(internal compiler error: unprintable span)

[hank-der-hafenarbeiter]

When running "cargo test" on this code (reproducable for me when checking out the compiler_bug branch). The compiler outputs:

 Compiling SFCodec v0.1.0 (file:///home/kevin/Projects/Rust/SFCodec)
<std macros>:5:4: 84:20 error: mismatched types:
 expected `bool`,
    found `u8`
(expected bool,
    found u8) [E0308]
(internal compiler error: unprintable span)
src/utils.rs:84:9: 84:57 note: in this expansion of assert! (defined in <std macros>)
<std macros>:5:4: 84:20 help: run `rustc --explain E0308` to see a detailed explanation
error: aborting due to previous error
Could not compile `SFCodec`.

To learn more, run the command again with --verbose.

This is the corresponding code snipped:

fn test_byte_and_back() {
     extern crate rand;
     use self::rand::{thread_rng, Rng};

     let mut rng = thread_rng();
     for i in 0..20 {
         let mut num:u8 = 0;
         for i in 0..8 {
             num = rng.gen();
          } 

         assert!(num, bools_to_byte(byte_to_bools(num)));             //line 84
      }
 } 

rustc --version --verbose:

 rustc 1.6.0 (c30b771ad 2016-01-19)
 binary: rustc
 commit-hash: c30b771ad9d44ab84f8c88b80c25fcfde2433126
 commit-date: 2016-01-19
 host: x86_64-unknown-linux-gnu
 release: 1.6.0

[nagisa]

Works fine in both of

rustc 1.8.0-nightly (0ef8d4260 2016-02-24)
rustc 1.9.0-nightly (d31d8a9a9 2016-03-04)

[wesleywiser]

Seems like a duplicate of #28308

[Mark-Simulacrum]

I get the following. This isn't an ICE, so I'm going to go ahead and close. Please reopen if there's actually something wrong here!

error[E0308]: mismatched types
  --> src/utils.rs:84:9
   |
84 |         assert!(num, bools_to_byte(byte_to_bools(num)));
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected bool, found u8
   |
   = note: this error originates in a macro outside of the current crate