Mastering Records

Records exist to fix one specific problem: plain classes use reference equality by default, and writing value equality by hand means overriding Equals, GetHashCode, ToString, and the equality operators every single time. In this chapter, we look at exactly what the compiler generates for a record — verified directly against the real decompiled output, not just described — where that convenience genuinely breaks down (mutable records, and equality that doesn't reach into collections), and why the default equality on an ordinary struct is correct but slow. We close with a real BenchmarkDotNet run comparing default struct equality against record struct, proving the reflection cost is real and measurable. What we cover: What a hand-written value equality override actually costs you record vs. plain class: the same default behavior gap from the value types chapter What the compiler actually generates for a record, viewed directly via SharpLab Where records break: mutable properties, and equality that doesn't recurse into collections Why default struct equality uses reflection, and how record struct avoids it — benchmarked Every claim in this video is backed by real, live-run output — no hand-waved numbers. #csharp #dotnet #programming #softwareengineering #csharpperformance #dotnetinternals #benchmarkdotnet #records #jetbrainsrider