Missed coverage when function is inlined

[Nilstrieb]

When a function is inlined, it's sometimes marked as not executed.

To Reproduce

fn lol() {}

pub fn uwu() {
    lol();
}

#[test]
fn wow() {
    uwu();
}

compiled using RUSTFLAGS='-Cpasses=inline' cargo tarpaulin

|| Uncovered Lines:
|| src/lib.rs: 3, 6
|| Tested/Total Lines:
|| src/lib.rs: 0/2 +0.00%
||
0.00% coverage, 0/2 lines covered, +0.00% change in coverage

Expected behavior
I expect both lines in the functions to be covered, since they are tested.

I strongly think that this is a cargo-tarpaulin bug as the generated LLVM IR seems to contain the coverage statements correctly and cargo-llvm-cov also shows the entire file as covered.

[ewoolsey]

Bump on this as well! Also having this problem. @Nilstrieb did you find a solution?

[Nilstrieb]

no, I was just playing around so I didn't need one

[Sajjon]

I have this problem, preventing me from getting my well deserved 95% code coverage (reported ca 81%) 😬

[Pier4413]

I just bumped into this problem too

logger::warn!(
                    "Error while processing message due to {}",
                    error.to_string()
                );

The report is somewhat very disturbing because the line

error.to_string()

is reported as covered but not

logger::warn!(

but if I inline the code like this:

logger::warn!("Error while processing message due to {}", error.to_string());

It works wonderfully. I wonder if any of you have a solution to avoid that? Because the first version is what cargo fmt produces, so it will be a little heavy to reformat everything after the default formatter

For information:

$ rustc --version
rustc 1.76.0 (07dca489a 2024-02-04)

$ cargo --version
cargo 1.76.0 (c84b36747 2024-01-18)

$ cargo tarpaulin --version
cargo-tarpaulin-tarpaulin 0.28.0