[clang] [clang][ASTImporter] Improve structural equivalence of overloadable operators. (PR #72242)

[via cfe-commits]

================
@@ -437,12 +439,67 @@ class StmtComparer {
 };
 } // namespace
 
+static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
+                                     const UnaryOperator *E1,
+                                     const CXXOperatorCallExpr *E2) {
+  return UnaryOperator::getOverloadedOperator(E1->getOpcode()) ==
+             E2->getOperator() &&
+         IsStructurallyEquivalent(Context, E1->getSubExpr(), E2->getArg(0));
+}
+
+static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
+                                     const CXXOperatorCallExpr *E1,
+                                     const UnaryOperator *E2) {
+  return E1->getOperator() ==
+             UnaryOperator::getOverloadedOperator(E2->getOpcode()) &&
+         IsStructurallyEquivalent(Context, E1->getArg(0), E2->getSubExpr());
+}
+
+static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
+                                     const BinaryOperator *E1,
+                                     const CXXOperatorCallExpr *E2) {
+  return BinaryOperator::getOverloadedOperator(E1->getOpcode()) ==
+             E2->getOperator() &&
+         IsStructurallyEquivalent(Context, E1->getLHS(), E2->getArg(0)) &&
+         IsStructurallyEquivalent(Context, E1->getRHS(), E2->getArg(1));
+}
+
+static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
+                                     const CXXOperatorCallExpr *E1,
+                                     const BinaryOperator *E2) {
+  return E1->getOperator() ==
+             BinaryOperator::getOverloadedOperator(E2->getOpcode()) &&
+         IsStructurallyEquivalent(Context, E1->getArg(0), E2->getLHS()) &&
+         IsStructurallyEquivalent(Context, E1->getArg(1), E2->getRHS());
+}
+
 /// Determine structural equivalence of two statements.
 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
                                      const Stmt *S1, const Stmt *S2) {
   if (!S1 || !S2)
     return S1 == S2;
 
+  // Check for statements with similar syntax but different AST.
+  // The unary and binary operators (like '+', '&') can be parsed as
+  // CXXOperatorCall too (and UnaryOperator or BinaryOperator).
+  // This depends on arguments with unresolved type and on the name lookup.
----------------
DonatNagyE wrote:

Thanks for the link, it's really helpful. Perhaps it should be included in the source code comment as well, to help those who'll work on this code in the future.

https://github.com/llvm/llvm-project/pull/72242