c

name	C#
slug	csharp
version	1.0.1
description	Write robust C# avoiding null traps, async deadlocks, and LINQ pitfalls.
metadata	{"clawdbot":{"emoji":"💜","requires":{"bins":["dotnet"]},"os":["linux","darwin","win32"]}}

Quick Reference

Topic	File
Null reference, nullable types	nulls.md
Async/await, deadlocks	async.md
Deferred execution, closures	linq.md
Value vs reference, boxing	types.md
Iteration, equality	collections.md
IDisposable, using, finalizers	dispose.md

Critical Rules

• ?. and ?? prevent NRE but ! overrides warnings — still crashes if null
• .Result or .Wait() on UI thread — deadlock, use await or ConfigureAwait(false)
• LINQ is lazy — query.Where(...) doesn't execute until iteration
• Multiple enumeration of IEnumerable — may re-query database, call .ToList() first
• Closure captures variable, not value — loop variable in lambda captures last value
• Struct in async method — copied, modifications lost after await
• String comparison culture — StringComparison.Ordinal for code, CurrentCulture for UI
• GetHashCode() must be stable — mutable fields break dictionary lookup
• Modifying collection while iterating — throws, use .ToList() to iterate copy
• decimal for money — float/double have precision loss
• readonly struct prevents defensive copies — use for performance
• sealed prevents inheritance — enables devirtualization optimization