P1494 R5 Partial program correctness

[wg21bot]

P1494R0 Partial program correctness (S. Davis Herring)

[jensmaurer]

This seems to be EWG territory first.

[tituswinters]

Seems to be EWG territory, not library.

[opensdh]

@tituswinters: It does add a library function. I make no claim that the name is so good that LEWG doesn't want to change it. That said, surely EWG should see it first.

[opensdh]

Given recent news, I should point out that it is useful in the absence of contracts.

[opensdh]

@jensmaurer: Should this in fact be closed (given my previous comment)?