compiler error on cargo test

[gilesbradshaw]

It says you'd appreciate report ...

I am 99% sure this code was compiling - but now

Code

use std::fs;
use std::error::Error;

pub fn run(config: Config) -> Result<(), Box<dyn Error>>{
   
  let contents = fs::read_to_string(config.filename)?;
  
  println!("With text:\n{}", contents);
  Ok(())
}

pub struct Config {
  pub query: String,
  pub filename: String
}

impl Config {
  pub fn new(args: &[String]) -> Result<Config, &'static str> {
      if args.len() < 3 {
          return Err("u need s args");
      }
      let query = args[1].clone();
      let filename = args[2].clone();
      Ok(
          Config {
              query,
              filename,
          }
      )
  }   
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_config() {
      if let Ok(config) = Config::new(&[String::from(""), String::from("search"), String::from("file"),]) {
        assert_eq!(config.query, "search", "its search");
        
      }
    }
}

Meta

rustc --version --verbose:

rustc 1.50.0-nightly (1700ca07c 2020-12-08)
binary: rustc
commit-hash: 1700ca07c6dd7becff85678409a5df6ad4cf4f47
commit-date: 2020-12-08
host: x86_64-unknown-linux-gnu
release: 1.50.0-nightly

Error output

$ RUST_BACKTRACE=1 cargo test
   Compiling minigrep v0.1.0 (/home/giles/rust/minigrep)
thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', compiler/rustc_middle/src/ty/query/mod.rs:235:5
stack backtrace:
   0: rust_begin_unwind
             at /rustc/1700ca07c6dd7becff85678409a5df6ad4cf4f47/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/1700ca07c6dd7becff85678409a5df6ad4cf4f47/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/1700ca07c6dd7becff85678409a5df6ad4cf4f47/library/core/src/panicking.rs:50:5
   3: rustc_middle::ty::query::try_load_from_on_disk_cache
   4: rustc_query_system::dep_graph::graph::DepGraph<K>::exec_cache_promotions
   5: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
   6: rustc_incremental::persist::save::save_in
   7: rustc_data_structures::sync::join
   8: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
   9: rustc_incremental::persist::save::save_dep_graph
  10: rustc_codegen_ssa::base::finalize_tcx
  11: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate
  12: rustc_session::utils::<impl rustc_session::session::Session>::time
  13: rustc_interface::passes::QueryContext::enter
  14: rustc_interface::queries::Queries::ongoing_codegen
  15: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  16: rustc_span::with_source_map
  17: rustc_interface::interface::create_compiler_and_run
  18: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose 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/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.50.0-nightly (1700ca07c 2020-12-08) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental

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

query stack during panic:
end of query stack
error: could not compile `minigrep`

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

Backtrace

<backtrace>

[camelid]

Appears to be a duplicate of #79661. Can you please try with the latest nightly and let me know if it works? If it does not, you may need to wait for the one after that.

[gilesbradshaw]

actually I have "fixed" it by deleting target directory - now it compiles fine..
If I get it again i will also try and fix by updating and report back ..

[camelid]

Yes, this is an incremental compilation bug, which means that deleting the target directory will at least temporarily fix the problem. Updating your version should actually fix it though.

[gilesbradshaw]

yeap it happened again - fixed with upgrade