Running cargo clippy then making changes seems to hide all lints; requires removing target/debug/build

[sollyucko]

Running cargo clippy then making changes seems to hide all lints; requires removing target/debug/build.

How to trigger the problem

1. Create a Cargo project.
2. Add some code that triggers a Clippy lint.
3. Run cargo clippy. Make sure this outputs lint messages.
4. Modify the code, without resolving (all of) the issues. (Even just re-saving the file might work.)
5. Run cargo clippy.
6. Modify the code, without resolving (all of) the issues. (Even just re-saving the file might work.)
7. Run cargo clippy. Problem: no lint messages are displayed.
8. Run rm -r target/debug/build and/or rm -r target/debug/build (make sure to delete a folder with files in it).
9. Run cargo clippy. Workaround: the messages are visible again.

Version info

clippy 0.0.212 (23549a8 2020-03-16)
cargo 1.44.0-nightly (7019b3ed3 2020-03-17)
rustc 1.44.0-nightly (f509b26a7 2020-03-18)
Linux ghostwheel 4.19.0-8-amd64 #1 SMP Debian 4.19.98-1 (2020-01-26) x86_64 GNU/Linux

[phansch]

Hi, thanks for the report! This is a known issue and will eventually be fixed by #3837. You can also run touch src/main.rs to display the lint messages again.

[vn971]

@phansch hi, thanks for the explanation and the work-around suggestion! One week after your comment here though, the referenced issue got an update:

We have decided to not move cargo-clippy into Cargo, but instead provide better integration points so that it is not necessary.
...

With that in mind, should this issue be re-opened? What's the path to solve it?

[flip1995]

This issue is still tracked in #3837 and we're currently waiting for cargo to stabilize some internals to get the fix to stable. In the meantime you can use cargo clippy -Zunstable-options on nightly, where this should be fixed.

[vn971]

@flip1995 Thanks for explaining!