reflect: fix Copy of non-pointer array with size > 64bits

Author: Ben Krieger

src/reflect/value.go

@@ -72,11 +72,15 @@ func decomposeInterface(i interface{}) (unsafe.Pointer, unsafe.Pointer)
 
 func ValueOf(i interface{}) Value {
 	typecode, value := decomposeInterface(i)
-	return Value{
+	v := Value{
 		typecode: (*rawType)(typecode),
 		value:    value,
 		flags:    valueFlagExported,
 	}
+	if v.typecode.Kind() == Array && v.typecode.Size() > unsafe.Sizeof(uintptr(0)) {
+		v.flags |= valueFlagIndirect
+	}
+	return v
 }
 
 func (v Value) Interface() interface{} {

src/reflect/value_test.go

@@ -791,6 +791,24 @@ func TestClearMap(t *testing.T) {
 	}
 }
 
+func TestCopyArrayToSlice(t *testing.T) {
+	// Test copying array <=64 bits and >64bits
+	// See issue #4554
+	a8 := [8]byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08}
+	s8 := make([]byte, 8)
+	a9 := [9]byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09}
+	s9 := make([]byte, 9)
+
+	Copy(ValueOf(s8), ValueOf(a8))
+	if !bytes.Equal(s8, a8[:]) {
+		t.Errorf("copied slice %x does not match input array %x", s8, a8[:])
+	}
+	Copy(ValueOf(s9), ValueOf(a9))
+	if !bytes.Equal(s9, a9[:]) {
+		t.Errorf("copied slice %x does not match input array %x", s9, a9[:])
+	}
+}
+
 func TestIssue4040(t *testing.T) {
 	var value interface{} = uint16(0)