Broken documentation links

[gdeest]

It looks like documentation links between Bazel packages are broken. I can reproduce the issue with the following setup:

./WORKSPACE:

workspace(name = "bugrepro")

rules_haskell_rev="fa789428cbc95746effc793c353cb46507580729"
http_archive(
    name = "io_tweag_rules_haskell",
    strip_prefix = "rules_haskell-{}".format(rules_haskell_rev),
    urls = ["https://github.com/tweag/rules_haskell/archive/{}.tar.gz".format(rules_haskell_rev)],
)

load("@io_tweag_rules_haskell//haskell:repositories.bzl", "haskell_repositories")
haskell_repositories()

http_archive(
  name = "io_tweag_rules_nixpkgs",
  strip_prefix = "rules_nixpkgs-0.2",
  urls = ["https://github.com/tweag/rules_nixpkgs/archive/v0.2.tar.gz"],
)

load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl", "nixpkgs_package")

nixpkgs_package(
  name = "ghc",
  attribute_path = "haskell.compiler.ghc822",
)

register_toolchains("//:ghc")

./BUILD:

package(default_visibility = ["//visibility:public"])

load(
  "@io_tweag_rules_haskell//haskell:haskell.bzl",
  "haskell_doc",
  "haskell_toolchain",
)

haskell_toolchain(
  name = "ghc",
  version = "8.2.2",
  tools = "@ghc//:bin",
)

haskell_doc(
  name = "my-doc",
  deps = ["//libB"],
)

./libA/BUILD:

package(default_visibility = ["//visibility:public"])

load(
  "@io_tweag_rules_haskell//haskell:haskell.bzl",
  "haskell_library",
  "haskell_toolchain",
)

haskell_toolchain(
  name = "ghc",
  version = "8.2.2",
  tools = "@ghc//:bin",
)

haskell_library(
  name = "libA",
  srcs = ['LibA.hs'],
  prebuilt_dependencies = ["base"],
)

./libA/LibA.hs:

module LibA where

newtype MyFoo = MyFoo String

./libB/BUILD:

package(default_visibility = ["//visibility:public"])

load(
  "@io_tweag_rules_haskell//haskell:haskell.bzl",
  "haskell_library",
  "haskell_toolchain",
)

haskell_toolchain(
  name = "ghc",
  version = "8.2.2",
  tools = "@ghc//:bin",
)

haskell_library(
  name = "libB",
  srcs = glob(['LibB.hs']),
  prebuilt_dependencies = ["base"],
  deps = ["//libA"]
)

./libB/LibB.hs:

module LibB where

import LibA

foo :: MyFoo
foo = MyFoo "foo"

When running bazel build //..., documentation for libB is properly generated and can be opened in a web browser. However, the link to the MyFoo type is broken.