Auto merge of #137040 - jhpratt:rollup-lr17zya, r=jhpratt

Rollup of 11 pull requests

Successful merges:

 - #133312 (triagebot: automatically add more rustdoc related labels)
 - #134016 (Stabilize `const_is_char_boundary` and `const_str_split_at`.)
 - #135813 (CI: split i686-mingw job to three free runners)
 - #136879 (Add safe new() to NotAllOnes)
 - #136971 (Add a new check-pass UI test for returning `impl Fn(T) -> impl Trait`)
 - #136983 (Prepare standard library for Rust 2024 migration)
 - #137002 (Fix early lint check desc in query)
 - #137006 (borrowck diagnostics cleanup: remove an unused and a barely-used field)
 - #137026 (Stabilize (and const-stabilize) `integer_sign_cast`)
 - #137028 (mir_build: Clarify some code for lowering `hir::PatExpr` to THIR)
 - #137032 (Decode metadata buffer in one go)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -147,9 +147,7 @@ pub(crate) enum RegionErrorKind<'tcx> {
 pub(crate) struct ErrorConstraintInfo<'tcx> {
     // fr: outlived_fr
     pub(super) fr: RegionVid,
-    pub(super) fr_is_local: bool,
     pub(super) outlived_fr: RegionVid,
-    pub(super) outlived_fr_is_local: bool,
 
     // Category and span for best blame constraint
     pub(super) category: ConstraintCategory<'tcx>,
@@ -471,14 +469,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             fr_is_local, outlived_fr_is_local, category
         );
 
-        let errci = ErrorConstraintInfo {
-            fr,
-            outlived_fr,
-            fr_is_local,
-            outlived_fr_is_local,
-            category,
-            span: cause.span,
-        };
+        let errci = ErrorConstraintInfo { fr, outlived_fr, category, span: cause.span };
 
         let mut diag = match (category, fr_is_local, outlived_fr_is_local) {
             (ConstraintCategory::Return(kind), true, false) if self.is_closure_fn_mut(fr) => {
@@ -680,11 +671,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 && self.regioncx.universal_regions().defining_ty.is_fn_def())
             || self.regioncx.universal_regions().defining_ty.is_const()
         {
-            return self.report_general_error(&ErrorConstraintInfo {
-                fr_is_local: true,
-                outlived_fr_is_local: false,
-                ..*errci
-            });
+            return self.report_general_error(errci);
         }
 
         let mut diag =
@@ -762,15 +749,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     /// ```
     #[allow(rustc::diagnostic_outside_of_impl)] // FIXME
     fn report_general_error(&self, errci: &ErrorConstraintInfo<'tcx>) -> Diag<'infcx> {
-        let ErrorConstraintInfo {
-            fr,
-            fr_is_local,
-            outlived_fr,
-            outlived_fr_is_local,
-            span,
-            category,
-            ..
-        } = errci;
+        let ErrorConstraintInfo { fr, outlived_fr, span, category, .. } = errci;
 
         let mir_def_name = self.infcx.tcx.def_descr(self.mir_def_id().to_def_id());
 
@@ -789,19 +768,22 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         let outlived_fr_name = self.give_region_a_name(*outlived_fr).unwrap();
         outlived_fr_name.highlight_region_name(&mut diag);
 
-        let err_category = match (category, outlived_fr_is_local, fr_is_local) {
-            (ConstraintCategory::Return(_), true, _) => LifetimeReturnCategoryErr::WrongReturn {
+        let err_category = if matches!(category, ConstraintCategory::Return(_))
+            && self.regioncx.universal_regions().is_local_free_region(*outlived_fr)
+        {
+            LifetimeReturnCategoryErr::WrongReturn {
                 span: *span,
                 mir_def_name,
                 outlived_fr_name,
                 fr_name: &fr_name,
-            },
-            _ => LifetimeReturnCategoryErr::ShortReturn {
+            }
+        } else {
+            LifetimeReturnCategoryErr::ShortReturn {
                 span: *span,
                 category_desc: category.description(),
                 free_region_name: &fr_name,
                 outlived_fr_name,
-            },
+            }
         };
 
         diag.subdiagnostic(err_category);

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -2272,10 +2272,7 @@ impl<D: Decoder> Decodable<D> for EncodedMetadata {
         let len = d.read_usize();
         let mmap = if len > 0 {
             let mut mmap = MmapMut::map_anon(len).unwrap();
-            for _ in 0..len {
-                (&mut mmap[..]).write_all(&[d.read_u8()]).unwrap();
-            }
-            mmap.flush().unwrap();
+            mmap.copy_from_slice(d.read_raw_bytes(len));
             Some(mmap.make_read_only().unwrap())
         } else {
             None