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

third_party/bazel/rules_haskell/tutorial/main/BUILD.bazel

@@ -0,0 +1,17 @@
+load(
+    "@io_tweag_rules_haskell//haskell:haskell.bzl",
+    "haskell_test",
+    "haskell_toolchain_library",
+)
+
+haskell_toolchain_library(name = "base")
+
+haskell_test(
+    name = "demorgan",
+    srcs = ["Main.hs"],
+    compiler_flags = ["-threaded"],
+    deps = [
+        ":base",
+        "//lib:booleans",
+    ],
+)

third_party/bazel/rules_haskell/tutorial/main/Main.hs

@@ -0,0 +1,16 @@
+{-# LANGUAGE StandaloneDeriving #-}
+
+module Main where
+
+import Bool
+import qualified Prelude
+import Prelude ((++), (==), ($))
+
+deriving instance Prelude.Eq Bool
+
+bools :: [Bool]
+bools = [False, True]
+
+main =
+    Prelude.print $ Prelude.and $
+      [ not (x `and` y) == not x `or` not y | x <- bools, y <- bools]