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cleanup: remove ExtraConstraintInfo

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`ExtraConstraintInfo` was used only for a single subdiagnostic, so this moves the logic for that
to its own function and eliminates the indirection. In order to do so cleanly, this also changes
the arguments to `BorrowExplanation::add_explanation_to_diagnostic`, which happens to simplify its
call sites.
This commit is contained in:
dianne 2024-12-12 01:20:26 -08:00
parent 243d2ca4db
commit aa8d5bff4c
5 changed files with 68 additions and 131 deletions
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75
compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
View file

@ -1516,15 +1516,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
}); });
self.explain_why_borrow_contains_point(location, borrow, None) self.explain_why_borrow_contains_point(location, borrow, None)
.add_explanation_to_diagnostic( .add_explanation_to_diagnostic(&self, &mut err, "", Some(borrow_span), None);
self.infcx.tcx,
self.body,
&self.local_names,
&mut err,
"",
Some(borrow_span),
None,
);
self.suggest_copy_for_type_in_cloned_ref(&mut err, place); self.suggest_copy_for_type_in_cloned_ref(&mut err, place);
let typeck_results = self.infcx.tcx.typeck(self.mir_def_id()); let typeck_results = self.infcx.tcx.typeck(self.mir_def_id());
if let Some(expr) = self.find_expr(borrow_span) { if let Some(expr) = self.find_expr(borrow_span) {
@ -1591,15 +1583,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
}); });
self.explain_why_borrow_contains_point(location, borrow, None) self.explain_why_borrow_contains_point(location, borrow, None)
.add_explanation_to_diagnostic( .add_explanation_to_diagnostic(&self, &mut err, "", None, None);
self.infcx.tcx,
self.body,
&self.local_names,
&mut err,
"",
None,
None,
);
err err
} }
@ -1886,9 +1870,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
} }
explanation.add_explanation_to_diagnostic( explanation.add_explanation_to_diagnostic(
self.infcx.tcx, &self,
self.body,
&self.local_names,
&mut err, &mut err,
first_borrow_desc, first_borrow_desc,
None, None,
@ -3046,15 +3028,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
if let BorrowExplanation::MustBeValidFor { .. } = explanation { if let BorrowExplanation::MustBeValidFor { .. } = explanation {
} else { } else {
explanation.add_explanation_to_diagnostic( explanation.add_explanation_to_diagnostic(&self, &mut err, "", None, None);
self.infcx.tcx,
self.body,
&self.local_names,
&mut err,
"",
None,
None,
);
} }
} else { } else {
err.span_label(borrow_span, "borrowed value does not live long enough"); err.span_label(borrow_span, "borrowed value does not live long enough");
@ -3067,15 +3041,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
} }
}); });
explanation.add_explanation_to_diagnostic( explanation.add_explanation_to_diagnostic(&self, &mut err, "", Some(borrow_span), None);
self.infcx.tcx,
self.body,
&self.local_names,
&mut err,
"",
Some(borrow_span),
None,
);
} }
err err
@ -3128,15 +3094,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
_ => {} _ => {}
} }
explanation.add_explanation_to_diagnostic( explanation.add_explanation_to_diagnostic(&self, &mut err, "", None, None);
self.infcx.tcx,
self.body,
&self.local_names,
&mut err,
"",
None,
None,
);
self.buffer_error(err); self.buffer_error(err);
} }
@ -3309,15 +3267,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
} }
_ => {} _ => {}
} }
explanation.add_explanation_to_diagnostic( explanation.add_explanation_to_diagnostic(&self, &mut err, "", None, None);
self.infcx.tcx,
self.body,
&self.local_names,
&mut err,
"",
None,
None,
);
borrow_spans.args_subdiag(&mut err, |args_span| { borrow_spans.args_subdiag(&mut err, |args_span| {
crate::session_diagnostics::CaptureArgLabel::Capture { crate::session_diagnostics::CaptureArgLabel::Capture {
@ -3808,15 +3758,8 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
} }
}); });
self.explain_why_borrow_contains_point(location, loan, None).add_explanation_to_diagnostic( self.explain_why_borrow_contains_point(location, loan, None)
self.infcx.tcx, .add_explanation_to_diagnostic(&self, &mut err, "", None, None);
self.body,
&self.local_names,
&mut err,
"",
None,
None,
);
self.explain_deref_coercion(loan, &mut err); self.explain_deref_coercion(loan, &mut err);

37
compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
View file

@ -8,7 +8,6 @@ use std::assert_matches::assert_matches;
use rustc_errors::{Applicability, Diag}; use rustc_errors::{Applicability, Diag};
use rustc_hir as hir; use rustc_hir as hir;
use rustc_hir::intravisit::Visitor; use rustc_hir::intravisit::Visitor;
use rustc_index::IndexSlice;
use rustc_infer::infer::NllRegionVariableOrigin; use rustc_infer::infer::NllRegionVariableOrigin;
use rustc_middle::middle::resolve_bound_vars::ObjectLifetimeDefault; use rustc_middle::middle::resolve_bound_vars::ObjectLifetimeDefault;
use rustc_middle::mir::{ use rustc_middle::mir::{
@ -18,14 +17,15 @@ use rustc_middle::mir::{
use rustc_middle::ty::adjustment::PointerCoercion; use rustc_middle::ty::adjustment::PointerCoercion;
use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt}; use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt};
use rustc_middle::util::CallKind; use rustc_middle::util::CallKind;
use rustc_span::{DesugaringKind, Span, Symbol, kw, sym}; use rustc_span::{DesugaringKind, Span, kw, sym};
use rustc_trait_selection::error_reporting::traits::FindExprBySpan; use rustc_trait_selection::error_reporting::traits::FindExprBySpan;
use tracing::{debug, instrument}; use tracing::{debug, instrument};
use super::{RegionName, UseSpans, find_use}; use super::{RegionName, UseSpans, find_use};
use crate::borrow_set::BorrowData; use crate::borrow_set::BorrowData;
use crate::constraints::OutlivesConstraint;
use crate::nll::ConstraintDescription; use crate::nll::ConstraintDescription;
use crate::region_infer::{BlameConstraint, Cause, ExtraConstraintInfo}; use crate::region_infer::{BlameConstraint, Cause};
use crate::{MirBorrowckCtxt, WriteKind}; use crate::{MirBorrowckCtxt, WriteKind};
#[derive(Debug)] #[derive(Debug)]
@ -43,7 +43,7 @@ pub(crate) enum BorrowExplanation<'tcx> {
span: Span, span: Span,
region_name: RegionName, region_name: RegionName,
opt_place_desc: Option<String>, opt_place_desc: Option<String>,
extra_info: Vec<ExtraConstraintInfo>, path: Vec<OutlivesConstraint<'tcx>>,
}, },
Unexplained, Unexplained,
} }
@ -63,14 +63,16 @@ impl<'tcx> BorrowExplanation<'tcx> {
} }
pub(crate) fn add_explanation_to_diagnostic( pub(crate) fn add_explanation_to_diagnostic(
&self, &self,
tcx: TyCtxt<'tcx>, cx: &MirBorrowckCtxt<'_, '_, 'tcx>,
body: &Body<'tcx>,
local_names: &IndexSlice<Local, Option<Symbol>>,
err: &mut Diag<'_>, err: &mut Diag<'_>,
borrow_desc: &str, borrow_desc: &str,
borrow_span: Option<Span>, borrow_span: Option<Span>,
multiple_borrow_span: Option<(Span, Span)>, multiple_borrow_span: Option<(Span, Span)>,
) { ) {
let tcx = cx.infcx.tcx;
let body = cx.body;
let local_names = &cx.local_names;
if let Some(span) = borrow_span { if let Some(span) = borrow_span {
let def_id = body.source.def_id(); let def_id = body.source.def_id();
if let Some(node) = tcx.hir().get_if_local(def_id) if let Some(node) = tcx.hir().get_if_local(def_id)
@ -306,7 +308,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
ref region_name, ref region_name,
ref opt_place_desc, ref opt_place_desc,
from_closure: _, from_closure: _,
ref extra_info, ref path,
} => { } => {
region_name.highlight_region_name(err); region_name.highlight_region_name(err);
@ -328,13 +330,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
); );
}; };
for extra in extra_info { cx.add_placeholder_from_predicate_note(err, &path);
match extra {
ExtraConstraintInfo::PlaceholderFromPredicate(span) => {
err.span_note(*span, "due to current limitations in the borrow checker, this implies a `'static` lifetime");
}
}
}
if let ConstraintCategory::Cast { if let ConstraintCategory::Cast {
is_implicit_coercion: true, is_implicit_coercion: true,
@ -487,8 +483,9 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
&self, &self,
borrow_region: RegionVid, borrow_region: RegionVid,
outlived_region: RegionVid, outlived_region: RegionVid,
) -> (ConstraintCategory<'tcx>, bool, Span, Option<RegionName>, Vec<ExtraConstraintInfo>) { ) -> (ConstraintCategory<'tcx>, bool, Span, Option<RegionName>, Vec<OutlivesConstraint<'tcx>>)
let (blame_constraint, extra_info) = self.regioncx.best_blame_constraint( {
let (blame_constraint, path) = self.regioncx.best_blame_constraint(
borrow_region, borrow_region,
NllRegionVariableOrigin::FreeRegion, NllRegionVariableOrigin::FreeRegion,
|r| self.regioncx.provides_universal_region(r, borrow_region, outlived_region), |r| self.regioncx.provides_universal_region(r, borrow_region, outlived_region),
@ -497,7 +494,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
let outlived_fr_name = self.give_region_a_name(outlived_region); let outlived_fr_name = self.give_region_a_name(outlived_region);
(category, from_closure, cause.span, outlived_fr_name, extra_info) (category, from_closure, cause.span, outlived_fr_name, path)
} }
/// Returns structured explanation for *why* the borrow contains the /// Returns structured explanation for *why* the borrow contains the
@ -596,7 +593,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
None => { None => {
if let Some(region) = self.to_error_region_vid(borrow_region_vid) { if let Some(region) = self.to_error_region_vid(borrow_region_vid) {
let (category, from_closure, span, region_name, extra_info) = let (category, from_closure, span, region_name, path) =
self.free_region_constraint_info(borrow_region_vid, region); self.free_region_constraint_info(borrow_region_vid, region);
if let Some(region_name) = region_name { if let Some(region_name) = region_name {
let opt_place_desc = self.describe_place(borrow.borrowed_place.as_ref()); let opt_place_desc = self.describe_place(borrow.borrowed_place.as_ref());
@ -606,7 +603,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
span, span,
region_name, region_name,
opt_place_desc, opt_place_desc,
extra_info, path,
} }
} else { } else {
debug!("Could not generate a region name"); debug!("Could not generate a region name");

36
compiler/rustc_borrowck/src/diagnostics/mod.rs
View file

@ -8,14 +8,16 @@ use rustc_errors::{Applicability, Diag, MultiSpan};
use rustc_hir::def::{CtorKind, Namespace}; use rustc_hir::def::{CtorKind, Namespace};
use rustc_hir::{self as hir, CoroutineKind, LangItem}; use rustc_hir::{self as hir, CoroutineKind, LangItem};
use rustc_index::IndexSlice; use rustc_index::IndexSlice;
use rustc_infer::infer::BoundRegionConversionTime; use rustc_infer::infer::{
BoundRegionConversionTime, NllRegionVariableOrigin, RegionVariableOrigin,
};
use rustc_infer::traits::SelectionError; use rustc_infer::traits::SelectionError;
use rustc_middle::bug; use rustc_middle::bug;
use rustc_middle::mir::tcx::PlaceTy; use rustc_middle::mir::tcx::PlaceTy;
use rustc_middle::mir::{ use rustc_middle::mir::{
AggregateKind, CallSource, ConstOperand, FakeReadCause, Local, LocalInfo, LocalKind, Location, AggregateKind, CallSource, ConstOperand, ConstraintCategory, FakeReadCause, Local, LocalInfo,
Operand, Place, PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator, LocalKind, Location, Operand, Place, PlaceRef, ProjectionElem, Rvalue, Statement,
TerminatorKind, StatementKind, Terminator, TerminatorKind,
}; };
use rustc_middle::ty::print::Print; use rustc_middle::ty::print::Print;
use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
@ -33,6 +35,7 @@ use tracing::debug;
use super::MirBorrowckCtxt; use super::MirBorrowckCtxt;
use super::borrow_set::BorrowData; use super::borrow_set::BorrowData;
use crate::constraints::OutlivesConstraint;
use crate::fluent_generated as fluent; use crate::fluent_generated as fluent;
use crate::session_diagnostics::{ use crate::session_diagnostics::{
CaptureArgLabel, CaptureReasonLabel, CaptureReasonNote, CaptureReasonSuggest, CaptureVarCause, CaptureArgLabel, CaptureReasonLabel, CaptureReasonNote, CaptureReasonSuggest, CaptureVarCause,
@ -619,6 +622,31 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
region.print(&mut printer).unwrap(); region.print(&mut printer).unwrap();
printer.into_buffer() printer.into_buffer()
} }
/// Add a note to region errors and borrow explanations when higher-ranked regions in predicates
/// implicitly introduce an "outlives `'static`" constraint.
fn add_placeholder_from_predicate_note(
&self,
err: &mut Diag<'_>,
path: &[OutlivesConstraint<'tcx>],
) {
let predicate_span = path.iter().find_map(|constraint| {
let outlived = constraint.sub;
if let Some(origin) = self.regioncx.var_infos.get(outlived)
&& let RegionVariableOrigin::Nll(NllRegionVariableOrigin::Placeholder(_)) =
origin.origin
&& let ConstraintCategory::Predicate(span) = constraint.category
{
Some(span)
} else {
None
}
});
if let Some(span) = predicate_span {
err.span_note(span, "due to current limitations in the borrow checker, this implies a `'static` lifetime");
}
}
} }
/// The span(s) associated to a use of a place. /// The span(s) associated to a use of a place.

17
compiler/rustc_borrowck/src/diagnostics/region_errors.rs
View file

@ -29,7 +29,7 @@ use tracing::{debug, instrument, trace};
use super::{OutlivesSuggestionBuilder, RegionName, RegionNameSource}; use super::{OutlivesSuggestionBuilder, RegionName, RegionNameSource};
use crate::nll::ConstraintDescription; use crate::nll::ConstraintDescription;
use crate::region_infer::values::RegionElement; use crate::region_infer::values::RegionElement;
use crate::region_infer::{BlameConstraint, ExtraConstraintInfo, TypeTest}; use crate::region_infer::{BlameConstraint, TypeTest};
use crate::session_diagnostics::{ use crate::session_diagnostics::{
FnMutError, FnMutReturnTypeErr, GenericDoesNotLiveLongEnough, LifetimeOutliveErr, FnMutError, FnMutReturnTypeErr, GenericDoesNotLiveLongEnough, LifetimeOutliveErr,
LifetimeReturnCategoryErr, RequireStaticErr, VarHereDenote, LifetimeReturnCategoryErr, RequireStaticErr, VarHereDenote,
@ -440,10 +440,9 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
) { ) {
debug!("report_region_error(fr={:?}, outlived_fr={:?})", fr, outlived_fr); debug!("report_region_error(fr={:?}, outlived_fr={:?})", fr, outlived_fr);
let (blame_constraint, extra_info) = let (blame_constraint, path) = self.regioncx.best_blame_constraint(fr, fr_origin, |r| {
self.regioncx.best_blame_constraint(fr, fr_origin, |r| { self.regioncx.provides_universal_region(r, fr, outlived_fr)
self.regioncx.provides_universal_region(r, fr, outlived_fr) });
});
let BlameConstraint { category, cause, variance_info, .. } = blame_constraint; let BlameConstraint { category, cause, variance_info, .. } = blame_constraint;
debug!("report_region_error: category={:?} {:?} {:?}", category, cause, variance_info); debug!("report_region_error: category={:?} {:?} {:?}", category, cause, variance_info);
@ -554,13 +553,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
} }
} }
for extra in extra_info { self.add_placeholder_from_predicate_note(&mut diag, &path);
match extra {
ExtraConstraintInfo::PlaceholderFromPredicate(span) => {
diag.span_note(span, "due to current limitations in the borrow checker, this implies a `'static` lifetime");
}
}
}
self.buffer_error(diag); self.buffer_error(diag);
} }

34
compiler/rustc_borrowck/src/region_infer/mod.rs
View file

@ -315,11 +315,6 @@ enum Trace<'tcx> {
NotVisited, NotVisited,
} }
#[derive(Clone, PartialEq, Eq, Debug)]
pub(crate) enum ExtraConstraintInfo {
PlaceholderFromPredicate(Span),
}
#[instrument(skip(infcx, sccs), level = "debug")] #[instrument(skip(infcx, sccs), level = "debug")]
fn sccs_info<'tcx>(infcx: &BorrowckInferCtxt<'tcx>, sccs: &ConstraintSccs) { fn sccs_info<'tcx>(infcx: &BorrowckInferCtxt<'tcx>, sccs: &ConstraintSccs) {
use crate::renumber::RegionCtxt; use crate::renumber::RegionCtxt;
@ -1948,7 +1943,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
from_region: RegionVid, from_region: RegionVid,
from_region_origin: NllRegionVariableOrigin, from_region_origin: NllRegionVariableOrigin,
target_test: impl Fn(RegionVid) -> bool, target_test: impl Fn(RegionVid) -> bool,
) -> (BlameConstraint<'tcx>, Vec<ExtraConstraintInfo>) { ) -> (BlameConstraint<'tcx>, Vec<OutlivesConstraint<'tcx>>) {
// Find all paths // Find all paths
let (path, target_region) = self let (path, target_region) = self
.find_constraint_paths_between_regions(from_region, target_test) .find_constraint_paths_between_regions(from_region, target_test)
@ -1970,25 +1965,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
.collect::<Vec<_>>() .collect::<Vec<_>>()
); );
let mut extra_info = vec![];
for constraint in path.iter() {
let outlived = constraint.sub;
let Some(origin) = self.var_infos.get(outlived) else {
continue;
};
let RegionVariableOrigin::Nll(NllRegionVariableOrigin::Placeholder(p)) = origin.origin
else {
continue;
};
debug!(?constraint, ?p);
let ConstraintCategory::Predicate(span) = constraint.category else {
continue;
};
extra_info.push(ExtraConstraintInfo::PlaceholderFromPredicate(span));
// We only want to point to one
break;
}
// We try to avoid reporting a `ConstraintCategory::Predicate` as our best constraint. // We try to avoid reporting a `ConstraintCategory::Predicate` as our best constraint.
// Instead, we use it to produce an improved `ObligationCauseCode`. // Instead, we use it to produce an improved `ObligationCauseCode`.
// FIXME - determine what we should do if we encounter multiple // FIXME - determine what we should do if we encounter multiple
@ -2115,7 +2091,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
let best_choice = let best_choice =
if blame_source { range.rev().find(find_region) } else { range.find(find_region) }; if blame_source { range.rev().find(find_region) } else { range.find(find_region) };
debug!(?best_choice, ?blame_source, ?extra_info); debug!(?best_choice, ?blame_source);
if let Some(i) = best_choice { if let Some(i) = best_choice {
if let Some(next) = categorized_path.get(i + 1) { if let Some(next) = categorized_path.get(i + 1) {
@ -2124,7 +2100,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
{ {
// The return expression is being influenced by the return type being // The return expression is being influenced by the return type being
// impl Trait, point at the return type and not the return expr. // impl Trait, point at the return type and not the return expr.
return (next.clone(), extra_info); return (next.clone(), path);
} }
} }
@ -2144,7 +2120,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
} }
} }
return (categorized_path[i].clone(), extra_info); return (categorized_path[i].clone(), path);
} }
// If that search fails, that is.. unusual. Maybe everything // If that search fails, that is.. unusual. Maybe everything
@ -2154,7 +2130,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
categorized_path.sort_by_key(|p| p.category); categorized_path.sort_by_key(|p| p.category);
debug!("sorted_path={:#?}", categorized_path); debug!("sorted_path={:#?}", categorized_path);
(categorized_path.remove(0), extra_info) (categorized_path.remove(0), path)
} }
pub(crate) fn universe_info(&self, universe: ty::UniverseIndex) -> UniverseInfo<'tcx> { pub(crate) fn universe_info(&self, universe: ty::UniverseIndex) -> UniverseInfo<'tcx> {