Hadrian isn't -Wincomplete-uni-patterns clean
For example
[71 of 96] Compiling Rules.Libffi ( src/Rules/Libffi.hs, /code/ghc/hadrian/dist-newstyle/build/x86_64-linux/ghc-8.6.5/hadrian-0.1.0.0/x/hadrian/build/hadrian/hadrian-tmp/Rules/Libffi.o )
src/Rules/Libffi.hs:187:61: warning: [-Wincomplete-uni-patterns]
Pattern match(es) are non-exhaustive
In a lambda abstraction:
Patterns not matched:
[]
[_]
(_:_:_:_)
|
187 | fmap (libffiPath -/-) ["Makefile.in", "configure" ] &%> \[mkIn, _] -> do
| ^^^^^^^^^^^^^^^^...