diff --git a/js/public/CharacterEncoding.h b/js/public/CharacterEncoding.h
index 47638161c54..41d7d1e9f4f 100644
--- a/js/public/CharacterEncoding.h
+++ b/js/public/CharacterEncoding.h
@@ -176,7 +176,7 @@ LossyTwoByteCharsToNewLatin1CharsZ(js::ExclusiveContext* cx,
 
 template <typename CharT>
 extern UTF8CharsZ
-CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx, const mozilla::Range<const CharT> chars);
+CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx, const mozilla::Range<CharT> chars);
 
 uint32_t
 Utf8ToOneUcs4Char(const uint8_t* utf8Buffer, int utf8Length);
diff --git a/js/src/vm/CharacterEncoding.cpp b/js/src/vm/CharacterEncoding.cpp
index cb7bb8ad86f..f8462f3a5b7 100644
--- a/js/src/vm/CharacterEncoding.cpp
+++ b/js/src/vm/CharacterEncoding.cpp
@@ -134,7 +134,7 @@ JS::DeflateStringToUTF8Buffer(JSFlatString* src, mozilla::RangedPtr<char> dst)
 
 template <typename CharT>
 UTF8CharsZ
-JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx, const mozilla::Range<const CharT> chars)
+JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx, const mozilla::Range<CharT> chars)
 {
     /* Get required buffer size. */
     const CharT* str = chars.start().get();
@@ -156,6 +156,14 @@ JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx, const mozilla::Range<con
     return UTF8CharsZ(utf8, len);
 }
 
+template UTF8CharsZ
+JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx,
+                         const mozilla::Range<Latin1Char> chars);
+
+template UTF8CharsZ
+JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx,
+                         const mozilla::Range<char16_t> chars);
+
 template UTF8CharsZ
 JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx,
                          const mozilla::Range<const Latin1Char> chars);