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# Good catch — you’re right.
- URL: https://huizhou92.com/good-catch-youre-right/
- Published: 2026-03-09T09:57:45.000Z
- Updated: 2026-03-09T09:57:45.000Z
- Description: My general point about errors.Is and wrapped sentinel errors still stand, but io.EOF is a special case. The io docs explicitly say that…
- Author: huizhou92
- Tags: #Migrated-1788833207488, #Import 2026-09-08 02:07

Good catch — you’re right.

My general point about errors.Is and wrapped sentinel errors still stand, but io.EOF is a special case. The io docs explicitly say that Read must return io.EOF itself, not a wrapped form, because callers often compare it with ==.

So io.EOF was a poor example there. I’ve updated the demo to use a different sentinel error and will call out io.EOF as an exception.

Thanks for pointing it out.