"hmake -hat -package GLUT Main" fails with: "Fail: /usr/include/hat/DoublyLinked.hx: openFile: does not exist (No such file or directory)". DoublyLinked.hs is sitting right in the directory from which I'm compiling, I'm not sure why the -hat flag causes this digging in /usr/include. Deleting "-hat" causes successful compilation. The directory tree looks like this: lanes/ ByKey.hs DoublyLinked.hs IfPrime.hs Main.hs MaybeBool.hs Traffic.hs Traffic/ lanes/Traffic/ Data.hs Sim.hs Units.hs This is hat 2.02-12 and hmake-3.09-3 on Debian stable x86. This is the full text of the build: _______________________________________________________________________________ abu ~/sync/lanes hmake -hat -package GLUT Main hat-trans MaybeBool.hs Creating directories Hat Wrote Hat/MaybeBool.hs /usr/bin/haskell-compiler -package GLUT -c -package hat -o Hat/MaybeBool.o Hat/MaybeBool.hs hat-trans Traffic/Units.hs Creating directories Hat Hat/Traffic Wrote Hat/Traffic/Units.hs /usr/bin/haskell-compiler -package GLUT -c -package hat -o Hat/Traffic/Units.o Hat/Traffic/Units.hs hat-trans DoublyLinked.hs Wrote Hat/DoublyLinked.hs /usr/bin/haskell-compiler -package GLUT -c -package hat -o Hat/DoublyLinked.o Hat/DoublyLinked.hs hat-trans ByKey.hs Wrote Hat/ByKey.hs /usr/bin/haskell-compiler -package GLUT -c -package hat -o Hat/ByKey.o Hat/ByKey.hs hat-trans IfPrime.hs Wrote Hat/IfPrime.hs /usr/bin/haskell-compiler -package GLUT -c -package hat -o Hat/IfPrime.o Hat/IfPrime.hs hat-trans Traffic/Sim.hs Fail: /usr/include/hat/DoublyLinked.hx: openFile: does not exist (No such file or directory) _______________________________________________________________________________ in Traffic/Sim.hs the line including DoublyLinked looks like this: "import qualified DoublyLinked as DL"