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

[via cfe-commits]

================
@@ -36,6 +36,116 @@ void extractNodesByIdTo(ArrayRef<BoundNodes> Matches, StringRef ID,
     Nodes.insert(Match.getNodeAs<Node>(ID));
 }
 
+// Returns true if both types refer to the same type,
+// ignoring the const-qualifier.
+bool isSameTypeIgnoringConst(QualType A, QualType B) {
+  A = A.getCanonicalType();
+  B = B.getCanonicalType();
+  A.addConst();
+  B.addConst();
+  return A == B;
+}
+
+// Returns true if `D` and `O` have the same parameter types.
+bool hasSameParameterTypes(const CXXMethodDecl &D, const CXXMethodDecl &O) {
+  if (D.getNumParams() != O.getNumParams())
+    return false;
+  for (int I = 0, E = D.getNumParams(); I < E; ++I) {
+    if (!isSameTypeIgnoringConst(D.getParamDecl(I)->getType(),
+                                 O.getParamDecl(I)->getType()))
+      return false;
+  }
+  return true;
+}
+
+// If `D` has a const-qualified overload with otherwise identical
+// ref-qualifiers and parameter types, returns that overload.
+const CXXMethodDecl *findConstOverload(const CXXMethodDecl &D) {
+  assert(!D.isConst());
+
+  DeclContext::lookup_result LookupResult =
+      D.getParent()->lookup(D.getNameInfo().getName());
+  if (LookupResult.isSingleResult()) {
+    // No overload.
+    return nullptr;
+  }
+  for (const Decl *Overload : LookupResult) {
+    const CXXMethodDecl *O = dyn_cast<CXXMethodDecl>(Overload);
----------------
EugeneZelenko wrote:

```suggestion
    const auto *O = dyn_cast<CXXMethodDecl>(Overload);
```

Type is spelled explicitly in same statement.

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