diff options
Diffstat (limited to '')
| -rw-r--r-- | compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs | 64 |
1 files changed, 34 insertions, 30 deletions
diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs index 72aee0267..1c01e78ab 100644 --- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs +++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs @@ -15,7 +15,7 @@ use rustc_middle::ty::{self, RegionVid, TyCtxt}; use rustc_span::symbol::{kw, Symbol}; use rustc_span::{sym, DesugaringKind, Span}; -use crate::region_infer::BlameConstraint; +use crate::region_infer::{BlameConstraint, ExtraConstraintInfo}; use crate::{ borrow_set::BorrowData, nll::ConstraintDescription, region_infer::Cause, MirBorrowckCtxt, WriteKind, @@ -38,6 +38,7 @@ pub(crate) enum BorrowExplanation<'tcx> { span: Span, region_name: RegionName, opt_place_desc: Option<String>, + extra_info: Vec<ExtraConstraintInfo>, }, Unexplained, } @@ -243,6 +244,7 @@ impl<'tcx> BorrowExplanation<'tcx> { ref region_name, ref opt_place_desc, from_closure: _, + ref extra_info, } => { region_name.highlight_region_name(err); @@ -268,18 +270,30 @@ impl<'tcx> BorrowExplanation<'tcx> { ); }; + for extra in extra_info { + match extra { + ExtraConstraintInfo::PlaceholderFromPredicate(span) => { + err.span_note(*span, format!("due to current limitations in the borrow checker, this implies a `'static` lifetime")); + } + } + } + self.add_lifetime_bound_suggestion_to_diagnostic(err, &category, span, region_name); } _ => {} } } - pub(crate) fn add_lifetime_bound_suggestion_to_diagnostic( + + fn add_lifetime_bound_suggestion_to_diagnostic( &self, err: &mut Diagnostic, category: &ConstraintCategory<'tcx>, span: Span, region_name: &RegionName, ) { + if !span.is_desugaring(DesugaringKind::OpaqueTy) { + return; + } if let ConstraintCategory::OpaqueType = category { let suggestable_name = if region_name.was_named() { region_name.name } else { kw::UnderscoreLifetime }; @@ -305,18 +319,17 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { &self, borrow_region: RegionVid, outlived_region: RegionVid, - ) -> (ConstraintCategory<'tcx>, bool, Span, Option<RegionName>) { - let BlameConstraint { category, from_closure, cause, variance_info: _ } = - self.regioncx.best_blame_constraint( - &self.body, - borrow_region, - NllRegionVariableOrigin::FreeRegion, - |r| self.regioncx.provides_universal_region(r, borrow_region, outlived_region), - ); + ) -> (ConstraintCategory<'tcx>, bool, Span, Option<RegionName>, Vec<ExtraConstraintInfo>) { + let (blame_constraint, extra_info) = self.regioncx.best_blame_constraint( + borrow_region, + NllRegionVariableOrigin::FreeRegion, + |r| self.regioncx.provides_universal_region(r, borrow_region, outlived_region), + ); + let BlameConstraint { category, from_closure, cause, .. } = blame_constraint; let outlived_fr_name = self.give_region_a_name(outlived_region); - (category, from_closure, cause.span, outlived_fr_name) + (category, from_closure, cause.span, outlived_fr_name, extra_info) } /// Returns structured explanation for *why* the borrow contains the @@ -332,26 +345,22 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { /// - second half is the place being accessed /// /// [d]: https://rust-lang.github.io/rfcs/2094-nll.html#leveraging-intuition-framing-errors-in-terms-of-points + #[instrument(level = "debug", skip(self))] pub(crate) fn explain_why_borrow_contains_point( &self, location: Location, borrow: &BorrowData<'tcx>, kind_place: Option<(WriteKind, Place<'tcx>)>, ) -> BorrowExplanation<'tcx> { - debug!( - "explain_why_borrow_contains_point(location={:?}, borrow={:?}, kind_place={:?})", - location, borrow, kind_place - ); - let regioncx = &self.regioncx; let body: &Body<'_> = &self.body; let tcx = self.infcx.tcx; let borrow_region_vid = borrow.region; - debug!("explain_why_borrow_contains_point: borrow_region_vid={:?}", borrow_region_vid); + debug!(?borrow_region_vid); let region_sub = self.regioncx.find_sub_region_live_at(borrow_region_vid, location); - debug!("explain_why_borrow_contains_point: region_sub={:?}", region_sub); + debug!(?region_sub); match find_use::find(body, regioncx, tcx, region_sub, location) { Some(Cause::LiveVar(local, location)) => { @@ -392,7 +401,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { None => { if let Some(region) = self.to_error_region_vid(borrow_region_vid) { - let (category, from_closure, span, region_name) = + let (category, from_closure, span, region_name, extra_info) = 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()); @@ -402,19 +411,14 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { span, region_name, opt_place_desc, + extra_info, } } else { - debug!( - "explain_why_borrow_contains_point: \ - Could not generate a region name" - ); + debug!("Could not generate a region name"); BorrowExplanation::Unexplained } } else { - debug!( - "explain_why_borrow_contains_point: \ - Could not generate an error region vid" - ); + debug!("Could not generate an error region vid"); BorrowExplanation::Unexplained } } @@ -455,7 +459,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { return outmost_back_edge; } - let block = &self.body.basic_blocks()[location.block]; + let block = &self.body.basic_blocks[location.block]; if location.statement_index < block.statements.len() { let successor = location.successor_within_block(); @@ -514,7 +518,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { } if loop_head.dominates(from, &self.dominators) { - let block = &self.body.basic_blocks()[from.block]; + let block = &self.body.basic_blocks[from.block]; if from.statement_index < block.statements.len() { let successor = from.successor_within_block(); @@ -564,7 +568,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { UseSpans::PatUse(span) | UseSpans::OtherUse(span) | UseSpans::FnSelfUse { var_span: span, .. } => { - let block = &self.body.basic_blocks()[location.block]; + let block = &self.body.basic_blocks[location.block]; let kind = if let Some(&Statement { kind: StatementKind::FakeRead(box (FakeReadCause::ForLet(_), _)), |