offset_of

1 files changed, 5 insertions, 2 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/step.rs b/compiler/rustc_const_eval/src/interpret/step.rs
index 9a366364e76..4ed83f1db0e 100644
--- a/compiler/rustc_const_eval/src/interpret/step.rs
+++ b/compiler/rustc_const_eval/src/interpret/step.rs
@@ -280,10 +280,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 self.write_immediate(*val, &dest)?;
             }
 
-            NullaryOp(null_op, ty) => {
+            NullaryOp(ref null_op, ty) => {
                 let ty = self.subst_from_current_frame_and_normalize_erasing_regions(ty)?;
                 let layout = self.layout_of(ty)?;
-                if layout.is_unsized() {
+                if let mir::NullOp::SizeOf | mir::NullOp::AlignOf = null_op && layout.is_unsized() {
                     // FIXME: This should be a span_bug (#80742)
                     self.tcx.sess.delay_span_bug(
                         self.frame().current_span(),
@@ -294,6 +294,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let val = match null_op {
                     mir::NullOp::SizeOf => layout.size.bytes(),
                     mir::NullOp::AlignOf => layout.align.abi.bytes(),
+                    mir::NullOp::OffsetOf(fields) => {
+                        layout.offset_of_subfield(self, fields.iter().map(|f| f.index())).bytes()
+                    }
                 };
                 self.write_scalar(Scalar::from_target_usize(val, self), &dest)?;
             }