With a slow validate build on OSX x86_64, PolyKinds10 fails:

=====> PolyKinds10(normal) 2 of 13 [0, 0, 0]
cd . && '/Users/ian/ghc/7.4-branch/val64/inplace/bin/ghc-stage2' -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-conf -rtsopts  -fno-ghci-history -o PolyKinds10 PolyKinds10.hs    >PolyKinds10.comp.stderr 2>&1
Compile failed (status 256) errors were:
[1 of 1] Compiling Main             ( PolyKinds10.hs, PolyKinds10.o )
ghc-stage2: panic! (the 'impossible' happened)
  (GHC version 7.4.0.20120126 for x86_64-apple-darwin):
        ASSERT failed! file compiler/types/Kind.lhs line 258
[ghc-prim:GHC.Prim.*{(w) tc 34d}] [ghc-prim:GHC.Prim.*{(w) tc 34d}]

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug


*** unexpected failure for PolyKinds10(normal)