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3666. join_view's difference type is too small

Section: 26.7.12 [range.join] Status: New Submitter: Tomasz Kamiński Opened: 2022-01-30 Last modified: 2022-01-31

Priority: 2

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Despite the fact that join_view may produce more elements than each joined view(s) contains, we require implementations to use the common_type of their difference types (per [range.join.iterator] p3), which may lead to UB. As we already have provided implementation freedom to define extended integer-like types we should make provision for them to be used here as well. The same issue applies to the join_with_view as proposed by P2441.

[2022-03-04; Reflector poll]

Set priority to 2 after reflector poll. Might be a design issue.

Proposed resolution: