Rustdoc ignores -W help

[jyn514]

I tried this code: rustdoc -W help
I expected to see this happen: Rustdoc prints a list of all lints, the same way rustc does.
Instead, this happened: Rustdoc ignored the flag.

Meta

rustdoc --version: rustdoc 1.53.0-nightly (0b417ab 2021-04-03)

[eggyal]

-W help option is parsed into librustdoc::config::Options::describe_lints, but is then ignored:

rust/src/librustdoc/config.rs

Lines 100 to 102 in 39eee17

	/// Whether to ask rustc to describe the lints it knows. Practically speaking, this will not be
	/// used, since we abort if we have no input file, but it's included for completeness.
	crate describe_lints: bool,

It should be pretty straightforward to instead call rustc_driver::describe_lints when this flag is set.

@rustbot claim

[jyn514]

Make sure you call init_lints first, or it will be missing rustdoc's own lints.

[eggyal]

Re adding a test for this... is there any way to have compiletest check only for whether some substring appears within stderr? Else every time a lint is added/removed, or its level modified, the test will need updating—which seems far too brittle to me?

[jyn514]

Else every time a lint is added/removed, or its level modified, the test will need updating—which seems far too brittle to me?

I mean, personally that seems ok to me as long as you can update it with --bless. But if you think it's a hassle you could use --error-pattern.