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

[Aaron Ballman via cfe-commits]

================
@@ -16110,6 +16128,127 @@ bool Sema::CompleteConstructorCall(CXXConstructorDecl *Constructor,
   return Invalid;
 }
 
+bool Sema::IsTypeIdentitySpecialization(QualType Type) const {
+  auto *TypeIdentity = getStdTypeIdentity();
+  if (!TypeIdentity)
+    return false;
+  auto *SpecializedDecl = Type->getSpecializedTemplateDecl();
----------------
AaronBallman wrote:

```suggestion
  const auto *TypeIdentity = getStdTypeIdentity();
  if (!TypeIdentity)
    return false;
  const auto *SpecializedDecl = Type->getSpecializedTemplateDecl();
```

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