Index: clang-tidy/misc/StringConstructorCheck.cpp
===================================================================
--- clang-tidy/misc/StringConstructorCheck.cpp
+++ clang-tidy/misc/StringConstructorCheck.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "StringConstructorCheck.h"
+#include "../utils/FixItHintUtils.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 
@@ -54,7 +55,7 @@
       isDefinition(),
       hasType(pointerType(pointee(isAnyCharacter(), isConstQualified()))),
       hasInitializer(ignoringParenImpCasts(BoundStringLiteral)));
-  auto ConstStrLiteral = expr(ignoringParenImpCasts(anyOf(
+  const auto ConstStrLiteral = expr(ignoringParenImpCasts(anyOf(
       BoundStringLiteral, declRefExpr(hasDeclaration(anyOf(
                               ConstPtrStrLiteralDecl, ConstStrLiteralDecl))))));
 
@@ -88,7 +89,7 @@
               // Detect the expression: string("...", 0);
               hasArgument(1, ZeroExpr.bind("empty-string")),
               // Detect the expression: string("...", -4);
-              hasArgument(1, NegativeExpr.bind("negative-length")),              
+              hasArgument(1, NegativeExpr.bind("negative-length")),
               // Detect the expression: string("lit", 0x1234567);
               hasArgument(1, LargeLengthExpr.bind("large-length")),
               // Detect the expression: string("lit", 5)
@@ -100,11 +101,26 @@
 }
 
 void StringConstructorCheck::check(const MatchFinder::MatchResult &Result) {
-  const auto *E = Result.Nodes.getNodeAs<Expr>("constructor");
+  const ASTContext &Ctx = *Result.Context;
+  const auto *E = Result.Nodes.getNodeAs<CXXConstructExpr>("constructor");
+  assert(E && "missing constructor expression");
   SourceLocation Loc = E->getLocStart();
 
   if (Result.Nodes.getNodeAs<Expr>("swapped-parameter")) {
-    diag(Loc, "constructor parameters are probably swapped");
+    auto D = diag(Loc, "constructor parameters are probably swapped");
+
+    SourceRange Param1 = E->getArg(0)->getSourceRange();
+    SourceRange Param2 = E->getArg(1)->getSourceRange();
+    StringRef Param1String =
+        utils::create_fix_it::getSourceRangeAsString(Ctx, Param1);
+    StringRef Param2String =
+        utils::create_fix_it::getSourceRangeAsString(Ctx, Param2);
+    if (!Param1String.empty() && !Param2String.empty()) {
+      D << FixItHint::CreateReplacement(CharSourceRange::getTokenRange(Param1),
+                                        Param2String)
+        << FixItHint::CreateReplacement(CharSourceRange::getTokenRange(Param2),
+                                        Param1String);
+    }
   } else if (Result.Nodes.getNodeAs<Expr>("empty-string")) {
     diag(Loc, "constructor creating an empty string");
   } else if (Result.Nodes.getNodeAs<Expr>("negative-length")) {
Index: clang-tidy/misc/SwappedArgumentsCheck.cpp
===================================================================
--- clang-tidy/misc/SwappedArgumentsCheck.cpp
+++ clang-tidy/misc/SwappedArgumentsCheck.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "SwappedArgumentsCheck.h"
+#include "../utils/FixItHintUtils.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/Lex/Lexer.h"
 #include "llvm/ADT/SmallPtrSet.h"
@@ -46,24 +47,8 @@
          Cast->getCastKind() == CK_PointerToBoolean;
 }
 
-/// \brief Get a StringRef representing a SourceRange.
-static StringRef getAsString(const MatchFinder::MatchResult &Result,
-                             SourceRange R) {
-  const SourceManager &SM = *Result.SourceManager;
-  // Don't even try to resolve macro or include contraptions. Not worth emitting
-  // a fixit for.
-  if (R.getBegin().isMacroID() ||
-      !SM.isWrittenInSameFile(R.getBegin(), R.getEnd()))
-    return StringRef();
-
-  const char *Begin = SM.getCharacterData(R.getBegin());
-  const char *End = SM.getCharacterData(Lexer::getLocForEndOfToken(
-      R.getEnd(), 0, SM, Result.Context->getLangOpts()));
-
-  return StringRef(Begin, End - Begin);
-}
-
 void SwappedArgumentsCheck::check(const MatchFinder::MatchResult &Result) {
+  const ASTContext &Ctx = *Result.Context;
   auto *Call = Result.Nodes.getStmtAs<CallExpr>("call");
 
   llvm::SmallPtrSet<const Expr *, 4> UsedArgs;
@@ -108,8 +93,10 @@
         << LHS->getType() << LHSFrom->getType() << RHS->getType()
         << RHSFrom->getType() << LHSRange << RHSRange;
 
-    StringRef RHSString = getAsString(Result, RHSRange);
-    StringRef LHSString = getAsString(Result, LHSRange);
+    StringRef RHSString =
+        utils::create_fix_it::getSourceRangeAsString(Ctx, RHSRange);
+    StringRef LHSString =
+        utils::create_fix_it::getSourceRangeAsString(Ctx, LHSRange);
     if (!LHSString.empty() && !RHSString.empty()) {
       D << FixItHint::CreateReplacement(
                CharSourceRange::getTokenRange(LHSRange), RHSString)
Index: clang-tidy/utils/FixItHintUtils.h
===================================================================
--- clang-tidy/utils/FixItHintUtils.h
+++ clang-tidy/utils/FixItHintUtils.h
@@ -24,6 +24,9 @@
 /// \brief Creates fix to make VarDecl const qualified.
 FixItHint changeVarDeclToConst(const VarDecl &Var);
 
+/// \brief Get a StringRef representing a SourceRange.
+StringRef getSourceRangeAsString(const ASTContext &Context, SourceRange R);
+
 } // namespace create_fix_it
 } // utils
 } // namespace tidy
Index: clang-tidy/utils/FixItHintUtils.cpp
===================================================================
--- clang-tidy/utils/FixItHintUtils.cpp
+++ clang-tidy/utils/FixItHintUtils.cpp
@@ -30,6 +30,21 @@
   return FixItHint::CreateInsertion(Var.getTypeSpecStartLoc(), "const ");
 }
 
+StringRef getSourceRangeAsString(const ASTContext &Context, SourceRange R) {
+  const SourceManager &SM = Context.getSourceManager();
+  // Don't even try to resolve macro or include contraptions. Not worth emitting
+  // a fixit for.
+  if (R.getBegin().isMacroID() ||
+      !SM.isWrittenInSameFile(R.getBegin(), R.getEnd()))
+    return StringRef();
+
+  const char *Begin = SM.getCharacterData(R.getBegin());
+  const char *End = SM.getCharacterData(
+      Lexer::getLocForEndOfToken(R.getEnd(), 0, SM, Context.getLangOpts()));
+
+  return StringRef(Begin, End - Begin);
+}
+
 } // namespace create_fix_it
 } // namespace utils
 } // namespace tidy
Index: test/clang-tidy/misc-string-constructor.cpp
===================================================================
--- test/clang-tidy/misc-string-constructor.cpp
+++ test/clang-tidy/misc-string-constructor.cpp
@@ -22,8 +22,10 @@
 void Test() {
   std::string str('x', 4);
   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructor parameters are probably swapped [misc-string-constructor]
+  // CHECK-FIXES: std::string str(4, 'x');  
   std::wstring wstr(L'x', 4);
   // CHECK-MESSAGES: [[@LINE-1]]:16: warning: constructor parameters are probably swapped
+  // CHECK-FIXES: std::wstring wstr(4, L'x');    
   std::string s0(0, 'x');
   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructor creating an empty string
   std::string s1(-4, 'x');