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
::{is_known_lint_tool, 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
::{self, LayoutOf}
;
51 /// Information about the registered lints.
53 /// This is basically the subset of `Context` that we can
54 /// build early in the compile pipeline.
55 pub struct LintStore
{
57 lints
: Vec
<&'
static Lint
>,
59 /// Constructor functions for each variety of lint pass.
61 /// These should only be called once, but since we want to avoid locks or
62 /// interior mutability, we don't enforce this (and lints should, in theory,
63 /// be compatible with being constructed more than once, though not
64 /// necessarily in a sane manner. This is safe though.)
65 pub pre_expansion_passes
: Vec
<Box
<dyn Fn() -> EarlyLintPassObject
+ sync
::Send
+ sync
::Sync
>>,
66 pub early_passes
: Vec
<Box
<dyn Fn() -> EarlyLintPassObject
+ sync
::Send
+ sync
::Sync
>>,
67 pub late_passes
: Vec
<Box
<dyn Fn() -> LateLintPassObject
+ sync
::Send
+ sync
::Sync
>>,
68 /// This is unique in that we construct them per-module, so not once.
69 pub late_module_passes
: Vec
<Box
<dyn Fn() -> LateLintPassObject
+ sync
::Send
+ sync
::Sync
>>,
71 /// Lints indexed by name.
72 by_name
: FxHashMap
<String
, TargetLint
>,
74 /// Map of registered lint groups to what lints they expand to.
75 lint_groups
: FxHashMap
<&'
static str, LintGroup
>,
78 impl SessionLintStore
for LintStore
{
79 fn name_to_lint(&self, lint_name
: &str) -> LintId
{
81 .find_lints(lint_name
)
82 .unwrap_or_else(|_
| panic
!("Failed to find lint with name `{}`", lint_name
));
84 if let &[lint
] = lints
.as_slice() {
87 panic
!("Found mutliple lints with name `{}`: {:?}", lint_name
, lints
);
92 /// The target of the `by_name` map, which accounts for renaming/deprecation.
95 /// A direct lint target
98 /// Temporary renaming, used for easing migration pain; see #16545
99 Renamed(String
, LintId
),
101 /// Lint with this name existed previously, but has been removed/deprecated.
102 /// The string argument is the reason for removal.
105 /// A lint name that should give no warnings and have no effect.
107 /// This is used by rustc to avoid warning about old rustdoc lints before rustdoc registers them as tool lints.
111 pub enum FindLintError
{
118 /// Whether deprecation warnings should be suppressed for this alias.
123 lint_ids
: Vec
<LintId
>,
125 depr
: Option
<LintAlias
>,
128 pub enum CheckLintNameResult
<'a
> {
130 /// Lint doesn't exist. Potentially contains a suggestion for a correct lint name.
131 NoLint(Option
<Symbol
>),
132 /// The lint refers to a tool that has not been registered.
134 /// The lint is either renamed or removed. This is the warning
135 /// message, and an optional new name (`None` if removed).
136 Warning(String
, Option
<String
>),
137 /// The lint is from a tool. If the Option is None, then either
138 /// the lint does not exist in the tool or the code was not
139 /// compiled with the tool and therefore the lint was never
140 /// added to the `LintStore`. Otherwise the `LintId` will be
141 /// returned as if it where a rustc lint.
142 Tool(Result
<&'a
[LintId
], (Option
<&'a
[LintId
]>, String
)>),
146 pub fn new() -> LintStore
{
149 pre_expansion_passes
: vec
![],
150 early_passes
: vec
![],
152 late_module_passes
: vec
![],
153 by_name
: Default
::default(),
154 lint_groups
: Default
::default(),
158 pub fn get_lints
<'t
>(&'t
self) -> &'t
[&'
static Lint
] {
162 pub fn get_lint_groups
<'t
>(&'t
self) -> Vec
<(&'
static str, Vec
<LintId
>, bool
)> {
165 .filter(|(_
, LintGroup { depr, .. }
)| {
166 // Don't display deprecated lint groups.
169 .map(|(k
, LintGroup { lint_ids, from_plugin, .. }
)| {
170 (*k
, lint_ids
.clone(), *from_plugin
)
175 pub fn register_early_pass(
177 pass
: impl Fn() -> EarlyLintPassObject
+ '
static + sync
::Send
+ sync
::Sync
,
179 self.early_passes
.push(Box
::new(pass
));
183 pub fn register_pre_expansion_pass(
185 pass
: impl Fn() -> EarlyLintPassObject
+ '
static + sync
::Send
+ sync
::Sync
,
187 self.pre_expansion_passes
.push(Box
::new(pass
));
190 pub fn register_late_pass(
192 pass
: impl Fn() -> LateLintPassObject
+ '
static + sync
::Send
+ sync
::Sync
,
194 self.late_passes
.push(Box
::new(pass
));
197 pub fn register_late_mod_pass(
199 pass
: impl Fn() -> LateLintPassObject
+ '
static + sync
::Send
+ sync
::Sync
,
201 self.late_module_passes
.push(Box
::new(pass
));
204 // Helper method for register_early/late_pass
205 pub fn register_lints(&mut self, lints
: &[&'
static Lint
]) {
207 self.lints
.push(lint
);
209 let id
= LintId
::of(lint
);
210 if self.by_name
.insert(lint
.name_lower(), Id(id
)).is_some() {
211 bug
!("duplicate specification of lint {}", lint
.name_lower())
214 if let Some(FutureIncompatibleInfo { reason, .. }
) = lint
.future_incompatible
{
215 if let Some(edition
) = reason
.edition() {
217 .entry(edition
.lint_name())
218 .or_insert(LintGroup
{
220 from_plugin
: lint
.is_plugin
,
226 // Lints belonging to the `future_incompatible` lint group are lints where a
227 // future version of rustc will cause existing code to stop compiling.
228 // Lints tied to an edition don't count because they are opt-in.
230 .entry("future_incompatible")
231 .or_insert(LintGroup
{
233 from_plugin
: lint
.is_plugin
,
243 pub fn register_group_alias(&mut self, lint_name
: &'
static str, alias
: &'
static str) {
244 self.lint_groups
.insert(
249 depr
: Some(LintAlias { name: lint_name, silent: true }
),
254 pub fn register_group(
258 deprecated_name
: Option
<&'
static str>,
263 .insert(name
, LintGroup { lint_ids: to, from_plugin, depr: None }
)
265 if let Some(deprecated
) = deprecated_name
{
266 self.lint_groups
.insert(
271 depr
: Some(LintAlias { name, silent: false }
),
277 bug
!("duplicate specification of lint group {}", name
);
281 /// This lint should give no warning and have no effect.
283 /// This is used by rustc to avoid warning about old rustdoc lints before rustdoc registers them as tool lints.
285 pub fn register_ignored(&mut self, name
: &str) {
286 if self.by_name
.insert(name
.to_string(), Ignored
).is_some() {
287 bug
!("duplicate specification of lint {}", name
);
291 /// This lint has been renamed; warn about using the new name and apply the lint.
293 pub fn register_renamed(&mut self, old_name
: &str, new_name
: &str) {
294 let target
= match self.by_name
.get(new_name
) {
295 Some(&Id(lint_id
)) => lint_id
,
296 _
=> bug
!("invalid lint renaming of {} to {}", old_name
, new_name
),
298 self.by_name
.insert(old_name
.to_string(), Renamed(new_name
.to_string(), target
));
301 pub fn register_removed(&mut self, name
: &str, reason
: &str) {
302 self.by_name
.insert(name
.into(), Removed(reason
.into()));
305 pub fn find_lints(&self, mut lint_name
: &str) -> Result
<Vec
<LintId
>, FindLintError
> {
306 match self.by_name
.get(lint_name
) {
307 Some(&Id(lint_id
)) => Ok(vec
![lint_id
]),
308 Some(&Renamed(_
, lint_id
)) => Ok(vec
![lint_id
]),
309 Some(&Removed(_
)) => Err(FindLintError
::Removed
),
310 Some(&Ignored
) => Ok(vec
![]),
312 return match self.lint_groups
.get(lint_name
) {
313 Some(LintGroup { lint_ids, depr, .. }
) => {
314 if let Some(LintAlias { name, .. }
) = depr
{
320 None
=> Err(FindLintError
::Removed
),
326 /// Checks the validity of lint names derived from the command line.
327 pub fn check_lint_name_cmdline(
332 crate_attrs
: &[ast
::Attribute
],
334 let (tool_name
, lint_name_only
) = parse_lint_and_tool_name(lint_name
);
335 if lint_name_only
== crate::WARNINGS
.name_lower() && level
== Level
::ForceWarn
{
336 return struct_span_err
!(
340 "`{}` lint group is not supported with ´--force-warn´",
341 crate::WARNINGS
.name_lower()
345 let db
= match self.check_lint_name(sess
, lint_name_only
, tool_name
, crate_attrs
) {
346 CheckLintNameResult
::Ok(_
) => None
,
347 CheckLintNameResult
::Warning(ref msg
, _
) => Some(sess
.struct_warn(msg
)),
348 CheckLintNameResult
::NoLint(suggestion
) => {
350 struct_span_err
!(sess
, DUMMY_SP
, E0602
, "unknown lint: `{}`", lint_name
);
352 if let Some(suggestion
) = suggestion
{
353 err
.help(&format
!("did you mean: `{}`", suggestion
));
358 CheckLintNameResult
::Tool(result
) => match result
{
359 Err((Some(_
), new_name
)) => Some(sess
.struct_warn(&format
!(
360 "lint name `{}` is deprecated \
361 and does not have an effect anymore. \
367 CheckLintNameResult
::NoTool
=> Some(struct_span_err
!(
371 "unknown lint tool: `{}`",
376 if let Some(mut db
) = db
{
378 "requested on the command line with `{} {}`",
380 Level
::Allow
=> "-A",
382 Level
::ForceWarn
=> "--force-warn",
384 Level
::Forbid
=> "-F",
393 /// True if this symbol represents a lint group name.
394 pub fn is_lint_group(&self, lint_name
: Symbol
) -> bool
{
396 "is_lint_group(lint_name={:?}, lint_groups={:?})",
398 self.lint_groups
.keys().collect
::<Vec
<_
>>()
400 let lint_name_str
= &*lint_name
.as_str();
401 self.lint_groups
.contains_key(&lint_name_str
) || {
402 let warnings_name_str
= crate::WARNINGS
.name_lower();
403 lint_name_str
== &*warnings_name_str
407 /// Checks the name of a lint for its existence, and whether it was
408 /// renamed or removed. Generates a DiagnosticBuilder containing a
409 /// warning for renamed and removed lints. This is over both lint
410 /// names from attributes and those passed on the command line. Since
411 /// it emits non-fatal warnings and there are *two* lint passes that
412 /// inspect attributes, this is only run from the late pass to avoid
413 /// printing duplicate warnings.
414 pub fn check_lint_name(
418 tool_name
: Option
<Symbol
>,
419 crate_attrs
: &[ast
::Attribute
],
420 ) -> CheckLintNameResult
<'_
> {
421 if let Some(tool_name
) = tool_name
{
422 if !is_known_lint_tool(tool_name
, sess
, crate_attrs
) {
423 return CheckLintNameResult
::NoTool
;
427 let complete_name
= if let Some(tool_name
) = tool_name
{
428 format
!("{}::{}", tool_name
, lint_name
)
430 lint_name
.to_string()
432 // If the lint was scoped with `tool::` check if the tool lint exists
433 if let Some(tool_name
) = tool_name
{
434 match self.by_name
.get(&complete_name
) {
435 None
=> match self.lint_groups
.get(&*complete_name
) {
436 // If the lint isn't registered, there are two possibilities:
438 // 1. The tool is currently running, so this lint really doesn't exist.
439 // FIXME: should this handle tools that never register a lint, like rustfmt?
440 tracing
::debug
!("lints={:?}", self.by_name
.keys().collect
::<Vec
<_
>>());
441 let tool_prefix
= format
!("{}::", tool_name
);
442 return if self.by_name
.keys().any(|lint
| lint
.starts_with(&tool_prefix
)) {
443 self.no_lint_suggestion(&complete_name
)
445 // 2. The tool isn't currently running, so no lints will be registered.
446 // To avoid giving a false positive, ignore all unknown lints.
447 CheckLintNameResult
::Tool(Err((None
, String
::new())))
450 Some(LintGroup { lint_ids, .. }
) => {
451 return CheckLintNameResult
::Tool(Ok(&lint_ids
));
454 Some(&Id(ref id
)) => return CheckLintNameResult
::Tool(Ok(slice
::from_ref(id
))),
455 // If the lint was registered as removed or renamed by the lint tool, we don't need
456 // to treat tool_lints and rustc lints different and can use the code below.
460 match self.by_name
.get(&complete_name
) {
461 Some(&Renamed(ref new_name
, _
)) => CheckLintNameResult
::Warning(
462 format
!("lint `{}` has been renamed to `{}`", complete_name
, new_name
),
463 Some(new_name
.to_owned()),
465 Some(&Removed(ref reason
)) => CheckLintNameResult
::Warning(
466 format
!("lint `{}` has been removed: {}", complete_name
, reason
),
469 None
=> match self.lint_groups
.get(&*complete_name
) {
470 // If neither the lint, nor the lint group exists check if there is a `clippy::`
471 // variant of this lint
472 None
=> self.check_tool_name_for_backwards_compat(&complete_name
, "clippy"),
473 Some(LintGroup { lint_ids, depr, .. }
) => {
474 // Check if the lint group name is deprecated
475 if let Some(LintAlias { name, silent }
) = depr
{
476 let LintGroup { lint_ids, .. }
= self.lint_groups
.get(name
).unwrap();
478 CheckLintNameResult
::Ok(&lint_ids
)
480 CheckLintNameResult
::Tool(Err((Some(&lint_ids
), (*name
).to_string())))
483 CheckLintNameResult
::Ok(&lint_ids
)
486 Some(&Id(ref id
)) => CheckLintNameResult
::Ok(slice
::from_ref(id
)),
487 Some(&Ignored
) => CheckLintNameResult
::Ok(&[]),
491 fn no_lint_suggestion(&self, lint_name
: &str) -> CheckLintNameResult
<'_
> {
492 let name_lower
= lint_name
.to_lowercase();
494 if lint_name
.chars().any(char::is_uppercase
) && self.find_lints(&name_lower
).is_ok() {
495 // First check if the lint name is (partly) in upper case instead of lower case...
496 return CheckLintNameResult
::NoLint(Some(Symbol
::intern(&name_lower
)));
498 // ...if not, search for lints with a similar name
499 let groups
= self.lint_groups
.keys().copied().map(Symbol
::intern
);
500 let lints
= self.lints
.iter().map(|l
| Symbol
::intern(&l
.name_lower()));
501 let names
: Vec
<Symbol
> = groups
.chain(lints
).collect();
502 let suggestion
= find_best_match_for_name(&names
, Symbol
::intern(&name_lower
), None
);
503 CheckLintNameResult
::NoLint(suggestion
)
506 fn check_tool_name_for_backwards_compat(
510 ) -> CheckLintNameResult
<'_
> {
511 let complete_name
= format
!("{}::{}", tool_name
, lint_name
);
512 match self.by_name
.get(&complete_name
) {
513 None
=> match self.lint_groups
.get(&*complete_name
) {
514 // Now we are sure, that this lint exists nowhere
515 None
=> self.no_lint_suggestion(lint_name
),
516 Some(LintGroup { lint_ids, depr, .. }
) => {
517 // Reaching this would be weird, but let's cover this case anyway
518 if let Some(LintAlias { name, silent }
) = depr
{
519 let LintGroup { lint_ids, .. }
= self.lint_groups
.get(name
).unwrap();
521 CheckLintNameResult
::Tool(Err((Some(&lint_ids
), complete_name
)))
523 CheckLintNameResult
::Tool(Err((Some(&lint_ids
), (*name
).to_string())))
526 CheckLintNameResult
::Tool(Err((Some(&lint_ids
), complete_name
)))
529 Some(&Id(ref id
)) => {
530 CheckLintNameResult
::Tool(Err((Some(slice
::from_ref(id
)), complete_name
)))
533 tracing
::debug
!("got renamed lint {:?}", other
);
534 CheckLintNameResult
::NoLint(None
)
540 /// Context for lint checking after type checking.
541 pub struct LateContext
<'tcx
> {
542 /// Type context we're checking in.
543 pub tcx
: TyCtxt
<'tcx
>,
545 /// Current body, or `None` if outside a body.
546 pub enclosing_body
: Option
<hir
::BodyId
>,
548 /// Type-checking results for the current body. Access using the `typeck_results`
549 /// and `maybe_typeck_results` methods, which handle querying the typeck results on demand.
550 // FIXME(eddyb) move all the code accessing internal fields like this,
551 // to this module, to avoid exposing it to lint logic.
552 pub(super) cached_typeck_results
: Cell
<Option
<&'tcx ty
::TypeckResults
<'tcx
>>>,
554 /// Parameter environment for the item we are in.
555 pub param_env
: ty
::ParamEnv
<'tcx
>,
557 /// Items accessible from the crate being checked.
558 pub access_levels
: &'tcx AccessLevels
,
560 /// The store of registered lints and the lint levels.
561 pub lint_store
: &'tcx LintStore
,
563 pub last_node_with_lint_attrs
: hir
::HirId
,
565 /// Generic type parameters in scope for the item we are in.
566 pub generics
: Option
<&'tcx hir
::Generics
<'tcx
>>,
568 /// We are only looking at one module
569 pub only_module
: bool
,
572 /// Context for lint checking of the AST, after expansion, before lowering to
574 pub struct EarlyContext
<'a
> {
575 /// Type context we're checking in.
576 pub sess
: &'a Session
,
578 /// The crate being checked.
579 pub krate
: &'a ast
::Crate
,
581 pub builder
: LintLevelsBuilder
<'a
>,
583 /// The store of registered lints and the lint levels.
584 pub lint_store
: &'a LintStore
,
586 pub buffered
: LintBuffer
,
589 pub trait LintPassObject
: Sized {}
591 impl LintPassObject
for EarlyLintPassObject {}
593 impl LintPassObject
for LateLintPassObject {}
595 pub trait LintContext
: Sized
{
596 type PassObject
: LintPassObject
;
598 fn sess(&self) -> &Session
;
599 fn lints(&self) -> &LintStore
;
601 fn lookup_with_diagnostics(
604 span
: Option
<impl Into
<MultiSpan
>>,
605 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
606 diagnostic
: BuiltinLintDiagnostics
,
608 self.lookup(lint
, span
, |lint
| {
609 // We first generate a blank diagnostic.
610 let mut db
= lint
.build("");
612 // Now, set up surrounding context.
613 let sess
= self.sess();
615 BuiltinLintDiagnostics
::Normal
=> (),
616 BuiltinLintDiagnostics
::BareTraitObject(span
, is_global
) => {
617 let (sugg
, app
) = match sess
.source_map().span_to_snippet(span
) {
618 Ok(s
) if is_global
=> {
619 (format
!("dyn ({})", s
), Applicability
::MachineApplicable
)
621 Ok(s
) => (format
!("dyn {}", s
), Applicability
::MachineApplicable
),
622 Err(_
) => ("dyn <type>".to_string(), Applicability
::HasPlaceholders
),
624 db
.span_suggestion(span
, "use `dyn`", sugg
, app
);
626 BuiltinLintDiagnostics
::AbsPathWithModule(span
) => {
627 let (sugg
, app
) = match sess
.source_map().span_to_snippet(span
) {
629 // FIXME(Manishearth) ideally the emitting code
630 // can tell us whether or not this is global
632 if s
.trim_start().starts_with("::") { "" }
else { "::" }
;
634 (format
!("crate{}{}", opt_colon
, s
), Applicability
::MachineApplicable
)
636 Err(_
) => ("crate::<path>".to_string(), Applicability
::HasPlaceholders
),
638 db
.span_suggestion(span
, "use `crate`", sugg
, app
);
640 BuiltinLintDiagnostics
::ProcMacroDeriveResolutionFallback(span
) => {
643 "names from parent modules are not accessible without an explicit import",
646 BuiltinLintDiagnostics
::MacroExpandedMacroExportsAccessedByAbsolutePaths(
649 db
.span_note(span_def
, "the macro is defined here");
651 BuiltinLintDiagnostics
::ElidedLifetimesInPaths(
658 add_elided_lifetime_in_path_suggestion(
668 BuiltinLintDiagnostics
::UnknownCrateTypes(span
, note
, sugg
) => {
669 db
.span_suggestion(span
, ¬e
, sugg
, Applicability
::MaybeIncorrect
);
671 BuiltinLintDiagnostics
::UnusedImports(message
, replaces
) => {
672 if !replaces
.is_empty() {
673 db
.tool_only_multipart_suggestion(
676 Applicability
::MachineApplicable
,
680 BuiltinLintDiagnostics
::RedundantImport(spans
, ident
) => {
681 for (span
, is_imported
) in spans
{
682 let introduced
= if is_imported { "imported" }
else { "defined" }
;
685 format
!("the item `{}` is already {} here", ident
, introduced
),
689 BuiltinLintDiagnostics
::DeprecatedMacro(suggestion
, span
) => {
690 stability
::deprecation_suggestion(&mut db
, "macro", suggestion
, span
)
692 BuiltinLintDiagnostics
::UnusedDocComment(span
) => {
693 db
.span_label(span
, "rustdoc does not generate documentation for macro invocations");
694 db
.help("to document an item produced by a macro, \
695 the macro must produce the documentation as part of its expansion");
697 BuiltinLintDiagnostics
::PatternsInFnsWithoutBody(span
, ident
) => {
698 db
.span_suggestion(span
, "remove `mut` from the parameter", ident
.to_string(), Applicability
::MachineApplicable
);
700 BuiltinLintDiagnostics
::MissingAbi(span
, default_abi
) => {
701 db
.span_label(span
, "ABI should be specified here");
702 db
.help(&format
!("the default ABI is {}", default_abi
.name()));
704 BuiltinLintDiagnostics
::LegacyDeriveHelpers(span
) => {
705 db
.span_label(span
, "the attribute is introduced here");
707 BuiltinLintDiagnostics
::ExternDepSpec(krate
, loc
) => {
708 let json
= match loc
{
709 ExternDepSpec
::Json(json
) => {
710 db
.help(&format
!("remove unnecessary dependency `{}`", krate
));
713 ExternDepSpec
::Raw(raw
) => {
714 db
.help(&format
!("remove unnecessary dependency `{}` at `{}`", krate
, raw
));
715 db
.span_suggestion_with_style(
717 "raw extern location",
719 Applicability
::Unspecified
,
720 SuggestionStyle
::CompletelyHidden
,
725 db
.tool_only_suggestion_with_metadata(
726 "json extern location",
727 Applicability
::Unspecified
,
731 BuiltinLintDiagnostics
::ProcMacroBackCompat(note
) => {
734 BuiltinLintDiagnostics
::OrPatternsBackCompat(span
,suggestion
) => {
735 db
.span_suggestion(span
, "use pat_param to preserve semantics", suggestion
, Applicability
::MachineApplicable
);
737 BuiltinLintDiagnostics
::ReservedPrefix(span
) => {
738 db
.span_label(span
, "unknown prefix");
739 db
.span_suggestion_verbose(
741 "insert whitespace here to avoid this being parsed as a prefix in Rust 2021",
743 Applicability
::MachineApplicable
,
746 BuiltinLintDiagnostics
::UnusedBuiltinAttribute
{
753 &format
!("the built-in attribute `{attr_name}` will be ignored, since it's applied to the macro invocation `{macro_name}`")
756 BuiltinLintDiagnostics
::TrailingMacro(is_trailing
, name
) => {
758 db
.note("macro invocations at the end of a block are treated as expressions");
759 db
.note(&format
!("to ignore the value produced by the macro, add a semicolon after the invocation of `{name}`"));
762 BuiltinLintDiagnostics
::BreakWithLabelAndLoop(span
) => {
763 db
.multipart_suggestion(
764 "wrap this expression in parentheses",
765 vec
![(span
.shrink_to_lo(), "(".to_string()),
766 (span
.shrink_to_hi(), ")".to_string())],
767 Applicability
::MachineApplicable
770 BuiltinLintDiagnostics
::NamedAsmLabel(help
) => {
772 db
.note("see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information");
775 // Rewrap `db`, and pass control to the user.
776 decorate(LintDiagnosticBuilder
::new(db
));
780 // FIXME: These methods should not take an Into<MultiSpan> -- instead, callers should need to
781 // set the span in their `decorate` function (preferably using set_span).
782 fn lookup
<S
: Into
<MultiSpan
>>(
786 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
789 fn struct_span_lint
<S
: Into
<MultiSpan
>>(
793 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
795 self.lookup(lint
, Some(span
), decorate
);
797 /// Emit a lint at the appropriate level, with no associated span.
798 fn lint(&self, lint
: &'
static Lint
, decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>)) {
799 self.lookup(lint
, None
as Option
<Span
>, decorate
);
803 impl<'a
> EarlyContext
<'a
> {
806 lint_store
: &'a LintStore
,
807 krate
: &'a ast
::Crate
,
808 buffered
: LintBuffer
,
809 warn_about_weird_lints
: bool
,
810 ) -> EarlyContext
<'a
> {
815 builder
: LintLevelsBuilder
::new(sess
, warn_about_weird_lints
, lint_store
, &krate
.attrs
),
821 impl LintContext
for LateContext
<'_
> {
822 type PassObject
= LateLintPassObject
;
824 /// Gets the overall compiler `Session` object.
825 fn sess(&self) -> &Session
{
829 fn lints(&self) -> &LintStore
{
833 fn lookup
<S
: Into
<MultiSpan
>>(
837 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
839 let hir_id
= self.last_node_with_lint_attrs
;
842 Some(s
) => self.tcx
.struct_span_lint_hir(lint
, hir_id
, s
, decorate
),
843 None
=> self.tcx
.struct_lint_node(lint
, hir_id
, decorate
),
848 impl LintContext
for EarlyContext
<'_
> {
849 type PassObject
= EarlyLintPassObject
;
851 /// Gets the overall compiler `Session` object.
852 fn sess(&self) -> &Session
{
856 fn lints(&self) -> &LintStore
{
860 fn lookup
<S
: Into
<MultiSpan
>>(
864 decorate
: impl for<'a
> FnOnce(LintDiagnosticBuilder
<'a
>),
866 self.builder
.struct_lint(lint
, span
.map(|s
| s
.into()), decorate
)
870 impl<'tcx
> LateContext
<'tcx
> {
871 /// Gets the type-checking results for the current body,
872 /// or `None` if outside a body.
873 pub fn maybe_typeck_results(&self) -> Option
<&'tcx ty
::TypeckResults
<'tcx
>> {
874 self.cached_typeck_results
.get().or_else(|| {
875 self.enclosing_body
.map(|body
| {
876 let typeck_results
= self.tcx
.typeck_body(body
);
877 self.cached_typeck_results
.set(Some(typeck_results
));
883 /// Gets the type-checking results for the current body.
884 /// As this will ICE if called outside bodies, only call when working with
885 /// `Expr` or `Pat` nodes (they are guaranteed to be found only in bodies).
887 pub fn typeck_results(&self) -> &'tcx ty
::TypeckResults
<'tcx
> {
888 self.maybe_typeck_results().expect("`LateContext::typeck_results` called outside of body")
891 /// Returns the final resolution of a `QPath`, or `Res::Err` if unavailable.
892 /// Unlike `.typeck_results().qpath_res(qpath, id)`, this can be used even outside
893 /// bodies (e.g. for paths in `hir::Ty`), without any risk of ICE-ing.
894 pub fn qpath_res(&self, qpath
: &hir
::QPath
<'_
>, id
: hir
::HirId
) -> Res
{
896 hir
::QPath
::Resolved(_
, ref path
) => path
.res
,
897 hir
::QPath
::TypeRelative(..) | hir
::QPath
::LangItem(..) => self
898 .maybe_typeck_results()
899 .filter(|typeck_results
| typeck_results
.hir_owner
== id
.owner
)
901 if self.tcx
.has_typeck_results(id
.owner
.to_def_id()) {
902 Some(self.tcx
.typeck(id
.owner
))
907 .and_then(|typeck_results
| typeck_results
.type_dependent_def(id
))
908 .map_or(Res
::Err
, |(kind
, def_id
)| Res
::Def(kind
, def_id
)),
912 /// Check if a `DefId`'s path matches the given absolute type path usage.
914 /// Anonymous scopes such as `extern` imports are matched with `kw::Empty`;
915 /// inherent `impl` blocks are matched with the name of the type.
917 /// Instead of using this method, it is often preferable to instead use
918 /// `rustc_diagnostic_item` or a `lang_item`. This is less prone to errors
919 /// as paths get invalidated if the target definition moves.
923 /// ```rust,ignore (no context or def id available)
924 /// if cx.match_def_path(def_id, &[sym::core, sym::option, sym::Option]) {
925 /// // The given `def_id` is that of an `Option` type
929 /// Used by clippy, but should be replaced by diagnostic items eventually.
930 pub fn match_def_path(&self, def_id
: DefId
, path
: &[Symbol
]) -> bool
{
931 let names
= self.get_def_path(def_id
);
933 names
.len() == path
.len() && iter
::zip(names
, path
).all(|(a
, &b
)| a
== b
)
936 /// Gets the absolute path of `def_id` as a vector of `Symbol`.
940 /// ```rust,ignore (no context or def id available)
941 /// let def_path = cx.get_def_path(def_id);
942 /// if let &[sym::core, sym::option, sym::Option] = &def_path[..] {
943 /// // The given `def_id` is that of an `Option` type
946 pub fn get_def_path(&self, def_id
: DefId
) -> Vec
<Symbol
> {
947 pub struct AbsolutePathPrinter
<'tcx
> {
948 pub tcx
: TyCtxt
<'tcx
>,
951 impl<'tcx
> Printer
<'tcx
> for AbsolutePathPrinter
<'tcx
> {
954 type Path
= Vec
<Symbol
>;
957 type DynExistential
= ();
960 fn tcx(&self) -> TyCtxt
<'tcx
> {
964 fn print_region(self, _region
: ty
::Region
<'_
>) -> Result
<Self::Region
, Self::Error
> {
968 fn print_type(self, _ty
: Ty
<'tcx
>) -> Result
<Self::Type
, Self::Error
> {
972 fn print_dyn_existential(
974 _predicates
: &'tcx ty
::List
<ty
::Binder
<'tcx
, ty
::ExistentialPredicate
<'tcx
>>>,
975 ) -> Result
<Self::DynExistential
, Self::Error
> {
979 fn print_const(self, _ct
: &'tcx ty
::Const
<'tcx
>) -> Result
<Self::Const
, Self::Error
> {
983 fn path_crate(self, cnum
: CrateNum
) -> Result
<Self::Path
, Self::Error
> {
984 Ok(vec
![self.tcx
.crate_name(cnum
)])
990 trait_ref
: Option
<ty
::TraitRef
<'tcx
>>,
991 ) -> Result
<Self::Path
, Self::Error
> {
992 if trait_ref
.is_none() {
993 if let ty
::Adt(def
, substs
) = self_ty
.kind() {
994 return self.print_def_path(def
.did
, substs
);
998 // This shouldn't ever be needed, but just in case:
999 with_no_trimmed_paths(|| {
1000 Ok(vec
![match trait_ref
{
1001 Some(trait_ref
) => Symbol
::intern(&format
!("{:?}", trait_ref
)),
1002 None
=> Symbol
::intern(&format
!("<{}>", self_ty
)),
1007 fn path_append_impl(
1009 print_prefix
: impl FnOnce(Self) -> Result
<Self::Path
, Self::Error
>,
1010 _disambiguated_data
: &DisambiguatedDefPathData
,
1012 trait_ref
: Option
<ty
::TraitRef
<'tcx
>>,
1013 ) -> Result
<Self::Path
, Self::Error
> {
1014 let mut path
= print_prefix(self)?
;
1016 // This shouldn't ever be needed, but just in case:
1017 path
.push(match trait_ref
{
1018 Some(trait_ref
) => with_no_trimmed_paths(|| {
1019 Symbol
::intern(&format
!(
1021 trait_ref
.print_only_trait_path(),
1026 with_no_trimmed_paths(|| Symbol
::intern(&format
!("<impl {}>", self_ty
)))
1035 print_prefix
: impl FnOnce(Self) -> Result
<Self::Path
, Self::Error
>,
1036 disambiguated_data
: &DisambiguatedDefPathData
,
1037 ) -> Result
<Self::Path
, Self::Error
> {
1038 let mut path
= print_prefix(self)?
;
1040 // Skip `::{{constructor}}` on tuple/unit structs.
1041 if let DefPathData
::Ctor
= disambiguated_data
.data
{
1045 path
.push(Symbol
::intern(&disambiguated_data
.data
.to_string()));
1049 fn path_generic_args(
1051 print_prefix
: impl FnOnce(Self) -> Result
<Self::Path
, Self::Error
>,
1052 _args
: &[GenericArg
<'tcx
>],
1053 ) -> Result
<Self::Path
, Self::Error
> {
1058 AbsolutePathPrinter { tcx: self.tcx }
.print_def_path(def_id
, &[]).unwrap()
1062 impl<'tcx
> abi
::HasDataLayout
for LateContext
<'tcx
> {
1064 fn data_layout(&self) -> &abi
::TargetDataLayout
{
1065 &self.tcx
.data_layout
1069 impl<'tcx
> ty
::layout
::HasTyCtxt
<'tcx
> for LateContext
<'tcx
> {
1071 fn tcx(&self) -> TyCtxt
<'tcx
> {
1076 impl<'tcx
> ty
::layout
::HasParamEnv
<'tcx
> for LateContext
<'tcx
> {
1078 fn param_env(&self) -> ty
::ParamEnv
<'tcx
> {
1083 impl<'tcx
> LayoutOf
<'tcx
> for LateContext
<'tcx
> {
1085 type TyAndLayout
= Result
<TyAndLayout
<'tcx
>, LayoutError
<'tcx
>>;
1087 fn layout_of(&self, ty
: Ty
<'tcx
>) -> Self::TyAndLayout
{
1088 self.tcx
.layout_of(self.param_env
.and(ty
))
1092 pub fn parse_lint_and_tool_name(lint_name
: &str) -> (Option
<Symbol
>, &str) {
1093 match lint_name
.split_once("::") {
1094 Some((tool_name
, lint_name
)) => {
1095 let tool_name
= Symbol
::intern(tool_name
);
1097 (Some(tool_name
), lint_name
)
1099 None
=> (None
, lint_name
),