declaring the type of a class property makes sense imo, even if the id
could guess it from the initialization. it makes the code more
understandable to me. but indeed for property doc it should be
multiline. in the concrete case i propose to replace that with typehints
for the class/interface these mocks stand for. typehinting the mock
class has not much value.

btw we also have inline comments in the middle of methods in some
places. of course if the method can typehint the argument, that is what
it should do, and when the method call it gets an object with can
specify the return type, no additional comment should be used. but they
make sense for cases of mixed parameters or i.e. in doctrine when you
have to implement the method typehint with something from core, but you
know you actually get the phpcr-odm extension of that class. or for
iterators where the idea has no clue what objects could be in the iterator.