ebevhan added inline comments.
================
Comment at: clang/lib/Sema/SemaChecking.cpp:13384
case Stmt::MemberExprClass: {
expr = cast<MemberExpr>(expr)->getBase();
break;
----------------
ilya wrote:
> rsmith wrote:
> > ilya wrote:
> > > rsmith wrote:
> > > > Hmm, don't we need to do different things for dot and arrow in this
> > > > case?
> > > There are several test cases for an out of bounds access on an array
> > > member using dot and arrow operators in array-bounds.cpp. Do you have a
> > > specific test case for which you think the code is broken?
> > > There are several test cases for an out of bounds access on an array
> > > member using dot and arrow operators in array-bounds.cpp. Do you have a
> > > specific test case for which you think the code is broken?
> >
> > Sure. There's a false negative for this:
> >
> > ```
> > struct A { int n; };
> > A *a[4];
> > int *n = &a[4]->n;
> > ```
> >
> > ... because we incorrectly visit the left-hand side of the `->` with
> > `AllowOnePastEnd == 1`. The left-hand side of `->` is subject to
> > lvalue-to-rvalue conversion, so can't be one-past-the-end regardless of the
> > context in which the `->` appears.
> > ... because we incorrectly visit the left-hand side of the -> with
> > AllowOnePastEnd == 1. The left-hand side of -> is subject to
> > lvalue-to-rvalue conversion, so can't be one-past-the-end regardless of the
> > context in which the -> appears.
>
> Thanks for clarifying. So basically we don't want to allow one-past-end for
> MemberExpr?
> Thanks for clarifying. So basically we don't want to allow one-past-end for
> MemberExpr?
I think the point is rather that when the MemberExpr isArrow, we want to think
of it as performing an implicit dereference first, and thus we should do
`AllowOnePastEnd--` before recursing if that is the case.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D71714/new/
https://reviews.llvm.org/D71714
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