diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -186,32 +186,33 @@
       return import(*From);
     }
 
-    template <class T>
-    Expected<std::tuple<T>>
-    importSeq(const T &From) {
-      Expected<T> ToOrErr = import(From);
-      if (!ToOrErr)
-        return ToOrErr.takeError();
-      return std::make_tuple<T>(std::move(*ToOrErr));
+    // Helper for error management in importSeq.
+    template <typename T> T checkImport(Error &Err, const T &From) {
+      // Don't attempt to import nodes if we hit an error earlier.
+      if (Err)
+        return T{};
+      Expected<T> MaybeVal = import(From);
+      if (!MaybeVal) {
+        Err = MaybeVal.takeError();
+        return T{};
+      }
+      return *MaybeVal;
     }
 
     // Import multiple objects with a single function call.
     // This should work for every type for which a variant of `import` exists.
     // The arguments are processed from left to right and import is stopped on
     // first error.
-    template <class THead, class... TTail>
-    Expected<std::tuple<THead, TTail...>>
-    importSeq(const THead &FromHead, const TTail &...FromTail) {
-      Expected<std::tuple<THead>> ToHeadOrErr = importSeq(FromHead);
-      if (!ToHeadOrErr)
-        return ToHeadOrErr.takeError();
-      Expected<std::tuple<TTail...>> ToTailOrErr = importSeq(FromTail...);
-      if (!ToTailOrErr)
-        return ToTailOrErr.takeError();
-      return std::tuple_cat(*ToHeadOrErr, *ToTailOrErr);
+    template <class... Args>
+    Expected<std::tuple<Args...>> importSeq(const Args &... args) {
+      Error E = Error::success();
+      std::tuple<Args...> Res{checkImport(E, args)...};
+      if (E)
+        return std::move(E);
+      return std::move(Res);
     }
 
-// Wrapper for an overload set.
+    // Wrapper for an overload set.
     template <typename ToDeclT> struct CallOverloadedCreateFun {
       template <typename... Args>
       auto operator()(Args &&... args)
diff --git a/llvm/include/llvm/Support/Compiler.h b/llvm/include/llvm/Support/Compiler.h
--- a/llvm/include/llvm/Support/Compiler.h
+++ b/llvm/include/llvm/Support/Compiler.h
@@ -24,13 +24,6 @@
 
 #if defined(_MSC_VER)
 #include <sal.h>
-
-#if _MSC_VER == 1924 && !defined(__clang__)
-// See https://developercommunity.visualstudio.com/content/problem/845933/miscompile-boolean-condition-deduced-to-be-always.html
-// and thread "[llvm-dev] Longstanding failing tests - clang-tidy, MachO, Polly"
-// on llvm-dev Jan 21-23 2020.
-#error "MSVC 19.24 (Visual Studio 2019 version 16.4) is known to miscompile LLVM. Please upgrade to version 16.5+ or use clang-cl."
-#endif
 #endif
 
 #ifndef __has_feature