Floating point math is imprecise because of the challenges of storing such values in a binary representation. Even worse, floating point math is
not associative; push a Float or a Double through a series of simple mathematical operations and the answer will be
different based on the order of those operation because of the rounding that takes place at each step.
Even simple floating point assignments are not simple:
var f: Float = 0.1 // 0.1000000014901161193847656
var d: Double = 0.1 // 0.1000000000000000055511151
Therefore, the use of the equality (==) and inequality (!=) operators on Float or Double values
is almost always an error.
This rule checks for the use of direct and indirect equality/inequailty tests on floats and doubles.
Noncompliant code example
var myNumber: Float = 0.3 + 0.6
if myNumber == 0.9 { // Noncompliant. Because of floating point imprecision, this will be false
// ...
}
if myNumber <= 0.9 && myNumber >= 0.9 { // Noncompliant indirect equality test
// ...
}
if myNumber < 0.9 || myNumber > 0.9 { // Noncompliant indirect inequality test
// ...
}
