-dphPackage dflags = case dphBackend dflags of
- DPHPar -> dphParPackageId
- DPHSeq -> dphSeqPackageId
- DPHThis -> thisPackage dflags
+dphPackage dflags
+ = case dphBackend dflags of
+ DPHPar -> dphParPackageId
+ DPHSeq -> dphSeqPackageId
+ DPHThis -> thisPackage dflags
+ DPHNone -> ghcError (CmdLineError dphBackendError)
+
+dphBackendError :: String
+dphBackendError = "To use -fvectorise select a DPH backend with -fdph-par or -fdph-seq"