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//! Regression test for issue #1399
//!
//! This tests that the compiler's last-use analysis correctly handles variables
//! that are captured by closures (upvars). The original issue was that the analysis
//! would incorrectly optimize variable usage as "last use" and perform moves, even when
//! the variable was later needed by a closure that captured it.
//!
//! See: https://github.com/rust-lang/rust/issues/1399
//@ run-pass
struct A {
_a: Box<isize>,
}
fn foo() -> Box<dyn FnMut() -> isize + 'static> {
let k: Box<_> = Box::new(22);
// This use of k.clone() should not be treated as a "last use"
// even though the closure below doesn't actually capture k
let _u = A { _a: k.clone() };
// The closure doesn't actually use k, but the analyzer needs to handle
// the potential capture scenario correctly
let result = || 22;
Box::new(result)
}
pub fn main() {
assert_eq!(foo()(), 22);
}
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