Path canonicalization warnings and errors when running cargo commands in a RAM disk on Windows

[MoodyMoon]

How to reproduce:

1. Install ImDisk Virtual Disk Driver from http://www.ltr-data.se/opencode.html/
2. Create a disk backed by physical memory.
3. Change the working directory to its root.
4. Run cargo.exe new test1

Sample output:

warning: could not canonicalize path: 'Z:\'
warning: could not canonicalize path: 'Z:\'
     Created binary (application) `test1` package

5. Change the working directory to test1
6. Run cargo.exe run

Sample output:

warning: could not canonicalize path: 'Z:\test1'
warning: could not canonicalize path: 'Z:\test1'
warning: could not canonicalize path: 'Z:\'
   Compiling test1 v0.1.0 (Z:\test1)
error: incremental compilation: error canonicalizing path `Z:\test1\target\debug\incremental\test1-17ruhvudqlj17`: Incorrect function. (os error 1)

thread 'rustc' panicked at 'trying to get session directory from `IncrCompSession`: NotInitialized', src\librustc_session\session.rs:690:48
stack backtrace:
   0: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
   1: core::fmt::write
   2: <std::io::IoSliceMut as core::fmt::Debug>::fmt
   3: std::panicking::take_hook
   4: std::panicking::take_hook
   5: rustc_driver::report_ice
   6: std::panicking::rust_panic_with_hook
   7: rust_begin_unwind
   8: std::panicking::begin_panic_fmt
   9: rustc_session::session::Session::incr_comp_session_dir
  10: rustc_incremental::persist::fs::garbage_collect_session_directories
  11: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::compile
  12: rustc_interface::passes::BoxedResolver::to_resolver_outputs
  13: rustc_interface::queries::Queries::register_plugins
  14: rustc_driver::pretty::print_after_hir_lowering
  15: <rustc_middle::ty::instance::InstanceDef as rustc_middle::ty::query::keys::Key>::query_crate
  16: <rustc_middle::ty::instance::InstanceDef as rustc_middle::ty::query::keys::Key>::query_crate
  17: rustc_errors::snippet::MultilineAnnotation::increase_depth
  18: rustc_driver::pretty::print_after_hir_lowering
  19: std::sys::windows::thread::Thread::new
  20: BaseThreadInitThunk
  21: RtlUserThreadStart
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/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.44.1 (c7087fe00 2020-06-17) running on x86_64-pc-windows-msvc

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

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

query stack during panic:
end of query stack
error: aborting due to previous error

error: could not compile `test1`.

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

[retep998]

Just another case of #59117 being unsolved still.

[insomnimus]

I have the same exact issue.

[ArtifyCZ]

I have the same problem.
But CLion let me create a project and load it, ..., just not compile it.

[Enselic]

Triage: This is about problems canonicalizing paths on RAM drives. So is #48249, so closing as duplicate.