Fix the bug when comments in different styles get glued together

CHANGELOG.md

@@ -1,3 +1,8 @@
+## Ormolu 0.1.2.0
+
+* Fixed the bug when comments in different styles got glued together after
+  formatting. [Issue 589](https://github.com/tweag/ormolu/issues/589).
+
 ## Ormolu 0.1.1.0
 
 * Imports in a import lists are now normalized: duplicate imports are

data/examples/other/comment-glued-together-out.hs

@@ -0,0 +1,7 @@
+module Main (main) where
+
+-- | Foo.
+
+-- Bar
+main :: IO ()
+main = return ()

data/examples/other/comment-glued-together.hs

@@ -0,0 +1,6 @@
+module Main (main) where
+
+{- | Foo. -}
+-- Bar
+main :: IO ()
+main = return ()

expected-failures/idris.txt

@@ -2,10 +2,6 @@ The GHC parser (in Haddock mode) failed:
   src/Idris/Parser.hs:1052:1
   parse error on input `@'
 
-AST of input and AST of formatted code differ.
-  at src/Idris/Parser/Data.hs:281:1-29
-Please, consider reporting the bug.
-
 The GHC parser (in Haddock mode) failed:
   src/Idris/Parser/Expr.hs:75:1
   parse error on input `@'

src/Ormolu/Printer/Comments.hs

@@ -154,6 +154,7 @@ needsNewlineBefore ::
   -- | Last printed comment span
   Maybe SpanMark ->
   Bool
+needsNewlineBefore _ (Just (HaddockSpan _ _)) = True
 needsNewlineBefore l mlastMark =
   case spanMarkSpan <$> mlastMark of
     Nothing -> False
@@ -238,8 +239,7 @@ commentFollowsElt ref mnSpn meSpn mlastMark (L l comment) =
       -- lexemes in front of it and goes right after the previous comment.
       not (hasAtomsBefore comment)
         && ( case mlastMark of
-               Just (HaddockSpan _ spn) ->
-                 srcSpanEndLine spn + 1 == srcSpanStartLine l
+               Just (HaddockSpan _ _) -> False
                Just (CommentSpan spn) ->
                  srcSpanEndLine spn + 1 == srcSpanStartLine l
                _ -> False