rust/tests/rustdoc/issue-54478-demo-allocator.rs
2023-01-11 09:32:08 +00:00

43 lines
1.1 KiB
Rust

// Issue #54478: regression test showing that we can demonstrate
// `#[global_allocator]` in code blocks built by `rustdoc`.
//
// ## Background
//
// Changes in lang-item visibility injected failures that were only
// exposed when compiling with `-C prefer-dynamic`. But `rustdoc` used
// `-C prefer-dynamic` (and had done so for years, for reasons we did
// not document at that time).
//
// Rather than try to revise the visbility semanics, we instead
// decided to change `rustdoc` to behave more like the compiler's
// default setting, by leaving off `-C prefer-dynamic`.
// compile-flags:--test
//! This is a doc comment
//!
//! ```rust
//! use std::alloc::*;
//!
//! #[global_allocator]
//! static ALLOC: A = A;
//!
//! static mut HIT: bool = false;
//!
//! struct A;
//!
//! unsafe impl GlobalAlloc for A {
//! unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
//! HIT = true;
//! System.alloc(layout)
//! }
//! unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
//! System.dealloc(ptr, layout);
//! }
//! }
//!
//! fn main() {
//! assert!(unsafe { HIT });
//! }
//! ```