Stefan Monnier <monnier@iro.umontreal.ca> writes:

> I pushed a patch which should fix the "lone >" problem without
> introducing any undue extra cost.  It should also fix the "very long
> line" case.

Seems to pass my tests.  Not sure if you missed the alternate fix I
proposed in https://debbugs.gnu.org/33887#94 or not.  It does have the
disadvantage of leaving (car (syntax-ppss)) unreliable for any other
code which uses it.

Here's a patch against master that should cover the remaining cases
Vincent raised: