#[path = "."] fails with: Error writing files: io error: Failed to find module bar in "." None

[Veetaha]

Describe the bug

Both of the following definitions confuse rustfmt

#[path = "."] 
mod foo { ... }
#[path = ""] 
mod foo { ... }

cargo fmt reports respectively:

Error writing files: io error: Failed to find module bar in "." None

Error writing files: io error: Failed to find module bar in "" None

However cargo build works just fine.

To Reproduce

Follow the instructions in README.md here: https://github.com./Veetaha/rustfmt-bugreport

Expected behavior

Rustfmt should finish without an error formatting all files, including those referenced via #[path = "foo.bar.rs"] attribute.

Meta

• rustfmt version: rustfmt 1.4.16-stable (939e164 2020-06-11)
• From where did you install rustfmt?: rustup
• How do you run rustfmt: cargo fmt

I use this code to generate a nested module structure for files generated in a flat directory. It works when compiling but
formatting these files with cargo fmt currently doesn't work. If you know any workarounds I will appreciate!

[ayazhafiz]

This was fixed in #4194, but hasn't been released yet (only as a part of https://github.com./rust-lang/rustfmt/releases/tag/v2.0.0-rc.2)

[calebcartwright]

Thanks for the report @Veetaha and confirmation @ayazhafiz. Closing