inaccurate value on Slider and RangeSlider

Slider and RangeSlider in Controls 2 get inaccurate value when it is used in below cases.

// Slider
Slider {
    from: -10
    to: 10
    stepSize: 0.1
    snapMode: Slider.SnapAlways
    onValueChanged: {
        console.log(value)
    }
}

I expect the value changes like ... -0.3, -0.2, -0.1, 0.0, 0.1, 0.2, 0.3 ...

but actual result is like this.

qml: 1.1000000000000014
qml: 1.3000000000000007
qml: 1.4000000000000004
qml: 1.5
qml: 1.6000000000000014
qml: 1.8000000000000007
qml: 1.9000000000000004
qml: 2
qml: 2.1000000000000014
qml: 2.3000000000000007

 I know that the native logic is performing decimal operations using internal position value between 0.0 ~ 1.0, then the result of decimal operation can be like that.

Nevertheless,  Slider is providing a stepSize property that means the value will be changed at given stepSize gaps and also a user is expecting discrete value according to the stepSize.
It feels like an inaccurate value. If the stepSize is given, the lower decimal places than the stepSize's decimal places should be eliminated. 
 

The same problem occurs at RangeSlider. 

// RangeSlider
RangeSlider {
    from: -30
    to: 30 
    stepSize: 10
    first.value: -10
    second.value: 10
    snapMode: RangeSlider.SnapAlways
    first.onValueChanged: {
        console.log(first.value)
    }
    second.onValueChanged: {
        console.log(second.value)
    }
}

the results are below. we expect the value changes like 10, 20, 30 but

qml: 10
qml: 19.999999999999993
qml: 30
qml: 19.999999999999993
qml: 10

I think "valueAt" function in qquickslider.cpp, qquickrangeslider.cpp needs to be modified so that stepSize property can be considered.