rust/tests/ui/closures/2229_closure_analysis/diagnostics/repr_packed.rs
2023-01-31 20:28:11 +01:00

32 lines
1.0 KiB
Rust

// edition:2021
// Given how the closure desugaring is implemented (at least at the time of writing this test),
// we don't need to truncate the captured path to a reference into a packed-struct if the field
// being referenced will be moved into the closure, since it's safe to move out a field from a
// packed-struct.
//
// However to avoid surprises for the user, or issues when the closure is
// inlined we will truncate the capture to access just the struct regardless of if the field
// might get moved into the closure.
//
// It is possible for someone to try writing the code that relies on the desugaring to create a ref
// into a packed-struct. Here we test that the compiler still detects that case.
fn test_missing_unsafe_warning_on_repr_packed() {
#[repr(packed)]
struct Foo { x: String }
let foo = Foo { x: String::new() };
let c = || {
println!("{}", foo.x);
//~^ ERROR: reference to packed field is unaligned
let _z = foo.x;
};
c();
}
fn main() {
test_missing_unsafe_warning_on_repr_packed();
}