06bc4fc671
* instead simply set the primary message inside the lint decorator functions * it used to be this way before [#]101986 which introduced `msg` to prevent good path delayed bugs (which no longer exist) from firing under certain circumstances when lints were suppressed / silenced * this is no longer necessary for various reasons I presume * it shaves off complexity and makes further changes easier to implement
449 lines
18 KiB
Rust
449 lines
18 KiB
Rust
use std::cmp;
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use rustc_data_structures::fx::FxIndexMap;
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use rustc_data_structures::sorted_map::SortedMap;
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use rustc_errors::{Diag, MultiSpan};
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use rustc_hir::{HirId, ItemLocalId};
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use rustc_macros::HashStable;
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use rustc_session::lint::{
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builtin::{self, FORBIDDEN_LINT_GROUPS},
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FutureIncompatibilityReason, Level, Lint, LintId,
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};
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use rustc_session::Session;
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use rustc_span::hygiene::{ExpnKind, MacroKind};
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use rustc_span::{symbol, DesugaringKind, Span, Symbol, DUMMY_SP};
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use crate::ty::TyCtxt;
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/// How a lint level was set.
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#[derive(Clone, Copy, PartialEq, Eq, HashStable, Debug)]
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pub enum LintLevelSource {
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/// Lint is at the default level as declared in rustc.
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Default,
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/// Lint level was set by an attribute.
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Node {
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name: Symbol,
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span: Span,
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/// RFC 2383 reason
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reason: Option<Symbol>,
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},
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/// Lint level was set by a command-line flag.
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/// The provided `Level` is the level specified on the command line.
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/// (The actual level may be lower due to `--cap-lints`.)
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CommandLine(Symbol, Level),
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}
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impl LintLevelSource {
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pub fn name(&self) -> Symbol {
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match *self {
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LintLevelSource::Default => symbol::kw::Default,
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LintLevelSource::Node { name, .. } => name,
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LintLevelSource::CommandLine(name, _) => name,
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}
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}
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pub fn span(&self) -> Span {
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match *self {
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LintLevelSource::Default => DUMMY_SP,
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LintLevelSource::Node { span, .. } => span,
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LintLevelSource::CommandLine(_, _) => DUMMY_SP,
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}
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}
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}
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/// A tuple of a lint level and its source.
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pub type LevelAndSource = (Level, LintLevelSource);
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/// Return type for the `shallow_lint_levels_on` query.
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///
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/// This map represents the set of allowed lints and allowance levels given
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/// by the attributes for *a single HirId*.
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#[derive(Default, Debug, HashStable)]
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pub struct ShallowLintLevelMap {
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pub specs: SortedMap<ItemLocalId, FxIndexMap<LintId, LevelAndSource>>,
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}
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/// From an initial level and source, verify the effect of special annotations:
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/// `warnings` lint level and lint caps.
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///
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/// The return of this function is suitable for diagnostics.
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pub fn reveal_actual_level(
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level: Option<Level>,
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src: &mut LintLevelSource,
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sess: &Session,
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lint: LintId,
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probe_for_lint_level: impl FnOnce(LintId) -> (Option<Level>, LintLevelSource),
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) -> Level {
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// If `level` is none then we actually assume the default level for this lint.
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let mut level = level.unwrap_or_else(|| lint.lint.default_level(sess.edition()));
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// If we're about to issue a warning, check at the last minute for any
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// directives against the warnings "lint". If, for example, there's an
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// `allow(warnings)` in scope then we want to respect that instead.
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//
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// We exempt `FORBIDDEN_LINT_GROUPS` from this because it specifically
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// triggers in cases (like #80988) where you have `forbid(warnings)`,
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// and so if we turned that into an error, it'd defeat the purpose of the
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// future compatibility warning.
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if level == Level::Warn && lint != LintId::of(FORBIDDEN_LINT_GROUPS) {
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let (warnings_level, warnings_src) = probe_for_lint_level(LintId::of(builtin::WARNINGS));
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if let Some(configured_warning_level) = warnings_level {
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if configured_warning_level != Level::Warn {
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level = configured_warning_level;
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*src = warnings_src;
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}
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}
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}
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// Ensure that we never exceed the `--cap-lints` argument unless the source is a --force-warn
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level = if let LintLevelSource::CommandLine(_, Level::ForceWarn(_)) = src {
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level
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} else {
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cmp::min(level, sess.opts.lint_cap.unwrap_or(Level::Forbid))
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};
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if let Some(driver_level) = sess.driver_lint_caps.get(&lint) {
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// Ensure that we never exceed driver level.
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level = cmp::min(*driver_level, level);
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}
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level
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}
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impl ShallowLintLevelMap {
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/// Perform a deep probe in the HIR tree looking for the actual level for the lint.
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/// This lint level is not usable for diagnostics, it needs to be corrected by
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/// `reveal_actual_level` beforehand.
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#[instrument(level = "trace", skip(self, tcx), ret)]
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fn probe_for_lint_level(
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&self,
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tcx: TyCtxt<'_>,
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id: LintId,
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start: HirId,
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) -> (Option<Level>, LintLevelSource) {
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if let Some(map) = self.specs.get(&start.local_id)
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&& let Some(&(level, src)) = map.get(&id)
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{
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return (Some(level), src);
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}
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let mut owner = start.owner;
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let mut specs = &self.specs;
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for parent in tcx.hir().parent_id_iter(start) {
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if parent.owner != owner {
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owner = parent.owner;
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specs = &tcx.shallow_lint_levels_on(owner).specs;
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}
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if let Some(map) = specs.get(&parent.local_id)
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&& let Some(&(level, src)) = map.get(&id)
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{
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return (Some(level), src);
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}
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}
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(None, LintLevelSource::Default)
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}
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/// Fetch and return the user-visible lint level for the given lint at the given HirId.
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#[instrument(level = "trace", skip(self, tcx), ret)]
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pub fn lint_level_id_at_node(
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&self,
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tcx: TyCtxt<'_>,
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lint: LintId,
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cur: HirId,
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) -> (Level, LintLevelSource) {
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let (level, mut src) = self.probe_for_lint_level(tcx, lint, cur);
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let level = reveal_actual_level(level, &mut src, tcx.sess, lint, |lint| {
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self.probe_for_lint_level(tcx, lint, cur)
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});
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(level, src)
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}
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}
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impl TyCtxt<'_> {
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/// Fetch and return the user-visible lint level for the given lint at the given HirId.
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pub fn lint_level_at_node(self, lint: &'static Lint, id: HirId) -> (Level, LintLevelSource) {
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self.shallow_lint_levels_on(id.owner).lint_level_id_at_node(self, LintId::of(lint), id)
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}
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}
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/// This struct represents a lint expectation and holds all required information
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/// to emit the `unfulfilled_lint_expectations` lint if it is unfulfilled after
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/// the `LateLintPass` has completed.
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#[derive(Clone, Debug, HashStable)]
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pub struct LintExpectation {
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/// The reason for this expectation that can optionally be added as part of
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/// the attribute. It will be displayed as part of the lint message.
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pub reason: Option<Symbol>,
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/// The [`Span`] of the attribute that this expectation originated from.
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pub emission_span: Span,
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/// Lint messages for the `unfulfilled_lint_expectations` lint will be
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/// adjusted to include an additional note. Therefore, we have to track if
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/// the expectation is for the lint.
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pub is_unfulfilled_lint_expectations: bool,
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/// This will hold the name of the tool that this lint belongs to. For
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/// the lint `clippy::some_lint` the tool would be `clippy`, the same
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/// goes for `rustdoc`. This will be `None` for rustc lints
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pub lint_tool: Option<Symbol>,
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}
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impl LintExpectation {
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pub fn new(
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reason: Option<Symbol>,
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emission_span: Span,
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is_unfulfilled_lint_expectations: bool,
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lint_tool: Option<Symbol>,
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) -> Self {
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Self { reason, emission_span, is_unfulfilled_lint_expectations, lint_tool }
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}
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}
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pub fn explain_lint_level_source(
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lint: &'static Lint,
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level: Level,
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src: LintLevelSource,
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err: &mut Diag<'_, ()>,
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) {
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let name = lint.name_lower();
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if let Level::Allow = level {
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// Do not point at `#[allow(compat_lint)]` as the reason for a compatibility lint
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// triggering. (#121009)
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return;
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}
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match src {
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LintLevelSource::Default => {
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err.note_once(format!("`#[{}({})]` on by default", level.as_str(), name));
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}
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LintLevelSource::CommandLine(lint_flag_val, orig_level) => {
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let flag = orig_level.to_cmd_flag();
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let hyphen_case_lint_name = name.replace('_', "-");
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if lint_flag_val.as_str() == name {
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err.note_once(format!(
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"requested on the command line with `{flag} {hyphen_case_lint_name}`"
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));
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} else {
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let hyphen_case_flag_val = lint_flag_val.as_str().replace('_', "-");
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err.note_once(format!(
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"`{flag} {hyphen_case_lint_name}` implied by `{flag} {hyphen_case_flag_val}`"
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));
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err.help_once(format!(
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"to override `{flag} {hyphen_case_flag_val}` add `#[allow({name})]`"
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));
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}
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}
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LintLevelSource::Node { name: lint_attr_name, span, reason, .. } => {
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if let Some(rationale) = reason {
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err.note(rationale.to_string());
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}
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err.span_note_once(span, "the lint level is defined here");
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if lint_attr_name.as_str() != name {
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let level_str = level.as_str();
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err.note_once(format!(
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"`#[{level_str}({name})]` implied by `#[{level_str}({lint_attr_name})]`"
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));
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}
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}
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}
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}
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/// The innermost function for emitting lints.
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///
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/// If you are looking to implement a lint, look for higher level functions,
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/// for example:
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/// - [`TyCtxt::emit_node_span_lint`]
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/// - [`TyCtxt::node_span_lint`]
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/// - [`TyCtxt::emit_node_lint`]
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/// - [`TyCtxt::node_lint`]
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/// - `LintContext::opt_span_lint`
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///
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/// ## `decorate`
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///
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/// It is not intended to call `emit`/`cancel` on the `Diag` passed in the `decorate` callback.
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#[track_caller]
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pub fn lint_level(
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sess: &Session,
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lint: &'static Lint,
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level: Level,
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src: LintLevelSource,
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span: Option<MultiSpan>,
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decorate: impl for<'a, 'b> FnOnce(&'b mut Diag<'a, ()>),
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) {
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// Avoid codegen bloat from monomorphization by immediately doing dyn dispatch of `decorate` to
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// the "real" work.
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#[track_caller]
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fn lint_level_impl(
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sess: &Session,
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lint: &'static Lint,
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level: Level,
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src: LintLevelSource,
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span: Option<MultiSpan>,
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decorate: Box<dyn '_ + for<'a, 'b> FnOnce(&'b mut Diag<'a, ()>)>,
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) {
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// Check for future incompatibility lints and issue a stronger warning.
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let future_incompatible = lint.future_incompatible;
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let has_future_breakage = future_incompatible.map_or(
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// Default allow lints trigger too often for testing.
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sess.opts.unstable_opts.future_incompat_test && lint.default_level != Level::Allow,
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|incompat| {
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matches!(
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incompat.reason,
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FutureIncompatibilityReason::FutureReleaseErrorReportInDeps
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)
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},
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);
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// Convert lint level to error level.
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let err_level = match level {
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Level::Allow => {
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if has_future_breakage {
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rustc_errors::Level::Allow
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} else {
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return;
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}
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}
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Level::Expect(expect_id) => {
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// This case is special as we actually allow the lint itself in this context, but
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// we can't return early like in the case for `Level::Allow` because we still
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// need the lint diagnostic to be emitted to `rustc_error::DiagCtxtInner`.
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//
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// We can also not mark the lint expectation as fulfilled here right away, as it
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// can still be cancelled in the decorate function. All of this means that we simply
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// create a `Diag` and continue as we would for warnings.
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rustc_errors::Level::Expect(expect_id)
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}
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Level::ForceWarn(Some(expect_id)) => rustc_errors::Level::ForceWarning(Some(expect_id)),
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Level::ForceWarn(None) => rustc_errors::Level::ForceWarning(None),
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Level::Warn => rustc_errors::Level::Warning,
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Level::Deny | Level::Forbid => rustc_errors::Level::Error,
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};
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let mut err = Diag::new(sess.dcx(), err_level, "");
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if let Some(span) = span {
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err.span(span);
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}
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// If this code originates in a foreign macro, aka something that this crate
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// did not itself author, then it's likely that there's nothing this crate
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// can do about it. We probably want to skip the lint entirely.
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if err.span.primary_spans().iter().any(|s| in_external_macro(sess, *s)) {
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// Any suggestions made here are likely to be incorrect, so anything we
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// emit shouldn't be automatically fixed by rustfix.
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err.disable_suggestions();
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// If this is a future incompatible that is not an edition fixing lint
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// it'll become a hard error, so we have to emit *something*. Also,
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// if this lint occurs in the expansion of a macro from an external crate,
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// allow individual lints to opt-out from being reported.
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let incompatible = future_incompatible.is_some_and(|f| f.reason.edition().is_none());
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if !incompatible && !lint.report_in_external_macro {
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err.cancel();
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// Don't continue further, since we don't want to have
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// `diag_span_note_once` called for a diagnostic that isn't emitted.
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return;
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}
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}
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err.is_lint(lint.name_lower(), has_future_breakage);
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// Lint diagnostics that are covered by the expect level will not be emitted outside
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// the compiler. It is therefore not necessary to add any information for the user.
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// This will therefore directly call the decorate function which will in turn emit
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// the diagnostic.
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if let Level::Expect(_) = level {
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decorate(&mut err);
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err.emit();
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return;
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}
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if let Some(future_incompatible) = future_incompatible {
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let explanation = match future_incompatible.reason {
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FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps
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| FutureIncompatibilityReason::FutureReleaseErrorReportInDeps => {
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"this was previously accepted by the compiler but is being phased out; \
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it will become a hard error in a future release!"
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.to_owned()
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}
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FutureIncompatibilityReason::FutureReleaseSemanticsChange => {
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"this will change its meaning in a future release!".to_owned()
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}
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FutureIncompatibilityReason::EditionError(edition) => {
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let current_edition = sess.edition();
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format!(
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"this is accepted in the current edition (Rust {current_edition}) but is a hard error in Rust {edition}!"
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)
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}
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FutureIncompatibilityReason::EditionSemanticsChange(edition) => {
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format!("this changes meaning in Rust {edition}")
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}
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FutureIncompatibilityReason::Custom(reason) => reason.to_owned(),
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};
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if future_incompatible.explain_reason {
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err.warn(explanation);
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}
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if !future_incompatible.reference.is_empty() {
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let citation =
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format!("for more information, see {}", future_incompatible.reference);
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err.note(citation);
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}
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}
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// Finally, run `decorate`. `decorate` can call `trimmed_path_str` (directly or indirectly),
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// so we need to make sure when we do call `decorate` that the diagnostic is eventually
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// emitted or we'll get a `must_produce_diag` ICE.
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//
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// When is a diagnostic *eventually* emitted? Well, that is determined by 2 factors:
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// 1. If the corresponding `rustc_errors::Level` is beyond warning, i.e. `ForceWarning(_)`
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// or `Error`, then the diagnostic will be emitted regardless of CLI options.
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// 2. If the corresponding `rustc_errors::Level` is warning, then that can be affected by
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// `-A warnings` or `--cap-lints=xxx` on the command line. In which case, the diagnostic
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// will be emitted if `can_emit_warnings` is true.
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let skip = err_level == rustc_errors::Level::Warning && !sess.dcx().can_emit_warnings();
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if !skip {
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decorate(&mut err);
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}
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explain_lint_level_source(lint, level, src, &mut err);
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err.emit()
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}
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lint_level_impl(sess, lint, level, src, span, Box::new(decorate))
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}
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/// Returns whether `span` originates in a foreign crate's external macro.
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///
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/// This is used to test whether a lint should not even begin to figure out whether it should
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/// be reported on the current node.
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pub fn in_external_macro(sess: &Session, span: Span) -> bool {
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let expn_data = span.ctxt().outer_expn_data();
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match expn_data.kind {
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ExpnKind::Root
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| ExpnKind::Desugaring(
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DesugaringKind::ForLoop
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| DesugaringKind::WhileLoop
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| DesugaringKind::OpaqueTy
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| DesugaringKind::Async
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| DesugaringKind::Await,
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) => false,
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ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) => true, // well, it's "external"
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ExpnKind::Macro(MacroKind::Bang, _) => {
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// Dummy span for the `def_site` means it's an external macro.
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expn_data.def_site.is_dummy() || sess.source_map().is_imported(expn_data.def_site)
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}
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ExpnKind::Macro { .. } => true, // definitely a plugin
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}
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}
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/// Return whether `span` is generated by `async` or `await`.
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|
pub fn is_from_async_await(span: Span) -> bool {
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let expn_data = span.ctxt().outer_expn_data();
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match expn_data.kind {
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ExpnKind::Desugaring(DesugaringKind::Async | DesugaringKind::Await) => true,
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_ => false,
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}
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}
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