Const assert is not evaluated in const generic unless used

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#1

Given the following code: Rust Playground

It seems that the const assert is not evaluated, and does not cause a panic compile-time error, unless the constant is actually used somewhere.
Is there a reason for this behaviour? Silently ignoring a const assert seems like very odd behaviour. Is this a bug or expected behaviour?

#2

It is expected

Associated constant definitions undergo constant evaluation only when referenced

https://doc.rust-lang.org/reference/items/associated-items.html#associated-constants

I don't know what the reason is, I assume that it's to reduce compile-times when associated constants aren't referenced.