I wrote some code in .NET Project on a windows 10 machine with visual studio 2017. The target framework ist 4.5.2. and the used C# version is default (running the csc tool under "C:\Windows\Microsoft.NET\Framework\v4.0.30319" shows C# 5.
I have used a feature from C# 6. The Monadic null checking (https://damieng.com/blog/2013/12/09/probable-c-6-0-features-illustrated). and the compiler doesn't complain about it.
Is that a normal bhaviour or am I missing something? Shouldn't the compiler complain about it?