[clean-list] Funny identifiers starting with double colon

[Vag Vagoff]

Hi!

Compiler eats

:: A = ::: | .:: | ?:: | ::? | :::!!! |  | :::.

but complains on each

:: A = ::!
:: A = !::
:: A = ::.

i.e. every identifier starting with ! or with :: (excluding :::) considered incorrect.

Is this intended behavior?

Thanks in advance,
Vag.