Error Identifier: classConstant.nonFinal

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);

trait HasVersion
{
    final public const VERSION = '1.0';
}

class App
{
    use HasVersion;

    public const VERSION = '1.0';
}

Why is it reported? #

The class declares a constant that overrides a final constant from a used trait, but does not declare it as final as well. When a trait defines a constant as final, any class that uses the trait and redeclares that constant must also declare it as final. This is a PHP language constraint for trait constant inheritance.

How to fix it #

Add the final keyword to the overriding constant:

 <?php declare(strict_types = 1);
 
 class App
 {
     use HasVersion;

-    public const VERSION = '1.0';
+    final public const VERSION = '1.0';
 }

Or remove the redeclaration and let the trait constant be inherited:

 <?php declare(strict_types = 1);
 
 class App
 {
     use HasVersion;
-
-    public const VERSION = '1.0';
 }

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\Traits\ConflictingTraitConstantsRule [1]

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