An option of a generic pointer triggers an LLVM assertion

[lifthrasiir]

Minimal example:

pub trait X { fn f(&self); }
impl X for int { fn f(&self) {} }
pub struct Z<'self>(Option<&'self X>);
pub fn main() { let x = 42; let z = Z(Some(&x as &X)); let _ = z; }

In my Windows machine, it results in:

Assertion failed: (i >= FTy->getNumParams() || FTy->getParamType(i) == Args[i]->getType()) && "Calling a function with a bad signature!", file c:/bot/slave/dist2-win/build/src/llvm/lib/IR/Instructions.cpp, line 281

Reproduced on Rust 0.8 and 0.9-pre (371a7ec). It doesn't seem to be Windows specific either.

[emberian]

Reproduced on Linux.

[klutzy]

Example without Option:

pub enum Enum<T> {
    A(T),
}

pub trait X {}
impl X for int {}

pub struct Z<'self>(Enum<&'self X>);
pub fn main() { let x = 42; let z = Z(A(&x as &X)); let _ = z; }

[klutzy]

It occurs only with tuple structs; as a workaround, you may replace

struct Z<'self>(Enum<&'self X>);

with

struct Z<'self>{
    z: Enum<&'self X>
}

[klutzy]

Sorry. It doesn't solve it generally. I'm now embarrassed that

trait X {}
impl X for int {}
struct Y<'self>{
    x:Option<&'self X>,
}

fn main() {
    let x = 42;
    let a = Some(&x as &X);
    let _y = Y { x: a };
}

works, but

...
fn main() {
    let x = 42;
    let _y = Y { x: Some(&x as &X) }; // inlining a
}

does not.

[cnd]

cc

[alexcrichton]

This has been fixed, flagging as needstest.