Teach and review C# nullable reference types and null-safety. Use for nullable warnings, nullable annotations, null-forgiving operator, required members, null checks, guard clauses, NullReferenceException prevention, DTOs, EF Core entities, ASP.NET Core model binding, public API null contracts, and migration to nullable-enabled C# projects.
Teach and review C# nullable reference types and null-safety. Use for nullable warnings, nullable annotations, null-forgiving operator, required members, null checks, guard clauses, NullReferenceException prevention, DTOs, EF Core entities, ASP.NET Core model binding, public API null contracts, and migration to nullable-enabled C# projects.
metadata
{"short-description":"C# nullable reference type help"}
C# Nullability
Use $csharp-tutor mode=nullability.
Treat all user text after $csharp-nullability as the nullable reference type concept, warning, code review, migration, API contract, or null-safety question. Use the main csharp-tutor skill as the source of truth.
Load these csharp-tutor references when useful:
references/nullability-guidance.md
references/analyzers-guidance.md
references/common-csharp-pitfalls.md
references/style-guidance.md
references/errors-guidance.md
references/api-design-guidance.md
references/versioning-guidance.md
references/official-sources.md
references/source-citation-rules.md
Default to beginner-friendly explanations that distinguish annotations from runtime validation. Treat ! as a last-resort warning suppression, not a normal fix. When reviewing code, separate correctness risks from cleanup and migration tips.
Standalone Guidance
Core rule: Keep the answer centered on the concrete nullability decision, failure mode, or contract.
Avoid: Giving generic C# advice without tying it to the nullability concern.
Minimal example: public required string Email { get; init; }
