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

third_party/bazel/rules_haskell/tests/lhs/BUILD.bazel

@@ -0,0 +1,23 @@
+load(
+    "@io_tweag_rules_haskell//haskell:haskell.bzl",
+    "haskell_library",
+    "haskell_test",
+)
+
+package(default_testonly = 1)
+
+haskell_library(
+    name = "lhs-lib",
+    srcs = ["Lib.lhs"],
+    deps = ["//tests/hackage:base"],
+)
+
+haskell_test(
+    name = "lhs-bin",
+    srcs = ["Main.lhs"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":lhs-lib",
+        "//tests/hackage:base",
+    ],
+)

third_party/bazel/rules_haskell/tests/lhs/Lib.lhs

@@ -0,0 +1,4 @@
+> module Lib (lib) where
+
+> lib :: String
+> lib = "lhs"

third_party/bazel/rules_haskell/tests/lhs/Main.lhs

@@ -0,0 +1,6 @@
+> module Main (main) where
+
+> import Lib (lib)
+
+> main :: IO ()
+> main = putStrLn lib