[Rd] strange warning: data() error?

[Therneau, Terry M., Ph.D.]

A user asked me about this and I can't figure it out.

tmt% R
R Under development (unstable) (2018-04-09 r74565) -- "Unsuffered Consequences"
Copyright (C) 2018 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

 > library(survival)
 > data(cgd0)
Warning message:
In data(cgd0) : data set ‘cgd0’ not found

----

The data set is present and can be manipulated: data() is not required.  Other data sets 
in the survival package don't generate this message.

Terry T.