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

third_party/bazel/rules_haskell/tests/haskell_toolchain_library/BUILD.bazel

@@ -0,0 +1,26 @@
+load(
+    "@io_tweag_rules_haskell//haskell:haskell.bzl",
+    "haskell_library",
+    "haskell_test",
+)
+
+package(default_testonly = 1)
+
+haskell_library(
+    name = "Lib",
+    srcs = ["Lib.hs"],
+    deps = [
+        "//tests/hackage:base",
+        "//tests/hackage:bytestring",
+    ],
+)
+
+haskell_test(
+    name = "binary",
+    srcs = ["Bin.hs"],
+    deps = [
+        ":Lib",
+        "//tests/hackage:base",
+        "//tests/hackage:text",
+    ],
+)

third_party/bazel/rules_haskell/tests/haskell_toolchain_library/Bin.hs

@@ -0,0 +1,8 @@
+module Main (main) where
+
+import qualified Data.Text.IO as T
+import qualified Data.Text.Encoding as E
+
+import Lib (message)
+
+main = T.putStrLn $ E.decodeUtf8 message

third_party/bazel/rules_haskell/tests/haskell_toolchain_library/Lib.hs

@@ -0,0 +1,5 @@
+module Lib (message) where
+
+import qualified Data.ByteString.Char8 as B
+
+message = B.pack "hello, world"