CallStack (from HasCallStack):
  error, called at libraries/bytestring/Data/ByteString/Internal.hs:184:20 in bytestring-0.10.8.1:Data.ByteString.Internal
Test suite regression-tests: FAIL
Test suite logged to: dist/test/ghc-syb-utils-0.2.3.2-regression-tests.log
0 of 1 test suites (0 of 1 test cases) passed.
builder for ‘/nix/store/skgag5jpv04k5sjfb6q3zaksfz7hgnrd-ghc-syb-utils-0.2.3.2.drv’ failed with exit code 1
cannot build derivation ‘/nix/store/45akmsbhz8k3z5463a9a5wma61qzngbk-ghc-8.0.2-with-packages.drv’: 1 dependencies couldn't be built
building path(s) ‘/nix/store/hplmxsv3napzkqb0336q6yk7dlr9gcq8-gitignore-061c5c7’
killing process 5576
cannot build derivation ‘/nix/store/zqh7bgqnw9gvv7ds8j205ipd0a4hbzkn-baseEnv.drv’: 1 dependencies couldn't be built
error: build of ‘/nix/store/zqh7bgqnw9gvv7ds8j205ipd0a4hbzkn-baseEnv.drv’ failed