while trying phpstan with laravel to learn strict rules for the model

class Feature extends Model
{
    protected $guarded = [];

    /**
     * @return BelongsToMany<Plan, Feature>
     */
    public function plans(): BelongsToMany
    {
        return $this->belongsToMany(Plan::class);
    }
}

 Method App\Models\Feature::plans() should return                    
         Illuminate\Database\Eloquent\Relations\BelongsToMany<App\Models\Plan,
         App\Models\Feature> but returns                                     
         Illuminate\Database\Eloquent\Relations\BelongsToMany<App\Models\Plan,
         $this(App\Models\Feature)>.                                         
         💡 Template type TDeclaringModel on class                           
            Illuminate\Database\Eloquent\Relations\BelongsToMany is not      
            covariant.