Argument X passed to Y must be an instance of boolean, boolean given - PHP7

问题

Given code

<?php
function a(boolean $value){
    var_dump($value);
}
a(true);

I receive error

TypeError: Argument 1 passed to a() must be an instance of boolean, boolean given

What is going on here?

回答1:

Only valid typehint for boolean is bool. As per documentation boolean isn't recognized as alias of bool in typehints. Instead it is treated as class name. Same goes for int(scalar) and integer(class name), which will result in error

TypeError: Argument 1 passed to a() must be an instance of integer, integer given

In this specific case object of class boolean is expected but true(bool, scalar) is passed.

Valid code is

<?php
function a(bool $value){
    var_dump($value);
}
a(true);

which result is

bool(true)

来源：https://stackoverflow.com/questions/45348751/argument-x-passed-to-y-must-be-an-instance-of-boolean-boolean-given-php7