[abaines]

I feel as though they should change the name of the paper, because this must be one of the most complex takes on 'defer' that I have seen.

They make a classic mistake of trying to solve a problem by adding more complexity. They cannot decide on by-value or by-reference, so they take the convoluted C++ syntax to allow specifying one (as well as other semantics?).

It does not fit with C in my opinion. It will also hurt third party tools that wish to understand C source code, because they must inherit this complexity.

I would prefer a solution where they simply pick one (by ref / by value) and issue a compiler warning if the programmer has misunderstood. For example, pick by-value and issue a warning if a variable used inside the defer is reassigned later in the scope.

[tedunangst]

I think people are getting hung up on the lambda syntax, but it seems they're just taking what they're given. If c23 adds lambdas, at this point I'd say it's more likely to be c++ syntax than c syntax because c++ is already out there. So instead of "to resolve ambiguity we force user to choose" it's more like "the probable lambda syntax already makes this explicit so we will use it too." I think that makes more sense than two different syntaxes for lambda and defer, whatever the other merits of the proposal.