diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f7b7ac8..c08d87d 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -4816,6 +4816,10 @@
 }
 
 static void checkAttributesAfterMerging(Sema &S, NamedDecl &ND) {
+  // Ensure that an auto decl is deduced otherwise the checks below might cache
+  // the wrong linkage.
+  assert(S.ParsingInitForAutoVars.count(&ND) == 0);
+
   // 'weak' only applies to declarations with external linkage.
   if (WeakAttr *Attr = ND.getAttr<WeakAttr>()) {
     if (!ND.isExternallyVisible()) {
@@ -5431,7 +5435,6 @@
   }
 
   ProcessPragmaWeak(S, NewVD);
-  checkAttributesAfterMerging(*this, *NewVD);
 
   // If this is the first declaration of an extern C variable, update
   // the map of such variables.
@@ -8892,6 +8895,8 @@
   if (!VD)
     return;
 
+  checkAttributesAfterMerging(*this, *VD);
+
   if (UsedAttr *Attr = VD->getAttr<UsedAttr>()) {
     if (!Attr->isInherited() && !VD->isThisDeclarationADefinition()) {
       Diag(Attr->getLocation(), diag::warn_attribute_ignored) << Attr;