[css-values-5] <any-value> in functional <general-enclosed> should be a non-strict comma-containing production #11042
Description
About comma-containing productions in functional notations:
If it does not start with a "{" token, then it cannot contain commas or {} blocks
There is an exception for var(..., <declaration-value>) by defining <declaration-value> as a non-strict comma-containing production, but not for <functional-token> <any-value> ):
For example, this is valid today but not when applying the new rules for comma-containing productions:
@media unknown(foo, bar) {}@media unknown({ foo }, bar) {}:is(foo, bar):is({ foo }, bar)
Note: :is() is consumed as a function but it may be considered as a selector instead (as in Bikeshed).
Even if they were defined as non-strict, { foo }, bar would be invalid:
[A non-strict comma-containing production] still follows the standard comma-containing production rules when it does start with a "{" token [...]
These standard comma-containing production rules prevent matching further than { foo }:
If it does start with a "{" token, then the production matches just the {} block
Breaking backward-compatibility may be ok. I dunno. Otherwise the "general functional notation" argument may need to be excluded from the comma-containing production rules.