Auto merge of #103171 - jackh726:gen-interior-hrtb-error, r=cjgillot

Better error for HRTB error from generator interior

cc #100013

This is just a first pass at an error. It could be better, and shouldn't really be emitted in the first place. But this is better than what was being emitted before.

5 files changed, 15 insertions, 11 deletions

diff --git a/compiler/rustc_middle/src/infer/canonical.rs b/compiler/rustc_middle/src/infer/canonical.rs
index 8d1ed4b2a52..0331d764b38 100644
--- a/compiler/rustc_middle/src/infer/canonical.rs
+++ b/compiler/rustc_middle/src/infer/canonical.rs
@@ -336,8 +336,10 @@ impl<'tcx> CanonicalVarValues<'tcx> {
                         tcx.mk_ty(ty::Bound(ty::INNERMOST, ty::BoundVar::from_u32(i).into())).into()
                     }
                     GenericArgKind::Lifetime(..) => {
-                        let br =
-                            ty::BoundRegion { var: ty::BoundVar::from_u32(i), kind: ty::BrAnon(i) };
+                        let br = ty::BoundRegion {
+                            var: ty::BoundVar::from_u32(i),
+                            kind: ty::BrAnon(i, None),
+                        };
                         tcx.mk_region(ty::ReLateBound(ty::INNERMOST, br)).into()
                     }
                     GenericArgKind::Const(ct) => tcx
diff --git a/compiler/rustc_middle/src/ty/fold.rs b/compiler/rustc_middle/src/ty/fold.rs
index a329753726e..2842b3c3102 100644
--- a/compiler/rustc_middle/src/ty/fold.rs
+++ b/compiler/rustc_middle/src/ty/fold.rs
@@ -598,7 +598,7 @@ impl<'tcx> TyCtxt<'tcx> {
             .replace_late_bound_regions(sig, |_| {
                 let br = ty::BoundRegion {
                     var: ty::BoundVar::from_u32(counter),
-                    kind: ty::BrAnon(counter),
+                    kind: ty::BrAnon(counter, None),
                 };
                 let r = self.mk_region(ty::ReLateBound(ty::INNERMOST, br));
                 counter += 1;
@@ -606,7 +606,7 @@ impl<'tcx> TyCtxt<'tcx> {
             })
             .0;
         let bound_vars = self.mk_bound_variable_kinds(
-            (0..counter).map(|i| ty::BoundVariableKind::Region(ty::BrAnon(i))),
+            (0..counter).map(|i| ty::BoundVariableKind::Region(ty::BrAnon(i, None))),
         );
         Binder::bind_with_vars(inner, bound_vars)
     }
@@ -626,7 +626,9 @@ 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(index as u32)))
+                    .or_insert_with(|| {
+                        ty::BoundVariableKind::Region(ty::BrAnon(index as u32, None))
+                    })
                     .expect_region();
                 let br = ty::BoundRegion { var, kind };
                 self.tcx.mk_region(ty::ReLateBound(ty::INNERMOST, br))
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index fab85c39d25..c8815537835 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -2115,7 +2115,7 @@ impl<'a, 'tcx> ty::TypeFolder<'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 };
@@ -2226,10 +2226,10 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
                     let ty::BoundVariableKind::Region(var) = var else {
                     // This doesn't really matter because it doesn't get used,
                     // it's just an empty value
-                    return ty::BrAnon(0);
+                    return ty::BrAnon(0, None);
                 };
                     match var {
-                        ty::BrAnon(_) | ty::BrEnv => {
+                        ty::BrAnon(..) | ty::BrEnv => {
                             start_or_continue(&mut self, "for<", ", ");
                             let name = next_name(&self);
                             debug!(?name);
@@ -2271,7 +2271,7 @@ 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 {
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index f2070869ce0..9f0598d0ba8 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/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(n) => write!(f, "BrAnon({:?})", n),
+            ty::BrAnon(n, span) => write!(f, "BrAnon({n:?}, {span:?})"),
             ty::BrNamed(did, name) => {
                 if did.is_crate_root() {
                     write!(f, "BrNamed({})", name)
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index 5f108bf0ef3..49d82b503a4 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -59,7 +59,7 @@ pub struct FreeRegion {
 #[derive(HashStable)]
 pub enum BoundRegionKind {
     /// An anonymous region parameter for a given fn (&T)
-    BrAnon(u32),
+    BrAnon(u32, Option<Span>),
 
     /// Named region parameters for functions (a in &'a T)
     ///