3 use crate::ich::StableHashingContext;
4 use rustc_data_structures::fx::FxHashMap;
5 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
6 use rustc_errors::{DiagnosticBuilder, DiagnosticId};
8 use rustc_index::vec::IndexVec;
9 use rustc_session::lint::{
10 builtin::{self, FORBIDDEN_LINT_GROUPS},
11 FutureIncompatibilityReason, Level, Lint, LintId,
13 use rustc_session::{DiagnosticMessageId, Session};
14 use rustc_span::hygiene::MacroKind;
15 use rustc_span::source_map::{DesugaringKind, ExpnKind, MultiSpan};
16 use rustc_span::{symbol, Span, Symbol, DUMMY_SP};
18 /// How a lint level was set.
19 #[derive(Clone, Copy, PartialEq, Eq, HashStable, Debug)]
20 pub enum LintLevelSource {
21 /// Lint is at the default level as declared
22 /// in rustc or a plugin.
25 /// Lint level was set by an attribute.
26 Node(Symbol, Span, Option<Symbol> /* RFC 2383 reason */),
28 /// Lint level was set by a command-line flag.
29 /// The provided `Level` is the level specified on the command line.
30 /// (The actual level may be lower due to `--cap-lints`.)
31 CommandLine(Symbol, Level),
34 impl LintLevelSource {
35 pub fn name(&self) -> Symbol {
37 LintLevelSource::Default => symbol::kw::Default,
38 LintLevelSource::Node(name, _, _) => name,
39 LintLevelSource::CommandLine(name, _) => name,
43 pub fn span(&self) -> Span {
45 LintLevelSource::Default => DUMMY_SP,
46 LintLevelSource::Node(_, span, _) => span,
47 LintLevelSource::CommandLine(_, _) => DUMMY_SP,
52 /// A tuple of a lint level and its source.
53 pub type LevelAndSource = (Level, LintLevelSource);
55 #[derive(Debug, HashStable)]
56 pub struct LintLevelSets {
57 pub list: IndexVec<LintStackIndex, LintSet>,
61 rustc_index::newtype_index! {
63 pub struct LintStackIndex {
64 const COMMAND_LINE = 0,
68 #[derive(Debug, HashStable)]
71 // -A,-W,-D flags, a `Symbol` for the flag itself and `Level` for which
73 specs: FxHashMap<LintId, LevelAndSource>,
77 specs: FxHashMap<LintId, LevelAndSource>,
78 parent: LintStackIndex,
83 pub fn new() -> Self {
84 LintLevelSets { list: IndexVec::new(), lint_cap: Level::Forbid }
87 pub fn get_lint_level(
91 aux: Option<&FxHashMap<LintId, LevelAndSource>>,
94 let (level, mut src) = self.get_lint_id_level(LintId::of(lint), idx, aux);
96 // If `level` is none then we actually assume the default level for this
98 let mut level = level.unwrap_or_else(|| lint.default_level(sess.edition()));
100 // If we're about to issue a warning, check at the last minute for any
101 // directives against the warnings "lint". If, for example, there's an
102 // `allow(warnings)` in scope then we want to respect that instead.
104 // We exempt `FORBIDDEN_LINT_GROUPS` from this because it specifically
105 // triggers in cases (like #80988) where you have `forbid(warnings)`,
106 // and so if we turned that into an error, it'd defeat the purpose of the
107 // future compatibility warning.
108 if level == Level::Warn && LintId::of(lint) != LintId::of(FORBIDDEN_LINT_GROUPS) {
109 let (warnings_level, warnings_src) =
110 self.get_lint_id_level(LintId::of(builtin::WARNINGS), idx, aux);
111 if let Some(configured_warning_level) = warnings_level {
112 if configured_warning_level != Level::Warn {
113 level = configured_warning_level;
119 // Ensure that we never exceed the `--cap-lints` argument.
120 level = cmp::min(level, self.lint_cap);
122 if let Some(driver_level) = sess.driver_lint_caps.get(&LintId::of(lint)) {
123 // Ensure that we never exceed driver level.
124 level = cmp::min(*driver_level, level);
130 pub fn get_lint_id_level(
133 mut idx: LintStackIndex,
134 aux: Option<&FxHashMap<LintId, LevelAndSource>>,
135 ) -> (Option<Level>, LintLevelSource) {
136 if let Some(specs) = aux {
137 if let Some(&(level, src)) = specs.get(&id) {
138 return (Some(level), src);
142 match self.list[idx] {
143 LintSet::CommandLine { ref specs } => {
144 if let Some(&(level, src)) = specs.get(&id) {
145 return (Some(level), src);
147 return (None, LintLevelSource::Default);
149 LintSet::Node { ref specs, parent } => {
150 if let Some(&(level, src)) = specs.get(&id) {
151 return (Some(level), src);
161 pub struct LintLevelMap {
162 pub sets: LintLevelSets,
163 pub id_to_set: FxHashMap<HirId, LintStackIndex>,
167 /// If the `id` was previously registered with `register_id` when building
168 /// this `LintLevelMap` this returns the corresponding lint level and source
169 /// of the lint level for the lint provided.
171 /// If the `id` was not previously registered, returns `None`. If `None` is
172 /// returned then the parent of `id` should be acquired and this function
173 /// should be called again.
174 pub fn level_and_source(
179 ) -> Option<LevelAndSource> {
180 self.id_to_set.get(&id).map(|idx| self.sets.get_lint_level(lint, *idx, None, session))
184 impl<'a> HashStable<StableHashingContext<'a>> for LintLevelMap {
186 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
187 let LintLevelMap { ref sets, ref id_to_set } = *self;
189 id_to_set.hash_stable(hcx, hasher);
191 hcx.while_hashing_spans(true, |hcx| sets.hash_stable(hcx, hasher))
195 pub struct LintDiagnosticBuilder<'a>(DiagnosticBuilder<'a>);
197 impl<'a> LintDiagnosticBuilder<'a> {
198 /// Return the inner DiagnosticBuilder, first setting the primary message to `msg`.
199 pub fn build(mut self, msg: &str) -> DiagnosticBuilder<'a> {
200 self.0.set_primary_message(msg);
204 /// Create a LintDiagnosticBuilder from some existing DiagnosticBuilder.
205 pub fn new(err: DiagnosticBuilder<'a>) -> LintDiagnosticBuilder<'a> {
206 LintDiagnosticBuilder(err)
210 pub fn struct_lint_level<'s, 'd>(
214 src: LintLevelSource,
215 span: Option<MultiSpan>,
216 decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a>) + 'd,
218 // Avoid codegen bloat from monomorphization by immediately doing dyn dispatch of `decorate` to
220 fn struct_lint_level_impl(
224 src: LintLevelSource,
225 span: Option<MultiSpan>,
226 decorate: Box<dyn for<'b> FnOnce(LintDiagnosticBuilder<'b>) + 'd>,
228 // Check for future incompatibility lints and issue a stronger warning.
229 let lint_id = LintId::of(lint);
230 let future_incompatible = lint.future_incompatible;
232 let has_future_breakage =
233 future_incompatible.map_or(false, |incompat| incompat.future_breakage.is_some());
235 let mut err = match (level, span) {
236 (Level::Allow, span) => {
237 if has_future_breakage {
238 if let Some(span) = span {
239 sess.struct_span_allow(span, "")
241 sess.struct_allow("")
247 (Level::Warn | Level::ForceWarn, Some(span)) => sess.struct_span_warn(span, ""),
248 (Level::Warn | Level::ForceWarn, None) => sess.struct_warn(""),
249 (Level::Deny | Level::Forbid, Some(span)) => sess.struct_span_err(span, ""),
250 (Level::Deny | Level::Forbid, None) => sess.struct_err(""),
253 // If this code originates in a foreign macro, aka something that this crate
254 // did not itself author, then it's likely that there's nothing this crate
255 // can do about it. We probably want to skip the lint entirely.
256 if err.span.primary_spans().iter().any(|s| in_external_macro(sess, *s)) {
257 // Any suggestions made here are likely to be incorrect, so anything we
258 // emit shouldn't be automatically fixed by rustfix.
259 err.allow_suggestions(false);
261 // If this is a future incompatible that is not an edition fixing lint
262 // it'll become a hard error, so we have to emit *something*. Also,
263 // if this lint occurs in the expansion of a macro from an external crate,
264 // allow individual lints to opt-out from being reported.
265 let not_future_incompatible =
266 future_incompatible.map(|f| f.reason.edition().is_some()).unwrap_or(true);
267 if not_future_incompatible && !lint.report_in_external_macro {
269 // Don't continue further, since we don't want to have
270 // `diag_span_note_once` called for a diagnostic that isn't emitted.
275 let name = lint.name_lower();
277 LintLevelSource::Default => {
280 DiagnosticMessageId::from(lint),
281 &format!("`#[{}({})]` on by default", level.as_str(), name),
284 LintLevelSource::CommandLine(lint_flag_val, orig_level) => {
285 let flag = match orig_level {
288 Level::Forbid => "-F",
289 Level::Allow => "-A",
290 Level::ForceWarn => "--force-warns",
292 let hyphen_case_lint_name = name.replace("_", "-");
293 if lint_flag_val.as_str() == name {
296 DiagnosticMessageId::from(lint),
298 "requested on the command line with `{} {}`",
299 flag, hyphen_case_lint_name
303 let hyphen_case_flag_val = lint_flag_val.as_str().replace("_", "-");
306 DiagnosticMessageId::from(lint),
308 "`{} {}` implied by `{} {}`",
309 flag, hyphen_case_lint_name, flag, hyphen_case_flag_val
314 LintLevelSource::Node(lint_attr_name, src, reason) => {
315 if let Some(rationale) = reason {
316 err.note(&rationale.as_str());
318 sess.diag_span_note_once(
320 DiagnosticMessageId::from(lint),
322 "the lint level is defined here",
324 if lint_attr_name.as_str() != name {
325 let level_str = level.as_str();
328 DiagnosticMessageId::from(lint),
330 "`#[{}({})]` implied by `#[{}({})]`",
331 level_str, name, level_str, lint_attr_name
338 err.code(DiagnosticId::Lint { name, has_future_breakage });
340 if let Some(future_incompatible) = future_incompatible {
341 let explanation = if lint_id == LintId::of(builtin::UNSTABLE_NAME_COLLISIONS) {
342 "once this associated item is added to the standard library, the ambiguity may \
343 cause an error or change in behavior!"
345 } else if lint_id == LintId::of(builtin::MUTABLE_BORROW_RESERVATION_CONFLICT) {
346 "this borrowing pattern was not meant to be accepted, and may become a hard error \
349 } else if let FutureIncompatibilityReason::EditionError(edition) =
350 future_incompatible.reason
352 let current_edition = sess.edition();
354 "this is accepted in the current edition (Rust {}) but is a hard error in Rust {}!",
355 current_edition, edition
357 } else if let FutureIncompatibilityReason::EditionSemanticsChange(edition) =
358 future_incompatible.reason
360 format!("this changes meaning in Rust {}", edition)
362 "this was previously accepted by the compiler but is being phased out; \
363 it will become a hard error in a future release!"
366 if future_incompatible.explain_reason {
367 err.warn(&explanation);
369 if !future_incompatible.reference.is_empty() {
371 format!("for more information, see {}", future_incompatible.reference);
376 // Finally, run `decorate`. This function is also responsible for emitting the diagnostic.
377 decorate(LintDiagnosticBuilder::new(err));
379 struct_lint_level_impl(sess, lint, level, src, span, Box::new(decorate))
382 /// Returns whether `span` originates in a foreign crate's external macro.
384 /// This is used to test whether a lint should not even begin to figure out whether it should
385 /// be reported on the current node.
386 pub fn in_external_macro(sess: &Session, span: Span) -> bool {
387 let expn_data = span.ctxt().outer_expn_data();
388 match expn_data.kind {
389 ExpnKind::Inlined | ExpnKind::Root | ExpnKind::Desugaring(DesugaringKind::ForLoop(_)) => {
392 ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) => true, // well, it's "external"
393 ExpnKind::Macro { kind: MacroKind::Bang, name: _, proc_macro: _ } => {
394 // Dummy span for the `def_site` means it's an external macro.
395 expn_data.def_site.is_dummy() || sess.source_map().is_imported(expn_data.def_site)
397 ExpnKind::Macro { .. } => true, // definitely a plugin