dotnet-csharp-nullable-reference-types
dotnet-csharp-nullable-reference-types
Nullable reference type (NRT) annotation strategies, migration guidance for legacy codebases, and the most common annotation mistakes AI agents make. NRT is enabled by default in all modern .NET templates (net6.0+), but many existing codebases still need migration.
Cross-references: [skill:dotnet-csharp-coding-standards] for null-handling style, [skill:dotnet-csharp-modern-patterns] for pattern matching with nulls.
Quick Reference: NRT Defaults by TFM
| TFM | <Nullable> default |
Notes |
|---|---|---|
| net8.0+ | enable (in templates) |
New projects have NRT enabled by default |
| net6.0/net7.0 | enable (in templates) |
Same as net8.0 |
| netstandard2.0/2.1 | not set | Must opt in explicitly |
| net48 / older | not set | Must opt in explicitly |
Important: The TFM does not enforce NRT -- the <Nullable>enable</Nullable> MSBuild property does. Legacy projects upgraded to net8.0 may not have it enabled.
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