csharp-conventions

name	csharp-conventions
description	C# code conventions covering .NET 8+/C# 12, nullable reference types, Roslyn analyzers, xUnit, record types, async/await discipline, and dependency security. Load when writing or reviewing C# code.

• .NET 8+ C# 12, file-scoped namespaces, primary constructors, <Nullable>enable</Nullable>.
• Formatting: dotnet format + Roslyn analyzers, <TreatWarningsAsErrors>true</TreatWarningsAsErrors>.
• Style enforcement: .editorconfig for consistent rules across team. Use an analyzer set (e.g., StyleCop.Analyzers or Roslynator).
• Testing: xUnit with [Theory]/[InlineData], an assertion library (e.g., FluentAssertions), a coverage tool (e.g., coverlet) at 80%+.
• Benchmarking: a benchmark harness (e.g., BenchmarkDotNet) for performance testing — never Stopwatch loops.
• record types for immutable data, required properties, pattern matching in switch expressions.
• Async: async/await throughout — never .Result or .Wait(), ValueTask for hot paths, avoid deadlocks.
• Security: dotnet list package --vulnerable for CVE scanning. Zero tolerance for critical/high.
• Dependencies: NuGet PackageReference, commit packages.lock.json, Directory.Build.props for shared config.
• Collection expressions ([1, 2, 3]), required modifier, raw string literals for multi-line.
• Anti-patterns: dynamic, object params, unguarded catch (Exception), #pragma warning disable.