fmt: Printf, %s output of nil get poisoned by struct pointers

[gopherbot]

by jakzale:

What steps will reproduce the problem?
If possible, include a link to a program on play.golang.org.
1. Print nil using %s placeholder after printing a structure  or a pointer using %s
placeholder
2. http://play.golang.org/p/0XwuksmHud

What is the expected output?
%!s(<nil>) %!s(*main.A=<nil>) %!s(<nil>) {} %!s(<nil>)

What do you see instead?
%!s(<nil>) %!s(*main.A=<nil>) %!s(*main.A=<nil>) {} %!s(main.B={})

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

Which operating system are you using?
Mac OSX 10.7.4

Which version are you using?  (run 'go version')
go version go1.0.2

Please provide any additional information below.

[robpike]

Comment 1:

Labels changed: added priority-later, removed priority-triage.

Owner changed to @robpike.

Status changed to Accepted.

[rsc]

Comment 2:

Ouch.

[robpike]

Comment 3:

This issue was closed by revision a308be5.

Status changed to Fixed.