From bc64bfd75b133b5e0654d08f112a17e4ea0b98cc Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Fri, 25 Jul 2025 10:44:52 +1000
Subject: [PATCH] Tweak bound region pre-interning.

- Cover `DebruijnIndex(2)`, for slightly better coverage.
- Rename some things, to account for other region things that were
  renamed.
---
 compiler/rustc_middle/src/ty/context.rs | 14 +++++++-------
 compiler/rustc_middle/src/ty/region.rs  |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 7e6bcfee0254..975aa0116c4b 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1044,8 +1044,8 @@ const NUM_PREINTERNED_FRESH_FLOAT_TYS: u32 = 3;
 
 // This number may seem high, but it is reached in all but the smallest crates.
 const NUM_PREINTERNED_RE_VARS: u32 = 500;
-const NUM_PREINTERNED_RE_LATE_BOUNDS_I: u32 = 2;
-const NUM_PREINTERNED_RE_LATE_BOUNDS_V: u32 = 20;
+const NUM_PREINTERNED_ANON_RE_BOUNDS_I: u32 = 3;
+const NUM_PREINTERNED_ANON_RE_BOUNDS_V: u32 = 20;
 
 pub struct CommonTypes<'tcx> {
     pub unit: Ty<'tcx>,
@@ -1101,9 +1101,9 @@ pub struct CommonLifetimes<'tcx> {
     pub re_vars: Vec<Region<'tcx>>,
 
     /// Pre-interned values of the form:
-    /// `ReBound(DebruijnIndex(i), BoundRegion { var: v, kind: BrAnon })`
+    /// `ReBound(DebruijnIndex(i), BoundRegion { var: v, kind: BoundRegionKind::Anon })`
     /// for small values of `i` and `v`.
-    pub re_late_bounds: Vec<Vec<Region<'tcx>>>,
+    pub anon_re_bounds: Vec<Vec<Region<'tcx>>>,
 }
 
 pub struct CommonConsts<'tcx> {
@@ -1176,9 +1176,9 @@ impl<'tcx> CommonLifetimes<'tcx> {
         let re_vars =
             (0..NUM_PREINTERNED_RE_VARS).map(|n| mk(ty::ReVar(ty::RegionVid::from(n)))).collect();
 
-        let re_late_bounds = (0..NUM_PREINTERNED_RE_LATE_BOUNDS_I)
+        let anon_re_bounds = (0..NUM_PREINTERNED_ANON_RE_BOUNDS_I)
             .map(|i| {
-                (0..NUM_PREINTERNED_RE_LATE_BOUNDS_V)
+                (0..NUM_PREINTERNED_ANON_RE_BOUNDS_V)
                     .map(|v| {
                         mk(ty::ReBound(
                             ty::DebruijnIndex::from(i),
@@ -1196,7 +1196,7 @@ impl<'tcx> CommonLifetimes<'tcx> {
             re_static: mk(ty::ReStatic),
             re_erased: mk(ty::ReErased),
             re_vars,
-            re_late_bounds,
+            anon_re_bounds,
         }
     }
 }
diff --git a/compiler/rustc_middle/src/ty/region.rs b/compiler/rustc_middle/src/ty/region.rs
index 51be93d9a72a..5cf960721776 100644
--- a/compiler/rustc_middle/src/ty/region.rs
+++ b/compiler/rustc_middle/src/ty/region.rs
@@ -54,7 +54,7 @@ impl<'tcx> Region<'tcx> {
     ) -> Region<'tcx> {
         // Use a pre-interned one when possible.
         if let ty::BoundRegion { var, kind: ty::BoundRegionKind::Anon } = bound_region
-            && let Some(inner) = tcx.lifetimes.re_late_bounds.get(debruijn.as_usize())
+            && let Some(inner) = tcx.lifetimes.anon_re_bounds.get(debruijn.as_usize())
             && let Some(re) = inner.get(var.as_usize()).copied()
         {
             re