Fix code to deal with AST with irregular format in EarkMarkParser

lib/ex_doc/autolink.ex

@@ -65,6 +65,11 @@ defmodule ExDoc.Autolink do
     ast
   end
 
+  # TODO: remove this when this AST format is deprecate in EarkMarkParser
+  defp walk({:pre, _metadata, _} = ast, _config) do
+    ast
+  end
+
   defp walk({:a, metadata, attrs, inner} = ast, config) do
     cond do
       url = custom_link(attrs, config) ->

lib/ex_doc/markdown/ast.ex

@@ -74,6 +74,15 @@ defmodule ExDoc.Markdown.AST do
     ]
   end
 
+  # TODO: remove this when this AST format is deprecate in EarkMarkParser
+  defp to_html({:pre, attributes, text}, _options, _verbatim) when is_binary(text) do
+    [
+      open_element(:pre, attributes),
+      to_html([text]),
+      "</pre>\n"
+    ]
+  end
+
   # Element with no children
   defp to_html({tag, _metadata, attributes, []}, _options, _verbatim) do
     [open_element(tag, attributes), "</#{tag}>", "\n"]

lib/ex_doc/markdown/earmark.ex

@@ -102,7 +102,7 @@ defmodule ExDoc.Markdown.Earmark do
     fixup({tag, attrs, ast, %{}}, options, meta)
   end
 
-  defp fixup({:comment, children}, _options, meta) do
+  defp fixup({:comment, _, children, %{comment: true}}, _options, meta) do
     {nil, Map.put(meta, :comment, true), [], children}
   end