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Commit 8365ad1

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handle opaque types before region inference
1 parent e255a9b commit 8365ad1

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45 files changed

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-1236
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45 files changed

+1094
-1236
lines changed

‎compiler/rustc_borrowck/src/dataflow.rs‎

Lines changed: 2 additions & 42 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,6 @@
11
use std::fmt;
22

33
use rustc_data_structures::fx::FxIndexMap;
4-
use rustc_data_structures::graph;
54
use rustc_index::bit_set::{DenseBitSet, MixedBitSet};
65
use rustc_middle::mir::{
76
self, BasicBlock, Body, CallReturnPlaces, Location, Place, TerminatorEdges,
@@ -317,9 +316,8 @@ impl<'tcx> PoloniusOutOfScopePrecomputer<'_, 'tcx> {
317316
loans_out_of_scope_at_location: FxIndexMap::default(),
318317
};
319318
for (loan_idx, loan_data) in borrow_set.iter_enumerated() {
320-
let issuing_region = loan_data.region;
321319
let loan_issued_at = loan_data.reserve_location;
322-
prec.precompute_loans_out_of_scope(loan_idx, issuing_region,loan_issued_at);
320+
prec.precompute_loans_out_of_scope(loan_idx, loan_issued_at);
323321
}
324322

325323
prec.loans_out_of_scope_at_location
@@ -328,45 +326,7 @@ impl<'tcx> PoloniusOutOfScopePrecomputer<'_, 'tcx> {
328326
/// Loans are in scope while they are live: whether they are contained within any live region.
329327
/// In the location-insensitive analysis, a loan will be contained in a region if the issuing
330328
/// region can reach it in the subset graph. So this is a reachability problem.
331-
fn precompute_loans_out_of_scope(
332-
&mut self,
333-
loan_idx: BorrowIndex,
334-
issuing_region: RegionVid,
335-
loan_issued_at: Location,
336-
) {
337-
let sccs = self.regioncx.constraint_sccs();
338-
let universal_regions = self.regioncx.universal_regions();
339-
340-
// The loop below was useful for the location-insensitive analysis but shouldn't be
341-
// impactful in the location-sensitive case. It seems that it does, however, as without it a
342-
// handful of tests fail. That likely means some liveness or outlives data related to choice
343-
// regions is missing
344-
// FIXME: investigate the impact of loans traversing applied member constraints and why some
345-
// tests fail otherwise.
346-
//
347-
// We first handle the cases where the loan doesn't go out of scope, depending on the
348-
// issuing region's successors.
349-
for successor in graph::depth_first_search(&self.regioncx.region_graph(), issuing_region) {
350-
// Via applied member constraints
351-
//
352-
// The issuing region can flow into the choice regions, and they are either:
353-
// - placeholders or free regions themselves,
354-
// - or also transitively outlive a free region.
355-
//
356-
// That is to say, if there are applied member constraints here, the loan escapes the
357-
// function and cannot go out of scope. We could early return here.
358-
//
359-
// For additional insurance via fuzzing and crater, we verify that the constraint's min
360-
// choice indeed escapes the function. In the future, we could e.g. turn this check into
361-
// a debug assert and early return as an optimization.
362-
let scc = sccs.scc(successor);
363-
for constraint in self.regioncx.applied_member_constraints(scc) {
364-
if universal_regions.is_universal_region(constraint.min_choice) {
365-
return;
366-
}
367-
}
368-
}
369-
329+
fn precompute_loans_out_of_scope(&mut self, loan_idx: BorrowIndex, loan_issued_at: Location) {
370330
let first_block = loan_issued_at.block;
371331
let first_bb_data = &self.body.basic_blocks[first_block];
372332

‎compiler/rustc_borrowck/src/diagnostics/opaque_types.rs‎

Lines changed: 52 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -13,6 +13,8 @@ use rustc_middle::mir::{self, ConstraintCategory, Location};
1313
use rustc_middle::ty::{
1414
self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor,
1515
};
16+
use rustc_span::Span;
17+
use rustc_trait_selection::error_reporting::infer::region::unexpected_hidden_region_diagnostic;
1618
use rustc_trait_selection::errors::impl_trait_overcapture_suggestion;
1719

1820
use crate::MirBorrowckCtxt;
@@ -26,13 +28,61 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
2628
if errors.is_empty() {
2729
return;
2830
}
31+
32+
let infcx = self.infcx;
2933
let mut guar = None;
34+
let mut last_unexpected_hidden_region: Option<(Span, Ty<'_>, ty::OpaqueTypeKey<'tcx>)> =
35+
None;
3036
for error in errors {
3137
guar = Some(match error {
32-
DeferredOpaqueTypeError::InvalidOpaqueTypeArgs(err) => err.report(self.infcx),
38+
DeferredOpaqueTypeError::InvalidOpaqueTypeArgs(err) => err.report(infcx),
3339
DeferredOpaqueTypeError::LifetimeMismatchOpaqueParam(err) => {
34-
self.infcx.dcx().emit_err(err)
40+
infcx.dcx().emit_err(err)
41+
}
42+
DeferredOpaqueTypeError::UnexpectedHiddenRegion {
43+
opaque_type_key,
44+
hidden_type,
45+
member_region,
46+
} => {
47+
let named_ty =
48+
self.regioncx.name_regions_for_member_constraint(infcx.tcx, hidden_type.ty);
49+
let named_key = self
50+
.regioncx
51+
.name_regions_for_member_constraint(infcx.tcx, opaque_type_key);
52+
let named_region =
53+
self.regioncx.name_regions_for_member_constraint(infcx.tcx, member_region);
54+
let diag = unexpected_hidden_region_diagnostic(
55+
infcx,
56+
self.mir_def_id(),
57+
hidden_type.span,
58+
named_ty,
59+
named_region,
60+
named_key,
61+
);
62+
if last_unexpected_hidden_region
63+
!= Some((hidden_type.span, named_ty, named_key))
64+
{
65+
last_unexpected_hidden_region =
66+
Some((hidden_type.span, named_ty, named_key));
67+
diag.emit()
68+
} else {
69+
diag.delay_as_bug()
70+
}
3571
}
72+
DeferredOpaqueTypeError::NonDefiningUseInDefiningScope {
73+
span,
74+
opaque_type_key,
75+
} => infcx.dcx().span_err(
76+
span,
77+
format!(
78+
"non-defining use of `{}` in the defining scope",
79+
Ty::new_opaque(
80+
infcx.tcx,
81+
opaque_type_key.def_id.to_def_id(),
82+
opaque_type_key.args
83+
)
84+
),
85+
),
3686
});
3787
}
3888
let guar = guar.unwrap();

‎compiler/rustc_borrowck/src/diagnostics/region_errors.rs‎

Lines changed: 0 additions & 41 deletions
Original file line numberDiff line numberDiff line change
@@ -23,7 +23,6 @@ use rustc_trait_selection::error_reporting::infer::nice_region_error::{
2323
self, HirTraitObjectVisitor, NiceRegionError, TraitObjectVisitor, find_anon_type,
2424
find_param_with_region, suggest_adding_lifetime_params,
2525
};
26-
use rustc_trait_selection::error_reporting::infer::region::unexpected_hidden_region_diagnostic;
2726
use rustc_trait_selection::infer::InferCtxtExt;
2827
use rustc_trait_selection::traits::{Obligation, ObligationCtxt};
2928
use tracing::{debug, instrument, trace};
@@ -105,18 +104,6 @@ pub(crate) enum RegionErrorKind<'tcx> {
105104
/// A generic bound failure for a type test (`T: 'a`).
106105
TypeTestError { type_test: TypeTest<'tcx> },
107106

108-
/// An unexpected hidden region for an opaque type.
109-
UnexpectedHiddenRegion {
110-
/// The span for the member constraint.
111-
span: Span,
112-
/// The hidden type.
113-
hidden_ty: Ty<'tcx>,
114-
/// The opaque type.
115-
key: ty::OpaqueTypeKey<'tcx>,
116-
/// The unexpected region.
117-
member_region: ty::Region<'tcx>,
118-
},
119-
120107
/// Higher-ranked subtyping error.
121108
BoundUniversalRegionError {
122109
/// The placeholder free region.
@@ -323,11 +310,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
323310
pub(crate) fn report_region_errors(&mut self, nll_errors: RegionErrors<'tcx>) {
324311
// Iterate through all the errors, producing a diagnostic for each one. The diagnostics are
325312
// buffered in the `MirBorrowckCtxt`.
326-
327313
let mut outlives_suggestion = OutlivesSuggestionBuilder::default();
328-
let mut last_unexpected_hidden_region: Option<(Span, Ty<'_>, ty::OpaqueTypeKey<'tcx>)> =
329-
None;
330-
331314
for (nll_error, _) in nll_errors.into_iter() {
332315
match nll_error {
333316
RegionErrorKind::TypeTestError { type_test } => {
@@ -378,30 +361,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
378361
}
379362
}
380363

381-
RegionErrorKind::UnexpectedHiddenRegion { span, hidden_ty, key, member_region } => {
382-
let named_ty =
383-
self.regioncx.name_regions_for_member_constraint(self.infcx.tcx, hidden_ty);
384-
let named_key =
385-
self.regioncx.name_regions_for_member_constraint(self.infcx.tcx, key);
386-
let named_region = self
387-
.regioncx
388-
.name_regions_for_member_constraint(self.infcx.tcx, member_region);
389-
let diag = unexpected_hidden_region_diagnostic(
390-
self.infcx,
391-
self.mir_def_id(),
392-
span,
393-
named_ty,
394-
named_region,
395-
named_key,
396-
);
397-
if last_unexpected_hidden_region != Some((span, named_ty, named_key)) {
398-
self.buffer_error(diag);
399-
last_unexpected_hidden_region = Some((span, named_ty, named_key));
400-
} else {
401-
diag.delay_as_bug();
402-
}
403-
}
404-
405364
RegionErrorKind::BoundUniversalRegionError {
406365
longer_fr,
407366
placeholder,

‎compiler/rustc_borrowck/src/handle_placeholders.rs‎

Lines changed: 4 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,6 @@ use tracing::debug;
1515
use crate::constraints::{ConstraintSccIndex, OutlivesConstraintSet};
1616
use crate::consumers::OutlivesConstraint;
1717
use crate::diagnostics::UniverseInfo;
18-
use crate::member_constraints::MemberConstraintSet;
1918
use crate::region_infer::values::{LivenessValues, PlaceholderIndices};
2019
use crate::region_infer::{ConstraintSccs, RegionDefinition, Representative, TypeTest};
2120
use crate::ty::VarianceDiagInfo;
@@ -30,7 +29,6 @@ pub(crate) struct LoweredConstraints<'tcx> {
3029
pub(crate) constraint_sccs: Sccs<RegionVid, ConstraintSccIndex>,
3130
pub(crate) definitions: Frozen<IndexVec<RegionVid, RegionDefinition<'tcx>>>,
3231
pub(crate) scc_annotations: IndexVec<ConstraintSccIndex, RegionTracker>,
33-
pub(crate) member_constraints: MemberConstraintSet<'tcx, RegionVid>,
3432
pub(crate) outlives_constraints: Frozen<OutlivesConstraintSet<'tcx>>,
3533
pub(crate) type_tests: Vec<TypeTest<'tcx>>,
3634
pub(crate) liveness_constraints: LivenessValues,
@@ -147,9 +145,10 @@ impl scc::Annotation for RegionTracker {
147145

148146
/// Determines if the region variable definitions contain
149147
/// placeholders, and compute them for later use.
150-
fnregion_definitions<'tcx>(
151-
universal_regions:&UniversalRegions<'tcx>,
148+
// FIXME: This is also used by opaque type handling. Move it to a separate file.
149+
pub(super)fnregion_definitions<'tcx>(
152150
infcx: &BorrowckInferCtxt<'tcx>,
151+
universal_regions: &UniversalRegions<'tcx>,
153152
) -> (Frozen<IndexVec<RegionVid, RegionDefinition<'tcx>>>, bool) {
154153
let var_infos = infcx.get_region_var_infos();
155154
// Create a RegionDefinition for each inference variable. This happens here because
@@ -213,14 +212,13 @@ pub(crate) fn compute_sccs_applying_placeholder_outlives_constraints<'tcx>(
213212
infcx: &BorrowckInferCtxt<'tcx>,
214213
) -> LoweredConstraints<'tcx> {
215214
let universal_regions = &universal_region_relations.universal_regions;
216-
let (definitions, has_placeholders) = region_definitions(universal_regions, infcx);
215+
let (definitions, has_placeholders) = region_definitions(infcx, universal_regions);
217216

218217
let MirTypeckRegionConstraints {
219218
placeholder_indices,
220219
placeholder_index_to_region: _,
221220
liveness_constraints,
222221
mut outlives_constraints,
223-
member_constraints,
224222
universe_causes,
225223
type_tests,
226224
} = constraints;
@@ -246,7 +244,6 @@ pub(crate) fn compute_sccs_applying_placeholder_outlives_constraints<'tcx>(
246244

247245
return LoweredConstraints {
248246
type_tests,
249-
member_constraints,
250247
constraint_sccs,
251248
scc_annotations: scc_annotations.scc_to_annotation,
252249
definitions,
@@ -283,7 +280,6 @@ pub(crate) fn compute_sccs_applying_placeholder_outlives_constraints<'tcx>(
283280
constraint_sccs,
284281
definitions,
285282
scc_annotations,
286-
member_constraints,
287283
outlives_constraints: Frozen::freeze(outlives_constraints),
288284
type_tests,
289285
liveness_constraints,

‎compiler/rustc_borrowck/src/lib.rs‎

Lines changed: 14 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -78,7 +78,6 @@ mod dataflow;
7878
mod def_use;
7979
mod diagnostics;
8080
mod handle_placeholders;
81-
mod member_constraints;
8281
mod nll;
8382
mod path_utils;
8483
mod place_ext;
@@ -335,9 +334,10 @@ fn do_mir_borrowck<'tcx>(
335334

336335
// Run the MIR type-checker.
337336
let MirTypeckResults {
338-
constraints,
337+
mutconstraints,
339338
universal_region_relations,
340-
opaque_type_values,
339+
region_bound_pairs,
340+
known_type_outlives_obligations,
341341
polonius_context,
342342
} = type_check::type_check(
343343
root_cx,
@@ -352,6 +352,17 @@ fn do_mir_borrowck<'tcx>(
352352
Rc::clone(&location_map),
353353
);
354354

355+
let opaque_type_errors = region_infer::opaque_types::handle_opaque_type_uses(
356+
root_cx,
357+
&infcx,
358+
&body,
359+
&universal_region_relations,
360+
&region_bound_pairs,
361+
&known_type_outlives_obligations,
362+
&location_map,
363+
&mut constraints,
364+
);
365+
355366
// Compute non-lexical lifetimes using the constraints computed
356367
// by typechecking the MIR body.
357368
let nll::NllOutput {
@@ -375,8 +386,6 @@ fn do_mir_borrowck<'tcx>(
375386
polonius_context,
376387
);
377388

378-
let opaque_type_errors = regioncx.infer_opaque_types(root_cx, &infcx, opaque_type_values);
379-
380389
// Dump MIR results into a file, if that is enabled. This lets us
381390
// write unit-tests, as well as helping with debugging.
382391
nll::dump_nll_mir(&infcx, body, &regioncx, &opt_closure_req, &borrow_set);

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