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

[via cfe-commits]

================
@@ -1095,12 +1095,40 @@ static TypeSourceInfo *getTypeSourceInfoForStdAlignValT(Sema &S,
   return S.Context.getTrivialTypeSourceInfo(StdAlignValDecl);
 }
 
+// When searching for custom allocators on the PromiseType we want to
+// warn that we will ignore type aware allocators.
+static bool DiagnoseTypeAwareAllocatorsIfNecessary(Sema &S, SourceLocation Loc,
+                                                   unsigned DiagnosticID,
+                                                   DeclarationName Name,
+                                                   QualType PromiseType) {
+  if (!S.getLangOpts().TypeAwareAllocators)
+    return false;
+  if (!PromiseType->isRecordType())
+    return false;
+  LookupResult R(S, Name, Loc, Sema::LookupOrdinaryName);
+  S.LookupQualifiedName(R, PromiseType->getAsCXXRecordDecl());
+  bool HaveIssuedWarning = false;
+  for (auto Decl : R) {
+    if (S.isTypeAwareOperatorNewOrDelete(Decl)) {
+      if (!HaveIssuedWarning) {
+        S.Diag(Loc, DiagnosticID) << Name;
+        HaveIssuedWarning = true;
+      }
+      S.Diag(Decl->getLocation(), diag::note_type_aware_operator_declared)
+          << 0 << Decl;
----------------
cor3ntin wrote:

```suggestion
          << /*insert comment here*/ 0 << Decl;
```

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