the compiler unexpectedly panicked. this is a bug.

[sagiegurari]

I upgraded to a new rust nightly and now it seems the compiler crashes during build.

• I'm using raspberry pi 3

> uname -a
Linux pidesk 4.9.41-v7+ #1023 SMP Tue Aug 8 16:00:15 BST 2017 armv7l GNU/Linux

• rust version:

> rustc --version
rustc 1.26.0-nightly (55c984ee5 2018-03-16)

• code example which causes issue: https://github.com/sagiegurari/misc-test/tree/rust2
• error:

> cargo check
Compiling test v0.0.1 (file:///media/projects/misc-test)
Finished dev [unoptimized + debuginfo] target(s) in 0.70 secs

> cargo build --verbose                                                                                                                                                     
   Compiling utf8-ranges v1.0.0
     Running `rustc --crate-name utf8_ranges /home/pi/.cargo/registry/src/github.com-1ecc6299db9ec823/utf8-ranges-1.0.0/src/lib.rs --crate-type lib --emit=dep-info,link -C debuginfo=2 -C metadata=0d901130be5be452 -C extra-filename=-0d901130be5be452 --out-dir /media/projects/misc-test/target/debug/deps -L dependency=/media/projects/misc-test/target/debug/deps --cap-lints allow`
thread 'rustc' panicked at 'index out of bounds: the len is 21696714 but the index is 21696714', /checkout/src/libserialize/opaque.rs:259:21
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 1.26.0-nightly (55c984ee5 2018-03-16) running on armv7-unknown-linux-gnueabihf

note: compiler flags: -C debuginfo=2 --crate-type lib

note: some of the compiler flags provided by cargo are hidden

error: Could not compile `utf8-ranges`.

Caused by:
  process didn't exit successfully: `rustc --crate-name utf8_ranges /home/pi/.cargo/registry/src/github.com-1ecc6299db9ec823/utf8-ranges-1.0.0/src/lib.rs --crate-type lib --emit=dep-info,link -C debuginfo=2 -C metadata=0d901130be5be452 -C extra-filename=-0d901130be5be452 --out-dir /media/projects/misc-test/target/debug/deps -L dependency=/media/projects/misc-test/target/debug/deps --cap-lints allow` (exit code: 101)

[bjorn3]

Looks like dup of #49065

[sagiegurari]

ya maybe. tried to find something similar, but didn't find in the titles.

[sagiegurari]

I guess #48923 is related as well as #49065 was just closed

[sagiegurari]

Actually reading more, I see they complain on incremental builds and for me it is a simple clean build.
Might be wrong but it does look like high priority.

[bjorn3]

Cargo uses incremental builds by default now (rust-lang/cargo#4817)

[nikomatsakis]

Hopefully a duplicate of #48923.

@sagiegurari can you verify if (a) using CARGO_INCREMENTAL=0 stops the problem and (b) get the output using RUST_BACKTRACE=1?

[nikomatsakis]

triage: P-high

Since likely incremental bug, assigning to @michaelwoerister

[sagiegurari]

I upgraded to the latest nightly 2018-03-20 and it looks like everything is working fine now.
Wasn't aware there was a fix already.

[michaelwoerister]

This was probably MIRI related then. Thanks for the update, @sagiegurari!