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The get_last_error() snippet shows LAST_ERROR as being a static mut (which IIRC requires unsafe access as it's not thread-safe). But the parse_mappings() snippet shows safe access to LAST_ERROR using an API that clearly indicates it's not just an Option. I assume that at this point it's actually a std::thread::LocalKey.

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Thanks for the heads up. It used to be a `thread_local!`, but switching to a `static mut` resulted in smaller code size. I just forgot to update the code snippet in the article.

> which IIRC requires unsafe access as it's not thread-safe

Yes, and also has no guarantees against mutably aliasing and re-entry.

Note that wasm currently has no shared memory threading (just message passing via FFI through JS and workers), so thread-safety isn't an issue to be wary of here, just re-entry.

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