diff --git a/clang/include/clang/AST/DeclBase.h b/clang/include/clang/AST/DeclBase.h
index 5d5d45267a58..a4a52e2a78df 100644
--- a/clang/include/clang/AST/DeclBase.h
+++ b/clang/include/clang/AST/DeclBase.h
@@ -1412,6 +1412,9 @@ public:
 
   /// @brief Removes a declaration from this context.
   void removeDecl(Decl *D);
+    
+  /// @brief Checks whether a declaration is in this context.
+  bool containsDecl(Decl *D) const;
 
   /// lookup_iterator - An iterator that provides access to the results
   /// of looking up a name within this context.
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index c1fbdb996d37..7b7900640b2a 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -1064,6 +1064,11 @@ bool DeclContext::decls_empty() const {
   return !FirstDecl;
 }
 
+bool DeclContext::containsDecl(Decl *D) const {
+  return (D->getLexicalDeclContext() == this &&
+          (D->NextInContextAndBits.getPointer() || D == LastDecl));
+}
+
 void DeclContext::removeDecl(Decl *D) {
   assert(D->getLexicalDeclContext() == this &&
          "decl being removed from non-lexical context");