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

third_party/bazel/rules_haskell/tests/haskell_lint/BUILD.bazel

@@ -0,0 +1,47 @@
+load(
+    "@io_tweag_rules_haskell//haskell:haskell.bzl",
+    "haskell_library",
+    "haskell_lint",
+    "haskell_test",
+)
+
+package(default_testonly = 1)
+
+haskell_library(
+    name = "lib-a",
+    srcs = ["Foo.hs"],
+    visibility = ["//visibility:public"],
+    deps = ["//tests/hackage:base"],
+)
+
+haskell_library(
+    name = "lib-b",
+    srcs = ["Bar.hs"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":lib-a",
+        "//tests/hackage:base",
+    ],
+)
+
+haskell_lint(
+    name = "lint-lib-b",
+    visibility = ["//visibility:public"],
+    deps = [":lib-b"],
+)
+
+haskell_test(
+    name = "bin",
+    srcs = ["Main.hs"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":lib-a",
+        "//tests/hackage:base",
+    ],
+)
+
+haskell_lint(
+    name = "lint-bin",
+    visibility = ["//visibility:public"],
+    deps = [":bin"],
+)

third_party/bazel/rules_haskell/tests/haskell_lint/Bar.hs

@@ -0,0 +1,6 @@
+module Bar (bar) where
+
+import Foo (foo)
+
+bar :: Int
+bar = 4 + foo :: Int

third_party/bazel/rules_haskell/tests/haskell_lint/Foo.hs

@@ -0,0 +1,4 @@
+module Foo (foo) where
+
+foo :: Int
+foo = 5 :: Int

third_party/bazel/rules_haskell/tests/haskell_lint/Main.hs

@@ -0,0 +1,6 @@
+module Main (main) where
+
+import Foo (foo)
+
+main :: IO ()
+main = print foo