Rust-clippy: Hangs forever when building metrics = 0.2.3

[dneuhaeuser-zalando]

$ cargo clippy -V
clippy 0.0.212 (c8e3cfbd 2019-10-28)

Clippy seems to hang forever when "Building" metrics 0.2.3. To reproduce simply create a new project with cargo init add metrics = "0.2.3" to the dependencies in Cargo.toml and run cargo clippy.

This didn't occur before I updated my toolchain with rustup update, which I did today to update to 1.40. I used 1.39 before. Other commands such as cargo check, cargo build (with or without --release) work just fine.

[phansch]

Thanks for the report! I'm able to reproduce this on my end and will try to find a smaller repro case now.

[phansch]

Minimal repro:

/// <foo
struct A {}

Turning the first line into /// <foo> or /// foo doesn't cause the endless build (please don't try it on the playground).

My guess is that it's related to the doc_markdown lint.
Unfortunately I ran out of time for today and will only be able to get back to this tomorrow.

[phansch]

Quick update: This seems to be caused somehow by the cognitive complexity lint. When I disable it in clippy_lints/src/lib.rs, it stops hanging.

[mikerite]

Is this still a problem? I can't reproduce with the minimal repro or the metrics dependency. I'm using clippy master.

[mikerite]

Ok, I get it when I use stable (1.40).

[jpospychala]

This is a bug in pulldown_cmark parser. I can reproduce it in their repo on master with minimal example:

#[test]
fn test_unterminated_foo() {
    use pulldown_cmark::Parser;
    let parser = Parser::new("<foo");
    for _ in parser {}
}