C# Feature - Nullable reference types

Overview

Nullable reference types use annotations and flow analysis so the compiler can warn when null may violate a reference type contract.

Introduced In

C# 8.0 (2019)

Before

string name = FindName();
Console.WriteLine(name.Length);

After

string? name = FindName();
Console.WriteLine(name?.Length ?? 0);

Gotchas & Best Practices

• Enable nullable context project-wide instead of file by file when possible.
• Treat warnings as design feedback, not just compiler noise.