gistfile2.txt

dap@blinky manta-mreq $ rustc -g test.rs 
dap@blinky manta-mreq $ RUST_BACKTRACE=1 ./test
thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', src/libcore/option.rs:345:21
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
   1: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:70
   2: std::panicking::default_hook::{{closure}}
             at src/libstd/sys_common/backtrace.rs:58
             at src/libstd/panicking.rs:200
   3: std::panicking::default_hook
             at src/libstd/panicking.rs:215
   4: <std::panicking::begin_panic::PanicPayload<A> as core::panic::BoxMeUp>::get
             at src/libstd/panicking.rs:478
   5: std::panicking::continue_panic_fmt
             at src/libstd/panicking.rs:385
   6: std::panicking::try::do_call
             at src/libstd/panicking.rs:312
   7: <T as core::any::Any>::type_id
             at src/libcore/panicking.rs:85
   8: <T as core::any::Any>::type_id
             at src/libcore/panicking.rs:49
   9: <core::option::Option<T>>::unwrap
             at /rustc/fc50f328b0353b285421b8ff5d4100966387a997/src/libcore/macros.rs:11
  10: test::two
             at ./test.rs:14
  11: test::one
             at ./test.rs:8
  12: test::main
             at ./test.rs:3
  13: std::rt::lang_start::{{closure}}
             at /rustc/fc50f328b0353b285421b8ff5d4100966387a997/src/libstd/rt.rs:64
  14: std::panicking::try::do_call
             at src/libstd/rt.rs:49
             at src/libstd/panicking.rs:297
  15: panic_unwind::dwarf::eh::read_encoded_pointer
             at src/libpanic_unwind/lib.rs:87
  16: <std::panicking::begin_panic::PanicPayload<A> as core::panic::BoxMeUp>::get
             at src/libstd/panicking.rs:276
             at src/libstd/panic.rs:388
             at src/libstd/rt.rs:48
  17: std::rt::lang_start
             at /rustc/fc50f328b0353b285421b8ff5d4100966387a997/src/libstd/rt.rs:64
  18: test::two

test.rs

fn main()
{
    one();
}

fn one()
{
    two();
}

fn two()
{
    let x : Option<i16> = None;
    x.unwrap();
}