aaron.ballman added inline comments.
================
Comment at: clang/lib/Sema/SemaInit.cpp:4506
!S.Context.hasSameUnqualifiedType(E->getType(), DestType) &&
- (E->getType()->isIntegralOrEnumerationType() ||
+ (E->getType()->isIntegralOrUnscopedEnumerationType() ||
E->getType()->isFloatingType())) {
----------------
ahatanak wrote:
> ahatanak wrote:
> > aaron.ballman wrote:
> > > ahatanak wrote:
> > > > aaron.ballman wrote:
> > > > > This doesn't match the comments immediately above here and I don't
> > > > > think is the correct fix.
> > > > >
> > > > > We're handling this case: http://eel.is/c++draft/dcl.init.list#3.8
> > > > >
> > > > > A scoped enumeration has a fixed underlying type
> > > > > (https://eel.is/c++draft/dcl.enum#5.sentence-5). The initializer list
> > > > > has a single element and that element can be implicitly converted to
> > > > > the underlying type (`int` in all of the test cases changed in this
> > > > > patch). And this is a direct initialization case, so I think we
> > > > > should be performing the conversion here rather than skipping to the
> > > > > next bullet.
> > > > Can scoped enums be implicitly converted to integer types? Unscoped
> > > > enums can be converted to an integer type, but I don't see any mention
> > > > of scoped enums here: https://eel.is/c++draft/conv.integral
> > > >
> > > > It seems that the original paper was trying to change the rules about
> > > > conversions from the underlying type to a scoped enum. It doesn't look
> > > > like it's allowing conversion from a scope enum to another scope enum.
> > > >
> > > > https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0138r2.pdf
> > > > Can scoped enums be implicitly converted to integer types? Unscoped
> > > > enums can be converted to an integer type, but I don't see any mention
> > > > of scoped enums here: https://eel.is/c++draft/conv.integral
> > >
> > > Correct, they cannot be implicitly converted to an integer.
> > >
> > > > It seems that the original paper was trying to change the rules about
> > > > conversions from the underlying type to a scoped enum. It doesn't look
> > > > like it's allowing conversion from a scope enum to another scope enum.
> > >
> > > Agreed, however, I think where we want this to fail is below in the
> > > attempt at conversion. "v can be implicitly converted to U" is the part
> > > that should be failing here, and we're now skipping over the bit of code
> > > that's checking whether the implicit conversion is valid.
> > Is the code below checking whether the implicit conversion is valid? It
> > looks like it's assuming the implicit conversion is valid and adding an
> > implicit conversion sequence based on that assumption. If the source is an
> > integer, unscoped enum, or floating type, the implicit conversion that is
> > performed later should succeed except when there is narrowing.
> >
> > Or are you suggesting we should add a check to
> > `Sema::PerformImplicitConversion` that rejects conversions from scoped
> > enums to other types? It seems to me that it's better to detect the error
> > earlier.
> Alternatively, we can emit a diagnostic in the code below that specifically
> calls out conversion from scoped enums to integer types.
> Is the code below checking whether the implicit conversion is valid?
It's forming the conversion sequence as-if it must be valid, but that causes us
to get the right diagnostics. We do the same for narrowing float conversions:
https://github.com/llvm/llvm-project/blob/main/clang/lib/Sema/SemaInit.cpp#L4521
and I would expect us to then need changes so we get to here:
https://github.com/llvm/llvm-project/blob/main/clang/lib/Sema/SemaInit.cpp#L8478
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D126084/new/
https://reviews.llvm.org/D126084
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