// Invariance with respect to a region: // // You cannot convert between regions. struct invariant { f: fn(x: &self/int) -> &self/int } fn to_same_lifetime(bi: invariant/&r) { let bj: invariant/&r = bi; } fn to_shorter_lifetime(bi: invariant/&r) { let bj: invariant/&blk = bi; //~ ERROR mismatched types } fn to_longer_lifetime(bi: invariant/&r) -> invariant/&static { bi //~ ERROR mismatched types } fn main() { }