User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:66.0) Gecko/20100101 Firefox/66.0

Steps to reproduce:

Upgraded Firefox to version 66, then typed ‘#pop’ in the URL bar to go to a bookmarked page, for which I have ‘#pop’ set as its keyword search.

Actual results:

I got the error page “Hmm. That address doesn’t look right.” as would be expected if that term wasn't a bookmark keyword. (I have the ‘automatically turn errors into web searches’ thingy disabled.)

Expected results:

It should have navigated to the URL associated with that keyword, as it did in Firefox 65.

Trying assorted other punctuation characters, these all work as expected: ‘!pop’, ‘!$pop’, ‘%pop’, and ‘/pop’ — I couldn't find anything else that fails, other than a leading hash symbol.

Putting a hash in the middle of the keyword, as in ‘p#op’, also works fine; it's only a hash as the first character which fails to match.

The bookmark is for a search for a Twitter hashtag (#PopMaster), so starting the keyword with a hash is a useful mnemonic. It's actually what I was already typing to find that page before creating the bookmark, matching against titles of recently visited pages. But sometimes that would give me a slightly different page, so it was worth creating a bookmark, and handy to set the keyword to what I was already typing.

I wasn't sure whether a keyword starting with a punctuation character would work (and if it hadn't worked when I set it up, I wouldn't've complained), but given I had a working keyword, it's a shame for it to stop working on Firefox upgrade.

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=d11bb3bd81951e0e5a66bc9e3ae80ca22d2ad13f&tochange=f2f4a6eb1576cba580ee99971f5fc035cbaeeab1

Regreseed by: f2f4a6eb1576 Marco Bonardo — Bug 1514780 - Use the Quantum Bar tokenizer in UnifiedComplete. r=adw

Yes, keywords starting with a restriction character don't work anymore, adding back thieir support is tricky at the moment, I explain it better at https://bugzilla.mozilla.org/show_bug.cgi?id=1538050#c4 and at https://bugzilla.mozilla.org/show_bug.cgi?id=1517140#c9.

I'm duping to bug 1517140 because for now that's the expected path forward, that means we may not add back that support. An anyway we can't add back that support until we are done refactoring the code.