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)