In reply to dave_59:
Hi Dave,
many thanks for your reply.
Did you try with Icarus? I got this result after changing '{} to {} on EDA playground:
[2021-09-29 10:22:17 EDT] iverilog ‘-Wall’ ‘-g2012’ design.sv testbench.sv && unbuffer vvp a.out
design.sv:21: internal error: I don’t know how to elaborate(ivl_type_t) this expression: {struct_xyz, struct_abc}
design.sv:21: assert: elaborate.cc:2313: failed assertion !is_constant_
Aborted (core dumped)
Exit code expected: 0, received: 1
Done
Compile options are -Wall and -g2012 for Icarus 0.10.