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//@ run-fail
//@ compile-flags: -Zcontract-checks=yes
#![feature(contracts)]
//~^ WARN the feature `contracts` is incomplete and may not be safe to use and/or cause compiler crashes [incomplete_features]
struct Baz {
baz: i32
}
#[track_caller]
#[core::contracts::requires(x.baz > 0)]
#[core::contracts::ensures({let old = x.baz; move |ret:&Baz| ret.baz == old*2 })]
// Relevant thing is this: ^^^^^^^^^^^^^^^
// because we are capturing state that is Copy
fn doubler(x: Baz) -> Baz {
Baz { baz: x.baz + 10 }
}
fn main() {
assert_eq!(doubler(Baz { baz: 10 }).baz, 20);
assert_eq!(doubler(Baz { baz: 100 }).baz, 200);
// This is a *run-fail* test because it is still exercising the
// contract machinery, specifically because this second invocation
// of `doubler` shows how the code does not meet its contract.
}
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