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ICE from const item in lifetime-parametric impl #56445
Description
Reduced test case (play) from comment below:
struct OnDiskDirEntry<'a> { _s: &'a usize }
impl<'a> OnDiskDirEntry<'a> {
const LFN_FRAGMENT_LEN: usize = 2;
fn lfn_contents(&self) -> [char; Self::LFN_FRAGMENT_LEN] { loop { } }
}Another repro case: #56445 (comment)
Original bug report follows
If I run cargo test on https://github.com/thejpster/embedded-sdmmc-rs/tree/generates_ice, I get an ICE:
user@host:~/Documents/programming/embedded-sdmmc$ cargo test
Compiling embedded-sdmmc v0.1.0 (/home/jonathan/Documents/programming/embedded-sdmmc)
thread 'main' panicked at 'assertion failed: `(left == right)`
left: `Some(NodeId(1093))`,
right: `None`: free_scope: DefId(0/0:72 ~ embedded_sdmmc[4f8a]::fat[0]::{{impl}}[4]) not recognized by the region scope tree for None / Some(DefId(0/0:79 ~ embedded_sdmmc[4f8a]::fat[0]::{{impl}}[4]::lfn_contents[0]))', librustc/middle/region.rs:673:13
note: Run with `RUST_BACKTRACE=1` for a backtrace.
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.31.0-beta.19 (42053f9f0 2018-11-26) running on x86_64-unknown-linux-gnu
note: compiler flags: -C debuginfo=2 -C incremental --crate-type lib
note: some of the compiler flags provided by cargo are hidden
error: Could not compile `embedded-sdmmc`.
warning: build failed, waiting for other jobs to finish...
thread 'main' panicked at 'assertion failed: `(left == right)`
left: `Some(NodeId(1090))`,
right: `None`: free_scope: DefId(0/0:71 ~ embedded_sdmmc[be94]::fat[0]::{{impl}}[4]) not recognized by the region scope tree for None / Some(DefId(0/0:78 ~ embedded_sdmmc[be94]::fat[0]::{{impl}}[4]::lfn_contents[0]))', librustc/middle/region.rs:673:13
note: Run with `RUST_BACKTRACE=1` for a backtrace.
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.31.0-beta.19 (42053f9f0 2018-11-26) running on x86_64-unknown-linux-gnu
note: compiler flags: -C debuginfo=2 -C incremental
note: some of the compiler flags provided by cargo are hidden
error: Could not compile `embedded-sdmmc`.
To learn more, run the command again with --verbose.
user@host:~/Documents/programming/embedded-sdmmc$ cargo +nightly test
Compiling embedded-sdmmc v0.1.0 (/home/jonathan/Documents/programming/embedded-sdmmc)
thread 'main' panicked at 'assertion failed: `(left == right)`
left: `Some(NodeId(1093))`,
right: `None`: free_scope: DefId(0/0:72 ~ embedded_sdmmc[46a7]::fat[0]::{{impl}}[4]) not recognized by the region scope tree for None / Some(DefId(0/0:79 ~ embedded_sdmmc[46a7]::fat[0]::{{impl}}[4]::lfn_contents[0]))', src/librustc/middle/region.rs:673:13
note: Run with `RUST_BACKTRACE=1` for a backtrace.
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.32.0-nightly (400c2bc5e 2018-11-27) running on x86_64-unknown-linux-gnu
note: compiler flags: -C debuginfo=2 -C incremental --crate-type lib
note: some of the compiler flags provided by cargo are hidden
error: Could not compile `embedded-sdmmc`.
warning: build failed, waiting for other jobs to finish...
thread 'main' panicked at 'assertion failed: `(left == right)`
left: `Some(NodeId(1090))`,
right: `None`: free_scope: DefId(0/0:71 ~ embedded_sdmmc[93d1]::fat[0]::{{impl}}[4]) not recognized by the region scope tree for None / Some(DefId(0/0:78 ~ embedded_sdmmc[93d1]::fat[0]::{{impl}}[4]::lfn_contents[0]))', src/librustc/middle/region.rs:673:13
note: Run with `RUST_BACKTRACE=1` for a backtrace.
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.32.0-nightly (400c2bc5e 2018-11-27) running on x86_64-unknown-linux-gnu
note: compiler flags: -C debuginfo=2 -C incremental
note: some of the compiler flags provided by cargo are hidden
error: Could not compile `embedded-sdmmc`.
To learn more, run the command again with --verbose.
user@host:~/Documents/programming/embedded-sdmmc$ cargo version
cargo 1.31.0-beta (339d9f9c8 2018-11-16)
user@host:~/Documents/programming/embedded-sdmmc$ cargo +nightly version
cargo 1.32.0-nightly (b3d0b2e54 2018-11-15)
I'm using 2018 edition syntax, so I can only test on beta and nightly.
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Area: const generics (parameters and arguments)Area: Lazy normalization (tracking issue: #60471)Area: Lifetimes / regionsCategory: This is a bug.Diagnostics: Confusing error or lint that should be reworked.Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue.Call for participation: An issue has been fixed and does not reproduce, but no test has been added.`#![feature(const_generics)]`Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️Relevant to the compiler team, which will review and decide on the PR/issue.Enabling feature `const_generics` fixes the issue.ICE tracked in rust-lang/glacier.
Activity
thejpster commentedon Dec 5, 2018
Commenting out the
lfn_contents()function in fat.rs makes the ICE go away.The ICE occurs on a
cargo buildas well as acargo test.thejpster commentedon Dec 5, 2018
Replacing both instances of Self::FRAGMENT_LEN in the
lfn_contents()function with the literal integer 13 makes the ICE go away.jonas-schievink commentedon Jun 9, 2019
Still reproduces on 1.35.0 and nightly (
rustc 1.37.0-nightly (991c719a1 2019-06-08)).Click for backtrace
Backtrace:
pnkfelix commentedon Jun 13, 2019
triage: P-high, removing nomination, assigning to self for initial investigation.
pnkfelix commentedon Jun 14, 2019
Note: While I replicate the ICE as described on beta, I see a different ICE on nightly on this branch, namely:
For reference (in case it matters e.g. for a hypothetical backport) was injected between +nightly-2019-05-25 and +nightly-2019-05-26. Further bisection thanks to rustup-toolchain-install-master "pinpointed" the change to this rollup PR:
I'm pretty sure the change in behavior is due to PR #61118.
Click for stack trace
pnkfelix commentedon Jun 14, 2019
Okay here is reduced test case (play):
pnkfelix commentedon Jun 14, 2019
@thejpster another workaround, by the way, is to move the
const LFN_FRAGMENT_LENout of theimpl(and then change the use to sayLFN_FRAGMENT_LENinstead ofSelf::LFN_FRAGMENT_LEN)pnkfelix commentedon Jun 17, 2019
And yet another workaround is to say
[char; OnDiskDirEntry::LFN_FRAGMENT_LEN]instead of[char; Self::LFN_FRAGMENT_LEN]in the return type.24 remaining items
Auto merge of rust-lang#79135 - lcnr:the-paleogenesis-of-generic-germ…
JohnTitor commentedon Dec 30, 2020
Triage:
The reduced snippet (#56445 (comment)) and #56445 (comment) are no longer ICE with the latest nightly: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=2d74015d14721b961d717ac11c343a0c
sjakobi commentedon Mar 27, 2021
@rustbot claim
Add regression tests for rust-lang#56445
Rollup merge of rust-lang#83569 - sjakobi:issue56445-regression-test,…
Auto merge of rust-lang#83573 - JohnTitor:rollup-28jnzsr, r=JohnTitor