A common situation, where conservative extensions are used,
is with parameters of generic specifications.
For example in a generic specification of lists, the list
specification should not restrict the model class of the
parameter specification.
This is expressed using a conservative generic extension
(GEN-CONS-EXTN)
Another situation is the import of other specifications.
For example, in a specification List of lists with a count function on
lists, we have to refer to
the specification of natural numbers.
In general the intention is that the natural numbers are
protected by List.
Note that a conservative extension should not be used if the extension is a refinement of the extended part. This means that the class of models of the extended part is restricted by the extension.