$CASE(...) with no default case
The $CASE function can be written without a default case, as in:
set x = $case(someVar, "foo": val1, "bar": val2)
However, this means that if, in the above example, the value of x is neither "foo" nor "bar", the resulting value will be undefined.
While it can happen that the tested variable only has a certain set of possible values, it is preferred to always have a default case; for instance:
set x = $case(someVar, "foo": val1, "bar": val2, : val3)
This issue may lead to false positives if the set of possible values is indeed limited; such a scenario is not detected.