diff --git a/jspubtd.h b/jspubtd.h
index 97de470db..1507b6b6b 100644
--- a/jspubtd.h
+++ b/jspubtd.h
@@ -51,6 +51,11 @@ enum JSType {
 enum JSProtoKey {
 #define PROTOKEY_AND_INITIALIZER(name, clasp) JSProto_##name,
   JS_FOR_EACH_PROTOTYPE(PROTOKEY_AND_INITIALIZER)
+// Workaround MSVC's __VA_ARGS__ quirk, until bug 1768634 is solved
+// https://bugzilla.mozilla.org/show_bug.cgi?id=1768634
+#ifdef _MSC_VER
+  ,
+#endif
 #undef PROTOKEY_AND_INITIALIZER
       JSProto_LIMIT
 };

diff --git a/mozilla/Result.h b/mozilla/Result.h
index cc4f87826..0e763a300 100644
--- a/mozilla/Result.h
+++ b/mozilla/Result.h
@@ -212,10 +212,16 @@ using UnsignedIntType = std::conditional_t<
  */
 template <typename V, typename E>
 class ResultImplementation<V, E, PackingStrategy::LowBitTagIsError> {
+// These assertions fail with MSVC 14.1. Similar bugs:
+// https://bugzilla.mozilla.org/show_bug.cgi?id=1778246
+// https://bugzilla.mozilla.org/show_bug.cgi?id=1778247
+// TODO: test with recent MSVC before reporting a bug
+#ifndef _MSC_VER
   static_assert(std::is_trivially_copyable_v<V> &&
                 std::is_trivially_destructible_v<V>);
   static_assert(std::is_trivially_copyable_v<E> &&
                 std::is_trivially_destructible_v<E>);
+#endif
 
   static constexpr size_t kRequiredSize = std::max(sizeof(V), sizeof(E));