feat(third_party/bazel): Check in rules_haskell from Tweag

third_party/bazel/rules_haskell/tests/package-name/Main.hs

@@ -0,0 +1,33 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE PackageImports #-}
+module Main (main) where
+
+import Control.Monad (when)
+
+-- Test the PackageImports extension.
+import "lib-a-Z" Lib
+
+-- Test macros that GHC creates automatically based on the package version.
+versionHighEnoughTest, versionTooLowTest :: Bool
+#if MIN_VERSION_lib_a_Z(1,2,3)
+versionHighEnoughTest = True
+#else
+versionHighEnoughTest = False
+#endif
+
+#if MIN_VERSION_lib_a_Z(1,2,4)
+versionTooLowTest = False
+#else
+versionTooLowTest = True
+#endif
+
+check :: (Show a, Eq a) => a -> a -> IO ()
+check x y = when (x /= y) $ error $ "Failed check: " ++ show (x, y)
+
+main :: IO ()
+main = do
+    check foo 42
+    check VERSION_lib_a_Z "1.2.3.4"
+    check libPackageKey "testsZSpackage-nameZSlib-a-ZZ"
+    check versionHighEnoughTest True
+    check versionTooLowTest True