cargo check - make possible to use "pipes" instead of files

[Dushistov]

As I understand cargo check works only with files,
so work pattern should looks like:

1. Enter a couple of symbols
2. Save file to disk
3. Run cargo check

A lot of saves, bad for SSD.

So it would be good if cargo check provide interface like:

cargo check --temp-file-name src/lib.rs

in such mode cargo read content of modified src/lib.rs from stdin,
and do cargo check as src/lib.rs contains data that cargo read from stdin.

This helps for example flycheck-rust: flycheck/flycheck-rust#29

[epage]

For me, the big challenge is that IDEs would likely have multiple files open for edit that need to be checked and stdin wouldn't be sufficient. https://internals.rust-lang.org/t/jar-for-rust-single-file-crate-support-for-rustc/19576 does do some exploring for alternative ways for Cargo to communicate source buffers to rustc.