[clang] [RFC] Initial implementation of P2719 (PR #113510)

[Matheus Izvekov via cfe-commits]

================
@@ -16439,33 +16735,70 @@ CheckOperatorDeleteDeclaration(Sema &SemaRef, FunctionDecl *FnDecl) {
     return true;
 
   auto *MD = dyn_cast<CXXMethodDecl>(FnDecl);
+  auto ConstructDestroyingDeleteAddressType = [&]() {
+    assert(MD);
+    return SemaRef.Context.getCanonicalType(SemaRef.Context.getPointerType(
+        SemaRef.Context.getRecordType(MD->getParent())));
+  };
+
+  // C++ P2719: A destroying operator delete cannot be type aware
+  // so for QoL we actually check for this explicitly by considering
+  // an destroying-delete appropriate address type and the presence of
+  // any parameter of type destroying_delete_t as an erroneous attempt
+  // to declare a type aware destroying delete, rather than emitting a
+  // pile of incorrect parameter type errors.
+  if (MD && IsPotentiallyTypeAwareOperatorNewOrDelete(
+                SemaRef, MD, /*WasMalformed=*/nullptr)) {
+    QualType AddressParamType =
+        SemaRef.Context.getCanonicalType(MD->getParamDecl(1)->getType());
+    if (AddressParamType != SemaRef.Context.VoidPtrTy &&
+        AddressParamType == ConstructDestroyingDeleteAddressType()) {
+      // The address parameter type implies an author trying to construct a
+      // type aware destroying delete, so we'll see if we can find a parameter
+      // of type `std::destroying_delete_t`, and if we find it we'll report
+      // this as being an attempt at a type aware destroying delete just stop
+      // here. If we don't do this, the resulting incorrect parameter ordering
+      // results in a pile mismatched argument type errors that don't explain
+      // the core problem.
+      for (auto Param : MD->parameters()) {
+        if (isDestroyingDeleteT(Param->getType())) {
+          SemaRef.Diag(MD->getLocation(),
+                       diag::err_type_aware_destroying_operator_delete)
+              << Param->getLocation();
----------------
mizvekov wrote:

```suggestion
          SemaRef.Diag(MD->getLocation(),
                       diag::err_type_aware_destroying_operator_delete)
              << Param->getSourceRange();
```

https://github.com/llvm/llvm-project/pull/113510