[clang-tools-extra] [clang-tidy] Fix when std::ranges::fix is offered on a pointer type in `modernize-use-ranges` (PR #226739)

[Umut Zengin via cfe-commits]

https://github.com/ZenginU created https://github.com/llvm/llvm-project/pull/226739

First PR to LLVM, so will be tagging the reviewers.
@zeyi2 @vbvictor @localspook 

Fixes the pointer derenferencing with the help of `fixit::formatDereference`. Most of the Diff is caused by `RangeArg`refactoring. 

Did not use StringRef as `formatDereference` returns a `std::string`.

Assisted by Codex for codebase exploration and utility usage.

Fixes:
#188257 

Godbolt link from original issuer:
https://godbolt.org/z/7af31ox3j

>From 585393c47572efe2e5ebf047a4e7fd54ec8b76df Mon Sep 17 00:00:00 2001
From: ZenginU <umutzengin00 at gmail.com>
Date: Sat, 26 Sep 2026 18:33:36 -0400
Subject: [PATCH] Fix: Fix when std::ranges::fix is offered on a pointer type.

---
 .../clang-tidy/utils/UseRangesCheck.cpp           | 15 +++++++++++----
 .../clang-tidy/checkers/modernize/use-ranges.cpp  | 15 ++++++++++++++-
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
index e66e1e541e461..6529c23ee5cb6 100644
--- a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "UseRangesCheck.h"
+#include "FixItHintUtils.h"
 #include "Matchers.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Decl.h"
@@ -268,13 +269,19 @@ void UseRangesCheck::check(const MatchFinder::MatchResult &Result) {
     for (const auto &[First, Second, Replace] : Sig) {
       auto ArgNode = ArgName + std::to_string(First);
       if (const auto *ArgExpr = Result.Nodes.getNodeAs<Expr>(ArgNode)) {
-        Diag << FixItHint::CreateReplacement(
-            Call->getArg(Replace == Indexes::Second ? Second : First)
-                ->getSourceRange(),
+        const Expr *RangeArg =
+            Call->getArg(Replace == Indexes::Second ? Second : First);
+        std::string ReplaceText =
             Lexer::getSourceText(
                 CharSourceRange::getTokenRange(ArgExpr->getSourceRange()),
                 Result.Context->getSourceManager(),
-                Result.Context->getLangOpts()));
+                Result.Context->getLangOpts())
+                .str();
+        if (ArgExpr->getType()->isPointerType() &&
+            isa<CXXMemberCallExpr>(RangeArg->IgnoreParenImpCasts()))
+          ReplaceText = fixit::formatDereference(*ArgExpr, *Result.Context);
+        Diag << FixItHint::CreateReplacement(RangeArg->getSourceRange(),
+                                             ReplaceText);
       } else {
         assert(ReverseDescriptor && "Couldn't find forward argument");
         ArgNode.push_back('R');
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 1724b9311e57e..e98234191c15e 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
@@ -11,7 +11,8 @@
 void Positives() {
   std::vector<int> I, J;
   std::vector<std::unique_ptr<int>> K;
-
+  std::vector<int> PointerContainers[2];
+  std::vector<int> *P = PointerContainers;
   // Expect to have no check messages
   std::find(K.begin(), K.end(), nullptr);
 
@@ -27,6 +28,18 @@ void Positives() {
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
   // CHECK-FIXES: std::ranges::find(I, 1);
 
+  std::find(P->cbegin(), P->cend(), 2);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
+  // CHECK-FIXES: std::ranges::find(*P, 2);
+
+  std::find(P->begin(), P->end(), 3);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
+  // CHECK-FIXES: std::ranges::find(*P, 3);
+
+  std::find((P + 1)->begin(), (P + 1)->end(), 4);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
+  // CHECK-FIXES: std::ranges::find(*(P + 1), 4);
+
   std::find(std::begin(I), std::end(I), 2);
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
   // CHECK-FIXES: std::ranges::find(I, 2);