[clang] [clang][analyzer] Fix crash caused by overload operator member function with explicit this (PR #132581)

[via cfe-commits]

https://github.com/flovent created https://github.com/llvm/llvm-project/pull/132581

This PR fixs #116372.

>From this PR #83585, CSA starts to model overload operator member function with explicit this as `SimpleFunctionCall` rather than `CXXMemberOperatorCall` (derived from `CXXInstanceCall`), so `CXXInstanceCall` only represents a non-static C++ member function call `with implicit this`.

For this checker, it models `operator=` for STL containers, which always uses implicit this, so the situation using explicit this can be skipped directly.

>From 67ebfb00f7104e63b4a1464f6b015ba8bdea4cc6 Mon Sep 17 00:00:00 2001
From: flovent <flbven at protonmail.com>
Date: Sun, 23 Mar 2025 11:02:53 +0800
Subject: [PATCH] [clang][analyzer] Fix crash caused by overload operator
 member function with explicit this

---
 .../Checkers/ContainerModeling.cpp            |  7 +++++--
 clang/test/Analysis/issue-116372.cpp          | 21 +++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 clang/test/Analysis/issue-116372.cpp

diff --git a/clang/lib/StaticAnalyzer/Checkers/ContainerModeling.cpp b/clang/lib/StaticAnalyzer/Checkers/ContainerModeling.cpp
index 55ed809bfed6c..d850344db6591 100644
--- a/clang/lib/StaticAnalyzer/Checkers/ContainerModeling.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/ContainerModeling.cpp
@@ -157,8 +157,11 @@ void ContainerModeling::checkPostCall(const CallEvent &Call,
   if (Func->isOverloadedOperator()) {
     const auto Op = Func->getOverloadedOperator();
     if (Op == OO_Equal) {
-      // Overloaded 'operator=' must be a non-static member function.
-      const auto *InstCall = cast<CXXInstanceCall>(&Call);
+      // Only handle the assignment operator with implicit this
+      const auto *InstCall = dyn_cast<CXXInstanceCall>(&Call);
+      if (!InstCall)
+        return;
+
       if (cast<CXXMethodDecl>(Func)->isMoveAssignmentOperator()) {
         handleAssignment(C, InstCall->getCXXThisVal(), Call.getOriginExpr(),
                      Call.getArgSVal(0));
diff --git a/clang/test/Analysis/issue-116372.cpp b/clang/test/Analysis/issue-116372.cpp
new file mode 100644
index 0000000000000..0843cd614d87c
--- /dev/null
+++ b/clang/test/Analysis/issue-116372.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_analyze_cc1 -std=c++23 %s -verify -analyzer-checker=alpha.cplusplus.InvalidatedIterator -analyzer-config aggressive-binary-operation-simplification=true
+
+// expected-no-diagnostics
+
+class ExplicitThis {
+  int f = 0;
+public:
+  ExplicitThis();
+  ExplicitThis(ExplicitThis& other);
+
+  ExplicitThis& operator=(this ExplicitThis& self, ExplicitThis const& other) { // no crash
+    self.f = other.f;
+    return self;
+  }
+
+  ~ExplicitThis();
+};
+
+void func(ExplicitThis& obj1) {
+    obj1 = obj1;
+}