(false positive) doc_markdown should disregard escaped underscores

[lorepozo]

If a docstring has an escaped underscore (\_), then clippy should treat that escaped underscore as any other (insignificant) character.

// lib.rs
//! Suppose a web LaTeX viewer is loaded.
//! (Note that backslashes are escaped for LaTeX.)
//!
//! \\[
//!     \\prod\_{x\\in X} p\_x
//! \\]

results in

warning: you should put `prod_{x\in` between ticks in the documentation
 --> src/lib.rs:5:10
  |
5 | //!     \\prod\_{x\\in X} p\_x
  |          ^^^^^^^^^^
  |
  = note: #[warn(doc_markdown)] on by default
  = help: for further information visit https://rust-lang-nursery.github.io/rust-clippy/v0.0.190/index.html#doc_markdown

warning: you should put `p_x` between ticks in the documentation
 --> src/lib.rs:5:24
  |
5 | //!     \\prod\_{x\\in X} p\_x
  |                        ^^^
  |
  = help: for further information visit https://rust-lang-nursery.github.io/rust-clippy/v0.0.190/index.html#doc_markdown

[lorepozo]

This was on clippy-0.0.190.

[phansch]

It looks like this is caused by us using pulldown_cmark which is turning

\\prod\_{x\\in X} p\_x

into

\prod_{x\in X} p_x

The lint then splits this up into the words \prod_{x\in X} and p_x which are both causing the lint to trigger.
Due to the backslashes being trimmed by pulldown_cmark, there's nothing we can do about that right now, unfortunately.

[hellow554]

This is still an issue today. Any updates on this (after 3 years? :) )