diff --git a/src/reader.rs b/src/reader.rs
index 872cdb49..d2ff5c23 100644
--- a/src/reader.rs
+++ b/src/reader.rs
@@ -14,10 +14,6 @@
  * limitations under the License.
  */
 
-//package com.google.zxing;
-
-use std::collections::HashMap;
-
 use crate::{common::Result, Binarizer, BinaryBitmap, DecodingHintDictionary, RXingResult};
 
 /**
@@ -70,9 +66,12 @@ pub trait Reader {
      */
     fn reset(&mut self) { /* do nothing */
     }
+}
 
+#[cfg( feature = "experimental_features")]
+pub trait ImmutableReader {
     fn immutable_decode<B: Binarizer>(&self, image: &mut BinaryBitmap<B>) -> Result<RXingResult> {
-        self.immutable_decode_with_hints(image, &HashMap::default())
+        self.immutable_decode_with_hints(image, &DecodingHintDictionary::default())
     }
 
     fn immutable_decode_with_hints<B: Binarizer>(
@@ -82,4 +81,4 @@ pub trait Reader {
     ) -> Result<RXingResult> {
         unimplemented!()
     }
-}
+}
\ No newline at end of file