Rust Unsafe Keyword

Cluster focuses on debates about Rust's `unsafe` keyword, including its meaning, whether it compromises overall safety, its role in building safe abstractions, and necessity for low-level code.

➡️ Stable 0.7x Programming Languages
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#6028
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Keywords

ANYONE e.g CPU GC IMO github.com API IO unsafe safe code constructor rust language safety languages stdlib memory

Sample Comments

steveklabnik Aug 3, 2020 View on HN

It's not possible, because unsafe does not turn anything off; unsafe is a superset of safe.

IshKebab Dec 16, 2023 View on HN

Not really. `unsafe` is the footgun.

OutOfHere Jun 13, 2024 View on HN

Why not though (for safety-critical code)? How can it be safe with `unsafe`?

kouteiheika May 22, 2023 View on HN

`unsafe` doesn't mean that it's not safe, just that the compiler can't prove that it's safe so the human has to do it manually.

tptacek Nov 24, 2025 View on HN

It's got really not much at all to do with `unsafe`.

briansm May 21, 2025 View on HN

and yet an article about a 'safe' language has code examples full of 'unsafe'... wut.

kinghajj Feb 23, 2018 View on HN

No on both counts, the entire point of "unsafe" is to form safe abstractions around unprovably safe code.

doliveira Jul 19, 2020 View on HN

What's the problem with unsafe? Isn't the whole point to isolate the unsafe behavior into specific parts of the code?

jdub Jul 19, 2020 View on HN

There's necessary and well-encapsulated `unsafe` code in the standard library. It's a tool.

Animats Nov 28, 2016 View on HN

No. As soon as there's unsafe code, there's the possibility of safe code misusing the unsafe code to create unsafe behavior. One would like to have un-abusable unsafe code, but the language does nothing to guarantee that.