What does 'go version' print?
go version go1.4beta1 linux/amd64

What steps reproduce the problem?
go test go/parser -test.cpu=4,4,4

What happened?
--- FAIL: TestErrors-4 (0.00s)
panic: testdata/commas.src used multiple times [recovered]
    panic: testdata/commas.src used multiple times

goroutine 18 [running]:
testing.func·006()
    /home/gustav/go.tip/src/testing/testing.go:441 +0x181
go/parser.func·004(0xc208046b40, 0x1)
    /home/gustav/go.tip/src/go/parser/error_test.go:44 +0x10f
go/token.(*FileSet).Iterate(0xc208034440, 0xc2080b5c30)
    /home/gustav/go.tip/src/go/token/position.go:396 +0xb2
go/parser.getFile(0xc208206fc0, 0x13, 0xc2080461e0)
    /home/gustav/go.tip/src/go/parser/error_test.go:49 +0x65
go/parser.expectedErrors(0xc208038000, 0xc208206fc0, 0x13, 0xc208036380, 0x165, 0x365,
0xc208208801)
    /home/gustav/go.tip/src/go/parser/error_test.go:78 +0x7d
go/parser.checkErrors(0xc208038000, 0xc208206fc0, 0x13, 0x0, 0x0)
    /home/gustav/go.tip/src/go/parser/error_test.go:165 +0x3eb
go/parser.TestErrors(0xc208038000)
    /home/gustav/go.tip/src/go/parser/error_test.go:179 +0x471
testing.tRunner(0xc208038000, 0x67f500)
    /home/gustav/go.tip/src/testing/testing.go:447 +0xbf
created by testing.RunTests
    /home/gustav/go.tip/src/testing/testing.go:555 +0xa8b

goroutine 1 [chan receive]:
testing.RunTests(0x5f4518, 0x67f500, 0xd, 0xd, 0x681d01)
    /home/gustav/go.tip/src/testing/testing.go:556 +0xad6
testing.(*M).Run(0xc208056140, 0x67b9c0)
    /home/gustav/go.tip/src/testing/testing.go:485 +0x6c
main.main()
    go/parser/_test/_testmain.go:82 +0x1d5
FAIL    go/parser   0.022s

What should have happened instead?
=== RUN TestErrors-2
--- PASS: TestErrors-2 (0.00s)