by vegard.nossum:

What steps will reproduce the problem?

1. Create a file segfault.go with the following contents (1 line):

func (a b, c d) x ()

2. Run "6g segfault.go"

What is the expected output? What do you see instead?

$ 6g segfault.go 
Segmentation fault

What is your $GOOS?  $GOARCH?

declare -x GOARCH="amd64"
declare -x GOOS="linux"

Which revision are you sync'ed to?  (hg log -l 1)

$ hg log -l 1
changeset:   4015:cb140bac9ab0
tag:         tip
user:        Russ Cox <rsc@golang.org>
date:        Thu Nov 12 14:55:26 2009 -0800
summary:     test/run: unset GREP_OPTIONS


valgrind output suggests something wrong in the parser:

==582== Invalid read of size 8
==582==    at 0x42B87B: yyparse (go.y:1120)
==582==    by 0x42FEC7: p9main (lex.c:91)
==582==    by 0x434038: main (main.c:35)
==582==  Address 0x20 is not stack'd, malloc'd or (recently) free'd