Missing Property Type

ID

php.missing_property_type

Severity

info

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

Php

Tags

code_smell, type-safety

Description

Reports class properties declared without a type. Typed properties have existed since PHP 7.4 (public int $count;); an untyped property falls back to the implicit mixed type, so the engine cannot enforce what it holds.

Rationale

An untyped property can be assigned any value at any point, which makes the class state hard to reason about and lets an inconsistent value live silently until it causes a fault elsewhere. A declared type turns an invalid assignment into an immediate error and documents the property’s purpose. Constructor-promoted properties (__construct(public $label)) are properties too and are held to the same standard, and the legacy var $x; form is flagged because it is both untyped and outdated style.

<?php
class Account
{
    public $balance;            // FLAW — property has no type declaration
    private string $owner;      // OK — typed property

    public function __construct(
        public $label,          // FLAW — promoted property has no type
        private int $id         // OK — promoted typed property
    ) {
    }
}

Remediation

Declare the property’s type before the variable name: a scalar (int, float, string, bool), a class or interface, a nullable type (?Type), or a union (int|string). Convert var $x; declarations to a typed private/protected/public form.

References