rustc crash when #[no_mangle] function is declared multiple times with different signatures.

[pnkfelix]

(imported from improperly closed bug #18358)

#![allow(dead_code)]

pub mod x {
    #[no_mangle]
    pub fn f() { }
}

pub mod y {
    #[no_mangle]
    pub fn f(_: i32) { }
}

fn main() { }

playpen

This crashes with:

rustc: /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/llvm/include/llvm/Support/Casting.h:237: typename llvm::cast_retty<X, Y*>::ret_type llvm::cast(Y*) [with X = llvm::Function; Y = llvm::Value; typename llvm::cast_retty<X, Y*>::ret_type = llvm::Function*]: Assertion `isa<X>(Val) && "cast<Ty>() argument of incompatible type!"' failed.
Aborted (core dumped)
playpen: application terminated with error code 134
Program ended.

(I don't know what it does if one compiles about LLVM assertions turned on.)

[nagisa]

This doesn’t crash anymore.

test.rs:10:5: 10:25 error: symbol `f` is already defined
test.rs:10     pub fn f(_: i32) { }
               ^~~~~~~~~~~~~~~~~~~~

[pnkfelix]

@nagisa it currently crashes in the playpen, set to "Nightly" ... are you saying its been fixed since the last nightly, but the PR didn't reference this ticket?

[nagisa]

@pnkfelix cases like these are errors (or ICEs, like in #24561) since #23011 has landed.

I think playpen’s nightly might be outdated.

[alexcrichton]

I think @nagisa is right, I get an error on the most recent nightly, co closing. I'll investigate what's up with playpen.