trait.duplicateConstant

Code example

<?php declare(strict_types = 1);

trait MyTrait
{
    public const FOO = 1;
    public const FOO = 2;
}

class Foo
{
    use MyTrait;
}

Why is it reported?

A constant with the same name is declared more than once within the same trait. PHP does not allow redeclaring a constant within the same class-like structure, and this will cause a fatal error at runtime.

Traits gained support for constants in PHP 8.2. Like classes, they cannot contain duplicate constant declarations.

How to fix it

Remove the duplicate constant declaration and keep only one:

 trait MyTrait
 {
     public const FOO = 1;
-    public const FOO = 2;
 }

If you need different constant values, give them different names:

 trait MyTrait
 {
     public const FOO = 1;
-    public const FOO = 2;
+    public const BAR = 2;
 }