HUGE error on solveFor

[Matt0017]

a very simple

x*y+y=0

solved for x return two answers:
x=-1 (correct) and x=0 (incorrect)

[Matt0017]

Debugging I found that this was being transformed into

(x+1)*y
that first part gives the correct answer -1
but solving y for x returns 0, which may be the problem of a missing pair of parenthesis in Solve.js line 1328
if(eq.group === S || eq.group === CB && eq.contains(solve_for))
in this case
eq.group === S is true and eq.contains(solve_for) is false
but the whole condition is true