[clang-tools-extra] [clang-tidy] Fix invalid fixit from modernize-use-ranges for nullptr used with std::unique_ptr (PR #127162)

[via cfe-commits]

https://github.com/Andrewyuan34 updated https://github.com/llvm/llvm-project/pull/127162

>From 7b73f5dfc81d972028382e622888ec71e02b4da2 Mon Sep 17 00:00:00 2001
From: Andrewyuan34 <yiboy at uvic.ca>
Date: Thu, 13 Feb 2025 22:35:36 -0500
Subject: [PATCH 1/2] [clang-tidy] Fix invalid fixit from modernize-use-ranges
 for nullptr used with std::unique_ptr

---
 .../clang-tidy/utils/UseRangesCheck.cpp       | 10 ++++++++
 .../checkers/modernize/use-ranges.cpp         | 25 ++++++++++++++++---
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
index aba4d17ccd035..4c5db488dce7f 100644
--- a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
@@ -215,6 +215,16 @@ void UseRangesCheck::check(const MatchFinder::MatchResult &Result) {
     const auto *Call = Result.Nodes.getNodeAs<CallExpr>(Buffer);
     if (!Call)
       continue;
+    if (Function->getName() == "find") {
+      unsigned ValueArgIndex = 2;
+      if (Call->getNumArgs() <= ValueArgIndex)
+        continue;
+      const Expr *ValueExpr =
+          Call->getArg(ValueArgIndex)->IgnoreParenImpCasts();
+      if (isa<CXXNullPtrLiteralExpr>(ValueExpr)) {
+        return;
+      }
+    }
     auto Diag = createDiag(*Call);
     if (auto ReplaceName = Replacer->getReplaceName(*Function))
       Diag << FixItHint::CreateReplacement(Call->getCallee()->getSourceRange(),
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-ranges.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-ranges.cpp
index b022efebfdf4d..57ca038f64511 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-ranges.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-ranges.cpp
@@ -1,14 +1,24 @@
-// RUN: %check_clang_tidy -std=c++20 %s modernize-use-ranges %t -- -- -I %S/Inputs/use-ranges/
-// RUN: %check_clang_tidy -std=c++23 %s modernize-use-ranges %t -check-suffixes=,CPP23 -- -I %S/Inputs/use-ranges/
+// RUN: %check_clang_tidy -std=c++20 %s modernize-use-ranges %t -- -- -I %S/Inputs/
+// RUN: %check_clang_tidy -std=c++23 %s modernize-use-ranges %t -check-suffixes=,CPP23 -- -I %S/Inputs/
+// Example: ./check_clang_tidy.py -std=c++20 checkers/modernize/use-ranges.cpp modernize-use-ranges temp.txt -- -- -I ~/llvm-project/clang-tools-extra/test/clang-tidy/checkers/modernize/Inputs/
 
 // CHECK-FIXES: #include <algorithm>
 // CHECK-FIXES-CPP23: #include <numeric>
 // CHECK-FIXES: #include <ranges>
 
-#include "fake_std.h"
+#include "use-ranges/fake_std.h"
+#include "smart-ptr/unique_ptr.h"
 
 void Positives() {
   std::vector<int> I, J;
+
+  // Expect to have no check messages
+  std::find(I.begin(), I.end(), nullptr);
+
+  std::find(I.begin(), I.end(), std::unique_ptr<int>());
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
+  // CHECK-FIXES: std::ranges::find(I, std::unique_ptr<int>());
+
   std::find(I.begin(), I.end(), 0);
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
   // CHECK-FIXES: std::ranges::find(I, 0);
@@ -76,6 +86,14 @@ void Positives() {
 
 void Reverse(){
   std::vector<int> I, J;
+  
+  // Expect to have no check messages
+  std::find(I.rbegin(), I.rend(), nullptr);
+
+  std::find(I.rbegin(), I.rend(), std::unique_ptr<int>());
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
+  // CHECK-FIXES: std::ranges::find(std::ranges::reverse_view(I), std::unique_ptr<int>());
+
   std::find(I.rbegin(), I.rend(), 0);
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
   // CHECK-FIXES: std::ranges::find(std::ranges::reverse_view(I), 0);
@@ -112,3 +130,4 @@ void Negatives() {
   // Pathological, but probably shouldn't diagnose this
   std::rotate(I.begin(), I.end(), I.end() + 0);
 }
+

>From ae08073e5b318fbdad17a2441a96f42ff622d8ea Mon Sep 17 00:00:00 2001
From: Andrewyuan34 <yiboy at uvic.ca>
Date: Fri, 14 Feb 2025 01:15:46 -0500
Subject: [PATCH 2/2] Based on PR reviews, improve code quality by making sure
 const correctness and modifying code format

Co-authored-by: Piotr Zegar <me at piotrzegar.pl>
---
 clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
index 4c5db488dce7f..bb5f12aa28c49 100644
--- a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
@@ -216,7 +216,7 @@ void UseRangesCheck::check(const MatchFinder::MatchResult &Result) {
     if (!Call)
       continue;
     if (Function->getName() == "find") {
-      unsigned ValueArgIndex = 2;
+      const unsigned ValueArgIndex = 2;
       if (Call->getNumArgs() <= ValueArgIndex)
         continue;
       const Expr *ValueExpr =