Enable NoVal checks within Data Dictionary functions
If you use "NoVal" inside a function of a data dictionary, e.g., to check if the input is NoVal, you will get an error in the marker view.
Example of the NoVal usage: if (_V == NoVal) { return false; } return _V;
Resulting error: "Illegal use of NoVal in function ..."
This error is caused by this check: org.fortiss.af3.expression.language.constraint.FunctionDefinitionConstraintChecker.performIllegalUseOfConstructsCheck()
The first NoVal check was implemented through this commit: 937e2cbf
Sadly, issue 436 of this commit is not documented anymore. Therefore, we do not know why exactly NoVals are not allowed inside functions.
The task would be to dig into the function evaluation and see what happens there with a NoVal. If nothing critical happens, the check can be removed. If there is actual a problem with NoVals (highly likely since otherwise Flo would not have added such a check), it should be checked if this can be prevented and thus the NoVal be enabled.