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ICE with HRTB: Broken MIR in DefId [...] could not prove Binder #59311

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@cbourjau

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@cbourjau

rustc ICEes when trying to compile the following code. As far as I can tell, the issue is due to the HRTB. All other issues I found mentioning broken MIR in DefId where either using unstable features and/or related to impl Trait which seems to be unrelated to this issue.

Playground link

use std::sync::mpsc::channel;

pub struct S<T> {
    pub thing: T,
}

#[derive(Debug)]
struct E;

impl std::fmt::Display for E {
    fn fmt(&self, _f: &mut std::fmt::Formatter) -> std::fmt::Result {
        unimplemented!()
    }
}

impl std::error::Error for E {}

impl<T> S<T> {
    pub fn do_thing()
    where
        for<'a> &'a T: 'static,
    {
        let (_sender, rx) = channel::<T>();
        let _ = rx.recv().map_err(|_| E);
    }
}

Meta

On the playground, I am able to reproduce the ICE on stable (1.33), beta, and nightly. Locally I have the following setup:

rustc --version --verbose:

rustc 1.33.0 (2aa4c46cf 2019-02-28)
binary: rustc
commit-hash: 2aa4c46cfdd726e97360c2734835aa3515e8c858
commit-date: 2019-02-28
host: x86_64-unknown-linux-gnu
release: 1.33.0
LLVM version: 8.0

Backtrace:

error: internal compiler error: broken MIR in DefId(0/0:9 ~ playground[59ee]::{{impl}}[2]::do_thing[0]) (NoSolution): could not prove Binder(OutlivesPredicate(&'a T, ReStatic))
  --> src/lib.rs:24:35
   |
24 |         let _ = rx.recv().map_err(|_| E);
   |                                   ^^^^^

thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', src/librustc_errors/lib.rs:322:17
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
   1: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:70
   2: std::panicking::default_hook::{{closure}}
             at src/libstd/sys_common/backtrace.rs:58
             at src/libstd/panicking.rs:200
   3: std::panicking::default_hook
             at src/libstd/panicking.rs:215
   4: rustc::util::common::panic_hook
   5: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:482
   6: std::panicking::begin_panic
   7: <rustc_errors::Handler as core::ops::drop::Drop>::drop
   8: core::ptr::real_drop_in_place
   9: core::ptr::real_drop_in_place
  10: core::ptr::real_drop_in_place
  11: <scoped_tls::ScopedKey<T>>::set

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    A-MIRArea: Mid-level IR (MIR) - https://blog.rust-lang.org/2016/04/19/MIR.htmlC-bugCategory: This is a bug.E-needs-testCall for participation: An issue has been fixed and does not reproduce, but no test has been added.I-ICEIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.glacierICE tracked in rust-lang/glacier.

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