Add dangling changes from branches ghc-8.6 and ghc-8.8 (#1243)

* Fix multiple typos and inconsistencies in doc/markup.rst

Note: I noticed some overlap with #1112 from @wygulmage and #1081 from
@parsonsmatt after creating these proposed changes - mea culpa for not
looking at the open PRs sooner.

* Fix #1113 If no Signatures, no section of index.html

* Change the formatting of missing link destinations

The current formatting of the missing link destination does not really
help user to understand the reasons of the missing link.

To address this, I've changed the formatting in two ways:

- the missing link symbol name is now fully qualified. This way you
immediately know which haskell module cannot be linked. It is then easier
to understand why this module does not have documentation (hidden module
or broken documentation).
- one line per missing link, that's more readable now that symbol name
can be longer due to qualification.

For example, before haddock was listing missing symbol such as:

```
could not find link destinations for:
  Word8 Word16 mapMaybe
```

Now it is listed as:

```
could not find link destinations for:
  - Data.Word.Word8
  - Data.Word.Word16
  - Data.Maybe.mapMaybe
```

* Add `--ignore-link-symbol` command line argument

This argument can be used multiples time. A missing link to a symbol
listed by `--ignore-link-symbol` won't trigger "missing link" warning.

* Forbid spaces in anchors (#1148)

* Improve error messages with context information (#1060)

Co-authored-by: Matt Audesse <matt@mattaudesse.com>
Co-authored-by: Mike Pilgrem <mpilgrem@users.noreply.github.com>
Co-authored-by: Guillaume Bouchard <guillaume.bouchard@tweag.io>
Co-authored-by: Pepe Iborra <pepeiborra@gmail.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/haddock-api/src/Haddock/Interface/Rename.hs b/haddock-api/src/Haddock/Interface/Rename.hs
index 97f128d7..b4ff31e5 100644
--- a/haddock-api/src/Haddock/Interface/Rename.hs
+++ b/haddock-api/src/Haddock/Interface/Rename.hs
@@ -29,6 +29,7 @@ import Control.Applicative
 import Control.Arrow ( first )
 import Control.Monad hiding (mapM)
 import qualified Data.Map as Map hiding ( Map )
+import qualified Data.Set as Set
 import Prelude hiding (mapM)
 
 -- | Traverse docstrings and ASTs in the Haddock interface, renaming 'Name' to
@@ -39,8 +40,8 @@ import Prelude hiding (mapM)
 --
 -- The renamed output gets written into fields in the Haddock interface record
 -- that were previously left empty.
-renameInterface :: DynFlags -> LinkEnv -> Bool -> Interface -> ErrMsgM Interface
-renameInterface dflags renamingEnv warnings iface =
+renameInterface :: DynFlags -> [String] -> LinkEnv -> Bool -> Interface -> ErrMsgM Interface
+renameInterface _dflags ignoredSymbols renamingEnv warnings iface =
 
   -- first create the local env, where every name exported by this module
   -- is mapped to itself, and everything else comes from the global renaming
@@ -75,8 +76,15 @@ renameInterface dflags renamingEnv warnings iface =
       -- Note that since the renamed AST represents equality constraints as
       -- @HasOpTy t1 eqTyCon_RDR t2@ (and _not_ as @HsEqTy t1 t2@), we need to
       -- manually filter out 'eqTyCon_RDR' (aka @~@).
-      strings = [ pretty dflags n
+
+      qualifiedName n = (moduleNameString $ moduleName $ nameModule n) <> "." <> getOccString n
+
+      ignoreSet = Set.fromList ignoredSymbols
+
+      strings = [ qualifiedName n
+
                 | n <- missingNames
+                , not (qualifiedName n `Set.member` ignoreSet)
                 , not (isSystemName n)
                 , not (isBuiltInSyntax n)
                 , Exact n /= eqTyCon_RDR
@@ -88,7 +96,7 @@ renameInterface dflags renamingEnv warnings iface =
     unless (OptHide `elem` ifaceOptions iface || null strings || not warnings) $
       tell ["Warning: " ++ moduleString (ifaceMod iface) ++
             ": could not find link destinations for:\n"++
-            unwords ("   " : strings) ]
+            intercalate "\n\t- "  ("" : strings) ]
 
     return $ iface { ifaceRnDoc         = finalModuleDoc,
                      ifaceRnDocMap      = rnDocMap,