- Remove AST_LIST and mark it as deprecated, and remove it whenever AST version 50 is removed.
Related to #94 - It was overlooked
AST_LIST is still used in https://github.com/phan/phan/blob/1.2.2/src/Phan/Analysis/PreOrderAnalysisVisitor.php#L613 (incorrectly, will fix)
- Change the reflection arginfo of ast\parse_code and ast\parse_file to make the int $version mandatory
Remove legacy flags such as ast\flags\RETURNS_REF (alias of ast\flags\FUNC_RETURNS_REF mentioned in README)