Auto merge of rust-lang#101902 - jackh726:revert-static-hrtb-error, r=nikomatsakis

Partially revert rust-lang#101433

reverts rust-lang#101433 to fix rust-lang#101844

We should get this into the beta cut, since the ICE is getting hit quite a bit.

Author: bors

compiler/rustc_borrowck/src/constraints/mod.rs

@@ -21,7 +21,10 @@ pub(crate) struct OutlivesConstraintSet<'tcx> {
 
 impl<'tcx> OutlivesConstraintSet<'tcx> {
     pub(crate) fn push(&mut self, constraint: OutlivesConstraint<'tcx>) {
-        debug!("OutlivesConstraintSet::push({:?})", constraint);
+        debug!(
+            "OutlivesConstraintSet::push({:?}: {:?} @ {:?}",
+            constraint.sup, constraint.sub, constraint.locations
+        );
         if constraint.sup == constraint.sub {
             // 'a: 'a is pretty uninteresting
             return;

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, ExtraConstraintInfo};
+use crate::region_infer::BlameConstraint;
 use crate::{
     borrow_set::BorrowData, nll::ConstraintDescription, region_infer::Cause, MirBorrowckCtxt,
     WriteKind,
@@ -38,7 +38,6 @@ pub(crate) enum BorrowExplanation<'tcx> {
         span: Span,
         region_name: RegionName,
         opt_place_desc: Option<String>,
-        extra_info: Vec<ExtraConstraintInfo>,
     },
     Unexplained,
 }
@@ -244,7 +243,6 @@ impl<'tcx> BorrowExplanation<'tcx> {
                 ref region_name,
                 ref opt_place_desc,
                 from_closure: _,
-                ref extra_info,
             } => {
                 region_name.highlight_region_name(err);
 
@@ -270,14 +268,6 @@ 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);
             }
             _ => {}
@@ -319,17 +309,16 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &self,
         borrow_region: RegionVid,
         outlived_region: RegionVid,
-    ) -> (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;
+    ) -> (ConstraintCategory<'tcx>, bool, Span, Option<RegionName>) {
+        let BlameConstraint { category, from_closure, cause, variance_info: _ } = self
+            .regioncx
+            .best_blame_constraint(borrow_region, NllRegionVariableOrigin::FreeRegion, |r| {
+                self.regioncx.provides_universal_region(r, borrow_region, 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)
     }
 
     /// Returns structured explanation for *why* the borrow contains the
@@ -401,7 +390,7 @@ 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, extra_info) =
+                    let (category, from_closure, span, region_name) =
                         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());
@@ -411,7 +400,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             span,
                             region_name,
                             opt_place_desc,
-                            extra_info,
                         }
                     } else {
                         debug!("Could not generate a region name");

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -31,7 +31,7 @@ use crate::session_diagnostics::{
 };
 
 use super::{OutlivesSuggestionBuilder, RegionName};
-use crate::region_infer::{BlameConstraint, ExtraConstraintInfo};
+use crate::region_infer::BlameConstraint;
 use crate::{
     nll::ConstraintDescription,
     region_infer::{values::RegionElement, TypeTest},
@@ -354,11 +354,10 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     ) {
         debug!("report_region_error(fr={:?}, outlived_fr={:?})", fr, outlived_fr);
 
-        let (blame_constraint, extra_info) =
+        let BlameConstraint { category, cause, variance_info, from_closure: _ } =
             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);
 
@@ -467,14 +466,6 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             }
         }
 
-        for extra in extra_info {
-            match extra {
-                ExtraConstraintInfo::PlaceholderFromPredicate(span) => {
-                    diag.span_note(span, format!("due to current limitations in the borrow checker, this implies a `'static` lifetime"));
-                }
-            }
-        }
-
         self.buffer_error(diag);
     }
 
@@ -566,7 +557,6 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     /// LL |     ref_obj(x)
     ///    |     ^^^^^^^^^^ `x` escapes the function body here
     /// ```
-    #[instrument(level = "debug", skip(self))]
     fn report_escaping_data_error(
         &self,
         errci: &ErrorConstraintInfo<'tcx>,

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -245,11 +245,6 @@ enum Trace<'tcx> {
     NotVisited,
 }
 
-#[derive(Clone, PartialEq, Eq, Debug)]
-pub enum ExtraConstraintInfo {
-    PlaceholderFromPredicate(Span),
-}
-
 impl<'tcx> RegionInferenceContext<'tcx> {
     /// Creates a new region inference context with a total of
     /// `num_region_variables` valid inference variables; the first N
@@ -1823,9 +1818,10 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         fr1_origin: NllRegionVariableOrigin,
         fr2: RegionVid,
     ) -> (ConstraintCategory<'tcx>, ObligationCause<'tcx>) {
-        let BlameConstraint { category, cause, .. } = self
-            .best_blame_constraint(fr1, fr1_origin, |r| self.provides_universal_region(r, fr1, fr2))
-            .0;
+        let BlameConstraint { category, cause, .. } =
+            self.best_blame_constraint(fr1, fr1_origin, |r| {
+                self.provides_universal_region(r, fr1, fr2)
+            });
         (category, cause)
     }
 
@@ -2014,7 +2010,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         from_region: RegionVid,
         from_region_origin: NllRegionVariableOrigin,
         target_test: impl Fn(RegionVid) -> bool,
-    ) -> (BlameConstraint<'tcx>, Vec<ExtraConstraintInfo>) {
+    ) -> BlameConstraint<'tcx> {
         // Find all paths
         let (path, target_region) =
             self.find_constraint_paths_between_regions(from_region, target_test).unwrap();
@@ -2030,18 +2026,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 .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.
         // Instead, we use it to produce an improved `ObligationCauseCode`.
         // FIXME - determine what we should do if we encounter multiple `ConstraintCategory::Predicate`
@@ -2089,7 +2073,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                     from_closure,
                     cause: ObligationCause::new(span, CRATE_HIR_ID, cause_code),
                     variance_info: constraint.variance_info,
-                    outlives_constraint: *constraint,
                 }
             })
             .collect();
@@ -2191,7 +2174,7 @@ 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) {
@@ -2200,7 +2183,7 @@ 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();
                 }
             }
 
@@ -2220,7 +2203,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 }
             }
 
-            return (categorized_path[i].clone(), extra_info);
+            return categorized_path[i].clone();
         }
 
         // If that search fails, that is.. unusual. Maybe everything
@@ -2230,7 +2213,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         categorized_path.sort_by(|p0, p1| p0.category.cmp(&p1.category));
         debug!("sorted_path={:#?}", categorized_path);
 
-        (categorized_path.remove(0), extra_info)
+        categorized_path.remove(0)
     }
 
     pub(crate) fn universe_info(&self, universe: ty::UniverseIndex) -> UniverseInfo<'tcx> {
@@ -2312,13 +2295,7 @@ impl<'tcx> ClosureRegionRequirementsExt<'tcx> for ClosureRegionRequirements<'tcx
                              outlives_requirement={:?}",
                             region, outlived_region, outlives_requirement,
                         );
-                        (
-                            ty::Binder::dummy(ty::OutlivesPredicate(
-                                region.into(),
-                                outlived_region,
-                            )),
-                            ConstraintCategory::BoringNoLocation,
-                        )
+                        ty::Binder::dummy(ty::OutlivesPredicate(region.into(), outlived_region))
                     }
 
                     ClosureOutlivesSubject::Ty(ty) => {
@@ -2328,10 +2305,7 @@ impl<'tcx> ClosureRegionRequirementsExt<'tcx> for ClosureRegionRequirements<'tcx
                              outlives_requirement={:?}",
                             ty, outlived_region, outlives_requirement,
                         );
-                        (
-                            ty::Binder::dummy(ty::OutlivesPredicate(ty.into(), outlived_region)),
-                            ConstraintCategory::BoringNoLocation,
-                        )
+                        ty::Binder::dummy(ty::OutlivesPredicate(ty.into(), outlived_region))
                     }
                 }
             })
@@ -2345,5 +2319,4 @@ pub struct BlameConstraint<'tcx> {
     pub from_closure: bool,
     pub cause: ObligationCause<'tcx>,
     pub variance_info: ty::VarianceDiagInfo<'tcx>,
-    pub outlives_constraint: OutlivesConstraint<'tcx>,
 }

compiler/rustc_borrowck/src/type_check/canonical.rs

@@ -25,7 +25,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     /// constraints should occur within this method so that those
     /// constraints can be properly localized!**
     #[instrument(skip(self, op), level = "trace")]
-    pub(super) fn fully_perform_op<R: fmt::Debug, Op>(
+    pub(super) fn fully_perform_op<R, Op>(
         &mut self,
         locations: Locations,
         category: ConstraintCategory<'tcx>,
@@ -39,8 +39,6 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
         let TypeOpOutput { output, constraints, error_info } = op.fully_perform(self.infcx)?;
 
-        debug!(?output, ?constraints);
-
         if let Some(data) = constraints {
             self.push_region_constraints(locations, category, data);
         }
@@ -104,7 +102,6 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         );
     }
 
-    #[instrument(level = "debug", skip(self))]
     pub(super) fn normalize_and_prove_instantiated_predicates(
         &mut self,
         // Keep this parameter for now, in case we start using
@@ -119,9 +116,8 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             .zip(instantiated_predicates.spans.into_iter())
         {
             debug!(?predicate);
-            let category = ConstraintCategory::Predicate(span);
-            let predicate = self.normalize_with_category(predicate, locations, category);
-            self.prove_predicate(predicate, locations, category);
+            let predicate = self.normalize(predicate, locations);
+            self.prove_predicate(predicate, locations, ConstraintCategory::Predicate(span));
         }
     }
 
@@ -157,27 +153,15 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         })
     }
 
-    pub(super) fn normalize<T>(&mut self, value: T, location: impl NormalizeLocation) -> T
-    where
-        T: type_op::normalize::Normalizable<'tcx> + fmt::Display + Copy + 'tcx,
-    {
-        self.normalize_with_category(value, location, ConstraintCategory::Boring)
-    }
-
     #[instrument(skip(self), level = "debug")]
-    pub(super) fn normalize_with_category<T>(
-        &mut self,
-        value: T,
-        location: impl NormalizeLocation,
-        category: ConstraintCategory<'tcx>,
-    ) -> T
+    pub(super) fn normalize<T>(&mut self, value: T, location: impl NormalizeLocation) -> T
     where
         T: type_op::normalize::Normalizable<'tcx> + fmt::Display + Copy + 'tcx,
     {
         let param_env = self.param_env;
         self.fully_perform_op(
             location.to_locations(),
-            category,
+            ConstraintCategory::Boring,
             param_env.and(type_op::normalize::Normalize::new(value)),
         )
         .unwrap_or_else(|NoSolution| {