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

third_party/bazel/rules_haskell/tests/library-deps/BUILD.bazel

@@ -0,0 +1,28 @@
+load(
+    "@io_tweag_rules_haskell//haskell:haskell.bzl",
+    "haskell_library",
+    "haskell_test",
+)
+
+package(default_testonly = 1)
+
+haskell_library(
+    name = "library-deps",
+    srcs = ["TestLib.hs"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//tests/hackage:base",
+        "//tests/library-deps/sublib",
+    ],
+)
+
+haskell_test(
+    name = "bin-deps",
+    size = "small",
+    srcs = ["Bin.hs"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//tests/hackage:base",
+        "//tests/library-deps/sublib",
+    ],
+)

third_party/bazel/rules_haskell/tests/library-deps/Bin.hs

@@ -0,0 +1,6 @@
+module Main (main) where
+
+import TestSubLib (messageEnd)
+
+main :: IO ()
+main = putStrLn $ messageEnd

third_party/bazel/rules_haskell/tests/library-deps/TestLib.hs

@@ -0,0 +1,9 @@
+module TestLib (testMessage) where
+
+import TestSubLib (messageEnd)
+
+testMessage :: String
+testMessage = "hello " ++ messageEnd
+
+-- Force dynamic linking
+{-# ANN testMessage () #-}

third_party/bazel/rules_haskell/tests/library-deps/sublib/BUILD.bazel

@@ -0,0 +1,21 @@
+load(
+    "@io_tweag_rules_haskell//haskell:haskell.bzl",
+    "haskell_library",
+)
+
+package(default_testonly = 1)
+
+haskell_library(
+    name = "sublib",
+    srcs = ["TestSubLib.hs"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":sublib-c",
+        "//tests/hackage:base",
+    ],
+)
+
+cc_library(
+    name = "sublib-c",
+    srcs = ["sublib-c.c"],
+)

third_party/bazel/rules_haskell/tests/library-deps/sublib/TestSubLib.hs

@@ -0,0 +1,7 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+module TestSubLib (messageEnd) where
+
+messageEnd :: String
+messageEnd = "world " ++ show (foo 10)
+
+foreign import ccall foo :: Int -> Int

third_party/bazel/rules_haskell/tests/library-deps/sublib/sublib-c.c

@@ -0,0 +1,3 @@
+int foo(int x) {
+  return x * 2;
+}