From the Treehouse blog:
With PHP 7 we now have added Scalar types. Specifically: int, float, string, and bool.
By adding scalar type hints and enabling strict requirements, it is hoped that more correct and self-documenting PHP programs can be written. It also gives you more control over your code and can make the code easier to read.
By default, scalar type-declarations are non-strict, which means they will attempt to change the original type to match the type specified by the type-declaration. In other words, if you pass a string that starts with a number into a function that requires a float, it will grab the number from the beginning and remove everything else. Passing a float into a function that requires an int will become int[1].
By default, PHP will cast values of the wrong type into the expected scalar type if possible. For example, a function that is given an integer for a parameter that expects a string will get a variable of type string.
Strict types disabled [eval]: