diff --git a/clang/include/clang/AST/ASTImportError.h b/clang/include/clang/AST/ASTImportError.h
new file mode 100644
--- /dev/null
+++ b/clang/include/clang/AST/ASTImportError.h
@@ -0,0 +1,50 @@
+//===- ASTImportError.h - Define errors while importing AST -----*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines the ASTImportError class which basically defines the kind
+//  of error while importing AST .
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_AST_ASTIMPORTERROR_H
+#define LLVM_CLANG_AST_ASTIMPORTERROR_H
+
+#include "llvm/Support/Error.h"
+
+namespace clang {
+
+class ImportError : public llvm::ErrorInfo<ImportError> {
+public:
+  /// \brief Kind of error when importing an AST component.
+  enum ErrorKind {
+    NameConflict,         /// Naming ambiguity (likely ODR violation).
+    UnsupportedConstruct, /// Not supported node or case.
+    Unknown               /// Other error.
+  };
+
+  ErrorKind Error;
+
+  static char ID;
+
+  ImportError() : Error(Unknown) {}
+  ImportError(const ImportError &Other) : Error(Other.Error) {}
+  ImportError &operator=(const ImportError &Other) {
+    Error = Other.Error;
+    return *this;
+  }
+  ImportError(ErrorKind Error) : Error(Error) {}
+
+  std::string toString() const;
+
+  void log(llvm::raw_ostream &OS) const override;
+  std::error_code convertToErrorCode() const override;
+};
+
+} // namespace clang
+
+#endif // LLVM_CLANG_AST_ASTIMPORTERROR_H
diff --git a/clang/include/clang/AST/ASTImporter.h b/clang/include/clang/AST/ASTImporter.h
--- a/clang/include/clang/AST/ASTImporter.h
+++ b/clang/include/clang/AST/ASTImporter.h
@@ -14,7 +14,7 @@
 #ifndef LLVM_CLANG_AST_ASTIMPORTER_H
 #define LLVM_CLANG_AST_ASTIMPORTER_H
 
-#include "clang/AST/APValue.h"
+#include "clang/AST/ASTImportError.h"
 #include "clang/AST/DeclBase.h"
 #include "clang/AST/DeclarationName.h"
 #include "clang/AST/ExprCXX.h"
@@ -29,7 +29,6 @@
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
-#include "llvm/Support/Error.h"
 #include <utility>
 
 namespace clang {
@@ -49,33 +48,6 @@
 class TranslationUnitDecl;
 class TypeSourceInfo;
 
-  class ImportError : public llvm::ErrorInfo<ImportError> {
-  public:
-    /// \brief Kind of error when importing an AST component.
-    enum ErrorKind {
-        NameConflict, /// Naming ambiguity (likely ODR violation).
-        UnsupportedConstruct, /// Not supported node or case.
-        Unknown /// Other error.
-    };
-
-    ErrorKind Error;
-
-    static char ID;
-
-    ImportError() : Error(Unknown) {}
-    ImportError(const ImportError &Other) : Error(Other.Error) {}
-    ImportError &operator=(const ImportError &Other) {
-      Error = Other.Error;
-      return *this;
-    }
-    ImportError(ErrorKind Error) : Error(Error) { }
-
-    std::string toString() const;
-
-    void log(raw_ostream &OS) const override;
-    std::error_code convertToErrorCode() const override;
-  };
-
   // \brief Returns with a list of declarations started from the canonical decl
   // then followed by subsequent decls in the translation unit.
   // This gives a canonical list for each entry in the redecl chain.
diff --git a/clang/include/clang/AST/ASTImporterSharedState.h b/clang/include/clang/AST/ASTImporterSharedState.h
--- a/clang/include/clang/AST/ASTImporterSharedState.h
+++ b/clang/include/clang/AST/ASTImporterSharedState.h
@@ -14,11 +14,10 @@
 #ifndef LLVM_CLANG_AST_ASTIMPORTERSHAREDSTATE_H
 #define LLVM_CLANG_AST_ASTIMPORTERSHAREDSTATE_H
 
+#include "clang/AST/ASTImportError.h"
 #include "clang/AST/ASTImporterLookupTable.h"
 #include "clang/AST/Decl.h"
 #include "llvm/ADT/DenseMap.h"
-// FIXME We need this because of ImportError.
-#include "clang/AST/ASTImporter.h"
 
 namespace clang {