--- a/js/src/jit/JitSpewer.h
+++ b/js/src/jit/JitSpewer.h
@@ -120,18 +120,16 @@ enum JitSpewChannel {
 class BacktrackingAllocator;
 class MDefinition;
 class MIRGenerator;
 class MIRGraph;
 class TempAllocator;
 
 // The JitSpewer is only available on debug builds.
 // None of the global functions have effect on non-debug builds.
-static const int NULL_ID = -1;
-
 #ifdef JS_JITSPEW
 
 // Class made to hold the MIR and LIR graphs of an Wasm / Ion compilation.
 class GraphSpewer
 {
   private:
     MIRGraph* graph_;
     LSprinter c1Printer_;