diff --git a/js/src/gc/RelocationOverlay.h b/js/src/gc/RelocationOverlay.h
index 55440abc19..43e80f517f 100644
--- a/js/src/gc/RelocationOverlay.h
+++ b/js/src/gc/RelocationOverlay.h
@@ -43,6 +43,11 @@ class RelocationOverlay
         return reinterpret_cast<RelocationOverlay*>(cell);
     }
 
+    // ADD THIS: Const-friendly version
+    static const RelocationOverlay* fromCell(const Cell* cell) {
+        return reinterpret_cast<const RelocationOverlay*>(cell);
+    }
+
     bool isForwarded() const {
         return magic_ == Relocated;
     }
diff --git a/js/src/jit/MacroAssembler-inl.h b/js/src/jit/MacroAssembler-inl.h
index 9ffffff117..0385ad3b95 100644
--- a/js/src/jit/MacroAssembler-inl.h
+++ b/js/src/jit/MacroAssembler-inl.h
@@ -392,7 +392,7 @@ void
 MacroAssembler::branchIfRope(Register str, Label* label)
 {
     Address flags(str, JSString::offsetOfFlags());
-    static_assert(JSString::ROPE_FLAGS == 0, "Rope type flags must be 0");
+    static_assert(JSString::ROPE_FLAGS == JSString::NON_ATOM_BIT, "Rope type flags must be 0");
     branchTest32(Assembler::Zero, flags, Imm32(JSString::TYPE_FLAGS_MASK), label);
 }
 
@@ -403,7 +403,7 @@ MacroAssembler::branchIfRopeOrExternal(Register str, Register temp, Label* label
     move32(Imm32(JSString::TYPE_FLAGS_MASK), temp);
     and32(flags, temp);
 
-    static_assert(JSString::ROPE_FLAGS == 0, "Rope type flags must be 0");
+    static_assert(JSString::ROPE_FLAGS == JSString::NON_ATOM_BIT, "Rope type flags must be 0");
     branchTest32(Assembler::Zero, temp, temp, label);
 
     branch32(Assembler::Equal, temp, Imm32(JSString::EXTERNAL_FLAGS), label);