3 files changed, 64 insertions, 2 deletions
diff --git a/src/cmd/compile/internal/gc/reflect.go b/src/cmd/compile/internal/gc/reflect.go
index 0341ccabfa..06083cafc7 100644
--- a/src/cmd/compile/internal/gc/reflect.go
+++ b/src/cmd/compile/internal/gc/reflect.go
@@ -1321,8 +1321,15 @@ ok:
 		// As the name suggests, this is an awful kludge, but it is
 		// limited to the dev.boringcrypto branch and avoids
 		// much more invasive effects elsewhere.
-		omitFieldForAwfulBoringCryptoKludge := func(t *types.Field) bool {
-			return strings.HasPrefix(myimportpath, "crypto/") && t.Sym != nil && t.Sym.Name == "boring"
+		omitFieldForAwfulBoringCryptoKludge := func(t *Field) bool {
+			if t.Sym == nil || t.Sym.Name != "boring" || t.Sym.Pkg == nil {
+				return false
+			}
+			path := t.Sym.Pkg.Path
+			if t.Sym.Pkg == localpkg {
+				path = myimportpath
+			}
+			return strings.HasPrefix(path, "crypto/")
 		}
 
 		n := 0
diff --git a/src/internal/boringtest/boring.go b/src/internal/boringtest/boring.go
new file mode 100644
index 0000000000..bea1276e69
--- /dev/null
+++ b/src/internal/boringtest/boring.go
@@ -0,0 +1,8 @@
+// Copyright 2017 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.
+
+// Nothing to see here but the tests.
+// This file keeps 'go install internal/...' working.
+
+package boring
diff --git a/src/internal/boringtest/boring_test.go b/src/internal/boringtest/boring_test.go
new file mode 100644
index 0000000000..a6b07eda70
--- /dev/null
+++ b/src/internal/boringtest/boring_test.go
@@ -0,0 +1,47 @@
+// Copyright 2017 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.
+
+// Like crypto/rsa/boring_test.go but outside the crypto/ tree.
+// Tests what happens if a package outside the crypto/ tree
+// "adopts" a struct definition. This happens in golang.org/x/crypto/ssh.
+
+package boring
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/asn1"
+	"reflect"
+	"testing"
+)
+
+type publicKey rsa.PublicKey
+
+func TestBoringASN1Marshal(t *testing.T) {
+	k, err := rsa.GenerateKey(rand.Reader, 128)
+	if err != nil {
+		t.Fatal(err)
+	}
+	pk := (*publicKey)(&k.PublicKey)
+	// This used to fail, because of the unexported 'boring' field.
+	// Now the compiler hides it [sic].
+	_, err = asn1.Marshal(*pk)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestBoringDeepEqual(t *testing.T) {
+	k0, err := rsa.GenerateKey(rand.Reader, 128)
+	if err != nil {
+		t.Fatal(err)
+	}
+	k := (*publicKey)(&k0.PublicKey)
+	k2 := *k
+	rsa.EncryptPKCS1v15(rand.Reader, (*rsa.PublicKey)(&k2), []byte("hello")) // initialize hidden boring field
+	if !reflect.DeepEqual(k, &k2) {
+		// compiler should be hiding the boring field from reflection
+		t.Fatalf("DeepEqual compared boring fields")
+	}
+}