Hello,

unless I am mistaken, the rfc you link has been passed allowing for type hints to be _widened_, that is, that declaring an untyped variable could pass a typed variable, whereas what you are doing is the inverse.

That is, if the interface was typed with int, you could implement it without the int, but not add the int where the interface declares untyped.

> unless I am mistaken, the rfc you link has been passed allowing for type hints to be _widened_, that is, that declaring an untyped variable could pass a typed variable, whereas what you are doing is the inverse.

As a picture is worth a thousand words, here is an illustration:

Current situation
-----------------

interface SeekableIterator extends Iterator {
    function seek($position);
}

class LegacyFoo implements SeekableIterator {
    // (implementation of Iterator elided)
    function seek($position) { } // ok
}

class FutureFoo implements SeekableIterator {
    // (implementation of Iterator elided)
    function seek(int $position) { } // Error
}


Proposed change
---------------

interface SeekableIterator extends Iterator {
    function seek(int $position);
}

class LegacyFoo implements SeekableIterator {
    // (implementation of Iterator elided)
    function seek($position) { } // ok (since RFC implemented)
}

class FutureFoo implements SeekableIterator {
    // (implementation of Iterator elided)
    function seek(int $position) { } // ok
}

Adding the int type *should* indeed be backwards compatible nowadays. I've added it on master (7.4) only, since I don't trust that "should" enough to change this on stable branches.