Index: clang-tidy/ClangTidy.cpp
===================================================================
--- clang-tidy/ClangTidy.cpp
+++ clang-tidy/ClangTidy.cpp
@@ -72,13 +72,14 @@
       SmallString<64> CheckName(AnalyzerCheckNamePrefix);
       CheckName += PD->getCheckName();
       Context.diag(CheckName, PD->getLocation().asLocation(),
-                   PD->getShortDescription())
+                   PD->getShortDescription(), /*FixDescription*/ "")
           << PD->path.back()->getRanges();
 
       for (const auto &DiagPiece :
            PD->path.flatten(/*ShouldFlattenMacros=*/true)) {
         Context.diag(CheckName, DiagPiece->getLocation().asLocation(),
-                     DiagPiece->getString(), DiagnosticIDs::Note)
+                     DiagPiece->getString(), /*FixDescription*/ "",
+                     DiagnosticIDs::Note)
             << DiagPiece->getRanges();
       }
     }
Index: clang-tidy/ClangTidyCheck.h
===================================================================
--- clang-tidy/ClangTidyCheck.h
+++ clang-tidy/ClangTidyCheck.h
@@ -92,6 +92,22 @@
   /// work in here.
   virtual void check(const ast_matchers::MatchFinder::MatchResult &Result) {}
 
+  /// A short human readable description about the check fix. It should
+  /// descripe what the check fix will do, so users can rely on it to know the
+  /// fix intention without viewing the actual code change.
+  ///
+  /// Example: "Convert to 'switch'"; "Removed unused using"; "Use make_unique".
+  ///
+  /// The description will be attached to ``ClangTidyError``. Returning empty
+  /// string indicates the check doesn't provide this information.
+  ///
+  /// Caveats:
+  ///   - The interface may not fit well with a check that produces different
+  ///     fixes for different cases.
+  ///   - clang compiler diagnostics and clang static analyzer diagnostics are
+  ///     not supported.
+  virtual llvm::StringRef fixDescription() { return ""; }
+
   /// \brief Add a diagnostic with the check's name.
   DiagnosticBuilder diag(SourceLocation Loc, StringRef Description,
                          DiagnosticIDs::Level Level = DiagnosticIDs::Warning);
Index: clang-tidy/ClangTidyCheck.cpp
===================================================================
--- clang-tidy/ClangTidyCheck.cpp
+++ clang-tidy/ClangTidyCheck.cpp
@@ -20,7 +20,7 @@
 
 DiagnosticBuilder ClangTidyCheck::diag(SourceLocation Loc, StringRef Message,
                                        DiagnosticIDs::Level Level) {
-  return Context->diag(CheckName, Loc, Message, Level);
+  return Context->diag(CheckName, Loc, Message, fixDescription(), Level);
 }
 
 void ClangTidyCheck::run(const ast_matchers::MatchFinder::MatchResult &Result) {
Index: clang-tidy/ClangTidyDiagnosticConsumer.h
===================================================================
--- clang-tidy/ClangTidyDiagnosticConsumer.h
+++ clang-tidy/ClangTidyDiagnosticConsumer.h
@@ -16,6 +16,7 @@
 #include "clang/Tooling/Core/Diagnostic.h"
 #include "clang/Tooling/Refactoring.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/Support/Regex.h"
 #include "llvm/Support/Timer.h"
@@ -45,6 +46,11 @@
                  bool IsWarningAsError);
 
   bool IsWarningAsError;
+  // A short descrpition of the clang-tidy fix.
+  // Empty if the ClangTidyError doesn't provide any fixes.
+  //
+  // FIXME: this should move to tooling::Diagnostic.
+  std::string FixDescription;
 };
 
 /// \brief Read-only set of strings represented as a list of positive and
@@ -116,7 +122,7 @@
   /// tablegen'd diagnostic IDs.
   /// FIXME: Figure out a way to manage ID spaces.
   DiagnosticBuilder diag(StringRef CheckName, SourceLocation Loc,
-                         StringRef Message,
+                         StringRef Message, StringRef CheckFixDescription,
                          DiagnosticIDs::Level Level = DiagnosticIDs::Warning);
 
   /// \brief Sets the \c SourceManager of the used \c DiagnosticsEngine.
@@ -140,6 +146,10 @@
   /// diagnostic ID.
   std::string getCheckName(unsigned DiagnosticID) const;
 
+  /// \brief Returns the fix description of the clang-tidy check which produced
+  /// this diagnostic ID.
+  std::string getCheckFixDescription(unsigned DiagnosticID) const;
+
   /// \brief Returns \c true if the check is enabled for the \c CurrentFile.
   ///
   /// The \c CurrentFile can be changed using \c setCurrentFile.
@@ -209,7 +219,8 @@
 
   std::string CurrentBuildDirectory;
 
-  llvm::DenseMap<unsigned, std::string> CheckNamesByDiagnosticID;
+  llvm::DenseMap<unsigned, std::pair<std::string, std::string>>
+      CheckNamesByDiagnosticID;
 
   bool Profile;
   std::string ProfilePrefix;
Index: clang-tidy/ClangTidyDiagnosticConsumer.cpp
===================================================================
--- clang-tidy/ClangTidyDiagnosticConsumer.cpp
+++ clang-tidy/ClangTidyDiagnosticConsumer.cpp
@@ -190,11 +190,12 @@
 
 DiagnosticBuilder ClangTidyContext::diag(
     StringRef CheckName, SourceLocation Loc, StringRef Description,
+    StringRef CheckFixDescription,
     DiagnosticIDs::Level Level /* = DiagnosticIDs::Warning*/) {
   assert(Loc.isValid());
   unsigned ID = DiagEngine->getDiagnosticIDs()->getCustomDiagID(
       Level, (Description + " [" + CheckName + "]").str());
-  CheckNamesByDiagnosticID.try_emplace(ID, CheckName);
+  CheckNamesByDiagnosticID[ID] = {CheckName, CheckFixDescription};
   return DiagEngine->Report(Loc, ID);
 }
 
@@ -259,10 +260,17 @@
       DiagEngine->getDiagnosticIDs()->getWarningOptionForDiag(DiagnosticID);
   if (!ClangWarningOption.empty())
     return "clang-diagnostic-" + ClangWarningOption;
-  llvm::DenseMap<unsigned, std::string>::const_iterator I =
-      CheckNamesByDiagnosticID.find(DiagnosticID);
+  auto I = CheckNamesByDiagnosticID.find(DiagnosticID);
   if (I != CheckNamesByDiagnosticID.end())
-    return I->second;
+    return I->second.first;
+  return "";
+}
+
+std::string
+ClangTidyContext::getCheckFixDescription(unsigned DiagnosticID) const {
+  auto I = CheckNamesByDiagnosticID.find(DiagnosticID);
+  if (I != CheckNamesByDiagnosticID.end())
+    return I->second.second;
   return "";
 }
 
@@ -449,6 +457,9 @@
     Loc = FullSourceLoc(Info.getLocation(), Info.getSourceManager());
   Converter.emitDiagnostic(Loc, DiagLevel, Message, Info.getRanges(),
                            Info.getFixItHints());
+  // Populate the fix description if the diagnostic has fixes.
+  if (!Errors.back().Fix.empty())
+    Errors.back().FixDescription = Context.getCheckFixDescription(Info.getID());
 
   if (Info.hasSourceManager())
     checkFilters(Info.getLocation(), Info.getSourceManager());