Custom error types in Rust require you to implement Display - and that's where most tutorials gloss over the details.
A long Sunday session working through the deeper Rustlings error handling exercises: defining a custom DoubleError unit struct, implementing the Error trait, then implementing Display so the compiler stops complaining, and understanding why Box(dyn Error) is the practical choice when you're mixing error types. We also revisit the double-first problem with the proper generic error approach, and work through several more Rustlings exercises as the session progresses.
⏱ Chapters
0:00 Intro music (skip ahead)
6:00 Session start - recapping double-first and where we left off
13:55 Defining custom error types - DoubleError unit struct
30:21 Implementing the Error trait
40:35 Implementing Display for custom errors
46:58 Box(dyn Error) for mixed error types
53:06 Wrapping errors with map_err
1:00:42 More Rustlings error handling exercises
1:14:43 Iterating on the solution
1:32:45 Continued exercises and wrap-up
#Rust #RustLang #Rustlings
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Watch live: https://twitch.tv/lorduhuru
