Unit test crashing with recent rust nightly

My unit tests have been crashing since rustc 1.19.0-nightly (04145943a 2017-06-19) on MacOS.

Previous version do not crash. Later versions do crash with "error: An unknown error occurred"

My project is quite large and contains unsafe code, so this could be a bug that got surfaced by a change in the compiler.

Has anyone experienced similar problems?