[dorfsmay]

Interesting... I'm a newbie at Rust, and expected y to be a float, because of the division.

But it turns out

    let x = 11;
    let y = 11/2;

==> y = 5 Given how type safety is important to Rust, I expected this to panic rather than do an automatic cast.

[masklinn]

There is no type safety issue, and there is no cast. Div on integral types is explicitly implementing as an integer/truncating division: https://doc.rust-lang.org/src/core/ops/arith.rs.html#436-452

There would be no type-safety issue or cast if it were implemented as a real division either, incidentally.

There is room to argue Div should not have been implemented at all on integral types (as in Haskell where integer division is a separate operation entirely), but that's a completely different issue.