X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;ds=sidebyside;f=doc%2Fadding_lints.md;h=004eb28b44640fb59ab3d43c31203ab97c622870;hb=2a8d7bd0dd69ab1fe2a2af0f2984959f62b5631c;hp=99b86953d51a6287ceccb8bcb9207d881b0f368e;hpb=4be72b0936955b5820ca327fd9370303ccd9ef67;p=rust.git

diff --git a/doc/adding_lints.md b/doc/adding_lints.md
index 99b86953d51..004eb28b446 100644
--- a/doc/adding_lints.md
+++ b/doc/adding_lints.md
@@ -11,6 +11,7 @@ because that's clearly a non-descriptive name.
   - [Setup](#setup)
   - [Getting Started](#getting-started)
   - [Testing](#testing)
+    - [Cargo lints](#cargo-lints)
   - [Rustfix tests](#rustfix-tests)
   - [Edition 2018 tests](#edition-2018-tests)
   - [Testing manually](#testing-manually)
@@ -179,14 +180,11 @@ the auto-generated lint declaration to have a real description, something like t
 
 ```rust
 declare_clippy_lint! {
-    /// **What it does:**
+    /// ### What it does
     ///
-    /// **Why is this bad?**
-    ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
     ///
+    /// ### Example
     /// ```rust
     /// // example code
     /// ```
@@ -390,17 +388,23 @@ pass.
 
 ## Specifying the lint's minimum supported Rust version (MSRV)
 
-Projects supporting older versions of Rust would need to disable a lint if it
-targets features present in later versions. Support for this can be added by
-specifying an MSRV in your lint like so,
+Sometimes a lint makes suggestions that require a certain version of Rust. For example, the `manual_strip` lint suggests
+using `str::strip_prefix` and `str::strip_suffix` which is only available after Rust 1.45. In such cases, you need to
+ensure that the MSRV configured for the project is >= the MSRV of the required Rust feature. If multiple features are
+required, just use the one with a lower MSRV.
+
+First, add an MSRV alias for the required feature in [`clippy_utils::msrvs`](/clippy_utils/src/msrvs.rs). This can be
+accessed later as `msrvs::STR_STRIP_PREFIX`, for example.
 
 ```rust
-const MANUAL_STRIP_MSRV: RustcVersion = RustcVersion::new(1, 45, 0);
+msrv_aliases! {
+    ..
+    1,45,0 { STR_STRIP_PREFIX }
+}
 ```
 
-The project's MSRV will also have to be an attribute in the lint so you'll have
-to add a struct and constructor for your lint. The project's MSRV needs to be
-passed when the lint is registered in `lib.rs`
+In order to access the project-configured MSRV, you need to have an `msrv` field in the LintPass struct, and a
+constructor to initialize the field. The `msrv` value is passed to the constructor in `clippy_lints/lib.rs`.
 
 ```rust
 pub struct ManualStrip {
@@ -415,11 +419,11 @@ impl ManualStrip {
 }
 ```
 
-The project's MSRV can then be matched against the lint's `msrv` in the LintPass
+The project's MSRV can then be matched against the feature MSRV in the LintPass
 using the `meets_msrv` utility function.
 
 ``` rust
-if !meets_msrv(self.msrv.as_ref(), &MANUAL_STRIP_MSRV) {
+if !meets_msrv(self.msrv.as_ref(), &msrvs::STR_STRIP_PREFIX) {
     return;
 }
 ```
@@ -448,7 +452,7 @@ in `clippy_lints/src/utils/conf.rs`:
 ```rust
 define_Conf! {
     /// Lint: LIST, OF, LINTS, <THE_NEWLY_ADDED_LINT>. The minimum rust version that the project supports
-    (msrv, "msrv": Option<String>, None),
+    (msrv: Option<String> = None),
     ...
 }
 ```
@@ -481,13 +485,13 @@ Please document your lint with a doc comment akin to the following:
 
 ```rust
 declare_clippy_lint! {
-    /// **What it does:** Checks for ... (describe what the lint matches).
-    ///
-    /// **Why is this bad?** Supply the reason for linting the code.
+    /// ### What it does
+    /// Checks for ... (describe what the lint matches).
     ///
-    /// **Known problems:** None. (Or describe where it could go wrong.)
+    /// ### Why is this bad?
+    /// Supply the reason for linting the code.
     ///
-    /// **Example:**
+    /// ### Example
     ///
     /// ```rust,ignore
     /// // Bad
@@ -552,14 +556,15 @@ directory. Adding a configuration to a lint can be useful for thresholds or to c
 behavior that can be seen as a false positive for some users. Adding a configuration is done
 in the following steps:
 
-1. Adding a new configuration entry to [clippy_utils::conf](/clippy_utils/src/conf.rs)
+1. Adding a new configuration entry to [clippy_lints::utils::conf](/clippy_lints/src/utils/conf.rs)
     like this:
     ```rust
-    /// Lint: LINT_NAME. <The configuration field doc comment>
-    (configuration_ident, "configuration_value": Type, DefaultValue),
+    /// Lint: LINT_NAME.
+    ///
+    /// <The configuration field doc comment>
+    (configuration_ident: Type = DefaultValue),
     ```
-    The configuration value and identifier should usually be the same. The doc comment will be
-    automatically added to the lint documentation.
+    The doc comment will be automatically added to the lint documentation.
 2. Adding the configuration value to the lint impl struct:
     1. This first requires the definition of a lint impl struct. Lint impl structs are usually
         generated with the `declare_lint_pass!` macro. This struct needs to be defined manually
@@ -625,7 +630,7 @@ in the following steps:
 Here are some pointers to things you are likely going to need for every lint:
 
 * [Clippy utils][utils] - Various helper functions. Maybe the function you need
-  is already in here (`implements_trait`, `match_path`, `snippet`, etc)
+  is already in here (`implements_trait`, `match_def_path`, `snippet`, etc)
 * [Clippy diagnostics][diagnostics]
 * [The `if_chain` macro][if_chain]
 * [`from_expansion`][from_expansion] and [`in_external_macro`][in_external_macro]