[Issue]: optional.h uses non-member function with `->`

[yxsamliu]

Problem Description

A recent clang change (llvm/llvm-project#90152) revealed a bug in rocThrust develop branch

rocThrust/thrust/optional.h

Line 2756 in f3a28e4

this->construct(std::forward<Args>(args)...);

rocThrust/thrust/../thrust/optional.h:2756:11: error: no member named 'construct' in 'optional<type-parameter-0-0 &>'

In this->construct, the arrow operator cannot be overloaded, therefore it can only access its own member function. However, construct is not its member function, since optional<T &> does not define construct. Although optional<T> inherits construct from its base classes, its member construct is not inherited by optional<T &> since they do not have inherit relation.

Since optional<T &> behaves like a delegate of its member m_value, my guess of intention of this->construct is to
perform m_value->construct, i.e., using the overloaded arrow operator. To make the arrow operator taking effect, (*this)-> can be used. Therefor, the fix is

(*this)->construct(std::forward<Args>(args)...);

Operating System

Ubuntu 22.04

CPU

any

GPU

AMD Radeon Pro W7900

ROCm Version

ROCm 6.1.0

ROCm Component

No response

Steps to Reproduce

No response

(Optional for Linux users) Output of /opt/rocm/bin/rocminfo --support

No response

Additional Information

No response

[Snektron]

Hi, thanks for the detailed report. Upon further investigation we realized that the entire use of construct() doesn't really make sense in optional<T&>::emplace(), and that it should change the stored address instead. This issue is actually also present in upstream CCCL, and so that is the proper place to fix it.

I will work with CCCL to get it resolved, after which we can cherry pick the same change onto rocThrust.

[yxsamliu]

Is it possible to add a quick workaround since rocThrust is part of our internal CI and this issue is blocking compiler promotion.

[Snektron]

Sure, I'll make a similar PR on rocThrust momentarily