[PATCH] D55662: [Sema][ObjC] Do not warn about repeated uses of weak variables when the variables are accessed in an unevaluated context.

Akira Hatanaka via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Thu Dec 20 21:39:38 PST 2018

ahatanak added a comment.

In D55662#1337141 <https://reviews.llvm.org/D55662#1337141>, @rjmccall wrote:

> In D55662#1336835 <https://reviews.llvm.org/D55662#1336835>, @ahatanak wrote:
> > In D55662#1335773 <https://reviews.llvm.org/D55662#1335773>, @rjmccall wrote:
> >
> > > Okay.  You may need to push an unevaluated context when doing that.
> >
> >
> > Since I'm just moving the call to `CheckPlaceholderExpr` to the call site, I don't think I have to push an unevaluated context there?
> Hmm.  Right, for the `auto` inference specifically it's fine because the expression is in fact evaluated: we're not just eliminating placeholders in order to resolve `decltype`, we're eliminating placeholders to actually figure out what's going on with the initialization.

clang currently diagnose the repeated use of weak in the following case (with or without this patch):

  auto __weak wp = b.weakProp; 

I find this counterintuitive, but I guess this is the expected behavior?

  rC Clang



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