Internal Error: Sub-system: HDD, File: /quartus/h/hdb_if_json_sys.h, Line: 226

Description

Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 19.1, you may see this error during the synthesis stage of compilation.

Resolution

To work around the problem, remove instance assignments that have "auto_fab_0|*" as in the target (-to) field from the QSF (and other scripts sourced by the QSF) file. 

This problem is fixed starting with the Intel® Quartus® Prime Pro Edition Software version 20.1.