[clang-tools-extra] e65b4e7 - [clang-tidy] Avoid invalid fixes in `readability-delete-null-pointer` (#202488)

[via cfe-commits]

Author: flovent
Date: 2026-06-10T16:15:05+08:00
New Revision: e65b4e7fa233fd15fb1e84a66329b8936a594b2d

URL: https://github.com/llvm/llvm-project/commit/e65b4e7fa233fd15fb1e84a66329b8936a594b2d
DIFF: https://github.com/llvm/llvm-project/commit/e65b4e7fa233fd15fb1e84a66329b8936a594b2d.diff

LOG: [clang-tidy] Avoid invalid fixes in `readability-delete-null-pointer` (#202488)

Only provide warnings (not fixits) when `IfStmt` has condition variable
or initializer.

Note that i didn't provide fixit for the situation that conditon
variable is different with the pointer variable being cast to bool
because i think this is rare. (the third newly added testcase)

Closes #202312.

---------

Co-authored-by: Zeyi Xu <zeyi2 at nekoarch.cc>

Added: 
    

Modified: 
    clang-tools-extra/clang-tidy/readability/DeleteNullPointerCheck.cpp
    clang-tools-extra/docs/ReleaseNotes.rst
    clang-tools-extra/test/clang-tidy/checkers/readability/delete-null-pointer.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clang-tidy/readability/DeleteNullPointerCheck.cpp b/clang-tools-extra/clang-tidy/readability/DeleteNullPointerCheck.cpp
index b7e0d9c236973..f469115594611 100644
--- a/clang-tools-extra/clang-tidy/readability/DeleteNullPointerCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/DeleteNullPointerCheck.cpp
@@ -34,8 +34,14 @@ void DeleteNullPointerCheck::registerMatchers(MatchFinder *Finder) {
   const auto BinaryPointerCheckCondition = binaryOperator(hasOperands(
       anyOf(cxxNullPtrLiteralExpr(), integerLiteral(equals(0))), PointerExpr));
 
+  const auto IfWithScopedCondition =
+      ifStmt(anyOf(hasInitStatement(stmt()),
+                   hasConditionVariableStatement(declStmt())))
+          .bind("ifWithScopedCondition");
+
   Finder->addMatcher(
       ifStmt(hasCondition(anyOf(PointerExpr, BinaryPointerCheckCondition)),
+             optionally(IfWithScopedCondition),
              hasThen(anyOf(
                  DeleteExpr, DeleteMemberExpr,
                  compoundStmt(anyOf(has(DeleteExpr), has(DeleteMemberExpr)),
@@ -47,12 +53,14 @@ void DeleteNullPointerCheck::registerMatchers(MatchFinder *Finder) {
 
 void DeleteNullPointerCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *IfWithDelete = Result.Nodes.getNodeAs<IfStmt>("ifWithDelete");
+  const bool HasScopedCondition =
+      Result.Nodes.getNodeAs<IfStmt>("ifWithScopedCondition") != nullptr;
   const auto *Compound = Result.Nodes.getNodeAs<CompoundStmt>("compound");
 
   auto Diag = diag(
       IfWithDelete->getBeginLoc(),
       "'if' statement is unnecessary; deleting null pointer has no effect");
-  if (IfWithDelete->hasElseStorage())
+  if (HasScopedCondition || IfWithDelete->hasElseStorage())
     return;
   // FIXME: generate fixit for this case.
 

diff  --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 8e83ef7feb670..322cf9a781384 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -723,6 +723,10 @@ Changes in existing checks
   - Correctly detecting ``this`` usage when a generic lambda calls an overloaded
     member function.
 
+- Improved :doc:`readability-delete-null-pointer
+  <clang-tidy/checks/readability/delete-null-pointer>` check by avoiding invalid
+  fix-its for ``if`` statements with condition variables or initializers.
+
 - Improved :doc:`readability-else-after-return
   <clang-tidy/checks/readability/else-after-return>` check:
 

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/readability/delete-null-pointer.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/delete-null-pointer.cpp
index b8221c1e296de..a321b1ca8c6cf 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/delete-null-pointer.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/delete-null-pointer.cpp
@@ -156,3 +156,23 @@ void g() {
     delete p6;
   }
 }
+
+struct X {};
+X *makeX();
+struct Y {};
+Y *makeY();
+
+void conditionVariable() {
+  if (X *x = makeX())
+    delete x;
+  // CHECK-MESSAGES: :[[@LINE-2]]:3: warning: 'if' statement is unnecessary; deleting null pointer has no effect
+
+  if (X *x = makeX(); x)
+    delete x;
+  // CHECK-MESSAGES: :[[@LINE-2]]:3: warning: 'if' statement is unnecessary; deleting null pointer has no effect
+
+  X *x = makeX();
+  if (Y *y = makeY(); x)
+    delete x;
+  // CHECK-MESSAGES: :[[@LINE-2]]:3: warning: 'if' statement is unnecessary; deleting null pointer has no effect
+}