RA is bad at completing rustdoc lints

[jyn514]

This is a couple different bug reports in one; let me know if you'd prefer I open more issues.

1. Typing rustdoc:: resets the suggestions: https://drive.google.com/file/d/1lY7dDREBvyozmK0tSxYAFuO0ask7btfD/view?usp=sharing (this might just be #![allow(clippy:: incorrectly completes with a leading clippy:: #7144).
2. Not all rustdoc lints seem to be supported? https://drive.google.com/file/d/1iXFox4VAckasntgoqti6Vzoh5Ndxgsu9/view?usp=sharing

For 2, I think rather than hard-coding the list of lints, RA should discover it from rustdoc itself with -W help (should hopefully be implemented on the next nightly: rust-lang/rust#83895. Then it will always be up to date and won't have to worry about renamed lints and that sort of thing.

[jyn514]

Unfortunately -Whelp doesn't seem to support JSON output :/ if that would be helpful to you I think it would be reasonable to add, I can make an MCP. Let me know.

The current output looks like this:

Available lint options:
    -W <foo>           Warn about <foo>
    -A <foo>           Allow <foo>
    -D <foo>           Deny <foo>
    -F <foo>           Forbid <foo> (deny <foo> and all attempts to override)


Lint checks provided by rustc:

                                                       name  default  meaning
                                                       ----  -------  -------
                     absolute-paths-not-starting-with-crate  allow    fully qualified paths that start with a module name instead of `crate`, `self`, or an extern crate name
                                       anonymous-parameters  allow    detects anonymous parameters
                                               box-pointers  allow    use of owned (Box type) heap memory
...
Lint groups provided by rustc:

                       name  sub-lints
                       ----  ---------
                   warnings  all lints that are set to issue warnings
        future-incompatible  keyword-idents, anonymous-parameters, forbidden-lint-groups, illegal-floating-point-literal-pattern, private-in-public, pub-use-of-private-extern-crate, invalid-type-param-default, const-err, unaligned-references, patterns-in-fns-without-body, missing-fragment-specifier, late-bound-lifetime-arguments, order-dependent-trait-objects, coherence-leak-check, tyvar-behind-raw-pointer, absolute-paths-not-starting-with-crate, unstable-name-collisions, where-clauses-object-safety, proc-macro-derive-resolution-fallback, macro-expanded-macro-exports-accessed-by-absolute-paths, ill-formed-attribute-input, conflicting-repr-hints, ambiguous-associated-items, mutable-borrow-reservation-conflict, indirect-structural-match, pointer-structural-match, nontrivial-structural-match, soft-unstable, cenum-impl-drop-cast, const-evaluatable-unchecked, uninhabited-static, unsupported-naked-functions, semicolon-in-expressions-from-macros, legacy-derive-helpers, proc-macro-back-compat, array-into-iter

Lint tools like Clippy can provide additional lints and lint groups.

[jyn514]

should hopefully be implemented on the next nightly: rust-lang/rust#83895

This has landed :)

[Veykril]

Just tried rustdoc -W help to see its output but it does not work for me as it just gives me error: missing file operand.

[Veykril]

Oh passing it a random file does make it work, that seems odd given rustc works without an input file for this.

Also is this supposed to also emit rustc lints? Would've expected to only see rustdoc lints by doing this.

[jyn514]

Just tried rustdoc -W help to see its output but it does not work for me as it just gives me error: missing file operand.

rust-lang/rust#88831

[Veykril]

Fixed in #10594