diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs index 8e5944d6cf4..2d993a3fd16 100644 --- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs +++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs @@ -1516,15 +1516,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { }); self.explain_why_borrow_contains_point(location, borrow, None) - .add_explanation_to_diagnostic( - self.infcx.tcx, - self.body, - &self.local_names, - &mut err, - "", - Some(borrow_span), - None, - ); + .add_explanation_to_diagnostic(&self, &mut err, "", Some(borrow_span), None); self.suggest_copy_for_type_in_cloned_ref(&mut err, place); let typeck_results = self.infcx.tcx.typeck(self.mir_def_id()); 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) - .add_explanation_to_diagnostic( - self.infcx.tcx, - self.body, - &self.local_names, - &mut err, - "", - None, - None, - ); + .add_explanation_to_diagnostic(&self, &mut err, "", None, None); err } @@ -1886,9 +1870,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { } explanation.add_explanation_to_diagnostic( - self.infcx.tcx, - self.body, - &self.local_names, + &self, &mut err, first_borrow_desc, None, @@ -3046,15 +3028,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { if let BorrowExplanation::MustBeValidFor { .. } = explanation { } else { - explanation.add_explanation_to_diagnostic( - self.infcx.tcx, - self.body, - &self.local_names, - &mut err, - "", - None, - None, - ); + explanation.add_explanation_to_diagnostic(&self, &mut err, "", None, None); } } else { 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( - self.infcx.tcx, - self.body, - &self.local_names, - &mut err, - "", - Some(borrow_span), - None, - ); + explanation.add_explanation_to_diagnostic(&self, &mut err, "", Some(borrow_span), None); } err @@ -3128,15 +3094,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { _ => {} } - explanation.add_explanation_to_diagnostic( - self.infcx.tcx, - self.body, - &self.local_names, - &mut err, - "", - None, - None, - ); + explanation.add_explanation_to_diagnostic(&self, &mut err, "", None, None); self.buffer_error(err); } @@ -3309,15 +3267,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { } _ => {} } - explanation.add_explanation_to_diagnostic( - self.infcx.tcx, - self.body, - &self.local_names, - &mut err, - "", - None, - None, - ); + explanation.add_explanation_to_diagnostic(&self, &mut err, "", None, None); borrow_spans.args_subdiag(&mut err, |args_span| { 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.infcx.tcx, - self.body, - &self.local_names, - &mut err, - "", - None, - None, - ); + self.explain_why_borrow_contains_point(location, loan, None) + .add_explanation_to_diagnostic(&self, &mut err, "", None, None); self.explain_deref_coercion(loan, &mut err); diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs index 87017460e8e..860d6338a02 100644 --- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs +++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs @@ -8,7 +8,6 @@ use std::assert_matches::assert_matches; use rustc_errors::{Applicability, Diag}; use rustc_hir as hir; use rustc_hir::intravisit::Visitor; -use rustc_index::IndexSlice; use rustc_infer::infer::NllRegionVariableOrigin; use rustc_middle::middle::resolve_bound_vars::ObjectLifetimeDefault; use rustc_middle::mir::{ @@ -18,14 +17,15 @@ use rustc_middle::mir::{ use rustc_middle::ty::adjustment::PointerCoercion; use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt}; 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 tracing::{debug, instrument}; use super::{RegionName, UseSpans, find_use}; use crate::borrow_set::BorrowData; +use crate::constraints::OutlivesConstraint; use crate::nll::ConstraintDescription; -use crate::region_infer::{BlameConstraint, Cause, ExtraConstraintInfo}; +use crate::region_infer::{BlameConstraint, Cause}; use crate::{MirBorrowckCtxt, WriteKind}; #[derive(Debug)] @@ -43,7 +43,7 @@ pub(crate) enum BorrowExplanation<'tcx> { span: Span, region_name: RegionName, opt_place_desc: Option, - extra_info: Vec, + path: Vec>, }, Unexplained, } @@ -63,14 +63,16 @@ impl<'tcx> BorrowExplanation<'tcx> { } pub(crate) fn add_explanation_to_diagnostic( &self, - tcx: TyCtxt<'tcx>, - body: &Body<'tcx>, - local_names: &IndexSlice>, + cx: &MirBorrowckCtxt<'_, '_, 'tcx>, err: &mut Diag<'_>, borrow_desc: &str, borrow_span: Option, 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 { let def_id = body.source.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 opt_place_desc, from_closure: _, - ref extra_info, + ref path, } => { region_name.highlight_region_name(err); @@ -328,13 +330,7 @@ impl<'tcx> BorrowExplanation<'tcx> { ); }; - for extra in extra_info { - match extra { - ExtraConstraintInfo::PlaceholderFromPredicate(span) => { - err.span_note(*span, "due to current limitations in the borrow checker, this implies a `'static` lifetime"); - } - } - } + cx.add_placeholder_from_predicate_note(err, &path); if let ConstraintCategory::Cast { is_implicit_coercion: true, @@ -487,8 +483,9 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> { &self, borrow_region: RegionVid, outlived_region: RegionVid, - ) -> (ConstraintCategory<'tcx>, bool, Span, Option, Vec) { - let (blame_constraint, extra_info) = self.regioncx.best_blame_constraint( + ) -> (ConstraintCategory<'tcx>, bool, Span, Option, Vec>) + { + let (blame_constraint, path) = self.regioncx.best_blame_constraint( borrow_region, NllRegionVariableOrigin::FreeRegion, |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); - (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 @@ -596,7 +593,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> { None => { 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); if let Some(region_name) = region_name { let opt_place_desc = self.describe_place(borrow.borrowed_place.as_ref()); @@ -606,7 +603,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> { span, region_name, opt_place_desc, - extra_info, + path, } } else { debug!("Could not generate a region name"); diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs index ebbdfea302c..c9100f23e12 100644 --- a/compiler/rustc_borrowck/src/diagnostics/mod.rs +++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs @@ -8,14 +8,16 @@ use rustc_errors::{Applicability, Diag, MultiSpan}; use rustc_hir::def::{CtorKind, Namespace}; use rustc_hir::{self as hir, CoroutineKind, LangItem}; use rustc_index::IndexSlice; -use rustc_infer::infer::BoundRegionConversionTime; +use rustc_infer::infer::{ + BoundRegionConversionTime, NllRegionVariableOrigin, RegionVariableOrigin, +}; use rustc_infer::traits::SelectionError; use rustc_middle::bug; use rustc_middle::mir::tcx::PlaceTy; use rustc_middle::mir::{ - AggregateKind, CallSource, ConstOperand, FakeReadCause, Local, LocalInfo, LocalKind, Location, - Operand, Place, PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator, - TerminatorKind, + AggregateKind, CallSource, ConstOperand, ConstraintCategory, FakeReadCause, Local, LocalInfo, + LocalKind, Location, Operand, Place, PlaceRef, ProjectionElem, Rvalue, Statement, + StatementKind, Terminator, TerminatorKind, }; use rustc_middle::ty::print::Print; use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; @@ -33,6 +35,7 @@ use tracing::debug; use super::MirBorrowckCtxt; use super::borrow_set::BorrowData; +use crate::constraints::OutlivesConstraint; use crate::fluent_generated as fluent; use crate::session_diagnostics::{ CaptureArgLabel, CaptureReasonLabel, CaptureReasonNote, CaptureReasonSuggest, CaptureVarCause, @@ -619,6 +622,31 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { region.print(&mut printer).unwrap(); 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. diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs index 3555009c63f..481b8d41f10 100644 --- a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs +++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs @@ -29,7 +29,7 @@ use tracing::{debug, instrument, trace}; use super::{OutlivesSuggestionBuilder, RegionName, RegionNameSource}; use crate::nll::ConstraintDescription; use crate::region_infer::values::RegionElement; -use crate::region_infer::{BlameConstraint, ExtraConstraintInfo, TypeTest}; +use crate::region_infer::{BlameConstraint, TypeTest}; use crate::session_diagnostics::{ FnMutError, FnMutReturnTypeErr, GenericDoesNotLiveLongEnough, LifetimeOutliveErr, LifetimeReturnCategoryErr, RequireStaticErr, VarHereDenote, @@ -440,10 +440,9 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { ) { debug!("report_region_error(fr={:?}, outlived_fr={:?})", fr, outlived_fr); - let (blame_constraint, extra_info) = - self.regioncx.best_blame_constraint(fr, fr_origin, |r| { - self.regioncx.provides_universal_region(r, fr, outlived_fr) - }); + let (blame_constraint, path) = self.regioncx.best_blame_constraint(fr, fr_origin, |r| { + self.regioncx.provides_universal_region(r, fr, outlived_fr) + }); let BlameConstraint { category, cause, variance_info, .. } = blame_constraint; debug!("report_region_error: category={:?} {:?} {:?}", category, cause, variance_info); @@ -554,13 +553,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { } } - for extra in extra_info { - match extra { - ExtraConstraintInfo::PlaceholderFromPredicate(span) => { - diag.span_note(span, "due to current limitations in the borrow checker, this implies a `'static` lifetime"); - } - } - } + self.add_placeholder_from_predicate_note(&mut diag, &path); self.buffer_error(diag); } diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs index 2150759d329..b49fa463a4f 100644 --- a/compiler/rustc_borrowck/src/region_infer/mod.rs +++ b/compiler/rustc_borrowck/src/region_infer/mod.rs @@ -315,11 +315,6 @@ enum Trace<'tcx> { NotVisited, } -#[derive(Clone, PartialEq, Eq, Debug)] -pub(crate) enum ExtraConstraintInfo { - PlaceholderFromPredicate(Span), -} - #[instrument(skip(infcx, sccs), level = "debug")] fn sccs_info<'tcx>(infcx: &BorrowckInferCtxt<'tcx>, sccs: &ConstraintSccs) { use crate::renumber::RegionCtxt; @@ -1948,7 +1943,7 @@ impl<'tcx> RegionInferenceContext<'tcx> { from_region: RegionVid, from_region_origin: NllRegionVariableOrigin, target_test: impl Fn(RegionVid) -> bool, - ) -> (BlameConstraint<'tcx>, Vec) { + ) -> (BlameConstraint<'tcx>, Vec>) { // Find all paths let (path, target_region) = self .find_constraint_paths_between_regions(from_region, target_test) @@ -1970,25 +1965,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { .collect::>() ); - 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. // Instead, we use it to produce an improved `ObligationCauseCode`. // FIXME - determine what we should do if we encounter multiple @@ -2115,7 +2091,7 @@ impl<'tcx> RegionInferenceContext<'tcx> { let best_choice = 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(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 // 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 @@ -2154,7 +2130,7 @@ impl<'tcx> RegionInferenceContext<'tcx> { categorized_path.sort_by_key(|p| p.category); 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> {