diff --git a/clang/include/clang/Basic/DiagnosticLexKinds.td b/clang/include/clang/Basic/DiagnosticLexKinds.td
--- a/clang/include/clang/Basic/DiagnosticLexKinds.td
+++ b/clang/include/clang/Basic/DiagnosticLexKinds.td
@@ -300,6 +300,17 @@
 def pp_pragma_sysheader_in_main_file : Warning<
   "#pragma system_header ignored in main file">,
   InGroup<DiagGroup<"pragma-system-header-outside-header">>;
+
+def pp_pragma_include_instead_not_sysheader : Error<
+  "'#pragma clang include_instead' cannot be used outside of system headers">,
+  ShowInSystemHeader;
+def pp_pragma_include_instead_unexpected_token : Error<
+  "'#pragma clang include_instead' expects '%0' as its next token; got '%1' instead">,
+  ShowInSystemHeader;
+def pp_pragma_include_instead_system_reserved : Error<
+  "header '%0' is an implementation detail; #include %select{'%2'|either '%2' or '%3'|one of %2}1 instead">,
+  ShowInSystemHeader;
+
 def pp_poisoning_existing_macro : Warning<"poisoning existing macro">;
 def pp_out_of_date_dependency : Warning<
   "current file is older than dependency %0">;
diff --git a/clang/include/clang/Lex/HeaderSearch.h b/clang/include/clang/Lex/HeaderSearch.h
--- a/clang/include/clang/Lex/HeaderSearch.h
+++ b/clang/include/clang/Lex/HeaderSearch.h
@@ -20,9 +20,12 @@
 #include "clang/Lex/ModuleMap.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringMap.h"
-#include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/Support/Allocator.h"
 #include <cassert>
 #include <cstddef>
@@ -110,6 +113,14 @@
   /// of the framework.
   StringRef Framework;
 
+  /// List of aliases that this header is known as.
+  /// Most headers should only have at most one alias, but a handful
+  /// have two.
+  llvm::SetVector<llvm::SmallString<32>,
+                  llvm::SmallVector<llvm::SmallString<32>, 2>,
+                  llvm::SmallSet<llvm::SmallString<32>, 2>>
+      Aliases;
+
   HeaderFileInfo()
       : isImport(false), isPragmaOnce(false), DirInfo(SrcMgr::C_User),
         External(false), isModuleHeader(false), isCompilingModuleHeader(false),
@@ -453,6 +464,10 @@
     getFileInfo(File).DirInfo = SrcMgr::C_System;
   }
 
+  void AddFileAlias(const FileEntry *File, StringRef Alias) {
+    getFileInfo(File).Aliases.insert(Alias);
+  }
+
   /// Mark the specified file as part of a module.
   void MarkFileModuleHeader(const FileEntry *FE,
                             ModuleMap::ModuleHeaderRole Role,
diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -1953,7 +1953,8 @@
   /// This either returns the EOF token and returns true, or
   /// pops a level off the include stack and returns false, at which point the
   /// client should call lex again.
-  bool HandleEndOfFile(Token &Result, bool isEndOfMacro = false);
+  bool HandleEndOfFile(Token &Result, SourceLocation Loc,
+                       bool isEndOfMacro = false);
 
   /// Callback invoked when the current TokenLexer hits the end of its
   /// token stream.
@@ -2363,12 +2364,14 @@
 
   // Pragmas.
   void HandlePragmaDirective(PragmaIntroducer Introducer);
+  void ResolvePragmaIncludeInstead(SourceLocation Location) const;
 
 public:
   void HandlePragmaOnce(Token &OnceTok);
   void HandlePragmaMark(Token &MarkTok);
   void HandlePragmaPoison();
   void HandlePragmaSystemHeader(Token &SysHeaderTok);
+  void HandlePragmaIncludeInstead(Token &Tok);
   void HandlePragmaDependency(Token &DependencyTok);
   void HandlePragmaPushMacro(Token &Tok);
   void HandlePragmaPopMacro(Token &Tok);
diff --git a/clang/include/clang/Lex/PreprocessorLexer.h b/clang/include/clang/Lex/PreprocessorLexer.h
--- a/clang/include/clang/Lex/PreprocessorLexer.h
+++ b/clang/include/clang/Lex/PreprocessorLexer.h
@@ -14,11 +14,13 @@
 #ifndef LLVM_CLANG_LEX_PREPROCESSORLEXER_H
 #define LLVM_CLANG_LEX_PREPROCESSORLEXER_H
 
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/MultipleIncludeOpt.h"
 #include "clang/Lex/Token.h"
-#include "clang/Basic/SourceLocation.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringMap.h"
 #include <cassert>
 
 namespace clang {
@@ -74,6 +76,13 @@
   /// we are currently in.
   SmallVector<PPConditionalInfo, 4> ConditionalStack;
 
+  struct IncludeInfo {
+    const FileEntry *File;
+    SourceLocation Location;
+  };
+  // A complete history of all the files included by the current file.
+  llvm::StringMap<IncludeInfo> IncludeHistory;
+
   PreprocessorLexer() : FID() {}
   PreprocessorLexer(Preprocessor *pp, FileID fid);
   virtual ~PreprocessorLexer() = default;
@@ -175,6 +184,15 @@
     ConditionalStack.clear();
     ConditionalStack.append(CL.begin(), CL.end());
   }
+
+  void addInclude(StringRef Filename, const FileEntry &File,
+                  SourceLocation Location) {
+    IncludeHistory.insert({Filename, {&File, Location}});
+  }
+
+  const llvm::StringMap<IncludeInfo> &getIncludeHistory() const {
+    return IncludeHistory;
+  }
 };
 
 } // namespace clang
diff --git a/clang/lib/Lex/Lexer.cpp b/clang/lib/Lex/Lexer.cpp
--- a/clang/lib/Lex/Lexer.cpp
+++ b/clang/lib/Lex/Lexer.cpp
@@ -2811,11 +2811,11 @@
     ConditionalStack.pop_back();
   }
 
+  SourceLocation EndLoc = getSourceLocation(BufferEnd);
   // C99 5.1.1.2p2: If the file is non-empty and didn't end in a newline, issue
   // a pedwarn.
   if (CurPtr != BufferStart && (CurPtr[-1] != '\n' && CurPtr[-1] != '\r')) {
     DiagnosticsEngine &Diags = PP->getDiagnostics();
-    SourceLocation EndLoc = getSourceLocation(BufferEnd);
     unsigned DiagID;
 
     if (LangOpts.CPlusPlus11) {
@@ -2838,7 +2838,7 @@
   BufferPtr = CurPtr;
 
   // Finally, let the preprocessor handle this.
-  return PP->HandleEndOfFile(Result, isPragmaLexer());
+  return PP->HandleEndOfFile(Result, EndLoc, isPragmaLexer());
 }
 
 /// isNextPPTokenLParen - Return 1 if the next unexpanded token lexed from
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -2022,6 +2022,12 @@
       IsFrameworkFound, IsImportDecl, IsMapped, LookupFrom, LookupFromFile,
       LookupFilename, RelativePath, SearchPath, SuggestedModule, isAngled);
 
+  // Record the header's filename for later use.
+  if (File)
+    CurLexer->addInclude(
+        {FilenameTok.getLiteralData(), FilenameTok.getLength()},
+        File->getFileEntry(), FilenameLoc);
+
   if (usingPCHWithThroughHeader() && SkippingUntilPCHThroughHeader) {
     if (File && isPCHThroughHeader(&File->getFileEntry()))
       SkippingUntilPCHThroughHeader = false;
diff --git a/clang/lib/Lex/PPLexerChange.cpp b/clang/lib/Lex/PPLexerChange.cpp
--- a/clang/lib/Lex/PPLexerChange.cpp
+++ b/clang/lib/Lex/PPLexerChange.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Basic/FileManager.h"
+#include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/LexDiagnostic.h"
@@ -22,6 +23,7 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBufferRef.h"
 #include "llvm/Support/Path.h"
+
 using namespace clang;
 
 //===----------------------------------------------------------------------===//
@@ -299,10 +301,51 @@
   }
 }
 
+void Preprocessor::ResolvePragmaIncludeInstead(
+    const SourceLocation Location) const {
+  assert(Location.isValid());
+  if (CurLexer == nullptr)
+    return;
+
+  if (SourceMgr.isInSystemHeader(Location))
+    return;
+
+  for (const auto &Include : CurLexer->getIncludeHistory()) {
+    StringRef Filename = Include.getKey();
+    const auto &IncludeInfo = Include.getValue();
+    const HeaderFileInfo &Info = HeaderInfo.getFileInfo(IncludeInfo.File);
+
+    if (Info.Aliases.empty())
+      continue;
+
+    switch (Info.Aliases.size()) {
+    case 1:
+      Diag(IncludeInfo.Location,
+           diag::pp_pragma_include_instead_system_reserved)
+          << Filename << 0 << Info.Aliases[0];
+      continue;
+    case 2:
+      Diag(IncludeInfo.Location,
+           diag::pp_pragma_include_instead_system_reserved)
+          << Filename << 1 << Info.Aliases[0] << Info.Aliases[1];
+      continue;
+    default: {
+      std::string Aliases =
+          "{'" + llvm::join(Info.Aliases.begin(), Info.Aliases.end(), "', '") +
+          "'}";
+      Diag(IncludeInfo.Location,
+           diag::pp_pragma_include_instead_system_reserved)
+          << Filename << 2 << Aliases;
+    }
+    }
+  }
+}
+
 /// HandleEndOfFile - This callback is invoked when the lexer hits the end of
 /// the current file.  This either returns the EOF token or pops a level off
 /// the include stack and keeps going.
-bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) {
+bool Preprocessor::HandleEndOfFile(Token &Result, SourceLocation EndLoc,
+                                   bool isEndOfMacro) {
   assert(!CurTokenLexer &&
          "Ending a file when currently in a macro!");
 
@@ -372,6 +415,9 @@
     }
   }
 
+  if (EndLoc.isValid())
+    ResolvePragmaIncludeInstead(EndLoc);
+
   // Complain about reaching a true EOF within arc_cf_code_audited.
   // We don't want to complain about reaching the end of a macro
   // instantiation or a _Pragma.
@@ -560,7 +606,7 @@
     TokenLexerCache[NumCachedTokenLexers++] = std::move(CurTokenLexer);
 
   // Handle this like a #include file being popped off the stack.
-  return HandleEndOfFile(Result, true);
+  return HandleEndOfFile(Result, {}, true);
 }
 
 /// RemoveTopOfLexerStack - Pop the current lexer/macro exp off the top of the
diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
--- a/clang/lib/Lex/Pragma.cpp
+++ b/clang/lib/Lex/Pragma.cpp
@@ -13,6 +13,7 @@
 
 #include "clang/Lex/Pragma.h"
 #include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticLex.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/LLVM.h"
@@ -35,11 +36,12 @@
 #include "clang/Lex/TokenLexer.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Timer.h"
@@ -495,43 +497,90 @@
                         SrcMgr::C_System);
 }
 
-/// HandlePragmaDependency - Handle \#pragma GCC dependency "foo" blah.
-void Preprocessor::HandlePragmaDependency(Token &DependencyTok) {
+static llvm::Optional<Token> LexHeader(Preprocessor &PP,
+                                       Optional<FileEntryRef> &File,
+                                       bool SuppressIncludeNotFoundError) {
   Token FilenameTok;
-  if (LexHeaderName(FilenameTok, /*AllowConcatenation*/false))
-    return;
+  if (PP.LexHeaderName(FilenameTok, /*AllowConcatenation*/ false))
+    return llvm::None;
 
   // If the next token wasn't a header-name, diagnose the error.
   if (FilenameTok.isNot(tok::header_name)) {
-    Diag(FilenameTok.getLocation(), diag::err_pp_expects_filename);
-    return;
+    PP.Diag(FilenameTok.getLocation(), diag::err_pp_expects_filename);
+    return llvm::None;
   }
 
   // Reserve a buffer to get the spelling.
   SmallString<128> FilenameBuffer;
   bool Invalid = false;
-  StringRef Filename = getSpelling(FilenameTok, FilenameBuffer, &Invalid);
+  StringRef Filename = PP.getSpelling(FilenameTok, FilenameBuffer, &Invalid);
   if (Invalid)
-    return;
+    return llvm::None;
 
   bool isAngled =
-    GetIncludeFilenameSpelling(FilenameTok.getLocation(), Filename);
+      PP.GetIncludeFilenameSpelling(FilenameTok.getLocation(), Filename);
   // If GetIncludeFilenameSpelling set the start ptr to null, there was an
   // error.
   if (Filename.empty())
-    return;
+    return llvm::None;
 
   // Search include directories for this file.
   const DirectoryLookup *CurDir;
-  Optional<FileEntryRef> File =
-      LookupFile(FilenameTok.getLocation(), Filename, isAngled, nullptr,
-                 nullptr, CurDir, nullptr, nullptr, nullptr, nullptr, nullptr);
+  File = PP.LookupFile(FilenameTok.getLocation(), Filename, isAngled, nullptr,
+                       nullptr, CurDir, nullptr, nullptr, nullptr, nullptr,
+                       nullptr);
   if (!File) {
     if (!SuppressIncludeNotFoundError)
-      Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
+      PP.Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
+    return llvm::None;
+  }
+
+  return FilenameTok;
+}
+
+/// HandlePragmaIncludeInstead - Handle \#pragma clang include_instead(header).
+void Preprocessor::HandlePragmaIncludeInstead(Token &Tok) {
+  // Get the current file lexer we're looking at.  Ignore _Pragma 'files' etc.
+  PreprocessorLexer *TheLexer = getCurrentFileLexer();
+
+  if (!SourceMgr.isInSystemHeader(Tok.getLocation())) {
+    Diag(Tok, diag::pp_pragma_include_instead_not_sysheader);
+    return;
+  }
+
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(Tok, diag::pp_pragma_include_instead_unexpected_token)
+        << "(" << getSpelling(Tok);
+    return;
+  }
+
+  Optional<FileEntryRef> File;
+  llvm::Optional<Token> FilenameTok =
+      LexHeader(*this, File, SuppressIncludeNotFoundError);
+  if (!FilenameTok)
+    return;
+
+  Lex(Tok);
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(Tok, diag::pp_pragma_include_instead_unexpected_token)
+        << ")" << getSpelling(Tok);
     return;
   }
 
+  HeaderInfo.AddFileAlias(
+      TheLexer->getFileEntry(),
+      {FilenameTok->getLiteralData(), FilenameTok->getLength()});
+}
+
+/// HandlePragmaDependency - Handle \#pragma GCC dependency "foo" blah.
+void Preprocessor::HandlePragmaDependency(Token &DependencyTok) {
+  Optional<FileEntryRef> File;
+  llvm::Optional<Token> FilenameTok =
+      LexHeader(*this, File, SuppressIncludeNotFoundError);
+  if (!FilenameTok)
+    return;
+
   const FileEntry *CurFile = getCurrentFileLexer()->getFileEntry();
 
   // If this file is older than the file it depends on, emit a diagnostic.
@@ -547,7 +596,7 @@
     // Remove the trailing ' ' if present.
     if (!Message.empty())
       Message.erase(Message.end()-1);
-    Diag(FilenameTok, diag::pp_out_of_date_dependency) << Message;
+    Diag(*FilenameTok, diag::pp_out_of_date_dependency) << Message;
   }
 }
 
@@ -1022,6 +1071,18 @@
   }
 };
 
+/// PragmaIncludeInsteadHandler - "\#pragma clang include_instead(header)" marks
+/// the current file as non-includable if the including header is not a system
+/// header.
+struct PragmaIncludeInsteadHandler : public PragmaHandler {
+  PragmaIncludeInsteadHandler() : PragmaHandler("include_instead") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &IIToken) override {
+    PP.HandlePragmaIncludeInstead(IIToken);
+  }
+};
+
 struct PragmaDependencyHandler : public PragmaHandler {
   PragmaDependencyHandler() : PragmaHandler("dependency") {}
 
@@ -1934,6 +1995,7 @@
   // #pragma clang ...
   AddPragmaHandler("clang", new PragmaPoisonHandler());
   AddPragmaHandler("clang", new PragmaSystemHeaderHandler());
+  AddPragmaHandler("clang", new PragmaIncludeInsteadHandler());
   AddPragmaHandler("clang", new PragmaDebugHandler());
   AddPragmaHandler("clang", new PragmaDependencyHandler());
   AddPragmaHandler("clang", new PragmaDiagnosticHandler("clang"));
diff --git a/clang/test/Preprocessor/Inputs/include_instead/bad-syntax.h b/clang/test/Preprocessor/Inputs/include_instead/bad-syntax.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/bad-syntax.h
@@ -0,0 +1,7 @@
+#pragma GCC system_header
+
+#pragma clang include_instead <include_instead/public-before.h>
+// expected-error@-1{{'#pragma clang include_instead' expects '(' as its next token; got '<' instead}}
+
+#pragma clang include_instead(<include_instead/public-after.h>]
+// expected-error@-1{{'#pragma clang include_instead' expects ')' as its next token; got ']' instead}}
diff --git a/clang/test/Preprocessor/Inputs/include_instead/file-not-found.h b/clang/test/Preprocessor/Inputs/include_instead/file-not-found.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/file-not-found.h
@@ -0,0 +1,3 @@
+#pragma GCC system_header
+#pragma clang include_instead(<include_instead/does_not_exist.h>)
+// expected-error@-1{{'include_instead/does_not_exist.h' file not found}}
diff --git a/clang/test/Preprocessor/Inputs/include_instead/non-system-header.h b/clang/test/Preprocessor/Inputs/include_instead/non-system-header.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/non-system-header.h
@@ -0,0 +1,2 @@
+#pragma clang include_instead(<include_instead/public1.h>)
+// expected-error@-1{{'#pragma clang include_instead' cannot be used outside of system headers}}
diff --git a/clang/test/Preprocessor/Inputs/include_instead/private-x.h b/clang/test/Preprocessor/Inputs/include_instead/private-x.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/private-x.h
@@ -0,0 +1,4 @@
+#include <include_instead/private1.h>
+
+#pragma GCC system_header
+#pragma clang include_instead(<include_instead/public-gcc-system-header-before-includes.h>)
diff --git a/clang/test/Preprocessor/Inputs/include_instead/private1.h b/clang/test/Preprocessor/Inputs/include_instead/private1.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/private1.h
@@ -0,0 +1,2 @@
+#pragma GCC system_header
+#pragma clang include_instead(<include_instead/public-before.h>)
diff --git a/clang/test/Preprocessor/Inputs/include_instead/private2.h b/clang/test/Preprocessor/Inputs/include_instead/private2.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/private2.h
@@ -0,0 +1,4 @@
+#pragma GCC system_header
+
+#pragma clang include_instead(<include_instead/public-before.h>)
+#pragma clang include_instead("include_instead/public-after.h")
diff --git a/clang/test/Preprocessor/Inputs/include_instead/private3.h b/clang/test/Preprocessor/Inputs/include_instead/private3.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/private3.h
@@ -0,0 +1,5 @@
+#pragma GCC system_header
+
+#pragma clang include_instead(<include_instead/public-after.h>)
+#pragma clang include_instead(<include_instead/public-empty.h>)
+#pragma clang include_instead("include_instead/public-before.h")
diff --git a/clang/test/Preprocessor/Inputs/include_instead/public-after.h b/clang/test/Preprocessor/Inputs/include_instead/public-after.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/public-after.h
@@ -0,0 +1,2 @@
+#include <include_instead/private2.h>
+#pragma GCC system_header
diff --git a/clang/test/Preprocessor/Inputs/include_instead/public-before.h b/clang/test/Preprocessor/Inputs/include_instead/public-before.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/public-before.h
@@ -0,0 +1,5 @@
+#pragma GCC system_header
+
+#include <include_instead/private1.h> // no warning expected
+#include <include_instead/private2.h> // no warning expected
+#include <include_instead/private3.h> // no warning expected
diff --git a/clang/test/Preprocessor/Inputs/include_instead/public-empty.h b/clang/test/Preprocessor/Inputs/include_instead/public-empty.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/Inputs/include_instead/public-empty.h
@@ -0,0 +1 @@
+// This file simply needs to exist.
diff --git a/clang/test/Preprocessor/include_instead.cpp b/clang/test/Preprocessor/include_instead.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/include_instead.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -I %S/Inputs %s
+
+#include <include_instead/bad-syntax.h>
+#include <include_instead/non-system-header.h>
+
+#include <include_instead/private1.h>
+// expected-error@-1{{header '<include_instead/private1.h>' is an implementation detail; #include '<include_instead/public-before.h>' instead}}
+
+#include "include_instead/private2.h"
+// expected-error@-1{{header '"include_instead/private2.h"' is an implementation detail; #include either '<include_instead/public-before.h>' or '"include_instead/public-after.h"' instead}}
+
+#include <include_instead/private3.h>
+// expected-error@-1{{header '<include_instead/private3.h>' is an implementation detail; #include one of {'<include_instead/public-after.h>', '<include_instead/public-empty.h>', '"include_instead/public-before.h"'} instead}}
+
+#include <include_instead/public-before.h>
+#include <include_instead/public-after.h>
diff --git a/clang/test/Preprocessor/include_instead_file_not_found.cpp b/clang/test/Preprocessor/include_instead_file_not_found.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/Preprocessor/include_instead_file_not_found.cpp
@@ -0,0 +1,2 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -I %S/Inputs %s
+#include <include_instead/file-not-found.h>