invalid command name "get_combs"

Description

In the Quartus® Prime Pro Edition Software version 18.0, this error message may be seen after running the write_sdc -expand command on a session that had included the derive_pll_clocks directive. The Timing Analyzer will incorrectly infer the unsupported get_combs collection.

Resolution

To work around this problem, substitute all get_combs for get_nodes in the resulting sdc file after executing the write_sdc -expand command.

This problem is scheduled to be fixed in a future release of the Quartus® Prime Pro Edition Software.