Go 1.26: Recursive Type Constraints Explained

In this video, we will look at recursive type constraints in Go 1.26. If you're interested in the new errors.AsType function, feel free to check out this video: https://youtu.be/vIt-gutcWjo 📝 Description Stop relying on the empty `any` interface and risky runtime type assertions—Go 1.26 finally introduces recursive type constraints, bringing much-needed compile-time safety to advanced generics. In this practical tutorial, we explore what F-bounded polymorphism means for Go, why referencing a generic type within its own constraint previously triggered compiler errors, and how to successfully use this new feature to build types that operate on their own kind. By the end, you will know exactly how to leverage recursive constraints to build robust, strongly-typed data structures without sacrificing safety. Here's what you will learn: • Understand what recursive type constraints are and how they allow a generic interface to reference itself directly • See why the old workaround of using `any` forced developers into unsafe type assertions that risked runtime panics instead of catching bugs at compile time • Walk through a practical example of building a generic, strongly-typed doubly linked list using the new `Node[T Node[T]]` syntax • Learn the mechanics of implementing these constraints, including why explicit dereferencing is required to access methods and how to use value receivers to avoid unnecessary double pointers • Discover how this update guarantees that callback methods receive fully typed concrete values, entirely eliminating the need to unwrap empty interfaces ⏳ Timestamps: 00:00 - Introduction 00:15 - What is this? 01:03 - Use Case 09:38 - Outro 👋 Hey there! If you are new to this channel: Hey 👋 my name is Flo and I am a professional software engineer with a passion for coding in Golang, TypeScript, JavaScript, and Rust. This channel is where I share that passion and dive into the exciting world of software engineering. 📨 Support and Connect! Become a member. https://www.youtube.com/@FloWoelki/membership Discord: https://discord.gg/TnA7drJ X / Twitter: https://x.com/FlorianWoelki LinkedIn: https://www.linkedin.com/in/florian-woelki/ GitHub: https://github.com/FlorianWoelki 📝 Copyright Notice The original Go Gopher was designed by Renée French (Source: https://go.dev/blog/gopher License details: https://creativecommons.org/licenses/by/4.0/). The gopher appearing in this video and thumbnail has been modified from the original design and is based on an illustration from Maria Letta's free-gophers-pack (Source: https://github.com/MariaLetta/free-gophers-pack License: CC0 1.0 Public Domain https://creativecommons.org/publicdomain/zero/1.0/). #go #recursivetypeconstraints #generics