'rustc' panicked at 'failed to lookup `SourceFile` in new context'

[manio]

Hi.
I did cargo build and suddenly this goes to my console:

error: cannot find attribute `get` in this scope
  --> src/webserver.rs:15:3
   |
15 | #[get("/<name>/<age>")]
   |   ^^^

warning: unused import: `rocket`
 --> src/webserver.rs:4:5
  |
4 | use rocket;
  |     ^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

thread 'rustc' panicked at 'failed to lookup `SourceFile` in new context', src/librustc_middle/ty/query/on_disk_cache.rs:456:17
note: run with `RUST_BACKTRACE=1` environment variable to display 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 1.44.0-nightly (6dee5f112 2020-04-06) running on x86_64-unknown-linux-gnu

note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin

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

error: aborting due to previous error

error: could not compile `hard`.

To learn more, run the command again with --verbose.

I gave it another try and this is the backtrace:
https://pastebin.com/JLQy9Ear

I am using today nightly. It was compiling fine before... anyway as I believe that the problem is with panic - I am reporting this bug.

[jonas-schievink]

Thanks for the report. Can you provide the source code needed to reproduce this?

[manio]

Sure, the exact code which I was trying to build is now here in this branch:
https://github.com/manio/hard/tree/rust-panic

[Bertus-W]

I got the exact same issue at the moment

edit:
cargo clean fixes it for me

[manio]

I also tested 'cargo clean' - and it also worked for me :)
no more this panic...

[jonas-schievink]

Do you remember the change that induced this bug? It looks like this is a problem with incremental compilation, so we'll need to find a change that triggers the issue.

[manio]

@jonas-schievink
I was compiling my project with stable rust version, but today I've started to play with Rocket, so I've added rocket crate and I also did:
rustup override set nightly
Maybe this was the trigger of this problem...

In the mean time I might also did:
rustup target add arm-unknown-linux-gnueabihf - but I am not 100% sure now :(

[jonas-schievink]

@manio I was more wondering about any changes to your code, not the toolchain. It's fine if you don't remember of course, but it would make it easier to track this bug down. Thanks!

[manio]

@jonas-schievink
Oh - that should be trivial as I am trying to commiting often :D
All changes I've done in the code (with switching from stable to nightly) has to be here in this commit:
manio/hard@348cd87
The code has errors if that matters.

[Bertus-W]

For me it happened after this. Also tried rocket, I set ‘rustup default nightly’ and successfully compiled and ran with ‘cargo run’. But I remembered you could override for single projects. So I did ‘rustup default stable’ and then rustup override set nightly. The when i did ‘cargo run’ it gave the error.