uniq_mutable.m:021: Error: the inst `unique' may not appear in `:- mutable'
uniq_mutable.m:021:   declarations.
uniq_mutable.m:022: Error: the inst `mostly_unique' may not appear in
uniq_mutable.m:022:   `:- mutable' declarations.
uniq_mutable.m:023: Error: the inst `free' may not appear in `:- mutable'
uniq_mutable.m:023:   declarations.
uniq_mutable.m:024: Error: the inst `dead' may not appear in `:- mutable'
uniq_mutable.m:024:   declarations.
uniq_mutable.m:025: Error: the inst `mostly_dead' may not appear in
uniq_mutable.m:025:   `:- mutable' declarations.