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use std::cmp;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::sorted_map::SortedMap;
use rustc_errors::{Diagnostic, DiagnosticBuilder, DiagnosticId, DiagnosticMessage, MultiSpan};
use rustc_hir::{HirId, ItemLocalId};
use rustc_session::lint::{
builtin::{self, FORBIDDEN_LINT_GROUPS},
FutureIncompatibilityReason, Level, Lint, LintId,
};
use rustc_session::Session;
use rustc_span::hygiene::MacroKind;
use rustc_span::source_map::{DesugaringKind, ExpnKind};
use rustc_span::{symbol, Span, Symbol, DUMMY_SP};
use crate::ty::TyCtxt;
#[derive(Clone, Copy, PartialEq, Eq, HashStable, Debug)]
pub enum LintLevelSource {
Default,
Node {
name: Symbol,
span: Span,
reason: Option<Symbol>,
},
CommandLine(Symbol, Level),
}
impl LintLevelSource {
pub fn name(&self) -> Symbol {
match *self {
LintLevelSource::Default => symbol::kw::Default,
LintLevelSource::Node { name, .. } => name,
LintLevelSource::CommandLine(name, _) => name,
}
}
pub fn span(&self) -> Span {
match *self {
LintLevelSource::Default => DUMMY_SP,
LintLevelSource::Node { span, .. } => span,
LintLevelSource::CommandLine(_, _) => DUMMY_SP,
}
}
}
pub type LevelAndSource = (Level, LintLevelSource);
#[derive(Default, Debug, HashStable)]
pub struct ShallowLintLevelMap {
pub specs: SortedMap<ItemLocalId, FxHashMap<LintId, LevelAndSource>>,
}
pub fn reveal_actual_level(
level: Option<Level>,
src: &mut LintLevelSource,
sess: &Session,
lint: LintId,
probe_for_lint_level: impl FnOnce(LintId) -> (Option<Level>, LintLevelSource),
) -> Level {
let mut level = level.unwrap_or_else(|| lint.lint.default_level(sess.edition()));
if level == Level::Warn && lint != LintId::of(FORBIDDEN_LINT_GROUPS) {
let (warnings_level, warnings_src) = probe_for_lint_level(LintId::of(builtin::WARNINGS));
if let Some(configured_warning_level) = warnings_level {
if configured_warning_level != Level::Warn {
level = configured_warning_level;
*src = warnings_src;
}
}
}
level = if let LintLevelSource::CommandLine(_, Level::ForceWarn(_)) = src {
level
} else {
cmp::min(level, sess.opts.lint_cap.unwrap_or(Level::Forbid))
};
if let Some(driver_level) = sess.driver_lint_caps.get(&lint) {
level = cmp::min(*driver_level, level);
}
level
}
impl ShallowLintLevelMap {
#[instrument(level = "trace", skip(self, tcx), ret)]
fn probe_for_lint_level(
&self,
tcx: TyCtxt<'_>,
id: LintId,
start: HirId,
) -> (Option<Level>, LintLevelSource) {
if let Some(map) = self.specs.get(&start.local_id)
&& let Some(&(level, src)) = map.get(&id)
{
return (Some(level), src);
}
let mut owner = start.owner;
let mut specs = &self.specs;
for parent in tcx.hir().parent_id_iter(start) {
if parent.owner != owner {
owner = parent.owner;
specs = &tcx.shallow_lint_levels_on(owner).specs;
}
if let Some(map) = specs.get(&parent.local_id)
&& let Some(&(level, src)) = map.get(&id)
{
return (Some(level), src);
}
}
(None, LintLevelSource::Default)
}
#[instrument(level = "trace", skip(self, tcx), ret)]
pub fn lint_level_id_at_node(
&self,
tcx: TyCtxt<'_>,
lint: LintId,
cur: HirId,
) -> (Level, LintLevelSource) {
let (level, mut src) = self.probe_for_lint_level(tcx, lint, cur);
let level = reveal_actual_level(level, &mut src, tcx.sess, lint, |lint| {
self.probe_for_lint_level(tcx, lint, cur)
});
(level, src)
}
}
impl TyCtxt<'_> {
pub fn lint_level_at_node(self, lint: &'static Lint, id: HirId) -> (Level, LintLevelSource) {
self.shallow_lint_levels_on(id.owner).lint_level_id_at_node(self, LintId::of(lint), id)
}
pub fn maybe_lint_level_root_bounded(self, mut id: HirId, bound: HirId) -> HirId {
let hir = self.hir();
loop {
if id == bound {
return bound;
}
if hir.attrs(id).iter().any(|attr| Level::from_attr(attr).is_some()) {
return id;
}
let next = hir.get_parent_node(id);
if next == id {
bug!("lint traversal reached the root of the crate");
}
id = next;
}
}
}
#[derive(Clone, Debug, HashStable)]
pub struct LintExpectation {
pub reason: Option<Symbol>,
pub emission_span: Span,
pub is_unfulfilled_lint_expectations: bool,
pub lint_tool: Option<Symbol>,
}
impl LintExpectation {
pub fn new(
reason: Option<Symbol>,
emission_span: Span,
is_unfulfilled_lint_expectations: bool,
lint_tool: Option<Symbol>,
) -> Self {
Self { reason, emission_span, is_unfulfilled_lint_expectations, lint_tool }
}
}
pub fn explain_lint_level_source(
lint: &'static Lint,
level: Level,
src: LintLevelSource,
err: &mut Diagnostic,
) {
let name = lint.name_lower();
match src {
LintLevelSource::Default => {
err.note_once(&format!("`#[{}({})]` on by default", level.as_str(), name));
}
LintLevelSource::CommandLine(lint_flag_val, orig_level) => {
let flag = match orig_level {
Level::Warn => "-W",
Level::Deny => "-D",
Level::Forbid => "-F",
Level::Allow => "-A",
Level::ForceWarn(_) => "--force-warn",
Level::Expect(_) => {
unreachable!("the expect level does not have a commandline flag")
}
};
let hyphen_case_lint_name = name.replace('_', "-");
if lint_flag_val.as_str() == name {
err.note_once(&format!(
"requested on the command line with `{} {}`",
flag, hyphen_case_lint_name
));
} else {
let hyphen_case_flag_val = lint_flag_val.as_str().replace('_', "-");
err.note_once(&format!(
"`{} {}` implied by `{} {}`",
flag, hyphen_case_lint_name, flag, hyphen_case_flag_val
));
}
}
LintLevelSource::Node { name: lint_attr_name, span, reason, .. } => {
if let Some(rationale) = reason {
err.note(rationale.as_str());
}
err.span_note_once(span, "the lint level is defined here");
if lint_attr_name.as_str() != name {
let level_str = level.as_str();
err.note_once(&format!(
"`#[{}({})]` implied by `#[{}({})]`",
level_str, name, level_str, lint_attr_name
));
}
}
}
}
pub fn struct_lint_level(
sess: &Session,
lint: &'static Lint,
level: Level,
src: LintLevelSource,
span: Option<MultiSpan>,
msg: impl Into<DiagnosticMessage>,
decorate: impl for<'a, 'b> FnOnce(
&'b mut DiagnosticBuilder<'a, ()>,
) -> &'b mut DiagnosticBuilder<'a, ()>,
) {
fn struct_lint_level_impl(
sess: &Session,
lint: &'static Lint,
level: Level,
src: LintLevelSource,
span: Option<MultiSpan>,
msg: impl Into<DiagnosticMessage>,
decorate: Box<
dyn '_
+ for<'a, 'b> FnOnce(
&'b mut DiagnosticBuilder<'a, ()>,
) -> &'b mut DiagnosticBuilder<'a, ()>,
>,
) {
let future_incompatible = lint.future_incompatible;
let has_future_breakage = future_incompatible.map_or(
sess.opts.unstable_opts.future_incompat_test && lint.default_level != Level::Allow,
|incompat| {
matches!(incompat.reason, FutureIncompatibilityReason::FutureReleaseErrorReportNow)
},
);
let mut err = match (level, span) {
(Level::Allow, span) => {
if has_future_breakage {
if let Some(span) = span {
sess.struct_span_allow(span, "")
} else {
sess.struct_allow("")
}
} else {
return;
}
}
(Level::Expect(expect_id), _) => {
sess.struct_expect("", expect_id)
}
(Level::ForceWarn(Some(expect_id)), Some(span)) => {
sess.struct_span_warn_with_expectation(span, "", expect_id)
}
(Level::ForceWarn(Some(expect_id)), None) => {
sess.struct_warn_with_expectation("", expect_id)
}
(Level::Warn | Level::ForceWarn(None), Some(span)) => sess.struct_span_warn(span, ""),
(Level::Warn | Level::ForceWarn(None), None) => sess.struct_warn(""),
(Level::Deny | Level::Forbid, Some(span)) => {
let mut builder = sess.diagnostic().struct_err_lint("");
builder.set_span(span);
builder
}
(Level::Deny | Level::Forbid, None) => sess.diagnostic().struct_err_lint(""),
};
err.set_is_lint();
if err.span.primary_spans().iter().any(|s| in_external_macro(sess, *s)) {
err.disable_suggestions();
let not_future_incompatible =
future_incompatible.map(|f| f.reason.edition().is_some()).unwrap_or(true);
if not_future_incompatible && !lint.report_in_external_macro {
err.cancel();
return;
}
}
err.set_primary_message(msg);
if let Level::Expect(_) = level {
let name = lint.name_lower();
err.code(DiagnosticId::Lint { name, has_future_breakage, is_force_warn: false });
decorate(&mut err);
err.emit();
return;
}
let name = lint.name_lower();
let is_force_warn = matches!(level, Level::ForceWarn(_));
err.code(DiagnosticId::Lint { name, has_future_breakage, is_force_warn });
if let Some(future_incompatible) = future_incompatible {
let explanation = match future_incompatible.reason {
FutureIncompatibilityReason::FutureReleaseError
| FutureIncompatibilityReason::FutureReleaseErrorReportNow => {
"this was previously accepted by the compiler but is being phased out; \
it will become a hard error in a future release!"
.to_owned()
}
FutureIncompatibilityReason::FutureReleaseSemanticsChange => {
"this will change its meaning in a future release!".to_owned()
}
FutureIncompatibilityReason::EditionError(edition) => {
let current_edition = sess.edition();
format!(
"this is accepted in the current edition (Rust {}) but is a hard error in Rust {}!",
current_edition, edition
)
}
FutureIncompatibilityReason::EditionSemanticsChange(edition) => {
format!("this changes meaning in Rust {}", edition)
}
FutureIncompatibilityReason::Custom(reason) => reason.to_owned(),
};
if future_incompatible.explain_reason {
err.warn(&explanation);
}
if !future_incompatible.reference.is_empty() {
let citation =
format!("for more information, see {}", future_incompatible.reference);
err.note(&citation);
}
}
decorate(&mut err);
explain_lint_level_source(lint, level, src, &mut *err);
err.emit()
}
struct_lint_level_impl(sess, lint, level, src, span, msg, Box::new(decorate))
}
pub fn in_external_macro(sess: &Session, span: Span) -> bool {
let expn_data = span.ctxt().outer_expn_data();
match expn_data.kind {
ExpnKind::Inlined
| ExpnKind::Root
| ExpnKind::Desugaring(
DesugaringKind::ForLoop | DesugaringKind::WhileLoop | DesugaringKind::OpaqueTy,
) => false,
ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) => true, ExpnKind::Macro(MacroKind::Bang, _) => {
expn_data.def_site.is_dummy() || sess.source_map().is_imported(expn_data.def_site)
}
ExpnKind::Macro { .. } => true, }
}