RST reader: fix double-link bug.

Link labels containing raw URLs were parsed as autolinks,
but links within links are not allowed.

Closes #4581.

src/Text/Pandoc/Readers/RST.hs

@@ -45,6 +45,7 @@ import Data.Maybe (fromMaybe, isJust)
 import Data.Sequence (ViewR (..), viewr)
 import Data.Text (Text)
 import qualified Data.Text as T
+import Text.Pandoc.Walk (walk)
 import Text.Pandoc.Builder (Blocks, Inlines, fromList, setMeta, trimInlines)
 import qualified Text.Pandoc.Builder as B
 import Text.Pandoc.Class (PandocMonad, fetchItem, readFileFromDirs)
@@ -1479,7 +1480,7 @@ explicitLink :: PandocMonad m => RSTParser m Inlines
 explicitLink = try $ do
   char '`'
   notFollowedBy (char '`') -- `` marks start of inline code
-  label' <- trimInlines . mconcat <$>
+  label' <- removeLinks . trimInlines . mconcat <$>
              manyTill (notFollowedBy (char '`') >> inline) (char '<')
   src <- trim <$> manyTill (noneOf ">\n") (char '>')
   skipSpaces
@@ -1494,6 +1495,12 @@ explicitLink = try $ do
                           _      -> return ((src, ""), nullAttr)
   return $ B.linkWith attr (escapeURI src') tit label''
 
+removeLinks :: B.Inlines -> B.Inlines
+removeLinks = B.fromList . walk (concatMap go) . B.toList
+  where go :: Inline -> [Inline]
+        go (Link _ lab _) = lab
+        go x              = [x]
+
 citationName :: PandocMonad m => RSTParser m String
 citationName = do
   raw <- citationMarker

test/command/4581.md

@@ -0,0 +1,6 @@
+```
+% pandoc -f rst -t native
+`http://loc <http://loc>`__
+^D
+[Para [Link ("",[],[]) [Str "http://loc"] ("http://loc","")]]
+```