[PATCH] D134286: [C2x] implement typeof and typeof_unqual

[Matheus Izvekov via Phabricator via cfe-commits]

mizvekov added inline comments.


================
Comment at: clang/lib/AST/ASTContext.cpp:12910-12916
+    // FIXME:: is this assumption correct or do we need to do work here to find
+    // the common type sugar regarding the stripped qualifiers if only one side
+    // is unqual?
+    assert(cast<TypeOfType>(X)->isUnqual() == cast<TypeOfType>(Y)->isUnqual() &&
+           "typeof vs typeof_unqual mismatch?");
+    return Ctx.getTypeOfType(Ctx.getQualifiedType(Underlying),
+                             cast<TypeOfType>(X)->isUnqual());
----------------
mizvekov wrote:
> erichkeane wrote:
> > I'm unfamiliar with this function, but I would expect you MIGHT need to?  If only because they are the same AST node.  Should 'unqual' version be its own node?  I'm on the fence, as it is a LOT of code to do so, but also ends up being simpler in many places.
> A qualified and an unqualified typeof could have the same underlying type, so this assert can trip.
> 
> I think what makes most sense is to unify them to a qualified typeof in case they differ, as that holds the underlying type unchanged:
> ```
>     return Ctx.getTypeOfType(Ctx.getQualifiedType(Underlying),
>                              cast<TypeOfType>(X)->isUnqual() && cast<TypeOfType>(Y)->isUnqual());
> ```
By the way, one thing to notice is the confusion regarding what is the underlying type of this node, the result of `desugar()` or the result of `getUnderlyingType()`?

On my previous post, I meant the former.

Maybe this is a good reason to rename `getUnderlyingType()` to `getUnmodifiedType()` or something similar?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D134286/new/

https://reviews.llvm.org/D134286