gnu: ghc-haddock: Update to 2.22.0.

* gnu/packages/haskell-xyz.scm (ghc-haddock): Update to 2.22.0.
[arguments]: Replace the 'remove-haddock-test-test-suites' phase with a
'remove-hoogle-test' phase, which only disables the Hoogle test; add a
new phase that puts the newly built 'haddock' binary in the 'PATH'
variable for testing.
[native-inputs]: Add 'ghc-haddock-test'.
(ghc-haddock-test): New variable.

gnu/packages/haskell-xyz.scm

@@ -4689,7 +4689,7 @@ Tor project}.")
 (define-public ghc-haddock
   (package
     (name "ghc-haddock")
-    (version "2.19.0.1")
+    (version "2.22.0")
     (source
      (origin
        (method url-fetch)
@@ -4699,16 +4699,15 @@ Tor project}.")
              ".tar.gz"))
        (sha256
         (base32
-         "1g1j9j0hf2yhyyh0gwz6bzbvfvliqz9x8a8hnkmwghm7w3xa6sb7"))))
+         "1k42z2zh550rl93c8pa9cg2xsanp6wvb031xvan6cmngnplmdib6"))))
     (build-system haskell-build-system)
     (arguments
      `(#:phases
        (modify-phases %standard-phases
-         ;; There are four test suites that require the ghc-haddock-test
+         ;; The release tarball for 2.22.0 is missing the test data for
-         ;; package, which no longer builds with GHC 8.4.3.  This phase
+         ;; the Hoogle test, causing it to fail.  This is fixed in the
-         ;; removes these four test suites from the Cabal file, so that we
+         ;; next release, but for now we disable it.
-         ;; do not need ghc-haddock-test as an input.
+         (add-before 'configure 'remove-hoogle-test
-         (add-before 'configure 'remove-haddock-test-test-suites
            (lambda _
              (use-modules (ice-9 rdelim))
              (with-atomic-file-replacement "haddock.cabal"
@@ -4719,17 +4718,20 @@ Tor project}.")
                     ((string-every char-set:whitespace line)
                      (unless deleting? (display line out))
                      (loop (read-line in 'concat) #f))
-                    ((member line '("test-suite html-test\n"
+                    ((string=? line "test-suite hoogle-test\n")
-                                    "test-suite hypsrc-test\n"
-                                    "test-suite latex-test\n"
-                                    "test-suite hoogle-test\n"))
                      (loop (read-line in 'concat) #t))
                     (else
                      (unless deleting? (display line out))
-                     (loop (read-line in 'concat) deleting?)))))))))))
+                     (loop (read-line in 'concat) deleting?))))))))
+         (add-before 'check 'add-haddock-to-path
+           (lambda _
+             (setenv "PATH" (string-append (getcwd) "/dist/build/haddock"
+                                           ":" (getenv "PATH")))
+             #t)))))
     (inputs `(("ghc-haddock-api" ,ghc-haddock-api)))
     (native-inputs
-     `(("ghc-hspec" ,ghc-hspec)))
+     `(("ghc-haddock-test" ,ghc-haddock-test)
+       ("ghc-hspec" ,ghc-hspec)))
     (home-page "https://www.haskell.org/haddock/")
     (synopsis
      "Documentation-generation tool for Haskell libraries")
@@ -4819,6 +4821,39 @@ project if you can't release often.  For interacting with Haddock itself, see
 the ‘haddock’ package.")
     (license license:bsd-3)))
 
+;; This package is needed for testing 'ghc-haddock'.  It is no longer
+;; published to Hackage, but it is maintained in the Haddock Git
+;; repository.
+(define ghc-haddock-test
+  (package
+    (name "ghc-haddock-test")
+    (version "2.22.0")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://github.com/haskell/haddock.git")
+             (commit (string-append "haddock-" version "-release"))))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32
+         "1ywxmqqan10gs0ppybdmdgsmvkzkpw7yirj2rw4qylg3x49a9zca"))))
+    (build-system haskell-build-system)
+    (arguments
+     `(#:phases
+       (modify-phases %standard-phases
+         (add-after 'unpack 'change-directory
+           (lambda _
+             (chdir "haddock-test"))))))
+    (inputs
+     `(("ghc-syb" ,ghc-syb)
+       ("ghc-xml" ,ghc-xml)))
+    (home-page "http://www.haskell.org/haddock/")
+    (synopsis "Test utilities for Haddock")
+    (description "This package provides test utilities for Haddock.")
+    (license license:bsd-3)
+    (properties '((hidden? #t)))))
+
 (define-public ghc-half
   (package
     (name "ghc-half")