--- a/dom/canvas/WebGLFramebuffer.cpp
+++ b/dom/canvas/WebGLFramebuffer.cpp
@@ -1075,25 +1075,25 @@ WebGLFramebuffer::ResolvedData::Resolved
     ////
 
     const auto fnColor = [&](const WebGLFBAttachPoint& attach,
                              decltype(drawSet)* const out_destSet)
     {
         if (!fnCommon(attach))
             return;
 
-        out_destSet->insert(attach);
+        out_destSet->insert(WebGLFBAttachPoint::Ordered(attach));
     };
 
     const auto fnDepthStencil = [&](const WebGLFBAttachPoint& attach) {
         if (!fnCommon(attach))
             return;
 
-        drawSet.insert(attach);
-        readSet.insert(attach);
+        drawSet.insert(WebGLFBAttachPoint::Ordered(attach));
+        readSet.insert(WebGLFBAttachPoint::Ordered(attach));
     };
 
     ////
 
     fnDepthStencil(parent.mDepthAttachment);
     fnDepthStencil(parent.mStencilAttachment);
     fnDepthStencil(parent.mDepthStencilAttachment);
 

--- a/dom/canvas/WebGLFramebuffer.h
+++ b/dom/canvas/WebGLFramebuffer.h
@@ -102,17 +102,17 @@ public:
 
     void OnBackingStoreRespecified() const;
 
     ////
 
     struct Ordered {
         const WebGLFBAttachPoint& mRef;
 
-        Ordered(const WebGLFBAttachPoint& ref)
+        explicit Ordered(const WebGLFBAttachPoint& ref)
             : mRef(ref)
         { }
 
         bool operator<(const Ordered& other) const {
             MOZ_ASSERT(mRef.IsDefined() && other.mRef.IsDefined());
 
 #define ORDER_BY(X) if (X != other.X) return X < other.X;
 
@@ -177,17 +177,17 @@ protected:
         const WebGLFBAttachPoint* depthBuffer;
         const WebGLFBAttachPoint* stencilBuffer;
 
         // IsFeedback
         std::vector<const WebGLFBAttachPoint*> texDrawBuffers; // Non-null
         std::set<WebGLFBAttachPoint::Ordered> drawSet;
         std::set<WebGLFBAttachPoint::Ordered> readSet;
 
-        ResolvedData(const WebGLFramebuffer& parent);
+        explicit ResolvedData(const WebGLFramebuffer& parent);
     };
 
     UniquePtr<const ResolvedData> mResolvedCompleteData;
 
     ////
 
 public:
     NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(WebGLFramebuffer)