diff --git a/dom/datastore/DataStoreDB.cpp b/dom/datastore/DataStoreDB.cpp
index c9adb749b804..3bc32ad3ec25 100644
--- a/dom/datastore/DataStoreDB.cpp
+++ b/dom/datastore/DataStoreDB.cpp
@@ -117,8 +117,7 @@ DataStoreDB::HandleEvent(nsIDOMEvent* aEvent)
     return NS_OK;
   }
 
-  MOZ_ASSUME_UNREACHABLE("This should not happen");
-  return NS_OK;
+  MOZ_CRASH("This should not happen");
 }
 
 nsresult
diff --git a/dom/datastore/DataStoreRevision.cpp b/dom/datastore/DataStoreRevision.cpp
index f3754c5fc69d..c12dc7ef0aeb 100644
--- a/dom/datastore/DataStoreRevision.cpp
+++ b/dom/datastore/DataStoreRevision.cpp
@@ -53,8 +53,7 @@ DataStoreRevision::AddRevision(JSContext* aCx,
       break;
 
     default:
-      MOZ_ASSUME_UNREACHABLE("This should not happen");
-      break;
+      MOZ_CRASH("This should not happen");
   }
 
   JS::Rooted<JS::Value> value(aCx);
@@ -88,8 +87,7 @@ DataStoreRevision::HandleEvent(nsIDOMEvent* aEvent)
   }
 
   if (!type.EqualsASCII("success")) {
-    MOZ_ASSUME_UNREACHABLE("This should not happen");
-    return NS_ERROR_FAILURE;
+    MOZ_CRASH("This should not happen");
   }
 
   mRequest->RemoveEventListener(NS_LITERAL_STRING("success"), this, false);
diff --git a/dom/mobilemessage/src/DOMMobileMessageError.cpp b/dom/mobilemessage/src/DOMMobileMessageError.cpp
index 92778317f49e..025151b05cb3 100644
--- a/dom/mobilemessage/src/DOMMobileMessageError.cpp
+++ b/dom/mobilemessage/src/DOMMobileMessageError.cpp
@@ -61,7 +61,7 @@ DOMMobileMessageError::GetData(OwningMozSmsMessageOrMozMmsMessage& aRetVal) cons
     return;
   }
 
-  MOZ_ASSUME_UNREACHABLE("Bad object with invalid mSms and mMms.");
+  MOZ_CRASH("Bad object with invalid mSms and mMms.");
 }
 
 JSObject*
diff --git a/dom/telephony/TelephonyCallId.cpp b/dom/telephony/TelephonyCallId.cpp
index 677420074412..1c75f77c2878 100644
--- a/dom/telephony/TelephonyCallId.cpp
+++ b/dom/telephony/TelephonyCallId.cpp
@@ -45,7 +45,7 @@ TelephonyCallId::GetPresentationStr(uint16_t aPresentation) const
     case nsITelephonyService::CALL_PRESENTATION_PAYPHONE:
       return CallIdPresentation::Payphone;
     default:
-      MOZ_ASSUME_UNREACHABLE("Bad presentation!");
+      MOZ_CRASH("Bad presentation!");
   }
 }
 
diff --git a/dom/wifi/WifiHotspotUtils.h b/dom/wifi/WifiHotspotUtils.h
index 320f93b925c4..8f77c430fa7c 100644
--- a/dom/wifi/WifiHotspotUtils.h
+++ b/dom/wifi/WifiHotspotUtils.h
@@ -38,7 +38,7 @@ private:
 #define USE_DLFUNC(name)                                                      \
   FUNC##name name = (FUNC##name) dlsym(GetSharedLibrary(), #name);            \
   if (!name) {                                                                \
-    MOZ_ASSUME_UNREACHABLE("Symbol not found in shared library : " #name);    \
+    MOZ_CRASH("Symbol not found in shared library : " #name);                 \
   }
 
 #endif // WifiHotspotUtils_h