Regex for this explicit ask for start of string or newline:

$text = preg_replace( '/(^|\n)-----*/', '\\1<hr />', $text );

in Parser.php::internalParse()

Looks like works as expected

(In reply to comment #1)

Regex for this explicit ask for start of string or newline:

$text = preg_replace( '/(^|\n)-----*/', '\\1<hr />', $text );

in Parser.php::internalParse()

Looks like works as expected

I've made an example, see https://en.wikipedia.org/w/index.php?title=User:Rezonansowy/sandbox&oldid=592775616

I believe it is working as expected, and I don't see why we should change that. Otherwise, it could break existing pages.

(In reply to Ricordisamoa from comment #3)

I believe it is working as expected, and I don't see why we should change
that. Otherwise, it could break existing pages.

No it doesn't, it's a layout bug. Risk that it could break existing pages is very low, nobody codes using layout bugs as a target, besides for similar appearance we have the <nowiki /> tag.
Regards

This is a bug in MediaWiki parser, which prevents to comment with lines on page talks for example. Normal priority would be OK here.