Internal compiler error with lib is built by different rust version.

[sammykim]

Error message is

/home/sammy.kim/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x7f9fccedeea4]
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug
note: try running with RUST_LOG=rustc=1,::rt::backtrace to get further details and report the results to github.com/mozilla/rust/issues
rust: task failed at 'explicit failure', /home/yichoi/rust_stable4/src/librustc/rustc.rc:359
/home/sammy.kim/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4b)[0x7f9fccede65b]
/home/sammy.kim/bin/../lib/librustrt.so(+0x2a249)[0x7f9fcceef249]
/home/sammy.kim/bin/../lib/librustrt.so(upcall_fail+0x198)[0x7f9fccee0458]
/home/sammy.kim/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x10232b)[0x7f9fce95332b]
/home/sammy.kim/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x1022d2)[0x7f9fce9532d2]
/home/sammy.kim/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN3sys12begin_unwind17_7cd364c41f10422f3_06E+0x71)[0x7f9fce89e2e1]
/home/sammy.kim/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x14c264)[0x7f9fce99d264]
/home/sammy.kim/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN7monitor17_bd76f93fc7c7a02f3_06E+0x2cf5)[0x7f9fcd94be45]
/home/sammy.kim/bin/../lib/librustc-c84825241471686d-0.6.so(+0x837004)[0x7f9fcd958004]
/home/sammy.kim/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN4main16_706f4ee7413ae583_06E+0x7e)[0x7f9fcd957c1e]
/home/sammy.kim/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x7f9fccedeea4]
rust: domain main @0x1d00c20 root task failed

[bstrie]

Closing this since I have no idea how to reproduce it and the backtrace doesn't seem especially helpful. @sammykim, feel free to reopen if you're still hitting this.