[clang-tidy] White List Option for performance-unnecessary-value-param, performance-unnecessary-copy-initialization and performance-for-range-copy

New option added to these three checks to be able to silence false positives on
types that are intentionally passed by value or copied. Such types are e.g.
intrusive reference counting pointer types like llvm::IntrusiveRefCntPtr. The
new option is named WhiteListTypes and can contain a semicolon-separated list of
names of these types. Regular expressions are allowed. Default is empty.

Differential Revision: https://reviews.llvm.org/D52727

llvm-svn: 344340

13 files changed, 378 insertions, 11 deletions

diff --git a/clang-tools-extra/clang-tidy/performance/ForRangeCopyCheck.cpp b/clang-tools-extra/clang-tidy/performance/ForRangeCopyCheck.cpp
index d60a2f349f6..4b90df43aed 100644
--- a/clang-tools-extra/clang-tidy/performance/ForRangeCopyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/ForRangeCopyCheck.cpp
@@ -10,6 +10,8 @@
 #include "ForRangeCopyCheck.h"
 #include "../utils/DeclRefExprUtils.h"
 #include "../utils/FixItHintUtils.h"
+#include "../utils/Matchers.h"
+#include "../utils/OptionsUtils.h"
 #include "../utils/TypeTraits.h"
 #include "clang/Analysis/Analyses/ExprMutationAnalyzer.h"
 
@@ -21,10 +23,14 @@ namespace performance {
 
 ForRangeCopyCheck::ForRangeCopyCheck(StringRef Name, ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      WarnOnAllAutoCopies(Options.get("WarnOnAllAutoCopies", 0)) {}
+      WarnOnAllAutoCopies(Options.get("WarnOnAllAutoCopies", 0)),
+      AllowedTypes(
+          utils::options::parseStringList(Options.get("AllowedTypes", ""))) {}
 
 void ForRangeCopyCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "WarnOnAllAutoCopies", WarnOnAllAutoCopies);
+  Options.store(Opts, "AllowedTypes",
+                utils::options::serializeStringList(AllowedTypes));
 }
 
 void ForRangeCopyCheck::registerMatchers(MatchFinder *Finder) {
@@ -32,7 +38,10 @@ void ForRangeCopyCheck::registerMatchers(MatchFinder *Finder) {
   // initialized through MaterializeTemporaryExpr which indicates a type
   // conversion.
   auto LoopVar = varDecl(
-      hasType(hasCanonicalType(unless(anyOf(referenceType(), pointerType())))),
+      hasType(qualType(
+          unless(anyOf(hasCanonicalType(anyOf(referenceType(), pointerType())),
+                       hasDeclaration(namedDecl(
+                           matchers::matchesAnyListedName(AllowedTypes))))))),
       unless(hasInitializer(expr(hasDescendant(materializeTemporaryExpr())))));
   Finder->addMatcher(cxxForRangeStmt(hasLoopVariable(LoopVar.bind("loopVar")))
                          .bind("forRange"),
@@ -41,6 +50,7 @@ void ForRangeCopyCheck::registerMatchers(MatchFinder *Finder) {
 
 void ForRangeCopyCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *Var = Result.Nodes.getNodeAs<VarDecl>("loopVar");
+
   // Ignore code in macros since we can't place the fixes correctly.
   if (Var->getBeginLoc().isMacroID())
     return;
diff --git a/clang-tools-extra/clang-tidy/performance/ForRangeCopyCheck.h b/clang-tools-extra/clang-tidy/performance/ForRangeCopyCheck.h
index f88a126e5d7..de8b2c911db 100644
--- a/clang-tools-extra/clang-tidy/performance/ForRangeCopyCheck.h
+++ b/clang-tools-extra/clang-tidy/performance/ForRangeCopyCheck.h
@@ -40,6 +40,7 @@ private:
                                        ASTContext &Context);
 
   const bool WarnOnAllAutoCopies;
+  const std::vector<std::string> AllowedTypes;
 };
 
 } // namespace performance
diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp
index 177497c41b8..ef6bcd6f649 100644
--- a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp
+++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp
@@ -12,6 +12,7 @@
 #include "../utils/DeclRefExprUtils.h"
 #include "../utils/FixItHintUtils.h"
 #include "../utils/Matchers.h"
+#include "../utils/OptionsUtils.h"
 
 namespace clang {
 namespace tidy {
@@ -30,6 +31,12 @@ void recordFixes(const VarDecl &Var, ASTContext &Context,
 using namespace ::clang::ast_matchers;
 using utils::decl_ref_expr::isOnlyUsedAsConst;
 
+UnnecessaryCopyInitialization::UnnecessaryCopyInitialization(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      AllowedTypes(
+          utils::options::parseStringList(Options.get("AllowedTypes", ""))) {}
+
 void UnnecessaryCopyInitialization::registerMatchers(MatchFinder *Finder) {
   auto ConstReference = referenceType(pointee(qualType(isConstQualified())));
   auto ConstOrConstReference =
@@ -50,12 +57,17 @@ void UnnecessaryCopyInitialization::registerMatchers(MatchFinder *Finder) {
       callExpr(callee(functionDecl(returns(ConstReference))),
                unless(callee(cxxMethodDecl())));
 
-  auto localVarCopiedFrom = [](const internal::Matcher<Expr> &CopyCtorArg) {
+  auto localVarCopiedFrom = [this](const internal::Matcher<Expr> &CopyCtorArg) {
     return compoundStmt(
                forEachDescendant(
                    declStmt(
                        has(varDecl(hasLocalStorage(),
-                                   hasType(matchers::isExpensiveToCopy()),
+                                   hasType(qualType(
+                                       allOf(hasCanonicalType(
+                                                 matchers::isExpensiveToCopy()),
+                                             unless(hasDeclaration(namedDecl(
+                                                 matchers::matchesAnyListedName(
+                                                     AllowedTypes))))))),
                                    unless(isImplicit()),
                                    hasInitializer(
                                        cxxConstructExpr(
@@ -84,6 +96,7 @@ void UnnecessaryCopyInitialization::check(
   const auto *ObjectArg = Result.Nodes.getNodeAs<VarDecl>("objectArg");
   const auto *BlockStmt = Result.Nodes.getNodeAs<Stmt>("blockStmt");
   const auto *CtorCall = Result.Nodes.getNodeAs<CXXConstructExpr>("ctorCall");
+
   // Do not propose fixes if the DeclStmt has multiple VarDecls or in macros
   // since we cannot place them correctly.
   bool IssueFix =
@@ -144,6 +157,12 @@ void UnnecessaryCopyInitialization::handleCopyFromLocalVar(
     recordFixes(NewVar, Context, Diagnostic);
 }
 
+void UnnecessaryCopyInitialization::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "AllowedTypes",
+                utils::options::serializeStringList(AllowedTypes));
+}
+
 } // namespace performance
 } // namespace tidy
 } // namespace clang
diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.h b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.h
index 8ed4142731c..1844aa4bf29 100644
--- a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.h
+++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.h
@@ -26,10 +26,10 @@ namespace performance {
 // const references, and const pointers to const.
 class UnnecessaryCopyInitialization : public ClangTidyCheck {
 public:
-  UnnecessaryCopyInitialization(StringRef Name, ClangTidyContext *Context)
-      : ClangTidyCheck(Name, Context) {}
+  UnnecessaryCopyInitialization(StringRef Name, ClangTidyContext *Context);
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
 
 private:
   void handleCopyFromMethodReturn(const VarDecl &Var, const Stmt &BlockStmt,
@@ -38,6 +38,7 @@ private:
   void handleCopyFromLocalVar(const VarDecl &NewVar, const VarDecl &OldVar,
                               const Stmt &BlockStmt, bool IssueFix,
                               ASTContext &Context);
+  const std::vector<std::string> AllowedTypes;
 };
 
 } // namespace performance
diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
index db5a12f9b12..ac76cea3603 100644
--- a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
@@ -12,6 +12,7 @@
 #include "../utils/DeclRefExprUtils.h"
 #include "../utils/FixItHintUtils.h"
 #include "../utils/Matchers.h"
+#include "../utils/OptionsUtils.h"
 #include "../utils/TypeTraits.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Lex/Lexer.h"
@@ -68,17 +69,22 @@ UnnecessaryValueParamCheck::UnnecessaryValueParamCheck(
     StringRef Name, ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
       IncludeStyle(utils::IncludeSorter::parseIncludeStyle(
-          Options.getLocalOrGlobal("IncludeStyle", "llvm"))) {}
+          Options.getLocalOrGlobal("IncludeStyle", "llvm"))),
+      AllowedTypes(
+          utils::options::parseStringList(Options.get("AllowedTypes", ""))) {}
 
 void UnnecessaryValueParamCheck::registerMatchers(MatchFinder *Finder) {
   // This check is specific to C++ and doesn't apply to languages like
   // Objective-C.
   if (!getLangOpts().CPlusPlus)
     return;
-  const auto ExpensiveValueParamDecl =
-      parmVarDecl(hasType(hasCanonicalType(allOf(
-                      unless(referenceType()), matchers::isExpensiveToCopy()))),
-                  decl().bind("param"));
+  const auto ExpensiveValueParamDecl = parmVarDecl(
+      hasType(qualType(allOf(
+          hasCanonicalType(matchers::isExpensiveToCopy()),
+          unless(anyOf(hasCanonicalType(referenceType()),
+                       hasDeclaration(namedDecl(
+                           matchers::matchesAnyListedName(AllowedTypes)))))))),
+      decl().bind("param"));
   Finder->addMatcher(
       functionDecl(hasBody(stmt()), isDefinition(), unless(isImplicit()),
                    unless(cxxMethodDecl(anyOf(isOverride(), isFinal()))),
@@ -173,6 +179,8 @@ void UnnecessaryValueParamCheck::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "IncludeStyle",
                 utils::IncludeSorter::toString(IncludeStyle));
+  Options.store(Opts, "AllowedTypes",
+                utils::options::serializeStringList(AllowedTypes));
 }
 
 void UnnecessaryValueParamCheck::onEndOfTranslationUnit() {
diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.h b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.h
index ae5ef7e9631..a1d6586931e 100644
--- a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.h
+++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.h
@@ -40,6 +40,7 @@ private:
       MutationAnalyzers;
   std::unique_ptr<utils::IncludeInserter> Inserter;
   const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  const std::vector<std::string> AllowedTypes;
 };
 
 } // namespace performance
diff --git a/clang-tools-extra/clang-tidy/utils/Matchers.h b/clang-tools-extra/clang-tidy/utils/Matchers.h
index aeb639fafa5..849b36fb763 100644
--- a/clang-tools-extra/clang-tidy/utils/Matchers.h
+++ b/clang-tools-extra/clang-tidy/utils/Matchers.h
@@ -48,6 +48,13 @@ AST_MATCHER_FUNCTION(ast_matchers::TypeMatcher, isReferenceToConst) {
   return referenceType(pointee(qualType(isConstQualified())));
 }
 
+AST_MATCHER_P(NamedDecl, matchesAnyListedName, std::vector<std::string>,
+              NameList) {
+  return llvm::any_of(NameList, [&Node](const std::string &Name) {
+      return llvm::Regex(Name).match(Node.getName());
+    });
+}
+
 } // namespace matchers
 } // namespace tidy
 } // namespace clang
diff --git a/clang-tools-extra/docs/clang-tidy/checks/performance-for-range-copy.rst b/clang-tools-extra/docs/clang-tidy/checks/performance-for-range-copy.rst
index 2e7db98d873..35747271c90 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/performance-for-range-copy.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/performance-for-range-copy.rst
@@ -25,3 +25,10 @@ Options
 
    When non-zero, warns on any use of `auto` as the type of the range-based for
    loop variable. Default is `0`.
+
+.. option:: AllowedTypes
+
+   A semicolon-separated list of names of types allowed to be copied in each
+   iteration. Regular expressions are accepted, e.g. `[Rr]ef(erence)?$` matches
+   every type with suffix `Ref`, `ref`, `Reference` and `reference`. The default
+   is empty.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/performance-unnecessary-copy-initialization.rst b/clang-tools-extra/docs/clang-tidy/checks/performance-unnecessary-copy-initialization.rst
index 2bd77551a38..661c3072e47 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/performance-unnecessary-copy-initialization.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/performance-unnecessary-copy-initialization.rst
@@ -35,3 +35,13 @@ Example:
     string UnnecessaryCopy2 = UnnecessaryCopy1;
     UnnecessaryCopy2.find("bar");
   }
+
+Options
+-------
+
+.. option:: AllowedTypes
+
+   A semicolon-separated list of names of types allowed to be initialized by
+   copying. Regular expressions are accepted, e.g. `[Rr]ef(erence)?$` matches
+   every type with suffix `Ref`, `ref`, `Reference` and `reference`. The
+   default is empty.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/performance-unnecessary-value-param.rst b/clang-tools-extra/docs/clang-tidy/checks/performance-unnecessary-value-param.rst
index e69610ecfdc..21a5c65f6d5 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/performance-unnecessary-value-param.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/performance-unnecessary-value-param.rst
@@ -61,3 +61,9 @@ Options
 
    A string specifying which include-style is used, `llvm` or `google`. Default
    is `llvm`.
+
+.. option:: AllowedTypes
+
+   A semicolon-separated list of names of types allowed to be passed by value.
+   Regular expressions are accepted, e.g. `[Rr]ef(erence)?$` matches every type
+   with suffix `Ref`, `ref`, `Reference` and `reference`. The default is empty.
diff --git a/clang-tools-extra/test/clang-tidy/performance-for-range-copy-allowed-types.cpp b/clang-tools-extra/test/clang-tidy/performance-for-range-copy-allowed-types.cpp
new file mode 100644
index 00000000000..a3e7a6bf2c9
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/performance-for-range-copy-allowed-types.cpp
@@ -0,0 +1,124 @@
+// RUN: %check_clang_tidy %s performance-for-range-copy %t -- -config="{CheckOptions: [{key: performance-for-range-copy.AllowedTypes, value: '[Pp]ointer$;[Pp]tr$;[Rr]ef(erence)?$'}]}" -- -std=c++11 -fno-delayed-template-parsing
+
+template <typename T>
+struct Iterator {
+  void operator++() {}
+  const T& operator*() {
+    static T* TT = new T();
+    return *TT;
+  }
+  bool operator!=(const Iterator &) { return false; }
+  typedef const T& const_reference;
+};
+template <typename T>
+struct View {
+  T begin() { return T(); }
+  T begin() const { return T(); }
+  T end() { return T(); }
+  T end() const { return T(); }
+  typedef typename T::const_reference const_reference;
+};
+
+struct SmartPointer {
+  ~SmartPointer();
+};
+
+struct smart_pointer {
+  ~smart_pointer();
+};
+
+struct SmartPtr {
+  ~SmartPtr();
+};
+
+struct smart_ptr {
+  ~smart_ptr();
+};
+
+struct SmartReference {
+  ~SmartReference();
+};
+
+struct smart_reference {
+  ~smart_reference();
+};
+
+struct SmartRef {
+  ~SmartRef();
+};
+
+struct smart_ref {
+  ~smart_ref();
+};
+
+struct OtherType {
+  ~OtherType();
+};
+
+template <typename T> struct SomeComplexTemplate {
+  ~SomeComplexTemplate();
+};
+
+typedef SomeComplexTemplate<int> NotTooComplexRef;
+
+void negativeSmartPointer() {
+  for (auto P : View<Iterator<SmartPointer>>()) {
+    auto P2 = P;
+  }
+}
+
+void negative_smart_pointer() {
+  for (auto p : View<Iterator<smart_pointer>>()) {
+    auto p2 = p;
+  }
+}
+
+void negativeSmartPtr() {
+  for (auto P : View<Iterator<SmartPtr>>()) {
+    auto P2 = P;
+  }
+}
+
+void negative_smart_ptr() {
+  for (auto p : View<Iterator<smart_ptr>>()) {
+    auto p2 = p;
+  }
+}
+
+void negativeSmartReference() {
+  for (auto R : View<Iterator<SmartReference>>()) {
+    auto R2 = R;
+  }
+}
+
+void negative_smart_reference() {
+  for (auto r : View<Iterator<smart_reference>>()) {
+    auto r2 = r;
+  }
+}
+
+void negativeSmartRef() {
+  for (auto R : View<Iterator<SmartRef>>()) {
+    auto R2 = R;
+  }
+}
+
+void negative_smart_ref() {
+  for (auto r : View<Iterator<smart_ref>>()) {
+    auto r2 = r;
+  }
+}
+
+void positiveOtherType() {
+  for (auto O : View<Iterator<OtherType>>()) {
+  // CHECK-MESSAGES: [[@LINE-1]]:13: warning: loop variable is copied but only used as const reference; consider making it a const reference [performance-for-range-copy]
+  // CHECK-FIXES: for (const auto& O : View<Iterator<OtherType>>()) {
+    auto O2 = O;
+  }
+}
+
+void negativeNotTooComplexRef() {
+  for (NotTooComplexRef R : View<Iterator<NotTooComplexRef>>()) {
+    auto R2 = R;
+  }
+}
diff --git a/clang-tools-extra/test/clang-tidy/performance-unnecessary-copy-initialization-allowed-types.cpp b/clang-tools-extra/test/clang-tidy/performance-unnecessary-copy-initialization-allowed-types.cpp
new file mode 100644
index 00000000000..420efa8dbe3
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/performance-unnecessary-copy-initialization-allowed-types.cpp
@@ -0,0 +1,98 @@
+// RUN: %check_clang_tidy %s performance-unnecessary-copy-initialization %t -- -config="{CheckOptions: [{key: performance-unnecessary-copy-initialization.AllowedTypes, value: '[Pp]ointer$;[Pp]tr$;[Rr]ef(erence)?$'}]}" --
+
+struct SmartPointer {
+  ~SmartPointer();
+};
+
+struct smart_pointer {
+  ~smart_pointer();
+};
+
+struct SmartPtr {
+  ~SmartPtr();
+};
+
+struct smart_ptr {
+  ~smart_ptr();
+};
+
+struct SmartReference {
+  ~SmartReference();
+};
+
+struct smart_reference {
+  ~smart_reference();
+};
+
+struct SmartRef {
+  ~SmartRef();
+};
+
+struct smart_ref {
+  ~smart_ref();
+};
+
+struct OtherType {
+  ~OtherType();
+};
+
+template <typename T> struct SomeComplexTemplate {
+  ~SomeComplexTemplate();
+};
+
+typedef SomeComplexTemplate<int> NotTooComplexRef;
+
+const SmartPointer &getSmartPointer();
+const smart_pointer &get_smart_pointer();
+const SmartPtr &getSmartPtr();
+const smart_ptr &get_smart_ptr();
+const SmartReference &getSmartReference();
+const smart_reference &get_smart_reference();
+const SmartRef &getSmartRef();
+const smart_ref &get_smart_ref();
+const OtherType &getOtherType();
+const NotTooComplexRef &getNotTooComplexRef();
+
+void negativeSmartPointer() {
+  const auto P = getSmartPointer();
+}
+
+void negative_smart_pointer() {
+  const auto p = get_smart_pointer();
+}
+
+void negativeSmartPtr() {
+  const auto P = getSmartPtr();
+}
+
+void negative_smart_ptr() {
+  const auto p = get_smart_ptr();
+}
+
+void negativeSmartReference() {
+  const auto R = getSmartReference();
+}
+
+void negative_smart_reference() {
+  const auto r = get_smart_reference();
+}
+
+void negativeSmartRef() {
+  const auto R = getSmartRef();
+}
+
+void negative_smart_ref() {
+  const auto r = get_smart_ref();
+}
+
+void positiveOtherType() {
+  const auto O = getOtherType();
+  // CHECK-MESSAGES: [[@LINE-1]]:14: warning: the const qualified variable 'O' is copy-constructed from a const reference; consider making it a const reference [performance-unnecessary-copy-initialization]
+  // CHECK-FIXES: const auto& O = getOtherType();
+}
+
+void negativeNotTooComplexRef() {
+  const NotTooComplexRef R = getNotTooComplexRef();
+  // Using `auto` here would result in the "canonical" type which does not match
+  // the pattern.
+}
diff --git a/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param-allowed-types.cpp b/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param-allowed-types.cpp
new file mode 100644
index 00000000000..054732cd99d
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param-allowed-types.cpp
@@ -0,0 +1,75 @@
+// RUN: %check_clang_tidy %s performance-unnecessary-value-param %t -- -config="{CheckOptions: [{key: performance-unnecessary-value-param.AllowedTypes, value: '[Pp]ointer$;[Pp]tr$;[Rr]ef(erence)?$'}]}" --
+
+struct SmartPointer {
+  ~SmartPointer();
+};
+
+struct smart_pointer {
+  ~smart_pointer();
+};
+
+struct SmartPtr {
+  ~SmartPtr();
+};
+
+struct smart_ptr {
+  ~smart_ptr();
+};
+
+struct SmartReference {
+  ~SmartReference();
+};
+
+struct smart_reference {
+  ~smart_reference();
+};
+
+struct SmartRef {
+  ~SmartRef();
+};
+
+struct smart_ref {
+  ~smart_ref();
+};
+
+struct OtherType {
+  ~OtherType();
+};
+
+template <typename T> struct SomeComplexTemplate {
+  ~SomeComplexTemplate();
+};
+
+typedef SomeComplexTemplate<int> NotTooComplexRef;
+
+void negativeSmartPointer(SmartPointer P) {
+}
+
+void negative_smart_pointer(smart_pointer p) {
+}
+
+void negativeSmartPtr(SmartPtr P) {
+}
+
+void negative_smart_ptr(smart_ptr p) {
+}
+
+void negativeSmartReference(SmartReference R) {
+}
+
+void negative_smart_reference(smart_reference r) {
+}
+
+void negativeSmartRef(SmartRef R) {
+}
+
+void negative_smart_ref(smart_ref r) {
+}
+
+void positiveOtherType(OtherType O) {
+  // CHECK-MESSAGES: [[@LINE-1]]:34: warning: the parameter 'O' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param]
+  // CHECK-FIXES: void positiveOtherType(const OtherType& O) {
+}
+
+void negativeNotTooComplexRef(NotTooComplexRef R) {
+}