Testing xCAS version 1.2.3-9 (2017)

[parisse]

There is denesting of sums without parenthesis (or with left parenthesis since it's the same) but not with right parenthesis.
d1:=a+(b+c);
size(d1);
d2:=(a+b)+c;
size(d2);
== checks that the internal representation of the symbolic objects are the same. Therefore d1==d2 returns false