
557 debug!("check_pat(pat = {:?})", pat);
558 if is_internal(tcx, pat.span) { return; }
560 let v = match tcx.pat_ty_opt(pat) {
561 Some(&ty::TyS { sty: ty::TyStruct(def, _), .. }) => def.struct_variant(),
562 Some(_) | None => return,
566 // A Variant(..) pattern `hir::PatEnum(_, None)` doesn't have to be recursed into.
567 hir::PatEnum(_, Some(ref pat_fields)) => {
568 for (field, struct_field) in pat_fields.iter().zip(&v.fields) {
569 maybe_do_stability_check(tcx, struct_field.did, field.span, cb)
573 hir::PatStruct(_, ref pat_fields, _) => {
574 for field in pat_fields {
575 let did = v.field_named(field.node.name).did;
576 maybe_do_stability_check(tcx, did, field.span, cb);
579 // everything else is fine.
584 fn maybe_do_stability_check(tcx: &ty::ctxt, id: DefId, span: Span,
585 cb: &mut FnMut(DefId, Span, &Option<&Stability>)) {
586 if !is_staged_api(tcx, id) {
587 debug!("maybe_do_stability_check: \
588 skipping id={:?} since it is not staged_api", id);
591 if is_internal(tcx, span) {
592 debug!("maybe_do_stability_check: \
593 skipping span={:?} since it is internal", span);
596 let ref stability = lookup(tcx, id);
597 debug!("maybe_do_stability_check: \
598 inspecting id={:?} span={:?} of stability={:?}", id, span, stability);
599 cb(id, span, stability);
602 fn is_internal(tcx: &ty::ctxt, span: Span) -> bool {
603 tcx.sess.codemap().span_allows_unstable(span)
606 fn is_staged_api(tcx: &ty::ctxt, id: DefId) -> bool {
607 match tcx.trait_item_of_item(id) {
608 Some(ty::MethodTraitItemId(trait_method_id))
609 if trait_method_id != id => {
610 is_staged_api(tcx, trait_method_id)
613 *tcx.stability.borrow_mut().staged_api.entry(id.krate).or_insert_with(
614 || csearch::is_staged_api(&tcx.sess.cstore, id.krate))
619 /// Lookup the stability for a node, loading external crate
620 /// metadata as necessary.
621 pub fn lookup<'tcx>(tcx: &ty::ctxt<'tcx>, id: DefId) -> Option<&'tcx Stability> {
622 if let Some(st) = tcx.stability.borrow().map.get(&id) {
626 let st = lookup_uncached(tcx, id);
627 tcx.stability.borrow_mut().map.insert(id, st);
631 fn lookup_uncached<'tcx>(tcx: &ty::ctxt<'tcx>, id: DefId) -> Option<&'tcx Stability> {
632 debug!("lookup(id={:?})", id);
634 // is this definition the implementation of a trait method?
635 match tcx.trait_item_of_item(id) {
636 Some(ty::MethodTraitItemId(trait_method_id)) if trait_method_id != id => {
637 debug!("lookup: trait_method_id={:?}", trait_method_id);
638 return lookup(tcx, trait_method_id)
643 let item_stab = if id.is_local() {
644 None // The stability cache is filled partially lazily
646 csearch::get_stability(&tcx.sess.cstore, id).map(|st| tcx.intern_stability(st))
649 item_stab.or_else(|| {
651 if let Some(trait_id) = tcx.trait_id_of_impl(id) {
652 // FIXME (#18969): for the time being, simply use the
653 // stability of the trait to determine the stability of any
654 // unmarked impls for it. See FIXME above for more details.
656 debug!("lookup: trait_id={:?}", trait_id);
657 return lookup(tcx, trait_id);
664 /// Given the list of enabled features that were not language features (i.e. that
665 /// were expected to be library features), and the list of features used from
666 /// libraries, identify activated features that don't exist and error about them.
667 pub fn check_unused_or_stable_features(sess: &Session,
668 lib_features_used: &FnvHashMap<InternedString,
670 let ref declared_lib_features = sess.features.borrow().declared_lib_features;
671 let mut remaining_lib_features: FnvHashMap<InternedString, Span>
672 = declared_lib_features.clone().into_iter().collect();
674 let stable_msg = "this feature is stable. attribute no longer needed";
676 for &span in &sess.features.borrow().declared_stable_lang_features {
677 sess.add_lint(lint::builtin::STABLE_FEATURES,
680 stable_msg.to_string());
683 for (used_lib_feature, level) in lib_features_used {
684 match remaining_lib_features.remove(used_lib_feature) {
686 if *level == Stable {
687 sess.add_lint(lint::builtin::STABLE_FEATURES,
690 stable_msg.to_string());
693 None => ( /* used but undeclared, handled during the previous ast visit */ )
697 for &span in remaining_lib_features.values() {
698 sess.add_lint(lint::builtin::UNUSED_FEATURES,
701 "unused or unknown feature".to_string());