diff --git a/lib/AST/ExternalASTMerger.cpp b/lib/AST/ExternalASTMerger.cpp
index 8849cfc..2761eb4 100644
--- a/lib/AST/ExternalASTMerger.cpp
+++ b/lib/AST/ExternalASTMerger.cpp
@@ -89,21 +89,25 @@
   }
 }
 
-template <typename CallbackType>
 void ForEachMatchingDC(
     const DeclContext *DC,
     llvm::ArrayRef<ExternalASTMerger::ImporterPair> Importers,
-    CallbackType Callback) {
+    std::function<void(const ExternalASTMerger::ImporterPair &IP,
+                       Source<const DeclContext *> SourceDC)>
+        Callback) {
   for (const ExternalASTMerger::ImporterPair &IP : Importers) {
-    Source<TranslationUnitDecl *> SourceTU =
-        IP.Forward->getFromContext().getTranslationUnitDecl();
-    if (auto SourceDC = LookupSameContext(SourceTU, DC, *IP.Reverse))
+    Source<TranslationUnitDecl *> SourceTU(
+        IP.Forward->getFromContext().getTranslationUnitDecl());
+    Source<const DeclContext *> SourceDC =
+        LookupSameContext(SourceTU, DC, *IP.Reverse);
+    if (SourceDC.get()) {
       Callback(IP, SourceDC);
+    }
   }
 }
 
 bool HasDeclOfSameType(llvm::ArrayRef<Candidate> Decls, const Candidate &C) {
-  return llvm::any_of(Decls, [&](const Candidate &D) {
+  return std::any_of(Decls.begin(), Decls.end(), [&C](const Candidate &D) {
     return C.first.get()->getKind() == D.first.get()->getKind();
   });
 }
@@ -135,15 +139,15 @@
     }
   };
 
-  ForEachMatchingDC(
-      DC, Importers,
-      [&](const ImporterPair &IP, Source<const DeclContext *> SourceDC) {
-        DeclarationName FromName = IP.Reverse->Import(Name);
-        DeclContextLookupResult Result = SourceDC.get()->lookup(FromName);
-        for (NamedDecl *FromD : Result) {
-          FilterFoundDecl(std::make_pair(FromD, IP.Forward.get()));
-        }
-      });
+  ForEachMatchingDC(DC, Importers, [Name, &FilterFoundDecl](
+                                       const ImporterPair &IP,
+                                       Source<const DeclContext *> SourceDC) {
+    DeclarationName FromName = IP.Reverse->Import(Name);
+    DeclContextLookupResult Result = SourceDC.get()->lookup(FromName);
+    for (NamedDecl *FromD : Result) {
+      FilterFoundDecl(std::make_pair(FromD, IP.Forward.get()));
+    }
+  });
 
   llvm::ArrayRef<Candidate> DeclsToReport =
       CompleteDecls.empty() ? ForwardDecls : CompleteDecls;
@@ -166,8 +170,8 @@
     const DeclContext *DC, llvm::function_ref<bool(Decl::Kind)> IsKindWeWant,
     SmallVectorImpl<Decl *> &Result) {
   ForEachMatchingDC(
-      DC, Importers,
-      [&](const ImporterPair &IP, Source<const DeclContext *> SourceDC) {
+      DC, Importers, [DC, IsKindWeWant](const ImporterPair &IP,
+                                        Source<const DeclContext *> SourceDC) {
         for (const Decl *SourceDecl : SourceDC.get()->decls()) {
           if (IsKindWeWant(SourceDecl->getKind())) {
             Decl *ImportedDecl =