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Error Identifier: interface.duplicateEnumCase

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);

// This identifier is produced by the DuplicateDeclarationRule which uses the
// class type description as prefix. In practice, interfaces cannot have enum
// cases, so this identifier is unlikely to be encountered in valid PHP code.
// The rule applies uniformly to all class-like declarations.

enum Status
{
	case Active;
	case Active;
}

Why is it reported? #

The declaration contains the same enum case name more than once. PHP does not allow redeclaring an enum case within the same body. This will cause a fatal error at runtime.

While the interface. prefix suggests this applies to interfaces, this identifier is generated by a generic rule that prefixes the error with the class-like type description. Interfaces cannot have enum cases in valid PHP, so this error is primarily relevant to enums themselves (where the identifier would be enum.duplicateEnumCase).

How to fix it #

Remove the duplicate enum case or rename it:

 <?php declare(strict_types = 1);
 
 enum Status
 {
 	case Active;
-	case Active;
+	case Inactive;
 }

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]

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