[Rd] NA %*% 0 == 0 (PR#4582)

[hosking at watson.ibm.com]

Full_Name: J . R. M. Hosking
Version: 1.8.0
OS: Windows 2000
Submission from: (NULL) (129.34.20.23)


On R 1.8.0 (and on R 1.5.1), Windows binary:

> NA %*% 0
     [,1]
[1,]    0

This is surprising.  Is it a bug?  Note that 

> 0 %*% NA
     [,1]
[1,]   NA
> NA %*% 1
     [,1]
[1,]   NA
> NA * 0
[1] NA

as expected.