Is "as" an uneccesary footgun?
replies(4):
“as” is a good example. Floats are pretty much the only reason PartialEq exists, so why can’t we have a guaranteed-not-NaN-nor-inf type in std and use that everywhere? Why not make wrapping integers a panic even in release mode? Why not have proper dependent types (e.g. to remove bound checks), and proper linear types (to enforce that object destructors always run)?
It’s easy to forget that Rust is not an ideal language, but rather a very pragmatic one, and sometimes correctness loses in favour of some other goals.
Did you read the article? Rust includes overflow checks in debug builds, and then about a dozen methods (checked_mul, checked_add, etc.) which explicitly provide for checks in release builds.
Pragmatism, for me, is this help when you need it approach.
TBF Rust forces certain choices on one in other instances, like SipHash as the default Hasher for HashMap. But again opting out, like opting in, isn't hard.
You can turn those checks on, in release mode, of course: https://doc.rust-lang.org/rustc/codegen-options/index.html#o...
But I think the behavior on overflow is to "panic!()" (terminate immediately)? So -- I guess from my POV I wouldn't in release mode. I just think that tradeoff isn't generally worth it, but again, you can turn that behavior on.
I don't disagree though this point is a little pedantic. I suppose the docs also need an update? See: https://doc.rust-lang.org/std/macro.panic.html
"This allows a *program to terminate immediately* and provide feedback to the caller of the program."
And my point remains, without more, this probably isn't the behavior one wants in release mode. But, yes, also perhaps an even better behavior is turning on checks, catching the panic, and logging it with others.