checking package dependencies
compiling StringHead_Empty.bsv
code generation for sysStringHead_Empty starts
Error: "StringHead_Empty.bsv", line 4, column 27: (S0015)
  Bluespec evaluation-time error: stringHead: empty string
  During elaboration of the body of rule `r' at "StringHead_Empty.bsv", line
  3, column 9.
  During elaboration of `sysStringHead_Empty' at "StringHead_Empty.bsv", line
  2, column 8.