[thrust] Fix missing qualifiers for basic_common_reference

[miscco]

If a tuple is compatible with tuple_of_iterator_references we want to treat it as if it had the same types as the tuple

However, we need to also consider the qualifiers

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• thrust/thrust/iterator/detail/tuple_of_iterator_references.h

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Summary

This PR fixes missing cv/ref qualifier handling for cuda::std::basic_common_reference when treating THRUST_NS_QUALIFIER::detail::tuple_of_iterator_references as compatible with cuda::std::tuple. Instead of constructing qualified tuple element types directly, the two partial specializations now delegate to basic_common_reference instantiated on the corresponding unadorned tuple types with the original qualifier helpers. The implementation is simplified and an explanatory comment was added.

Changes

File: thrust/thrust/iterator/detail/tuple_of_iterator_references.h

• Reworked two partial specializations of cuda::std::basic_common_reference that handle compatibility between tuple_of_iterator_references<...> and tuple<...>:
  • Replaced direct formation of tuple<_TQual<_TTypes>...> / tuple<_UQual<_UTypes>...> with inheritance from basic_common_reference< tuple<_...>, tuple<_...>, _TQual, _UQual >. This ensures qualifiers are considered when computing element-wise common reference types.
  • Adjusted the enable_if_t compatibility condition to use unqualified tuple<...> type expressions.
  • Simplified implementation and added an explanatory comment.

Impact

Correctly accounts for cv/ref qualifiers when computing common reference types for tuples compatible with tuple_of_iterator_references, preventing incorrect/common-missed qualifier propagation and improving type correctness in generic tuple reference resolution.

suggestion:

Walkthrough

Two partial specializations of cuda::std::basic_common_reference in tuple_of_iterator_references.h now delegate their resulting type to basic_common_reference instantiated on the corresponding plain tuple<...> types and use unqualified tuple<...> in the enable_if compatibility checks.

Changes

Common Reference Delegation

Layer / File(s)	Summary
basic_common_reference specializations thrust/thrust/iterator/detail/tuple_of_iterator_references.h	Both basic_common_reference<tuple_of_iterator_references, tuple> and basic_common_reference<tuple, tuple_of_iterator_references> specializations now inherit their type from basic_common_reference<tuple<...>, tuple<...>, _TQual, _UQual> and use unqualified tuple<...> expressions in their enable_if_t conditions.

Possibly related PRs

• NVIDIA/cccl#9261: Earlier PR modifying the same basic_common_reference handling for tuple_of_iterator_references and cuda::std::tuple type computation.

Suggested reviewers

• ericniebler
• elstehle

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• thrust/thrust/iterator/detail/tuple_of_iterator_references.h

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