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rework borrowck errors so that it's harder to not set tainted
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compiler-errors committed Feb 11, 2022
1 parent 8b7b0a0 commit 29c2bb5
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Showing 7 changed files with 119 additions and 74 deletions.
2 changes: 1 addition & 1 deletion compiler/rustc_borrowck/src/borrowck_errors.rs
Original file line number Diff line number Diff line change
Expand Up @@ -327,7 +327,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
verb: &str,
optional_adverb_for_moved: &str,
moved_path: Option<String>,
) -> DiagnosticBuilder<'cx> {
) -> DiagnosticBuilder<'tcx> {
let moved_path = moved_path.map(|mp| format!(": `{}`", mp)).unwrap_or_default();

struct_span_err!(
Expand Down
14 changes: 2 additions & 12 deletions compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
if move_out_indices.is_empty() {
let root_place = PlaceRef { projection: &[], ..used_place };

self.set_tainted_by_errors();
if !self.uninitialized_error_reported.insert(root_place) {
debug!(
"report_use_of_moved_or_uninitialized place: error about {:?} suppressed",
Expand Down Expand Up @@ -107,7 +106,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {

self.buffer_error(err);
} else {
if let Some((reported_place, _)) = self.move_error_reported.get(&move_out_indices) {
if let Some((reported_place, _)) = self.has_move_error(&move_out_indices) {
if self.prefixes(*reported_place, PrefixSet::All).any(|p| p == used_place) {
debug!(
"report_use_of_moved_or_uninitialized place: error suppressed \
Expand Down Expand Up @@ -217,7 +216,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
place_name, partially_str, loop_message
),
);
self.set_tainted_by_errors();
if self.fn_self_span_reported.insert(fn_span) {
err.span_note(
// Check whether the source is accessible
Expand Down Expand Up @@ -299,7 +297,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
}
// Avoid pointing to the same function in multiple different
// error messages.
self.set_tainted_by_errors();
if span != DUMMY_SP && self.fn_self_span_reported.insert(self_arg.span)
{
err.span_note(
Expand Down Expand Up @@ -452,13 +449,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
}
}

self.set_tainted_by_errors();
if let Some((_, mut old_err)) =
self.move_error_reported.insert(move_out_indices, (used_place, err))
{
// Cancel the old error so it doesn't ICE.
old_err.cancel();
}
self.buffer_move_error(move_out_indices, (used_place, err));
}
}

Expand Down Expand Up @@ -1016,7 +1007,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
return;
}

self.set_tainted_by_errors();
self.access_place_error_reported.insert((
Place { local: root_place.local, projection: root_place_projection },
borrow_span,
Expand Down
159 changes: 107 additions & 52 deletions compiler/rustc_borrowck/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -175,10 +175,13 @@ fn do_mir_borrowck<'a, 'tcx>(
}
}

let mut errors = error::BorrowckErrors::new();

// Gather the upvars of a closure, if any.
let tables = tcx.typeck_opt_const_arg(def);
if let Some(ErrorReported) = tables.tainted_by_errors {
infcx.set_tainted_by_errors();
errors.set_tainted_by_errors();
}
let upvars: Vec<_> = tables
.closure_min_captures_flattened(def.did.to_def_id())
Expand All @@ -205,7 +208,6 @@ fn do_mir_borrowck<'a, 'tcx>(
let location_table_owned = LocationTable::new(body);
let location_table = &location_table_owned;

let mut errors_buffer = Vec::new();
let (move_data, move_errors): (MoveData<'tcx>, Vec<(Place<'tcx>, MoveError<'tcx>)>) =
match MoveData::gather_moves(&body, tcx, param_env) {
Ok(move_data) => (move_data, Vec::new()),
Expand Down Expand Up @@ -263,7 +265,7 @@ fn do_mir_borrowck<'a, 'tcx>(
&regioncx,
&opt_closure_req,
&opaque_type_values,
&mut errors_buffer,
&mut errors,
);

// The various `flow_*` structures can be large. We drop `flow_inits` here
Expand Down Expand Up @@ -310,10 +312,7 @@ fn do_mir_borrowck<'a, 'tcx>(
access_place_error_reported: Default::default(),
reservation_error_reported: Default::default(),
reservation_warnings: Default::default(),
move_error_reported: BTreeMap::new(),
uninitialized_error_reported: Default::default(),
errors_buffer,
tainted_by_errors: false,
regioncx: regioncx.clone(),
used_mut: Default::default(),
used_mut_upvars: SmallVec::new(),
Expand All @@ -324,9 +323,10 @@ fn do_mir_borrowck<'a, 'tcx>(
region_names: RefCell::default(),
next_region_name: RefCell::new(1),
polonius_output: None,
errors,
};
promoted_mbcx.report_move_errors(move_errors);
errors_buffer = promoted_mbcx.errors_buffer;
errors = promoted_mbcx.errors;
};
}

Expand All @@ -344,10 +344,7 @@ fn do_mir_borrowck<'a, 'tcx>(
access_place_error_reported: Default::default(),
reservation_error_reported: Default::default(),
reservation_warnings: Default::default(),
move_error_reported: BTreeMap::new(),
uninitialized_error_reported: Default::default(),
errors_buffer,
tainted_by_errors: false,
regioncx: Rc::clone(&regioncx),
used_mut: Default::default(),
used_mut_upvars: SmallVec::new(),
Expand All @@ -358,6 +355,7 @@ fn do_mir_borrowck<'a, 'tcx>(
region_names: RefCell::default(),
next_region_name: RefCell::new(1),
polonius_output,
errors,
};

// Compute and report region errors, if any.
Expand Down Expand Up @@ -462,24 +460,13 @@ fn do_mir_borrowck<'a, 'tcx>(
})
}

// Buffer any move errors that we collected and de-duplicated.
for (_, (_, diag)) in std::mem::take(&mut mbcx.move_error_reported) {
mbcx.buffer_error(diag);
}

if !mbcx.errors_buffer.is_empty() {
mbcx.errors_buffer.sort_by_key(|diag| diag.sort_span);

for diag in mbcx.errors_buffer.drain(..) {
mbcx.infcx.tcx.sess.diagnostic().emit_diagnostic(&diag);
}
}
let tainted_by_errors = mbcx.emit_errors();

let result = BorrowCheckResult {
concrete_opaque_types: opaque_type_values,
closure_requirements: opt_closure_req,
used_mut_upvars: mbcx.used_mut_upvars,
tainted_by_errors: mbcx.tainted_by_errors,
tainted_by_errors,
};

let body_with_facts = if return_body_with_facts {
Expand Down Expand Up @@ -556,28 +543,9 @@ struct MirBorrowckCtxt<'cx, 'tcx> {
/// for the activation of the borrow.
reservation_warnings:
FxHashMap<BorrowIndex, (Place<'tcx>, Span, Location, BorrowKind, BorrowData<'tcx>)>,
/// This field keeps track of move errors that are to be reported for given move indices.
///
/// There are situations where many errors can be reported for a single move out (see #53807)
/// and we want only the best of those errors.
///
/// The `report_use_of_moved_or_uninitialized` function checks this map and replaces the
/// diagnostic (if there is one) if the `Place` of the error being reported is a prefix of the
/// `Place` of the previous most diagnostic. This happens instead of buffering the error. Once
/// all move errors have been reported, any diagnostics in this map are added to the buffer
/// to be emitted.
///
/// `BTreeMap` is used to preserve the order of insertions when iterating. This is necessary
/// when errors in the map are being re-added to the error buffer so that errors with the
/// same primary span come out in a consistent order.
move_error_reported: BTreeMap<Vec<MoveOutIndex>, (PlaceRef<'tcx>, DiagnosticBuilder<'cx>)>,
/// This field keeps track of errors reported in the checking of uninitialized variables,
/// so that we don't report seemingly duplicate errors.
uninitialized_error_reported: FxHashSet<PlaceRef<'tcx>>,
/// Errors to be reported buffer
errors_buffer: Vec<Diagnostic>,
/// Set to true if we emit an error during borrowck
tainted_by_errors: bool,
/// This field keeps track of all the local variables that are declared mut and are mutated.
/// Used for the warning issued by an unused mutable local variable.
used_mut: FxHashSet<Local>,
Expand Down Expand Up @@ -609,6 +577,8 @@ struct MirBorrowckCtxt<'cx, 'tcx> {

/// Results of Polonius analysis.
polonius_output: Option<Rc<PoloniusOutput>>,

errors: error::BorrowckErrors<'tcx>,
}

// Check that:
Expand Down Expand Up @@ -1032,8 +1002,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {

if conflict_error || mutability_error {
debug!("access_place: logging error place_span=`{:?}` kind=`{:?}`", place_span, kind);

self.set_tainted_by_errors();
self.access_place_error_reported.insert((place_span.0, place_span.1));
}
}
Expand Down Expand Up @@ -2055,10 +2023,9 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
| WriteKind::MutableBorrow(BorrowKind::Shared)
| WriteKind::MutableBorrow(BorrowKind::Shallow),
) => {
if let (Err(_), true) = (
self.is_mutable(place.as_ref(), is_local_mutation_allowed),
self.errors_buffer.is_empty(),
) {
if self.is_mutable(place.as_ref(), is_local_mutation_allowed).is_err()
&& !self.has_buffered_errors()
{
// rust-lang/rust#46908: In pure NLL mode this code path should be
// unreachable, but we use `delay_span_bug` because we can hit this when
// dereferencing a non-Copy raw pointer *and* have `-Ztreat-err-as-bug`
Expand Down Expand Up @@ -2308,14 +2275,102 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
fn is_upvar_field_projection(&self, place_ref: PlaceRef<'tcx>) -> Option<Field> {
path_utils::is_upvar_field_projection(self.infcx.tcx, &self.upvars, place_ref, self.body())
}
}

mod error {
use super::*;

pub struct BorrowckErrors<'tcx> {
/// This field keeps track of move errors that are to be reported for given move indices.
///
/// There are situations where many errors can be reported for a single move out (see #53807)
/// and we want only the best of those errors.
///
/// The `report_use_of_moved_or_uninitialized` function checks this map and replaces the
/// diagnostic (if there is one) if the `Place` of the error being reported is a prefix of the
/// `Place` of the previous most diagnostic. This happens instead of buffering the error. Once
/// all move errors have been reported, any diagnostics in this map are added to the buffer
/// to be emitted.
///
/// `BTreeMap` is used to preserve the order of insertions when iterating. This is necessary
/// when errors in the map are being re-added to the error buffer so that errors with the
/// same primary span come out in a consistent order.
buffered_move_errors:
BTreeMap<Vec<MoveOutIndex>, (PlaceRef<'tcx>, DiagnosticBuilder<'tcx>)>,
/// Errors to be reported buffer
buffered: Vec<Diagnostic>,
/// Set to Some if we emit an error during borrowck
tainted_by_errors: Option<ErrorReported>,
}

impl BorrowckErrors<'_> {
pub fn new() -> Self {
BorrowckErrors {
buffered_move_errors: BTreeMap::new(),
buffered: Default::default(),
tainted_by_errors: None,
}
}

pub fn buffer_error(&mut self, t: DiagnosticBuilder<'_>) {
self.tainted_by_errors = Some(ErrorReported {});
t.buffer(&mut self.buffered);
}

pub fn buffer_error(&mut self, t: DiagnosticBuilder<'_>) {
self.tainted_by_errors = true;
t.buffer(&mut self.errors_buffer);
pub fn set_tainted_by_errors(&mut self) {
self.tainted_by_errors = Some(ErrorReported {});
}
}

pub fn set_tainted_by_errors(&mut self) {
self.tainted_by_errors = true;
impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
pub fn buffer_error(&mut self, t: DiagnosticBuilder<'_>) {
self.errors.buffer_error(t);
}

pub fn buffer_move_error(
&mut self,
move_out_indices: Vec<MoveOutIndex>,
place_and_err: (PlaceRef<'tcx>, DiagnosticBuilder<'tcx>),
) -> bool {
if let Some((_, mut diag)) =
self.errors.buffered_move_errors.insert(move_out_indices, place_and_err)
{
// Cancel the old diagnostic so we don't ICE
diag.cancel();
false
} else {
true
}
}

pub fn emit_errors(&mut self) -> Option<ErrorReported> {
// Buffer any move errors that we collected and de-duplicated.
for (_, (_, diag)) in std::mem::take(&mut self.errors.buffered_move_errors) {
// We have already set tainted for this error, so just buffer it.
diag.buffer(&mut self.errors.buffered);
}

if !self.errors.buffered.is_empty() {
self.errors.buffered.sort_by_key(|diag| diag.sort_span);

for diag in self.errors.buffered.drain(..) {
self.infcx.tcx.sess.diagnostic().emit_diagnostic(&diag);
}
}

self.errors.tainted_by_errors
}

pub fn has_buffered_errors(&self) -> bool {
self.errors.buffered.is_empty()
}

pub fn has_move_error(
&self,
move_out_indices: &[MoveOutIndex],
) -> Option<&(PlaceRef<'tcx>, DiagnosticBuilder<'cx>)> {
self.errors.buffered_move_errors.get(move_out_indices)
}
}
}

Expand Down
6 changes: 2 additions & 4 deletions compiler/rustc_borrowck/src/nll.rs
Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
//! The entry point of the NLL borrow checker.
use rustc_data_structures::vec_map::VecMap;
use rustc_errors::Diagnostic;
use rustc_index::vec::IndexVec;
use rustc_infer::infer::InferCtxt;
use rustc_middle::mir::{create_dump_file, dump_enabled, dump_mir, PassWhere};
Expand Down Expand Up @@ -373,7 +372,7 @@ pub(super) fn dump_annotation<'a, 'tcx>(
regioncx: &RegionInferenceContext<'tcx>,
closure_region_requirements: &Option<ClosureRegionRequirements<'_>>,
opaque_type_values: &VecMap<OpaqueTypeKey<'tcx>, Ty<'tcx>>,
errors_buffer: &mut Vec<Diagnostic>,
errors: &mut crate::error::BorrowckErrors<'tcx>,
) {
let tcx = infcx.tcx;
let base_def_id = tcx.typeck_root_def_id(body.source.def_id());
Expand Down Expand Up @@ -418,8 +417,7 @@ pub(super) fn dump_annotation<'a, 'tcx>(
err.note(&format!("Inferred opaque type values:\n{:#?}", opaque_type_values));
}

// FIXME(compiler-errors): Maybe we need to set tainted here
err.buffer(errors_buffer);
errors.buffer_error(err);
}

fn for_each_region_constraint(
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_const_eval/src/const_eval/eval_queries.rs
Original file line number Diff line number Diff line change
Expand Up @@ -287,8 +287,8 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
if let Some(error_reported) = tcx.typeck_opt_const_arg(def).tainted_by_errors {
return Err(ErrorHandled::Reported(error_reported));
}
if tcx.mir_borrowck_opt_const_arg(def).tainted_by_errors {
return Err(ErrorHandled::Reported(ErrorReported {}));
if let Some(error_reported) = tcx.mir_borrowck_opt_const_arg(def).tainted_by_errors {
return Err(ErrorHandled::Reported(error_reported));
}
}
if !tcx.is_mir_available(def.did) {
Expand Down
6 changes: 4 additions & 2 deletions compiler/rustc_const_eval/src/interpret/eval_context.rs
Original file line number Diff line number Diff line change
Expand Up @@ -516,8 +516,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
if let Some(error_reported) = self.tcx.typeck_opt_const_arg(def).tainted_by_errors {
throw_inval!(AlreadyReported(error_reported));
}
if self.tcx.mir_borrowck_opt_const_arg(def).tainted_by_errors {
throw_inval!(AlreadyReported(rustc_errors::ErrorReported {}));
if let Some(error_reported) =
self.tcx.mir_borrowck_opt_const_arg(def).tainted_by_errors
{
throw_inval!(AlreadyReported(error_reported));
}
}
}
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_middle/src/mir/query.rs
Original file line number Diff line number Diff line change
Expand Up @@ -214,7 +214,7 @@ pub struct BorrowCheckResult<'tcx> {
pub concrete_opaque_types: VecMap<OpaqueTypeKey<'tcx>, Ty<'tcx>>,
pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
pub used_mut_upvars: SmallVec<[Field; 8]>,
pub tainted_by_errors: bool,
pub tainted_by_errors: Option<ErrorReported>,
}

/// The result of the `mir_const_qualif` query.
Expand Down

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