Component/s: Coding style
Type hints and return type declarations are available in all supported versions of PHP and we typically use them.
This issue is about formalising the requirement of their use in all possible locations for all new code.
To be clear, there will be necessary exclusions:
- code extending existing non-compliant code and implementing things where it is not available
- ... Hmm... maybe others too?
- Require them for the new methods (except for the previous exclusions).
- Leave things as they are: use type hints and return type declarations is recommended, but still optional.