cmd/compile: unexpected character in for clause causes misleading error

[0xmohit]

What version of Go are you using (go version)?

go version go1.7.1 linux/amd64

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH=""
GORACE=""
GOROOT="/usr/local/go"
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build433231288=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"

What did you do?

https://play.golang.org/p/nALNrCVtmz

What did you expect to see?

Something suggesting that ) was unexpected.

Using go 1.5.3, one would see:

# command-line-arguments
./t.go:5: syntax error: unexpected ), expecting {

What did you see instead?

# command-line-arguments
./t.go:5: syntax error: missing { after for clause

The current error isn't as helpful as it was.

[rsc]

It does seem like an error worth improving.

[gopherbot]

CL https://golang.org/cl/36636 mentions this issue.

[gopherbot]

CL https://golang.org/cl/36637 mentions this issue.