Add flags to thos modifier set, checking that there are no type/term conflicts.
If there are conflicts, issue an error and return the modifiers consisting of
the added flags only. The reason to do it this way is that the added flags usually
describe the core of a construct whereas the existing set are the modifiers
given in the source.
Add flags to thos modifier set, checking that there are no type/term conflicts.
If there are conflicts, issue an error and return the modifiers consisting of
the added flags only. The reason to do it this way is that the added flags usually
describe the core of a construct whereas the existing set are the modifiers
given in the source.
