diff --git a/js/src/gc/GCRuntime.h b/js/src/gc/GCRuntime.h
index b1b4ffcba4..872e649fa8 100644
--- a/js/src/gc/GCRuntime.h
+++ b/js/src/gc/GCRuntime.h
@@ -977,7 +977,6 @@ class GCRuntime
     void releaseRelocatedArenasWithoutUnlocking(Arena* arenaList, const AutoLockGC& lock);
     void finishCollection(JS::gcreason::Reason reason);
 
-    void validateIncrementalMarking();
     void finishMarkingValidation();
 
 #ifdef DEBUG
diff --git a/js/src/jsgc.cpp b/js/src/jsgc.cpp
index 5082d03713..6fcb72b70a 100644
--- a/js/src/jsgc.cpp
+++ b/js/src/jsgc.cpp
@@ -3885,11 +3885,6 @@ GCRuntime::markAllGrayReferences(gcstats::Phase phase)
     markGrayReferences<GCZonesIter, GCCompartmentsIter>(phase);
 }
 
-void
-GCRuntime::validateIncrementalMarking()
-{
-}
-
 void
 GCRuntime::finishMarkingValidation()
 {
@@ -4529,8 +4524,6 @@ GCRuntime::beginSweepingZoneGroup(AutoLockForExclusiveAccess& lock)
 #endif
     }
 
-    validateIncrementalMarking();
-
     FreeOp fop(rt);
     SweepAtomsTask sweepAtomsTask(rt);
     SweepCCWrappersTask sweepCCWrappersTask(rt);