Cannot Instantiate Abstract Class

Why This Happens

Abstract classes are designed to be extended, not instantiated directly. They serve as base classes that define a contract for subclasses. If you try to use new on an abstract class, PHP throws this error. You need to create or use a concrete subclass.

The Problem

abstract class BaseRepository {
    abstract public function findAll(): array;
}
$repo = new BaseRepository(); // Cannot instantiate abstract class

The Fix

abstract class BaseRepository {
    abstract public function findAll(): array;
}

class UserRepository extends BaseRepository {
    public function findAll(): array {
        return ['Alice', 'Bob'];
    }
}
$repo = new UserRepository();

Step-by-Step Fix

1. 1

   Identify the abstract class

   Check which class the error references and confirm it is declared as abstract.

2. 2

   Find or create a concrete subclass

   Look for existing classes that extend the abstract class, or create a new one that implements all abstract methods.

3. 3

   Instantiate the concrete class

   Replace new AbstractClass() with new ConcreteClass() using the appropriate subclass for your use case.