diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index b8240d1..4480b0f 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -4372,7 +4372,13 @@
   llvm::FoldingSetNodeID ID;
   PackExpansionType::Profile(ID, Pattern, NumExpansions);
 
-  assert(Pattern->containsUnexpandedParameterPack() &&
+  // A deduced type can deduce to a pack, eg
+  //   auto ...x = some_pack;
+  // That declaration isn't (yet) valid, but is created as part of building an
+  // init-capture pack:
+  //   [...x = some_pack] {}
+  assert((Pattern->containsUnexpandedParameterPack() ||
+          Pattern->getContainedDeducedType()) &&
          "Pack expansions must expand one or more parameter packs");
   void *InsertPos = nullptr;
   PackExpansionType *T
@@ -4872,19 +4878,20 @@
 /// deduced to the given type, or to the canonical undeduced 'auto' type, or the
 /// canonical deduced-but-dependent 'auto' type.
 QualType ASTContext::getAutoType(QualType DeducedType, AutoTypeKeyword Keyword,
-                                 bool IsDependent) const {
+                                 bool IsDependent, bool IsPack) const {
+  assert((!IsPack || IsDependent) && "only use IsPack for a dependent pack");
   if (DeducedType.isNull() && Keyword == AutoTypeKeyword::Auto && !IsDependent)
     return getAutoDeductType();
 
   // Look in the folding set for an existing type.
   void *InsertPos = nullptr;
   llvm::FoldingSetNodeID ID;
-  AutoType::Profile(ID, DeducedType, Keyword, IsDependent);
+  AutoType::Profile(ID, DeducedType, Keyword, IsDependent, IsPack);
   if (AutoType *AT = AutoTypes.FindNodeOrInsertPos(ID, InsertPos))
     return QualType(AT, 0);
 
   auto *AT = new (*this, TypeAlignment)
-      AutoType(DeducedType, Keyword, IsDependent);
+      AutoType(DeducedType, Keyword, IsDependent, IsPack);
   Types.push_back(AT);
   if (InsertPos)
     AutoTypes.InsertNode(AT, InsertPos);
@@ -4946,7 +4953,7 @@
   if (AutoDeductTy.isNull())
     AutoDeductTy = QualType(
       new (*this, TypeAlignment) AutoType(QualType(), AutoTypeKeyword::Auto,
-                                          /*dependent*/false),
+                                          /*dependent*/false, /*pack*/false),
       0);
   return AutoDeductTy;
 }