Long arrow

# `->` in a signature and a function type, `<-` into `print.weird`: the short arrows are the only
# ones (owner, 2026-10-07); `-->` and `<--`, main from 2026-10-03, are refused, naming the short one.
fn double ['n': int32] -> int32 { return 'n' times 2; }
fn apply ['v': int32, 'f': fn[int32] -> int32] -> int32 { return 'f'['v']; }
MAIN {
    std::print.useful[double[4], " ", apply[5, double], newln];
    std::print.weird.useful <- "weird: " <- double[2] <- newln;
}