Add suspicious group

Author: camsteffen

README.md

@@ -10,16 +10,17 @@ A collection of lints to catch common mistakes and improve your [Rust](https://g
 Lints are divided into categories, each with a default [lint level](https://doc.rust-lang.org/rustc/lints/levels.html).
 You can choose how much Clippy is supposed to ~~annoy~~ help you by changing the lint level by category.
 
-| Category              | Description                                                             | Default level |
-| --------------------- | ----------------------------------------------------------------------- | ------------- |
-| `clippy::all`         | all lints that are on by default (correctness, style, complexity, perf) | **warn/deny** |
-| `clippy::correctness` | code that is outright wrong or very useless                             | **deny**      |
-| `clippy::style`       | code that should be written in a more idiomatic way                     | **warn**      |
-| `clippy::complexity`  | code that does something simple but in a complex way                    | **warn**      |
-| `clippy::perf`        | code that can be written to run faster                                  | **warn**      |
-| `clippy::pedantic`    | lints which are rather strict or might have false positives             | allow         |
-| `clippy::nursery`     | new lints that are still under development                              | allow         |
-| `clippy::cargo`       | lints for the cargo manifest                                            | allow         |
+| Category              | Description                                                                         | Default level |
+| --------------------- | ----------------------------------------------------------------------------------- | ------------- |
+| `clippy::all`         | all lints that are on by default (correctness, suspicious, style, complexity, perf) | **warn/deny** |
+| `clippy::correctness` | code that is outright wrong or useless                                              | **deny**      |
+| `clippy::suspicious`  | code that is most likely wrong or useless                                           | **warn**      |
+| `clippy::style`       | code that should be written in a more idiomatic way                                 | **warn**      |
+| `clippy::complexity`  | code that does something simple but in a complex way                                | **warn**      |
+| `clippy::perf`        | code that can be written to run faster                                              | **warn**      |
+| `clippy::pedantic`    | lints which are rather strict or might have false positives                         | allow         |
+| `clippy::nursery`     | new lints that are still under development                                          | allow         |
+| `clippy::cargo`       | lints for the cargo manifest                                                        | allow         |
 
 More to come, please [file an issue](https://github.com/rust-lang/rust-clippy/issues) if you have ideas!
 

clippy_dev/src/main.rs

@@ -137,6 +137,7 @@ fn get_clap_config<'a>() -> ArgMatches<'a> {
                         .possible_values(&[
                             "style",
                             "correctness",
+                            "suspicious",
                             "complexity",
                             "perf",
                             "pedantic",

clippy_dev/src/update_lints.rs

@@ -92,7 +92,10 @@ pub fn run(update_mode: UpdateMode) {
         || {
             // clippy::all should only include the following lint groups:
             let all_group_lints = usable_lints.iter().filter(|l| {
-                l.group == "correctness" || l.group == "style" || l.group == "complexity" || l.group == "perf"
+                matches!(
+                    &*l.group,
+                    "correctness" | "suspicious" | "style" | "complexity" | "perf"
+                )
             });
 
             gen_lint_group_list(all_group_lints)

clippy_lints/src/lib.rs

@@ -60,9 +60,9 @@ use rustc_session::Session;
 /// 4. The `description` that contains a short explanation on what's wrong with code where the
 ///    lint is triggered.
 ///
-/// Currently the categories `style`, `correctness`, `complexity` and `perf` are enabled by default.
-/// As said in the README.md of this repository, if the lint level mapping changes, please update
-/// README.md.
+/// Currently the categories `style`, `correctness`, `suspicious`, `complexity` and `perf` are
+/// enabled by default. As said in the README.md of this repository, if the lint level mapping
+/// changes, please update README.md.
 ///
 /// # Example
 ///
@@ -106,6 +106,11 @@ macro_rules! declare_clippy_lint {
             $(#[$attr])* pub clippy::$name, Deny, $description, report_in_external_macro: true
         }
     };
+    { $(#[$attr:meta])* pub $name:tt, suspicious, $description:tt } => {
+        declare_tool_lint! {
+            $(#[$attr])* pub clippy::$name, Warn, $description, report_in_external_macro: true
+        }
+    };
     { $(#[$attr:meta])* pub $name:tt, complexity, $description:tt } => {
         declare_tool_lint! {
             $(#[$attr])* pub clippy::$name, Warn, $description, report_in_external_macro: true

clippy_lints/src/utils/internal_lints/metadata_collector.rs

@@ -47,8 +47,9 @@ const DEPRECATED_LINT_GROUP_STR: &str = "deprecated";
 const DEPRECATED_LINT_LEVEL: &str = "none";
 /// This array holds Clippy's lint groups with their corresponding default lint level. The
 /// lint level for deprecated lints is set in `DEPRECATED_LINT_LEVEL`.
-const DEFAULT_LINT_LEVELS: [(&str, &str); 8] = [
+const DEFAULT_LINT_LEVELS: &[(&str, &str)] = &[
     ("correctness", "deny"),
+    ("suspicious", "warn"),
     ("restriction", "allow"),
     ("style", "warn"),
     ("pedantic", "allow"),

util/lintlib.py

@@ -19,6 +19,7 @@
 
 lint_levels = {
     "correctness": 'Deny',
+    "suspicious": 'Warn',
     "style": 'Warn',
     "complexity": 'Warn',
     "perf": 'Warn',