error_on_line_overflow does not diagnose function attributes inside macros

[gnzlbg]

macro_rules! foo {
    ($id:ident) => {
        macro_rules! bar {
            ($id2:tt) => {
                #[cfg(any(target_feature = $id2, target_feature = $id2, target_feature = $id2, target_feature = $id2, target_feature = $id2))]
                fn $id() {}
            };
        }
    };
}

fn main() {}

rustfmt, as expected, does not format this code (its inside a macro), but with error_on_line_overflow = true in the rustfmt.toml I'd expect cargo fmt -- --check to diagnose that the line where the #[cfg(...)] macro is located is too long, yet no diagnostic is emitted.

[topecongiro]

I could not reproduce this locally with rustfmt 0.99.6-nightly (750b2526 2018-10-18). Would you tell us the repository you were working on and the version of rustfmt you used?

[gnzlbg]

@topecongiro packed_simd master using the preview, there are many lines (hundreds) starting with #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] that go over the line limit, but I couldn't get rustfmt to error on those.

[topecongiro]

@gnzlbg Thank you!

When error_on_line_overflow is set to true, rustfmt reports any line that exceeds max width except comment and string literal. Looks like the logic is too pessimistic, and the string literals in #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] ("wasm32") is preventing the error report.

[gnzlbg]

Ah damn, trying to find a MWE, the one I came up with does not use any string literals =/

[gnzlbg]

@topecongiro so it appears that error_on_line_overflow also fails in many more cases.

packed_simd contains a script in ci/max_line_width.sh that checks the max line width for all .rs files and fails on a line if the line does not contain http (links cannot be split across line). It appears that all matches found by this script are errors, which finds many (the script currently fails on the first match, but you might want to disable that).