ICE with deep DST coercion

[Kimundi]

Error:

figment_sketch.rs:1:1: 1:1 error: internal compiler error: Encountered errors `[FulfillmentError(Obligation(trait_ref=<_ : core::kinds::Sized>,depth=1),Unimplemented)]` fulfilling `<*mut alloc::rc::RcBox<Component+'static> : core::ptr::RawPtr<alloc::rc::RcBox<Component+'static>>>` during trans
figment_sketch.rs:1 use std::intrinsics::TypeId;
                    ^

Reproduces with:

use std::intrinsics::TypeId;
use std::rc::Rc;

type Fp<T> = Rc<T>;

struct Engine;

trait Component: 'static {}
impl Component for Engine {}

trait Env {
    fn get_component_type_id(&self, type_id: TypeId) -> Option<Fp<Component>>;
}

impl<'a> Env+'a {
    fn get_component<T: Component>(&self) -> Option<Fp<T>> {
        // This line is needed to cause the error:
        let x = self.get_component_type_id(TypeId::of::<T>());
        None
    }
}

trait Figment {
    fn init(&mut self, env: &Env);
}


struct MyFigment;

impl Figment for MyFigment {
    fn init(&mut self, env: &Env) {
        let engine = env.get_component::<Engine>();
    }
}

fn main() {

}

[Kimundi]

cc @nick29581

[Kimundi]

I just now noticed that Rc<T> does not actually yet allow unsized T. Might be related.

[tamird]

This doesn't compile, but it doesn't ICE.

[frewsxcv]

It looks like std::intrinsics::TypeId; no longer exists. Did it get replaced by something else? I imagine there's not much value in adding a regression test with a broken import

[tamird]

from 70f7165:

TypeId is now defined at std::any::TypeId