make/O/N=3 lhs, rhs
lhs = p
rhs = 10 + p
print lhs
print rhs
lhs[inf] = rhs
this is not good code. rhs is using implicit [p] here, see DisplayHelpTopic "Mismatched Waves" but that is suprising. It get's even worse for multidimensional waves, see DisplayHelpTopic "Multidimensional Wave Assignment" the "Important note".