DIP 1021--Argument Ownership and Function Calls--Community Review Round 1

[Mike Parker]

This is the feedback thread for the first round of Community 
Review for DIP 1021, "Argument Ownership and Function Calls":

https://github.com/dlang/DIPs/blob/793f83911fdc8c88c6ef34e6a36b5e11e3e574e5/DIPs/DIP1021.md

All review-related feedback on and discussion of the DIP should 
occur in this thread. The review period will end at 11:59 PM ET 
on July 30, or when I make a post declaring it complete.

At the end of Round 2, if further review is deemed necessary, the 
DIP will be scheduled for another round of Community Review. 
Otherwise, it will be queued for the Final Review and Formal 
Assessment.

For some additional context on this DIP, please see Walter's 
latest post on the D Blog titled "Ownership and Borrowing in D":

https://dlang.org/blog/2019/07/15/ownership-and-borrowing-in-d/

But *please do not discuss the blog post or its topic in this 
thread*! Use my post in the Announce forum for that:

https://forum.dlang.org/post/hetwxvibgqcmoltvnoda@forum.dlang.org

Anyone intending to post feedback in this thread is expected to 
be familiar with the reviewer guidelines:

https://github.com/dlang/DIPs/blob/master/docs/guidelines-reviewers.md

I will be moving (copying, deleting, and pasting in a new thread) 
posts that do not adhere to the reviewer guidelines. So please 
keep all comments in this thread focused on DIP 1021.

Thanks in advance to all who participate.