[clang-tools-extra] [clang-tidy] Fix assignment-in-if-condition false positive in statement expressions (PR #231704)

[Daniil Dudkin via cfe-commits]

================
@@ -45,6 +45,23 @@ void AssignmentInIfConditionCheck::check(
           return true;
         }
 
+        // Only traverse the result expression of a statement expression,
+        // looking through labels and attributes on the last statement.
+        bool TraverseStmtExpr(StmtExpr *SE,
+                              DataRecursionQueue *Queue = nullptr) {
+          Stmt *Last = SE->getSubStmt()->body_back();
+          while (Last && !isa<Expr>(Last))
+            if (auto *LS = dyn_cast<LabelStmt>(Last))
+              Last = LS->getSubStmt();
+            else if (auto *AS = dyn_cast<AttributedStmt>(Last))
+              Last = AS->getSubStmt();
+            else
+              return true;
----------------
unterumarmung wrote:

Could we simplify this loop by using `ValueStmt::getExprStmt()`? It seems to already handle unwrapping `LabelStmt` and `AttributedStmt`.

https://github.com/llvm/llvm-project/pull/231704