Quuxplusone marked 2 inline comments as done.
Quuxplusone added inline comments.
================
Comment at: clang/lib/Sema/SemaStmt.cpp:3095
- // ...non-volatile...
- if (VD->getType().isVolatileQualified())
- return false;
-
- // C++20 [class.copy.elision]p3:
- // ...rvalue reference to a non-volatile...
- if (VD->getType()->isRValueReferenceType() &&
- (!(CESK & CES_AllowRValueReferenceType) ||
- VD->getType().getNonReferenceType().isVolatileQualified()))
+ if (VD->getType()->isObjectType()) {
+ // C++17 [class.copy.elision]p3:
----------------
mizvekov wrote:
> mizvekov wrote:
> > mizvekov wrote:
> > > A drive by fix here would be that we already have a VDType in this
> > > context, might as well use it even though original for some reason missed
> > > it in this part.
> > This whole block is also logically equivalent to the much simpler:
> > ```
> > if (VDType.isReferenceType()) {
> > if (!(CESK & CES_AllowRValueReferenceType) ||
> > !VDType.isRValueReferenceType())
> > return false;
> > VDType = VDType.getNonReferenceType()
> > }
> > if (!VDType.isObjectType() || VDType.isVolatileQualified())
> > return false;
> > ```
> > But you do have to adjust the comments there and adjust the rest to use
> > VDType consistently :)
> > Also, I think it might be possible to even remove the
> > `!VDType.isObjectType() || ` part from my suggestion above, because it
> > might be the only option left if it is not a reference anyway.
> ```
> bool isObjectType() const {
> // C++ [basic.types]p8:
> // An object type is a (possibly cv-qualified) type that is not a
> // function type, not a reference type, and not a void type.
> return !isReferenceType() && !isFunctionType() && !isVoidType();
> }
> ```
> So yeah I think you can just make my suggestion be:
> ```
> if (VDType.isReferenceType()) {
> if (!(CESK & CES_AllowRValueReferenceType) ||
> !VDType.isRValueReferenceType())
> return false;
> VDType = VDType.getNonReferenceType()
> }
> if (VDType.isVolatileQualified())
> return false;
> ```
>
>
Yeah but I //reaally// don't want to
(1) change the meaning of `VDType` in the middle of this function (mantra: "one
name = one meaning")
(2) get "clever". I don't want to have to think about "Are there any types that
are neither object types nor reference types?" (What about function types? What
about block types? What about, I dunno, bit-fields?) I want the code to be
//obviously correct//, and also to casewise match exactly what the standard
says. It says object or rvalue reference type — let's write code that expresses
that wording //exactly//.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D98971/new/
https://reviews.llvm.org/D98971
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