--- a/js/src/jit/MIRGenerator.h
+++ b/js/src/jit/MIRGenerator.h
@@ -165,18 +165,16 @@ class MIRGenerator
 
   public:
     CompileCompartment* compartment;
 
   protected:
     const CompileInfo* info_;
     const OptimizationInfo* optimizationInfo_;
     TempAllocator* alloc_;
-    JSFunction* fun_;
-    uint32_t nslots_;
     MIRGraph* graph_;
     AbortReason abortReason_;
     bool shouldForceAbort_; // Force AbortReason_Disable
     ObjectGroupVector abortedPreliminaryGroups_;
     bool error_;
     mozilla::Atomic<bool, mozilla::Relaxed>* pauseBuild_;
     mozilla::Atomic<bool, mozilla::Relaxed> cancelBuild_;