message: fix for FieldPlacement rename
diff: @@ -324,19 +324,19 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  fields: impl Iterator<Item = InterpResult<'tcx, MPlaceTy<'tcx, Tag>>>,
  ) -> InterpResult<'tcx> {
  match place.layout.fields {
  - layout::FieldPlacement::Array { .. } => {
  + layout::FieldsShape::Array { .. } => {
  // For the array layout, we know the iterator will yield sorted elements so
  // we can avoid the allocation.
  self.walk_aggregate(place, fields)
  }
  - layout::FieldPlacement::Arbitrary { .. } => {
  + layout::FieldsShape::Arbitrary { .. } => {
  // Gather the subplaces and sort them before visiting.
  let mut places =
  fields.collect::<InterpResult<'tcx, Vec<MPlaceTy<'tcx, Tag>>>>()?;
  places.sort_by_key(|place| place.ptr.assert_ptr().offset);
  self.walk_aggregate(place, places.into_iter().map(Ok))
  }
  - layout::FieldPlacement::Union { .. } => {
  + layout::FieldsShape::Union { .. } => {
  // Uh, what?
  bug!("a union is not an aggregate we should ever visit")
  }
  