HRTB plus an additional bound in container whithout dyn

[leudz]

Having something like:

type Alias = Box<for<'a> Test<'a> + Send>;

triggers some syntax errors:

• expected COMMA and expected R_ANGLE right after Test<'a>
• expected SEMI and expected an item at the last angle bracket
• expected an item at the semi-colon

It works perfectly fine if I add the dyn that should have been there from the beginning.
I tried a few things and only the first two errors seem to be related to this issue, the others being a result of them.

Here's a playground.

[bjorn3]

triage: still an issue