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Remove good_path_delayed_bug.

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It's only has a single remaining purpose: to ensure that a diagnostic is
printed when `trimmed_def_paths` is used. It's an annoying mechanism:
weak, with odd semantics, badly named, and gets in the way of other
changes.

This commit replaces it with a simpler `must_produce_diag` mechanism,
getting rid of a diagnostic `Level` along the way.
This commit is contained in:
Nicholas Nethercote 2024-02-12 16:48:45 +11:00
parent 173dbc9e13
commit 9f2aa09765
9 changed files with 56 additions and 119 deletions
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106
compiler/rustc_errors/src/lib.rs
View file

@ -435,7 +435,6 @@ struct DiagCtxtInner {
lint_err_guars: Vec<ErrorGuaranteed>,
/// The delayed bugs and their error guarantees.
delayed_bugs: Vec<(DelayedDiagnostic, ErrorGuaranteed)>,
good_path_delayed_bugs: Vec<DelayedDiagnostic>,
/// The number of stashed errors. Unlike the other counts, this can go up
/// and down, so it doesn't guarantee anything.
@ -446,13 +445,18 @@ struct DiagCtxtInner {
/// The warning count shown to the user at the end.
deduplicated_warn_count: usize,
emitter: Box<DynEmitter>,
/// Must we produce a diagnostic to justify the use of the expensive
/// `trimmed_def_paths` function?
must_produce_diag: bool,
/// Has this diagnostic context printed any diagnostics? (I.e. has
/// `self.emitter.emit_diagnostic()` been called?
has_printed: bool,
emitter: Box<DynEmitter>,
/// This flag indicates that an expected diagnostic was emitted and suppressed.
/// This is used for the `good_path_delayed_bugs` check.
/// This is used for the `must_produce_diag` check.
suppressed_expected_diag: bool,
/// This set contains the code of all emitted diagnostics to avoid
@ -533,11 +537,6 @@ fn default_track_diagnostic(diag: Diagnostic, f: &mut dyn FnMut(Diagnostic)) {
pub static TRACK_DIAGNOSTIC: AtomicRef<fn(Diagnostic, &mut dyn FnMut(Diagnostic))> =
AtomicRef::new(&(default_track_diagnostic as _));
enum DelayedBugKind {
Normal,
GoodPath,
}
#[derive(Copy, Clone, Default)]
pub struct DiagCtxtFlags {
/// If false, warning-level lints are suppressed.
@ -563,11 +562,16 @@ impl Drop for DiagCtxtInner {
self.emit_stashed_diagnostics();
if self.err_guars.is_empty() {
self.flush_delayed(DelayedBugKind::Normal)
self.flush_delayed()
}
if !self.has_printed && !self.suppressed_expected_diag && !std::thread::panicking() {
self.flush_delayed(DelayedBugKind::GoodPath);
if self.must_produce_diag {
panic!(
"must_produce_diag: trimmed_def_paths called but no diagnostics emitted; \
use `DelayDm` for lints or `with_no_trimmed_paths` for debugging"
);
}
}
if self.check_unstable_expect_diagnostics {
@ -609,12 +613,12 @@ impl DiagCtxt {
err_guars: Vec::new(),
lint_err_guars: Vec::new(),
delayed_bugs: Vec::new(),
good_path_delayed_bugs: Vec::new(),
stashed_err_count: 0,
deduplicated_err_count: 0,
deduplicated_warn_count: 0,
has_printed: false,
emitter,
must_produce_diag: false,
has_printed: false,
suppressed_expected_diag: false,
taught_diagnostics: Default::default(),
emitted_diagnostic_codes: Default::default(),
@ -666,13 +670,14 @@ impl DiagCtxt {
inner.stashed_err_count = 0;
inner.deduplicated_err_count = 0;
inner.deduplicated_warn_count = 0;
inner.must_produce_diag = false;
inner.has_printed = false;
inner.suppressed_expected_diag = false;
// actually free the underlying memory (which `clear` would not do)
inner.err_guars = Default::default();
inner.lint_err_guars = Default::default();
inner.delayed_bugs = Default::default();
inner.good_path_delayed_bugs = Default::default();
inner.taught_diagnostics = Default::default();
inner.emitted_diagnostic_codes = Default::default();
inner.emitted_diagnostics = Default::default();
@ -934,7 +939,13 @@ impl DiagCtxt {
}
pub fn flush_delayed(&self) {
self.inner.borrow_mut().flush_delayed(DelayedBugKind::Normal);
self.inner.borrow_mut().flush_delayed();
}
/// Used when trimmed_def_paths is called and we must produce a diagnostic
/// to justify its cost.
pub fn set_must_produce_diag(&self) {
self.inner.borrow_mut().must_produce_diag = true;
}
}
@ -1108,13 +1119,6 @@ impl DiagCtxt {
DiagnosticBuilder::<ErrorGuaranteed>::new(self, DelayedBug, msg).with_span(sp).emit()
}
/// Ensures that a diagnostic is printed. See `Level::GoodPathDelayedBug`.
// No `#[rustc_lint_diagnostics]` because bug messages aren't user-facing.
#[track_caller]
pub fn good_path_delayed_bug(&self, msg: impl Into<DiagnosticMessage>) {
DiagnosticBuilder::<()>::new(self, GoodPathDelayedBug, msg).emit()
}
#[rustc_lint_diagnostics]
#[track_caller]
pub fn struct_warn(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_, ()> {
@ -1266,19 +1270,17 @@ impl DiagCtxtInner {
if diagnostic.has_future_breakage() {
// Future breakages aren't emitted if they're Level::Allow,
// but they still need to be constructed and stashed below,
// so they'll trigger the good-path bug check.
// so they'll trigger the must_produce_diag check.
self.suppressed_expected_diag = true;
self.future_breakage_diagnostics.push(diagnostic.clone());
}
if matches!(diagnostic.level, DelayedBug | GoodPathDelayedBug)
&& self.flags.eagerly_emit_delayed_bugs
{
if diagnostic.level == DelayedBug && self.flags.eagerly_emit_delayed_bugs {
diagnostic.level = Error;
}
match diagnostic.level {
// This must come after the possible promotion of `DelayedBug`/`GoodPathDelayedBug` to
// This must come after the possible promotion of `DelayedBug` to
// `Error` above.
Fatal | Error if self.treat_next_err_as_bug() => {
diagnostic.level = Bug;
@ -1297,12 +1299,6 @@ impl DiagCtxtInner {
.push((DelayedDiagnostic::with_backtrace(diagnostic, backtrace), guar));
return Some(guar);
}
GoodPathDelayedBug => {
let backtrace = std::backtrace::Backtrace::capture();
self.good_path_delayed_bugs
.push(DelayedDiagnostic::with_backtrace(diagnostic, backtrace));
return None;
}
Warning if !self.flags.can_emit_warnings => {
if diagnostic.has_future_breakage() {
(*TRACK_DIAGNOSTIC)(diagnostic, &mut |_| {});
@ -1414,23 +1410,14 @@ impl DiagCtxtInner {
self.emit_diagnostic(Diagnostic::new(FailureNote, msg));
}
fn flush_delayed(&mut self, kind: DelayedBugKind) {
let (bugs, note1) = match kind {
DelayedBugKind::Normal => (
std::mem::take(&mut self.delayed_bugs).into_iter().map(|(b, _)| b).collect(),
"no errors encountered even though delayed bugs were created",
),
DelayedBugKind::GoodPath => (
std::mem::take(&mut self.good_path_delayed_bugs),
"no warnings or errors encountered even though good path delayed bugs were created",
),
};
let note2 = "those delayed bugs will now be shown as internal compiler errors";
if bugs.is_empty() {
fn flush_delayed(&mut self) {
if self.delayed_bugs.is_empty() {
return;
}
let bugs: Vec<_> =
std::mem::take(&mut self.delayed_bugs).into_iter().map(|(b, _)| b).collect();
// If backtraces are enabled, also print the query stack
let backtrace = std::env::var_os("RUST_BACKTRACE").map_or(true, |x| &x != "0");
for (i, bug) in bugs.into_iter().enumerate() {
@ -1454,6 +1441,8 @@ impl DiagCtxtInner {
// frame them better (e.g. separate warnings from them). Also,
// make it a note so it doesn't count as an error, because that
// could trigger `-Ztreat-err-as-bug`, which we don't want.
let note1 = "no errors encountered even though delayed bugs were created";
let note2 = "those delayed bugs will now be shown as internal compiler errors";
self.emit_diagnostic(Diagnostic::new(Note, note1));
self.emit_diagnostic(Diagnostic::new(Note, note2));
}
@ -1462,7 +1451,7 @@ impl DiagCtxtInner {
if backtrace || self.ice_file.is_none() { bug.decorate() } else { bug.inner };
// "Undelay" the delayed bugs (into plain `Bug`s).
if !matches!(bug.level, DelayedBug | GoodPathDelayedBug) {
if bug.level != DelayedBug {
// NOTE(eddyb) not panicking here because we're already producing
// an ICE, and the more information the merrier.
bug.subdiagnostic(InvalidFlushedDelayedDiagnosticLevel {
@ -1534,7 +1523,6 @@ impl DelayedDiagnostic {
/// Fatal yes FatalAbort/FatalError(*) yes - -
/// Error yes ErrorGuaranteed yes - yes
/// DelayedBug yes ErrorGuaranteed yes - -
/// GoodPathDelayedBug - () yes - -
/// ForceWarning - () yes - lint-only
/// Warning - () yes yes yes
/// Note - () rare yes -
@ -1567,20 +1555,6 @@ pub enum Level {
/// that should only be reached when compiling erroneous code.
DelayedBug,
/// Like `DelayedBug`, but weaker: lets you register an error without emitting it. If
/// compilation ends without any other diagnostics being emitted (and without an expected lint
/// being suppressed), this will be emitted as a bug. Otherwise, it will be silently dropped.
/// I.e. "expect other diagnostics are emitted (or suppressed)" semantics. Useful on code paths
/// that should only be reached when emitting diagnostics, e.g. for expensive one-time
/// diagnostic formatting operations.
///
/// FIXME(nnethercote) good path delayed bugs are semantically strange: if printed they produce
/// an ICE, but they don't satisfy `is_error` and they don't guarantee an error is emitted.
/// Plus there's the extra complication with expected (suppressed) lints. They have limited
/// use, and are used in very few places, and "good path" isn't a good name. It would be good
/// to remove them.
GoodPathDelayedBug,
/// A `force-warn` lint warning about the code being compiled. Does not prevent compilation
/// from finishing.
///
@ -1625,7 +1599,7 @@ impl Level {
fn color(self) -> ColorSpec {
let mut spec = ColorSpec::new();
match self {
Bug | Fatal | Error | DelayedBug | GoodPathDelayedBug => {
Bug | Fatal | Error | DelayedBug => {
spec.set_fg(Some(Color::Red)).set_intense(true);
}
ForceWarning(_) | Warning => {
@ -1645,7 +1619,7 @@ impl Level {
pub fn to_str(self) -> &'static str {
match self {
Bug | DelayedBug | GoodPathDelayedBug => "error: internal compiler error",
Bug | DelayedBug => "error: internal compiler error",
Fatal | Error => "error",
ForceWarning(_) | Warning => "warning",
Note | OnceNote => "note",
@ -1670,8 +1644,8 @@ impl Level {
// subdiagnostic message?
fn can_be_top_or_sub(&self) -> (bool, bool) {
match self {
Bug | DelayedBug | Fatal | Error | GoodPathDelayedBug | ForceWarning(_)
| FailureNote | Allow | Expect(_) => (true, false),
Bug | DelayedBug | Fatal | Error | ForceWarning(_) | FailureNote | Allow
| Expect(_) => (true, false),
Warning | Note | Help => (true, true),