NoQ added a comment.
Thank you!! I think we're almost ready to commit but this concern is still
hanging:
> I see that the patch doesn't touch `handleFixableVariable()`. Do we still
> attach fixits to the warning, or did we already change it to be attached to a
> note associated with the warning? Because fixits with placeholders aren't
> allowed on warnings, we should make sure it's attached to note before landing
> this patch.
================
Comment at: clang/lib/Analysis/UnsafeBufferUsage.cpp:780-781
+ } else {
+ // In cases `Init` is of the form `&Var` after stripping of implicit
+ // casts, where `&` is the built-in operator, the extent is 1.
+ if (auto AddrOfExpr = dyn_cast<UnaryOperator>(Init->IgnoreImpCasts()))
----------------
ziqingluo-90 wrote:
> NoQ wrote:
> > ```lang=c
> > int x = 1;
> > char *ptr = &x; // std::span<char> ptr { &x, 4 };
> > ```
> > This is valid code. I suspect we want to check types as well, to see that
> > type sizes match.
> >
> > Most of the time code like this violates strict aliasing, but `char` is
> > exceptional, and even if it did violate strict aliasing, people can compile
> > with `-fno-strict-aliasing` to define away the UB, so we have to respect
> > that.
> This code is not valid in C++. An explicit cast is needed in front of `&x`.
> I will add a test to show that
>
> ```
> int x = 1;
> char * ptr = (char *)&x;
> ```
> will have a place holder for the span size.
Yes you're right! It's only valid in C where these fixits don't apply.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D139737/new/
https://reviews.llvm.org/D139737
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