P3573 R0 Contract concerns

[wg21bot]

P3573R0 Contract concerns (Bjarne Stroustrup, Michael Hava, J. Daniel Garcia Sanchez, Ran Regev, Gabriel Dos Reis, John Spicer, J.C. van Winkel, David Vandevoorde, Ville Voutilainen)

[jfbastien]

Contracts were discussed in EWG in Hagenberg on Tuesday, see outcome here: #1648 (comment)