Markdown reader: don't increment stateNoteNumber for example refs.

Background:  syntactically, references to example list items
can't be distinguished from citations; we only know which they
are after we've parsed the whole document (and this is resolved
in the `runF` stage).

This means that pandoc's calculation of `citationNoteNum`
can sometimes be wrong when there are example list references.

This commit partially addresses #6836, but only for the case
where the example list references refer to list items defined
previously in the document.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/Text/Pandoc/Readers/Markdown.hs b/src/Text/Pandoc/Readers/Markdown.hs
index 64a2db288..e62a8a978 100644
--- a/src/Text/Pandoc/Readers/Markdown.hs
+++ b/src/Text/Pandoc/Readers/Markdown.hs
@@ -1535,6 +1535,11 @@ ltSign = do
   char '<'
   return $ return $ B.str "<"
 
+-- Note that if the citations extension is enabled, example refs will be
+-- parsed as citations, and handled by a clause in the parser for citations,
+-- since we won't know whether we have an example ref until the
+-- whole document has been parsed.  But we need this parser
+-- here in case citations is disabled.
 exampleRef :: PandocMonad m => MarkdownParser m (F Inlines)
 exampleRef = try $ do
   guardEnabled Ext_example_lists
@@ -2066,6 +2071,13 @@ cite = do
 textualCite :: PandocMonad m => MarkdownParser m (F Inlines)
 textualCite = try $ do
   (suppressAuthor, key) <- citeKey
+  -- If this is a reference to an earlier example list item,
+  -- then don't parse it as a citation.  If the example list
+  -- item comes later, we'll parse it here and figure out in
+  -- the runF stage if it's a citation.  But it helps with
+  -- issue #6836 to filter out known example list references
+  -- at this stage, so we don't increment stateNoteNumber.
+  getState >>= guard . isNothing . M.lookup key . stateExamples
   noteNum <- stateNoteNumber <$> getState
   let first = Citation{ citationId      = key
                       , citationPrefix  = []