gistfile1.txt

$ xargo build --example hello
   Compiling core v0.0.0 (file:///home/jonathan/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libcore)
    Finished release [optimized + debuginfo] target(s) in 18.44 secs
    Updating git repository `https://github.com/rust-lang-nursery/compiler-builtins`
   Compiling compiler_builtins v0.1.0 (https://github.com/rust-lang-nursery/compiler-builtins#0ba07e49)
    Finished release [optimized + debuginfo] target(s) in 3.3 secs
   Compiling demo v0.1.0 (file:///home/jonathan/Documents/programming/demo)
   Compiling cortex-m-rt v0.2.5
   Compiling r0 v0.2.2
   Compiling vcell v0.1.0
   Compiling cortex-m-semihosting v0.1.3
   Compiling aligned v0.1.1
   Compiling cortex-m v0.2.12
   Compiling volatile-register v0.2.0
error: internal compiler error: librustc_metadata/cstore_impl.rs:131: get_optimized_mir: missing MIR for `DefId(7/0:8 ~ cortex_m_rt[bbea]::lang_items[0]::start[0])`

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.25.0-nightly (51b0b3734 2018-01-12) running on x86_64-unknown-linux-gnu

thread 'rustc' panicked at 'Box<Any>', librustc_errors/lib.rs:508:9
note: Run with `RUST_BACKTRACE=1` for a backtrace.

error: Could not compile `demo`.

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