diff --git a/vendor/cmd/go/internal/modfile/rule.go b/vendor/cmd/go/internal/modfile/rule.go
index 3170146..24bae6b 100644
--- a/vendor/cmd/go/internal/modfile/rule.go
+++ b/vendor/cmd/go/internal/modfile/rule.go
@@ -431,7 +431,7 @@
 			if len(stmt.Token) > 0 && stmt.Token[0] == "require" {
 				var newLines []*Line
 				for _, line := range stmt.Line {
-					if p, err := strconv.Unquote(line.Token[0]); err == nil && need[p] != "" {
+					if p, err := parseString(&line.Token[0]); err == nil && need[p] != "" {
 						line.Token[1] = need[p]
 						delete(need, p)
 						newLines = append(newLines, line)
@@ -445,7 +445,7 @@
 
 		case *Line:
 			if len(stmt.Token) > 0 && stmt.Token[0] == "require" {
-				if p, err := strconv.Unquote(stmt.Token[1]); err == nil && need[p] != "" {
+				if p, err := parseString(&stmt.Token[1]); err == nil && need[p] != "" {
 					stmt.Token[2] = need[p]
 					delete(need, p)
 				} else {
diff --git a/vendor/cmd/go/vgo_test.go b/vendor/cmd/go/vgo_test.go
index df360bf..5fd8469 100644
--- a/vendor/cmd/go/vgo_test.go
+++ b/vendor/cmd/go/vgo_test.go
@@ -693,3 +693,39 @@
 	tg.cd(tg.path("x"))
 	tg.run("-vgo", "build")
 }
+
+func TestModSyncPrintJson(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.makeTempdir()
+
+	tg.setenv("GOPATH", tg.path("."))
+	tg.must(os.MkdirAll(tg.path("x"), 0777))
+	tg.must(ioutil.WriteFile(tg.path("x/main.go"), []byte(`
+		package x
+		import "github.com/gorilla/mux"
+		func main() {
+			_ := mux.NewRouter()
+		}`), 0666))
+	tg.must(ioutil.WriteFile(tg.path("x/go.mod"), []byte("module x"), 0666))
+	tg.cd(tg.path("x"))
+	tg.run("-vgo", "mod", "-sync", "-json")
+	count := tg.grepCountBoth(`"Path": "github.com/gorilla/mux",`)
+	if count != 1 {
+		t.Fatal("produces duplicate imports")
+	}
+	// test quoted module path
+	tg.must(ioutil.WriteFile(tg.path("x/go.mod"), []byte(`
+		module x
+		require (
+			"github.com/gorilla/context" v1.1.1
+			"github.com/gorilla/mux" v1.6.2
+	)`), 0666))
+	tg.run("-vgo", "mod", "-sync", "-json")
+	count = tg.grepCountBoth(`"Path": "github.com/gorilla/mux",`)
+	if count != 1 {
+		t.Fatal("produces duplicate imports")
+	}
+
+}