Jani Hartikainen has a new post with a gotcha he came across when using typehinting in exceptions and methods.
A small gotcha I recently ran into: If you use typehinting, PHP never checks that the class your typehint specifies actually exists!
He includes simple examples that define the class type hint as some random string and PHP never throws an error for it. He also notes that it's even worse when dealing with namespaces - how it handles exceptions locally unless you specify otherwise. Of course, these "features" can be put to good use in the right situations, but they can be confusing for a developer without a keen eye.