x/tools/gopls: undeclared name when accessing symbols from other files

[lotsofone]

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

$ go version
go version go1.13.4 darwin/amd64

Does this issue reproduce with the latest release?

Yes. I installed the latest stable vscode build and golang.

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/jingmaoli/Library/Caches/go-build"
GOENV="/Users/jingmaoli/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/jingmaoli/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
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 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/t7/5wks8wmd113bd2vmxyht_hz18wqkb5/T/go-build555277668=/tmp/go-build -gno-record-gcc-switches -fno-common"

The output of gopls version and gopls -rpc.trace -v check /path/to/file.go?

$ gopls version
golang.org/x/tools/gopls v0.1.7
    golang.org/x/tools/gopls@v0.1.7 h1:YwKf8t9h69++qCtVmc2q6fVuetFXmmu9LKoPMYLZid4=
$ cd newproject
$ gopls -rpc.trace -v check ./main.go
2019/11/04 16:37:45 Info:2019/11/04 16:37:45 Build info
----------
golang.org/x/tools/gopls v0.1.7
    golang.org/x/tools/gopls@v0.1.7 h1:YwKf8t9h69++qCtVmc2q6fVuetFXmmu9LKoPMYLZid4=
    golang.org/x/sync@v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU=
    golang.org/x/tools@v0.0.0-20190918214516-5a1a30219888 h1:ER45Jz0UDQ3e6em1lwXVwuPf96lvyQogb7m+gEbsoPg=
    golang.org/x/xerrors@v0.0.0-20190717185122-a985d3407aa7 h1:9zdDQZ7Thm29KFXgAX/+yaf3eVbP7djjWp/dXAppNCc=

Go info
-------
go version go1.13.4 darwin/amd64

GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/jingmaoli/Library/Caches/go-build"
GOENV="/Users/jingmaoli/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/jingmaoli/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
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 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/t7/5wks8wmd113bd2vmxyht_hz18wqkb5/T/go-build468474295=/tmp/go-build -gno-record-gcc-switches -fno-common"
2019/11/04 16:37:45 Info:2019/11/04 16:37:45 17.284317ms for GOROOT= GOPATH= GO111MODULE= PWD=/Users/jingmaoli/Documents/newproject go "env" "GOMOD", stderr: <<>>
2019/11/04 16:37:45 Info:2019/11/04 16:37:45 17.996129ms for GOROOT= GOPATH= GO111MODULE= PWD=/Users/jingmaoli/Documents/newproject go "list" "-m" "-json" "all", stderr: <>
2019/11/04 16:37:45 Info:2019/11/04 16:37:45 19.629816ms for GOROOT= GOPATH= GO111MODULE= PWD=/Users/jingmaoli/Documents/newproject go "list" "-e" "-json" "-compiled=true" "-test=true" "-export=false" "-deps=true" "-find=false" "--" "builtin", stderr: <<>>
2019/11/04 16:37:45 Info:2019/11/04 16:37:45 15.675241ms for GOROOT= GOPATH= GO111MODULE= PWD=/Users/jingmaoli/Documents/newproject go "env" "GOPATH", stderr: <<>>
2019/11/04 16:37:45 Info:2019/11/04 16:37:45 15.213536ms for GOROOT= GOPATH= GO111MODULE= PWD=/Users/jingmaoli/Documents/newproject go "env" "GOMOD", stderr: <<>>
2019/11/04 16:37:45 Info:2019/11/04 16:37:45 15.515843ms for GOROOT= GOPATH= GO111MODULE= PWD=/Users/jingmaoli/Documents/newproject go "list" "-m" "-json" "all", stderr: <>
2019/11/04 16:37:46 Info:2019/11/04 16:37:46 16.533368ms for GOROOT= GOPATH= GO111MODULE= PWD=/Users/jingmaoli/Documents/newproject go "env" "GOPATH", stderr: <<>>
2019/11/04 16:37:46 Info:2019/11/04 16:37:46 16.029362ms for GOROOT= GOPATH= GO111MODULE= PWD=/Users/jingmaoli/Documents/newproject go "list" "-e" "-json" "-compiled=true" "-test=true" "-export=false" "-deps=true" "-find=false" "--" "/Users/jingmaoli/Documents/newproject", stderr: <<>>
2019/11/04 16:37:46 Info:2019/11/04 16:37:46 67.525425ms for GOROOT= GOPATH= GO111MODULE= PWD=/Users/jingmaoli/Documents/newproject go "list" "-e" "-json" "-compiled=true" "-test=true" "-export=false" "-deps=true" "-find=false" "--" "/Users/jingmaoli/Documents/newproject/main.go", stderr: <<>>
2019/11/04 16:37:46 Info:2019/11/04 16:37:46 go/packages.Load
	packages = 1
2019/11/04 16:37:46 Info:2019/11/04 16:37:46 go/packages.Load
	package = command-line-arguments
	files = [/Users/jingmaoli/Documents/newproject/main.go]
/Users/jingmaoli/Documents/newproject/main.go:4:2-3: undeclared name: f

What did you do?

1.create a folder called "newproject" and use vscode to open it
2.create main.go

package main

func main() {
	f()
}

3.create f.go

package main

import "fmt"

func f() {
	fmt.Println("Hello")
}

What did you expect to see?

No error should show up

What did you see instead?

No error occurs when running the following command

cd newproject
go build
./newproject

it will output 'Hello'
but in the vscode editor, it shows "undeclared name: f"

[gopherbot]

Thank you for filing a gopls issue! Please take a look at the Troubleshooting guide, and make sure that you have provided all of the relevant information here.

[stamblerre]

It looks like you are not working in your GOPATH, and you have not initialized a module. gopls will only work with multiple files in a package if you have initialized a module.

[lotsofone]

It looks like you are not working in your GOPATH, and you have not initialized a module. gopls will only work with multiple files in a package if you have initialized a module.

Does it mean I need to put my 'newproject' into $GOPATH/src/ to let gopls work?

[lotsofone]

Sorry I just tried 'go mod init somename' and gopls works. This should not be an issue.