tarpaulin: bug: tests fail when running cargo tarpaulin with recent nightly toolchain

Describe the bug We have been using tarpaulin for our project for quite some time.

We haven’t had any issues until now. We updated toolchain to more recent one -> nightly-2021-11-08.

And using tarpaulin to generate code coverage, our tests started failing. The tests produce different results than expected.

However, running just the tests without tarpaulin is fine and results are correct.

Note using any earlier toolchain than the one from 2021-11-08 is fine (eg. 2021-11-07 is fine ).

To Reproduce our project is quite complex, using even more complex Substrate framework.

However to reproduce - it is fairly simple:

1. Clone repository Basilisk-node
2. There is rust-toolchain file - edit to change toolchain to one from 2021-11-08.
3. Run make coverage ( takes quite some time ). Fails.
4. Run make test. Tests pass.

Expected behavior I’d expect tests not to fail considering they pass correctly without tarpaulin.

Personally, I cannot tell yet what can cause this issue.

I’ll dig deeper to figure out what have the failing tests in common - it is not obvious from the first quick look.

but I figured it would be good to let you know, as there might be something which you are already aware of.

Version cargo tarpaulin --version cargo-tarpauin version: 0.18.5