4 files changed, 26 insertions, 24 deletions
diff --git a/compiler/rustc_const_eval/src/errors.rs b/compiler/rustc_const_eval/src/errors.rs
index 6214ce0f511..cc8f3387238 100644
--- a/compiler/rustc_const_eval/src/errors.rs
+++ b/compiler/rustc_const_eval/src/errors.rs
@@ -390,15 +390,6 @@ pub struct LiveDrop<'tcx> {
     pub dropped_at: Option<Span>,
 }
 
-#[derive(LintDiagnostic)]
-#[diag(const_eval_align_check_failed)]
-pub struct AlignmentCheckFailed {
-    pub has: u64,
-    pub required: u64,
-    #[subdiagnostic]
-    pub frames: Vec<FrameNote>,
-}
-
 #[derive(Diagnostic)]
 #[diag(const_eval_error, code = "E0080")]
 pub struct ConstEvalError {
@@ -568,9 +559,10 @@ impl<'a> ReportErrorExt for UndefinedBehaviorInfo<'a> {
 
                 builder.set_arg("bad_pointer_message", bad_pointer_message(msg, handler));
             }
-            AlignmentCheckFailed(Misalignment { required, has }) => {
+            AlignmentCheckFailed(Misalignment { required, has }, msg) => {
                 builder.set_arg("required", required.bytes());
                 builder.set_arg("has", has.bytes());
+                builder.set_arg("msg", format!("{msg:?}"));
             }
             WriteToReadOnly(alloc) | DerefFunctionPointer(alloc) | DerefVTablePointer(alloc) => {
                 builder.set_arg("allocation", alloc);
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index 8b9f0ce9421..e31f4f1f697 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -21,8 +21,8 @@ use rustc_target::abi::{Align, HasDataLayout, Size};
 use crate::fluent_generated as fluent;
 
 use super::{
-    alloc_range, AllocBytes, AllocId, AllocMap, AllocRange, Allocation, CheckInAllocMsg,
-    GlobalAlloc, InterpCx, InterpResult, Machine, MayLeak, Misalignment, Pointer,
+    alloc_range, AllocBytes, AllocId, AllocMap, AllocRange, Allocation, CheckAlignMsg,
+    CheckInAllocMsg, GlobalAlloc, InterpCx, InterpResult, Machine, MayLeak, Misalignment, Pointer,
     PointerArithmetic, Provenance, Scalar,
 };
 
@@ -425,7 +425,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 }
                 // Must be aligned.
                 if M::enforce_alignment(self) && align.bytes() > 1 {
-                    self.check_misalign(Self::offset_misalignment(addr, align))?;
+                    self.check_misalign(
+                        Self::offset_misalignment(addr, align),
+                        CheckAlignMsg::AccessedPtr,
+                    )?;
                 }
                 None
             }
@@ -449,7 +452,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // Test align. Check this last; if both bounds and alignment are violated
                 // we want the error to be about the bounds.
                 if M::enforce_alignment(self) && align.bytes() > 1 {
-                    self.check_misalign(self.alloc_misalignment(ptr, offset, align, alloc_align))?;
+                    self.check_misalign(
+                        self.alloc_misalignment(ptr, offset, align, alloc_align),
+                        CheckAlignMsg::AccessedPtr,
+                    )?;
                 }
 
                 // We can still be zero-sized in this branch, in which case we have to
@@ -460,9 +466,13 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     }
 
     #[inline(always)]
-    pub(super) fn check_misalign(&self, misaligned: Option<Misalignment>) -> InterpResult<'tcx> {
+    pub(super) fn check_misalign(
+        &self,
+        misaligned: Option<Misalignment>,
+        msg: CheckAlignMsg,
+    ) -> InterpResult<'tcx> {
         if let Some(misaligned) = misaligned {
-            throw_ub!(AlignmentCheckFailed(misaligned))
+            throw_ub!(AlignmentCheckFailed(misaligned, msg))
         }
         Ok(())
     }
diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index 240613bdff6..182da84312e 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -15,9 +15,9 @@ use rustc_middle::ty::Ty;
 use rustc_target::abi::{Abi, Align, FieldIdx, HasDataLayout, Size, FIRST_VARIANT};
 
 use super::{
-    alloc_range, mir_assign_valid_types, AllocId, AllocRef, AllocRefMut, ImmTy, Immediate,
-    InterpCx, InterpResult, Machine, MemoryKind, Misalignment, OffsetMode, OpTy, Operand, Pointer,
-    PointerArithmetic, Projectable, Provenance, Readable, Scalar,
+    alloc_range, mir_assign_valid_types, AllocId, AllocRef, AllocRefMut, CheckAlignMsg, ImmTy,
+    Immediate, InterpCx, InterpResult, Machine, MemoryKind, Misalignment, OffsetMode, OpTy,
+    Operand, Pointer, PointerArithmetic, Projectable, Provenance, Readable, Scalar,
 };
 
 #[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
@@ -461,7 +461,7 @@ where
         // We check alignment separately, and *after* checking everything else.
         // If an access is both OOB and misaligned, we want to see the bounds error.
         let a = self.get_ptr_alloc(mplace.ptr(), size, Align::ONE)?;
-        self.check_misalign(mplace.mplace.misaligned)?;
+        self.check_misalign(mplace.mplace.misaligned, CheckAlignMsg::BasedOn)?;
         Ok(a)
     }
 
@@ -477,7 +477,7 @@ where
         // We check alignment separately, and raise that error *after* checking everything else.
         // If an access is both OOB and misaligned, we want to see the bounds error.
         // However we have to call `check_misalign` first to make the borrow checker happy.
-        let misalign_err = self.check_misalign(mplace.mplace.misaligned);
+        let misalign_err = self.check_misalign(mplace.mplace.misaligned, CheckAlignMsg::BasedOn);
         let a = self.get_ptr_alloc_mut(mplace.ptr(), size, Align::ONE)?;
         misalign_err?;
         Ok(a)
@@ -881,8 +881,8 @@ where
             dest_size,
             /*nonoverlapping*/ true,
         )?;
-        self.check_misalign(src.mplace.misaligned)?;
-        self.check_misalign(dest.mplace.misaligned)?;
+        self.check_misalign(src.mplace.misaligned, CheckAlignMsg::BasedOn)?;
+        self.check_misalign(dest.mplace.misaligned, CheckAlignMsg::BasedOn)?;
         Ok(())
     }
 
diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs
index b8cc4e8007e..f734783af64 100644
--- a/compiler/rustc_const_eval/src/interpret/validity.rs
+++ b/compiler/rustc_const_eval/src/interpret/validity.rs
@@ -385,7 +385,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
                 CheckInAllocMsg::InboundsTest, // will anyway be replaced by validity message
             ),
             self.path,
-            Ub(AlignmentCheckFailed(Misalignment { required, has })) => UnalignedPtr {
+            Ub(AlignmentCheckFailed(Misalignment { required, has }, _msg)) => UnalignedPtr {
                 ptr_kind,
                 required_bytes: required.bytes(),
                 found_bytes: has.bytes()