%Error: t/t_iff.v:64:15: syntax error, unexpected iff, expecting ')' or ',' or or
   64 |    always @(d iff enable == 1) begin
      |               ^~~
%Error: t/t_iff.v:69:35: syntax error, unexpected iff, expecting ')'
   69 |    assert property (@(posedge clk iff enable)
      |                                   ^~~
%Error: Exiting due to