cannot cast between signed <-> unsigned

[burrbull]

Bug?

  let i = -1000i32;
  let ii =  i32x2::new(i,i);
  let uu =  u32x2::from(ii);

57 |   let uu =  u32x2::from(ii);
   |             ^^^^^^^^^^^ the trait `std::convert::From<packed_simd::Simd<[i32; 2]>>` is not implemented for `packed_simd::Simd<[u32; 2]>`

[gnzlbg]

This is intended behavior, you want let uu: u32x2 = ii.cast(); which is pretty much like as. Note that:

fn main() {
  let i = -1000i32;
  let u =  u32::from(i);
}

also produces the same error. From/Into perform lossless value preserving conversions, but the conversion you want to perform is not value preserving for all values. For primitive types, you could use TryFrom/TryInto which return an Option<u32> with Some or None depending of for the particular value provided the conversion was value-preserving, but for a negative integer conversion into an unsigned integer it will always return None since that is never value preserving. There is a section in the main documentation explaining this, but it basically means that the same rules apply for the vector types and for the primitive types: https://rust-lang-nursery.github.io/packed_simd/packed_simd/#conversions

[burrbull]

Thanks for new docs.

[gnzlbg]

The docs.rs builds are sadly broken (see #110), I'll do a release once that is fixed so that these become more easily discoverable. Right now they are linked in the readme if you need to find these again.