1 //! Implementation of lint checking.
3 //! The lint checking is mostly consolidated into one pass which runs
4 //! after all other analyses. Throughout compilation, lint warnings
5 //! can be added via the `add_lint` method on the Session structure. This
6 //! requires a span and an ID of the node that the lint is being added to. The
7 //! lint isn't actually emitted at that time because it is unknown what the
8 //! actual lint level at that location is.
10 //! To actually emit lint warnings/errors, a separate pass is used.
11 //! A context keeps track of the current state of all lint levels.
12 //! Upon entering a node of the ast which can modify the lint settings, the
13 //! previous lint state is pushed onto a stack and the ast is then recursed
14 //! upon. As the ast is traversed, this keeps track of the current lint level
15 //! for all lint attributes.
17 use self::TargetLint::*;
19 use crate::levels::LintLevelsBuilder;
20 use crate::passes::{EarlyLintPassObject, LateLintPassObject};
22 use rustc_data_structures::fx::FxHashMap;
23 use rustc_data_structures::sync;
25 add_elided_lifetime_in_path_suggestion, struct_span_err, Applicability, SuggestionStyle,
28 use rustc_hir::def::Res;
29 use rustc_hir::def_id::{CrateNum, DefId};
30 use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
31 use rustc_middle::lint::LintDiagnosticBuilder;
32 use rustc_middle::middle::privacy::AccessLevels;
33 use rustc_middle::middle::stability;
34 use rustc_middle::ty::layout::{LayoutError, TyAndLayout};
35 use rustc_middle::ty::print::with_no_trimmed_paths;
36 use rustc_middle::ty::{self, print::Printer, subst::GenericArg, Ty, TyCtxt};
37 use rustc_serialize::json::Json;
38 use rustc_session::lint::{BuiltinLintDiagnostics, ExternDepSpec};
39 use rustc_session::lint::{FutureIncompatibleInfo, Level, Lint, LintBuffer, LintId};
40 use rustc_session::Session;
41 use rustc_session::SessionLintStore;
42 use rustc_span::lev_distance::find_best_match_for_name;
43 use rustc_span::{symbol::Symbol, MultiSpan, Span, DUMMY_SP};
44 use rustc_target::abi::LayoutOf;
50 /// Information about the registered lints.
52 /// This is basically the subset of `Context` that we can
53 /// build early in the compile pipeline.
54 pub struct LintStore {
56 lints: Vec<&'static Lint>,
58 /// Constructor functions for each variety of lint pass.
60 /// These should only be called once, but since we want to avoid locks or
61 /// interior mutability, we don't enforce this (and lints should, in theory,
62 /// be compatible with being constructed more than once, though not
63 /// necessarily in a sane manner. This is safe though.)
64 pub pre_expansion_passes: Vec<Box<dyn Fn() -> EarlyLintPassObject + sync::Send + sync::Sync>>,
65 pub early_passes: Vec<Box<dyn Fn() -> EarlyLintPassObject + sync::Send + sync::Sync>>,
66 pub late_passes: Vec<Box<dyn Fn() -> LateLintPassObject + sync::Send + sync::Sync>>,
67 /// This is unique in that we construct them per-module, so not once.
68 pub late_module_passes: Vec<Box<dyn Fn() -> LateLintPassObject + sync::Send + sync::Sync>>,
70 /// Lints indexed by name.
71 by_name: FxHashMap<String, TargetLint>,
73 /// Map of registered lint groups to what lints they expand to.
74 lint_groups: FxHashMap<&'static str, LintGroup>,
77 impl SessionLintStore for LintStore {
78 fn name_to_lint(&self, lint_name: &str) -> LintId {
80 .find_lints(lint_name)
81 .unwrap_or_else(|_| panic!("Failed to find lint with name `{}`", lint_name));
83 if let &[lint] = lints.as_slice() {
86 panic!("Found mutliple lints with name `{}`: {:?}", lint_name, lints);
91 /// The target of the `by_name` map, which accounts for renaming/deprecation.
94 /// A direct lint target
97 /// Temporary renaming, used for easing migration pain; see #16545
98 Renamed(String, LintId),
100 /// Lint with this name existed previously, but has been removed/deprecated.
101 /// The string argument is the reason for removal.
105 pub enum FindLintError {
112 /// Whether deprecation warnings should be suppressed for this alias.
117 lint_ids: Vec<LintId>,
119 depr: Option<LintAlias>,
122 pub enum CheckLintNameResult<'a> {
124 /// Lint doesn't exist. Potentially contains a suggestion for a correct lint name.
125 NoLint(Option<Symbol>),
126 /// The lint is either renamed or removed. This is the warning
127 /// message, and an optional new name (`None` if removed).
128 Warning(String, Option<String>),
129 /// The lint is from a tool. If the Option is None, then either
130 /// the lint does not exist in the tool or the code was not
131 /// compiled with the tool and therefore the lint was never
132 /// added to the `LintStore`. Otherwise the `LintId` will be
133 /// returned as if it where a rustc lint.
134 Tool(Result<&'a [LintId], (Option<&'a [LintId]>, String)>),
138 pub fn new() -> LintStore {
141 pre_expansion_passes: vec![],
142 early_passes: vec![],
144 late_module_passes: vec![],
145 by_name: Default::default(),
146 lint_groups: Default::default(),
150 pub fn get_lints<'t>(&'t self) -> &'t [&'static Lint] {
154 pub fn get_lint_groups<'t>(&'t self) -> Vec<(&'static str, Vec<LintId>, bool)> {
157 .filter(|(_, LintGroup { depr, .. })| {
158 // Don't display deprecated lint groups.
161 .map(|(k, LintGroup { lint_ids, from_plugin, .. })| {
162 (*k, lint_ids.clone(), *from_plugin)
167 pub fn register_early_pass(
169 pass: impl Fn() -> EarlyLintPassObject + 'static + sync::Send + sync::Sync,
171 self.early_passes.push(Box::new(pass));
174 pub fn register_pre_expansion_pass(
176 pass: impl Fn() -> EarlyLintPassObject + 'static + sync::Send + sync::Sync,
178 self.pre_expansion_passes.push(Box::new(pass));
181 pub fn register_late_pass(
183 pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync,
185 self.late_passes.push(Box::new(pass));
188 pub fn register_late_mod_pass(
190 pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync,
192 self.late_module_passes.push(Box::new(pass));
195 // Helper method for register_early/late_pass
196 pub fn register_lints(&mut self, lints: &[&'static Lint]) {
198 self.lints.push(lint);
200 let id = LintId::of(lint);
201 if self.by_name.insert(lint.name_lower(), Id(id)).is_some() {
202 bug!("duplicate specification of lint {}", lint.name_lower())
205 if let Some(FutureIncompatibleInfo { edition, .. }) = lint.future_incompatible {
206 if let Some(edition) = edition {
208 .entry(edition.lint_name())
209 .or_insert(LintGroup {
211 from_plugin: lint.is_plugin,
219 .entry("future_incompatible")
220 .or_insert(LintGroup {
222 from_plugin: lint.is_plugin,
231 pub fn register_group_alias(&mut self, lint_name: &'static str, alias: &'static str) {
232 self.lint_groups.insert(
237 depr: Some(LintAlias { name: lint_name, silent: true }),
242 pub fn register_group(
246 deprecated_name: Option<&'static str>,
251 .insert(name, LintGroup { lint_ids: to, from_plugin, depr: None })
253 if let Some(deprecated) = deprecated_name {
254 self.lint_groups.insert(
259 depr: Some(LintAlias { name, silent: false }),
265 bug!("duplicate specification of lint group {}", name);
270 pub fn register_renamed(&mut self, old_name: &str, new_name: &str) {
271 let target = match self.by_name.get(new_name) {
272 Some(&Id(lint_id)) => lint_id,
273 _ => bug!("invalid lint renaming of {} to {}", old_name, new_name),
275 self.by_name.insert(old_name.to_string(), Renamed(new_name.to_string(), target));
278 pub fn register_removed(&mut self, name: &str, reason: &str) {
279 self.by_name.insert(name.into(), Removed(reason.into()));
282 pub fn find_lints(&self, mut lint_name: &str) -> Result<Vec<LintId>, FindLintError> {
283 match self.by_name.get(lint_name) {
284 Some(&Id(lint_id)) => Ok(vec![lint_id]),
285 Some(&Renamed(_, lint_id)) => Ok(vec![lint_id]),
286 Some(&Removed(_)) => Err(FindLintError::Removed),
288 return match self.lint_groups.get(lint_name) {
289 Some(LintGroup { lint_ids, depr, .. }) => {
290 if let Some(LintAlias { name, .. }) = depr {
296 None => Err(FindLintError::Removed),
302 /// Checks the validity of lint names derived from the command line
303 pub fn check_lint_name_cmdline(&self, sess: &Session, lint_name: &str, level: Level) {
304 let db = match self.check_lint_name(lint_name, None) {
305 CheckLintNameResult::Ok(_) => None,
306 CheckLintNameResult::Warning(ref msg, _) => Some(sess.struct_warn(msg)),
307 CheckLintNameResult::NoLint(suggestion) => {
309 struct_span_err!(sess, DUMMY_SP, E0602, "unknown lint: `{}`", lint_name);
311 if let Some(suggestion) = suggestion {
312 err.help(&format!("did you mean: `{}`", suggestion));
317 CheckLintNameResult::Tool(result) => match result {
318 Err((Some(_), new_name)) => Some(sess.struct_warn(&format!(
319 "lint name `{}` is deprecated \
320 and does not have an effect anymore. \
328 if let Some(mut db) = db {
330 "requested on the command line with `{} {}`",
332 Level::Allow => "-A",
335 Level::Forbid => "-F",
344 /// True if this symbol represents a lint group name.
345 pub fn is_lint_group(&self, lint_name: Symbol) -> bool {
347 "is_lint_group(lint_name={:?}, lint_groups={:?})",
349 self.lint_groups.keys().collect::<Vec<_>>()
351 let lint_name_str = &*lint_name.as_str();
352 self.lint_groups.contains_key(&lint_name_str) || {
353 let warnings_name_str = crate::WARNINGS.name_lower();
354 lint_name_str == &*warnings_name_str
358 /// Checks the name of a lint for its existence, and whether it was
359 /// renamed or removed. Generates a DiagnosticBuilder containing a
360 /// warning for renamed and removed lints. This is over both lint
361 /// names from attributes and those passed on the command line. Since
362 /// it emits non-fatal warnings and there are *two* lint passes that
363 /// inspect attributes, this is only run from the late pass to avoid
364 /// printing duplicate warnings.
365 pub fn check_lint_name(
368 tool_name: Option<Symbol>,
369 ) -> CheckLintNameResult<'_> {
370 let complete_name = if let Some(tool_name) = tool_name {
371 format!("{}::{}", tool_name, lint_name)
373 lint_name.to_string()
375 // If the lint was scoped with `tool::` check if the tool lint exists
376 if let Some(tool_name) = tool_name {
377 match self.by_name.get(&complete_name) {
378 None => match self.lint_groups.get(&*complete_name) {
379 // If the lint isn't registered, there are two possibilities:
381 // 1. The tool is currently running, so this lint really doesn't exist.
382 // FIXME: should this handle tools that never register a lint, like rustfmt?
383 tracing::debug!("lints={:?}", self.by_name.keys().collect::<Vec<_>>());
384 let tool_prefix = format!("{}::", tool_name);
385 return if self.by_name.keys().any(|lint| lint.starts_with(&tool_prefix)) {
386 self.no_lint_suggestion(&complete_name)
388 // 2. The tool isn't currently running, so no lints will be registered.
389 // To avoid giving a false positive, ignore all unknown lints.
390 CheckLintNameResult::Tool(Err((None, String::new())))
393 Some(LintGroup { lint_ids, .. }) => {
394 return CheckLintNameResult::Tool(Ok(&lint_ids));
397 Some(&Id(ref id)) => return CheckLintNameResult::Tool(Ok(slice::from_ref(id))),
398 // If the lint was registered as removed or renamed by the lint tool, we don't need
399 // to treat tool_lints and rustc lints different and can use the code below.
403 match self.by_name.get(&complete_name) {
404 Some(&Renamed(ref new_name, _)) => CheckLintNameResult::Warning(
405 format!("lint `{}` has been renamed to `{}`", complete_name, new_name),
406 Some(new_name.to_owned()),
408 Some(&Removed(ref reason)) => CheckLintNameResult::Warning(
409 format!("lint `{}` has been removed: {}", complete_name, reason),
412 None => match self.lint_groups.get(&*complete_name) {
413 // If neither the lint, nor the lint group exists check if there is a `clippy::`
414 // variant of this lint
415 None => self.check_tool_name_for_backwards_compat(&complete_name, "clippy"),
416 Some(LintGroup { lint_ids, depr, .. }) => {
417 // Check if the lint group name is deprecated
418 if let Some(LintAlias { name, silent }) = depr {
419 let LintGroup { lint_ids, .. } = self.lint_groups.get(name).unwrap();
421 CheckLintNameResult::Ok(&lint_ids)
423 CheckLintNameResult::Tool(Err((Some(&lint_ids), (*name).to_string())))
426 CheckLintNameResult::Ok(&lint_ids)
429 Some(&Id(ref id)) => CheckLintNameResult::Ok(slice::from_ref(id)),
433 fn no_lint_suggestion(&self, lint_name: &str) -> CheckLintNameResult<'_> {
434 let name_lower = lint_name.to_lowercase();
436 self.get_lints().iter().map(|l| Symbol::intern(&l.name_lower())).collect::<Vec<_>>();
438 if lint_name.chars().any(char::is_uppercase) && self.find_lints(&name_lower).is_ok() {
439 // First check if the lint name is (partly) in upper case instead of lower case...
440 CheckLintNameResult::NoLint(Some(Symbol::intern(&name_lower)))
442 // ...if not, search for lints with a similar name
443 let suggestion = find_best_match_for_name(&symbols, Symbol::intern(&name_lower), None);
444 CheckLintNameResult::NoLint(suggestion)
448 fn check_tool_name_for_backwards_compat(
452 ) -> CheckLintNameResult<'_> {
453 let complete_name = format!("{}::{}", tool_name, lint_name);
454 match self.by_name.get(&complete_name) {
455 None => match self.lint_groups.get(&*complete_name) {
456 // Now we are sure, that this lint exists nowhere
457 None => self.no_lint_suggestion(lint_name),
458 Some(LintGroup { lint_ids, depr, .. }) => {
459 // Reaching this would be weird, but let's cover this case anyway
460 if let Some(LintAlias { name, silent }) = depr {
461 let LintGroup { lint_ids, .. } = self.lint_groups.get(name).unwrap();
463 CheckLintNameResult::Tool(Err((Some(&lint_ids), complete_name)))
465 CheckLintNameResult::Tool(Err((Some(&lint_ids), (*name).to_string())))
468 CheckLintNameResult::Tool(Err((Some(&lint_ids), complete_name)))
471 Some(&Id(ref id)) => {
472 CheckLintNameResult::Tool(Err((Some(slice::from_ref(id)), complete_name)))
475 tracing::debug!("got renamed lint {:?}", other);
476 CheckLintNameResult::NoLint(None)
482 /// Context for lint checking after type checking.
483 pub struct LateContext<'tcx> {
484 /// Type context we're checking in.
485 pub tcx: TyCtxt<'tcx>,
487 /// Current body, or `None` if outside a body.
488 pub enclosing_body: Option<hir::BodyId>,
490 /// Type-checking results for the current body. Access using the `typeck_results`
491 /// and `maybe_typeck_results` methods, which handle querying the typeck results on demand.
492 // FIXME(eddyb) move all the code accessing internal fields like this,
493 // to this module, to avoid exposing it to lint logic.
494 pub(super) cached_typeck_results: Cell<Option<&'tcx ty::TypeckResults<'tcx>>>,
496 /// Parameter environment for the item we are in.
497 pub param_env: ty::ParamEnv<'tcx>,
499 /// Items accessible from the crate being checked.
500 pub access_levels: &'tcx AccessLevels,
502 /// The store of registered lints and the lint levels.
503 pub lint_store: &'tcx LintStore,
505 pub last_node_with_lint_attrs: hir::HirId,
507 /// Generic type parameters in scope for the item we are in.
508 pub generics: Option<&'tcx hir::Generics<'tcx>>,
510 /// We are only looking at one module
511 pub only_module: bool,
514 /// Context for lint checking of the AST, after expansion, before lowering to
516 pub struct EarlyContext<'a> {
517 /// Type context we're checking in.
518 pub sess: &'a Session,
520 /// The crate being checked.
521 pub krate: &'a ast::Crate,
523 pub builder: LintLevelsBuilder<'a>,
525 /// The store of registered lints and the lint levels.
526 pub lint_store: &'a LintStore,
528 pub buffered: LintBuffer,
531 pub trait LintPassObject: Sized {}
533 impl LintPassObject for EarlyLintPassObject {}
535 impl LintPassObject for LateLintPassObject {}
537 pub trait LintContext: Sized {
538 type PassObject: LintPassObject;
540 fn sess(&self) -> &Session;
541 fn lints(&self) -> &LintStore;
543 fn lookup_with_diagnostics(
546 span: Option<impl Into<MultiSpan>>,
547 decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a>),
548 diagnostic: BuiltinLintDiagnostics,
550 self.lookup(lint, span, |lint| {
551 // We first generate a blank diagnostic.
552 let mut db = lint.build("");
554 // Now, set up surrounding context.
555 let sess = self.sess();
557 BuiltinLintDiagnostics::Normal => (),
558 BuiltinLintDiagnostics::BareTraitObject(span, is_global) => {
559 let (sugg, app) = match sess.source_map().span_to_snippet(span) {
560 Ok(s) if is_global => {
561 (format!("dyn ({})", s), Applicability::MachineApplicable)
563 Ok(s) => (format!("dyn {}", s), Applicability::MachineApplicable),
564 Err(_) => ("dyn <type>".to_string(), Applicability::HasPlaceholders),
566 db.span_suggestion(span, "use `dyn`", sugg, app);
568 BuiltinLintDiagnostics::AbsPathWithModule(span) => {
569 let (sugg, app) = match sess.source_map().span_to_snippet(span) {
571 // FIXME(Manishearth) ideally the emitting code
572 // can tell us whether or not this is global
574 if s.trim_start().starts_with("::") { "" } else { "::" };
576 (format!("crate{}{}", opt_colon, s), Applicability::MachineApplicable)
578 Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
580 db.span_suggestion(span, "use `crate`", sugg, app);
582 BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(span) => {
585 "names from parent modules are not accessible without an explicit import",
588 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(
591 db.span_note(span_def, "the macro is defined here");
593 BuiltinLintDiagnostics::ElidedLifetimesInPaths(
600 add_elided_lifetime_in_path_suggestion(
610 BuiltinLintDiagnostics::UnknownCrateTypes(span, note, sugg) => {
611 db.span_suggestion(span, ¬e, sugg, Applicability::MaybeIncorrect);
613 BuiltinLintDiagnostics::UnusedImports(message, replaces) => {
614 if !replaces.is_empty() {
615 db.tool_only_multipart_suggestion(
618 Applicability::MachineApplicable,
622 BuiltinLintDiagnostics::RedundantImport(spans, ident) => {
623 for (span, is_imported) in spans {
624 let introduced = if is_imported { "imported" } else { "defined" };
627 format!("the item `{}` is already {} here", ident, introduced),
631 BuiltinLintDiagnostics::DeprecatedMacro(suggestion, span) => {
632 stability::deprecation_suggestion(&mut db, "macro", suggestion, span)
634 BuiltinLintDiagnostics::UnusedDocComment(span) => {
635 db.span_label(span, "rustdoc does not generate documentation for macro invocations");
636 db.help("to document an item produced by a macro, \
637 the macro must produce the documentation as part of its expansion");
639 BuiltinLintDiagnostics::PatternsInFnsWithoutBody(span, ident) => {
640 db.span_suggestion(span, "remove `mut` from the parameter", ident.to_string(), Applicability::MachineApplicable);
642 BuiltinLintDiagnostics::MissingAbi(span, default_abi) => {
643 db.span_label(span, "ABI should be specified here");
644 db.help(&format!("the default ABI is {}", default_abi.name()));
646 BuiltinLintDiagnostics::LegacyDeriveHelpers(span) => {
647 db.span_label(span, "the attribute is introduced here");
649 BuiltinLintDiagnostics::ExternDepSpec(krate, loc) => {
650 let json = match loc {
651 ExternDepSpec::Json(json) => {
652 db.help(&format!("remove unnecessary dependency `{}`", krate));
655 ExternDepSpec::Raw(raw) => {
656 db.help(&format!("remove unnecessary dependency `{}` at `{}`", krate, raw));
657 db.span_suggestion_with_style(
659 "raw extern location",
661 Applicability::Unspecified,
662 SuggestionStyle::CompletelyHidden,
667 db.tool_only_suggestion_with_metadata(
668 "json extern location",
669 Applicability::Unspecified,
674 // Rewrap `db`, and pass control to the user.
675 decorate(LintDiagnosticBuilder::new(db));
679 // FIXME: These methods should not take an Into<MultiSpan> -- instead, callers should need to
680 // set the span in their `decorate` function (preferably using set_span).
681 fn lookup<S: Into<MultiSpan>>(
685 decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a>),
688 fn struct_span_lint<S: Into<MultiSpan>>(
692 decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a>),
694 self.lookup(lint, Some(span), decorate);
696 /// Emit a lint at the appropriate level, with no associated span.
697 fn lint(&self, lint: &'static Lint, decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a>)) {
698 self.lookup(lint, None as Option<Span>, decorate);
702 impl<'a> EarlyContext<'a> {
705 lint_store: &'a LintStore,
706 krate: &'a ast::Crate,
707 buffered: LintBuffer,
708 warn_about_weird_lints: bool,
709 ) -> EarlyContext<'a> {
714 builder: LintLevelsBuilder::new(sess, warn_about_weird_lints, lint_store),
720 impl LintContext for LateContext<'_> {
721 type PassObject = LateLintPassObject;
723 /// Gets the overall compiler `Session` object.
724 fn sess(&self) -> &Session {
728 fn lints(&self) -> &LintStore {
732 fn lookup<S: Into<MultiSpan>>(
736 decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a>),
738 let hir_id = self.last_node_with_lint_attrs;
741 Some(s) => self.tcx.struct_span_lint_hir(lint, hir_id, s, decorate),
742 None => self.tcx.struct_lint_node(lint, hir_id, decorate),
747 impl LintContext for EarlyContext<'_> {
748 type PassObject = EarlyLintPassObject;
750 /// Gets the overall compiler `Session` object.
751 fn sess(&self) -> &Session {
755 fn lints(&self) -> &LintStore {
759 fn lookup<S: Into<MultiSpan>>(
763 decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a>),
765 self.builder.struct_lint(lint, span.map(|s| s.into()), decorate)
769 impl<'tcx> LateContext<'tcx> {
770 /// Gets the type-checking results for the current body,
771 /// or `None` if outside a body.
772 pub fn maybe_typeck_results(&self) -> Option<&'tcx ty::TypeckResults<'tcx>> {
773 self.cached_typeck_results.get().or_else(|| {
774 self.enclosing_body.map(|body| {
775 let typeck_results = self.tcx.typeck_body(body);
776 self.cached_typeck_results.set(Some(typeck_results));
782 /// Gets the type-checking results for the current body.
783 /// As this will ICE if called outside bodies, only call when working with
784 /// `Expr` or `Pat` nodes (they are guaranteed to be found only in bodies).
786 pub fn typeck_results(&self) -> &'tcx ty::TypeckResults<'tcx> {
787 self.maybe_typeck_results().expect("`LateContext::typeck_results` called outside of body")
790 /// Returns the final resolution of a `QPath`, or `Res::Err` if unavailable.
791 /// Unlike `.typeck_results().qpath_res(qpath, id)`, this can be used even outside
792 /// bodies (e.g. for paths in `hir::Ty`), without any risk of ICE-ing.
793 pub fn qpath_res(&self, qpath: &hir::QPath<'_>, id: hir::HirId) -> Res {
795 hir::QPath::Resolved(_, ref path) => path.res,
796 hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => self
797 .maybe_typeck_results()
798 .filter(|typeck_results| typeck_results.hir_owner == id.owner)
800 if self.tcx.has_typeck_results(id.owner.to_def_id()) {
801 Some(self.tcx.typeck(id.owner))
806 .and_then(|typeck_results| typeck_results.type_dependent_def(id))
807 .map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)),
811 /// Check if a `DefId`'s path matches the given absolute type path usage.
813 /// Anonymous scopes such as `extern` imports are matched with `kw::Empty`;
814 /// inherent `impl` blocks are matched with the name of the type.
816 /// Instead of using this method, it is often preferable to instead use
817 /// `rustc_diagnostic_item` or a `lang_item`. This is less prone to errors
818 /// as paths get invalidated if the target definition moves.
822 /// ```rust,ignore (no context or def id available)
823 /// if cx.match_def_path(def_id, &[sym::core, sym::option, sym::Option]) {
824 /// // The given `def_id` is that of an `Option` type
827 pub fn match_def_path(&self, def_id: DefId, path: &[Symbol]) -> bool {
828 let names = self.get_def_path(def_id);
830 names.len() == path.len() && names.into_iter().zip(path.iter()).all(|(a, &b)| a == b)
833 /// Gets the absolute path of `def_id` as a vector of `Symbol`.
837 /// ```rust,ignore (no context or def id available)
838 /// let def_path = cx.get_def_path(def_id);
839 /// if let &[sym::core, sym::option, sym::Option] = &def_path[..] {
840 /// // The given `def_id` is that of an `Option` type
843 pub fn get_def_path(&self, def_id: DefId) -> Vec<Symbol> {
844 pub struct AbsolutePathPrinter<'tcx> {
845 pub tcx: TyCtxt<'tcx>,
848 impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
851 type Path = Vec<Symbol>;
854 type DynExistential = ();
857 fn tcx(&self) -> TyCtxt<'tcx> {
861 fn print_region(self, _region: ty::Region<'_>) -> Result<Self::Region, Self::Error> {
865 fn print_type(self, _ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> {
869 fn print_dyn_existential(
871 _predicates: &'tcx ty::List<ty::Binder<ty::ExistentialPredicate<'tcx>>>,
872 ) -> Result<Self::DynExistential, Self::Error> {
876 fn print_const(self, _ct: &'tcx ty::Const<'tcx>) -> Result<Self::Const, Self::Error> {
880 fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
881 Ok(vec![self.tcx.original_crate_name(cnum)])
887 trait_ref: Option<ty::TraitRef<'tcx>>,
888 ) -> Result<Self::Path, Self::Error> {
889 if trait_ref.is_none() {
890 if let ty::Adt(def, substs) = self_ty.kind() {
891 return self.print_def_path(def.did, substs);
895 // This shouldn't ever be needed, but just in case:
896 with_no_trimmed_paths(|| {
897 Ok(vec![match trait_ref {
898 Some(trait_ref) => Symbol::intern(&format!("{:?}", trait_ref)),
899 None => Symbol::intern(&format!("<{}>", self_ty)),
906 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
907 _disambiguated_data: &DisambiguatedDefPathData,
909 trait_ref: Option<ty::TraitRef<'tcx>>,
910 ) -> Result<Self::Path, Self::Error> {
911 let mut path = print_prefix(self)?;
913 // This shouldn't ever be needed, but just in case:
914 path.push(match trait_ref {
915 Some(trait_ref) => with_no_trimmed_paths(|| {
916 Symbol::intern(&format!(
918 trait_ref.print_only_trait_path(),
923 with_no_trimmed_paths(|| Symbol::intern(&format!("<impl {}>", self_ty)))
932 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
933 disambiguated_data: &DisambiguatedDefPathData,
934 ) -> Result<Self::Path, Self::Error> {
935 let mut path = print_prefix(self)?;
937 // Skip `::{{constructor}}` on tuple/unit structs.
938 if let DefPathData::Ctor = disambiguated_data.data {
942 path.push(Symbol::intern(&disambiguated_data.data.to_string()));
946 fn path_generic_args(
948 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
949 _args: &[GenericArg<'tcx>],
950 ) -> Result<Self::Path, Self::Error> {
955 AbsolutePathPrinter { tcx: self.tcx }.print_def_path(def_id, &[]).unwrap()
959 impl<'tcx> LayoutOf for LateContext<'tcx> {
961 type TyAndLayout = Result<TyAndLayout<'tcx>, LayoutError<'tcx>>;
963 fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyAndLayout {
964 self.tcx.layout_of(self.param_env.and(ty))