List of PHP behaviours you don't expect

This is a list of some unexpected behaviours when developing in PHP.

It doesn't mean they are bugs. It only means you should be aware of them.

• Numeric string comparison
• 0 to string comparison
• Change boolean constants TRUE/FALSE (Fixed in PHP-7.0)
• Overwriting $this when using references (Fixed in PHP-7.1)
• Automatic type conversion on array keys
• Late constant binding
• Reference returning
• Callable type-hint not directly callable (Fixed in PHP-7.0)
• Hidden array element (Fixed in PHP-7.2)