Convertion of negative f64 to u64.

[aslpavel]

I tried this code:

let v: f64 = -10.0;
println!("{}", v as u64);
let v: f32 = -10.0;
println!("{}", v as u64);

I expected to see this happen:
Should print

0
0

Instead, this happened:
Stable: 1.43.1

140731856997200
0

Beta channel
Build using the Beta version: 1.44.0-beta.4
(2020-05-23 02c25b3)

1
0

This one is actually correct. Sorry if it has been fixed, I have not found bug report for this, so I've decided to create this one.
Nightly channel
Build using the Nightly version: 1.45.0-nightly
(2020-05-31 5fd2f06)

0
0

[sfackler]

This is #10184

[aslpavel]

I thought #10184 was about NaN, Inf and ect. This one is a normal float as returned by f64::classify(). Plus behavior for f32 is actually correct.

[sfackler]

It is about any out of bounds value.

[ehuss]

As you've noticed, this has changed in 1.45. This is part of #71269, so that both values return 0. The new rules are documented at https://doc.rust-lang.org/nightly/reference/expressions/operator-expr.html#semantics.

[RalfJung]

Plus behavior for f32 is actually correct.

That's just pure chance. Behavior is undefined in both cases (until #71269). When behavior is undefined, looking at what the final executable does is meaningless.

I think this issue should be closed, it is a duplicate of #10184.

[aslpavel]

I see, Thank you!