[PR][php-langspec][#177] - A `list` cannot be empty

You can view the Pull Request on github:
https://github.com/php/php-langspec/pull/177

Comment by nikic:
The important part here is the sentence "At least one of the elements of the *list-expression-list* must be non-empty" in the constraint section. What this means is that not only `list()`, but also `list(,)` or `list(,,,,,)` are forbidden. (Zend allows an empty `list()` syntactically, but does rejects it lateron.)