1 files changed, 53 insertions, 0 deletions
diff --git a/src/syscall/syscall_plan9_test.go b/src/syscall/syscall_plan9_test.go
new file mode 100644
index 0000000..c0b3af5
--- /dev/null
+++ b/src/syscall/syscall_plan9_test.go
@@ -0,0 +1,53 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package syscall_test
+
+import (
+	"syscall"
+	"testing"
+)
+
+// testalias checks for aliasing of error strings returned by sys1 and sys2,
+// which both call the function named fn in package syscall
+func testalias(t *testing.T, fn string, sys1, sys2 func() error) {
+	err := sys1().Error()
+	errcopy := string([]byte(err))
+	sys2()
+	if err != errcopy {
+		t.Errorf("syscall.%s error string changed from %q to %q\n", fn, errcopy, err)
+	}
+}
+
+// issue 13770: errors cannot be nested in Plan 9
+
+func TestPlan9Syserr(t *testing.T) {
+	testalias(t,
+		"Syscall",
+		func() error {
+			return syscall.Mkdir("/", 0)
+		},
+		func() error {
+			return syscall.Mkdir("#", 0)
+		})
+	testalias(t,
+		"Syscall6",
+		func() error {
+			return syscall.Mount(0, 0, "", 0, "")
+		},
+		func() error {
+			return syscall.Mount(-1, 0, "", 0, "")
+		})
+	// originally failed only on plan9_arm
+	testalias(t,
+		"seek",
+		func() error {
+			_, err := syscall.Seek(0, 0, -1)
+			return err
+		},
+		func() error {
+			_, err := syscall.Seek(-1, 0, 0)
+			return err
+		})
+}