It seems at the moment Query Builder silently chooses only 1st value from array when array value given. There is no exception thrown so this could lead to potential risky situations when code doesn't behave as it should if by mistake you pass array to where method.

For example at the moment when you use code like this:

User::where('id', [5,2])->get();
User::where('id', '<>', [5,2])->get();

builder will generate queries like those:

select * from `users` where `id` = 5;
select * from `users` where `id` <> 5;

If this PR were accepted in case of developer error using such code, Builder would automatically fallback to whereIn and whereNotIn methods when possible.

I believe this change could potentially affect existing applications so it's better to target it to 7.x instead of 6.x