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

$ go version
go version go1.13.2 linux/amd64

And for the x/tools repo:

$ git rev-parse HEAD
8456940

Does this issue reproduce with the latest release?

Yes.

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

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN="/home/user/bin"
GOCACHE="/home/user/.cache/go-build"
GOENV="/home/user/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/user"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/user/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/user/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/user/src/golang.org/x/tools/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-build399397170=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Make a present .slide file with a .play line pointing at a go file in a directory with a directory with a go.mod file specifying a non-tip dependency version.

What did you expect to see?

The behaviour of the code with the specified dependency version (seen here https://play.golang.org/p/UQFVOCI5ehs - failure to terminate).

What did you see instead?

Correct termination with the expected error (not reproducible on the playground since the code actively waits for 10 seconds, so it times out).

Additional information

This feature is available on the playground as seen above (and commented here). The issue is that the go.mod file is not moved with the code and the playground/socket package does not have the same feature for handling go.mod information as the play.golang.org site does.