#[link_args] is not propagated from libraries to binaries

[whitequark]

To reproduce:

// foo.rs
#![feature(link_args)]
#[link_args = "-Wl,-just_die"]
extern {}

// main.rs
extern crate foo;
fn main() {}

Build with:

rustc foo.rs --crate-type lib
rustc main.rs -L .

This successfully builds (and it shouldn't, if it would pass the -Wl,-just_die). (--verbose is not usable here because of #36175). If I replace #[link_args] with e.g. #[link(name = "just_die")] then the linker invocation fails, so I believe this is a bug with link_args.

[whitequark]

My particular use case is a library that includes DWARF unwinding info that crashes ld64, so I need to be able to include #[link_args = "-Wl,-no_compact_unwind"] in the library to work around that, otherwise it has to be manually inserted into every binary crate.

[japaric]

How this propagation mechanism should work is an unresolved question of the issue that's tracking the stabilization of this link_args feature. cf. #29596 (comment)

[alexcrichton]

This is an intentional design decision of #![link_args], and is one of the reasons it's not generally suitable for passing linker arguments. This "feature" has basically always been slated for deprecation/removal.

[whitequark]

@alexcrichton ack, closing then. I assume that once lld gets integrated into rustc this goes away / gets turned into proper attributes, though the situation might be worse for thrid-party Rust compilers...