Remove span from BrAnon.

compiler/rustc_borrowck/src/diagnostics/region_name.rs

@@ -354,7 +354,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
                     })
                 }
 
-                ty::BoundRegionKind::BrAnon(..) => None,
+                ty::BoundRegionKind::BrAnon => None,
             },
 
             ty::ReLateBound(..)

compiler/rustc_borrowck/src/renumber.rs

@@ -7,7 +7,7 @@ use rustc_middle::mir::visit::{MutVisitor, TyContext};
 use rustc_middle::mir::{Body, ConstOperand, Location, Promoted};
 use rustc_middle::ty::GenericArgsRef;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
-use rustc_span::{Span, Symbol};
+use rustc_span::Symbol;
 
 /// Replaces all free regions appearing in the MIR with fresh
 /// inference variables, returning the number of variables created.
@@ -28,21 +28,15 @@ pub fn renumber_mir<'tcx>(
     renumberer.visit_body(body);
 }
 
-#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
-pub(crate) enum BoundRegionInfo {
-    Name(Symbol),
-    Span(Span),
-}
-
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
 pub(crate) enum RegionCtxt {
     Location(Location),
     TyContext(TyContext),
     Free(Symbol),
-    Bound(BoundRegionInfo),
+    Bound(Symbol),
-    LateBound(BoundRegionInfo),
+    LateBound(Symbol),
     Existential(Option<Symbol>),
-    Placeholder(BoundRegionInfo),
+    Placeholder(Symbol),
     Unknown,
 }
 

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1367,14 +1367,13 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                     }
                 };
                 let (sig, map) = tcx.replace_late_bound_regions(sig, |br| {
-                    use crate::renumber::{BoundRegionInfo, RegionCtxt};
+                    use crate::renumber::RegionCtxt;
 
                     let region_ctxt_fn = || {
                         let reg_info = match br.kind {
-                            ty::BoundRegionKind::BrAnon(Some(span)) => BoundRegionInfo::Span(span),
+                            ty::BoundRegionKind::BrAnon => sym::anon,
-                            ty::BoundRegionKind::BrAnon(..) => BoundRegionInfo::Name(sym::anon),
+                            ty::BoundRegionKind::BrNamed(_, name) => name,
-                            ty::BoundRegionKind::BrNamed(_, name) => BoundRegionInfo::Name(name),
+                            ty::BoundRegionKind::BrEnv => sym::env,
-                            ty::BoundRegionKind::BrEnv => BoundRegionInfo::Name(sym::env),
                         };
 
                         RegionCtxt::LateBound(reg_info)

compiler/rustc_borrowck/src/type_check/relate_tys.rs

@@ -11,7 +11,7 @@ use rustc_span::{Span, Symbol};
 
 use crate::constraints::OutlivesConstraint;
 use crate::diagnostics::UniverseInfo;
-use crate::renumber::{BoundRegionInfo, RegionCtxt};
+use crate::renumber::RegionCtxt;
 use crate::type_check::{InstantiateOpaqueType, Locations, TypeChecker};
 
 impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
@@ -126,10 +126,9 @@ impl<'tcx> TypeRelatingDelegate<'tcx> for NllTypeRelatingDelegate<'_, '_, 'tcx>
             .placeholder_region(self.type_checker.infcx, placeholder);
 
         let reg_info = match placeholder.bound.kind {
-            ty::BoundRegionKind::BrAnon(Some(span)) => BoundRegionInfo::Span(span),
+            ty::BoundRegionKind::BrAnon => sym::anon,
-            ty::BoundRegionKind::BrAnon(..) => BoundRegionInfo::Name(sym::anon),
+            ty::BoundRegionKind::BrNamed(_, name) => name,
-            ty::BoundRegionKind::BrNamed(_, name) => BoundRegionInfo::Name(name),
+            ty::BoundRegionKind::BrEnv => sym::env,
-            ty::BoundRegionKind::BrEnv => BoundRegionInfo::Name(sym::env),
         };
 
         if cfg!(debug_assertions) {

compiler/rustc_borrowck/src/universal_regions.rs

@@ -28,7 +28,7 @@ use rustc_span::symbol::{kw, sym};
 use rustc_span::Symbol;
 use std::iter;
 
-use crate::renumber::{BoundRegionInfo, RegionCtxt};
+use crate::renumber::RegionCtxt;
 use crate::BorrowckInferCtxt;
 
 #[derive(Debug)]
@@ -446,9 +446,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
                     if !indices.indices.contains_key(&r) {
                         let region_vid = {
                             let name = r.get_name_or_anon();
-                            self.infcx.next_nll_region_var(FR, || {
+                            self.infcx.next_nll_region_var(FR, || RegionCtxt::LateBound(name))
-                                RegionCtxt::LateBound(BoundRegionInfo::Name(name))
-                            })
                         };
 
                         debug!(?region_vid);
@@ -480,9 +478,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
             if !indices.indices.contains_key(&r) {
                 let region_vid = {
                     let name = r.get_name_or_anon();
-                    self.infcx.next_nll_region_var(FR, || {
+                    self.infcx.next_nll_region_var(FR, || RegionCtxt::LateBound(name))
-                        RegionCtxt::LateBound(BoundRegionInfo::Name(name))
-                    })
                 };
 
                 debug!(?region_vid);
@@ -796,7 +792,7 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for BorrowckInferCtxt<'cx, 'tcx> {
                     _ => sym::anon,
                 };
 
-                self.next_nll_region_var(origin, || RegionCtxt::Bound(BoundRegionInfo::Name(name)))
+                self.next_nll_region_var(origin, || RegionCtxt::Bound(name))
             };
 
             indices.insert_late_bound_region(liberated_region, region_vid.as_var());
@@ -826,9 +822,7 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for BorrowckInferCtxt<'cx, 'tcx> {
             if !indices.indices.contains_key(&r) {
                 let region_vid = {
                     let name = r.get_name_or_anon();
-                    self.next_nll_region_var(FR, || {
+                    self.next_nll_region_var(FR, || RegionCtxt::LateBound(name))
-                        RegionCtxt::LateBound(BoundRegionInfo::Name(name))
-                    })
                 };
 
                 debug!(?region_vid);
@@ -848,9 +842,7 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for BorrowckInferCtxt<'cx, 'tcx> {
             if !indices.indices.contains_key(&r) {
                 let region_vid = {
                     let name = r.get_name_or_anon();
-                    self.next_nll_region_var(FR, || {
+                    self.next_nll_region_var(FR, || RegionCtxt::LateBound(name))
-                        RegionCtxt::LateBound(BoundRegionInfo::Name(name))
-                    })
                 };
 
                 indices.insert_late_bound_region(r, region_vid.as_var());

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -2781,7 +2781,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     ) {
         for br in referenced_regions.difference(&constrained_regions) {
             let br_name = match *br {
-                ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon(..) | ty::BrEnv => {
+                ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon | ty::BrEnv => {
                     "an anonymous lifetime".to_string()
                 }
                 ty::BrNamed(_, name) => format!("lifetime `{name}`"),
@@ -2789,7 +2789,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
             let mut err = generate_err(&br_name);
 
-            if let ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon(..) = *br {
+            if let ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon = *br {
                 // The only way for an anonymous lifetime to wind up
                 // in the return type but **also** be unconstrained is
                 // if it only appears in "associated types" in the

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -137,7 +137,7 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
     let name_str = intrinsic_name.as_str();
 
     let bound_vars = tcx.mk_bound_variable_kinds(&[
-        ty::BoundVariableKind::Region(ty::BrAnon(None)),
+        ty::BoundVariableKind::Region(ty::BrAnon),
         ty::BoundVariableKind::Region(ty::BrEnv),
     ]);
     let mk_va_list_ty = |mutbl| {
@@ -145,7 +145,7 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
             let region = ty::Region::new_late_bound(
                 tcx,
                 ty::INNERMOST,
-                ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon(None) },
+                ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon },
             );
             let env_region = ty::Region::new_late_bound(
                 tcx,
@@ -405,7 +405,7 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
                 );
                 let discriminant_def_id = assoc_items[0];
 
-                let br = ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon(None) };
+                let br = ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon };
                 (
                     1,
                     vec![Ty::new_imm_ref(
@@ -463,7 +463,7 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
             }
 
             sym::raw_eq => {
-                let br = ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon(None) };
+                let br = ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon };
                 let param_ty = Ty::new_imm_ref(
                     tcx,
                     ty::Region::new_late_bound(tcx, ty::INNERMOST, br),

compiler/rustc_hir_typeck/src/check.rs

@@ -204,7 +204,7 @@ fn check_panic_info_fn(tcx: TyCtxt<'_>, fn_id: LocalDefId, fn_sig: ty::FnSig<'_>
         &[ty::GenericArg::from(ty::Region::new_late_bound(
             tcx,
             ty::INNERMOST,
-            ty::BoundRegion { var: ty::BoundVar::from_u32(1), kind: ty::BrAnon(None) },
+            ty::BoundRegion { var: ty::BoundVar::from_u32(1), kind: ty::BrAnon },
         ))],
     );
     let panic_info_ref_ty = Ty::new_imm_ref(
@@ -212,14 +212,14 @@ fn check_panic_info_fn(tcx: TyCtxt<'_>, fn_id: LocalDefId, fn_sig: ty::FnSig<'_>
         ty::Region::new_late_bound(
             tcx,
             ty::INNERMOST,
-            ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon(None) },
+            ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon },
         ),
         panic_info_ty,
     );
 
     let bounds = tcx.mk_bound_variable_kinds(&[
-        ty::BoundVariableKind::Region(ty::BrAnon(None)),
+        ty::BoundVariableKind::Region(ty::BrAnon),
-        ty::BoundVariableKind::Region(ty::BrAnon(None)),
+        ty::BoundVariableKind::Region(ty::BrAnon),
     ]);
     let expected_sig = ty::Binder::bind_with_vars(
         tcx.mk_fn_sig([panic_info_ref_ty], tcx.types.never, false, fn_sig.unsafety, Abi::Rust),

compiler/rustc_infer/src/errors/note_and_explain.rs

@@ -56,11 +56,8 @@ impl<'a> DescriptionCtx<'a> {
                                 (Some(span), "as_defined", name.to_string())
                             }
                         }
-                        ty::BrAnon(span) => {
+                        ty::BrAnon => {
-                            let span = match span {
+                            let span = Some(tcx.def_span(scope));
-                                Some(_) => span,
-                                None => Some(tcx.def_span(scope)),
-                            };
                             (span, "defined_here", String::new())
                         }
                         _ => {

compiler/rustc_infer/src/infer/canonical/canonicalizer.rs

@@ -775,7 +775,7 @@ impl<'cx, 'tcx> Canonicalizer<'cx, 'tcx> {
         r: ty::Region<'tcx>,
     ) -> ty::Region<'tcx> {
         let var = self.canonical_var(info, r.into());
-        let br = ty::BoundRegion { var, kind: ty::BrAnon(None) };
+        let br = ty::BoundRegion { var, kind: ty::BrAnon };
         ty::Region::new_late_bound(self.interner(), self.binder_index, br)
     }
 

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -242,12 +242,9 @@ fn msg_span_from_named_region<'tcx>(
                         };
                         (text, Some(span))
                     }
-                    ty::BrAnon(span) => (
+                    ty::BrAnon => (
                         "the anonymous lifetime as defined here".to_string(),
-                        Some(match span {
+                        Some(tcx.def_span(scope))
-                            Some(span) => span,
-                            None => tcx.def_span(scope)
-                        })
                     ),
                     _ => (
                         format!("the lifetime `{region}` as defined here"),
@@ -262,11 +259,7 @@ fn msg_span_from_named_region<'tcx>(
             ..
         }) => (format!("the lifetime `{name}` as defined here"), Some(tcx.def_span(def_id))),
         ty::RePlaceholder(ty::PlaceholderRegion {
-            bound: ty::BoundRegion { kind: ty::BoundRegionKind::BrAnon(Some(span)), .. },
+            bound: ty::BoundRegion { kind: ty::BoundRegionKind::BrAnon, .. },
-            ..
-        }) => ("the anonymous lifetime defined here".to_owned(), Some(span)),
-        ty::RePlaceholder(ty::PlaceholderRegion {
-            bound: ty::BoundRegion { kind: ty::BoundRegionKind::BrAnon(None), .. },
             ..
         }) => ("an anonymous lifetime".to_owned(), None),
         _ => bug!("{:?}", region),

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs

@@ -61,7 +61,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         let is_impl_item = region_info.is_impl_item;
 
         match br {
-            ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon(..) => {}
+            ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon => {}
             _ => {
                 /* not an anonymous region */
                 debug!("try_report_named_anon_conflict: not an anonymous region");

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_relation.rs

@@ -36,15 +36,13 @@ impl<'tcx> NiceRegionError<'_, 'tcx> {
                     ty::BrNamed(def_id, symbol) => {
                         (Some(self.tcx().def_span(def_id)), Some(symbol))
                     }
-                    ty::BrAnon(span) => (*span, None),
+                    ty::BrAnon | ty::BrEnv => (None, None),
-                    ty::BrEnv => (None, None),
                 };
                 let (sup_span, sup_symbol) = match sup_name {
                     ty::BrNamed(def_id, symbol) => {
                         (Some(self.tcx().def_span(def_id)), Some(symbol))
                     }
-                    ty::BrAnon(span) => (*span, None),
+                    ty::BrAnon | ty::BrEnv => (None, None),
-                    ty::BrEnv => (None, None),
                 };
                 let diag = match (sub_span, sup_span, sub_symbol, sup_symbol) {
                     (Some(sub_span), Some(sup_span), Some(&sub_symbol), Some(&sup_symbol)) => {

compiler/rustc_middle/src/infer/canonical.rs

@@ -455,7 +455,7 @@ impl<'tcx> CanonicalVarValues<'tcx> {
                         CanonicalVarKind::Region(_) | CanonicalVarKind::PlaceholderRegion(_) => {
                             let br = ty::BoundRegion {
                                 var: ty::BoundVar::from_usize(i),
-                                kind: ty::BrAnon(None),
+                                kind: ty::BrAnon,
                             };
                             ty::Region::new_late_bound(tcx, ty::INNERMOST, br).into()
                         }

compiler/rustc_middle/src/mir/query.rs

@@ -414,8 +414,7 @@ impl<'tcx> ClosureOutlivesSubjectTy<'tcx> {
     pub fn bind(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Self {
         let inner = tcx.fold_regions(ty, |r, depth| match r.kind() {
             ty::ReVar(vid) => {
-                let br =
+                let br = ty::BoundRegion { var: ty::BoundVar::new(vid.index()), kind: ty::BrAnon };
-                    ty::BoundRegion { var: ty::BoundVar::new(vid.index()), kind: ty::BrAnon(None) };
                 ty::Region::new_late_bound(tcx, depth, br)
             }
             _ => bug!("unexpected region in ClosureOutlivesSubjectTy: {r:?}"),

compiler/rustc_middle/src/ty/context.rs

@@ -318,7 +318,7 @@ pub struct CommonLifetimes<'tcx> {
     pub re_vars: Vec<Region<'tcx>>,
 
     /// Pre-interned values of the form:
-    /// `ReLateBound(DebruijnIndex(i), BoundRegion { var: v, kind: BrAnon(None) })`
+    /// `ReLateBound(DebruijnIndex(i), BoundRegion { var: v, kind: BrAnon })`
     /// for small values of `i` and `v`.
     pub re_late_bounds: Vec<Vec<Region<'tcx>>>,
 }
@@ -395,7 +395,7 @@ impl<'tcx> CommonLifetimes<'tcx> {
                     .map(|v| {
                         mk(ty::ReLateBound(
                             ty::DebruijnIndex::from(i),
-                            ty::BoundRegion { var: ty::BoundVar::from(v), kind: ty::BrAnon(None) },
+                            ty::BoundRegion { var: ty::BoundVar::from(v), kind: ty::BrAnon },
                         ))
                     })
                     .collect()

compiler/rustc_middle/src/ty/fold.rs

@@ -385,7 +385,7 @@ impl<'tcx> TyCtxt<'tcx> {
                 let index = entry.index();
                 let var = ty::BoundVar::from_usize(index);
                 let kind = entry
-                    .or_insert_with(|| ty::BoundVariableKind::Region(ty::BrAnon(None)))
+                    .or_insert_with(|| ty::BoundVariableKind::Region(ty::BrAnon))
                     .expect_region();
                 let br = ty::BoundRegion { var, kind };
                 ty::Region::new_late_bound(self.tcx, ty::INNERMOST, br)

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -2330,7 +2330,7 @@ impl<'a, 'tcx> ty::TypeFolder<TyCtxt<'tcx>> for RegionFolder<'a, 'tcx> {
                 // If this is an anonymous placeholder, don't rename. Otherwise, in some
                 // async fns, we get a `for<'r> Send` bound
                 match kind {
-                    ty::BrAnon(..) | ty::BrEnv => r,
+                    ty::BrAnon | ty::BrEnv => r,
                     _ => {
                         // Index doesn't matter, since this is just for naming and these never get bound
                         let br = ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind };
@@ -2451,7 +2451,7 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
                             binder_level_idx: ty::DebruijnIndex,
                             br: ty::BoundRegion| {
                 let (name, kind) = match br.kind {
-                    ty::BrAnon(..) | ty::BrEnv => {
+                    ty::BrAnon | ty::BrEnv => {
                         let name = next_name(&self);
 
                         if let Some(lt_idx) = lifetime_idx {

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -68,7 +68,7 @@ impl<'tcx> fmt::Debug for ty::adjustment::Adjustment<'tcx> {
 impl fmt::Debug for ty::BoundRegionKind {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
-            ty::BrAnon(span) => write!(f, "BrAnon({span:?})"),
+            ty::BrAnon => write!(f, "BrAnon"),
             ty::BrNamed(did, name) => {
                 if did.is_crate_root() {
                     write!(f, "BrNamed({name})")

compiler/rustc_middle/src/ty/sty.rs

@@ -69,7 +69,7 @@ pub struct FreeRegion {
 #[derive(HashStable)]
 pub enum BoundRegionKind {
     /// An anonymous region parameter for a given fn (&T)
-    BrAnon(Option<Span>),
+    BrAnon,
 
     /// Named region parameters for functions (a in &'a T)
     ///
@@ -1465,7 +1465,7 @@ impl<'tcx> Region<'tcx> {
         bound_region: ty::BoundRegion,
     ) -> Region<'tcx> {
         // Use a pre-interned one when possible.
-        if let ty::BoundRegion { var, kind: ty::BrAnon(None) } = bound_region
+        if let ty::BoundRegion { var, kind: ty::BrAnon } = bound_region
             && let Some(inner) = tcx.lifetimes.re_late_bounds.get(debruijn.as_usize())
             && let Some(re) = inner.get(var.as_usize()).copied()
         {
@@ -3010,7 +3010,7 @@ mod size_asserts {
     use super::*;
     use rustc_data_structures::static_assert_size;
     // tidy-alphabetical-start
-    static_assert_size!(RegionKind<'_>, 28);
+    static_assert_size!(RegionKind<'_>, 24);
     static_assert_size!(TyKind<'_>, 32);
     // tidy-alphabetical-end
 }

compiler/rustc_smir/src/rustc_smir/mod.rs

@@ -979,13 +979,11 @@ impl<'tcx> Stable<'tcx> for ty::BoundTyKind {
 impl<'tcx> Stable<'tcx> for ty::BoundRegionKind {
     type T = stable_mir::ty::BoundRegionKind;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
         use stable_mir::ty::BoundRegionKind;
 
         match self {
-            ty::BoundRegionKind::BrAnon(option_span) => {
+            ty::BoundRegionKind::BrAnon => BoundRegionKind::BrAnon,
-                BoundRegionKind::BrAnon(option_span.map(|span| span.stable(tables)))
-            }
             ty::BoundRegionKind::BrNamed(def_id, symbol) => {
                 BoundRegionKind::BrNamed(rustc_internal::br_named_def(*def_id), symbol.to_string())
             }

compiler/rustc_smir/src/stable_mir/ty.rs

@@ -286,7 +286,7 @@ pub enum BoundTyKind {
 
 #[derive(Clone, Debug)]
 pub enum BoundRegionKind {
-    BrAnon(Option<Span>),
+    BrAnon,
     BrNamed(BrNamedDef, String),
     BrEnv,
 }

compiler/rustc_symbol_mangling/src/v0.rs

@@ -329,7 +329,7 @@ impl<'tcx> Printer<'tcx> for &mut SymbolMangler<'tcx> {
 
             // Late-bound lifetimes use indices starting at 1,
             // see `BinderLevel` for more details.
-            ty::ReLateBound(debruijn, ty::BoundRegion { var, kind: ty::BrAnon(_) }) => {
+            ty::ReLateBound(debruijn, ty::BoundRegion { var, kind: ty::BrAnon }) => {
                 let binder = &self.binders[self.binders.len() - 1 - debruijn.index()];
                 let depth = binder.lifetime_depths.start + var.as_u32();
 

compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs

@@ -94,8 +94,7 @@ pub(in crate::solve) fn replace_erased_lifetimes_with_bound_vars<'tcx>(
     let mut counter = 0;
     let ty = tcx.fold_regions(ty, |r, current_depth| match r.kind() {
         ty::ReErased => {
-            let br =
+            let br = ty::BoundRegion { var: ty::BoundVar::from_u32(counter), kind: ty::BrAnon };
-                ty::BoundRegion { var: ty::BoundVar::from_u32(counter), kind: ty::BrAnon(None) };
             counter += 1;
             ty::Region::new_late_bound(tcx, current_depth, br)
         }
@@ -103,7 +102,7 @@ pub(in crate::solve) fn replace_erased_lifetimes_with_bound_vars<'tcx>(
         r => bug!("unexpected region: {r:?}"),
     });
     let bound_vars = tcx.mk_bound_variable_kinds_from_iter(
-        (0..counter).map(|_| ty::BoundVariableKind::Region(ty::BrAnon(None))),
+        (0..counter).map(|_| ty::BoundVariableKind::Region(ty::BrAnon)),
     );
     ty::Binder::bind_with_vars(ty, bound_vars)
 }

compiler/rustc_trait_selection/src/solve/canonicalize.rs

@@ -269,7 +269,7 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for Canonicalizer<'_, 'tcx> {
             self.primitive_var_infos.push(CanonicalVarInfo { kind });
             var
         });
-        let br = ty::BoundRegion { var, kind: BrAnon(None) };
+        let br = ty::BoundRegion { var, kind: BrAnon };
         ty::Region::new_late_bound(self.interner(), self.binder_index, br)
     }
 

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -3102,7 +3102,7 @@ fn bind_generator_hidden_types_above<'tcx>(
                         ty::ReErased => {
                             let br = ty::BoundRegion {
                                 var: ty::BoundVar::from_u32(counter),
-                                kind: ty::BrAnon(None),
+                                kind: ty::BrAnon,
                             };
                             counter += 1;
                             ty::Region::new_late_bound(tcx, current_depth, br)
@@ -3118,8 +3118,9 @@ fn bind_generator_hidden_types_above<'tcx>(
     if considering_regions {
         debug_assert!(!hidden_types.has_erased_regions());
     }
-    let bound_vars = tcx.mk_bound_variable_kinds_from_iter(bound_vars.iter().chain(
+    let bound_vars =
-        (num_bound_variables..counter).map(|_| ty::BoundVariableKind::Region(ty::BrAnon(None))),
+        tcx.mk_bound_variable_kinds_from_iter(bound_vars.iter().chain(
-    ));
+            (num_bound_variables..counter).map(|_| ty::BoundVariableKind::Region(ty::BrAnon)),
+        ));
     ty::Binder::bind_with_vars(hidden_types, bound_vars)
 }

tests/ui/nll/closure-requirements/escape-argument-callee.stderr

@@ -6,7 +6,7 @@ LL |         let mut closure = expect_sig(|p, y| *p = y);
    |
    = note: defining type: test::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) mut &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) i32)),
+               for<Region(BrAnon), Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) mut &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon }) i32)),
                (),
            ]
 

tests/ui/nll/closure-requirements/escape-argument.stderr

@@ -6,7 +6,7 @@ LL |         let mut closure = expect_sig(|p, y| *p = y);
    |
    = note: defining type: test::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) mut &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) i32)),
+               for<Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) mut &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) i32)),
                (),
            ]
 

tests/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr

@@ -6,7 +6,7 @@ LL |         |_outlives1, _outlives2, _outlives3, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&'?2 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?3 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) u32>, std::cell::Cell<&'?2 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) &'?3 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>)),
                (),
            ]
    = note: late-bound region is '?4

tests/ui/nll/closure-requirements/propagate-approximated-ref.stderr

@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
    |
    = note: defining type: supply::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) &'?2 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon }) &'?2 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon }) u32>)),
                (),
            ]
    = note: late-bound region is '?3

tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr

@@ -6,7 +6,7 @@ LL |     foo(cell, |cell_a, cell_x| {
    |
    = note: defining type: case1::{closure#0} with closure args [
                i32,
-               for<Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon)> extern "rust-call" fn((std::cell::Cell<&'?1 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) u32>)),
                (),
            ]
 
@@ -36,7 +36,7 @@ LL |     foo(cell, |cell_a, cell_x| {
    |
    = note: defining type: case2::{closure#0} with closure args [
                i32,
-               for<Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon)> extern "rust-call" fn((std::cell::Cell<&'?1 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) u32>)),
                (),
            ]
    = note: number of external vids: 2

tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr

@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon }) u32>)),
                (),
            ]
    = note: late-bound region is '?2

tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr

@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
    |
    = note: defining type: supply::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&'?2 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon }) std::cell::Cell<&'?2 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon }) u32>)),
                (),
            ]
    = note: late-bound region is '?3

tests/ui/nll/closure-requirements/propagate-approximated-val.stderr

@@ -6,7 +6,7 @@ LL |     establish_relationships(cell_a, cell_b, |outlives1, outlives2, x, y| {
    |
    = note: defining type: test::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?2 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) &'?2 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>)),
                (),
            ]
    = note: late-bound region is '?3

tests/ui/nll/closure-requirements/propagate-despite-same-free-region.stderr

@@ -6,7 +6,7 @@ LL |         |_outlives1, _outlives2, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?2 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) &'?2 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>)),
                (),
            ]
    = note: late-bound region is '?3

tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr

@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?1 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) &'?1 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>)),
                (),
            ]
    = note: late-bound region is '?2

tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr

@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
    |
    = note: defining type: supply::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?1 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) &'?2 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) &'?1 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon }) &'?2 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon }) u32>)),
                (),
            ]
    = note: late-bound region is '?3

tests/ui/nll/closure-requirements/return-wrong-bound-region.stderr

@@ -6,7 +6,7 @@ LL |     expect_sig(|a, b| b); // ought to return `a`
    |
    = note: defining type: test::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) i32)) -> &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) i32,
+               for<Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) i32)) -> &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) i32,
                (),
            ]
 

tests/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr

@@ -6,7 +6,7 @@ LL |     twice(cell, value, |a, b| invoke(a, b));
    |
    = note: defining type: generic::<T>::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) T)),
+               for<Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) T)),
                (),
            ]
    = note: number of external vids: 2
@@ -28,7 +28,7 @@ LL |     twice(cell, value, |a, b| invoke(a, b));
    |
    = note: defining type: generic_fail::<T>::{closure#0} with closure args [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) T)),
+               for<Region(BrAnon), Region(BrAnon)> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon }) T)),
                (),
            ]
    = note: late-bound region is '?2