clippy: Let rustc handle describing lints

Author: flip1995

src/tools/clippy/src/driver.rs

@@ -8,7 +8,6 @@
 
 // FIXME: switch to something more ergonomic here, once available.
 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
-extern crate rustc_data_structures;
 extern crate rustc_driver;
 extern crate rustc_errors;
 extern crate rustc_interface;
@@ -26,8 +25,6 @@ use std::panic;
 use std::path::{Path, PathBuf};
 use std::process::{exit, Command};
 
-mod lintlist;
-
 /// If a command-line option matches `find_arg`, then apply the predicate `pred` on its value. If
 /// true, then return it. The parameter is assumed to be either `--arg=value` or `--arg value`.
 fn arg_value<'a, T: Deref<Target = str>>(
@@ -92,113 +89,6 @@ impl rustc_driver::Callbacks for ClippyCallbacks {
     }
 }
 
-#[allow(clippy::find_map, clippy::filter_map)]
-fn describe_lints() {
-    use lintlist::{Level, Lint, ALL_LINTS, LINT_LEVELS};
-    use rustc_data_structures::fx::FxHashSet;
-
-    println!(
-        "
-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)
-
-"
-    );
-
-    let lint_level = |lint: &Lint| {
-        LINT_LEVELS
-            .iter()
-            .find(|level_mapping| level_mapping.0 == lint.group)
-            .map(|(_, level)| match level {
-                Level::Allow => "allow",
-                Level::Warn => "warn",
-                Level::Deny => "deny",
-            })
-            .unwrap()
-    };
-
-    let mut lints: Vec<_> = ALL_LINTS.iter().collect();
-    // The sort doesn't case-fold but it's doubtful we care.
-    lints.sort_by_cached_key(|x: &&Lint| (lint_level(x), x.name));
-
-    let max_lint_name_len = lints
-        .iter()
-        .map(|lint| lint.name.len())
-        .map(|len| len + "clippy::".len())
-        .max()
-        .unwrap_or(0);
-
-    let padded = |x: &str| {
-        let mut s = " ".repeat(max_lint_name_len - x.chars().count());
-        s.push_str(x);
-        s
-    };
-
-    let scoped = |x: &str| format!("clippy::{}", x);
-
-    let lint_groups: FxHashSet<_> = lints.iter().map(|lint| lint.group).collect();
-
-    println!("Lint checks provided by clippy:\n");
-    println!("    {}  {:7.7}  meaning", padded("name"), "default");
-    println!("    {}  {:7.7}  -------", padded("----"), "-------");
-
-    let print_lints = |lints: &[&Lint]| {
-        for lint in lints {
-            let name = lint.name.replace("_", "-");
-            println!(
-                "    {}  {:7.7}  {}",
-                padded(&scoped(&name)),
-                lint_level(lint),
-                lint.desc
-            );
-        }
-        println!("\n");
-    };
-
-    print_lints(&lints);
-
-    let max_group_name_len = std::cmp::max(
-        "clippy::all".len(),
-        lint_groups
-            .iter()
-            .map(|group| group.len())
-            .map(|len| len + "clippy::".len())
-            .max()
-            .unwrap_or(0),
-    );
-
-    let padded_group = |x: &str| {
-        let mut s = " ".repeat(max_group_name_len - x.chars().count());
-        s.push_str(x);
-        s
-    };
-
-    println!("Lint groups provided by clippy:\n");
-    println!("    {}  sub-lints", padded_group("name"));
-    println!("    {}  ---------", padded_group("----"));
-    println!("    {}  the set of all clippy lints", padded_group("clippy::all"));
-
-    let print_lint_groups = || {
-        for group in lint_groups {
-            let name = group.to_lowercase().replace("_", "-");
-            let desc = lints
-                .iter()
-                .filter(|&lint| lint.group == group)
-                .map(|lint| lint.name)
-                .map(|name| name.replace("_", "-"))
-                .collect::<Vec<String>>()
-                .join(", ");
-            println!("    {}  {}", padded_group(&scoped(&name)), desc);
-        }
-        println!("\n");
-    };
-
-    print_lint_groups();
-}
-
 fn display_help() {
     println!(
         "\
@@ -379,17 +269,6 @@ pub fn main() {
             exit(0);
         }
 
-        let should_describe_lints = || {
-            let args: Vec<_> = env::args().collect();
-            args.windows(2)
-                .any(|args| args[1] == "help" && matches!(args[0].as_str(), "-W" | "-A" | "-D" | "-F"))
-        };
-
-        if !wrapper_mode && should_describe_lints() {
-            describe_lints();
-            exit(0);
-        }
-
         // this conditional check for the --sysroot flag is there so users can call
         // `clippy_driver` directly
         // without having to pass --sysroot or anything