Computation of the derivative of a polynomial is wrong (from gforge #21592)
Imported issue: Initially reported by @chevilla in https://gforge.inria.fr/tracker/?group_id=1015&aid=21592
In the following session, the returned derivative is the opposite as what it should be:
p = 3 * (x - 1) - 7 * (x - 1)^2;
canonical=on!;
p;
-10 + 17 * x + -7 * x^2
diff(p);
-17 + 14 * x