In function arguments there must not be arguments with default values before non-default ones. Modifies the signature of functions; therefore risky when using systems (such as some Symfony components) ...

Add void return type to functions with missing or empty return statements, but priority is given to @return annotations. Requires PHP >= 7.1.

Composite functions are made when the output from one function is used as the input of another function. The names of the functions are written next to each other, with the function that is used first ...