rs_bindings_from_cc/test/function/no_elided_lifetimes/test.rs

// Part of the Crubit project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

use googletest::prelude::*;
use no_elided_lifetimes::*;

#[gtest]
fn test_store_pointer() {
    let mut boxed_int = Box::new(123);

    // Without (human-, or machine-verified) lifetime annotations, passing a
    // pointer (or reference) across FFI boundary is unsafe. The call to
    // `StorePointer` should *not* be possible without an `unsafe` block.
    //
    // Note that if `StorePointer` function was *not* marked as `unsafe`,
    // then Rust Clippy would warn about the code below having an
    // "unnecessary `unsafe` block". Seeing such Clippy warning would
    // indicate a regression.
    unsafe {
        StorePointer(boxed_int.as_mut());
    }
    assert_eq!(123, ReadStoredPointer());

    *boxed_int.as_mut() = 456;
    assert_eq!(456, ReadStoredPointer());

    // The commented-out `ReadStoredPointer()` would dereference a dangling
    // pointer, resulting in Undefined Behavior (UB). In normal builds, UB
    // might result in `ReadStoredPointer()` returning 0. In ASan builds,
    // the UB would be caught and reported as an error.
    drop(boxed_int);
    //assert_eq!(456, ReadStoredPointer());
}