usually, the error was shown if you press on the analyze HDL files in the component editor:
Error: VHDL error at p_component_c.vhd(1): synthesis directive "vhdl_input_version" is not supported File: /data/ts_farm/kentan/2019/October/Forum_qsys_top_level_pro/p_component_c.vhd Line: 1
Error: Ignored construct p_component_c at p_component_c.vhd(16) due to previous errors File: /data/ts_farm/kentan/2019/October/Forum_qsys_top_level_pro/p_component_c.vhd Line: 16
Error: VHDL error at component_c.vhd(1): synthesis directive "vhdl_input_version" is not supported File: /data/ts_farm/kentan/2019/October/Forum_qsys_top_level_pro/component_c.vhd Line: 1
Error: VHDL Use Clause error at component_c.vhd(8): design library "altera_work" does not contain primary unit "p_component_c" File: /data/ts_farm/kentan/2019/October/Forum_qsys_top_level_pro/component_c.vhd Line: 8
Error: VHDL error at component_c.vhd(19): object "discrete_array_t" is used but not declared File: /data/ts_farm/kentan/2019/October/Forum_qsys_top_level_pro/component_c.vhd Line: 19
Error: VHDL error at component_c.vhd(23): object "record_out_t" is used but not declared File: /data/ts_farm/kentan/2019/October/Forum_qsys_top_level_pro/component_c.vhd Line: 23
Error: Ignored construct component_c at component_c.vhd(24) due to previous errors File: /data/ts_farm/kentan/2019/October/Forum_qsys_top_level_pro/component_c.vhd Line: 24
Error: Flow failed:
Warning: Quartus Prime Synthesis was unsuccessful. 8 errors, 0 warnings
Error: Peak virtual memory: 1231 megabytes
Error: Processing ended: Tue Oct 8 10:58:44 2019
Error: Elapsed time: 00:00:04
Error: System process ID: 46096
I will file an enhancement to our engineering on this. Thanks