spectral/treejoin throws irrefutable pattern failed exception

[rahulmutt]

	Suppressed: eta.runtime.exception.EtaException: spectral/treejoin/Main.hs:115:7-35: Irrefutable pattern failed for pattern (f1 : ~(f2 : _))

		at base.ghc.TopHandler.runMainIO2(TopHandler.hs)
		at base.ghc.TopHandler$runMainIO2.apply1V(TopHandler.hs)
		at eta.runtime.exception.Exception.catch_(Exception.java:166)
		at main.Main.main4(Main.hs)
		at main.Main.DZCmain(Main.hs:114)
		at main.Main$DZCmain.applyV(Main.hs:114)
		at eta.runtime.stg.Closures$EvalLazyIO.enter(Closures.java:104)
		at eta.runtime.stg.Capability.schedule(Capability.java:174)
		at eta.runtime.stg.Capability.scheduleClosure(Capability.java:119)
		at eta.runtime.Runtime.evalLazyIO(Runtime.java:170)
		at eta.runtime.Runtime.main(Runtime.java:163)
		at eta.main.main(Unknown Source)
		at com.typelead.EtaBenchmark.benchmark(EtaBenchmark.java:45)
		at com.typelead.generated.EtaBenchmark_benchmark_jmhTest.benchmark_ss_jmhStub(EtaBenchmark_benchmark_jmhTest.java:780)
		at com.typelead.generated.EtaBenchmark_benchmark_jmhTest.benchmark_SingleShotTime(EtaBenchmark_benchmark_jmhTest.java:716)
		at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
		at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
		at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
		at java.lang.reflect.Method.invoke(Method.java:498)
		at org.openjdk.jmh.runner.BenchmarkHandler$BenchmarkTask.call(BenchmarkHandler.java:453)
		at org.openjdk.jmh.runner.BenchmarkHandler$BenchmarkTask.call(BenchmarkHandler.java:437)
		at java.util.concurrent.FutureTask.run(FutureTask.java:266)
		at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
		at java.util.concurrent.FutureTask.run(FutureTask.java:266)
		at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
		at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
		at java.lang.Thread.run(Thread.java:745)
	Caused by: eta.runtime.exception.EtaException: spectral/treejoin/Main.hs:115:7-35: Irrefutable pattern failed for pattern (f1 : ~(f2 : _))

		at base.ghc.io.handle.FD$sat_sIOYF.apply1V(FD.hs)
		at eta.runtime.exception.Exception.catch_(Exception.java:166)
		at base.ghc.io.handle.FD.openFile1(FD.hs:274)
		at main.Main.main1(Main.hs)
		at main.Main$main1.applyV(Main.hs)
		at eta.runtime.exception.Exception.catch_(Exception.java:129)
		... 24 more
	Caused by: eta.runtime.exception.EtaException: spectral/treejoin/Main.hs:115:7-35: Irrefutable pattern failed for pattern (f1 : ~(f2 : _))

		at base.ghc.Exception.$Lr8LTPlvl(Exception.hs)
		at base.ghc.Exception.throw1(Exception.hs)
		at base.control.exception.Base.irrefutPatError(Base.hs:396)
		at main.Main$main3.thunkEnter(Main.hs)
		at eta.runtime.thunk.CAF.evaluate(CAF.java:35)
		at main.Main$ds2_sEU0.thunkEnter(Main.hs)
		at eta.runtime.thunk.UpdatableThunk.evaluate(UpdatableThunk.java:24)
		at eta.runtime.thunk.SelectorUpd.thunkEnter(SelectorUpd.java:19)
		at eta.runtime.thunk.UpdatableThunk.evaluate(UpdatableThunk.java:24)
		at base.java.StringBase.$wgo(StringBase.hs:70)
		at base.java.StringBase.$wtoJString(StringBase.hs:69)
		at base.ghc.io.FD.openFile1(FD.hs:172)
		at base.ghc.io.handle.FD.openBinaryFile3(FD.hs:178)
		at base.ghc.io.handle.FD$sat_sIOXL.applyV(FD.hs:145)
		at eta.runtime.exception.Exception.catch_(Exception.java:129)

[rolandtritsch]

This was fixed with #12.