[R] understanding I() in lmer formula

[Don Cohen]

The suggestion to post on R-sig-ME was a good one.
The problem turned out to be a bug in lmer parsing, which is now fixed.

S Ellison writes:
 > >  Is there a difference between I(x*y) and I(y*x) ?
 > > I have a call to lmer that results in this complaint:
 > >   Error in is.alpha2.subordinate * ~z.min.co.res :
 > 
 > A reproducible example would help ...