LLVM assertion when compiling with -g

[Kintaro]

@bstrie So, this code raises an assertion in llvm when compiling with -g. Without -g it works fine.

#![feature(unboxed_closures)]

pub struct A;

impl A {
    pub fn foo(&self, f: Box<Fn<(), ()> + 'static>) ->
            Box<Fn<(), ()> + 'static> {
        (box move |&:| {
            (*f).call(())
        })
    }
}

Raised assertion is

rustc: /home/rustbuild/src/rust-buildbot/slave/nightly-linux/build/src/llvm/lib/IR/Instructions.cpp:1086: void llvm::StoreInst::AssertOK(): Assertion `getOperand(0)->getType() == cast<PointerType>(getOperand(1)->getType())->getElementType() && "Ptr must be a pointer to Val type!"' failed.
[1]    1800 abort (core dumped)  rustc --crate-type lib test.rs -g

Edit: reduced code more

[japaric]

Duplicate of #17257? (there are some comments with unboxed closures and -g/--debuginfo)

[Kintaro]

It worked with the rustc versions from around last week. Especially the rustup versions.
A friend just tested it with his "old" version from 11/26, and it still works there.

So either it's new or it's a regression bug.

[luqmana]

cc @michaelwoerister

[michaelwoerister]

I'll look into it.

[Kintaro]

I suspect the culprit is make_return_slot_pointer in librustc_trans::trans::builder