R devel - Jul 2010 - "Undocumented code objects" message from missing alias

If I omit the \alias{houseprices} from the second line of a data
documentation file houseprices.Rd, R CMD check gives the warning message:

"
Undocumented code objects:
 houseprices
All user-level objects in a package should have documentation entries.
See the chapter 'Writing R documentation files' in manual 'Writing R
Extensions'.
"

I can build the package without error, but the help file for houseprices
is missing.  It would be good to have a message that gives a more
direct indication of what is wrong.

Running R CMD check on the directory at 
http://www.maths.anu.edu.au/~johnm/r/packages/testpkg
demonstrates the point.

John Maindonald             email: john.maindonald at anu.edu.au
phone : +61 2 (6125)3473    fax  : +61 2(6125)5549
Centre for Mathematics & Its Applications, Room 1194,
John Dedman Mathematical Sciences Building (Building 27)
Australian National University, Canberra ACT 0200.
http://www.maths.anu.edu.au/~johnm