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Error Identifier: enum.duplicateProperty

Every error reported by PHPStan has an error identifier. Here’s a list of all error identifiers. In PHPStan Pro you can see the error identifier next to each error and filter errors by their identifiers.

Code example #

<?php declare(strict_types = 1);

enum Suit: string
{
	case Hearts = 'hearts';

	// Enums cannot have properties, but if they could,
	// this rule also applies to classes and interfaces
}

This error is reported by the same rule that checks classes and interfaces for duplicate property declarations:

<?php declare(strict_types = 1);

class Foo
{
	public int $prop;
	public int $prop;
}

Why is it reported? #

A property with the same name is declared more than once in the same class or enum. PHP does not allow redeclaring properties within a single class definition. This also applies when a property is declared both as a regular property and as a constructor-promoted property.

How to fix it #

Remove the duplicate property declaration:

 class Foo
 {
 	public int $prop;
-	public int $prop;
 }

If using constructor promotion, remove the separate property declaration:

 class Foo
 {
-	public int $prop;
-
 	public function __construct(
 		public int $prop,
 	) {}
 }

Non-ignorable error #

This error cannot be ignored using @phpstan-ignore or the ignoreErrors configuration. Non-ignorable errors indicate code that would cause a crash or a fatal error at runtime, or a fundamental problem in the analysed code that must be addressed.

Rules that report this error #

  • PHPStan\Rules\Classes\DuplicateDeclarationRule [1] [2]

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