New video on Dissecting the Code YouTube Channel: "How LINQ works?" - youtu.be/hFKCOeUfZaA?... To understand LINQ we should understand iterator blocks. And this is what I'm covering for almost 20 minutes! :)

PerfView can record all managed exceptions in all processes system-wide thanks to the .NET ETW provider, with callstacks. I built a viewer for these .etl files:

Next video on Dissecting the Code channel. This time I cover .NET 10 performance improvements around de-abstracting the delegates. In .NET 10, the LINQ Any method can easily outperform a manual loop over a list! Awesome job, .NET team! youtu.be/-h5251IWv-Y?... And, as always, thanks for watching!

Another video on Dissecting the Code YouTube channel: "ConfigureAwait best practices". I feel we have a cargo cult on using ConfigureAwait without thinking too much. youtu.be/bUHQeY-DlBc?...

Do you know that just changing the C# langversion might affect performance? The code generation for method group conversion has changed in C# 11 to avoid allocations in certain cases.

New video on Dissecting the Code YouTube channel: ".NET 10 De-Abstraction in Action", that covers how .NET 10 almost completely eliminates the abstraction penalty when iterating over interfaces. #dotnet10, #performance

TIL that dotnet/runtime github repo has an awesome bot for running the benchmarks to compare the before and after! Here is an example:

Do you know that .NET 10 massively reduces the overhead of using any built-in collections via interfaces (yes, not only for arrays)? Iterating a list via IList<T>, or dictionary via 'IDictionary<K,V>', etc., now has almost zero abstraction penalty!

I'm writing another book, and the first few chapters are available through Manning Early Access now! For 50% off! hubs.la/Q03Q9PGP0 More details, and the story of how I came to write it, are on my blog at ericlippert.com/2025/10/30/i... It feels great to be writing again after a long break. :)

I want to fail the build on compiler warnings, but keep the diagnostics warnings as warnings. One option that I've found is to set 'TreatWarningsAsErrors' to true, and set 'CodeAnalysisTreatWarningsAsErrors' to false. Is there a better way? /cc: @jaredpar.bsky.social, @terrajobst.net

New blog post: In 2021 I found an invisible memory leak in a tool (VS Code) that I have never used. Impossible? Easy: randomascii.wordpress.com/2025/10/09/f...

New video on Dissecting the Code YouTube Channel. This time, it's about Parallel Stacks - my very favorite @visualstudio.com feature that you probably are not using enough! I can't even count how many times it helped me production incidents investigations! youtu.be/Z5mN0VCB-KA?...

Hey #dotnet people. First milestone for Dissecting the Code YouTube channel - 1k subscribers! Thanks a lot everyone for your support and warm feedback that I'm getting!

After a short break I'm back with the new video on Dissecting the Code YouTube channel. This time its all about ConfigureAwait, why we ended up having it and how it works under the hood! #dotnet folks, please share! I'll really appreciate it! youtu.be/RZsLA_R8i9s?...

Egor landed yesterday a great document about C# "Unsafe code best practices" https://github.com/dotnet/docs/blob/main/docs/standard/unsafe-code/best-practices.md 📜 Even if you think you know them, it is a good read as a reminder! 😎 #dotnet #csharp

Hey #dotnet folks! Please share latest deep-dive video to spread the knowledge about async internals and tips&tricks on debugging .NET code! Your support means the world! /cc: @scott.hanselman.com, @ardalis.com, @terrajobst.net, @migueldeicaza.bsky.social and every other member of .net community!

Hey guys. Async methods might be scary for some, but they're not that complicated if you can debug the async machinery to understand how they work! This is exactly what I did in the last video - "Let's debug async/await in C#". youtu.be/oHKyzgGjKHQ?...

Hey #dotnet community! Please share and let's simplify the way we deal with resources in .NET! /cc: @migueldeicaza.bsky.social, @scott.hanselman.com and other folks, I love to discuss this topic! You might disagree with my take! But its time to reconsider some old patterns.

Posted another episode on YouTube: "The way Dispose Pattern Should Be Implemented". It’s time to reconsider the Dispose Pattern and abandon Dispose(bool disposing) nonsense. Let’s move to a simpler approach and never mix managed and native resources. youtu.be/E6tQDczhrUM?...

Hey @davidfowl.com, @scott.hanselman.com, @jaredpar.bsky.social, @terrajobst.net and other #dotnet community members! Could you please share this tweet about how to unlock most of the C# productivity features even targeting .NET Framework or .netstandard2.0. Appreciate your support!

Posted another episode on YouTube: "Unlocking Modern C# Features Targeting .NET Framework". Quite a few devs limit themselves with C# 7.3 when they target full framework or .netstandard2.0. You still can leverage most of the latest C# features in this case. youtu.be/5eNtdj68qW4?...

How to Find Public Symbols That Can Be Internal Using Roslyn #dotnet #roslyn https://www.meziantou.net/how-to-find-public-symbols-that-can-be-internal-using-roslyn.htm?utm_medium=social&utm_source=bluesky

Hey #dotnet people! Just published another episode on Dissecting the Code channel: How Google Broken the Internet and Why It Took 3 Hours to Recover? It's about null pointer bugs, retry logic and a bit of .NET Aspire used for visualizing the metrics. Please share and sub!

New in MSBuild Structured Log Viewer: Project Reference Graph New tab that shows the project graph layered by project "height". Each project only references projects above it. Clicking a project highlights all directly referenced projects above, and all projects below it that reference this one.

try ref12.io/net472

Name all the ways this line can cause a NullReferenceException: if (x == null) { ... }

Hey friends, my YouTube channel is 18 YEARS OLD today! Please like and subscribe ;) youtube.com/shanselman

Hey #dotnet people! Just published another episode on Dissecting the Code YouTube channel: “Shooting yourself in a foot with the finalizers”. Crashes due to NullReferenceException, race conditions, constructors that finish before the finalizers, and all the fun stuff! youtu.be/Wh2Zl1d57lo?...

TIL about ValueTask.Preserve() helper method that returns a value task that may be used at any point in the future. ValueTasks are tricky and they can't be stored in a field, or awaited multiple times. Preserve "fixes" that by allocating Task<T> under the hood.

New video: Managing Native Resources in .NET. Have you ever think, why we’re not using a struct for managing resources? It should be more efficient, right? Icover what will happen and why we should use the building blocks like SafeHandle. #dotnet youtu.be/DUgtC0OZMtA

Hey #dotnet folks. Do you ever used (or needed) a debug version of a nuget package? The package has only the managed library, no native code, no executables. Is there a use case for that?

Hey #dotnet and other folks. Another quite exciting news: I've been mentoring colleges at MSFT for quite some time and now I'm available as a mentor at mentor.sh platform. Here is my profile: mentor.sh/mentors/Serg... Will be happy to be your mentor and learn from each other!

Hey #dotnet people:) Just published another episode on Dissecting the Code YouTube channel - "Can Tiered Compilation Cause Memory Leaks in .NET". This video is about a change in behavior between full framework on .net 9 in respect to GCInfo and how it affect memory usage.

Your msbuild log view tool is amazing to the point that it should be the *default* way to view detailed build logs in Visual Studio: msbuildlog.com Too many people miss out on important details because it's just not visible otherwise in the build output window.

Just added a rule to ErrorProne.NET to detect simple recursive calls. This may sound too simplistic, but I've seen such code being checked in by an accident. And I've faced StackOverflowException because of that in my tests before myself as well.

Ran into the situation again where updating VS broke incremental builds, because a different compiler version is now being stamped into the embedded PDB, invalidating all caches and resulting in different PE file bytes from identical sources. Glad I invested in the fancy PE parser and differ!

Hey #dotnet people:) Just published another episode on Dissecting the Code YouTube channel - "Dissecting Memory Leaks in .NET". How global events, hidden static collection and timers can cause memory leaks and the ways to avoid it. Link in the comment below.

Totally agree!

This article is spot on! Reinvent the Wheel: endler.dev/2025/reinven...

Hey #dotnet people! I've launched my YouTube channel: "Dissecting the Code". It's going to be very similar to my blog with a lot of deep dives into #dotnet, #csharp etc. I've already published the first two videos: ➡️ Episode 0: What You'll Learn Here ➡️ Episode 1: Dissecting Variable Lifetime

I don't tweet enough about how amazing the Ultra profiler is: github.com/xoofx/ultra

Just had a surprising MethodMissingException in tests without changing something (as far as I know, but 🤷). Found this post by @steplyakov.bsky.social which helped me understanding the issue. I haven't solved it yet in my code, but I will... Thanks! sergeyteplyakov.github.io/Blog/csharp/...

Do you know that CA2241 analyzer (for correct args to formatting methods) is very extensible? It supports: * built-in methods * StringSyntaxAttribute * Methods listed in .editorconfig Try to run it in your codebase, you might be surprised, how many violations do you have!

I just realized what causes me the most burnout at work. It's when management doesn't realize how much tech debt I'm paying off and how much I'm helping people and the ecosystem. All they see is that my tasks aren't progressing, so they start tightening the screws and micromanaging.

Ok, here is a thing. "We all know" that a managed instance can be collected during the method call. But do you know that an instance can be GCed **before** the instance method is called? This works in Release mode only due to the tracking the JIT does via GCInfo. #dotnet

Hot take: in some cases it is useful to profile an app in debug mode. Was helping in a performance analysis and it was not clear where the time is spent exactly. Re-ran profiler in debug build to see that it was a property getter that was used in a hot loop!

`dotnet run file.cs` is coming: Allows running C# source files with no need for an explicit backing project. We call these file-based programs (as opposed to project-based programs). github.com/dotnet/sdk/b...

I haven't written a blog post in a long time! Bridging the Gap: The Future of Aspire medium.com/@davidfowl/b...

Blogged: Finalizers are tricker than you might think. Part 2. sergeyteplyakov.github.io/Blog/2025/03... This is the second part of the series where I really trying to scare you of dealing with native resources. Let's see if I succeed :) #dotnet

Just FYI. If you need to check if a char is within a string, using 'str.IndexOf(c) != -1' is way more efficient than using 'str.Contains(c)' which is a call to 'Enumerable.Contains(string, c)'. Actually the IndexOf version is way more efficient! (the results for full framework)