1 // Copyright 2012-2014 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 //! Implementation of lint checking.
13 //! The lint checking is mostly consolidated into one pass which runs just
14 //! before translation to LLVM bytecode. Throughout compilation, lint warnings
15 //! can be added via the `add_lint` method on the Session structure. This
16 //! requires a span and an id of the node that the lint is being added to. The
17 //! lint isn't actually emitted at that time because it is unknown what the
18 //! actual lint level at that location is.
20 //! To actually emit lint warnings/errors, a separate pass is used just before
21 //! translation. A context keeps track of the current state of all lint levels.
22 //! Upon entering a node of the ast which can modify the lint settings, the
23 //! previous lint state is pushed onto a stack and the ast is then recursed
24 //! upon. As the ast is traversed, this keeps track of the current lint level
25 //! for all lint attributes.
26 use self::TargetLint::*;
28 use middle::privacy::ExportedItems;
29 use middle::ty::{self, Ty};
30 use session::{early_error, Session};
31 use session::config::UnstableFeatures;
32 use lint::{Level, LevelSource, Lint, LintId, LintArray, LintPass, LintPassObject};
33 use lint::{Default, CommandLine, Node, Allow, Warn, Deny, Forbid, ReleaseChannel};
35 use util::nodemap::FnvHashMap;
37 use std::cell::RefCell;
39 use syntax::ast_util::IdVisitingOperation;
40 use syntax::attr::AttrMetaMethods;
42 use syntax::codemap::Span;
43 use syntax::visit::{Visitor, FnKind};
44 use syntax::parse::token::InternedString;
45 use syntax::{ast, ast_util, visit};
47 /// Information about the registered lints.
49 /// This is basically the subset of `Context` that we can
50 /// build early in the compile pipeline.
51 pub struct LintStore {
52 /// Registered lints. The bool is true if the lint was
53 /// added by a plugin.
54 lints: Vec<(&'static Lint, bool)>,
56 /// Trait objects for each lint pass.
57 /// This is only `None` while iterating over the objects. See the definition
59 passes: Option<Vec<LintPassObject>>,
61 /// Lints indexed by name.
62 by_name: FnvHashMap<String, TargetLint>,
64 /// Current levels of each lint, and where they were set.
65 levels: FnvHashMap<LintId, LevelSource>,
67 /// Map of registered lint groups to what lints they expand to. The bool
68 /// is true if the lint group was added by a plugin.
69 lint_groups: FnvHashMap<&'static str, (Vec<LintId>, bool)>,
72 /// The targed of the `by_name` map, which accounts for renaming/deprecation.
74 /// A direct lint target
77 /// Temporary renaming, used for easing migration pain; see #16545
78 Renamed(String, LintId),
82 fn get_level_source(&self, lint: LintId) -> LevelSource {
83 match self.levels.get(&lint) {
85 None => (Allow, Default),
89 fn set_level(&mut self, lint: LintId, lvlsrc: LevelSource) {
90 if lvlsrc.0 == Allow {
91 self.levels.remove(&lint);
93 self.levels.insert(lint, lvlsrc);
97 pub fn new() -> LintStore {
100 passes: Some(vec!()),
101 by_name: FnvHashMap(),
102 levels: FnvHashMap(),
103 lint_groups: FnvHashMap(),
107 pub fn get_lints<'t>(&'t self) -> &'t [(&'static Lint, bool)] {
111 pub fn get_lint_groups<'t>(&'t self) -> Vec<(&'static str, Vec<LintId>, bool)> {
112 self.lint_groups.iter().map(|(k, v)| (*k,
117 pub fn register_pass(&mut self, sess: Option<&Session>,
118 from_plugin: bool, pass: LintPassObject) {
119 for &lint in pass.get_lints().iter() {
120 self.lints.push((*lint, from_plugin));
122 let id = LintId::of(*lint);
123 if self.by_name.insert(lint.name_lower(), Id(id)).is_some() {
124 let msg = format!("duplicate specification of lint {}", lint.name_lower());
125 match (sess, from_plugin) {
126 // We load builtin lints first, so a duplicate is a compiler bug.
127 // Use early_error when handling -W help with no crate.
128 (None, _) => early_error(&msg[]),
129 (Some(sess), false) => sess.bug(&msg[]),
131 // A duplicate name from a plugin is a user error.
132 (Some(sess), true) => sess.err(&msg[]),
136 if lint.default_level != Allow {
137 self.levels.insert(id, (lint.default_level, Default));
140 self.passes.as_mut().unwrap().push(pass);
143 pub fn register_group(&mut self, sess: Option<&Session>,
144 from_plugin: bool, name: &'static str,
146 let new = self.lint_groups.insert(name, (to, from_plugin)).is_none();
149 let msg = format!("duplicate specification of lint group {}", name);
150 match (sess, from_plugin) {
151 // We load builtin lints first, so a duplicate is a compiler bug.
152 // Use early_error when handling -W help with no crate.
153 (None, _) => early_error(&msg[]),
154 (Some(sess), false) => sess.bug(&msg[]),
156 // A duplicate name from a plugin is a user error.
157 (Some(sess), true) => sess.err(&msg[]),
162 fn register_renamed(&mut self, old_name: &str, new_name: &str) {
163 let target = match self.by_name.get(new_name) {
164 Some(&Id(lint_id)) => lint_id.clone(),
165 _ => panic!("invalid lint renaming of {} to {}", old_name, new_name)
167 self.by_name.insert(old_name.to_string(), Renamed(new_name.to_string(), target));
170 pub fn register_builtin(&mut self, sess: Option<&Session>) {
171 macro_rules! add_builtin {
172 ($sess:ident, $($name:ident),*,) => (
174 self.register_pass($sess, false, box builtin::$name as LintPassObject);
179 macro_rules! add_builtin_with_new {
180 ($sess:ident, $($name:ident),*,) => (
182 self.register_pass($sess, false, box builtin::$name::new() as LintPassObject);
187 macro_rules! add_lint_group {
188 ($sess:ident, $name:expr, $($lint:ident),*) => (
189 self.register_group($sess, false, $name, vec![$(LintId::of(builtin::$lint)),*]);
207 NonShorthandFieldPatterns,
212 MissingCopyImplementations,
216 add_builtin_with_new!(sess,
223 add_lint_group!(sess, "bad_style",
224 NON_CAMEL_CASE_TYPES, NON_SNAKE_CASE, NON_UPPER_CASE_GLOBALS);
226 add_lint_group!(sess, "unused",
227 UNUSED_IMPORTS, UNUSED_VARIABLES, UNUSED_ASSIGNMENTS, DEAD_CODE,
228 UNUSED_MUT, UNREACHABLE_CODE, UNUSED_MUST_USE,
229 UNUSED_UNSAFE, PATH_STATEMENTS);
231 // We have one lint pass defined in this module.
232 self.register_pass(sess, false, box GatherNodeLevels as LintPassObject);
234 // Insert temporary renamings for a one-time deprecation (#16545)
235 self.register_renamed("unnecessary_typecast", "unused_typecasts");
236 self.register_renamed("unsigned_negate", "unsigned_negation");
237 self.register_renamed("type_limits", "unused_comparisons");
238 self.register_renamed("type_overflow", "overflowing_literals");
239 self.register_renamed("ctypes", "improper_ctypes");
240 self.register_renamed("owned_heap_memory", "box_pointers");
241 self.register_renamed("unused_attribute", "unused_attributes");
242 self.register_renamed("path_statement", "path_statements");
243 self.register_renamed("unused_result", "unused_results");
244 self.register_renamed("non_uppercase_statics", "non_upper_case_globals");
245 self.register_renamed("unnecessary_parens", "unused_parens");
246 self.register_renamed("unnecessary_import_braces", "unused_import_braces");
247 self.register_renamed("unsafe_block", "unsafe_blocks");
248 self.register_renamed("unnecessary_allocation", "unused_allocation");
249 self.register_renamed("missing_doc", "missing_docs");
250 self.register_renamed("unused_extern_crate", "unused_extern_crates");
251 self.register_renamed("unnecessary_qualification", "unused_qualifications");
252 self.register_renamed("unrecognized_lint", "unknown_lints");
253 self.register_renamed("unused_variable", "unused_variables");
254 self.register_renamed("dead_assignment", "unused_assignments");
255 self.register_renamed("unknown_crate_type", "unknown_crate_types");
256 self.register_renamed("variant_size_difference", "variant_size_differences");
257 self.register_renamed("transmute_fat_ptr", "fat_ptr_transmutes");
258 self.register_renamed("raw_pointer_deriving", "raw_pointer_derive");
262 #[allow(unused_variables)]
263 fn find_lint(&self, lint_name: &str, sess: &Session, span: Option<Span>)
266 match self.by_name.get(lint_name) {
267 Some(&Id(lint_id)) => Some(lint_id),
268 Some(&Renamed(ref new_name, lint_id)) => {
269 let warning = format!("lint {} has been renamed to {}",
270 lint_name, new_name);
272 Some(span) => sess.span_warn(span, &warning[]),
273 None => sess.warn(&warning[]),
281 pub fn process_command_line(&mut self, sess: &Session) {
282 for &(ref lint_name, level) in sess.opts.lint_opts.iter() {
283 match self.find_lint(&lint_name[], sess, None) {
284 Some(lint_id) => self.set_level(lint_id, (level, CommandLine)),
286 match self.lint_groups.iter().map(|(&x, pair)| (x, pair.0.clone()))
287 .collect::<FnvHashMap<&'static str,
292 .map(|lint_id: &LintId|
293 self.set_level(*lint_id, (level, CommandLine)))
294 .collect::<Vec<()>>();
296 None => sess.err(&format!("unknown {} flag: {}",
297 level.as_str(), lint_name)[]),
304 fn maybe_stage_features(&mut self, sess: &Session) {
305 let lvl = match sess.opts.unstable_features {
306 UnstableFeatures::Default => return,
307 UnstableFeatures::Disallow => Warn,
308 UnstableFeatures::Cheat => Allow
310 match self.by_name.get("unstable_features") {
311 Some(&Id(lint_id)) => if self.get_level_source(lint_id).0 != Forbid {
312 self.set_level(lint_id, (lvl, ReleaseChannel))
314 Some(&Renamed(_, lint_id)) => if self.get_level_source(lint_id).0 != Forbid {
315 self.set_level(lint_id, (lvl, ReleaseChannel))
317 None => unreachable!()
319 match self.by_name.get("unstable") {
320 Some(&Id(lint_id)) => if self.get_level_source(lint_id).0 != Forbid {
321 self.set_level(lint_id, (lvl, ReleaseChannel))
323 Some(&Renamed(_, lint_id)) => if self.get_level_source(lint_id).0 != Forbid {
324 self.set_level(lint_id, (lvl, ReleaseChannel))
326 None => unreachable!()
331 /// Context for lint checking.
332 pub struct Context<'a, 'tcx: 'a> {
333 /// Type context we're checking in.
334 pub tcx: &'a ty::ctxt<'tcx>,
336 /// The crate being checked.
337 pub krate: &'a ast::Crate,
339 /// Items exported from the crate being checked.
340 pub exported_items: &'a ExportedItems,
342 /// The store of registered lints.
345 /// When recursing into an attributed node of the ast which modifies lint
346 /// levels, this stack keeps track of the previous lint levels of whatever
348 level_stack: Vec<(LintId, LevelSource)>,
350 /// Level of lints for certain NodeIds, stored here because the body of
351 /// the lint needs to run in trans.
352 node_levels: RefCell<FnvHashMap<(ast::NodeId, LintId), LevelSource>>,
355 /// Convenience macro for calling a `LintPass` method on every pass in the context.
356 macro_rules! run_lints { ($cx:expr, $f:ident, $($args:expr),*) => ({
357 // Move the vector of passes out of `$cx` so that we can
358 // iterate over it mutably while passing `$cx` to the methods.
359 let mut passes = $cx.lints.passes.take().unwrap();
360 for obj in passes.iter_mut() {
361 obj.$f($cx, $($args),*);
363 $cx.lints.passes = Some(passes);
366 /// Parse the lint attributes into a vector, with `Err`s for malformed lint
367 /// attributes. Writing this as an iterator is an enormous mess.
368 pub fn gather_attrs(attrs: &[ast::Attribute])
369 -> Vec<Result<(InternedString, Level, Span), Span>> {
370 let mut out = vec!();
371 for attr in attrs.iter() {
372 let level = match Level::from_str(attr.name().get()) {
377 attr::mark_used(attr);
379 let meta = &attr.node.value;
380 let metas = match meta.node {
381 ast::MetaList(_, ref metas) => metas,
383 out.push(Err(meta.span));
388 for meta in metas.iter() {
389 out.push(match meta.node {
390 ast::MetaWord(ref lint_name) => Ok((lint_name.clone(), level, meta.span)),
398 /// Emit a lint as a warning or an error (or not at all)
399 /// according to `level`.
401 /// This lives outside of `Context` so it can be used by checks
402 /// in trans that run after the main lint pass is finished. Most
403 /// lints elsewhere in the compiler should call
404 /// `Session::add_lint()` instead.
405 pub fn raw_emit_lint(sess: &Session, lint: &'static Lint,
406 lvlsrc: LevelSource, span: Option<Span>, msg: &str) {
407 let (mut level, source) = lvlsrc;
408 if level == Allow { return }
410 let name = lint.name_lower();
413 let msg = match source {
415 format!("{}, #[{}({})] on by default", msg,
416 level.as_str(), name)
419 format!("{} [-{} {}]", msg,
421 Warn => 'W', Deny => 'D', Forbid => 'F',
423 }, name.replace("_", "-"))
430 let release_channel = option_env!("CFG_RELEASE_CHANNEL").unwrap_or("(unknown)");
431 note = Some(format!("this feature may not be used in the {} release channel",
437 // For purposes of printing, we can treat forbid as deny.
438 if level == Forbid { level = Deny; }
440 match (level, span) {
441 (Warn, Some(sp)) => sess.span_warn(sp, &msg[]),
442 (Warn, None) => sess.warn(&msg[]),
443 (Deny, Some(sp)) => sess.span_err(sp, &msg[]),
444 (Deny, None) => sess.err(&msg[]),
445 _ => sess.bug("impossible level in raw_emit_lint"),
448 for note in note.into_iter() {
452 for span in def.into_iter() {
453 sess.span_note(span, "lint level defined here");
457 impl<'a, 'tcx> Context<'a, 'tcx> {
458 fn new(tcx: &'a ty::ctxt<'tcx>,
459 krate: &'a ast::Crate,
460 exported_items: &'a ExportedItems) -> Context<'a, 'tcx> {
461 // We want to own the lint store, so move it out of the session.
462 let lint_store = mem::replace(&mut *tcx.sess.lint_store.borrow_mut(),
468 exported_items: exported_items,
471 node_levels: RefCell::new(FnvHashMap()),
475 /// Get the overall compiler `Session` object.
476 pub fn sess(&'a self) -> &'a Session {
480 /// Get the level of `lint` at the current position of the lint
482 pub fn current_level(&self, lint: &'static Lint) -> Level {
483 self.lints.levels.get(&LintId::of(lint)).map_or(Allow, |&(lvl, _)| lvl)
486 fn lookup_and_emit(&self, lint: &'static Lint, span: Option<Span>, msg: &str) {
487 let (level, src) = match self.lints.levels.get(&LintId::of(lint)) {
489 Some(&(Warn, src)) => {
490 let lint_id = LintId::of(builtin::WARNINGS);
491 (self.lints.get_level_source(lint_id).0, src)
496 raw_emit_lint(&self.tcx.sess, lint, (level, src), span, msg);
499 /// Emit a lint at the appropriate level, with no associated span.
500 pub fn lint(&self, lint: &'static Lint, msg: &str) {
501 self.lookup_and_emit(lint, None, msg);
504 /// Emit a lint at the appropriate level, for a particular span.
505 pub fn span_lint(&self, lint: &'static Lint, span: Span, msg: &str) {
506 self.lookup_and_emit(lint, Some(span), msg);
509 /// Merge the lints specified by any lint attributes into the
510 /// current lint context, call the provided function, then reset the
511 /// lints in effect to their previous state.
512 fn with_lint_attrs<F>(&mut self,
513 attrs: &[ast::Attribute],
515 F: FnOnce(&mut Context),
517 // Parse all of the lint attributes, and then add them all to the
518 // current dictionary of lint information. Along the way, keep a history
519 // of what we changed so we can roll everything back after invoking the
523 for result in gather_attrs(attrs).into_iter() {
524 let v = match result {
526 self.tcx.sess.span_err(span, "malformed lint attribute");
529 Ok((lint_name, level, span)) => {
530 match self.lints.find_lint(lint_name.get(), &self.tcx.sess, Some(span)) {
531 Some(lint_id) => vec![(lint_id, level, span)],
533 match self.lints.lint_groups.get(lint_name.get()) {
534 Some(&(ref v, _)) => v.iter()
535 .map(|lint_id: &LintId|
536 (*lint_id, level, span))
539 self.span_lint(builtin::UNKNOWN_LINTS, span,
540 format!("unknown `{}` attribute: `{}`",
541 level.as_str(), lint_name).as_slice());
550 for (lint_id, level, span) in v.into_iter() {
551 let now = self.lints.get_level_source(lint_id).0;
552 if now == Forbid && level != Forbid {
553 let lint_name = lint_id.as_str();
554 self.tcx.sess.span_err(span,
555 &format!("{}({}) overruled by outer forbid({})",
556 level.as_str(), lint_name,
558 } else if now != level {
559 let src = self.lints.get_level_source(lint_id).1;
560 self.level_stack.push((lint_id, (now, src)));
562 self.lints.set_level(lint_id, (level, Node(span)));
567 run_lints!(self, enter_lint_attrs, attrs);
569 run_lints!(self, exit_lint_attrs, attrs);
572 for _ in range(0, pushed) {
573 let (lint, lvlsrc) = self.level_stack.pop().unwrap();
574 self.lints.set_level(lint, lvlsrc);
578 fn visit_ids<F>(&mut self, f: F) where
579 F: FnOnce(&mut ast_util::IdVisitor<Context>)
581 let mut v = ast_util::IdVisitor {
583 pass_through_items: false,
584 visited_outermost: false,
590 impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> {
591 fn visit_item(&mut self, it: &ast::Item) {
592 self.with_lint_attrs(&it.attrs[], |cx| {
593 run_lints!(cx, check_item, it);
594 cx.visit_ids(|v| v.visit_item(it));
595 visit::walk_item(cx, it);
599 fn visit_foreign_item(&mut self, it: &ast::ForeignItem) {
600 self.with_lint_attrs(&it.attrs[], |cx| {
601 run_lints!(cx, check_foreign_item, it);
602 visit::walk_foreign_item(cx, it);
606 fn visit_view_item(&mut self, i: &ast::ViewItem) {
607 self.with_lint_attrs(&i.attrs[], |cx| {
608 run_lints!(cx, check_view_item, i);
609 cx.visit_ids(|v| v.visit_view_item(i));
610 visit::walk_view_item(cx, i);
614 fn visit_pat(&mut self, p: &ast::Pat) {
615 run_lints!(self, check_pat, p);
616 visit::walk_pat(self, p);
619 fn visit_expr(&mut self, e: &ast::Expr) {
620 run_lints!(self, check_expr, e);
621 visit::walk_expr(self, e);
624 fn visit_stmt(&mut self, s: &ast::Stmt) {
625 run_lints!(self, check_stmt, s);
626 visit::walk_stmt(self, s);
629 fn visit_fn(&mut self, fk: FnKind<'v>, decl: &'v ast::FnDecl,
630 body: &'v ast::Block, span: Span, id: ast::NodeId) {
632 visit::FkMethod(_, _, m) => {
633 self.with_lint_attrs(&m.attrs[], |cx| {
634 run_lints!(cx, check_fn, fk, decl, body, span, id);
636 v.visit_fn(fk, decl, body, span, id);
638 visit::walk_fn(cx, fk, decl, body, span);
642 run_lints!(self, check_fn, fk, decl, body, span, id);
643 visit::walk_fn(self, fk, decl, body, span);
648 fn visit_ty_method(&mut self, t: &ast::TypeMethod) {
649 self.with_lint_attrs(&t.attrs[], |cx| {
650 run_lints!(cx, check_ty_method, t);
651 visit::walk_ty_method(cx, t);
655 fn visit_struct_def(&mut self,
660 run_lints!(self, check_struct_def, s, ident, g, id);
661 visit::walk_struct_def(self, s);
662 run_lints!(self, check_struct_def_post, s, ident, g, id);
665 fn visit_struct_field(&mut self, s: &ast::StructField) {
666 self.with_lint_attrs(&s.node.attrs[], |cx| {
667 run_lints!(cx, check_struct_field, s);
668 visit::walk_struct_field(cx, s);
672 fn visit_variant(&mut self, v: &ast::Variant, g: &ast::Generics) {
673 self.with_lint_attrs(&v.node.attrs[], |cx| {
674 run_lints!(cx, check_variant, v, g);
675 visit::walk_variant(cx, v, g);
676 run_lints!(cx, check_variant_post, v, g);
680 // FIXME(#10894) should continue recursing
681 fn visit_ty(&mut self, t: &ast::Ty) {
682 run_lints!(self, check_ty, t);
685 fn visit_ident(&mut self, sp: Span, id: ast::Ident) {
686 run_lints!(self, check_ident, sp, id);
689 fn visit_mod(&mut self, m: &ast::Mod, s: Span, n: ast::NodeId) {
690 run_lints!(self, check_mod, m, s, n);
691 visit::walk_mod(self, m);
694 fn visit_local(&mut self, l: &ast::Local) {
695 run_lints!(self, check_local, l);
696 visit::walk_local(self, l);
699 fn visit_block(&mut self, b: &ast::Block) {
700 run_lints!(self, check_block, b);
701 visit::walk_block(self, b);
704 fn visit_arm(&mut self, a: &ast::Arm) {
705 run_lints!(self, check_arm, a);
706 visit::walk_arm(self, a);
709 fn visit_decl(&mut self, d: &ast::Decl) {
710 run_lints!(self, check_decl, d);
711 visit::walk_decl(self, d);
714 fn visit_expr_post(&mut self, e: &ast::Expr) {
715 run_lints!(self, check_expr_post, e);
718 fn visit_generics(&mut self, g: &ast::Generics) {
719 run_lints!(self, check_generics, g);
720 visit::walk_generics(self, g);
723 fn visit_trait_item(&mut self, m: &ast::TraitItem) {
724 run_lints!(self, check_trait_method, m);
725 visit::walk_trait_item(self, m);
728 fn visit_opt_lifetime_ref(&mut self, sp: Span, lt: &Option<ast::Lifetime>) {
729 run_lints!(self, check_opt_lifetime_ref, sp, lt);
732 fn visit_lifetime_ref(&mut self, lt: &ast::Lifetime) {
733 run_lints!(self, check_lifetime_ref, lt);
736 fn visit_lifetime_def(&mut self, lt: &ast::LifetimeDef) {
737 run_lints!(self, check_lifetime_def, lt);
740 fn visit_explicit_self(&mut self, es: &ast::ExplicitSelf) {
741 run_lints!(self, check_explicit_self, es);
742 visit::walk_explicit_self(self, es);
745 fn visit_mac(&mut self, mac: &ast::Mac) {
746 run_lints!(self, check_mac, mac);
747 visit::walk_mac(self, mac);
750 fn visit_path(&mut self, p: &ast::Path, id: ast::NodeId) {
751 run_lints!(self, check_path, p, id);
752 visit::walk_path(self, p);
755 fn visit_attribute(&mut self, attr: &ast::Attribute) {
756 run_lints!(self, check_attribute, attr);
760 // Output any lints that were previously added to the session.
761 impl<'a, 'tcx> IdVisitingOperation for Context<'a, 'tcx> {
762 fn visit_id(&mut self, id: ast::NodeId) {
763 match self.tcx.sess.lints.borrow_mut().remove(&id) {
766 for (lint_id, span, msg) in lints.into_iter() {
767 self.span_lint(lint_id.lint, span, &msg[])
774 // This lint pass is defined here because it touches parts of the `Context`
775 // that we don't want to expose. It records the lint level at certain AST
776 // nodes, so that the variant size difference check in trans can call
779 struct GatherNodeLevels;
781 impl LintPass for GatherNodeLevels {
782 fn get_lints(&self) -> LintArray {
786 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
788 ast::ItemEnum(..) => {
789 let lint_id = LintId::of(builtin::VARIANT_SIZE_DIFFERENCES);
790 let lvlsrc = cx.lints.get_level_source(lint_id);
792 (lvl, _) if lvl != Allow => {
793 cx.node_levels.borrow_mut()
794 .insert((it.id, lint_id), lvlsrc);
804 /// Perform lint checking on a crate.
806 /// Consumes the `lint_store` field of the `Session`.
807 pub fn check_crate(tcx: &ty::ctxt,
808 exported_items: &ExportedItems) {
810 // If this is a feature-staged build of rustc then flip several lints to 'forbid'
811 tcx.sess.lint_store.borrow_mut().maybe_stage_features(&tcx.sess);
813 let krate = tcx.map.krate();
814 let mut cx = Context::new(tcx, krate, exported_items);
816 // Visit the whole crate.
817 cx.with_lint_attrs(&krate.attrs[], |cx| {
818 cx.visit_id(ast::CRATE_NODE_ID);
820 v.visited_outermost = true;
821 visit::walk_crate(v, krate);
824 // since the root module isn't visited as an item (because it isn't an
825 // item), warn for it here.
826 run_lints!(cx, check_crate, krate);
828 visit::walk_crate(cx, krate);
831 // If we missed any lints added to the session, then there's a bug somewhere
832 // in the iteration code.
833 for (id, v) in tcx.sess.lints.borrow().iter() {
834 for &(lint, span, ref msg) in v.iter() {
835 tcx.sess.span_bug(span,
836 format!("unprocessed lint {} at {}: {}",
837 lint.as_str(), tcx.map.node_to_string(*id), *msg).as_slice())
841 tcx.sess.abort_if_errors();
842 *tcx.node_lint_levels.borrow_mut() = cx.node_levels.into_inner();