diff --git a/clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.h b/clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.h
--- a/clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.h
+++ b/clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.h
@@ -25,7 +25,7 @@
   DefaultOperatorNewAlignmentCheck(StringRef Name, ClangTidyContext *Context)
       : ClangTidyCheck(Name, Context) {}
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    return !LangOpts.CPlusPlus17;
+    return LangOpts.CPlusPlus && !LangOpts.CPlusPlus17;
   }
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
diff --git a/clang-tools-extra/clang-tidy/google/ExplicitConstructorCheck.cpp b/clang-tools-extra/clang-tidy/google/ExplicitConstructorCheck.cpp
--- a/clang-tools-extra/clang-tidy/google/ExplicitConstructorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/google/ExplicitConstructorCheck.cpp
@@ -24,6 +24,8 @@
                                       isDeleted(), isInstantiated())))
           .bind("ctor"),
       this);
+  if (!getLangOpts().CPlusPlus11)
+    return;
   Finder->addMatcher(
       cxxConversionDecl(unless(anyOf(isExplicit(), // Already marked explicit.
                                      isImplicit(), // Compiler-generated.
diff --git a/clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.h b/clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.h
--- a/clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.h
@@ -20,7 +20,7 @@
 public:
   LoopConvertCheck(StringRef Name, ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    return LangOpts.CPlusPlus;
+    return LangOpts.CPlusPlus11;
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
diff --git a/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h b/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h
--- a/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h
@@ -44,7 +44,7 @@
 public:
   ReplaceAutoPtrCheck(StringRef Name, ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    return LangOpts.CPlusPlus;
+    return LangOpts.CPlusPlus11;
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
diff --git a/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h b/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h
--- a/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h
@@ -19,7 +19,7 @@
 public:
   UseAutoCheck(StringRef Name, ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    return LangOpts.CPlusPlus;
+    return LangOpts.CPlusPlus11;
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
diff --git a/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.h b/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.h
--- a/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseEqualsDefaultCheck.h
@@ -38,7 +38,7 @@
 public:
   UseEqualsDefaultCheck(StringRef Name, ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    return LangOpts.CPlusPlus;
+    return LangOpts.CPlusPlus11;
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
diff --git a/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
--- a/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
@@ -40,7 +40,7 @@
       : ClangTidyCheck(Name, Context),
         IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", 1) != 0) {}
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    return LangOpts.CPlusPlus;
+    return LangOpts.CPlusPlus11;
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
diff --git a/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
--- a/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
@@ -19,9 +19,7 @@
 public:
   UseNullptrCheck(StringRef Name, ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    // FIXME this should be CPlusCplus11 but that causes test cases to
-    // erroneously fail.
-    return LangOpts.CPlusPlus;
+    return LangOpts.CPlusPlus11;
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
diff --git a/clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.h b/clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.h
--- a/clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.h
+++ b/clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.h
@@ -28,7 +28,7 @@
         CheckTriviallyCopyableMove(
             Options.get("CheckTriviallyCopyableMove", true)) {}
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    return LangOpts.CPlusPlus;
+    return LangOpts.CPlusPlus11;
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize-use-nullptr-basic.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize-use-nullptr-basic.cpp
deleted file mode 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize-use-nullptr-basic.cpp
+++ /dev/null
@@ -1,362 +0,0 @@
-// RUN: %check_clang_tidy -std=c++98 %s modernize-use-nullptr %t -- -- -Wno-non-literal-null-conversion
-//
-// Some parts of the test (e.g. assignment of `const int` to `int *`) fail in
-// C++11, so we need to run the test in C++98 mode.
-//
-// FIXME: Make the test work in all language modes.
-
-const unsigned int g_null = 0;
-#define NULL 0
-
-void test_assignment() {
-  int *p1 = 0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr [modernize-use-nullptr]
-  // CHECK-FIXES: int *p1 = nullptr;
-  p1 = 0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: use nullptr
-  // CHECK-FIXES: p1 = nullptr;
-
-  int *p2 = NULL;
-  // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr
-  // CHECK-FIXES: int *p2 = nullptr;
-
-  p2 = p1;
-  // CHECK-FIXES: p2 = p1;
-
-  const int null = 0;
-  int *p3 = null;
-  // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr
-  // CHECK-FIXES: int *p3 = nullptr;
-
-  p3 = NULL;
-  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: use nullptr
-  // CHECK-FIXES: p3 = nullptr;
-
-  int *p4 = p3;
-  // CHECK-FIXES: int *p4 = p3;
-
-  p4 = null;
-  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: use nullptr
-  // CHECK-FIXES: p4 = nullptr;
-
-  int i1 = 0;
-
-  int i2 = NULL;
-
-  int i3 = null;
-
-  int *p5, *p6, *p7;
-  p5 = p6 = p7 = NULL;
-  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: use nullptr
-  // CHECK-FIXES: p5 = p6 = p7 = nullptr;
-}
-
-struct Foo {
-  Foo(int *p = NULL) : m_p1(p) {}
-  // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: use nullptr
-  // CHECK-FIXES: Foo(int *p = nullptr) : m_p1(p) {}
-
-  void bar(int *p = 0) {}
-  // CHECK-MESSAGES: :[[@LINE-1]]:21: warning: use nullptr
-  // CHECK-FIXES: void bar(int *p = nullptr) {}
-
-  void baz(int i = 0) {}
-
-  int *m_p1;
-  static int *m_p2;
-};
-
-int *Foo::m_p2 = NULL;
-// CHECK-MESSAGES: :[[@LINE-1]]:18: warning: use nullptr
-// CHECK-FIXES: int *Foo::m_p2 = nullptr;
-
-template <typename T>
-struct Bar {
-  Bar(T *p) : m_p(p) {
-    m_p = static_cast<T*>(NULL);
-    // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: use nullptr
-    // CHECK-FIXES: m_p = static_cast<T*>(nullptr);
-
-    m_p = static_cast<T*>(reinterpret_cast<int*>((void*)NULL));
-    // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: use nullptr
-    // CHECK-FIXES: m_p = static_cast<T*>(nullptr);
-
-    m_p = static_cast<T*>(p ? p : static_cast<void*>(g_null));
-    // CHECK-MESSAGES: :[[@LINE-1]]:54: warning: use nullptr
-    // CHECK-FIXES: m_p = static_cast<T*>(p ? p : static_cast<void*>(nullptr));
-
-    T *p2 = static_cast<T*>(reinterpret_cast<int*>((void*)NULL));
-    // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: use nullptr
-    // CHECK-FIXES: T *p2 = static_cast<T*>(nullptr);
-
-    m_p = NULL;
-    // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: use nullptr
-    // CHECK-FIXES: m_p = nullptr;
-
-    int i = static_cast<int>(0.f);
-    T *i2 = static_cast<int>(0.f);
-    // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr
-    // CHECK-FIXES: T *i2 = nullptr;
-  }
-
-  T *m_p;
-};
-
-struct Baz {
-  Baz() : i(0) {}
-  int i;
-};
-
-void test_cxx_cases() {
-  Foo f(g_null);
-  // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use nullptr
-  // CHECK-FIXES: Foo f(nullptr);
-
-  f.bar(NULL);
-  // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use nullptr
-  // CHECK-FIXES: f.bar(nullptr);
-
-  f.baz(g_null);
-
-  f.m_p1 = 0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: use nullptr
-  // CHECK-FIXES: f.m_p1 = nullptr;
-
-  Bar<int> b(g_null);
-  // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: use nullptr
-  // CHECK-FIXES: Bar<int> b(nullptr);
-
-  Baz b2;
-  int Baz::*memptr(0);
-  // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: use nullptr
-  // CHECK-FIXES: int Baz::*memptr(nullptr);
-
-  memptr = 0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: use nullptr
-  // CHECK-FIXES: memptr = nullptr;
-}
-
-void test_function_default_param1(void *p = 0);
-// CHECK-MESSAGES: :[[@LINE-1]]:45: warning: use nullptr
-// CHECK-FIXES: void test_function_default_param1(void *p = nullptr);
-
-void test_function_default_param2(void *p = NULL);
-// CHECK-MESSAGES: :[[@LINE-1]]:45: warning: use nullptr
-// CHECK-FIXES: void test_function_default_param2(void *p = nullptr);
-
-void test_function_default_param3(void *p = g_null);
-// CHECK-MESSAGES: :[[@LINE-1]]:45: warning: use nullptr
-// CHECK-FIXES: void test_function_default_param3(void *p = nullptr);
-
-void test_function(int *p) {}
-
-void test_function_no_ptr_param(int i) {}
-
-void test_function_call() {
-  test_function(0);
-  // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: use nullptr
-  // CHECK-FIXES: test_function(nullptr);
-
-  test_function(NULL);
-  // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: use nullptr
-  // CHECK-FIXES: test_function(nullptr);
-
-  test_function(g_null);
-  // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: use nullptr
-  // CHECK-FIXES: test_function(nullptr);
-
-  test_function_no_ptr_param(0);
-}
-
-char *test_function_return1() {
-  return 0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use nullptr
-  // CHECK-FIXES: return nullptr;
-}
-
-void *test_function_return2() {
-  return NULL;
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use nullptr
-  // CHECK-FIXES: return nullptr;
-}
-
-long *test_function_return3() {
-  return g_null;
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use nullptr
-  // CHECK-FIXES: return nullptr;
-}
-
-int test_function_return4() {
-  return 0;
-}
-
-int test_function_return5() {
-  return NULL;
-}
-
-int test_function_return6() {
-  return g_null;
-}
-
-int *test_function_return_cast1() {
-  return(int)0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use nullptr
-  // CHECK-FIXES: return nullptr;
-}
-
-int *test_function_return_cast2() {
-#define RET return
-  RET(int)0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: use nullptr
-  // CHECK-FIXES: RET nullptr;
-#undef RET
-}
-
-// Test parentheses expressions resulting in a nullptr.
-int *test_parentheses_expression1() {
-  return(0);
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use nullptr
-  // CHECK-FIXES: return(nullptr);
-}
-
-int *test_parentheses_expression2() {
-  return(int(0.f));
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use nullptr
-  // CHECK-FIXES: return(nullptr);
-}
-
-int *test_nested_parentheses_expression() {
-  return((((0))));
-  // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr
-  // CHECK-FIXES: return((((nullptr))));
-}
-
-void *test_parentheses_explicit_cast() {
-  return(static_cast<void*>(0));
-  // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: use nullptr
-  // CHECK-FIXES: return(static_cast<void*>(nullptr));
-}
-
-void *test_parentheses_explicit_cast_sequence1() {
-  return(static_cast<void*>(static_cast<int*>((void*)NULL)));
-  // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: use nullptr
-  // CHECK-FIXES: return(static_cast<void*>(nullptr));
-}
-
-void *test_parentheses_explicit_cast_sequence2() {
-  return(static_cast<void*>(reinterpret_cast<int*>((float*)int(0.f))));
-  // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: use nullptr
-  // CHECK-FIXES: return(static_cast<void*>(nullptr));
-}
-
-// Test explicit cast expressions resulting in nullptr.
-struct Bam {
-  Bam(int *a) {}
-  Bam(float *a) {}
-  Bam operator=(int *a) { return Bam(a); }
-  Bam operator=(float *a) { return Bam(a); }
-};
-
-void ambiguous_function(int *a) {}
-void ambiguous_function(float *a) {}
-void const_ambiguous_function(const int *p) {}
-void const_ambiguous_function(const float *p) {}
-
-void test_explicit_cast_ambiguous1() {
-  ambiguous_function((int*)0);
-  // CHECK-MESSAGES: :[[@LINE-1]]:28: warning: use nullptr
-  // CHECK-FIXES: ambiguous_function((int*)nullptr);
-}
-
-void test_explicit_cast_ambiguous2() {
-  ambiguous_function((int*)(0));
-  // CHECK-MESSAGES: :[[@LINE-1]]:28: warning: use nullptr
-  // CHECK-FIXES: ambiguous_function((int*)nullptr);
-}
-
-void test_explicit_cast_ambiguous3() {
-  ambiguous_function(static_cast<int*>(reinterpret_cast<int*>((float*)0)));
-  // CHECK-MESSAGES: :[[@LINE-1]]:40: warning: use nullptr
-  // CHECK-FIXES: ambiguous_function(static_cast<int*>(nullptr));
-}
-
-Bam test_explicit_cast_ambiguous4() {
-  return(((int*)(0)));
-  // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: use nullptr
-  // CHECK-FIXES: return(((int*)nullptr));
-}
-
-void test_explicit_cast_ambiguous5() {
-  // Test for ambiguous overloaded constructors.
-  Bam k((int*)(0));
-  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: use nullptr
-  // CHECK-FIXES: Bam k((int*)nullptr);
-
-  // Test for ambiguous overloaded operators.
-  k = (int*)0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr
-  // CHECK-FIXES: k = (int*)nullptr;
-}
-
-void test_const_pointers_abiguous() {
-  const_ambiguous_function((int*)0);
-  // CHECK-MESSAGES: :[[@LINE-1]]:34: warning: use nullptr
-  // CHECK-FIXES: const_ambiguous_function((int*)nullptr);
-}
-
-// Test where the implicit cast to null is surrounded by another implicit cast
-// with possible explicit casts in-between.
-void test_const_pointers() {
-  const int *const_p1 = 0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: use nullptr
-  // CHECK-FIXES: const int *const_p1 = nullptr;
-  const int *const_p2 = NULL;
-  // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: use nullptr
-  // CHECK-FIXES: const int *const_p2 = nullptr;
-  const int *const_p3 = (int)0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: use nullptr
-  // CHECK-FIXES: const int *const_p3 = nullptr;
-  const int *const_p4 = (int)0.0f;
-  // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: use nullptr
-  // CHECK-FIXES: const int *const_p4 = nullptr;
-  const int *const_p5 = (int*)0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: use nullptr
-  // CHECK-FIXES: const int *const_p5 = (int*)nullptr;
-  int *t;
-  const int *const_p6 = static_cast<int*>(t ? t : static_cast<int*>(0));
-  // CHECK-MESSAGES: :[[@LINE-1]]:69: warning: use nullptr
-  // CHECK-FIXES: const int *const_p6 = static_cast<int*>(t ? t : static_cast<int*>(nullptr));
-}
-
-void test_nested_implicit_cast_expr() {
-  int func0(void*, void*);
-  int func1(int, void*, void*);
-
-  (double)func1(0, 0, 0);
-  // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: use nullptr
-  // CHECK-MESSAGES: :[[@LINE-2]]:23: warning: use nullptr
-  // CHECK-FIXES: (double)func1(0, nullptr, nullptr);
-  (double)func1(func0(0, 0), 0, 0);
-  // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: use nullptr
-  // CHECK-MESSAGES: :[[@LINE-2]]:26: warning: use nullptr
-  // CHECK-MESSAGES: :[[@LINE-3]]:30: warning: use nullptr
-  // CHECK-MESSAGES: :[[@LINE-4]]:33: warning: use nullptr
-  // CHECK-FIXES: (double)func1(func0(nullptr, nullptr), nullptr, nullptr);
-}
-
-// FIXME: currently, the check doesn't work as it should with templates.
-template<typename T>
-class A {
- public:
-  A(T *p = NULL) {}
-
-  void f() {
-    Ptr = NULL;
-  }
-  T *Ptr;
-};
-
-template<typename T>
-T *f2(T *a = NULL) {
-  return a ? a : NULL;
-}