Returns false if lhs == WithNaN.defaultValue!Lhs, lhs == rhs otherwise.
The left-hand side of the comparison (Lhs is the first argument to Checked)
The right-hand side of the comparison
lhs != WithNaN.defaultValue!Lhs && lhs == rhs
See Implementation
Returns false if lhs == WithNaN.defaultValue!Lhs, lhs == rhs otherwise.