diff --git a/dom/cache/CacheOpParent.cpp b/dom/cache/CacheOpParent.cpp
index a03030e5201..5e658302ca7 100644
--- a/dom/cache/CacheOpParent.cpp
+++ b/dom/cache/CacheOpParent.cpp
@@ -195,7 +195,7 @@ CacheOpParent::OnOpComplete(ErrorResult&& aRv, const CacheOpResult& aResult,
   // void_t() to ensure that we don't leak actors on the child side.
   if (aRv.Failed()) {
     unused << Send__delete__(this, aRv, void_t());
-    aRv.ClearMessage(); // This may contain a TypeError.
+    aRv.SuppressException(); // We serialiazed it, as best we could.
     return;
   }
 
diff --git a/dom/cache/DBSchema.cpp b/dom/cache/DBSchema.cpp
index 902890f5836..b75bc0ebe01 100644
--- a/dom/cache/DBSchema.cpp
+++ b/dom/cache/DBSchema.cpp
@@ -983,14 +983,14 @@ MatchByVaryHeader(mozIStorageConnection* aConn,
       nsAutoCString queryValue;
       queryHeaders->Get(header, queryValue, errorResult);
       if (errorResult.Failed()) {
-        errorResult.ClearMessage();
+        errorResult.SuppressException();
         MOZ_ASSERT(queryValue.IsEmpty());
       }
 
       nsAutoCString cachedValue;
       cachedHeaders->Get(header, cachedValue, errorResult);
       if (errorResult.Failed()) {
-        errorResult.ClearMessage();
+        errorResult.SuppressException();
         MOZ_ASSERT(cachedValue.IsEmpty());
       }
 
diff --git a/dom/cache/FetchPut.cpp b/dom/cache/FetchPut.cpp
index 78f1ae926b8..0e03589e9f9 100644
--- a/dom/cache/FetchPut.cpp
+++ b/dom/cache/FetchPut.cpp
@@ -160,7 +160,8 @@ FetchPut::~FetchPut()
   MOZ_ASSERT(!mListener);
   mManager->RemoveListener(this);
   mManager->ReleaseCacheId(mCacheId);
-  mResult.ClearMessage(); // This may contain a TypeError.
+  mResult.SuppressException(); // XXXbz should we really be ending up here with
+                               // a failed mResult we never reported to anyone?
 }
 
 nsresult
@@ -389,14 +390,14 @@ FetchPut::MatchInPutList(const CacheRequest& aRequest,
         nsAutoCString value;
         requestHeaders->Get(header, value, headerRv);
         if (NS_WARN_IF(headerRv.Failed())) {
-          headerRv.ClearMessage();
+          headerRv.SuppressException();
           MOZ_ASSERT(value.IsEmpty());
         }
 
         nsAutoCString cachedValue;
         cachedRequestHeaders->Get(header, value, headerRv);
         if (NS_WARN_IF(headerRv.Failed())) {
-          headerRv.ClearMessage();
+          headerRv.SuppressException();
           MOZ_ASSERT(cachedValue.IsEmpty());
         }
 
diff --git a/dom/fetch/FetchDriver.cpp b/dom/fetch/FetchDriver.cpp
index 99c55c54d76..808fa747b40 100644
--- a/dom/fetch/FetchDriver.cpp
+++ b/dom/fetch/FetchDriver.cpp
@@ -634,7 +634,7 @@ public:
       NS_WARNING(nsPrintfCString("Fetch ignoring illegal header - '%s': '%s'",
                                  PromiseFlatCString(aHeader).get(),
                                  PromiseFlatCString(aValue).get()).get());
-      result.ClearMessage();
+      result.SuppressException();
     }
     return NS_OK;
   }