[range.common.overview] Removing redundant requirement of views​::​all(E) to be well-formed

[hewillk]

This is consistent with [range.as.rvalue.overview]. Is this editorial?

[jensmaurer]

@jwakely , any opinion here?

[tkoeppe]

@hewillk Please rebase.

[tkoeppe]

Also @CaseyCarter?

[tkoeppe]

@jwakely Ping?

[CaseyCarter]

A common_range is not necessarily an input_range, so I don't think the suggested change is "consistent with [range.as.rvalue.overview]". I don't immediately see if common_range<decltype((E))> implies that views::all(E) is well-formed, so I'd say this is not editorial.

[hewillk]

A common_range is not necessarily an input_range, so I don't think the suggested change is "consistent with [range.as.rvalue.overview]".

That's true for now, but LWG 4083 didn't exist when I submitted this PR.

[tkoeppe]

Thanks, @CaseyCarter! Let's close this then, and @hewillk please submit an LWG issue if you think this needs to be changed.