Haddock needs to pass visible modules for instance filtering

The GHC-side `getNameToInstancesIndex` filters out incorrectly some
instances because it is not aware of what modules are visible. Using
`runTcInteractive` means that `ie_visible` gets initialized to a one
module set containing some dummy GHCi module. This is clearly not the
module set we want to check against to see if a given orphan instance
is visible or not.

In fact, GHC has no way of knowing what we want that module set to be
since it doesn't know ahead of time which modules Haddock is making its
docs for. The fix is just to pass that set in as an argument.

Bumps haddock submodule.

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: duog, alexbiehl, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4290

2 files changed, 7 insertions, 4 deletions

diff --git a/compiler/main/GHC.hs b/compiler/main/GHC.hs
index 343ef37210..1e54f0efac 100644
--- a/compiler/main/GHC.hs
+++ b/compiler/main/GHC.hs
@@ -1244,12 +1244,15 @@ getGRE = withSession $ \hsc_env-> return $ ic_rn_gbl_env (hsc_IC hsc_env)
 -- by 'Name'. Each name's lists will contain every instance in which that name
 -- is mentioned in the instance head.
 getNameToInstancesIndex :: GhcMonad m
-  => m (Messages, Maybe (NameEnv ([ClsInst], [FamInst])))
-getNameToInstancesIndex = do
+  => [Module]  -- ^ visible modules. An orphan instance will be returned if and
+               -- only it is visible from at least one module in the list.
+  -> m (Messages, Maybe (NameEnv ([ClsInst], [FamInst])))
+getNameToInstancesIndex visible_mods = do
   hsc_env <- getSession
   liftIO $ runTcInteractive hsc_env $
     do { loadUnqualIfaces hsc_env (hsc_IC hsc_env)
-       ; InstEnvs {ie_global, ie_local, ie_visible} <- tcGetInstEnvs
+       ; InstEnvs {ie_global, ie_local} <- tcGetInstEnvs
+       ; let visible_mods' = mkModuleSet visible_mods
        ; (pkg_fie, home_fie) <- tcGetFamInstEnvs
        -- We use Data.Sequence.Seq because we are creating left associated
        -- mappends.
@@ -1257,7 +1260,7 @@ getNameToInstancesIndex = do
        ; let cls_index = Map.fromListWith mappend
                  [ (n, Seq.singleton ispec)
                  | ispec <- instEnvElts ie_local ++ instEnvElts ie_global
-                 , instIsVisible ie_visible ispec
+                 , instIsVisible visible_mods' ispec
                  , n <- nameSetElemsStable $ orphNamesOfClsInst ispec
                  ]
        ; let fam_index = Map.fromListWith mappend
diff --git a/utils/haddock b/utils/haddock
-Subproject 24841386cff6fdccc11accf9daa815c2c7444d6
+Subproject dd80ae1773ea6aae48c3c5a899d510699783d6e