rust/tests/ui/feature-gates/feature-gate-needs-allocator.rs

#![needs_allocator] //~ ERROR the `#[needs_allocator]` attribute is

fn main() {}
rustc: Allow changing the default allocator This commit is an implementation of [RFC 1183][rfc] which allows swapping out the default allocator on nightly Rust. No new stable surface area should be added as a part of this commit. [rfc]: https://github.com/rust-lang/rfcs/pull/1183 Two new attributes have been added to the compiler: * `#![needs_allocator]` - this is used by liballoc (and likely only liballoc) to indicate that it requires an allocator crate to be in scope. * `#![allocator]` - this is a indicator that the crate is an allocator which can satisfy the `needs_allocator` attribute above. The ABI of the allocator crate is defined to be a set of symbols that implement the standard Rust allocation/deallocation functions. The symbols are not currently checked for exhaustiveness or typechecked. There are also a number of restrictions on these crates: * An allocator crate cannot transitively depend on a crate that is flagged as needing an allocator (e.g. allocator crates can't depend on liballoc). * There can only be one explicitly linked allocator in a final image. * If no allocator is explicitly requested one will be injected on behalf of the compiler. Binaries and Rust dylibs will use jemalloc by default where available and staticlibs/other dylibs will use the system allocator by default. Two allocators are provided by the distribution by default, `alloc_system` and `alloc_jemalloc` which operate as advertised. Closes #27389 2015-06-25 17:07:01 +00:00			#![needs_allocator] //~ ERROR the `#[needs_allocator]` attribute is

			`fn main() {}`