mizvekov added a comment. In D100713#2759637 <https://reviews.llvm.org/D100713#2759637>, @aaronpuchert wrote:
> Again, I'm not sure if it helps to use `getDecltypeForParenthesizedExpr` > where we don't actually have the `decltype` of a parenthesized expression. > > It's probably not entirely coincidental, but things aren't defined this way. The current situation with `getDecltypeForParenthesizedExpr` is that it already is used in some places where there is no decltype of a parenthesized expression either. This function is a bit new, I introduced it in D98160 <https://reviews.llvm.org/D98160>. I think the mnemonic is OK, but this is the best I could come up at the time. If you have better suggestions, I am all for it. In the above patch, this is introduced to help out with the type for the expression in a compound requires (http://eel.is/c++draft/expr.prim.req.compound#1.3.2). But then it is also used in the implementation of decltype itself, where it kicks in even for non-parenthesized expressions (if the expression is not otherwise a special case, as defined in https://eel.is/c++draft/dcl.type.decltype#1). I think the standard just missed giving a name to this pattern, and it otherwise IMHO misses the mark by using something more complex to explain something simpler. I think it's no coincidence that for the patch I am working on, I had to change all of these copies in exactly the same way :) ================ Comment at: clang/lib/Sema/SemaExprCXX.cpp:5845 + if (!To->isRValue()) { + QualType T = Self.Context.getDecltypeForParenthesizedExpr(To); InitializedEntity Entity = InitializedEntity::InitializeTemporary(T); ---------------- aaronpuchert wrote: > mizvekov wrote: > > aaronpuchert wrote: > > > The quote doesn't reference parenthesized expressions, isn't this just > > > coincidentally the same thing? > > It's fundamentally the same thing. The `getDecltypeForParenthesizedExpr` > > name is what I tried to keep, I don't have better ideas there. > What this is doing is pointwise equal to `getDecltypeForParenthesizedExpr`, > but there is no parenthesized expression, and no `decltype`. There is a quote > from the standard that defines this separately (by now this seems to be > [[http://eel.is/c++draft/expr.cond#4|expr.cond#4]]), and there are some > differences especially in the prvalue case. So I'm not sure this helps. Here for XValue and and LValue, the rules are exactly the same as https://eel.is/c++draft/dcl.type.decltype#1. And the original code here even already special cases it... I am sure there is some way we can agree that we should not repeat the code just because the standard did not bother to give a name to this part of the rules... And again I think it is no coincidence that it makes sense to perform the same changes in all these cases. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D100713/new/ https://reviews.llvm.org/D100713 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
