What steps will reproduce the problem?
If possible, include a link to a program on play.golang.org.
1. Compile http://play.golang.org/p/MlxBDNUgP6
2.
3.

What is the expected output?
./foo.go:8: cannot use i (type *C.int) as type C.size_t in function argument

What do you see instead?
cannot use i (type *_Ctype_int) as type C.size_t in function argument

Which compiler are you using (5g, 6g, 8g, gccgo)?
6g

Which operating system are you using?
Linux

Which version are you using?  (run 'go version')
go version devel +341a490e4736 Fri Nov 08 11:31:44 2013 -0500 linux/amd64

Please provide any additional information below.
Using the type names that cgo uses internally doesn't help in understanding the, at
times, already not that easy to understand errors that cgo produces. This can especially
trip up people who are experimenting with cgo for the first time.

The issue is made worse by the fact that half of the error uses the internal format
(`*_Ctype_int`) while the other half uses the same format as used in actual Go code
(`C.size_t`)