diff --git a/dom/json/nsJSON.cpp b/dom/json/nsJSON.cpp
index 790da1298c8d..86f68106866b 100644
--- a/dom/json/nsJSON.cpp
+++ b/dom/json/nsJSON.cpp
@@ -536,7 +536,7 @@ nsJSONListener::OnStopRequest(nsIRequest *aRequest, nsISupports *aContext,
 
   JS::ConstTwoByteChars chars(reinterpret_cast<const char16_t*>(mBufferedChars.Elements()),
                               mBufferedChars.Length());
-  bool ok = JS_ParseJSONWithReviver(mCx, chars.get(),
+  bool ok = JS_ParseJSONWithReviver(mCx, chars.start().get(),
                                       uint32_t(mBufferedChars.Length()),
                                       reviver, &value);
 
diff --git a/js/public/CharacterEncoding.h b/js/public/CharacterEncoding.h
index 666573211211..397a5aaad582 100644
--- a/js/public/CharacterEncoding.h
+++ b/js/public/CharacterEncoding.h
@@ -151,17 +151,13 @@ typedef mozilla::RangedPtr<const char16_t> ConstCharPtr;
 /*
  * Like TwoByteChars, but the chars are const.
  */
-class ConstTwoByteChars : public mozilla::RangedPtr<const char16_t>
+class ConstTwoByteChars : public mozilla::Range<const char16_t>
 {
-  public:
-    ConstTwoByteChars(const ConstTwoByteChars &s) : ConstCharPtr(s) {}
-    MOZ_IMPLICIT ConstTwoByteChars(const mozilla::RangedPtr<const char16_t> &s) : ConstCharPtr(s) {}
-    ConstTwoByteChars(const char16_t *s, size_t len) : ConstCharPtr(s, len) {}
-    ConstTwoByteChars(const char16_t *pos, const char16_t *start, size_t len)
-      : ConstCharPtr(pos, start, len)
-    {}
+    typedef mozilla::Range<const char16_t> Base;
 
-    using ConstCharPtr::operator=;
+  public:
+    ConstTwoByteChars() : Base() {}
+    ConstTwoByteChars(const char16_t *aChars, size_t aLength) : Base(aChars, aLength) {}
 };
 
 /*
diff --git a/js/src/jsfun.cpp b/js/src/jsfun.cpp
index 3d3b4bd50b02..f99d19b2af46 100644
--- a/js/src/jsfun.cpp
+++ b/js/src/jsfun.cpp
@@ -1820,7 +1820,7 @@ FunctionConstructor(JSContext *cx, unsigned argc, Value *vp, GeneratorKind gener
          * here (duplicate argument names, etc.) will be detected when we
          * compile the function body.
          */
-        TokenStream ts(cx, options, collected_args.get(), args_length,
+        TokenStream ts(cx, options, collected_args.start().get(), args_length,
                        /* strictModeGetter = */ nullptr);
         bool yieldIsValidName = ts.versionNumber() < JSVERSION_1_7 && !isStarGenerator;