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Merged
merged 5 commits into from
Sep 4, 2025
Merged

[clang-tidy] Raise minimum standard level for several checks from C++98 to C++11 #152401

merged 5 commits into from
Sep 4, 2025
+35 −105

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localspook
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@localspook localspook commented Aug 6, 2025 •
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modernize-replace-auto-ptr, modernize-use-equals-delete, and modernize-use-auto use std::unique_ptr, = delete, and auto respectively, which are all C++11 features.

The interesting bit is modernize-use-nullptr's tests:

  • Some relied on int-to-pointer conversions that were removed in C++11. There are two variations here. First, tests like this, which become ill-formed: 
    const int null = 0;
void * ptr = null;
    I just deleted these cases; if they're ill-formed, we're not losing anything, right?
    Second, tests like this: 
    float * ptr = (float *)int(0.f);
    These don't become ill-formed, but start generating a different AST. In C++98, they are NullToPointer conversions, but in C++11, they become generic IntegralToPointer conversions. I deleted these cases too, though I'm less sure here.
  • Folded struct Bar into class A, because those both suffer from the same false negatives.

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llvmbot commented Aug 6, 2025

@llvm/pr-subscribers-clang-tools-extra

Author: Victor Chernyakin (localspook)

Changes

modernize-replace-auto-ptr, modernize-use-equals-delete, and modernize-use-auto use std::unique_ptr, = delete, and auto respectively, which are all C++11 features.

The interesting bit is modernize-use-nullptr's tests:

  • Some relied on int-to-pointer conversions that were removed in C++11. I just deleted these cases; if they're ill-formed, we're not losing anything, right?
  • Uncovered some cases that are false negatives in C++11 mode.

Full diff: https://github.com/llvm/llvm-project/pull/152401.diff

5 Files Affected:

  • (modified) clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h (+1-1)
  • (modified) clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h (+1-1)
  • (modified) clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h (+1-1)
  • (modified) clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h (+1-3)
  • (modified) clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-basic.cpp (+25-77)
diff --git a/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h b/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h
index 636481300d730..c91f5f580c524 100644
--- a/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h
@@ -42,7 +42,7 @@ class ReplaceAutoPtrCheck : public ClangTidyCheck {
 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
index 76c52b2d28139..7a9bbbe1cdf77 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h
@@ -17,7 +17,7 @@ class UseAutoCheck : public ClangTidyCheck {
 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/UseEqualsDeleteCheck.h b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
index 64f60351c0657..dc3e712482c21 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
@@ -23,7 +23,7 @@ class UseEqualsDeleteCheck : public ClangTidyCheck {
 public:
   UseEqualsDeleteCheck(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/UseNullptrCheck.h b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
index f1591bae44657..4c02f8ccdf303 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
@@ -17,9 +17,7 @@ class UseNullptrCheck : public ClangTidyCheck {
 public:
   UseNullptrCheck(StringRef Name, ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    // FIXME this should be CPlusPlus11 but that causes test cases to
-    // erroneously fail.
-    return LangOpts.CPlusPlus || LangOpts.C23;
+    return LangOpts.CPlusPlus11 || LangOpts.C23;
   }
   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
index 2579099148e3a..4f69ec5aeeb4c 100644
--- 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
@@ -1,9 +1,4 @@
-// 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.
+// RUN: %check_clang_tidy %s modernize-use-nullptr %t -- -- -Wno-non-literal-null-conversion
 
 const unsigned int g_null = 0;
 #define NULL 0
@@ -23,11 +18,7 @@ void test_assignment() {
   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;
-
+  int *p3;
   p3 = NULL;
   // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: use nullptr
   // CHECK-FIXES: p3 = nullptr;
@@ -35,14 +26,11 @@ void test_assignment() {
   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;
 
+  const int null = 0;
   int i3 = null;
 
   int *p5, *p6, *p7;
@@ -70,33 +58,30 @@ int *Foo::m_p2 = NULL;
 // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: use nullptr
 // CHECK-FIXES: int *Foo::m_p2 = nullptr;
 
+// FIXME: all these DISABLED-* cases should trigger the warning.
 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);
+    // DISABLED-CHECK-MESSAGES: :[[@LINE-1]]:27: warning: use nullptr
+    // DISABLED-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;
+    // DISABLED-CHECK-MESSAGES: :[[@LINE-1]]:11: warning: use nullptr
+    // DISABLED-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;
+    // DISABLED-CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr
+    // DISABLED-CHECK-FIXES: T *i2 = nullptr;
   }
 
   T *m_p;
@@ -108,9 +93,7 @@ struct Baz {
 };
 
 void test_cxx_cases() {
-  Foo f(g_null);
-  // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use nullptr
-  // CHECK-FIXES: Foo f(nullptr);
+  Foo f;
 
   f.bar(NULL);
   // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use nullptr
@@ -122,10 +105,6 @@ void test_cxx_cases() {
   // 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
@@ -144,10 +123,6 @@ 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) {}
@@ -161,10 +136,6 @@ void test_function_call() {
   // 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);
 }
 
@@ -180,51 +151,33 @@ void *test_function_return2() {
   // 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() {
+int test_function_return3() {
   return 0;
 }
 
-int test_function_return5() {
+int test_function_return4() {
   return NULL;
 }
 
-int test_function_return6() {
+int test_function_return5() {
   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() {
+int *test_function_return_cast() {
 #define RET return
-  RET(int)0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: use nullptr
+  RET 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: use nullptr
   // CHECK-FIXES: RET nullptr;
 #undef RET
 }
 
 // Test parentheses expressions resulting in a nullptr.
-int *test_parentheses_expression1() {
+int *test_parentheses_expression() {
   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
@@ -243,10 +196,11 @@ void *test_parentheses_explicit_cast_sequence1() {
   // CHECK-FIXES: return(static_cast<void*>(nullptr));
 }
 
+// FIXME: this case should trigger the warning.
 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));
+  // DISABLED-CHECK-MESSAGES: :[[@LINE-1]]:29: warning: use nullptr
+  // DISABLED-CHECK-FIXES: return(static_cast<void*>(nullptr));
 }
 
 // Test explicit cast expressions resulting in nullptr.
@@ -313,19 +267,13 @@ void test_const_pointers() {
   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;
+  const int *const_p3 = (int*)0;
   // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: use nullptr
-  // CHECK-FIXES: const int *const_p5 = (int*)nullptr;
+  // CHECK-FIXES: const int *const_p3 = (int*)nullptr;
   int *t;
-  const int *const_p6 = static_cast<int*>(t ? t : static_cast<int*>(0));
+  const int *const_p4 = 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));
+  // CHECK-FIXES: const int *const_p4 = static_cast<int*>(t ? t : static_cast<int*>(nullptr));
 }
 
 void test_nested_implicit_cast_expr() {

@llvmbot
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llvmbot commented Aug 6, 2025

@llvm/pr-subscribers-clang-tidy

Author: Victor Chernyakin (localspook)

Changes

modernize-replace-auto-ptr, modernize-use-equals-delete, and modernize-use-auto use std::unique_ptr, = delete, and auto respectively, which are all C++11 features.

The interesting bit is modernize-use-nullptr's tests:

  • Some relied on int-to-pointer conversions that were removed in C++11. I just deleted these cases; if they're ill-formed, we're not losing anything, right?
  • Uncovered some cases that are false negatives in C++11 mode.

Full diff: https://github.com/llvm/llvm-project/pull/152401.diff

5 Files Affected:

  • (modified) clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h (+1-1)
  • (modified) clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h (+1-1)
  • (modified) clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h (+1-1)
  • (modified) clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h (+1-3)
  • (modified) clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-basic.cpp (+25-77)
diff --git a/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h b/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h
index 636481300d730..c91f5f580c524 100644
--- a/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h
@@ -42,7 +42,7 @@ class ReplaceAutoPtrCheck : public ClangTidyCheck {
 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
index 76c52b2d28139..7a9bbbe1cdf77 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.h
@@ -17,7 +17,7 @@ class UseAutoCheck : public ClangTidyCheck {
 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/UseEqualsDeleteCheck.h b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
index 64f60351c0657..dc3e712482c21 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
@@ -23,7 +23,7 @@ class UseEqualsDeleteCheck : public ClangTidyCheck {
 public:
   UseEqualsDeleteCheck(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/UseNullptrCheck.h b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
index f1591bae44657..4c02f8ccdf303 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
@@ -17,9 +17,7 @@ class UseNullptrCheck : public ClangTidyCheck {
 public:
   UseNullptrCheck(StringRef Name, ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    // FIXME this should be CPlusPlus11 but that causes test cases to
-    // erroneously fail.
-    return LangOpts.CPlusPlus || LangOpts.C23;
+    return LangOpts.CPlusPlus11 || LangOpts.C23;
   }
   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
index 2579099148e3a..4f69ec5aeeb4c 100644
--- 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
@@ -1,9 +1,4 @@
-// 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.
+// RUN: %check_clang_tidy %s modernize-use-nullptr %t -- -- -Wno-non-literal-null-conversion
 
 const unsigned int g_null = 0;
 #define NULL 0
@@ -23,11 +18,7 @@ void test_assignment() {
   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;
-
+  int *p3;
   p3 = NULL;
   // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: use nullptr
   // CHECK-FIXES: p3 = nullptr;
@@ -35,14 +26,11 @@ void test_assignment() {
   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;
 
+  const int null = 0;
   int i3 = null;
 
   int *p5, *p6, *p7;
@@ -70,33 +58,30 @@ int *Foo::m_p2 = NULL;
 // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: use nullptr
 // CHECK-FIXES: int *Foo::m_p2 = nullptr;
 
+// FIXME: all these DISABLED-* cases should trigger the warning.
 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);
+    // DISABLED-CHECK-MESSAGES: :[[@LINE-1]]:27: warning: use nullptr
+    // DISABLED-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;
+    // DISABLED-CHECK-MESSAGES: :[[@LINE-1]]:11: warning: use nullptr
+    // DISABLED-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;
+    // DISABLED-CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr
+    // DISABLED-CHECK-FIXES: T *i2 = nullptr;
   }
 
   T *m_p;
@@ -108,9 +93,7 @@ struct Baz {
 };
 
 void test_cxx_cases() {
-  Foo f(g_null);
-  // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use nullptr
-  // CHECK-FIXES: Foo f(nullptr);
+  Foo f;
 
   f.bar(NULL);
   // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use nullptr
@@ -122,10 +105,6 @@ void test_cxx_cases() {
   // 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
@@ -144,10 +123,6 @@ 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) {}
@@ -161,10 +136,6 @@ void test_function_call() {
   // 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);
 }
 
@@ -180,51 +151,33 @@ void *test_function_return2() {
   // 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() {
+int test_function_return3() {
   return 0;
 }
 
-int test_function_return5() {
+int test_function_return4() {
   return NULL;
 }
 
-int test_function_return6() {
+int test_function_return5() {
   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() {
+int *test_function_return_cast() {
 #define RET return
-  RET(int)0;
-  // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: use nullptr
+  RET 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: use nullptr
   // CHECK-FIXES: RET nullptr;
 #undef RET
 }
 
 // Test parentheses expressions resulting in a nullptr.
-int *test_parentheses_expression1() {
+int *test_parentheses_expression() {
   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
@@ -243,10 +196,11 @@ void *test_parentheses_explicit_cast_sequence1() {
   // CHECK-FIXES: return(static_cast<void*>(nullptr));
 }
 
+// FIXME: this case should trigger the warning.
 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));
+  // DISABLED-CHECK-MESSAGES: :[[@LINE-1]]:29: warning: use nullptr
+  // DISABLED-CHECK-FIXES: return(static_cast<void*>(nullptr));
 }
 
 // Test explicit cast expressions resulting in nullptr.
@@ -313,19 +267,13 @@ void test_const_pointers() {
   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;
+  const int *const_p3 = (int*)0;
   // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: use nullptr
-  // CHECK-FIXES: const int *const_p5 = (int*)nullptr;
+  // CHECK-FIXES: const int *const_p3 = (int*)nullptr;
   int *t;
-  const int *const_p6 = static_cast<int*>(t ? t : static_cast<int*>(0));
+  const int *const_p4 = 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));
+  // CHECK-FIXES: const int *const_p4 = static_cast<int*>(t ? t : static_cast<int*>(nullptr));
 }
 
 void test_nested_implicit_cast_expr() {

@vbvictor
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vbvictor commented Aug 8, 2025

For some reason, there's also variation between OSes.

Some warnings on Windows doesn't show probably because there is no -fno-delayed-template-parsing. You could add this flag and check if some tests begin to pass.

Also, I think we could use -target flag to specify the OS and not disable tests for all OSes.

@localspook
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-fno-delayed-template-parsing did the trick for some tests! And it was a good hint that helped me figure out why the others were inconsistent: -fms-extensions apparently enables C++98-style int-to-pointer conversions in higher language versions, which affects the generated AST. I've updated the PR description to cover the changes.

carlosgalvezp
carlosgalvezp approved these changes Sep 3, 2025
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LGTM, couple tiny comments/questions

@localspook localspook merged commit bcb3bd0 into llvm:main Sep 4, 2025
9 checks passed
@localspook localspook deleted the only-in-cpp11 branch September 4, 2025 17:33
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@carlosgalvezp carlosgalvezp carlosgalvezp approved these changes

@5chmidti 5chmidti 5chmidti approved these changes

@PiotrZSL PiotrZSL Awaiting requested review from PiotrZSL

@vbvictor vbvictor Awaiting requested review from vbvictor

@HerrCai0907 HerrCai0907 Awaiting requested review from HerrCai0907

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