[clang-tools-extra] [clang-tidy] Add check bugprone-misleading-setter-of-reference (PR #132242)

[Baranov Victor via cfe-commits]

================
@@ -0,0 +1,61 @@
+//===--- MisleadingSetterOfReferenceCheck.cpp - clang-tidy-----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "MisleadingSetterOfReferenceCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+void MisleadingSetterOfReferenceCheck::registerMatchers(MatchFinder *Finder) {
+  auto RefField = fieldDecl(hasType(hasCanonicalType(referenceType(
+                                pointee(equalsBoundNode("type"))))))
+                      .bind("member");
+  auto AssignLHS = memberExpr(
+      hasObjectExpression(ignoringParenCasts(cxxThisExpr())), member(RefField));
+  auto DerefOperand = expr(ignoringParenCasts(
+      declRefExpr(to(parmVarDecl(equalsBoundNode("parm"))))));
+  auto AssignRHS = expr(ignoringParenCasts(
+      unaryOperator(hasOperatorName("*"), hasUnaryOperand(DerefOperand))));
+
+  auto BinaryOpAssign = binaryOperator(hasOperatorName("="), hasLHS(AssignLHS),
+                                       hasRHS(AssignRHS));
+  auto CXXOperatorCallAssign = cxxOperatorCallExpr(
+      hasOverloadedOperatorName("="), hasLHS(AssignLHS), hasRHS(AssignRHS));
+
+  auto SetBody =
+      compoundStmt(statementCountIs(1),
+                   anyOf(has(BinaryOpAssign), has(CXXOperatorCallAssign)));
+  auto BadSetFunction =
+      cxxMethodDecl(
+          parameterCountIs(1), isPublic(),
----------------
vbvictor wrote:

```suggestion
          parameterCountIs(1),
```
Is `isPublic()` needed here? I thought we would remove any visibility specifiers.
Consider this example https://godbolt.org/z/v35dG5rax, I can call a protected method via inheritance, so protected methods can also be called as public.

https://github.com/llvm/llvm-project/pull/132242