sext(concat()) does not translate

[wizard97]

If you do sext(concat(a, b, c)) it will not translate. It appears nested sext()'s and concat() do not translate. The translation fails with something similar to:

E         AttributeError: 
E         Unexpected error during VerilogTranslation!
E         Please contact the PyMTL devs!
E         'Call' object has no attribute '_object'
E         
E         > <unknown>
E         
E         File:      /home/aaron/Code/pymtl-rv64gc/src/core/rtl/frontend/decode.py
E         Model:     Decode_0x32fcb92d0a0d639a
E         Function:  handle_imm
E         Line:      ~125

../../../vc/git-hub/cornell-brg/pymtl/pymtl/tools/translation/verilog_behavioral.py:106: AttributeError