Not able to build using rust 1.26

[JoshuaBatty]

On rust version 1.26 I get the following error. When I updated to Rust 1.27 the error went away.

error[E0599]: no function or associated item named from_bits found for type f64 in the current scope
--> /Users/joshuabatty/.cargo/registry/src/github.jparrowsec.cn-1ecc6299db9ec823/half-1.1.1/src/lib.rs:808:9
|
808 | f64::from_bits(sign | exp | man)
| ^^^^^^^^^^^^^^ function or associated item not found in f64
|
= help: items from traits can only be used if the trait is in scope
= note: the following trait is implemented but not in scope, perhaps add a use for it:
candidate #1: use core::num::Float;

[Rua]

I can confirm, I'm getting the same problem.

[VoidStarKat]

The last pull request changed some mem::transmutes into from_bits, which would've been fine for std, but I didn't realize from_bits only got moved to libcore in 1.27. Changed these back to mem::transmute and published 1.1.2 to prevent such a sudden breaking change.

[userzimmermann]

@starkat99 @JoshuaBatty @Rua FYI: I got the same issue when trying to build https://github.com/paulrouget/servoshell (which has rust-toolchain set to nightly-2017-11-14 -> rustc 1.23.0-nightly), but could basically solve it by just adding extern crate std;

And for my interest: Directly building half 3d17d44 with that fix and same toolchain (out of curiosity) nevertheless resulted in:

> cargo build
   Compiling half v1.1.1 (file:///C:/Users/userz/Projects/rust/half)
warning: unused extern crate
  --> src\lib.rs:36:1
   |
36 | extern crate std;
   | ^^^^^^^^^^^^^^^^^
   |
note: lint level defined here
  --> src\lib.rs:26:32
   |
26 |         trivial_numeric_casts, unused_extern_crates, unused_import_braces, unused_qualifications)]
   |                                ^^^^^^^^^^^^^^^^^^^^

    Finished dev [unoptimized + debuginfo] target(s) in 0.56 secs

Can someone please explain this to me (why something that solves the problem on the other hand produces that warning)? I only have 2 days experience in Rust coding :D