diff --git a/js/src/jsatom.cpp b/js/src/jsatom.cpp
index 17ee99637c8..b2024e6e243 100644
--- a/js/src/jsatom.cpp
+++ b/js/src/jsatom.cpp
@@ -262,7 +262,7 @@ AtomizeAndTakeOwnership(JSContext *cx, const jschar *tbchars, size_t length,
 
     AutoEnterAtomsCompartment ac(cx);
 
-    RawFlatString flat = js_NewString<CanGC>(cx, const_cast<jschar*>(tbchars), length);
+    JSFlatString *flat = js_NewString<CanGC>(cx, const_cast<jschar*>(tbchars), length);
     if (!flat) {
         js_free((void*)tbchars);
         return NULL;
@@ -306,7 +306,7 @@ AtomizeAndCopyChars(JSContext *cx, const jschar *tbchars, size_t length, InternB
 
     AutoEnterAtomsCompartment ac(cx);
 
-    RawFlatString flat = js_NewStringCopyN<allowGC>(cx, tbchars, length);
+    JSFlatString *flat = js_NewStringCopyN<allowGC>(cx, tbchars, length);
     if (!flat)
         return NULL;
 
diff --git a/js/src/jsonparser.cpp b/js/src/jsonparser.cpp
index 8eae90b6b81..f3c6585bedd 100644
--- a/js/src/jsonparser.cpp
+++ b/js/src/jsonparser.cpp
@@ -122,9 +122,9 @@ JSONParser::readString()
 
         jschar c = *current++;
         if (c == '"') {
-            RawFlatString str = (ST == JSONParser::PropertyName)
-                                 ? buffer.finishAtom()
-                                 : buffer.finishString();
+            JSFlatString *str = (ST == JSONParser::PropertyName)
+                                ? buffer.finishAtom()
+                                : buffer.finishString();
             if (!str)
                 return token(OOM);
             return stringToken(str);
diff --git a/js/src/vm/String.h b/js/src/vm/String.h
index 41285c5899b..b3e1592c3f7 100644
--- a/js/src/vm/String.h
+++ b/js/src/vm/String.h
@@ -30,7 +30,6 @@ ForwardDeclareJS(LinearString);
 class JSStableString;
 ForwardDeclareJS(InlineString);
 class JSRope;
-ForwardDeclareJS(FlatString);
 
 namespace js {
 
diff --git a/js/src/vm/StringBuffer.cpp b/js/src/vm/StringBuffer.cpp
index d2bc3e53f1e..c4e86dbad28 100644
--- a/js/src/vm/StringBuffer.cpp
+++ b/js/src/vm/StringBuffer.cpp
@@ -38,7 +38,7 @@ StringBuffer::extractWellSized()
     return buf;
 }
 
-RawFlatString
+JSFlatString *
 StringBuffer::finishString()
 {
     JSContext *cx = context();
diff --git a/js/src/vm/StringBuffer.h b/js/src/vm/StringBuffer.h
index a80c5a7a705..44c55e0eae6 100644
--- a/js/src/vm/StringBuffer.h
+++ b/js/src/vm/StringBuffer.h
@@ -14,8 +14,6 @@
 
 #include "js/Vector.h"
 
-ForwardDeclareJS(FlatString);
-
 namespace js {
 
 /*
@@ -88,7 +86,7 @@ class StringBuffer
      * Creates a string from the characters in this buffer, then (regardless
      * whether string creation succeeded or failed) empties the buffer.
      */
-    js::RawFlatString finishString();
+    JSFlatString *finishString();
 
     /* Identical to finishString() except that an atom is created. */
     JSAtom *finishAtom();