Change ty.kind to a method

compiler/rustc_mir/src/interpret/operand.rs

@@ -662,7 +662,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let discr_val = self.cast_from_scalar(tag_bits, tag_layout, discr_layout.ty);
                 let discr_bits = discr_val.assert_bits(discr_layout.size);
                 // Convert discriminant to variant index, and catch invalid discriminants.
-                let index = match op.layout.ty.kind {
+                let index = match *op.layout.ty.kind() {
                     ty::Adt(adt, _) => {
                         adt.discriminants(*self.tcx).find(|(_, var)| var.val == discr_bits)
                     }