ICE: Implementing trait with associated constant and &Self bound

[madsmtm]

Code

pub trait First {
    const CONST: bool;
}
pub trait Second {}

impl<'a> First for dyn Second where &'a Self: First {
    const CONST: bool = <&Self>::CONST;
}

Playground link.

Meta

Tested on rust 1.54.0 and nightly 2021-08-31.

rustc --version --verbose:

rustc 1.54.0 (a178d0322 2021-07-26)
binary: rustc
commit-hash: a178d0322ce20e33eac124758e837cbd80a6f633
commit-date: 2021-07-26
host: x86_64-apple-darwin
release: 1.54.0
LLVM version: 12.0.1

Error output

error: internal compiler error: Encountered error `Unimplemented` selecting `Binder(<&dyn Second as First>, [])` during codegen
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/codegen.rs:68:32

error: internal compiler error: ty::ConstKind::Error constructed but no error reported.
  |
  = note: delayed at compiler/rustc_middle/src/ty/consts.rs:183:43

thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', compiler/rustc_errors/src/lib.rs:1166:13

Backtrace

stack backtrace:
   0: rust_begin_unwind
             at library/std/src/panicking.rs:515:5
   1: std::panicking::begin_panic_fmt
             at library/std/src/panicking.rs:457:5
   2: rustc_errors::HandlerInner::flush_delayed
   3: <rustc_errors::HandlerInner as core::ops::drop::Drop>::drop
   4: core::ptr::drop_in_place<rustc_session::parse::ParseSess>
   5: <alloc::rc::Rc<T> as core::ops::drop::Drop>::drop
   6: core::ptr::drop_in_place<rustc_interface::interface::Compiler>
   7: rustc_span::with_source_map
   8: rustc_interface::interface::create_compiler_and_run
   9: scoped_tls::ScopedKey<T>::set

[SNCPlay42]

This version without dyn Trait also ICEs (playground):

pub trait Foo {
    const CONST: bool;
}

impl <'a> Foo for () where &'a Self: Foo {
    const CONST: bool = <&Self>::CONST;
}

[SNCPlay42]

Both versions compile on Rust 1.43.0: godbolt

@rustbot label regression-from-stable-to-stable

[apiraino]

probably too old to bisect but it seems introduced in rollup #70371 on nightly-2020-03-26

[apiraino]

Assigning priority as discussed in the Zulip thread of the Prioritization Working Group.

@rustbot label -I-prioritize +P-medium