diff --git a/rlp/decode.go b/rlp/decode.go
index 0fd104e32f..4f29f2fb03 100644
--- a/rlp/decode.go
+++ b/rlp/decode.go
@@ -308,9 +308,9 @@ func makeListDecoder(typ reflect.Type, tag tags) (decoder, error) {
 		}
 		return decodeByteSlice, nil
 	}
-	etypeinfo, err := cachedTypeInfo1(etype, tags{})
-	if err != nil {
-		return nil, err
+	etypeinfo := cachedTypeInfo1(etype, tags{})
+	if etypeinfo.decoderErr != nil {
+		return nil, etypeinfo.decoderErr
 	}
 	var dec decoder
 	switch {
@@ -469,9 +469,9 @@ func makeStructDecoder(typ reflect.Type) (decoder, error) {
 // the pointer's element type.
 func makePtrDecoder(typ reflect.Type) (decoder, error) {
 	etype := typ.Elem()
-	etypeinfo, err := cachedTypeInfo1(etype, tags{})
-	if err != nil {
-		return nil, err
+	etypeinfo := cachedTypeInfo1(etype, tags{})
+	if etypeinfo.decoderErr != nil {
+		return nil, etypeinfo.decoderErr
 	}
 	dec := func(s *Stream, val reflect.Value) (err error) {
 		newval := val
@@ -493,9 +493,9 @@ func makePtrDecoder(typ reflect.Type) (decoder, error) {
 // This decoder is used for pointer-typed struct fields with struct tag "nil".
 func makeOptionalPtrDecoder(typ reflect.Type) (decoder, error) {
 	etype := typ.Elem()
-	etypeinfo, err := cachedTypeInfo1(etype, tags{})
-	if err != nil {
-		return nil, err
+	etypeinfo := cachedTypeInfo1(etype, tags{})
+	if etypeinfo.decoderErr != nil {
+		return nil, etypeinfo.decoderErr
 	}
 	dec := func(s *Stream, val reflect.Value) (err error) {
 		kind, size, err := s.Kind()
@@ -816,12 +816,12 @@ func (s *Stream) Decode(val interface{}) error {
 	if rval.IsNil() {
 		return errDecodeIntoNil
 	}
-	info, err := cachedTypeInfo(rtyp.Elem(), tags{})
+	decoder, err := cachedDecoder(rtyp.Elem())
 	if err != nil {
 		return err
 	}
 
-	err = info.decoder(s, rval.Elem())
+	err = decoder(s, rval.Elem())
 	if decErr, ok := err.(*decodeError); ok && len(decErr.ctx) > 0 {
 		// add decode target type to error so context has more meaning
 		decErr.ctx = append(decErr.ctx, fmt.Sprint("(", rtyp.Elem(), ")"))
diff --git a/rlp/decode_test.go b/rlp/decode_test.go
index 503b581453..fa57182c99 100644
--- a/rlp/decode_test.go
+++ b/rlp/decode_test.go
@@ -702,6 +702,27 @@ func TestDecoderInByteSlice(t *testing.T) {
 	}
 }
 
+type unencodableDecoder func()
+
+func (f *unencodableDecoder) DecodeRLP(s *Stream) error {
+	if _, err := s.List(); err != nil {
+		return err
+	}
+	if err := s.ListEnd(); err != nil {
+		return err
+	}
+	*f = func() {}
+	return nil
+}
+
+func TestDecoderFunc(t *testing.T) {
+	var x func()
+	if err := DecodeBytes([]byte{0xC0}, (*unencodableDecoder)(&x)); err != nil {
+		t.Fatal(err)
+	}
+	x()
+}
+
 func ExampleDecode() {
 	input, _ := hex.DecodeString("C90A1486666F6F626172")
 
diff --git a/rlp/encode.go b/rlp/encode.go
index bd2c5aab8f..f255c38a9c 100644
--- a/rlp/encode.go
+++ b/rlp/encode.go
@@ -182,11 +182,11 @@ func (w *encbuf) Write(b []byte) (int, error) {
 
 func (w *encbuf) encode(val interface{}) error {
 	rval := reflect.ValueOf(val)
-	ti, err := cachedTypeInfo(rval.Type(), tags{})
+	writer, err := cachedWriter(rval.Type())
 	if err != nil {
 		return err
 	}
-	return ti.writer(rval, w)
+	return writer(rval, w)
 }
 
 func (w *encbuf) encodeStringHeader(size int) {
@@ -499,17 +499,17 @@ func writeInterface(val reflect.Value, w *encbuf) error {
 		return nil
 	}
 	eval := val.Elem()
-	ti, err := cachedTypeInfo(eval.Type(), tags{})
+	writer, err := cachedWriter(eval.Type())
 	if err != nil {
 		return err
 	}
-	return ti.writer(eval, w)
+	return writer(eval, w)
 }
 
 func makeSliceWriter(typ reflect.Type, ts tags) (writer, error) {
-	etypeinfo, err := cachedTypeInfo1(typ.Elem(), tags{})
-	if err != nil {
-		return nil, err
+	etypeinfo := cachedTypeInfo1(typ.Elem(), tags{})
+	if etypeinfo.writerErr != nil {
+		return nil, etypeinfo.writerErr
 	}
 	writer := func(val reflect.Value, w *encbuf) error {
 		if !ts.tail {
@@ -545,9 +545,9 @@ func makeStructWriter(typ reflect.Type) (writer, error) {
 }
 
 func makePtrWriter(typ reflect.Type) (writer, error) {
-	etypeinfo, err := cachedTypeInfo1(typ.Elem(), tags{})
-	if err != nil {
-		return nil, err
+	etypeinfo := cachedTypeInfo1(typ.Elem(), tags{})
+	if etypeinfo.writerErr != nil {
+		return nil, etypeinfo.writerErr
 	}
 
 	// determine nil pointer handler
@@ -579,7 +579,7 @@ func makePtrWriter(typ reflect.Type) (writer, error) {
 		}
 		return etypeinfo.writer(val.Elem(), w)
 	}
-	return writer, err
+	return writer, nil
 }
 
 // putint writes i to the beginning of b in big endian byte
diff --git a/rlp/encode_test.go b/rlp/encode_test.go
index 827960f7c1..6e49b89a85 100644
--- a/rlp/encode_test.go
+++ b/rlp/encode_test.go
@@ -49,6 +49,13 @@ func (e byteEncoder) EncodeRLP(w io.Writer) error {
 	return nil
 }
 
+type undecodableEncoder func()
+
+func (f undecodableEncoder) EncodeRLP(w io.Writer) error {
+	_, err := w.Write(EmptyList)
+	return err
+}
+
 type encodableReader struct {
 	A, B uint
 }
@@ -239,6 +246,8 @@ var encTests = []encTest{
 	{val: (*testEncoder)(nil), output: "00000000"},
 	{val: &testEncoder{}, output: "00010001000100010001"},
 	{val: &testEncoder{errors.New("test error")}, error: "test error"},
+	// verify that the Encoder interface works for unsupported types like func().
+	{val: undecodableEncoder(func() {}), output: "C0"},
 	// verify that pointer method testEncoder.EncodeRLP is called for
 	// addressable non-pointer values.
 	{val: &struct{ TE testEncoder }{testEncoder{}}, output: "CA00010001000100010001"},
diff --git a/rlp/typecache.go b/rlp/typecache.go
index 0041d1d7bd..ab5ee3da76 100644
--- a/rlp/typecache.go
+++ b/rlp/typecache.go
@@ -29,8 +29,10 @@ var (
 )
 
 type typeinfo struct {
-	decoder
-	writer
+	decoder    decoder
+	decoderErr error // error from makeDecoder
+	writer     writer
+	writerErr  error // error from makeWriter
 }
 
 // represents struct tags
@@ -56,12 +58,22 @@ type decoder func(*Stream, reflect.Value) error
 
 type writer func(reflect.Value, *encbuf) error
 
-func cachedTypeInfo(typ reflect.Type, tags tags) (*typeinfo, error) {
+func cachedDecoder(typ reflect.Type) (decoder, error) {
+	info := cachedTypeInfo(typ, tags{})
+	return info.decoder, info.decoderErr
+}
+
+func cachedWriter(typ reflect.Type) (writer, error) {
+	info := cachedTypeInfo(typ, tags{})
+	return info.writer, info.writerErr
+}
+
+func cachedTypeInfo(typ reflect.Type, tags tags) *typeinfo {
 	typeCacheMutex.RLock()
 	info := typeCache[typekey{typ, tags}]
 	typeCacheMutex.RUnlock()
 	if info != nil {
-		return info, nil
+		return info
 	}
 	// not in the cache, need to generate info for this type.
 	typeCacheMutex.Lock()
@@ -69,25 +81,20 @@ func cachedTypeInfo(typ reflect.Type, tags tags) (*typeinfo, error) {
 	return cachedTypeInfo1(typ, tags)
 }
 
-func cachedTypeInfo1(typ reflect.Type, tags tags) (*typeinfo, error) {
+func cachedTypeInfo1(typ reflect.Type, tags tags) *typeinfo {
 	key := typekey{typ, tags}
 	info := typeCache[key]
 	if info != nil {
 		// another goroutine got the write lock first
-		return info, nil
+		return info
 	}
 	// put a dummy value into the cache before generating.
 	// if the generator tries to lookup itself, it will get
 	// the dummy value and won't call itself recursively.
-	typeCache[key] = new(typeinfo)
-	info, err := genTypeInfo(typ, tags)
-	if err != nil {
-		// remove the dummy value if the generator fails
-		delete(typeCache, key)
-		return nil, err
-	}
-	*typeCache[key] = *info
-	return typeCache[key], err
+	info = new(typeinfo)
+	typeCache[key] = info
+	info.generate(typ, tags)
+	return info
 }
 
 type field struct {
@@ -106,10 +113,7 @@ func structFields(typ reflect.Type) (fields []field, err error) {
 			if tags.ignored {
 				continue
 			}
-			info, err := cachedTypeInfo1(f.Type, tags)
-			if err != nil {
-				return nil, err
-			}
+			info := cachedTypeInfo1(f.Type, tags)
 			fields = append(fields, field{i, info})
 		}
 	}
@@ -151,15 +155,9 @@ func lastPublicField(typ reflect.Type) int {
 	return last
 }
 
-func genTypeInfo(typ reflect.Type, tags tags) (info *typeinfo, err error) {
-	info = new(typeinfo)
-	if info.decoder, err = makeDecoder(typ, tags); err != nil {
-		return nil, err
-	}
-	if info.writer, err = makeWriter(typ, tags); err != nil {
-		return nil, err
-	}
-	return info, nil
+func (i *typeinfo) generate(typ reflect.Type, tags tags) {
+	i.decoder, i.decoderErr = makeDecoder(typ, tags)
+	i.writer, i.writerErr = makeWriter(typ, tags)
 }
 
 func isUint(k reflect.Kind) bool {