Undefined reference to `__rust_dealloc`/ `__rust_alloc` when crate-type is ["staticlib", "dylib"]

[mosyp]

Problem
A part of Cargo.toml:

[lib]
name = "my_lib"
crate-type = ["rlib", "staticlib", "dylib"]

When I build these rust artifact and try to link to it within c program I get a lot of undefined reference to '__rust_dealloc' / '__rust_alloc'. For example, the output of :

/usr/bin/ld: libmy_lib.a(std-52f862a21e09568c.std.6as1l5rw-cgu.0.rcgu.o): in function `alloc::alloc::alloc':
/rustc/abe02cefd6cd1916df62ad7dc80161bea50b72e8/src/liballoc/alloc.rs:78: undefined reference to `__rust_alloc'
/usr/bin/ld: libmy_lib.a(std-52f862a21e09568c.std.6as1l5rw-cgu.0.rcgu.o): in function `alloc::alloc::dealloc':
/rustc/abe02cefd6cd1916df62ad7dc80161bea50b72e8/src/liballoc/alloc.rs:96: undefined reference to `__rust_dealloc'
/usr/bin/ld: /rustc/abe02cefd6cd1916df62ad7dc80161bea50b72e8/src/liballoc/alloc.rs:96: undefined reference to `__rust_dealloc'

Compiling c code as gcc main.c my_lib.a -lm -ldl ....

But once I remove a dylib from Cargo.toml, it complies correctly with a success

Notes

Actually I don't need "dylib" for a linux development, but do need for windows. However I couldn't do something like [target.'cfg(windows)'.lib] (as for dependencies)

Output of cargo version:

cargo 1.31.0 (339d9f9c8 2018-11-16)

[alexcrichton]

Thanks for the report! I transferred this to the rust-lang/rust repository as this is a compiler bug rather than a Cargo bug, but perhaps you intended to have the cdylib crate type instead of the dylib crate type?

[bjorn3]

Can you provide an MCVE for this issue? Parts of rustc are built as dylib, so this should work just fine.

[jackh726]

Closing since I think this will be very hard (if not impossible) to reproduce without some code to start from.