by clbanning:

Before filing a bug, please check whether it has been fixed since the
latest release. Search the issue tracker and check that you're running the
latest version of Go:

Run "go version" and compare against
http://golang.org/doc/devel/release.html  If a newer version of Go exists,
install it and retry what you did to reproduce the problem.

Thanks.

What steps will reproduce the problem?
If possible, include a link to a program on play.golang.org.
http://play.golang.org/p/RQGcVFftK0

What is the expected output?
http://play.golang.org/p/49o-4SNGkb

s: main.docStruct{Tag:"Hello World"}
raw: <doc><tag>Hello World</tag></doc>
s: main.docStruct{Tag:"Hello Again"}
raw: <doc><tag>Hello Again</tag></doc>

What do you see instead?

s: main.docStruct{Tag:"Hello World"}
raw: <doc><tag>Hello
World</tag></doc><doc><tag>Hello Again</tag></doc>

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

Which operating system are you using?
OS X 10.9.1

Which version are you using?  (run 'go version')
go version go1.2 darwin/amd64

Please provide any additional information below.

The comment on d.switchToReader (encoding/xml/xml.go line 314) says that it wants to use
an io.ByteReader for speed - OK.
 However, then please document that if you want xml.Decoder to use the actual io.Reader passed to xml.NewDecoder,  then it must satisfy the io.ByteReader interface, as well.