MorphMany used with $withCount property insert an extra binding into the queries using a nested where

[Tucker-Eric]

• Laravel Version: 5.6.16
• PHP Version: 7.2
• Database Driver & Version: mysql

Description:

An extra binding is inserted into a query of a model that references a morphMany relationship in it's $withCount property when using a nested where() statement.

Steps To Reproduce:

class ParentModel extends Model 
{
    protected $table = 'parent';

    protected $withCount = ['children'];

    public function children()
    {
        return $this->morphMany(ChildModel::class, 'morphable');
    }
}

class ChildModel extends Model
{
    protected $table = 'child';
}

$parent = new ParentModel;

$query = $parent->newQuery()->where(function($q) {
    return $q->where(1,1);
});

$bindings = $query->getBindings();

Expected bindings:

['ParentModel', 1];

Expected query:

select `parent`.*, (select count(*) from `child` where `parent`.`id` = `child`.`morphable_id` and `child`.`morphable_type` = 'ParentModel') as `children_count` from `parent` where (1 = 1)

Actual Bindings

['ParentModel','ParentModel', 1];

Actual query:

select `parent`.*, (select count(*) from `child` where `parent`.`id` = `child`.`morphable_id` and `child`.`morphable_type` = 'ParentModel') as `children_count` from `parent` where (1 =  'ParentModel')

[staudenmeir]

This affects all relationship queries with WHERE bindings.

The problem is Model::newQueryWithoutScopes() adding $withCount to every query.
So the query received by Builder::where() contains the $withCount bindings.

There are multiple issues and PRs about $withCount causing problems for all kinds of queries:
#21472, #21464, #21153, #21116, #21468, #22239