[clang-tools-extra] [clang-tidy]suggest use `std::span` as replacement of c array in C++20 for modernize-avoid-c-arrays (PR #108555)

Congcong Cai via cfe-commits cfe-commits at lists.llvm.org
Tue Sep 17 08:12:59 PDT 2024


https://github.com/HerrCai0907 updated https://github.com/llvm/llvm-project/pull/108555

>From 35742b5f2f085b8f6626456cd0d21ebecbe8f831 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcong.cai at bmw.com>
Date: Thu, 12 Sep 2024 23:11:51 +0800
Subject: [PATCH 1/4] [clang-tidy]suggest use `std::span` as replacement of c
 array in C++20 for modernize-avoid-c-arrays

---
 .../modernize/AvoidCArraysCheck.cpp           | 26 ++++++++++++++++---
 clang-tools-extra/docs/ReleaseNotes.rst       |  4 +++
 .../modernize/avoid-c-arrays-c++20.cpp        |  7 +++++
 .../modernize/avoid-c-arrays-ignores-main.cpp |  6 ++---
 .../avoid-c-arrays-ignores-strings.cpp        |  4 +--
 .../avoid-c-arrays-ignores-three-arg-main.cpp | 10 +++----
 .../checkers/modernize/avoid-c-arrays.cpp     |  4 +--
 7 files changed, 46 insertions(+), 15 deletions(-)
 create mode 100644 clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp

diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
index 89790ea70cf229..9fd0259ed1aacf 100644
--- a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
@@ -9,6 +9,7 @@
 #include "AvoidCArraysCheck.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
 
 using namespace clang::ast_matchers;
 
@@ -38,6 +39,13 @@ AST_MATCHER(clang::ParmVarDecl, isArgvOfMain) {
   return FD ? FD->isMain() : false;
 }
 
+AST_MATCHER_P(clang::TypeLoc, alwaysTrue,
+              clang::ast_matchers::internal::Matcher<clang::TypeLoc>,
+              InnerMatcher) {
+  InnerMatcher.matches(Node, Finder, Builder);
+  return true;
+}
+
 } // namespace
 
 AvoidCArraysCheck::AvoidCArraysCheck(StringRef Name, ClangTidyContext *Context)
@@ -60,6 +68,7 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
 
   Finder->addMatcher(
       typeLoc(hasValidBeginLoc(), hasType(arrayType()),
+              alwaysTrue(hasParent(parmVarDecl().bind("param_decl"))),
               unless(anyOf(hasParent(parmVarDecl(isArgvOfMain())),
                            hasParent(varDecl(isExternC())),
                            hasParent(fieldDecl(
@@ -72,11 +81,22 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
 
 void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *ArrayType = Result.Nodes.getNodeAs<TypeLoc>("typeloc");
-
+  bool const IsInParam =
+      Result.Nodes.getNodeAs<ParmVarDecl>("param_decl") != nullptr;
+  const bool IsVLA = ArrayType->getTypePtr()->isVariableArrayType();
+  // in function parameter, we also don't know the size of IncompleteArrayType.
+  const bool IsUnknownSize =
+      IsVLA || (ArrayType->getTypePtr()->isIncompleteArrayType() && IsInParam);
+  enum class RecommendType { Array, Vector, Span };
+  const RecommendType RecommendType =
+      (IsInParam && Result.Context->getLangOpts().CPlusPlus20)
+          ? RecommendType::Span
+      : IsUnknownSize ? RecommendType::Vector
+                      : RecommendType::Array;
   diag(ArrayType->getBeginLoc(),
        "do not declare %select{C-style|C VLA}0 arrays, use "
-       "%select{std::array<>|std::vector<>}0 instead")
-      << ArrayType->getTypePtr()->isVariableArrayType();
+       "%select{std::array<>|std::vector<>|std::span<>}1 instead")
+      << IsVLA << static_cast<int>(RecommendType);
 }
 
 } // namespace clang::tidy::modernize
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 1ad8cedc902cb5..c5a2b3c36d130f 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -111,6 +111,10 @@ Changes in existing checks
   <clang-tidy/checks/bugprone/casting-through-void>` check to suggest replacing
   the offending code with ``reinterpret_cast``, to more clearly express intent.
 
+- Improved :doc:`modernize-avoid-c-arrays
+  <clang-tidy/checks/modernize/avoid-c-arrays>` check to suggest use std::span
+  as replacement of c array in C++20.
+
 - Improved :doc:`modernize-use-std-format
   <clang-tidy/checks/modernize/use-std-format>` check to support replacing
   member function calls too.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp
new file mode 100644
index 00000000000000..a9298245feaaeb
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp
@@ -0,0 +1,7 @@
+// RUN: %check_clang_tidy -std=c++20 %s modernize-avoid-c-arrays %t
+
+int foo(int data[], int size) {
+  // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: do not declare C-style arrays, use std::span<> instead
+  int f4[] = {1, 2};
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
+}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp
index 6549422f393aaa..f833a85164f333 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp
@@ -1,7 +1,7 @@
-// RUN: %check_clang_tidy %s modernize-avoid-c-arrays %t
+// RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t
 
 int not_main(int argc, char *argv[]) {
-  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::array<> instead
+  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::vector<> instead
   int f4[] = {1, 2};
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
 }
@@ -11,7 +11,7 @@ int main(int argc, char *argv[]) {
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
 
   auto not_main = [](int argc, char *argv[]) {
-    // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::array<> instead
+    // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::vector<> instead
     int f6[] = {1, 2};
     // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: do not declare C-style arrays, use std::array<> instead
   };
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp
index f6d64848f9e3a0..c8277feb3958bf 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s modernize-avoid-c-arrays %t -- \
+// RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t -- \
 // RUN:  -config='{CheckOptions: { modernize-avoid-c-arrays.AllowStringArrays: true }}'
 
 const char name[] = "name";
@@ -6,4 +6,4 @@ const char array[] = {'n', 'a', 'm', 'e', '\0'};
 // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays]
 
 void takeCharArray(const char name[]);
-// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays]
+// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::vector<> instead [modernize-avoid-c-arrays]
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp
index 22a4016f79f4da..ae2e0bc9c10035 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp
@@ -1,8 +1,8 @@
-// RUN: %check_clang_tidy %s modernize-avoid-c-arrays %t
+// RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t
 
 int not_main(int argc, char *argv[], char *argw[]) {
-  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::array<> instead
-  // CHECK-MESSAGES: :[[@LINE-2]]:38: warning: do not declare C-style arrays, use std::array<> instead
+  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::vector<> instead
+  // CHECK-MESSAGES: :[[@LINE-2]]:38: warning: do not declare C-style arrays, use std::vector<> instead
   int f4[] = {1, 2};
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
 }
@@ -12,8 +12,8 @@ int main(int argc, char *argv[], char *argw[]) {
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
 
   auto not_main = [](int argc, char *argv[], char *argw[]) {
-    // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::array<> instead
-    // CHECK-MESSAGES: :[[@LINE-2]]:46: warning: do not declare C-style arrays, use std::array<> instead
+    // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::vector<> instead
+    // CHECK-MESSAGES: :[[@LINE-2]]:46: warning: do not declare C-style arrays, use std::vector<> instead
     int f6[] = {1, 2};
     // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: do not declare C-style arrays, use std::array<> instead
   };
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp
index ce99f0821b2230..15fc4d4954c867 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s modernize-avoid-c-arrays %t
+// RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t
 
 int a[] = {1, 2};
 // CHECK-MESSAGES: :[[@LINE-1]]:1: warning: do not declare C-style arrays, use std::array<> instead
@@ -91,4 +91,4 @@ const char name[] = "Some string";
 // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays]
 
 void takeCharArray(const char name[]);
-// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays]
+// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::vector<> instead [modernize-avoid-c-arrays]

>From 3912ba85d649730567c29bda91c735d3b4301186 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Fri, 13 Sep 2024 22:28:41 +0800
Subject: [PATCH 2/4] recommend std::array for fixed size parameter

---
 .../modernize/AvoidCArraysCheck.cpp           | 20 ++++++++++---------
 .../modernize/avoid-c-arrays-c++20.cpp        |  8 ++++++--
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
index 9fd0259ed1aacf..5db9df41ef2cb9 100644
--- a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
@@ -81,18 +81,20 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
 
 void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *ArrayType = Result.Nodes.getNodeAs<TypeLoc>("typeloc");
-  bool const IsInParam =
+  const bool IsInParam =
       Result.Nodes.getNodeAs<ParmVarDecl>("param_decl") != nullptr;
   const bool IsVLA = ArrayType->getTypePtr()->isVariableArrayType();
-  // in function parameter, we also don't know the size of IncompleteArrayType.
-  const bool IsUnknownSize =
-      IsVLA || (ArrayType->getTypePtr()->isIncompleteArrayType() && IsInParam);
   enum class RecommendType { Array, Vector, Span };
-  const RecommendType RecommendType =
-      (IsInParam && Result.Context->getLangOpts().CPlusPlus20)
-          ? RecommendType::Span
-      : IsUnknownSize ? RecommendType::Vector
-                      : RecommendType::Array;
+  RecommendType RecommendType = RecommendType::Array;
+  if (IsVLA) {
+    RecommendType = RecommendType::Vector;
+  } else if (ArrayType->getTypePtr()->isIncompleteArrayType() && IsInParam) {
+    // in function parameter, we also don't know the size of
+    // IncompleteArrayType.
+    RecommendType = Result.Context->getLangOpts().CPlusPlus20
+                        ? RecommendType::Span
+                        : RecommendType::Vector;
+  }
   diag(ArrayType->getBeginLoc(),
        "do not declare %select{C-style|C VLA}0 arrays, use "
        "%select{std::array<>|std::vector<>|std::span<>}1 instead")
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp
index a9298245feaaeb..e53cfeba0e4601 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp
@@ -1,7 +1,11 @@
 // RUN: %check_clang_tidy -std=c++20 %s modernize-avoid-c-arrays %t
 
-int foo(int data[], int size) {
-  // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: do not declare C-style arrays, use std::span<> instead
+int f1(int data[], int size) {
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: do not declare C-style arrays, use std::span<> instead
   int f4[] = {1, 2};
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
 }
+
+int f2(int data[100]) {
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: do not declare C-style arrays, use std::array<> instead
+}

>From f7399cf0cf0a3fb4dfc8e955fb36dadfca243443 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Sat, 14 Sep 2024 17:27:21 +0800
Subject: [PATCH 3/4] use std::array<> or std::vector<>

---
 .../modernize/AvoidCArraysCheck.cpp           | 30 +++++++++----------
 clang-tools-extra/docs/ReleaseNotes.rst       |  5 ++--
 .../checks/modernize/avoid-c-arrays.rst       |  3 ++
 .../modernize/avoid-c-arrays-ignores-main.cpp |  4 +--
 .../avoid-c-arrays-ignores-strings.cpp        |  2 +-
 .../avoid-c-arrays-ignores-three-arg-main.cpp |  8 ++---
 .../checkers/modernize/avoid-c-arrays.cpp     |  2 +-
 7 files changed, 28 insertions(+), 26 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
index 5db9df41ef2cb9..87df3f21cb40dd 100644
--- a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
@@ -39,13 +39,6 @@ AST_MATCHER(clang::ParmVarDecl, isArgvOfMain) {
   return FD ? FD->isMain() : false;
 }
 
-AST_MATCHER_P(clang::TypeLoc, alwaysTrue,
-              clang::ast_matchers::internal::Matcher<clang::TypeLoc>,
-              InnerMatcher) {
-  InnerMatcher.matches(Node, Finder, Builder);
-  return true;
-}
-
 } // namespace
 
 AvoidCArraysCheck::AvoidCArraysCheck(StringRef Name, ClangTidyContext *Context)
@@ -68,7 +61,7 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
 
   Finder->addMatcher(
       typeLoc(hasValidBeginLoc(), hasType(arrayType()),
-              alwaysTrue(hasParent(parmVarDecl().bind("param_decl"))),
+              optionally(hasParent(parmVarDecl().bind("param_decl"))),
               unless(anyOf(hasParent(parmVarDecl(isArgvOfMain())),
                            hasParent(varDecl(isExternC())),
                            hasParent(fieldDecl(
@@ -85,20 +78,25 @@ void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
       Result.Nodes.getNodeAs<ParmVarDecl>("param_decl") != nullptr;
   const bool IsVLA = ArrayType->getTypePtr()->isVariableArrayType();
   enum class RecommendType { Array, Vector, Span };
-  RecommendType RecommendType = RecommendType::Array;
+  llvm::SmallVector<const char *> RecommendTypes{};
   if (IsVLA) {
-    RecommendType = RecommendType::Vector;
+    RecommendTypes.push_back("std::vector<>");
   } else if (ArrayType->getTypePtr()->isIncompleteArrayType() && IsInParam) {
     // in function parameter, we also don't know the size of
     // IncompleteArrayType.
-    RecommendType = Result.Context->getLangOpts().CPlusPlus20
-                        ? RecommendType::Span
-                        : RecommendType::Vector;
+    if (Result.Context->getLangOpts().CPlusPlus20)
+      RecommendTypes.push_back("std::span<>");
+    else {
+      RecommendTypes.push_back("std::array<>");
+      RecommendTypes.push_back("std::vector<>");
+    }
+  } else {
+    RecommendTypes.push_back("std::array<>");
   }
+  llvm::errs() << llvm::join(RecommendTypes, " or ") << "\n";
   diag(ArrayType->getBeginLoc(),
-       "do not declare %select{C-style|C VLA}0 arrays, use "
-       "%select{std::array<>|std::vector<>|std::span<>}1 instead")
-      << IsVLA << static_cast<int>(RecommendType);
+       "do not declare %select{C-style|C VLA}0 arrays, use %1 instead")
+      << IsVLA << llvm::join(RecommendTypes, " or ");
 }
 
 } // namespace clang::tidy::modernize
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 4c7dd4a0c932f6..1326d539ee217e 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -112,8 +112,9 @@ Changes in existing checks
   the offending code with ``reinterpret_cast``, to more clearly express intent.
 
 - Improved :doc:`modernize-avoid-c-arrays
-  <clang-tidy/checks/modernize/avoid-c-arrays>` check to suggest use std::span
-  as replacement of c array in C++20.
+  <clang-tidy/checks/modernize/avoid-c-arrays>` check to suggest using 
+  ``std::span`` as replacement of incomplete C array in C++20 and ``std::vector`` 
+  in the versions before C++20.
 
 - Improved :doc:`modernize-use-std-format
   <clang-tidy/checks/modernize/use-std-format>` check to support replacing
diff --git a/clang-tools-extra/docs/clang-tidy/checks/modernize/avoid-c-arrays.rst b/clang-tools-extra/docs/clang-tidy/checks/modernize/avoid-c-arrays.rst
index 8f13ca4466a310..2d72352989ab94 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/modernize/avoid-c-arrays.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/modernize/avoid-c-arrays.rst
@@ -10,6 +10,9 @@ modernize-avoid-c-arrays
 Finds C-style array types and recommend to use ``std::array<>`` /
 ``std::vector<>``. All types of C arrays are diagnosed.
 
+For incomplete C-style array types appeared in parameters, It would be better to
+use ``std::span`` / ``gsl::span`` as replacement.
+
 However, fix-it are potentially dangerous in header files and are therefore not
 emitted right now.
 
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp
index f833a85164f333..ad12b3d6f95b91 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp
@@ -1,7 +1,7 @@
 // RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t
 
 int not_main(int argc, char *argv[]) {
-  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::vector<> instead
+  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead
   int f4[] = {1, 2};
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
 }
@@ -11,7 +11,7 @@ int main(int argc, char *argv[]) {
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
 
   auto not_main = [](int argc, char *argv[]) {
-    // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::vector<> instead
+    // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead
     int f6[] = {1, 2};
     // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: do not declare C-style arrays, use std::array<> instead
   };
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp
index c8277feb3958bf..b607068f5b7c9c 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp
@@ -6,4 +6,4 @@ const char array[] = {'n', 'a', 'm', 'e', '\0'};
 // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays]
 
 void takeCharArray(const char name[]);
-// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::vector<> instead [modernize-avoid-c-arrays]
+// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead [modernize-avoid-c-arrays]
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp
index ae2e0bc9c10035..c04edf2b5aea08 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp
@@ -1,8 +1,8 @@
 // RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t
 
 int not_main(int argc, char *argv[], char *argw[]) {
-  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::vector<> instead
-  // CHECK-MESSAGES: :[[@LINE-2]]:38: warning: do not declare C-style arrays, use std::vector<> instead
+  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead
+  // CHECK-MESSAGES: :[[@LINE-2]]:38: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead
   int f4[] = {1, 2};
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
 }
@@ -12,8 +12,8 @@ int main(int argc, char *argv[], char *argw[]) {
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead
 
   auto not_main = [](int argc, char *argv[], char *argw[]) {
-    // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::vector<> instead
-    // CHECK-MESSAGES: :[[@LINE-2]]:46: warning: do not declare C-style arrays, use std::vector<> instead
+    // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead
+    // CHECK-MESSAGES: :[[@LINE-2]]:46: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead
     int f6[] = {1, 2};
     // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: do not declare C-style arrays, use std::array<> instead
   };
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp
index 15fc4d4954c867..b0aaa4962a8351 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp
@@ -91,4 +91,4 @@ const char name[] = "Some string";
 // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays]
 
 void takeCharArray(const char name[]);
-// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::vector<> instead [modernize-avoid-c-arrays]
+// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead [modernize-avoid-c-arrays]

>From aa477f5ebadee5c1952643702c53e47eb8de2056 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Tue, 17 Sep 2024 23:03:44 +0800
Subject: [PATCH 4/4] split comment

---
 .../clang-tidy/modernize/AvoidCArraysCheck.cpp              | 1 -
 clang-tools-extra/docs/ReleaseNotes.rst                     | 6 +++---
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
index 87df3f21cb40dd..98778192dbd3ae 100644
--- a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
@@ -93,7 +93,6 @@ void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
   } else {
     RecommendTypes.push_back("std::array<>");
   }
-  llvm::errs() << llvm::join(RecommendTypes, " or ") << "\n";
   diag(ArrayType->getBeginLoc(),
        "do not declare %select{C-style|C VLA}0 arrays, use %1 instead")
       << IsVLA << llvm::join(RecommendTypes, " or ");
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 1326d539ee217e..830ea3cbb8fd3d 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -112,9 +112,9 @@ Changes in existing checks
   the offending code with ``reinterpret_cast``, to more clearly express intent.
 
 - Improved :doc:`modernize-avoid-c-arrays
-  <clang-tidy/checks/modernize/avoid-c-arrays>` check to suggest using 
-  ``std::span`` as replacement of incomplete C array in C++20 and ``std::vector`` 
-  in the versions before C++20.
+  <clang-tidy/checks/modernize/avoid-c-arrays>` check to suggest using ``std::span``
+  as a replacement for parameters of incomplete C array type in C++20 and 
+  ``std::array`` or ``std::vector`` before C++20.
 
 - Improved :doc:`modernize-use-std-format
   <clang-tidy/checks/modernize/use-std-format>` check to support replacing



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