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_session::lint::{builtin, Level, Lint, LintId};
9 use rustc_session::{DiagnosticMessageId, Session};
10 use rustc_span::hygiene::MacroKind;
11 use rustc_span::source_map::{DesugaringKind, ExpnKind, MultiSpan};
12 use rustc_span::{symbol, Span, Symbol, DUMMY_SP};
14 /// How a lint level was set.
15 #[derive(Clone, Copy, PartialEq, Eq, HashStable)]
17 /// Lint is at the default level as declared
18 /// in rustc or a plugin.
21 /// Lint level was set by an attribute.
22 Node(Symbol, Span, Option<Symbol> /* RFC 2383 reason */),
24 /// Lint level was set by a command-line flag.
25 /// The provided `Level` is the level specified on the command line -
26 /// the actual level may be lower due to `--cap-lints`
27 CommandLine(Symbol, Level),
31 pub fn name(&self) -> Symbol {
33 LintSource::Default => symbol::kw::Default,
34 LintSource::Node(name, _, _) => name,
35 LintSource::CommandLine(name, _) => name,
39 pub fn span(&self) -> Span {
41 LintSource::Default => DUMMY_SP,
42 LintSource::Node(_, span, _) => span,
43 LintSource::CommandLine(_, _) => DUMMY_SP,
48 pub type LevelSource = (Level, LintSource);
50 pub struct LintLevelSets {
51 pub list: Vec<LintSet>,
57 // -A,-W,-D flags, a `Symbol` for the flag itself and `Level` for which
59 specs: FxHashMap<LintId, LevelSource>,
63 specs: FxHashMap<LintId, LevelSource>,
69 pub fn new() -> Self {
70 LintLevelSets { list: Vec::new(), lint_cap: Level::Forbid }
73 pub fn get_lint_level(
77 aux: Option<&FxHashMap<LintId, LevelSource>>,
80 let (level, mut src) = self.get_lint_id_level(LintId::of(lint), idx, aux);
82 // If `level` is none then we actually assume the default level for this
84 let mut level = level.unwrap_or_else(|| lint.default_level(sess.edition()));
86 // If we're about to issue a warning, check at the last minute for any
87 // directives against the warnings "lint". If, for example, there's an
88 // `allow(warnings)` in scope then we want to respect that instead.
89 if level == Level::Warn {
90 let (warnings_level, warnings_src) =
91 self.get_lint_id_level(LintId::of(builtin::WARNINGS), idx, aux);
92 if let Some(configured_warning_level) = warnings_level {
93 if configured_warning_level != Level::Warn {
94 level = configured_warning_level;
100 // Ensure that we never exceed the `--cap-lints` argument.
101 level = cmp::min(level, self.lint_cap);
103 if let Some(driver_level) = sess.driver_lint_caps.get(&LintId::of(lint)) {
104 // Ensure that we never exceed driver level.
105 level = cmp::min(*driver_level, level);
111 pub fn get_lint_id_level(
115 aux: Option<&FxHashMap<LintId, LevelSource>>,
116 ) -> (Option<Level>, LintSource) {
117 if let Some(specs) = aux {
118 if let Some(&(level, src)) = specs.get(&id) {
119 return (Some(level), src);
123 match self.list[idx as usize] {
124 LintSet::CommandLine { ref specs } => {
125 if let Some(&(level, src)) = specs.get(&id) {
126 return (Some(level), src);
128 return (None, LintSource::Default);
130 LintSet::Node { ref specs, parent } => {
131 if let Some(&(level, src)) = specs.get(&id) {
132 return (Some(level), src);
141 pub struct LintLevelMap {
142 pub sets: LintLevelSets,
143 pub id_to_set: FxHashMap<HirId, u32>,
147 /// If the `id` was previously registered with `register_id` when building
148 /// this `LintLevelMap` this returns the corresponding lint level and source
149 /// of the lint level for the lint provided.
151 /// If the `id` was not previously registered, returns `None`. If `None` is
152 /// returned then the parent of `id` should be acquired and this function
153 /// should be called again.
154 pub fn level_and_source(
159 ) -> Option<LevelSource> {
160 self.id_to_set.get(&id).map(|idx| self.sets.get_lint_level(lint, *idx, None, session))
164 impl<'a> HashStable<StableHashingContext<'a>> for LintLevelMap {
166 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
167 let LintLevelMap { ref sets, ref id_to_set } = *self;
169 id_to_set.hash_stable(hcx, hasher);
171 let LintLevelSets { ref list, lint_cap } = *sets;
173 lint_cap.hash_stable(hcx, hasher);
175 hcx.while_hashing_spans(true, |hcx| {
176 list.len().hash_stable(hcx, hasher);
178 // We are working under the assumption here that the list of
179 // lint-sets is built in a deterministic order.
180 for lint_set in list {
181 ::std::mem::discriminant(lint_set).hash_stable(hcx, hasher);
184 LintSet::CommandLine { ref specs } => {
185 specs.hash_stable(hcx, hasher);
187 LintSet::Node { ref specs, parent } => {
188 specs.hash_stable(hcx, hasher);
189 parent.hash_stable(hcx, hasher);
197 pub struct LintDiagnosticBuilder<'a>(DiagnosticBuilder<'a>);
199 impl<'a> LintDiagnosticBuilder<'a> {
200 /// Return the inner DiagnosticBuilder, first setting the primary message to `msg`.
201 pub fn build(mut self, msg: &str) -> DiagnosticBuilder<'a> {
202 self.0.set_primary_message(msg);
206 /// Create a LintDiagnosticBuilder from some existing DiagnosticBuilder.
207 pub fn new(err: DiagnosticBuilder<'a>) -> LintDiagnosticBuilder<'a> {
208 LintDiagnosticBuilder(err)
212 pub fn struct_lint_level<'s, 'd>(
217 span: Option<MultiSpan>,
218 decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a>) + 'd,
220 // Avoid codegen bloat from monomorphization by immediately doing dyn dispatch of `decorate` to
222 fn struct_lint_level_impl(
227 span: Option<MultiSpan>,
228 decorate: Box<dyn for<'b> FnOnce(LintDiagnosticBuilder<'b>) + 'd>,
230 // Check for future incompatibility lints and issue a stronger warning.
231 let lint_id = LintId::of(lint);
232 let future_incompatible = lint.future_incompatible;
234 let has_future_breakage =
235 future_incompatible.map_or(false, |incompat| incompat.future_breakage.is_some());
237 let mut err = match (level, span) {
238 (Level::Allow, span) => {
239 if has_future_breakage {
240 if let Some(span) = span {
241 sess.struct_span_allow(span, "")
243 sess.struct_allow("")
249 (Level::Warn, Some(span)) => sess.struct_span_warn(span, ""),
250 (Level::Warn, None) => sess.struct_warn(""),
251 (Level::Deny | Level::Forbid, Some(span)) => sess.struct_span_err(span, ""),
252 (Level::Deny | Level::Forbid, None) => sess.struct_err(""),
255 // If this code originates in a foreign macro, aka something that this crate
256 // did not itself author, then it's likely that there's nothing this crate
257 // can do about it. We probably want to skip the lint entirely.
258 if err.span.primary_spans().iter().any(|s| in_external_macro(sess, *s)) {
259 // Any suggestions made here are likely to be incorrect, so anything we
260 // emit shouldn't be automatically fixed by rustfix.
261 err.allow_suggestions(false);
263 // If this is a future incompatible lint it'll become a hard error, so
264 // we have to emit *something*. Also, if this lint occurs in the
265 // expansion of a macro from an external crate, allow individual lints
266 // to opt-out from being reported.
267 if future_incompatible.is_none() && !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 LintSource::Default => {
280 DiagnosticMessageId::from(lint),
281 &format!("`#[{}({})]` on by default", level.as_str(), name),
284 LintSource::CommandLine(lint_flag_val, orig_level) => {
285 let flag = match orig_level {
288 Level::Forbid => "-F",
289 Level::Allow => "-A",
291 let hyphen_case_lint_name = name.replace("_", "-");
292 if lint_flag_val.as_str() == name {
295 DiagnosticMessageId::from(lint),
297 "requested on the command line with `{} {}`",
298 flag, hyphen_case_lint_name
302 let hyphen_case_flag_val = lint_flag_val.as_str().replace("_", "-");
305 DiagnosticMessageId::from(lint),
307 "`{} {}` implied by `{} {}`",
308 flag, hyphen_case_lint_name, flag, hyphen_case_flag_val
313 LintSource::Node(lint_attr_name, src, reason) => {
314 if let Some(rationale) = reason {
315 err.note(&rationale.as_str());
317 sess.diag_span_note_once(
319 DiagnosticMessageId::from(lint),
321 "the lint level is defined here",
323 if lint_attr_name.as_str() != name {
324 let level_str = level.as_str();
327 DiagnosticMessageId::from(lint),
329 "`#[{}({})]` implied by `#[{}({})]`",
330 level_str, name, level_str, lint_attr_name
337 err.code(DiagnosticId::Lint { name, has_future_breakage });
339 if let Some(future_incompatible) = future_incompatible {
340 const STANDARD_MESSAGE: &str = "this was previously accepted by the compiler but is being phased out; \
341 it will become a hard error";
343 let explanation = if lint_id == LintId::of(builtin::UNSTABLE_NAME_COLLISIONS) {
344 "once this method is added to the standard library, \
345 the ambiguity may cause an error or change in behavior!"
347 } else if lint_id == LintId::of(builtin::MUTABLE_BORROW_RESERVATION_CONFLICT) {
348 "this borrowing pattern was not meant to be accepted, \
349 and may become a hard error in the future"
351 } else if let Some(edition) = future_incompatible.edition {
352 format!("{} in the {} edition!", STANDARD_MESSAGE, edition)
354 format!("{} in a future release!", STANDARD_MESSAGE)
356 let citation = format!("for more information, see {}", future_incompatible.reference);
357 err.warn(&explanation);
361 // Finally, run `decorate`. This function is also responsible for emitting the diagnostic.
362 decorate(LintDiagnosticBuilder::new(err));
364 struct_lint_level_impl(sess, lint, level, src, span, Box::new(decorate))
367 /// Returns whether `span` originates in a foreign crate's external macro.
369 /// This is used to test whether a lint should not even begin to figure out whether it should
370 /// be reported on the current node.
371 pub fn in_external_macro(sess: &Session, span: Span) -> bool {
372 let expn_data = span.ctxt().outer_expn_data();
373 match expn_data.kind {
374 ExpnKind::Inlined | ExpnKind::Root | ExpnKind::Desugaring(DesugaringKind::ForLoop(_)) => {
377 ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) => true, // well, it's "external"
378 ExpnKind::Macro(MacroKind::Bang, _) => {
379 // Dummy span for the `def_site` means it's an external macro.
380 expn_data.def_site.is_dummy() || sess.source_map().is_imported(expn_data.def_site)
382 ExpnKind::Macro { .. } => true, // definitely a plugin