Rustfmt does not format some redundant imports

[jyn514]

Describe the bug

Rustfmt does not normalize use std::rc::Weak as Weak; to use std::rc::Weak; in some cases.

To Reproduce

x.py fmt on https://github.com/rust-lang/rust/blob/c3ed6681ff8d446e68ce272be4bf66f4145f6e29/compiler/rustc_data_structures/src/sync.rs#L224

Expected behavior

It should turn that line into use std::rc::Weak;, the same way it does on playground: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=2fbcb920f10e1ad6b4883e3970eba5cc. I'm not sure why this only breaks on rustc.

Meta

• rustfmt version: rustfmt: nightly-2020-11-19
• From where did you install rustfmt?: however x.py downloads it, probably CI artifacts directly?
• How do you run rustfmt: x.py fmt

[jyn514]

This might be because it's inside a cfg_if!?

[jyn514]

Ok yes, this was because of the macro: https://play.rust-lang.org/?version=beta&mode=debug&edition=2018&gist=b39c431c5fba50549d424848e86a009d

[calebcartwright]

Ok yes, this was because of the macro:

Correct. Mac call formatting is intentionally pretty limited for various reasons (complexity, failure to be semantics preserving, high potential for butchering, etc.) and that definitely holds true for items within cfg_if. rustfmt will recurse into and format any mods defined or imported within cfg_if, but not the items themselves

[calebcartwright]

Going to go ahead and close as there's various other open issues like #8 around macro and mac call formatting