[clang-tools-extra] [clang-tidy] `doesNotMutateObject`: Handle calls to member functions … (PR #94362)

[Felix Berger via cfe-commits]

================
@@ -36,6 +36,111 @@ void extractNodesByIdTo(ArrayRef<BoundNodes> Matches, StringRef ID,
     Nodes.insert(Match.getNodeAs<Node>(ID));
 }
 
+// If `D` has a const-qualified overload with otherwise identical
+// ref-qualifiers, returns that overload.
+const CXXMethodDecl *findConstOverload(const CXXMethodDecl &D) {
+  assert(!D.isConst());
+
+  DeclContext::lookup_result lookup_result =
+      D.getParent()->lookup(D.getNameInfo().getName());
+  if (lookup_result.isSingleResult()) {
+    // No overload.
+    return nullptr;
+  }
+  for (const Decl *overload : lookup_result) {
+    const CXXMethodDecl *candidate = dyn_cast<CXXMethodDecl>(overload);
+    if (candidate && !candidate->isDeleted() && candidate->isConst() &&
+        candidate->getRefQualifier() == D.getRefQualifier()) {
----------------
fberger wrote:

It looks like we look up by name, do we also need to confirm that the return types are the same, or would overloading otherwise not be allowed and that's why it's implied?

https://github.com/llvm/llvm-project/pull/94362