Try

Author: VincentLanglet

src/Type/Doctrine/Descriptors/DecimalType.php

@@ -4,7 +4,9 @@
 
 use Doctrine\DBAL\Connection;
 use PHPStan\Doctrine\Driver\DriverDetector;
+use PHPStan\Type\Accessory\AccessoryLowercaseStringType;
 use PHPStan\Type\Accessory\AccessoryNumericStringType;
+use PHPStan\Type\Accessory\AccessoryUppercaseStringType;
 use PHPStan\Type\FloatType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\IntersectionType;
@@ -31,7 +33,12 @@ public function getType(): string
 
 	public function getWritableToPropertyType(): Type
 	{
-		return (new FloatType())->toString();
+		return new IntersectionType([
+			new StringType(),
+			new AccessoryNumericStringType(),
+			new AccessoryLowercaseStringType(),
+			new AccessoryUppercaseStringType(),
+		]);
 	}
 
 	public function getWritableToDatabaseType(): Type