Segfault when passing a parameter to a reference to input

[Angus-Bethke-Bachmann]

Describe the bug
A Segfault occurs when passing a parameter to a reference to input.

To Reproduce
Steps to reproduce the behavior:

TYPE EnumType : (
        red,
        green,
        blue
    );
END_TYPE

FUNCTION fnReferenceTo : EnumType
VAR_INPUT
    inVar	: Reference To EnumType;
END_VAR
    fnReferenceTo := inVar;
END_FUNCTION

FUNCTION main
VAR
    outVarReferenceTo : EnumType;
END_VAR
    outVarReferenceTo := fnReferenceTo(blue);
END_FUNCTION

Expected behavior
There shouldn't be a segfault. A validation error should be present in the case of a invalid scenario, and it should work if the scenario is valid.