#529 NaN ne NaN is false

[Michael Kay]

The result of the comparison (NaN ne NaN) should be
true, but is currently false. The same problem occurs
if the != operator is used.

Source fix: in ValueComparison.java, method compare(),
line 500, change

if (v1 instanceof NumericValue &&
((NumericValue)v1).isNaN()) {
return false;
}

to:

if (v1 instanceof NumericValue &&
((NumericValue)v1).isNaN()) {
if (op == Token.FNE && v2 instanceof
NumericValue && ((NumericValue)v2).isNaN()) {
return true;
}
return false;
}

[Michael Kay]

Logged In: YES
user_id=251681

Correction to fix. The previous fix does not cover all
cases. The rule is that if either operand of "ne" or "!=" is
NaN, the result is true. So the code at the start of the
compare() method should be changed from:

if (v1 instanceof NumericValue && ((NumericValue)v1).isNaN()) {
return false;
}
if (v2 instanceof NumericValue &&
((NumericValue)v2).isNaN()) {
return false;
}

to:

if (v1 instanceof NumericValue && ((NumericValue)v1).isNaN()) {
return (op == Token.FNE);
}
if (v2 instanceof NumericValue &&
((NumericValue)v2).isNaN()) {
return (op == Token.FNE);
}