{"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"//"}]}
                // tag_val = variant_index_relative + niche_start_val
                // We need to use machine arithmetic when taking into account `niche_start`:
                let tag_layout = self.layout_of(tag_layout.primitive().to_int_ty(*self.tcx))?;