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, 8 insertions, 2 deletions

diff --git a/haddock-api/src/Haddock/Options.hs b/haddock-api/src/Haddock/Options.hs
index 510810b0..8a18a60d 100644
--- a/haddock-api/src/Haddock/Options.hs
+++ b/haddock-api/src/Haddock/Options.hs
@@ -36,7 +36,8 @@ module Haddock.Options (
   readIfaceArgs,
   optPackageName,
   optPackageVersion,
-  modulePackageInfo
+  modulePackageInfo,
+  ignoredSymbols
 ) where
 
 
@@ -108,6 +109,7 @@ data Flag
   | Flag_PackageVersion String
   | Flag_Reexport String
   | Flag_SinceQualification String
+  | Flag_IgnoreLinkSymbol String
   deriving (Eq, Show)
 
 
@@ -219,7 +221,9 @@ options backwardsCompat =
     Option [] ["package-version"] (ReqArg Flag_PackageVersion "VERSION")
       "version of the package being documented in usual x.y.z.w format",
     Option []  ["since-qual"] (ReqArg Flag_SinceQualification "QUAL")
-      "package qualification of @since, one of\n'always' (default) or 'only-external'"
+      "package qualification of @since, one of\n'always' (default) or 'only-external'",
+    Option [] ["ignore-link-symbol"] (ReqArg Flag_IgnoreLinkSymbol "SYMBOL")
+      "name of a symbol which does not trigger a warning in case of link issue"
   ]
 
 
@@ -336,6 +340,8 @@ verbosity flags =
       Left e -> throwE e
       Right v -> v
 
+ignoredSymbols :: [Flag] -> [String]
+ignoredSymbols flags = [ symbol | Flag_IgnoreLinkSymbol symbol <- flags ]
 
 ghcFlags :: [Flag] -> [String]
 ghcFlags flags = [ option | Flag_OptGhc option <- flags ]