%Warning-HIERBLOCK: t/t_hier_block1_bad.v:15:8: Top module illegally marked hierarchical block, ignoring marking
                                              : ... In instance t
                    ... Suggest remove verilator hier_block on this module
   15 | module t ( 
      |        ^
                    ... For warning description see https://verilator.org/warn/HIERBLOCK?v=4.201
                    ... Use "/* verilator lint_off HIERBLOCK */" and lint_on around source to disable this message.
%Error: t/t_hier_block1_bad.v:44:32: Modport cannot be used at the hierarchical block boundary
                                   : ... In instance t.i_sub1
   44 | module sub1 (byte_ifs.receiver in, byte_ifs.sender out); /*verilator hier_block*/ 
      |                                ^~
%Error: t/t_hier_block1_bad.v:44:52: Modport cannot be used at the hierarchical block boundary
                                   : ... In instance t.i_sub1
   44 | module sub1 (byte_ifs.receiver in, byte_ifs.sender out); /*verilator hier_block*/ 
      |                                                    ^~~
%Error: Exiting due to