Please answer these questions before submitting your issue. Thanks!

What did you do?

go get github.com/rogpeppe/godeps
go get github.com/juju/juju/...
cd $GOPATH/src/github.com/juju/juju
git checkout ef17f71281d245540a9e5ed54a00095610ac0797
godeps -u dependencies.tsv
go test github.com/juju/juju/worker/uniter/runner/jujuc -run=xxx

What did you expect to see?

ok github.com/juju/juju/worker/uniter/runner/jujuc 2.145s [no tests to run]

What did you see instead?

# github.com/juju/juju/worker/uniter/runner/jujuc_test
./relation-ids_test.go:138: internal compiler error: value v78 still has 1 uses

goroutine 1 [running]:
runtime/debug.Stack(0x0, 0x0, 0x0)
/home/nate/go/src/runtime/debug/stack.go:24 +0x79
cmd/compile/internal/gc.Fatalf(0xab2af4, 0x1a, 0xc421c746a0, 0x2, 0x2)
/home/nate/go/src/cmd/compile/internal/gc/subr.go:165 +0x226
cmd/compile/internal/gc.(*ssaExport).Fatalf(0xdcbcf5, 0x9e7, 0xab2af4, 0x1a, 0xc421c746a0, 0x2, 0x2)
/home/nate/go/src/cmd/compile/internal/gc/ssa.go:4976 +0x5d
cmd/compile/internal/ssa.(*Config).Fatalf(0xc4224d8000, 0xc4000009e7, 0xab2af4, 0x1a, 0xc421c746a0, 0x2, 0x2)
/home/nate/go/src/cmd/compile/internal/ssa/config.go:343 +0x6e
cmd/compile/internal/ssa.(*Func).Fatalf(0xc42347c900, 0xab2af4, 0x1a, 0xc421c746a0, 0x2, 0x2)
/home/nate/go/src/cmd/compile/internal/ssa/func.go:413 +0x6b
cmd/compile/internal/ssa.(*Func).freeValue(0xc42347c900, 0xc4224da2d0)
/home/nate/go/src/cmd/compile/internal/ssa/func.go:128 +0x391
cmd/compile/internal/ssa.writebarrier(0xc42347c900)
/home/nate/go/src/cmd/compile/internal/ssa/writebarrier.go:193 +0x1659
cmd/compile/internal/ssa.Compile(0xc42347c900)
/home/nate/go/src/cmd/compile/internal/ssa/compile.go:68 +0x304
cmd/compile/internal/gc.buildssa(0xc42180dc20, 0x0)
/home/nate/go/src/cmd/compile/internal/gc/ssa.go:177 +0x8fe
cmd/compile/internal/gc.compile(0xc42180dc20)
/home/nate/go/src/cmd/compile/internal/gc/pgen.go:362 +0x204
cmd/compile/internal/gc.funccompile(0xc42180dc20)
/home/nate/go/src/cmd/compile/internal/gc/dcl.go:1292 +0xdc
cmd/compile/internal/gc.Main()
/home/nate/go/src/cmd/compile/internal/gc/main.go:460 +0x1f0d
main.main()
/home/nate/go/src/cmd/compile/main.go:50 +0xfe

FAIL github.com/juju/juju/worker/uniter/runner/jujuc [build failed]

Does this issue reproduce with the latest release (go1.7.4)?

Nope, compiles fine w/ 1.7.4.

System details

go version devel +5c9035a Fri Dec 2 19:19:03 2016 +0000 linux/amd64
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/nate"
GORACE=""
GOROOT="/home/nate/go"
GOTOOLDIR="/home/nate/go/pkg/tool/linux_amd64"
GCCGO="/usr/bin/gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build901479024=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
PKG_CONFIG="pkg-config"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
GOROOT/bin/go version: go version devel +5c9035a Fri Dec 2 19:19:03 2016 +0000 linux/amd64
GOROOT/bin/go tool compile -V: compile version devel +5c9035a Fri Dec 2 19:19:03 2016 +0000 X:framepointer
uname -sr: Linux 4.4.0-47-generic
LSB Version:	core-9.20160110ubuntu0.2-amd64:core-9.20160110ubuntu0.2-noarch:printing-9.20160110ubuntu0.2-amd64:printing-9.20160110ubuntu0.2-noarch:security-9.20160110ubuntu0.2-amd64:security-9.20160110ubuntu0.2-noarch
Distributor ID:	Ubuntu
Description:	Ubuntu 16.04.1 LTS
Release:	16.04
Codename:	xenial
/lib/x86_64-linux-gnu/libc.so.6: GNU C Library (Ubuntu GLIBC 2.23-0ubuntu4) stable release version 2.23, by Roland McGrath et al.
gdb --version: GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1