Nightly regression: downstream artifacts suddenly depend on `proc-macro` crate's dylib

[alexbool]

Consider a project:

.
├── Cargo.lock
├── Cargo.toml
├── library
│   ├── Cargo.toml
│   └── src
│       └── lib.rs
└── user
    ├── Cargo.toml
    └── src
        └── lib.rs

./Cargo.toml:

[workspace]
members = ["user", "library"]

library/Cargo.toml:

[package]
name = "library"
version = "0.1.0"
authors = ["Alexander Bulaev <alexbool@yandex-team.ru>"]

[dependencies]
serde_derive = "*"

library/src/lib.rs:

extern crate serde_derive;

user/Cargo.toml:

[package]
name = "user"
version = "0.1.0"
authors = ["Alexander Bulaev <alexbool@yandex-team.ru>"]

[lib]
crate-type = ["rlib", "dylib"]

[dependencies]
library = { path = "../library" }
serde_derive = "*"

user/src/lib.rs:

extern crate library;
extern crate serde_derive;

Then:

alexbool@alexbool-osx ~/D/I/r/user> cargo build
   Compiling quote v0.3.5
   Compiling unicode-xid v0.0.3
   Compiling syn v0.10.3
   Compiling serde_codegen_internals v0.11.1
   Compiling serde_codegen v0.8.18
   Compiling serde_derive v0.8.18
   Compiling library v0.1.0 (file:///Users/alexbool/Documents/IdeaProjects/rust-fail/library)
warning: custom derive crates and `#[no_link]` crates have no effect without `#[macro_use]`
 --> /Users/alexbool/Documents/IdeaProjects/rust-fail/library/src/lib.rs:1:1
  |
1 | extern crate serde_derive;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^

   Compiling user v0.1.0 (file:///Users/alexbool/Documents/IdeaProjects/rust-fail/user)
    Finished debug [unoptimized + debuginfo] target(s) in 13.74 secs


alexbool@alexbool-osx ~/D/I/r/user> otool -L ../target/debug/libuser.dylib 
../target/debug/libuser.dylib:
	/Users/alexbool/Documents/IdeaProjects/rust-fail/target/debug/deps/libuser.dylib (compatibility version 0.0.0, current version 0.0.0)
	@rpath/libstd-1357b93f.dylib (compatibility version 0.0.0, current version 0.0.0)
	/Users/alexbool/Documents/IdeaProjects/rust-fail/target/debug/deps/libserde_derive-7dacf7ca26e124d8.dylib (compatibility version 0.0.0, current version 0.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1238.0.0)

Whoa! This artifact depends on libserde_derive-7dacf7ca26e124d8.dylib and libstd-1357b93f.dylib.

If you try staticlib, you get an error:

   Compiling user v0.1.0 (file:///Users/alexbool/Documents/IdeaProjects/rust-fail/user)
error: dependency `serde_derive` not found in rlib format

error: aborting due to previous error

error: Could not compile `user`.

If you try a binary, it compiles but obviously cannot be run:

alexbool@alexbool-osx ~/D/I/r/user> ../target/debug/user 
dyld: Library not loaded: @rpath/libstd-1357b93f.dylib
  Referenced from: /Users/alexbool/Documents/IdeaProjects/rust-fail/user/../target/debug/user
  Reason: image not found
fish: '../target/debug/user' terminated by signal SIGABRT (Abort)

Meta:
macOS Sierra

alexbool@alexbool-osx ~> rustc -vV
rustc 1.15.0-nightly (ac635aa95 2016-11-18)
binary: rustc
commit-hash: ac635aa95ba851898e125b047ad7b8d6a8fecf8e
commit-date: 2016-11-18
host: x86_64-apple-darwin
release: 1.15.0-nightly
LLVM version: 3.9
alexbool@alexbool-osx ~> cargo --version
cargo 0.16.0-nightly (d1bfc01 2016-11-18)

Also reproduces on Windows i686 msvc.

[alexbool]

cc @jseyfried

[jseyfried]

@alexbool Thanks for the report, fixed in #37895.

As we wait for that to land, you can work around this issue by reordering the extern crates in user/src/lib.rs so that proc-macro crates precede other crates.

[alexbool]

@jseyfried thanks!