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_ast
::util
::lev_distance
::find_best_match_for_name
;
23 use rustc_data_structures
::fx
::FxHashMap
;
24 use rustc_data_structures
::sync
;
25 use rustc_errors
::{add_elided_lifetime_in_path_suggestion, struct_span_err, Applicability}
;
27 use rustc_hir
::def
::Res
;
28 use rustc_hir
::def_id
::{CrateNum, DefId}
;
29 use rustc_hir
::definitions
::{DefPathData, DisambiguatedDefPathData}
;
30 use rustc_middle
::lint
::LintDiagnosticBuilder
;
31 use rustc_middle
::middle
::privacy
::AccessLevels
;
32 use rustc_middle
::middle
::stability
;
33 use rustc_middle
::ty
::layout
::{LayoutError, TyAndLayout}
;
34 use rustc_middle
::ty
::print
::with_no_trimmed_paths
;
35 use rustc_middle
::ty
::{self, print::Printer, subst::GenericArg, Ty, TyCtxt}
;
36 use rustc_session
::lint
::BuiltinLintDiagnostics
;
37 use rustc_session
::lint
::{FutureIncompatibleInfo, Level, Lint, LintBuffer, LintId}
;
38 use rustc_session
::Session
;
39 use rustc_session
::SessionLintStore
;
40 use rustc_span
::{symbol::Symbol, MultiSpan, Span, DUMMY_SP}
;
41 use rustc_target
::abi
::LayoutOf
;
46 /// Information about the registered lints.
48 /// This is basically the subset of `Context` that we can
49 /// build early in the compile pipeline.
50 pub struct LintStore
{
52 lints
: Vec
<&'
static Lint
>,
54 /// Constructor functions for each variety of lint pass.
56 /// These should only be called once, but since we want to avoid locks or
57 /// interior mutability, we don't enforce this (and lints should, in theory,
58 /// be compatible with being constructed more than once, though not
59 /// necessarily in a sane manner. This is safe though.)
60 pub pre_expansion_passes
: Vec
<Box
<dyn Fn() -> EarlyLintPassObject
+ sync
::Send
+ sync
::Sync
>>,
61 pub early_passes
: Vec
<Box
<dyn Fn() -> EarlyLintPassObject
+ sync
::Send
+ sync
::Sync
>>,
62 pub late_passes
: Vec
<Box
<dyn Fn() -> LateLintPassObject
+ sync
::Send
+ sync
::Sync
>>,
63 /// This is unique in that we construct them per-module, so not once.
64 pub late_module_passes
: Vec
<Box
<dyn Fn() -> LateLintPassObject
+ sync
::Send
+ sync
::Sync
>>,
66 /// Lints indexed by name.
67 by_name
: FxHashMap
<String
, TargetLint
>,
69 /// Map of registered lint groups to what lints they expand to.
70 lint_groups
: FxHashMap
<&'
static str, LintGroup
>,
73 impl SessionLintStore
for LintStore
{
74 fn name_to_lint(&self, lint_name
: &str) -> LintId
{
76 .find_lints(lint_name
)
77 .unwrap_or_else(|_
| panic
!("Failed to find lint with name `{}`", lint_name
));
79 if let &[lint
] = lints
.as_slice() {
82 panic
!("Found mutliple lints with name `{}`: {:?}", lint_name
, lints
);
87 /// The target of the `by_name` map, which accounts for renaming/deprecation.
89 /// A direct lint target
92 /// Temporary renaming, used for easing migration pain; see #16545
93 Renamed(String
, LintId
),
95 /// Lint with this name existed previously, but has been removed/deprecated.
96 /// The string argument is the reason for removal.
100 pub enum FindLintError
{
107 /// Whether deprecation warnings should be suppressed for this alias.
112 lint_ids
: Vec
<LintId
>,
114 depr
: Option
<LintAlias
>,
117 pub enum CheckLintNameResult
<'a
> {
119 /// Lint doesn't exist. Potentially contains a suggestion for a correct lint name.
120 NoLint(Option
<Symbol
>),
121 /// The lint is either renamed or removed. This is the warning
122 /// message, and an optional new name (`None` if removed).
123 Warning(String
, Option
<String
>),
124 /// The lint is from a tool. If the Option is None, then either
125 /// the lint does not exist in the tool or the code was not
126 /// compiled with the tool and therefore the lint was never
127 /// added to the `LintStore`. Otherwise the `LintId` will be
128 /// returned as if it where a rustc lint.
129 Tool(Result
<&'a
[LintId
], (Option
<&'a
[LintId
]>, String
)>),
133 pub fn new() -> LintStore
{
136 pre_expansion_passes
: vec
![],
137 early_passes
: vec
![],
139 late_module_passes
: vec
![],
140 by_name
: Default
::default(),
141 lint_groups
: Default
::default(),
145 pub fn get_lints
<'t
>(&'t
self) -> &'t
[&'
static Lint
] {
149 pub fn get_lint_groups
<'t
>(&'t
self) -> Vec
<(&'
static str, Vec
<LintId
>, bool
)> {
152 .filter(|(_
, LintGroup { depr, .. }
)| {
153 // Don't display deprecated lint groups.
156 .map(|(k
, LintGroup { lint_ids, from_plugin, .. }
)| {
157 (*k
, lint_ids
.clone(), *from_plugin
)
162 pub fn register_early_pass(
164 pass
: impl Fn() -> EarlyLintPassObject
+ '
static + sync
::Send
+ sync
::Sync
,
166 self.early_passes
.push(Box
::new(pass
));
169 pub fn register_pre_expansion_pass(
171 pass
: impl Fn() -> EarlyLintPassObject
+ '
static + sync
::Send
+ sync
::Sync
,
173 self.pre_expansion_passes
.push(Box
::new(pass
));
176 pub fn register_late_pass(
178 pass
: impl Fn() -> LateLintPassObject
+ '
static + sync
::Send
+ sync
::Sync
,
180 self.late_passes
.push(Box
::new(pass
));
183 pub fn register_late_mod_pass(
185 pass
: impl Fn() -> LateLintPassObject
+ '
static + sync
::Send
+ sync
::Sync
,
187 self.late_module_passes
.push(Box
::new(pass
));
190 // Helper method for register_early/late_pass
191 pub fn register_lints(&mut self, lints
: &[&'
static Lint
]) {
193 self.lints
.push(lint
);
195 let id
= LintId
::of(lint
);
196 if self.by_name
.insert(lint
.name_lower(), Id(id
)).is_some() {
197 bug
!("duplicate specification of lint {}", lint
.name_lower())
200 if let Some(FutureIncompatibleInfo { edition, .. }
) = lint
.future_incompatible
{
201 if let Some(edition
) = edition
{
203 .entry(edition
.lint_name())
204 .or_insert(LintGroup
{
206 from_plugin
: lint
.is_plugin
,
214 .entry("future_incompatible")
215 .or_insert(LintGroup
{
217 from_plugin
: lint
.is_plugin
,
226 pub fn register_group_alias(&mut self, lint_name
: &'
static str, alias
: &'
static str) {
227 self.lint_groups
.insert(
232 depr
: Some(LintAlias { name: lint_name, silent: true }
),
237 pub fn register_group(
241 deprecated_name
: Option
<&'
static str>,
246 .insert(name
, LintGroup { lint_ids: to, from_plugin, depr: None }
)
248 if let Some(deprecated
) = deprecated_name
{
249 self.lint_groups
.insert(
254 depr
: Some(LintAlias { name, silent: false }
),
260 bug
!("duplicate specification of lint group {}", name
);
264 pub fn register_renamed(&mut self, old_name
: &str, new_name
: &str) {
265 let target
= match self.by_name
.get(new_name
) {
266 Some(&Id(lint_id
)) => lint_id
,
267 _
=> bug
!("invalid lint renaming of {} to {}", old_name
, new_name
),
269 self.by_name
.insert(old_name
.to_string(), Renamed(new_name
.to_string(), target
));
272 pub fn register_removed(&mut self, name
: &str, reason
: &str) {
273 self.by_name
.insert(name
.into(), Removed(reason
.into()));
276 pub fn find_lints(&self, mut lint_name
: &str) -> Result
<Vec
<LintId
>, FindLintError
> {
277 match self.by_name
.get(lint_name
) {
278 Some(&Id(lint_id
)) => Ok(vec
![lint_id
]),
279 Some(&Renamed(_
, lint_id
)) => Ok(vec
![lint_id
]),
280 Some(&Removed(_
)) => Err(FindLintError
::Removed
),
282 return match self.lint_groups
.get(lint_name
) {
283 Some(LintGroup { lint_ids, depr, .. }
) => {
284 if let Some(LintAlias { name, .. }
) = depr
{
290 None
=> Err(FindLintError
::Removed
),
296 /// Checks the validity of lint names derived from the command line
297 pub fn check_lint_name_cmdline(&self, sess
: &Session
, lint_name
: &str, level
: Level
) {
298 let db
= match self.check_lint_name(lint_name
, None
) {
299 CheckLintNameResult
::Ok(_
) => None
,
300 CheckLintNameResult
::Warning(ref msg
, _
) => Some(sess
.struct_warn(msg
)),
301 CheckLintNameResult
::NoLint(suggestion
) => {
303 struct_span_err
!(sess
, DUMMY_SP
, E0602
, "unknown lint: `{}`", lint_name
);
305 if let Some(suggestion
) = suggestion
{
306 err
.help(&format
!("did you mean: `{}`", suggestion
));
311 CheckLintNameResult
::Tool(result
) => match result
{
312 Err((Some(_
), new_name
)) => Some(sess
.struct_warn(&format
!(
313 "lint name `{}` is deprecated \
314 and does not have an effect anymore. \
322 if let Some(mut db
) = db
{
324 "requested on the command line with `{} {}`",
326 Level
::Allow
=> "-A",
329 Level
::Forbid
=> "-F",
338 /// Checks the name of a lint for its existence, and whether it was
339 /// renamed or removed. Generates a DiagnosticBuilder containing a
340 /// warning for renamed and removed lints. This is over both lint
341 /// names from attributes and those passed on the command line. Since
342 /// it emits non-fatal warnings and there are *two* lint passes that
343 /// inspect attributes, this is only run from the late pass to avoid
344 /// printing duplicate warnings.
345 pub fn check_lint_name(
348 tool_name
: Option
<Symbol
>,
349 ) -> CheckLintNameResult
<'_
> {
350 let complete_name
= if let Some(tool_name
) = tool_name
{
351 format
!("{}::{}", tool_name
, lint_name
)
353 lint_name
.to_string()
355 // If the lint was scoped with `tool::` check if the tool lint exists
356 if tool_name
.is_some() {
357 match self.by_name
.get(&complete_name
) {
358 None
=> match self.lint_groups
.get(&*complete_name
) {
359 None
=> return CheckLintNameResult
::Tool(Err((None
, String
::new()))),
360 Some(LintGroup { lint_ids, .. }
) => {
361 return CheckLintNameResult
::Tool(Ok(&lint_ids
));
364 Some(&Id(ref id
)) => return CheckLintNameResult
::Tool(Ok(slice
::from_ref(id
))),
365 // If the lint was registered as removed or renamed by the lint tool, we don't need
366 // to treat tool_lints and rustc lints different and can use the code below.
370 match self.by_name
.get(&complete_name
) {
371 Some(&Renamed(ref new_name
, _
)) => CheckLintNameResult
::Warning(
372 format
!("lint `{}` has been renamed to `{}`", complete_name
, new_name
),
373 Some(new_name
.to_owned()),
375 Some(&Removed(ref reason
)) => CheckLintNameResult
::Warning(
376 format
!("lint `{}` has been removed: `{}`", complete_name
, reason
),
379 None
=> match self.lint_groups
.get(&*complete_name
) {
380 // If neither the lint, nor the lint group exists check if there is a `clippy::`
381 // variant of this lint
382 None
=> self.check_tool_name_for_backwards_compat(&complete_name
, "clippy"),
383 Some(LintGroup { lint_ids, depr, .. }
) => {
384 // Check if the lint group name is deprecated
385 if let Some(LintAlias { name, silent }
) = depr
{
386 let LintGroup { lint_ids, .. }
= self.lint_groups
.get(name
).unwrap();
388 CheckLintNameResult
::Ok(&lint_ids
)
390 CheckLintNameResult
::Tool(Err((Some(&lint_ids
), (*name
).to_string())))
393 CheckLintNameResult
::Ok(&lint_ids
)
396 Some(&Id(ref id
)) => CheckLintNameResult
::Ok(slice
::from_ref(id
)),
400 fn check_tool_name_for_backwards_compat(
404 ) -> CheckLintNameResult
<'_
> {
405 let complete_name
= format
!("{}::{}", tool_name
, lint_name
);
406 match self.by_name
.get(&complete_name
) {
407 None
=> match self.lint_groups
.get(&*complete_name
) {
408 // Now we are sure, that this lint exists nowhere
411 self.by_name
.keys().map(|name
| Symbol
::intern(&name
)).collect
::<Vec
<_
>>();
413 let suggestion
= find_best_match_for_name(
415 Symbol
::intern(&lint_name
.to_lowercase()),
419 CheckLintNameResult
::NoLint(suggestion
)
421 Some(LintGroup { lint_ids, depr, .. }
) => {
422 // Reaching this would be weird, but let's cover this case anyway
423 if let Some(LintAlias { name, silent }
) = depr
{
424 let LintGroup { lint_ids, .. }
= self.lint_groups
.get(name
).unwrap();
426 CheckLintNameResult
::Tool(Err((Some(&lint_ids
), complete_name
)))
428 CheckLintNameResult
::Tool(Err((Some(&lint_ids
), (*name
).to_string())))
431 CheckLintNameResult
::Tool(Err((Some(&lint_ids
), complete_name
)))
434 Some(&Id(ref id
)) => {
435 CheckLintNameResult
::Tool(Err((Some(slice
::from_ref(id
)), complete_name
)))
437 _
=> CheckLintNameResult
::NoLint(None
),
442 /// Context for lint checking after type checking.
443 pub struct LateContext
<'tcx
> {
444 /// Type context we're checking in.
445 pub tcx
: TyCtxt
<'tcx
>,
447 /// Current body, or `None` if outside a body.
448 pub enclosing_body
: Option
<hir
::BodyId
>,
450 /// Type-checking results for the current body. Access using the `typeck_results`
451 /// and `maybe_typeck_results` methods, which handle querying the typeck results on demand.
452 // FIXME(eddyb) move all the code accessing internal fields like this,
453 // to this module, to avoid exposing it to lint logic.
454 pub(super) cached_typeck_results
: Cell
<Option
<&'tcx ty
::TypeckResults
<'tcx
>>>,
456 /// Parameter environment for the item we are in.
457 pub param_env
: ty
::ParamEnv
<'tcx
>,
459 /// Items accessible from the crate being checked.
460 pub access_levels
: &'tcx AccessLevels
,
462 /// The store of registered lints and the lint levels.
463 pub lint_store
: &'tcx LintStore
,
465 pub last_node_with_lint_attrs
: hir
::HirId
,
467 /// Generic type parameters in scope for the item we are in.
468 pub generics
: Option
<&'tcx hir
::Generics
<'tcx
>>,
470 /// We are only looking at one module
471 pub only_module
: bool
,
474 /// Context for lint checking of the AST, after expansion, before lowering to
476 pub struct EarlyContext
<'a
> {
477 /// Type context we're checking in.
478 pub sess
: &'a Session
,
480 /// The crate being checked.
481 pub krate
: &'a ast
::Crate
,
483 pub builder
: LintLevelsBuilder
<'a
>,
485 /// The store of registered lints and the lint levels.
486 pub lint_store
: &'a LintStore
,
488 pub buffered
: LintBuffer
,
491 pub trait LintPassObject
: Sized {}
493 impl LintPassObject
for EarlyLintPassObject {}
495 impl LintPassObject
for LateLintPassObject {}
497 pub trait LintContext
: Sized
{
498 type PassObject
: LintPassObject
;
500 fn sess(&self) -> &Session
;
501 fn lints(&self) -> &LintStore
;
503 fn lookup_with_diagnostics(
506 span
: Option
<impl Into
<MultiSpan
>>,
507 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
508 diagnostic
: BuiltinLintDiagnostics
,
510 self.lookup(lint
, span
, |lint
| {
511 // We first generate a blank diagnostic.
512 let mut db
= lint
.build("");
514 // Now, set up surrounding context.
515 let sess
= self.sess();
517 BuiltinLintDiagnostics
::Normal
=> (),
518 BuiltinLintDiagnostics
::BareTraitObject(span
, is_global
) => {
519 let (sugg
, app
) = match sess
.source_map().span_to_snippet(span
) {
520 Ok(s
) if is_global
=> {
521 (format
!("dyn ({})", s
), Applicability
::MachineApplicable
)
523 Ok(s
) => (format
!("dyn {}", s
), Applicability
::MachineApplicable
),
524 Err(_
) => ("dyn <type>".to_string(), Applicability
::HasPlaceholders
),
526 db
.span_suggestion(span
, "use `dyn`", sugg
, app
);
528 BuiltinLintDiagnostics
::AbsPathWithModule(span
) => {
529 let (sugg
, app
) = match sess
.source_map().span_to_snippet(span
) {
531 // FIXME(Manishearth) ideally the emitting code
532 // can tell us whether or not this is global
534 if s
.trim_start().starts_with("::") { "" }
else { "::" }
;
536 (format
!("crate{}{}", opt_colon
, s
), Applicability
::MachineApplicable
)
538 Err(_
) => ("crate::<path>".to_string(), Applicability
::HasPlaceholders
),
540 db
.span_suggestion(span
, "use `crate`", sugg
, app
);
542 BuiltinLintDiagnostics
::ProcMacroDeriveResolutionFallback(span
) => {
545 "names from parent modules are not accessible without an explicit import",
548 BuiltinLintDiagnostics
::MacroExpandedMacroExportsAccessedByAbsolutePaths(
551 db
.span_note(span_def
, "the macro is defined here");
553 BuiltinLintDiagnostics
::ElidedLifetimesInPaths(
560 add_elided_lifetime_in_path_suggestion(
570 BuiltinLintDiagnostics
::UnknownCrateTypes(span
, note
, sugg
) => {
571 db
.span_suggestion(span
, ¬e
, sugg
, Applicability
::MaybeIncorrect
);
573 BuiltinLintDiagnostics
::UnusedImports(message
, replaces
) => {
574 if !replaces
.is_empty() {
575 db
.tool_only_multipart_suggestion(
578 Applicability
::MachineApplicable
,
582 BuiltinLintDiagnostics
::RedundantImport(spans
, ident
) => {
583 for (span
, is_imported
) in spans
{
584 let introduced
= if is_imported { "imported" }
else { "defined" }
;
587 format
!("the item `{}` is already {} here", ident
, introduced
),
591 BuiltinLintDiagnostics
::DeprecatedMacro(suggestion
, span
) => {
592 stability
::deprecation_suggestion(&mut db
, "macro", suggestion
, span
)
594 BuiltinLintDiagnostics
::UnusedDocComment(span
) => {
595 db
.span_label(span
, "rustdoc does not generate documentation for macro invocations");
596 db
.help("to document an item produced by a macro, \
597 the macro must produce the documentation as part of its expansion");
600 // Rewrap `db`, and pass control to the user.
601 decorate(LintDiagnosticBuilder
::new(db
));
605 // FIXME: These methods should not take an Into<MultiSpan> -- instead, callers should need to
606 // set the span in their `decorate` function (preferably using set_span).
607 fn lookup
<S
: Into
<MultiSpan
>>(
611 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
614 fn struct_span_lint
<S
: Into
<MultiSpan
>>(
618 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
620 self.lookup(lint
, Some(span
), decorate
);
622 /// Emit a lint at the appropriate level, with no associated span.
623 fn lint(&self, lint
: &'
static Lint
, decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>)) {
624 self.lookup(lint
, None
as Option
<Span
>, decorate
);
628 impl<'a
> EarlyContext
<'a
> {
631 lint_store
: &'a LintStore
,
632 krate
: &'a ast
::Crate
,
633 buffered
: LintBuffer
,
634 warn_about_weird_lints
: bool
,
635 ) -> EarlyContext
<'a
> {
640 builder
: LintLevelsBuilder
::new(sess
, warn_about_weird_lints
, lint_store
),
646 impl LintContext
for LateContext
<'_
> {
647 type PassObject
= LateLintPassObject
;
649 /// Gets the overall compiler `Session` object.
650 fn sess(&self) -> &Session
{
654 fn lints(&self) -> &LintStore
{
658 fn lookup
<S
: Into
<MultiSpan
>>(
662 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
664 let hir_id
= self.last_node_with_lint_attrs
;
667 Some(s
) => self.tcx
.struct_span_lint_hir(lint
, hir_id
, s
, decorate
),
668 None
=> self.tcx
.struct_lint_node(lint
, hir_id
, decorate
),
673 impl LintContext
for EarlyContext
<'_
> {
674 type PassObject
= EarlyLintPassObject
;
676 /// Gets the overall compiler `Session` object.
677 fn sess(&self) -> &Session
{
681 fn lints(&self) -> &LintStore
{
685 fn lookup
<S
: Into
<MultiSpan
>>(
689 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
691 self.builder
.struct_lint(lint
, span
.map(|s
| s
.into()), decorate
)
695 impl<'tcx
> LateContext
<'tcx
> {
696 /// Gets the type-checking results for the current body,
697 /// or `None` if outside a body.
698 pub fn maybe_typeck_results(&self) -> Option
<&'tcx ty
::TypeckResults
<'tcx
>> {
699 self.cached_typeck_results
.get().or_else(|| {
700 self.enclosing_body
.map(|body
| {
701 let typeck_results
= self.tcx
.typeck_body(body
);
702 self.cached_typeck_results
.set(Some(typeck_results
));
708 /// Gets the type-checking results for the current body.
709 /// As this will ICE if called outside bodies, only call when working with
710 /// `Expr` or `Pat` nodes (they are guaranteed to be found only in bodies).
712 pub fn typeck_results(&self) -> &'tcx ty
::TypeckResults
<'tcx
> {
713 self.maybe_typeck_results().expect("`LateContext::typeck_results` called outside of body")
716 /// Returns the final resolution of a `QPath`, or `Res::Err` if unavailable.
717 /// Unlike `.typeck_results().qpath_res(qpath, id)`, this can be used even outside
718 /// bodies (e.g. for paths in `hir::Ty`), without any risk of ICE-ing.
719 pub fn qpath_res(&self, qpath
: &hir
::QPath
<'_
>, id
: hir
::HirId
) -> Res
{
721 hir
::QPath
::Resolved(_
, ref path
) => path
.res
,
722 hir
::QPath
::TypeRelative(..) | hir
::QPath
::LangItem(..) => self
723 .maybe_typeck_results()
724 .and_then(|typeck_results
| typeck_results
.type_dependent_def(id
))
725 .map_or(Res
::Err
, |(kind
, def_id
)| Res
::Def(kind
, def_id
)),
729 /// Check if a `DefId`'s path matches the given absolute type path usage.
731 /// Anonymous scopes such as `extern` imports are matched with `kw::Invalid`;
732 /// inherent `impl` blocks are matched with the name of the type.
734 /// Instead of using this method, it is often preferable to instead use
735 /// `rustc_diagnostic_item` or a `lang_item`. This is less prone to errors
736 /// as paths get invalidated if the target definition moves.
740 /// ```rust,ignore (no context or def id available)
741 /// if cx.match_def_path(def_id, &[sym::core, sym::option, sym::Option]) {
742 /// // The given `def_id` is that of an `Option` type
745 pub fn match_def_path(&self, def_id
: DefId
, path
: &[Symbol
]) -> bool
{
746 let names
= self.get_def_path(def_id
);
748 names
.len() == path
.len() && names
.into_iter().zip(path
.iter()).all(|(a
, &b
)| a
== b
)
751 /// Gets the absolute path of `def_id` as a vector of `Symbol`.
755 /// ```rust,ignore (no context or def id available)
756 /// let def_path = cx.get_def_path(def_id);
757 /// if let &[sym::core, sym::option, sym::Option] = &def_path[..] {
758 /// // The given `def_id` is that of an `Option` type
761 pub fn get_def_path(&self, def_id
: DefId
) -> Vec
<Symbol
> {
762 pub struct AbsolutePathPrinter
<'tcx
> {
763 pub tcx
: TyCtxt
<'tcx
>,
766 impl<'tcx
> Printer
<'tcx
> for AbsolutePathPrinter
<'tcx
> {
769 type Path
= Vec
<Symbol
>;
772 type DynExistential
= ();
775 fn tcx(&self) -> TyCtxt
<'tcx
> {
779 fn print_region(self, _region
: ty
::Region
<'_
>) -> Result
<Self::Region
, Self::Error
> {
783 fn print_type(self, _ty
: Ty
<'tcx
>) -> Result
<Self::Type
, Self::Error
> {
787 fn print_dyn_existential(
789 _predicates
: &'tcx ty
::List
<ty
::ExistentialPredicate
<'tcx
>>,
790 ) -> Result
<Self::DynExistential
, Self::Error
> {
794 fn print_const(self, _ct
: &'tcx ty
::Const
<'tcx
>) -> Result
<Self::Const
, Self::Error
> {
798 fn path_crate(self, cnum
: CrateNum
) -> Result
<Self::Path
, Self::Error
> {
799 Ok(vec
![self.tcx
.original_crate_name(cnum
)])
805 trait_ref
: Option
<ty
::TraitRef
<'tcx
>>,
806 ) -> Result
<Self::Path
, Self::Error
> {
807 if trait_ref
.is_none() {
808 if let ty
::Adt(def
, substs
) = self_ty
.kind() {
809 return self.print_def_path(def
.did
, substs
);
813 // This shouldn't ever be needed, but just in case:
814 with_no_trimmed_paths(|| {
815 Ok(vec
![match trait_ref
{
816 Some(trait_ref
) => Symbol
::intern(&format
!("{:?}", trait_ref
)),
817 None
=> Symbol
::intern(&format
!("<{}>", self_ty
)),
824 print_prefix
: impl FnOnce(Self) -> Result
<Self::Path
, Self::Error
>,
825 _disambiguated_data
: &DisambiguatedDefPathData
,
827 trait_ref
: Option
<ty
::TraitRef
<'tcx
>>,
828 ) -> Result
<Self::Path
, Self::Error
> {
829 let mut path
= print_prefix(self)?
;
831 // This shouldn't ever be needed, but just in case:
832 path
.push(match trait_ref
{
833 Some(trait_ref
) => with_no_trimmed_paths(|| {
834 Symbol
::intern(&format
!(
836 trait_ref
.print_only_trait_path(),
841 with_no_trimmed_paths(|| Symbol
::intern(&format
!("<impl {}>", self_ty
)))
850 print_prefix
: impl FnOnce(Self) -> Result
<Self::Path
, Self::Error
>,
851 disambiguated_data
: &DisambiguatedDefPathData
,
852 ) -> Result
<Self::Path
, Self::Error
> {
853 let mut path
= print_prefix(self)?
;
855 // Skip `::{{constructor}}` on tuple/unit structs.
856 if let DefPathData
::Ctor
= disambiguated_data
.data
{
860 path
.push(Symbol
::intern(&disambiguated_data
.data
.to_string()));
864 fn path_generic_args(
866 print_prefix
: impl FnOnce(Self) -> Result
<Self::Path
, Self::Error
>,
867 _args
: &[GenericArg
<'tcx
>],
868 ) -> Result
<Self::Path
, Self::Error
> {
873 AbsolutePathPrinter { tcx: self.tcx }
.print_def_path(def_id
, &[]).unwrap()
877 impl<'tcx
> LayoutOf
for LateContext
<'tcx
> {
879 type TyAndLayout
= Result
<TyAndLayout
<'tcx
>, LayoutError
<'tcx
>>;
881 fn layout_of(&self, ty
: Ty
<'tcx
>) -> Self::TyAndLayout
{
882 self.tcx
.layout_of(self.param_env
.and(ty
))