diff --git a/src/utf16.rs b/src/utf16.rs
index 4350108..3b46814 100644
--- a/src/utf16.rs
+++ b/src/utf16.rs
@@ -98,7 +98,7 @@ fn encode_code_point(unicode_cp: u32) -> Vec<u16> {
 /// # Panics
 /// * If the index `i` is out of bounds.
 /// * If the UTF-16 code point is invalid.
-fn decode_symbol(utf16_cp: &Vec<u16>, i: usize) -> Option<(u32, usize)> {
+fn decode_symbol(utf16_cp: &[u16], i: usize) -> Option<(u32, usize)> {
     if i > utf16_cp.len() {
         panic!("Index out of bounds");
     }
diff --git a/src/utf8.rs b/src/utf8.rs
index 10ae1cc..f46326f 100644
--- a/src/utf8.rs
+++ b/src/utf8.rs
@@ -148,7 +148,7 @@ fn encode_code_point(unicode_cp: u32) -> Vec<u8> {
 /// # Panics
 /// * If the index `i` is out of bounds.
 /// * If the byte at index `i` is not a continuation byte.
-fn read_next_byte(byte_vec: &Vec<u8>, i: usize) -> u32 {
+fn read_next_byte(byte_vec: &[u8], i: usize) -> u32 {
     if i >= byte_vec.len() {
         panic!("Index out of bounds");
     }