diff options
| -rw-r--r-- | compiler/main/Packages.lhs | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/compiler/main/Packages.lhs b/compiler/main/Packages.lhs index b080b95b1a..ff316aa021 100644 --- a/compiler/main/Packages.lhs +++ b/compiler/main/Packages.lhs @@ -359,6 +359,15 @@ comparing f a b = f a `compare` f b packageFlagErr :: PackageFlag -> [(PackageConfig, UnusablePackageReason)] -> IO a + +-- for missing DPH package we emit a more helpful error message, because +-- this may be the result of using -fdph-par or -fdph-seq. +packageFlagErr (ExposePackage pkg) [] | is_dph_package pkg + = ghcError (CmdLineError (showSDoc $ dph_err)) + where dph_err = text "the " <> text pkg <> text " package is not installed." + $$ text "To install it: \"cabal install dph\"." + is_dph_package pkg = "dph" `isPrefixOf` pkg + packageFlagErr flag reasons = ghcError (CmdLineError (showSDoc $ err)) where err = text "cannot satisfy " <> ppr_flag <> (if null reasons then empty else text ": ") $$ |