{"ast_node_type":"other","tokens":[{"end":50,"kind":"keyword","start":0,"text":"ecx.write_immediate(filename,"}]}
    ecx.write_immediate(filename, &filename_field)
        ecx.project_fields(&location, [0, 1, 2].map(FieldIdx::from_u32)).unwrap();
        .expect("writing to memory we just allocated cannot fail");