$ make RUST_BACKTRACE=1
cfg: version 1.0.0-dev (36cd65f78 2015-03-07) (built 2015-03-07)
cfg: build triple x86_64-unknown-linux-gnu
cfg: host triples x86_64-unknown-linux-gnu
cfg: target triples x86_64-unknown-linux-gnu
cfg: enabling more debugging (CFG_ENABLE_DEBUG)
cfg: host for x86_64-unknown-linux-gnu is x86_64
cfg: os for x86_64-unknown-linux-gnu is unknown-linux-gnu
cfg: good valgrind for x86_64-unknown-linux-gnu is 1
cfg: using CC=gcc (CFG_CC)
cfg: no xelatex found, disabling LaTeX docs
cfg: no pandoc found, omitting PDF and EPUB docs
rustc: x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore
thread '<main>' panicked at 'arithmetic operation overflowed', /home/user/rust/rust/src/libcore/num/wrapping.rs:79
stack backtrace:
   1:     0x7f9ad4ff3cd2 - sys::backtrace::write::h9e965d8be9b2b550QBA
   2:     0x7f9ad5013e8e - panicking::on_panic::h51fc3f9862106e43jHJ
   3:     0x7f9ad4f779ab - rt::unwind::begin_unwind_inner::hc32c38959726123emnJ
   4:     0x7f9ad4f77bf2 - rt::unwind::begin_unwind_fmt::h2ef00b7193aff76eXlJ
   5:     0x7f9ad5013777 - rust_begin_unwind
   6:     0x7f9ad505fc44 - panicking::panic_fmt::h853cbdbe1217d817HXs
   7:     0x7f9ad505bc4d - panicking::panic::ha4fd99f3e70045e3TVs
   8:     0x7f9ad5026b72 - isaac::Isaac64Rng::init::hf83a40450fe4db3bjQb
   9:     0x7f9ad4feada1 - rand::StdRng::new::h2514ecba1532943dktt
  10:     0x7f9ad4feb33e - rand::thread_rng::THREAD_RNG_KEY::__init::h0eee36982b05a9baqyt
  11:     0x7f9ad4f88387 - rand::thread_rng::h90015ba0c9c7acadAxt
  12:     0x7f9ace3c9760 - collections::hash::map::RandomState.Default::default::h25eefa1b57bdf771A0v
  13:     0x7f9ace3c58c7 - terminfo::parser::compiled::parse::h11ff739f201b4042Tya
  14:     0x7f9ace3d3ebd - terminfo::TerminfoTerminal<T>::new::h7917623852747615108
  15:     0x7f9ace3d8338 - stderr::h051750687ebc4643cbc
  16:     0x7f9ad2832482 - diagnostic::EmitterWriter::stderr::h14c78e21bed1aa61exE
  17:     0x7f9ad568b9f7 - run::h8b17fa571f74ea25m6b
  18:     0x7f9ad569d148 - main::hc27fdc8056149569bcd
  19:     0x7f9ad5084a98 - rust_try_inner
  20:     0x7f9ad5084a85 - rust_try
  21:     0x7f9ad5015593 - rt::lang_start::ha0e5132422a05a6ezBJ
  22:     0x7f9ad4b15d64 - __libc_start_main
  23:     0x7f9ad5ae8848 - <unknown>
  24:                0x0 - <unknown>
make: *** [x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/stamp.core] Error 101