no_init() triggers rchk errors

[krlmlr]

Example package: https://github.com/krlmlr/RcppNoInitTest.

When using no_init() for declaring a variable with assignment, rchk (with clang 6.0 on Ubuntu 18.04) detects an error. This goes away if no_init() is used in a copy constructor.

IntegerVector ret_bad = no_init(1); // rchk detects problem
IntegerVector ret_ok(no_init(1)); // rchk detects no problem

I have created a test package to replicate the problem.

• krlmlr/RcppNoInitTest@6856fbc: First syntax, rchk sees a problem, see .bcheck file
• krlmlr/RcppNoInitTest@6e77a95: Second syntax, this particular rchk problem goes away (but still plenty of other problems)
• krlmlr/RcppNoInitTest@1c3af74: First syntax with Rcpp patch https://github.com/krlmlr/Rcpp/commit/5dbfca11da325a8e72a49b90ccdd1e8714f4089c, this particular rchk problem seems resolved
• krlmlr/RcppNoInitTest@38aa117: Resolving more false positives with Rcpp patch https://github.com/krlmlr/Rcpp/commit/4c4721aab4777fb60592511bbe571b98b1270bee

This is important to me, because dplyr on CRAN shows these rchk errors: https://raw.githubusercontent.com/kalibera/cran-checks/master/rchk/results/dplyr.out.

I'll submit a PR for discussion pointing to this issue. Please advise.

[eddelbuettel]

Taken care of by #893. Thanks!