diff --git a/layout/svg/nsSVGEffects.cpp b/layout/svg/nsSVGEffects.cpp
index d306333629ba..6a931f62498b 100644
--- a/layout/svg/nsSVGEffects.cpp
+++ b/layout/svg/nsSVGEffects.cpp
@@ -672,24 +672,6 @@ nsSVGEffects::EffectProperties::HasNoOrValidEffects()
   return HasNoOrValidClipPath() && HasNoOrValidMask() && HasNoOrValidFilter();
 }
 
-bool
-nsSVGEffects::EffectProperties::MightHaveNoneSVGMask() const
-{
-  if (!mMask) {
-    return false;
-  }
-
-  const nsTArray<RefPtr<nsSVGPaintingProperty>>& props = mMask->GetProps();
-  for (size_t i = 0; i < props.Length(); i++) {
-    if (!props[i] ||
-        !props[i]->GetReferencedFrame(nsGkAtoms::svgMaskFrame, nullptr)) {
-      return true;
-    }
-  }
-
-  return false;
-}
-
 bool
 nsSVGEffects::EffectProperties::HasNoOrValidClipPath()
 {
diff --git a/layout/svg/nsSVGEffects.h b/layout/svg/nsSVGEffects.h
index f8c26afc5ff8..0ff9b9734969 100644
--- a/layout/svg/nsSVGEffects.h
+++ b/layout/svg/nsSVGEffects.h
@@ -483,8 +483,6 @@ public:
      */
     nsTArray<nsSVGMaskFrame*> GetMaskFrames();
 
-    bool MightHaveNoneSVGMask() const;
-
     /*
      * @return true if all effects we have are valid or we have no effect
      * at all.