cmd/compile: confusing compiler error when using if instead of for with range operator inside anonymous function

[mzimmerman]

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

$ go version
go version go1.14.2 linux/amd64

Does this issue reproduce with the latest release?

Yes

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/mezimm00/.cache/go-build"
GOENV="/home/mezimm00/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/mezimm00/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/go-1.14"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go-1.14/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/mezimm00/machine/src/createI2chart/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build527871476=/tmp/go-build -gno-record-gcc-switches"

What did you do?

https://play.golang.org/p/DJKZqMtng4S

What did you expect to see?

syntax error: unexpected range, expecting expression

What did you see instead?

expression in go must be function call

When I typically see this error it's because I forgot the () on an anonymous function. In this case I didn't though. Instead, this error is reported when there was an error inside the anonymous function; that being using an if instead of the intended for with the range operator.

[andybons]

@randall77 @griesemer @josharian @mdempsky @martisch

[griesemer]

Thanks for the report. This looks like a problem with the parser recovering gracefully in the presence of the syntax error (use of range inside an if).