How to teach the compiler that stop() doesn't return?

[krlmlr]

So that we can write

bool foo(int x) {
  switch (x) {
    case 1: return true;
    case 2: return false;
    default: stop("Don't know this x");
  }
}

without issuing a warning.

There is a "noreturn" attribute for GCC and clang, but there might be other solutions. EDIT: http://stackoverflow.com/a/25408952/946850 is a nice SO answer that features __builtin_unreachable().

Re tidyverse/dplyr#1878 (comment), CC @hadley.

[kevinushey]

For what it's worth, R defines the NORET macro for handling this as well so we could potentially just use that: https://github.com/wch/r-source/blob/trunk/src/include/R_ext/Error.h#L29-L37

[eddelbuettel]

We appear to have issues with this per #512.

@krlmlr @kevinushey Can one of you familiar with NORET please check how / why it is defined? I tried adding a simple

#undef NORET

in the file, but no mas. If and when I do replace NORET with /*NORET*/ then I can build on the old platform.