diff --git a/source/marathon/defl.rs b/source/marathon/defl.rs
index 2580240..0693647 100644
--- a/source/marathon/defl.rs
+++ b/source/marathon/defl.rs
@@ -202,7 +202,7 @@ fn stream_literal(v: &mut Vec<u8>, b: &[u8], p: usize) -> ResultS<usize>
    }
 
    p += 4;
-   v.extend_from_slice(ok!(b.get(p..p + len), "not enough data")?);
+   v.extend(ok!(b.get(p..p + len), "not enough data")?);
 
    Ok((p + len) * 8)
 }
diff --git a/source/marathon/shp.rs b/source/marathon/shp.rs
index a387234..d310497 100644
--- a/source/marathon/shp.rs
+++ b/source/marathon/shp.rs
@@ -103,7 +103,7 @@ pub fn read_bitmap(b: &[u8]) -> ResultS<Bitmap>
             bmp.cr.push(0);
          }
 
-         bmp.cr.extend_from_slice(ok!(b.get(p..p + end), "not enough data")?);
+         bmp.cr.extend(ok!(b.get(p..p + end), "not enough data")?);
 
          for _ in lst..pitch {
             bmp.cr.push(0);
@@ -113,8 +113,7 @@ pub fn read_bitmap(b: &[u8]) -> ResultS<Bitmap>
       }
    } else {
       // simple copy
-      bmp.cr.extend_from_slice(ok!(b.get(p..p + width * height),
-                                   "not enough data")?);
+      bmp.cr.extend(ok!(b.get(p..p + width * height), "not enough data")?);
    }
 
    Ok(bmp)