Queries whether a Checked!(T, WithNaN) object is not a number (NaN).
the Checked instance queried
true if x is a NaN, false otherwise
auto x1 = Checked!(int, WithNaN)(); assert(x1.isNaN); x1 = 1; assert(!x1.isNaN); x1 = x1.init; assert(x1.isNaN);
See Implementation
Queries whether a Checked!(T, WithNaN) object is not a number (NaN).