Annotating Types via PHP Doc Comments

PHP Analyzer generally infers types just by looking at your code. Besides that many PHP projects also make use of doc comments to enhance type inference of IDEs and static analysis tools. This document explains which doc comments are being considered by PHP Analyzer.

Supported Doc Comments

PHP Analyzer currently reads the following doc comments:

  • @param [type] $[paramName] for functions/methods
  • @return [type] for functions/methods
  • @var [type] $[variableName] everywhere
  • @type [type] $[variableName] everywhere


Generally, it is not necessary to add doc comments to each and every element, PHP Analyzer is smart enough to infer most types for you. In some cases, we explicitly recommend to add doc comments though:


Since interfaces have no code from which a type can be inferred. We recommend that their methods are always annotated. For parameters, a comment is not strictly necessary if it is already covered by a type hint. Return types should always be specified via a comment, even if the method does not have a return value in which case you can use the void type. If no type is specified, we will assume unknown (a special, internal type that passes all checks).


PHP itself provides the generic array type hint. Unfortunately, that does not allow to specify what the types of its values are. Therefore, we encourage to specify a more specific type via comments using either the Type[] syntax, or the array<Type> syntax; both are equivalent.

Type Reference

This is a reference of which types are supported in doc comments.

Type Description
boolean, Boolean, or bool Value can be true, or false
false Value can be only boolean false. This only makes sense in combination with another type, e.g. false|string.
integer, or int Value is an integer.
float, or double Value is a float.
string Value is a string.
null Value is null. This only makes sense in combination with another type, e.g. string|null.
callable Value is a callable, that is a string, array, or object that implements __invoke.
void Value is of no type. This type is solely reserved for return type of methods without a body.
self, static, or $this Value is an object. This is reserved for cases where you return $this from a method, and is resolved to the class on which the method is being called.
array Value is an array with arbitrary keys/values.
array<T>, T[] Value is an array with integer keys, and elements of type T where T can be any available type.
ClassName Value is an object of the given class.
A|B Value is of type A, or type B where A, and B are any available type.
mixed, or * Value is of any available type. We encourage you to avoid this type whenever you can.