diff --git a/src/cmd/go/internal/modload/import.go b/src/cmd/go/internal/modload/import.go
index d7fca8fd2c..309d654987 100644
--- a/src/cmd/go/internal/modload/import.go
+++ b/src/cmd/go/internal/modload/import.go
@@ -126,6 +126,8 @@ func Import(path string) (m module.Version, dir string, err error) {
 		}
 		dir := filepath.Join(cfg.GOROOT, "src", path)
 		return module.Version{}, dir, nil
+	} else if pathIsStd && path == cfg.GOROOTsrc {
+		return module.Version{}, dir, errors.New("directory should not directly contain source files")
 	}
 
 	// -mod=vendor is special.
diff --git a/src/cmd/go/internal/modload/load.go b/src/cmd/go/internal/modload/load.go
index 89d906f194..b28776b81c 100644
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@@ -126,6 +126,12 @@ func ImportPathsQuiet(patterns []string, tags map[string]bool) []*search.Match {
 					// It's not strictly necessary but helpful to keep the checks.
 					if modRoot != "" && dir == modRoot {
 						pkg = targetPrefix
+						if modRoot == cfg.GOROOTsrc {
+							// A package in GOROOT/src would have an empty path.
+							// Keep the path as cfg.GOROOTsrc. We'll report an error in Import.
+							// See golang.org/issue/36587.
+							pkg = modRoot
+						}
 					} else if modRoot != "" && strings.HasPrefix(dir, modRoot+string(filepath.Separator)) && !strings.Contains(dir[len(modRoot):], "@") {
 						suffix := filepath.ToSlash(dir[len(modRoot):])
 						if strings.HasPrefix(suffix, "/vendor/") {
diff --git a/src/cmd/go/testdata/script/list_gofile_in_goroot.txt b/src/cmd/go/testdata/script/list_gofile_in_goroot.txt
new file mode 100644
index 0000000000..0a3b128eae
--- /dev/null
+++ b/src/cmd/go/testdata/script/list_gofile_in_goroot.txt
@@ -0,0 +1,46 @@
+# Return an error if the user tries to list a go source file directly in $GOROOT/src.
+# Tests golang.org/issue/36587
+
+mkdir $WORK/fakegoroot/src
+mkdir $WORK/fakegopath/src
+
+env GOROOT=$WORK/fakegoroot
+env GOPATH=$WORK/fakegopath
+
+cp go.mod $GOROOT/src/go.mod
+cp foo.go $GOROOT/src/foo.go
+
+go env GOROOT
+stdout $WORK(/|\\)fakegoroot
+
+# switch to GOROOT/src
+cd $GOROOT/src
+
+# GO111MODULE=on,GOROOT
+env GO111MODULE=on
+! go list ./...
+stderr 'directory should not directly contain source files'
+go list -e .
+go list -f '{{if .Error}}{{.Error.Err}}{{end}}' -e ./...
+stdout 'directory should not directly contain source files'
+
+# GO111MODULE=off,GOROOT
+env GO111MODULE=off
+go list ./...
+[!windows] stdout _$WORK/fakegoroot/src
+[windows] stdout fakegoroot/src # On windows the ":" in the volume name is mangled
+
+# switch to GOPATH/src
+cp $WORK/gopath/src/foo.go $GOPATH/src/foo.go
+cd $GOPATH/src
+
+# GO111MODULE=off,GOPATH
+env GO111MODULE=off
+go list ./...
+
+-- go.mod --
+module g
+
+go 1.14
+-- foo.go --
+package foo
\ No newline at end of file