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nullable

3 posts

2026-11-08 csharp csharp-14 dotnet

How to tell the C# nullable analyzer a member is not null when HasValue is true

Put [MemberNotNullWhen(true, nameof(X), nameof(Y))] on the HasValue property itself, naming the members that become non-null. It works for nullable value types and reference types, but the compiler barely checks the getter, ignores base-class members, and never notices when the state changes afterwards. Verified on .NET 10 SDK 10.0.302 and .NET 11 RC3.

2026-10-28 errors csharp csharp-14

Fix: [MemberNotNull] has no effect on a static factory method and CS8618 still fires

CS8618 is checked when the constructor exits, and [MemberNotNull] on a static method is silently ignored for instance members. Pass the values into a private constructor instead.

2026-07-20 errors csharp csharp-14

Fix: CS8618 "Non-nullable property must contain a non-null value when exiting constructor" in C#

CS8618 means a non-nullable field or property was not initialized by the time the constructor finished. Set it in the constructor, give it a default, mark it required, or make it nullable.