inconceivable 0.9.0

`inconceivable!` is a macro which closely parallels `std::unreachable`, or `std::panic`. The primary difference is that when this crate is configured with the `ub_inconceivable` option it will emit the `core::hint::unreachable_unchecked` to hint for the compiler to understand a condition should never occur. Generally compiler(s) (the LLVM) assume UB won't happen. This macro offers the "best of both worlds", it provides a solid way of asserting/testing behavior in local builds, but also a way of stripping branches out of final release builds. Please Note: This crate is created purely to inject undefined behavior into stable, safe rust. Systematic usage is unwise, and not recommended.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

extern crate rustc_version;
use rustc_version::version_meta;

fn main() {
    let version_info = match version_meta() {
        Ok(v) => v,
        Err(e) => panic!("could not identify rustc version. error:'{:?}'", e),
    };

    if version_info.semver.major != 1 {
        panic!("presently we only support version 1.X of rustc");
    }

    if version_info.semver.major == 1 && version_info.semver.minor >= 27 {
        // special configuration variable for compiler version 1.27
        // this is when `core::hint::unchecked_unreachable` was
        // stablized.
        println!("cargo:rustc-cfg=RUSTC_VERSION_GE_1_27");
    }
}