diff --git a/include/swift/AST/LazyResolver.h b/include/swift/AST/LazyResolver.h
index b6cabd44b2a..afd90352852 100644
--- a/include/swift/AST/LazyResolver.h
+++ b/include/swift/AST/LazyResolver.h
@@ -103,6 +103,11 @@ public:
   virtual void
   loadRequirementSignature(const ProtocolDecl *proto, uint64_t contextData,
                            SmallVectorImpl<Requirement> &requirements) = 0;
+
+  /// Returns the replaced decl for a given @_dynamicReplacement(for:) attribute.
+  virtual ValueDecl *
+  loadDynamicallyReplacedFunctionDecl(const DynamicReplacementAttr *DRA,
+                                      uint64_t contextData) = 0;
 };
 
 /// A class that can lazily load conformances from a serialized format.
diff --git a/lib/ClangImporter/ImporterImpl.h b/lib/ClangImporter/ImporterImpl.h
index 7dba7c806ea..86a51564f73 100644
--- a/lib/ClangImporter/ImporterImpl.h
+++ b/lib/ClangImporter/ImporterImpl.h
@@ -1230,6 +1230,12 @@ public:
     llvm_unreachable("unimplemented for ClangImporter");
   }
 
+  ValueDecl *
+  loadDynamicallyReplacedFunctionDecl(const DynamicReplacementAttr *DRA,
+                                      uint64_t contextData) override {
+    llvm_unreachable("unimplemented for ClangImporter");
+  }
+
   void loadRequirementSignature(const ProtocolDecl *decl, uint64_t contextData,
                                 SmallVectorImpl<Requirement> &reqs) override {
     llvm_unreachable("unimplemented for ClangImporter");
diff --git a/lib/Serialization/Deserialization.cpp b/lib/Serialization/Deserialization.cpp
index cc5aeab878d..83d6bea4eb7 100644
--- a/lib/Serialization/Deserialization.cpp
+++ b/lib/Serialization/Deserialization.cpp
@@ -5457,6 +5457,11 @@ ModuleFile::loadAssociatedTypeDefault(const swift::AssociatedTypeDecl *ATD,
   return getType(contextData);
 }
 
+ValueDecl *ModuleFile::loadDynamicallyReplacedFunctionDecl(
+    const DynamicReplacementAttr *DRA, uint64_t contextData) {
+  return cast<ValueDecl>(getDecl(contextData));
+}
+
 void ModuleFile::finishNormalConformance(NormalProtocolConformance *conformance,
                                          uint64_t contextData) {
   using namespace decls_block;
diff --git a/lib/Serialization/ModuleFile.h b/lib/Serialization/ModuleFile.h
index 32623ed1b17..bc111059907 100644
--- a/lib/Serialization/ModuleFile.h
+++ b/lib/Serialization/ModuleFile.h
@@ -839,6 +839,10 @@ public:
   virtual Type loadAssociatedTypeDefault(const AssociatedTypeDecl *ATD,
                                          uint64_t contextData) override;
 
+  virtual ValueDecl *
+  loadDynamicallyReplacedFunctionDecl(const DynamicReplacementAttr *DRA,
+                                      uint64_t contextData) override;
+
   virtual void finishNormalConformance(NormalProtocolConformance *conformance,
                                        uint64_t contextData) override;