Warning: Failed prop type: Invalid prop iconPosition of value right supplied to Input, expected one of ["left"].
It doesn't accept right because it's right by default:
<Input /> // equals to <Input iconPosition='right' />
So, it's doesn't make sence. Also, SUI's css doesn't have class for right.
but how to deal with the iconPosition in RTL?
As if we are giving the iconPosition = 'left' in the input then its moving to right in RTL.
if we are using the default position for icons in the rightside then its position is not changing in RTL, ideally it should move to left.
but if I am providing the iconPosition ='right', it works fine in the RTL but I am getting the above logged warning.
I don't understand your problem. If you need icon on right, don't set iconPosition prop.
However, possible there is another behaviour in RTL SUI.
<Input icon='users' />

<Input icon='users' iconPosition='left' />

<Input icon='users' />

<Input icon='users' iconPosition='left' />

I want the same icon which has a default position (right) in LTR to shift to Left in RTL. which is not happening untill I provide the iconPosition = 'right' in LTR.
I think there might be a valid issue here. Could you create a codepen that demonstrates the problem? Fork this to get started: codepen.io/levithomason/pen/ZpBaJX
@levithomason made an example here: https://codepen.io/mcfoton/pen/wmLxeY?editors=0010 will that do?
I also believe this is a valid issue. If I want to apply custom css to the input part of the input box, I have to split the input box like so:
<Input>
<input className='custom'/>
<Icon name='calendar'/>
</Input>
...which looks like:

...but if I apply the iconPosition='right' flag like so:
<Input iconPosition='right'>
<input className='custom'/>
<Icon name='calendar'/>
</Input>
...it looks like:

...but then I get a PropTypes exception.
It's strange that this issue doesn't contain my reply. Correct usage for the children API:
<Input icon>
<input className="custom" />
<Icon name="calendar" />
</Input>
Most helpful comment
It doesn't accept
rightbecause it's right by default:So, it's doesn't make sence. Also, SUI's css doesn't have class for
right.