Merge pull request #19726 from lnicola/sync-from-rust

Sync from downstream again

1 files changed, 5 insertions, 5 deletions

diff --git a/compiler/rustc_mir_transform/src/check_alignment.rs b/compiler/rustc_mir_transform/src/check_alignment.rs
index 5115583f37c..8f88613b79f 100644
--- a/compiler/rustc_mir_transform/src/check_alignment.rs
+++ b/compiler/rustc_mir_transform/src/check_alignment.rs
@@ -6,7 +6,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_session::Session;
 
-use crate::check_pointers::{BorrowCheckMode, PointerCheck, check_pointers};
+use crate::check_pointers::{BorrowedFieldProjectionMode, PointerCheck, check_pointers};
 
 pub(super) struct CheckAlignment;
 
@@ -19,15 +19,15 @@ impl<'tcx> crate::MirPass<'tcx> for CheckAlignment {
         // Skip trivially aligned place types.
         let excluded_pointees = [tcx.types.bool, tcx.types.i8, tcx.types.u8];
 
-        // We have to exclude borrows here: in `&x.field`, the exact
-        // requirement is that the final reference must be aligned, but
-        // `check_pointers` would check that `x` is aligned, which would be wrong.
+        // When checking the alignment of references to field projections (`&(*ptr).a`),
+        // we need to make sure that the reference is aligned according to the field type
+        // and not to the pointer type.
         check_pointers(
             tcx,
             body,
             &excluded_pointees,
             insert_alignment_check,
-            BorrowCheckMode::ExcludeBorrows,
+            BorrowedFieldProjectionMode::FollowProjections,
         );
     }