diff --git a/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp b/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp
index 1f1dc07351ba43..4b0ef1b3f4ee09 100644
--- a/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp
@@ -59,10 +59,8 @@ void DurationFactoryFloatCheck::check(const MatchFinder::MatchResult &Result) {
     SimpleArg = stripFloatLiteralFraction(Result, *Arg);
 
   if (SimpleArg) {
-    diag(MatchedCall->getBeginLoc(),
-         (llvm::Twine("use the integer version of absl::") +
-          MatchedCall->getDirectCallee()->getName())
-             .str())
+    diag(MatchedCall->getBeginLoc(), "use the integer version of absl::%0")
+        << MatchedCall->getDirectCallee()->getName()
         << FixItHint::CreateReplacement(Arg->getSourceRange(), *SimpleArg);
   }
 }
diff --git a/clang-tools-extra/clang-tidy/abseil/StringFindStartswithCheck.cpp b/clang-tools-extra/clang-tidy/abseil/StringFindStartswithCheck.cpp
index 850631300f7ab0..aa43e7dc388512 100644
--- a/clang-tools-extra/clang-tidy/abseil/StringFindStartswithCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/StringFindStartswithCheck.cpp
@@ -83,24 +83,18 @@ void StringFindStartswithCheck::check(const MatchFinder::MatchResult &Result) {
       Context.getLangOpts());
 
   // Create the StartsWith string, negating if comparison was "!=".
-  bool Neg = ComparisonExpr->getOpcodeStr() == "!=";
-  StringRef StartswithStr;
-  if (Neg) {
-    StartswithStr = "!absl::StartsWith";
-  } else {
-    StartswithStr = "absl::StartsWith";
-  }
+  bool Neg = ComparisonExpr->getOpcode() == BO_NE;
 
   // Create the warning message and a FixIt hint replacing the original expr.
-  auto Diagnostic =
-      diag(ComparisonExpr->getBeginLoc(),
-           (StringRef("use ") + StartswithStr + " instead of find() " +
-            ComparisonExpr->getOpcodeStr() + " 0")
-               .str());
+  auto Diagnostic = diag(ComparisonExpr->getBeginLoc(),
+                         "use %select{absl::StartsWith|!absl::StartsWith}0 "
+                         "instead of find() %select{==|!=}0 0")
+                    << Neg;
 
   Diagnostic << FixItHint::CreateReplacement(
       ComparisonExpr->getSourceRange(),
-      (StartswithStr + "(" + HaystackExprCode + ", " + NeedleExprCode + ")")
+      ((Neg ? "!absl::StartsWith(" : "absl::StartsWith(") + HaystackExprCode +
+       ", " + NeedleExprCode + ")")
           .str());
 
   // Create a preprocessor #include FixIt hint (CreateIncludeInsertion checks
diff --git a/clang-tools-extra/clang-tidy/bugprone/ExceptionEscapeCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ExceptionEscapeCheck.cpp
index a78e93aff55078..85af540b48fbe5 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ExceptionEscapeCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ExceptionEscapeCheck.cpp
@@ -72,10 +72,8 @@ void ExceptionEscapeCheck::check(const MatchFinder::MatchResult &Result) {
       utils::ExceptionAnalyzer::State::Throwing)
     // FIXME: We should provide more information about the exact location where
     // the exception is thrown, maybe the full path the exception escapes
-    diag(MatchedDecl->getLocation(),
-         "an exception may be thrown in function %0 "
-
-         "which should not throw exceptions")
+    diag(MatchedDecl->getLocation(), "an exception may be thrown in function "
+                                     "%0 which should not throw exceptions")
         << MatchedDecl;
 }
 
diff --git a/clang-tools-extra/clang-tidy/bugprone/ParentVirtualCallCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ParentVirtualCallCheck.cpp
index 6b8b7fc7ffc54e..8f21678f0c9f1f 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ParentVirtualCallCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ParentVirtualCallCheck.cpp
@@ -137,9 +137,9 @@ void ParentVirtualCallCheck::check(const MatchFinder::MatchResult &Result) {
   assert(Member->getQualifierLoc().getSourceRange().getBegin().isValid());
   auto Diag = diag(Member->getQualifierLoc().getSourceRange().getBegin(),
                    "qualified name '%0' refers to a member overridden "
-                   "in subclass%1; did you mean %2?")
+                   "in %plural{1:subclass|:subclasses}1; did you mean %2?")
               << getExprAsString(*Member, *Result.Context)
-              << (Parents.size() > 1 ? "es" : "") << ParentsStr;
+              << static_cast<unsigned>(Parents.size()) << ParentsStr;
 
   // Propose a fix if there's only one parent class...
   if (Parents.size() == 1 &&
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
index 6b40e525f7dd50..f4468367ffa325 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
@@ -439,10 +439,9 @@ void ProTypeMemberInitCheck::checkMissingMemberInitializer(
 
   DiagnosticBuilder Diag =
       diag(Ctor ? Ctor->getBeginLoc() : ClassDecl.getLocation(),
-           IsUnion
-               ? "union constructor should initialize one of these fields: %0"
-               : "constructor does not initialize these fields: %0")
-      << toCommaSeparatedString(OrderedFields, AllFieldsToInit);
+           "%select{|union }0constructor %select{does not|should}0 initialize "
+           "%select{|one of }0these fields: %1")
+      << IsUnion << toCommaSeparatedString(OrderedFields, AllFieldsToInit);
 
   // Do not propose fixes for constructors in macros since we cannot place them
   // correctly.
diff --git a/clang-tools-extra/clang-tidy/llvm/PreferRegisterOverUnsignedCheck.cpp b/clang-tools-extra/clang-tidy/llvm/PreferRegisterOverUnsignedCheck.cpp
index 17e75abd724ce5..6e8cabeb4e64ee 100644
--- a/clang-tools-extra/clang-tidy/llvm/PreferRegisterOverUnsignedCheck.cpp
+++ b/clang-tools-extra/clang-tidy/llvm/PreferRegisterOverUnsignedCheck.cpp
@@ -38,27 +38,27 @@ void PreferRegisterOverUnsignedCheck::check(
   const auto *VarType = Result.Nodes.getNodeAs<QualType>("varType");
   const auto *UserVarDecl = Result.Nodes.getNodeAs<VarDecl>("var");
 
-  StringRef Replacement = "llvm::Register";
+  bool NeedsQualification = true;
   const DeclContext *Context = UserVarDecl->getDeclContext();
   while (Context) {
     if (const auto *Namespace = dyn_cast<NamespaceDecl>(Context))
       if (isa<TranslationUnitDecl>(Namespace->getDeclContext()) &&
           Namespace->getName() == "llvm")
-        Replacement = "Register";
+        NeedsQualification = false;
     for (const auto *UsingDirective : Context->using_directives()) {
       const NamespaceDecl *Namespace = UsingDirective->getNominatedNamespace();
       if (isa<TranslationUnitDecl>(Namespace->getDeclContext()) &&
           Namespace->getName() == "llvm")
-        Replacement = "Register";
+        NeedsQualification = false;
     }
     Context = Context->getParent();
   }
   diag(UserVarDecl->getLocation(),
-       "variable %0 declared as %1; use '%2' instead")
-      << UserVarDecl << *VarType << Replacement
+       "variable %0 declared as %1; use '%select{|llvm::}2Register' instead")
+      << UserVarDecl << *VarType << NeedsQualification
       << FixItHint::CreateReplacement(
              UserVarDecl->getTypeSourceInfo()->getTypeLoc().getSourceRange(),
-             Replacement);
+             NeedsQualification ? "llvm::Register" : "Register");
 }
 
 } // namespace llvm_check
diff --git a/clang-tools-extra/clang-tidy/misc/UnconventionalAssignOperatorCheck.cpp b/clang-tools-extra/clang-tidy/misc/UnconventionalAssignOperatorCheck.cpp
index 5fc973223ea3b1..594c83a30e7eff 100644
--- a/clang-tools-extra/clang-tidy/misc/UnconventionalAssignOperatorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/UnconventionalAssignOperatorCheck.cpp
@@ -73,21 +73,18 @@ void UnconventionalAssignOperatorCheck::check(
   if (const auto *RetStmt = Result.Nodes.getNodeAs<ReturnStmt>("returnStmt")) {
     diag(RetStmt->getBeginLoc(), "operator=() should always return '*this'");
   } else {
-    static const char *const Messages[][2] = {
-        {"ReturnType", "operator=() should return '%0&'"},
-        {"ArgumentType",
-         getLangOpts().CPlusPlus11
-             ? "operator=() should take '%0 const&', '%0&&' or '%0'"
-             : "operator=() should take '%0 const&' or '%0'"},
-        {"cv", "operator=() should not be marked '%1'"}};
-
     const auto *Method = Result.Nodes.getNodeAs<CXXMethodDecl>("method");
-    for (const auto &Message : Messages) {
-      if (Result.Nodes.getNodeAs<Decl>(Message[0]))
-        diag(Method->getBeginLoc(), Message[1])
-            << Method->getParent()->getName()
-            << (Method->isConst() ? "const" : "virtual");
-    }
+    if (Result.Nodes.getNodeAs<CXXMethodDecl>("ReturnType"))
+      diag(Method->getBeginLoc(), "operator=() should return '%0&'")
+          << Method->getParent()->getName();
+    if (Result.Nodes.getNodeAs<CXXMethodDecl>("ArgumentType"))
+      diag(Method->getBeginLoc(),
+           "operator=() should take '%0 const&'%select{|, '%0&&'}1 or '%0'")
+          << Method->getParent()->getName() << getLangOpts().CPlusPlus11;
+    if (Result.Nodes.getNodeAs<CXXMethodDecl>("cv"))
+      diag(Method->getBeginLoc(),
+           "operator=() should not be marked '%select{const|virtual}0'")
+          << !Method->isConst();
   }
 }
 
diff --git a/clang-tools-extra/clang-tidy/misc/UniqueptrResetReleaseCheck.cpp b/clang-tools-extra/clang-tidy/misc/UniqueptrResetReleaseCheck.cpp
index 98b53e33bdaf28..f1e2cbe1fed08a 100644
--- a/clang-tools-extra/clang-tidy/misc/UniqueptrResetReleaseCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/UniqueptrResetReleaseCheck.cpp
@@ -110,19 +110,22 @@ void UniqueptrResetReleaseCheck::check(const MatchFinder::MatchResult &Result) {
     LeftText = "*" + LeftText;
   if (ReleaseMember->isArrow())
     RightText = "*" + RightText;
-  std::string DiagText;
+  bool IsMove = false;
   // Even if x was rvalue, *x is not rvalue anymore.
   if (!Right->isRValue() || ReleaseMember->isArrow()) {
     RightText = "std::move(" + RightText + ")";
-    DiagText = "prefer ptr1 = std::move(ptr2) over ptr1.reset(ptr2.release())";
-  } else {
-    DiagText =
-        "prefer ptr = ReturnUnique() over ptr.reset(ReturnUnique().release())";
+    IsMove = true;
   }
+
   std::string NewText = LeftText + " = " + RightText;
 
-  diag(ResetMember->getExprLoc(), DiagText) << FixItHint::CreateReplacement(
-      CharSourceRange::getTokenRange(ResetCall->getSourceRange()), NewText);
+  diag(ResetMember->getExprLoc(),
+       "prefer ptr = %select{std::move(ptr2)|ReturnUnique()}0 over "
+       "ptr.reset(%select{ptr2|ReturnUnique()}0.release())")
+      << !IsMove
+      << FixItHint::CreateReplacement(
+             CharSourceRange::getTokenRange(ResetCall->getSourceRange()),
+             NewText);
 }
 
 } // namespace misc
diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
index bc586d30b378cb..872dd186759408 100644
--- a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
@@ -57,13 +57,10 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
 void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *ArrayType = Result.Nodes.getNodeAs<TypeLoc>("typeloc");
 
-  static constexpr llvm::StringLiteral UseArray = llvm::StringLiteral(
-      "do not declare C-style arrays, use std::array<> instead");
-  static constexpr llvm::StringLiteral UseVector = llvm::StringLiteral(
-      "do not declare C VLA arrays, use std::vector<> instead");
-
   diag(ArrayType->getBeginLoc(),
-       ArrayType->getTypePtr()->isVariableArrayType() ? UseVector : UseArray);
+       "do not declare %select{C-style|C VLA}0 arrays, use "
+       "%select{std::array<>|std::vector<>}0 instead")
+      << ArrayType->getTypePtr()->isVariableArrayType();
 }
 
 } // namespace modernize
diff --git a/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.cpp
index 5c79e860244aa3..0f10dd375a80e0 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.cpp
@@ -245,8 +245,6 @@ void UseEqualsDefaultCheck::registerMatchers(MatchFinder *Finder) {
 }
 
 void UseEqualsDefaultCheck::check(const MatchFinder::MatchResult &Result) {
-  std::string SpecialFunctionName;
-
   // Both CXXConstructorDecl and CXXDestructorDecl inherit from CXXMethodDecl.
   const auto *SpecialFunctionDecl =
       Result.Nodes.getNodeAs<CXXMethodDecl>(SpecialFunction);
@@ -276,14 +274,14 @@ void UseEqualsDefaultCheck::check(const MatchFinder::MatchResult &Result) {
                   bodyEmpty(Result.Context, Body);
 
   std::vector<FixItHint> RemoveInitializers;
-
+  unsigned MemberType;
   if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(SpecialFunctionDecl)) {
     if (Ctor->getNumParams() == 0) {
-      SpecialFunctionName = "default constructor";
+      MemberType = 0;
     } else {
       if (!isCopyConstructorAndCanBeDefaulted(Result.Context, Ctor))
         return;
-      SpecialFunctionName = "copy constructor";
+      MemberType = 1;
       // If there are constructor initializers, they must be removed.
       for (const auto *Init : Ctor->inits()) {
         RemoveInitializers.emplace_back(
@@ -291,11 +289,11 @@ void UseEqualsDefaultCheck::check(const MatchFinder::MatchResult &Result) {
       }
     }
   } else if (isa<CXXDestructorDecl>(SpecialFunctionDecl)) {
-    SpecialFunctionName = "destructor";
+    MemberType = 2;
   } else {
     if (!isCopyAssignmentAndCanBeDefaulted(Result.Context, SpecialFunctionDecl))
       return;
-    SpecialFunctionName = "copy-assignment operator";
+    MemberType = 3;
   }
 
   // The location of the body is more useful inside a macro as spelling and
@@ -304,8 +302,11 @@ void UseEqualsDefaultCheck::check(const MatchFinder::MatchResult &Result) {
   if (Location.isMacroID())
     Location = Body->getBeginLoc();
 
-  auto Diag = diag(Location, "use '= default' to define a trivial " +
-                                 SpecialFunctionName);
+  auto Diag = diag(
+      Location,
+      "use '= default' to define a trivial %select{default constructor|copy "
+      "constructor|destructor|copy-assignment operator}0");
+  Diag << MemberType;
 
   if (ApplyFix) {
     // Skipping comments, check for a semicolon after Body->getSourceRange()
diff --git a/clang-tools-extra/clang-tidy/modernize/UseNodiscardCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseNodiscardCheck.cpp
index a2e6a7a2807610..f992e9de37f536 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseNodiscardCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseNodiscardCheck.cpp
@@ -120,8 +120,8 @@ void UseNodiscardCheck::check(const MatchFinder::MatchResult &Result) {
 
   ASTContext &Context = *Result.Context;
 
-  auto Diag = diag(RetLoc, "function %0 should be marked " + NoDiscardMacro)
-              << MatchedDecl;
+  auto Diag = diag(RetLoc, "function %0 should be marked %1")
+              << MatchedDecl << NoDiscardMacro;
 
   // Check for the existence of the keyword being used as the ``[[nodiscard]]``.
   if (!doesNoDiscardMacroExist(Context, NoDiscardMacro))
diff --git a/clang-tools-extra/clang-tidy/modernize/UseTransparentFunctorsCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseTransparentFunctorsCheck.cpp
index cbd11f022d59db..02b602ea1a0f70 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseTransparentFunctorsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseTransparentFunctorsCheck.cpp
@@ -64,7 +64,7 @@ void UseTransparentFunctorsCheck::registerMatchers(MatchFinder *Finder) {
                      this);
 }
 
-static const StringRef Message = "prefer transparent functors '%0'";
+static const StringRef Message = "prefer transparent functors '%0<>'";
 
 template <typename T> static T getInnerTypeLocAs(TypeLoc Loc) {
   T Result;
@@ -81,8 +81,7 @@ void UseTransparentFunctorsCheck::check(
       Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("FunctorClass");
   if (const auto *FuncInst =
           Result.Nodes.getNodeAs<CXXConstructExpr>("FuncInst")) {
-    diag(FuncInst->getBeginLoc(), Message)
-        << (FuncClass->getName() + "<>").str();
+    diag(FuncInst->getBeginLoc(), Message) << FuncClass->getName();
     return;
   }
 
@@ -119,7 +118,7 @@ void UseTransparentFunctorsCheck::check(
   SourceLocation ReportLoc = FunctorLoc.getLocation();
   if (ReportLoc.isInvalid())
     return;
-  diag(ReportLoc, Message) << (FuncClass->getName() + "<>").str()
+  diag(ReportLoc, Message) << FuncClass->getName()
                            << FixItHint::CreateRemoval(
                                   FunctorTypeLoc.getArgLoc(0).getSourceRange());
 }
diff --git a/clang-tools-extra/clang-tidy/performance/MoveConstructorInitCheck.cpp b/clang-tools-extra/clang-tidy/performance/MoveConstructorInitCheck.cpp
index 34d8e720629098..dd6e5a816ded1d 100644
--- a/clang-tools-extra/clang-tidy/performance/MoveConstructorInitCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/MoveConstructorInitCheck.cpp
@@ -74,8 +74,9 @@ void MoveConstructorInitCheck::check(const MatchFinder::MatchResult &Result) {
     // There's a move constructor candidate that the caller probably intended
     // to call instead.
     diag(Initializer->getSourceLocation(),
-         "move constructor initializes %0 by calling a copy constructor")
-        << (Initializer->isBaseInitializer() ? "base class" : "class member");
+         "move constructor initializes %select{class member|base class}0 by "
+         "calling a copy constructor")
+        << Initializer->isBaseInitializer();
     diag(CopyCtor->getLocation(), "copy constructor being called",
          DiagnosticIDs::Note);
     diag(Candidate->getLocation(), "candidate move constructor here",
diff --git a/clang-tools-extra/clang-tidy/performance/NoexceptMoveConstructorCheck.cpp b/clang-tools-extra/clang-tidy/performance/NoexceptMoveConstructorCheck.cpp
index d23f0ab0cf44d8..f87f214945fa23 100644
--- a/clang-tools-extra/clang-tidy/performance/NoexceptMoveConstructorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/NoexceptMoveConstructorCheck.cpp
@@ -29,11 +29,11 @@ void NoexceptMoveConstructorCheck::registerMatchers(MatchFinder *Finder) {
 void NoexceptMoveConstructorCheck::check(
     const MatchFinder::MatchResult &Result) {
   if (const auto *Decl = Result.Nodes.getNodeAs<CXXMethodDecl>("decl")) {
-    StringRef MethodType = "assignment operator";
+    bool IsConstructor = false;
     if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(Decl)) {
       if (!Ctor->isMoveConstructor())
         return;
-      MethodType = "constructor";
+      IsConstructor = true;
     } else if (!Decl->isMoveAssignmentOperator()) {
       return;
     }
@@ -44,9 +44,10 @@ void NoexceptMoveConstructorCheck::check(
       return;
 
     if (!isNoexceptExceptionSpec(ProtoType->getExceptionSpecType())) {
-      auto Diag =
-          diag(Decl->getLocation(), "move %0s should be marked noexcept")
-          << MethodType;
+      auto Diag = diag(Decl->getLocation(),
+                       "move %select{assignment operator|constructor}0s should "
+                       "be marked noexcept")
+                  << IsConstructor;
       // Add FixIt hints.
       SourceManager &SM = *Result.SourceManager;
       assert(Decl->getNumParams() > 0);
@@ -68,8 +69,9 @@ void NoexceptMoveConstructorCheck::check(
       E = E->IgnoreImplicit();
       if (!isa<CXXBoolLiteralExpr>(E)) {
         diag(E->getExprLoc(),
-             "noexcept specifier on the move %0 evaluates to 'false'")
-            << MethodType;
+             "noexcept specifier on the move %select{assignment "
+             "operator|constructor}0 evaluates to 'false'")
+            << IsConstructor;
       }
     }
   }
diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp
index f63dbab093581b..0cc9a442630218 100644
--- a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp
+++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp
@@ -206,13 +206,10 @@ void UnnecessaryCopyInitialization::handleCopyFromMethodReturn(
 
   auto Diagnostic =
       diag(Var.getLocation(),
-           IsConstQualified ? "the const qualified variable %0 is "
-                              "copy-constructed from a const reference; "
-                              "consider making it a const reference"
-                            : "the variable %0 is copy-constructed from a "
-                              "const reference but is only used as const "
-                              "reference; consider making it a const reference")
-      << &Var;
+           "the %select{|const qualified }0variable %1 is copy-constructed "
+           "from a const reference%select{ but is only used as const "
+           "reference|}0; consider making it a const reference")
+      << IsConstQualified << &Var;
   if (IssueFix)
     recordFixes(Var, Context, Diagnostic);
 }
diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
index e3dae9a135581d..2a9f9b70517758 100644
--- a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
@@ -137,13 +137,10 @@ void UnnecessaryValueParamCheck::check(const MatchFinder::MatchResult &Result) {
 
   auto Diag =
       diag(Param->getLocation(),
-           IsConstQualified ? "the const qualified parameter %0 is "
-                              "copied for each invocation; consider "
-                              "making it a reference"
-                            : "the parameter %0 is copied for each "
-                              "invocation but only used as a const reference; "
-                              "consider making it a const reference")
-      << paramNameOrIndex(Param->getName(), Index);
+           "the %select{|const qualified }0parameter %1 is copied for each "
+           "invocation%select{ but only used as a const reference|}0; consider "
+           "making it a %select{const |}0reference")
+      << IsConstQualified << paramNameOrIndex(Param->getName(), Index);
   // Do not propose fixes when:
   // 1. the ParmVarDecl is in a macro, since we cannot place them correctly
   // 2. the function is virtual as it might break overrides
diff --git a/clang-tools-extra/clang-tidy/portability/SIMDIntrinsicsCheck.cpp b/clang-tools-extra/clang-tidy/portability/SIMDIntrinsicsCheck.cpp
index 65d7c1746b18f5..8ea00a0b8ed6ad 100644
--- a/clang-tools-extra/clang-tidy/portability/SIMDIntrinsicsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/portability/SIMDIntrinsicsCheck.cpp
@@ -12,6 +12,7 @@
 #include "clang/Basic/TargetInfo.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/Triple.h"
+#include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Regex.h"
 
 using namespace clang::ast_matchers;
@@ -130,20 +131,18 @@ void SIMDIntrinsicsCheck::check(const MatchFinder::MatchResult &Result) {
 
   // We have found a std::simd replacement.
   if (!New.empty()) {
-    std::string Message;
     // If Suggest is true, give a P0214 alternative, otherwise point it out it
     // is non-portable.
     if (Suggest) {
-      Message = (Twine("'") + Old + "' can be replaced by " + New).str();
-      Message = llvm::Regex("\\$std").sub(Std, Message);
-      Message =
-          llvm::Regex("\\$simd").sub((Std.str() + "::simd").str(), Message);
+      static const llvm::Regex StdRegex("\\$std"), SimdRegex("\\$simd");
+      diag(Call->getExprLoc(), "'%0' can be replaced by %1")
+          << Old
+          << SimdRegex.sub(SmallString<32>({Std, "::simd"}),
+                           StdRegex.sub(Std, New));
     } else {
-      Message = (Twine("'") + Old + "' is a non-portable " +
-                 llvm::Triple::getArchTypeName(Arch) + " intrinsic function")
-                    .str();
+      diag("'%0' is a non-portable %1 intrinsic function")
+          << Old << llvm::Triple::getArchTypeName(Arch);
     }
-    diag(Call->getExprLoc(), Message);
   }
 }
 
diff --git a/clang-tools-extra/clang-tidy/readability/QualifiedAutoCheck.cpp b/clang-tools-extra/clang-tidy/readability/QualifiedAutoCheck.cpp
index 9ca4d2e1ad4deb..f2838cd0b98414 100644
--- a/clang-tools-extra/clang-tidy/readability/QualifiedAutoCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/QualifiedAutoCheck.cpp
@@ -209,10 +209,11 @@ void QualifiedAutoCheck::check(const MatchFinder::MatchResult &Result) {
     }();
 
     DiagnosticBuilder Diag =
-        diag(FixitLoc, "'%0%1%2auto %3' can be declared as '%4%3'")
-        << (IsLocalConst ? "const " : "")
-        << (IsLocalVolatile ? "volatile " : "")
-        << (IsLocalRestrict ? "__restrict " : "") << Var->getName() << ReplStr;
+        diag(FixitLoc,
+             "'%select{|const }0%select{|volatile }1%select{|__restrict }2auto "
+             "%3' can be declared as '%4%3'")
+        << IsLocalConst << IsLocalVolatile << IsLocalRestrict << Var->getName()
+        << ReplStr;
 
     for (SourceRange &Range : RemoveQualifiersRange) {
       Diag << FixItHint::CreateRemoval(CharSourceRange::getCharRange(Range));
@@ -253,10 +254,12 @@ void QualifiedAutoCheck::check(const MatchFinder::MatchResult &Result) {
           TypeSpec->getEnd().isMacroID())
         return;
       SourceLocation InsertPos = TypeSpec->getBegin();
-      diag(InsertPos, "'auto *%0%1%2' can be declared as 'const auto *%0%1%2'")
-          << (Var->getType().isLocalConstQualified() ? "const " : "")
-          << (Var->getType().isLocalVolatileQualified() ? "volatile " : "")
-          << Var->getName() << FixItHint::CreateInsertion(InsertPos, "const ");
+      diag(InsertPos,
+           "'auto *%select{|const }0%select{|volatile }1%2' can be declared as "
+           "'const auto *%select{|const }0%select{|volatile }1%2'")
+          << Var->getType().isLocalConstQualified()
+          << Var->getType().isLocalVolatileQualified() << Var->getName()
+          << FixItHint::CreateInsertion(InsertPos, "const ");
     }
     return;
   }
diff --git a/clang-tools-extra/clang-tidy/readability/UseAnyOfAllOfCheck.cpp b/clang-tools-extra/clang-tidy/readability/UseAnyOfAllOfCheck.cpp
index 6e837509708b09..495b2fa0b185f7 100644
--- a/clang-tools-extra/clang-tidy/readability/UseAnyOfAllOfCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/UseAnyOfAllOfCheck.cpp
@@ -88,19 +88,20 @@ static bool isViableLoop(const CXXForRangeStmt &S, ASTContext &Context) {
 }
 
 void UseAnyOfAllOfCheck::check(const MatchFinder::MatchResult &Result) {
-  StringRef Ranges = getLangOpts().CPlusPlus20 ? "::ranges" : "";
 
   if (const auto *S = Result.Nodes.getNodeAs<CXXForRangeStmt>("any_of_loop")) {
     if (!isViableLoop(*S, *Result.Context))
       return;
 
-    diag(S->getForLoc(), "replace loop by 'std%0::any_of()'") << Ranges;
+    diag(S->getForLoc(), "replace loop by 'std%select{|::ranges}0::any_of()'")
+        << getLangOpts().CPlusPlus20;
   } else if (const auto *S =
                  Result.Nodes.getNodeAs<CXXForRangeStmt>("all_of_loop")) {
     if (!isViableLoop(*S, *Result.Context))
       return;
 
-    diag(S->getForLoc(), "replace loop by 'std%0::all_of()'") << Ranges;
+    diag(S->getForLoc(), "replace loop by 'std%select{|::ranges}0::all_of()'")
+        << getLangOpts().CPlusPlus20;
   }
 }
 
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc-uniqueptr-reset-release.cpp b/clang-tools-extra/test/clang-tidy/checkers/misc-uniqueptr-reset-release.cpp
index 1bd6e6f4c5475e..c97b9b3f4a968c 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/misc-uniqueptr-reset-release.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc-uniqueptr-reset-release.cpp
@@ -33,27 +33,27 @@ void f() {
   std::unique_ptr<Foo> *y = &b;
 
   a.reset(b.release());
-  // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: prefer ptr1 = std::move(ptr2) over ptr1.reset(ptr2.release()) [misc-uniqueptr-reset-release]
+  // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: prefer ptr = std::move(ptr2) over ptr.reset(ptr2.release()) [misc-uniqueptr-reset-release]
   // CHECK-FIXES: a = std::move(b);
   a.reset(c.release());
-  // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: prefer ptr1 = std::move(ptr2)
+  // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: prefer ptr = std::move(ptr2)
   // CHECK-FIXES: a = std::move(c);
   a.reset(Create().release());
   // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: prefer ptr = ReturnUnique() over ptr.reset(ReturnUnique().release()) [misc-uniqueptr-reset-release]
   // CHECK-FIXES: a = Create();
   x->reset(y->release());
-  // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: prefer ptr1 = std::move(ptr2)
+  // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: prefer ptr = std::move(ptr2)
   // CHECK-FIXES: *x = std::move(*y);
   Look().reset(Look().release());
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: prefer ptr1 = std::move(ptr2)
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: prefer ptr = std::move(ptr2)
   // CHECK-FIXES: Look() = std::move(Look());
   Get()->reset(Get()->release());
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: prefer ptr1 = std::move(ptr2)
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: prefer ptr = std::move(ptr2)
   // CHECK-FIXES: *Get() = std::move(*Get());
 
   std::unique_ptr<Bar, FooFunc> func_a, func_b;
   func_a.reset(func_b.release());
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: prefer ptr1 = std::move(ptr2)
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: prefer ptr = std::move(ptr2)
   // CHECK-FIXES: func_a = std::move(func_b);
 }