  Error evaluating generator expression:

    \$<TARGET_POLICY:NOT_A_POLICY>

  \$<TARGET_POLICY:prop> may only be used with a limited number of policies.
  Currently it may be used with the following policies:

   \* CMP0003
   \* CMP0004
   \* CMP0008
   \* CMP0020
   \* CMP0021
   \* CMP0022
