Merge commit '0cce3f643bfcbb92d5a1bb71858c9cbaff749d6b' into clippyup

.github/deploy.sh

@@ -8,13 +8,12 @@ rm -rf out/master/ || exit 0
 echo "Making the docs for master"
 mkdir out/master/
 cp util/gh-pages/index.html out/master
-python3 ./util/export.py out/master/lints.json
+cp util/gh-pages/lints.json out/master
 
 if [[ -n $TAG_NAME ]]; then
   echo "Save the doc for the current tag ($TAG_NAME) and point stable/ to it"
-  cp -r out/master "out/$TAG_NAME"
-  rm -f out/stable
-  ln -s "$TAG_NAME" out/stable
+  cp -Tr out/master "out/$TAG_NAME"
+  ln -sf "$TAG_NAME" out/stable
 fi
 
 if [[ $BETA = "true" ]]; then
@@ -28,8 +27,8 @@ cp util/gh-pages/versions.html out/index.html
 echo "Making the versions.json file"
 python3 ./util/versions.py out
 
-cd out
 # Now let's go have some fun with the cloned repo
+cd out
 git config user.name "GHA CI"
 git config user.email "gha@ci.invalid"
 

.github/workflows/deploy.yml

@@ -39,10 +39,23 @@ jobs:
       if: github.ref == 'refs/heads/beta'
       run: echo "BETA=true" >> $GITHUB_ENV
 
-    - name: Use scripts and templates from master branch
+    # We need to check out all files that (transitively) depend on the
+    # structure of the gh-pages branch, so that we're able to change that
+    # structure without breaking the deployment.
+    - name: Use deploy files from master branch
       run: |
         git fetch --no-tags --prune --depth=1 origin master
-        git checkout origin/master -- .github/deploy.sh util/gh-pages/ util/*.py
+        git checkout origin/master -- .github/deploy.sh util/versions.py util/gh-pages/versions.html
+
+    # Generate lockfile for caching to avoid build problems with cached deps
+    - name: cargo generate-lockfile
+      run: cargo generate-lockfile
+
+    - name: Cache
+      uses: Swatinem/rust-cache@v1.3.0
+
+    - name: cargo collect-metadata
+      run: cargo collect-metadata
 
     - name: Deploy
       run: |

CHANGELOG.md

@@ -2423,7 +2423,6 @@ Released 2018-09-13
 <!-- begin autogenerated links to lint list -->
 [`absurd_extreme_comparisons`]: https://rust-lang.github.io/rust-clippy/master/index.html#absurd_extreme_comparisons
 [`almost_swapped`]: https://rust-lang.github.io/rust-clippy/master/index.html#almost_swapped
-[`append_instead_of_extend`]: https://rust-lang.github.io/rust-clippy/master/index.html#append_instead_of_extend
 [`approx_constant`]: https://rust-lang.github.io/rust-clippy/master/index.html#approx_constant
 [`as_conversions`]: https://rust-lang.github.io/rust-clippy/master/index.html#as_conversions
 [`assertions_on_constants`]: https://rust-lang.github.io/rust-clippy/master/index.html#assertions_on_constants
@@ -2522,6 +2521,7 @@ Released 2018-09-13
 [`explicit_iter_loop`]: https://rust-lang.github.io/rust-clippy/master/index.html#explicit_iter_loop
 [`explicit_write`]: https://rust-lang.github.io/rust-clippy/master/index.html#explicit_write
 [`extend_from_slice`]: https://rust-lang.github.io/rust-clippy/master/index.html#extend_from_slice
+[`extend_with_drain`]: https://rust-lang.github.io/rust-clippy/master/index.html#extend_with_drain
 [`extra_unused_lifetimes`]: https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_lifetimes
 [`fallible_impl_from`]: https://rust-lang.github.io/rust-clippy/master/index.html#fallible_impl_from
 [`field_reassign_with_default`]: https://rust-lang.github.io/rust-clippy/master/index.html#field_reassign_with_default
@@ -2772,7 +2772,7 @@ Released 2018-09-13
 [`same_item_push`]: https://rust-lang.github.io/rust-clippy/master/index.html#same_item_push
 [`search_is_some`]: https://rust-lang.github.io/rust-clippy/master/index.html#search_is_some
 [`self_assignment`]: https://rust-lang.github.io/rust-clippy/master/index.html#self_assignment
-[`self_named_constructor`]: https://rust-lang.github.io/rust-clippy/master/index.html#self_named_constructor
+[`self_named_constructors`]: https://rust-lang.github.io/rust-clippy/master/index.html#self_named_constructors
 [`semicolon_if_nothing_returned`]: https://rust-lang.github.io/rust-clippy/master/index.html#semicolon_if_nothing_returned
 [`serde_api_misuse`]: https://rust-lang.github.io/rust-clippy/master/index.html#serde_api_misuse
 [`shadow_reuse`]: https://rust-lang.github.io/rust-clippy/master/index.html#shadow_reuse

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "clippy"
-version = "0.1.55"
+version = "0.1.56"
 authors = ["The Rust Clippy Developers"]
 description = "A bunch of helpful lints to avoid common pitfalls in Rust"
 repository = "https://github.com/rust-lang/rust-clippy"

clippy_dev/src/new_lint.rs

@@ -169,14 +169,11 @@ use rustc_session::{{declare_lint_pass, declare_tool_lint}};
 {pass_import}
 
 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 where clippy issues a warning
     /// ```

clippy_dev/src/serve.rs

@@ -15,8 +15,8 @@ pub fn run(port: u16, lint: Option<&str>) -> ! {
 
     loop {
         if mtime("util/gh-pages/lints.json") < mtime("clippy_lints/src") {
-            Command::new("python3")
-                .arg("util/export.py")
+            Command::new("cargo")
+                .arg("collect-metadata")
                 .spawn()
                 .unwrap()
                 .wait()

clippy_lints/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "clippy_lints"
 # begin automatic update
-version = "0.1.55"
+version = "0.1.56"
 # end automatic update
 authors = ["The Rust Clippy Developers"]
 description = "A bunch of helpful lints to avoid common pitfalls in Rust"

clippy_lints/src/absurd_extreme_comparisons.rs

@@ -11,24 +11,26 @@ use clippy_utils::ty::is_isize_or_usize;
 use clippy_utils::{clip, int_bits, unsext};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for comparisons where one side of the relation is
+    /// ### What it does
+    /// Checks for comparisons where one side of the relation is
     /// either the minimum or maximum value for its type and warns if it involves a
     /// case that is always true or always false. Only integer and boolean types are
     /// checked.
     ///
-    /// **Why is this bad?** An expression like `min <= x` may misleadingly imply
+    /// ### Why is this bad?
+    /// An expression like `min <= x` may misleadingly imply
     /// that it is possible for `x` to be less than the minimum. Expressions like
     /// `max < x` are probably mistakes.
     ///
-    /// **Known problems:** For `usize` the size of the current compile target will
+    /// ### Known problems
+    /// For `usize` the size of the current compile target will
     /// be assumed (e.g., 64 bits on 64 bit systems). This means code that uses such
     /// a comparison to detect target pointer width will trigger this lint. One can
     /// use `mem::sizeof` and compare its value or conditional compilation
     /// attributes
     /// like `#[cfg(target_pointer_width = "64")] ..` instead.
     ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// let vec: Vec<isize> = Vec::new();
     /// if vec.len() <= 0 {}

clippy_lints/src/approx_const.rs

@@ -7,21 +7,21 @@ use rustc_span::symbol;
 use std::f64::consts as f64;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for floating point literals that approximate
+    /// ### What it does
+    /// Checks for floating point literals that approximate
     /// constants which are defined in
     /// [`std::f32::consts`](https://doc.rust-lang.org/stable/std/f32/consts/#constants)
     /// or
     /// [`std::f64::consts`](https://doc.rust-lang.org/stable/std/f64/consts/#constants),
     /// respectively, suggesting to use the predefined constant.
     ///
-    /// **Why is this bad?** Usually, the definition in the standard library is more
+    /// ### Why is this bad?
+    /// Usually, the definition in the standard library is more
     /// precise than what people come up with. If you find that your definition is
     /// actually more precise, please [file a Rust
     /// issue](https://github.com/rust-lang/rust/issues).
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let x = 3.14;
     /// let y = 1_f64 / x;

clippy_lints/src/arithmetic.rs

@@ -6,7 +6,8 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for integer arithmetic operations which could overflow or panic.
+    /// ### What it does
+    /// Checks for integer arithmetic operations which could overflow or panic.
     ///
     /// Specifically, checks for any operators (`+`, `-`, `*`, `<<`, etc) which are capable
     /// of overflowing according to the [Rust
@@ -14,13 +15,12 @@ declare_clippy_lint! {
     /// or which can panic (`/`, `%`). No bounds analysis or sophisticated reasoning is
     /// attempted.
     ///
-    /// **Why is this bad?** Integer overflow will trigger a panic in debug builds or will wrap in
+    /// ### Why is this bad?
+    /// Integer overflow will trigger a panic in debug builds or will wrap in
     /// release mode. Division by zero will cause a panic in either mode. In some applications one
     /// wants explicitly checked, wrapping or saturating arithmetic.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let a = 0;
     /// a + 1;
@@ -31,14 +31,14 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for float arithmetic.
+    /// ### What it does
+    /// Checks for float arithmetic.
     ///
-    /// **Why is this bad?** For some embedded systems or kernel development, it
+    /// ### Why is this bad?
+    /// For some embedded systems or kernel development, it
     /// can be useful to rule out floating-point numbers.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let a = 0.0;
     /// a + 1.0;

clippy_lints/src/as_conversions.rs

@@ -5,7 +5,8 @@ use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of `as` conversions.
+    /// ### What it does
+    /// Checks for usage of `as` conversions.
     ///
     /// Note that this lint is specialized in linting *every single* use of `as`
     /// regardless of whether good alternatives exist or not.
@@ -15,14 +16,13 @@ declare_clippy_lint! {
     /// There is a good explanation the reason why this lint should work in this way and how it is useful
     /// [in this issue](https://github.com/rust-lang/rust-clippy/issues/5122).
     ///
-    /// **Why is this bad?** `as` conversions will perform many kinds of
+    /// ### Why is this bad?
+    /// `as` conversions will perform many kinds of
     /// conversions, including silently lossy conversions and dangerous coercions.
     /// There are cases when it makes sense to use `as`, so the lint is
     /// Allow by default.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// let a: u32;
     /// ...

clippy_lints/src/asm_syntax.rs

@@ -53,14 +53,14 @@ fn check_expr_asm_syntax(lint: &'static Lint, cx: &EarlyContext<'_>, expr: &Expr
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of Intel x86 assembly syntax.
+    /// ### What it does
+    /// Checks for usage of Intel x86 assembly syntax.
     ///
-    /// **Why is this bad?** The lint has been enabled to indicate a preference
+    /// ### Why is this bad?
+    /// The lint has been enabled to indicate a preference
     /// for AT&T x86 assembly syntax.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     ///
     /// ```rust,no_run
     /// # #![feature(asm)]
@@ -89,14 +89,14 @@ impl EarlyLintPass for InlineAsmX86IntelSyntax {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of AT&T x86 assembly syntax.
+    /// ### What it does
+    /// Checks for usage of AT&T x86 assembly syntax.
     ///
-    /// **Why is this bad?** The lint has been enabled to indicate a preference
+    /// ### Why is this bad?
+    /// The lint has been enabled to indicate a preference
     /// for Intel x86 assembly syntax.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     ///
     /// ```rust,no_run
     /// # #![feature(asm)]

clippy_lints/src/assertions_on_constants.rs

@@ -8,14 +8,17 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `assert!(true)` and `assert!(false)` calls.
+    /// ### What it does
+    /// Checks for `assert!(true)` and `assert!(false)` calls.
     ///
-    /// **Why is this bad?** Will be optimized out by the compiler or should probably be replaced by a
+    /// ### Why is this bad?
+    /// Will be optimized out by the compiler or should probably be replaced by a
     /// `panic!()` or `unreachable!()`
     ///
-    /// **Known problems:** None
+    /// ### Known problems
+    /// None
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// assert!(false)
     /// assert!(true)

clippy_lints/src/assign_ops.rs

@@ -12,15 +12,18 @@ use rustc_middle::hir::map::Map;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `a = a op b` or `a = b commutative_op a`
+    /// ### What it does
+    /// Checks for `a = a op b` or `a = b commutative_op a`
     /// patterns.
     ///
-    /// **Why is this bad?** These can be written as the shorter `a op= b`.
+    /// ### Why is this bad?
+    /// These can be written as the shorter `a op= b`.
     ///
-    /// **Known problems:** While forbidden by the spec, `OpAssign` traits may have
+    /// ### Known problems
+    /// While forbidden by the spec, `OpAssign` traits may have
     /// implementations that differ from the regular `Op` impl.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let mut a = 5;
     /// let b = 0;
@@ -37,17 +40,20 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `a op= a op b` or `a op= b op a` patterns.
+    /// ### What it does
+    /// Checks for `a op= a op b` or `a op= b op a` patterns.
     ///
-    /// **Why is this bad?** Most likely these are bugs where one meant to write `a
+    /// ### Why is this bad?
+    /// Most likely these are bugs where one meant to write `a
     /// op= b`.
     ///
-    /// **Known problems:** Clippy cannot know for sure if `a op= a op b` should have
+    /// ### Known problems
+    /// Clippy cannot know for sure if `a op= a op b` should have
     /// been `a = a op a op b` or `a = a op b`/`a op= b`. Therefore, it suggests both.
     /// If `a op= a op b` is really the correct behaviour it should be
     /// written as `a = a op a op b` as it's less confusing.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let mut a = 5;
     /// let b = 2;

clippy_lints/src/async_yields_async.rs

@@ -7,15 +7,14 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for async blocks that yield values of types
+    /// ### What it does
+    /// Checks for async blocks that yield values of types
     /// that can themselves be awaited.
     ///
-    /// **Why is this bad?** An await is likely missing.
-    ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// An await is likely missing.
     ///
+    /// ### Example
     /// ```rust
     /// async fn foo() {}
     ///

clippy_lints/src/atomic_ordering.rs

@@ -8,16 +8,16 @@ use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of invalid atomic
+    /// ### What it does
+    /// Checks for usage of invalid atomic
     /// ordering in atomic loads/stores/exchanges/updates and
     /// memory fences.
     ///
-    /// **Why is this bad?** Using an invalid atomic ordering
+    /// ### Why is this bad?
+    /// Using an invalid atomic ordering
     /// will cause a panic at run-time.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,no_run
     /// # use std::sync::atomic::{self, AtomicU8, Ordering};
     ///

clippy_lints/src/attrs.rs

@@ -41,10 +41,12 @@ static UNIX_SYSTEMS: &[&str] = &[
 static NON_UNIX_SYSTEMS: &[&str] = &["hermit", "none", "wasi"];
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for items annotated with `#[inline(always)]`,
+    /// ### What it does
+    /// Checks for items annotated with `#[inline(always)]`,
     /// unless the annotated function is empty or simply panics.
     ///
-    /// **Why is this bad?** While there are valid uses of this annotation (and once
+    /// ### Why is this bad?
+    /// While there are valid uses of this annotation (and once
     /// you know when to use it, by all means `allow` this lint), it's a common
     /// newbie-mistake to pepper one's code with it.
     ///
@@ -52,11 +54,12 @@ declare_clippy_lint! {
     /// measure if that additional function call really affects your runtime profile
     /// sufficiently to make up for the increase in compile time.
     ///
-    /// **Known problems:** False positives, big time. This lint is meant to be
+    /// ### Known problems
+    /// False positives, big time. This lint is meant to be
     /// deactivated by everyone doing serious performance work. This means having
     /// done the measurement.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// #[inline(always)]
     /// fn not_quite_hot_code(..) { ... }
@@ -67,7 +70,8 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `extern crate` and `use` items annotated with
+    /// ### What it does
+    /// Checks for `extern crate` and `use` items annotated with
     /// lint attributes.
     ///
     /// This lint permits `#[allow(unused_imports)]`, `#[allow(deprecated)]`,
@@ -75,12 +79,11 @@ declare_clippy_lint! {
     /// `#[allow(clippy::enum_glob_use)]` on `use` items and `#[allow(unused_imports)]` on
     /// `extern crate` items with a `#[macro_use]` attribute.
     ///
-    /// **Why is this bad?** Lint attributes have no effect on crate imports. Most
+    /// ### Why is this bad?
+    /// Lint attributes have no effect on crate imports. Most
     /// likely a `!` was forgotten.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// // Bad
     /// #[deny(dead_code)]
@@ -101,15 +104,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `#[deprecated]` annotations with a `since`
+    /// ### What it does
+    /// Checks for `#[deprecated]` annotations with a `since`
     /// field that is not a valid semantic version.
     ///
-    /// **Why is this bad?** For checking the version of the deprecation, it must be
+    /// ### Why is this bad?
+    /// For checking the version of the deprecation, it must be
     /// a valid semver. Failing that, the contained information is useless.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// #[deprecated(since = "forever")]
     /// fn something_else() { /* ... */ }
@@ -120,20 +123,22 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for empty lines after outer attributes
+    /// ### What it does
+    /// Checks for empty lines after outer attributes
     ///
-    /// **Why is this bad?**
+    /// ### Why is this bad?
     /// Most likely the attribute was meant to be an inner attribute using a '!'.
     /// If it was meant to be an outer attribute, then the following item
     /// should not be separated by empty lines.
     ///
-    /// **Known problems:** Can cause false positives.
+    /// ### Known problems
+    /// Can cause false positives.
     ///
     /// From the clippy side it's difficult to detect empty lines between an attributes and the
     /// following item because empty lines and comments are not part of the AST. The parsing
     /// currently works for basic cases but is not perfect.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// // Good (as inner attribute)
     /// #![allow(dead_code)]
@@ -155,14 +160,14 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `warn`/`deny`/`forbid` attributes targeting the whole clippy::restriction category.
+    /// ### What it does
+    /// Checks for `warn`/`deny`/`forbid` attributes targeting the whole clippy::restriction category.
     ///
-    /// **Why is this bad?** Restriction lints sometimes are in contrast with other lints or even go against idiomatic rust.
+    /// ### Why is this bad?
+    /// Restriction lints sometimes are in contrast with other lints or even go against idiomatic rust.
     /// These lints should only be enabled on a lint-by-lint basis and with careful consideration.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// Bad:
     /// ```rust
     /// #![deny(clippy::restriction)]
@@ -178,18 +183,20 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `#[cfg_attr(rustfmt, rustfmt_skip)]` and suggests to replace it
+    /// ### What it does
+    /// Checks for `#[cfg_attr(rustfmt, rustfmt_skip)]` and suggests to replace it
     /// with `#[rustfmt::skip]`.
     ///
-    /// **Why is this bad?** Since tool_attributes ([rust-lang/rust#44690](https://github.com/rust-lang/rust/issues/44690))
+    /// ### Why is this bad?
+    /// Since tool_attributes ([rust-lang/rust#44690](https://github.com/rust-lang/rust/issues/44690))
     /// are stable now, they should be used instead of the old `cfg_attr(rustfmt)` attributes.
     ///
-    /// **Known problems:** This lint doesn't detect crate level inner attributes, because they get
+    /// ### Known problems
+    /// This lint doesn't detect crate level inner attributes, because they get
     /// processed before the PreExpansionPass lints get executed. See
     /// [#3123](https://github.com/rust-lang/rust-clippy/pull/3123#issuecomment-422321765)
     ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// Bad:
     /// ```rust
     /// #[cfg_attr(rustfmt, rustfmt_skip)]
@@ -207,15 +214,14 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for cfg attributes having operating systems used in target family position.
+    /// ### What it does
+    /// Checks for cfg attributes having operating systems used in target family position.
     ///
-    /// **Why is this bad?** The configuration option will not be recognised and the related item will not be included
+    /// ### Why is this bad?
+    /// The configuration option will not be recognised and the related item will not be included
     /// by the conditional compilation engine.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// Bad:
     /// ```rust
     /// #[cfg(linux)]

clippy_lints/src/await_holding_invalid.rs

@@ -8,10 +8,12 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for calls to await while holding a
+    /// ### What it does
+    /// Checks for calls to await while holding a
     /// non-async-aware MutexGuard.
     ///
-    /// **Why is this bad?** The Mutex types found in std::sync and parking_lot
+    /// ### Why is this bad?
+    /// The Mutex types found in std::sync and parking_lot
     /// are not designed to operate in an async context across await points.
     ///
     /// There are two potential solutions. One is to use an asynx-aware Mutex
@@ -19,10 +21,10 @@ declare_clippy_lint! {
     /// other solution is to ensure the mutex is unlocked before calling await,
     /// either by introducing a scope or an explicit call to Drop::drop.
     ///
-    /// **Known problems:** Will report false positive for explicitly dropped guards ([#6446](https://github.com/rust-lang/rust-clippy/issues/6446)).
-    ///
-    /// **Example:**
+    /// ### Known problems
+    /// Will report false positive for explicitly dropped guards ([#6446](https://github.com/rust-lang/rust-clippy/issues/6446)).
     ///
+    /// ### Example
     /// ```rust,ignore
     /// use std::sync::Mutex;
     ///
@@ -51,17 +53,19 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for calls to await while holding a
+    /// ### What it does
+    /// Checks for calls to await while holding a
     /// `RefCell` `Ref` or `RefMut`.
     ///
-    /// **Why is this bad?** `RefCell` refs only check for exclusive mutable access
+    /// ### Why is this bad?
+    /// `RefCell` refs only check for exclusive mutable access
     /// at runtime. Holding onto a `RefCell` ref across an `await` suspension point
     /// risks panics from a mutable ref shared while other refs are outstanding.
     ///
-    /// **Known problems:** Will report false positive for explicitly dropped refs ([#6353](https://github.com/rust-lang/rust-clippy/issues/6353)).
-    ///
-    /// **Example:**
+    /// ### Known problems
+    /// Will report false positive for explicitly dropped refs ([#6353](https://github.com/rust-lang/rust-clippy/issues/6353)).
     ///
+    /// ### Example
     /// ```rust,ignore
     /// use std::cell::RefCell;
     ///

clippy_lints/src/bit_mask.rs

@@ -10,7 +10,8 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for incompatible bit masks in comparisons.
+    /// ### What it does
+    /// Checks for incompatible bit masks in comparisons.
     ///
     /// The formula for detecting if an expression of the type `_ <bit_op> m
     /// <cmp_op> c` (where `<bit_op>` is one of {`&`, `|`} and `<cmp_op>` is one of
@@ -26,7 +27,8 @@ declare_clippy_lint! {
     /// |`<`  or `>=`| `|`  |`x | 1 < 1` |`false`  |`m >= c`              |
     /// |`<=` or `>` | `|`  |`x | 1 > 0` |`true`   |`m > c`               |
     ///
-    /// **Why is this bad?** If the bits that the comparison cares about are always
+    /// ### Why is this bad?
+    /// If the bits that the comparison cares about are always
     /// set to zero or one by the bit mask, the comparison is constant `true` or
     /// `false` (depending on mask, compared value, and operators).
     ///
@@ -34,9 +36,7 @@ declare_clippy_lint! {
     /// this intentionally is to win an underhanded Rust contest or create a
     /// test-case for this lint.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let x = 1;
     /// if (x & 1 == 2) { }
@@ -47,7 +47,8 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for bit masks in comparisons which can be removed
+    /// ### What it does
+    /// Checks for bit masks in comparisons which can be removed
     /// without changing the outcome. The basic structure can be seen in the
     /// following table:
     ///
@@ -56,16 +57,18 @@ declare_clippy_lint! {
     /// |`>` / `<=`|`|` / `^`|`x | 2 > 3`|`x > 3`|
     /// |`<` / `>=`|`|` / `^`|`x ^ 1 < 4`|`x < 4`|
     ///
-    /// **Why is this bad?** Not equally evil as [`bad_bit_mask`](#bad_bit_mask),
+    /// ### Why is this bad?
+    /// Not equally evil as [`bad_bit_mask`](#bad_bit_mask),
     /// but still a bit misleading, because the bit mask is ineffective.
     ///
-    /// **Known problems:** False negatives: This lint will only match instances
+    /// ### Known problems
+    /// False negatives: This lint will only match instances
     /// where we have figured out the math (which is for a power-of-two compared
     /// value). This means things like `x | 1 >= 7` (which would be better written
     /// as `x >= 6`) will not be reported (but bit masks like this are fairly
     /// uncommon).
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let x = 1;
     /// if (x | 1 > 3) {  }
@@ -76,15 +79,18 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for bit masks that can be replaced by a call
+    /// ### What it does
+    /// Checks for bit masks that can be replaced by a call
     /// to `trailing_zeros`
     ///
-    /// **Why is this bad?** `x.trailing_zeros() > 4` is much clearer than `x & 15
+    /// ### Why is this bad?
+    /// `x.trailing_zeros() > 4` is much clearer than `x & 15
     /// == 0`
     ///
-    /// **Known problems:** llvm generates better code for `x & 15 == 0` on x86
+    /// ### Known problems
+    /// llvm generates better code for `x & 15 == 0` on x86
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let x = 1;
     /// if x & 0b1111 == 0 { }

clippy_lints/src/blacklisted_name.rs

@@ -5,15 +5,15 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of blacklisted names for variables, such
+    /// ### What it does
+    /// Checks for usage of blacklisted names for variables, such
     /// as `foo`.
     ///
-    /// **Why is this bad?** These names are usually placeholder names and should be
+    /// ### Why is this bad?
+    /// These names are usually placeholder names and should be
     /// avoided.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let foo = 3.14;
     /// ```

clippy_lints/src/blocks_in_if_conditions.rs

@@ -13,14 +13,14 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `if` conditions that use blocks containing an
+    /// ### What it does
+    /// Checks for `if` conditions that use blocks containing an
     /// expression, statements or conditions that use closures with blocks.
     ///
-    /// **Why is this bad?** Style, using blocks in the condition makes it hard to read.
+    /// ### Why is this bad?
+    /// Style, using blocks in the condition makes it hard to read.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Examples:**
+    /// ### Examples
     /// ```rust
     /// // Bad
     /// if { true } { /* ... */ }

clippy_lints/src/bool_assert_comparison.rs

@@ -6,14 +6,13 @@ use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** This lint warns about boolean comparisons in assert-like macros.
+    /// ### What it does
+    /// This lint warns about boolean comparisons in assert-like macros.
     ///
-    /// **Why is this bad?** It is shorter to use the equivalent.
-    ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// It is shorter to use the equivalent.
     ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// assert_eq!("a".is_empty(), false);

clippy_lints/src/booleans.rs

@@ -14,16 +14,19 @@ use rustc_span::source_map::Span;
 use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for boolean expressions that can be written more
+    /// ### What it does
+    /// Checks for boolean expressions that can be written more
     /// concisely.
     ///
-    /// **Why is this bad?** Readability of boolean expressions suffers from
+    /// ### Why is this bad?
+    /// Readability of boolean expressions suffers from
     /// unnecessary duplication.
     ///
-    /// **Known problems:** Ignores short circuiting behavior of `||` and
+    /// ### Known problems
+    /// Ignores short circuiting behavior of `||` and
     /// `&&`. Ignores `|`, `&` and `^`.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// if a && true  // should be: if a
     /// if !(a == b)  // should be: if a != b
@@ -34,14 +37,17 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for boolean expressions that contain terminals that
+    /// ### What it does
+    /// Checks for boolean expressions that contain terminals that
     /// can be eliminated.
     ///
-    /// **Why is this bad?** This is most likely a logic bug.
+    /// ### Why is this bad?
+    /// This is most likely a logic bug.
     ///
-    /// **Known problems:** Ignores short circuiting behavior.
+    /// ### Known problems
+    /// Ignores short circuiting behavior.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// if a && b || a { ... }
     /// ```

clippy_lints/src/bytecount.rs

@@ -12,18 +12,20 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for naive byte counts
+    /// ### What it does
+    /// Checks for naive byte counts
     ///
-    /// **Why is this bad?** The [`bytecount`](https://crates.io/crates/bytecount)
+    /// ### Why is this bad?
+    /// The [`bytecount`](https://crates.io/crates/bytecount)
     /// crate has methods to count your bytes faster, especially for large slices.
     ///
-    /// **Known problems:** If you have predominantly small slices, the
+    /// ### Known problems
+    /// If you have predominantly small slices, the
     /// `bytecount::count(..)` method may actually be slower. However, if you can
     /// ensure that less than 2³²-1 matches arise, the `naive_count_32(..)` can be
     /// faster in those cases.
     ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// # let vec = vec![1_u8];
     /// &vec.iter().filter(|x| **x == 0u8).count(); // use bytecount::count instead

clippy_lints/src/cargo_common_metadata.rs

@@ -9,15 +9,15 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::DUMMY_SP;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks to see if all common metadata is defined in
+    /// ### What it does
+    /// Checks to see if all common metadata is defined in
     /// `Cargo.toml`. See: https://rust-lang-nursery.github.io/api-guidelines/documentation.html#cargotoml-includes-all-common-metadata-c-metadata
     ///
-    /// **Why is this bad?** It will be more difficult for users to discover the
+    /// ### Why is this bad?
+    /// It will be more difficult for users to discover the
     /// purpose of the crate, and key information related to it.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```toml
     /// # This `Cargo.toml` is missing a description field:
     /// [package]

clippy_lints/src/case_sensitive_file_extension_comparisons.rs

@@ -8,17 +8,14 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{source_map::Spanned, symbol::sym, Span};
 
 declare_clippy_lint! {
-    /// **What it does:**
+    /// ### What it does
     /// Checks for calls to `ends_with` with possible file extensions
     /// and suggests to use a case-insensitive approach instead.
     ///
-    /// **Why is this bad?**
+    /// ### Why is this bad?
     /// `ends_with` is case-sensitive and may not detect files with a valid extension.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// fn is_rust_file(filename: &str) -> bool {
     ///     filename.ends_with(".rs")

clippy_lints/src/casts/mod.rs

@@ -20,7 +20,8 @@ use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts from any numerical to a float type where
+    /// ### What it does
+    /// Checks for casts from any numerical to a float type where
     /// the receiving type cannot store all values from the original type without
     /// rounding errors. This possible rounding is to be expected, so this lint is
     /// `Allow` by default.
@@ -28,13 +29,12 @@ declare_clippy_lint! {
     /// Basically, this warns on casting any integer with 32 or more bits to `f32`
     /// or any 64-bit integer to `f64`.
     ///
-    /// **Why is this bad?** It's not bad at all. But in some applications it can be
+    /// ### Why is this bad?
+    /// It's not bad at all. But in some applications it can be
     /// helpful to know where precision loss can take place. This lint can help find
     /// those places in the code.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let x = u64::MAX;
     /// x as f64;
@@ -45,17 +45,17 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts from a signed to an unsigned numerical
+    /// ### What it does
+    /// Checks for casts from a signed to an unsigned numerical
     /// type. In this case, negative values wrap around to large positive values,
     /// which can be quite surprising in practice. However, as the cast works as
     /// defined, this lint is `Allow` by default.
     ///
-    /// **Why is this bad?** Possibly surprising results. You can activate this lint
+    /// ### Why is this bad?
+    /// Possibly surprising results. You can activate this lint
     /// as a one-time check to see where numerical wrapping can arise.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let y: i8 = -1;
     /// y as u128; // will return 18446744073709551615
@@ -66,17 +66,17 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts between numerical types that may
+    /// ### What it does
+    /// Checks for casts between numerical types that may
     /// truncate large values. This is expected behavior, so the cast is `Allow` by
     /// default.
     ///
-    /// **Why is this bad?** In some problem domains, it is good practice to avoid
+    /// ### Why is this bad?
+    /// In some problem domains, it is good practice to avoid
     /// truncation. This lint can be activated to help assess where additional
     /// checks could be beneficial.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// fn as_u8(x: u64) -> u8 {
     ///     x as u8
@@ -88,20 +88,20 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts from an unsigned type to a signed type of
+    /// ### What it does
+    /// Checks for casts from an unsigned type to a signed type of
     /// the same size. Performing such a cast is a 'no-op' for the compiler,
     /// i.e., nothing is changed at the bit level, and the binary representation of
     /// the value is reinterpreted. This can cause wrapping if the value is too big
     /// for the target signed type. However, the cast works as defined, so this lint
     /// is `Allow` by default.
     ///
-    /// **Why is this bad?** While such a cast is not bad in itself, the results can
+    /// ### Why is this bad?
+    /// While such a cast is not bad in itself, the results can
     /// be surprising when this is not the intended behavior, as demonstrated by the
     /// example below.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// u32::MAX as i32; // will yield a value of `-1`
     /// ```
@@ -111,19 +111,19 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts between numerical types that may
+    /// ### What it does
+    /// Checks for casts between numerical types that may
     /// be replaced by safe conversion functions.
     ///
-    /// **Why is this bad?** Rust's `as` keyword will perform many kinds of
+    /// ### Why is this bad?
+    /// Rust's `as` keyword will perform many kinds of
     /// conversions, including silently lossy conversions. Conversion functions such
     /// as `i32::from` will only perform lossless conversions. Using the conversion
     /// functions prevents conversions from turning into silent lossy conversions if
     /// the types of the input expressions ever change, and make it easier for
     /// people reading the code to know that the conversion is lossless.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// fn as_u64(x: u8) -> u64 {
     ///     x as u64
@@ -143,14 +143,14 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts to the same type, casts of int literals to integer types
+    /// ### What it does
+    /// Checks for casts to the same type, casts of int literals to integer types
     /// and casts of float literals to float types.
     ///
-    /// **Why is this bad?** It's just unnecessary.
+    /// ### Why is this bad?
+    /// It's just unnecessary.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let _ = 2i32 as i32;
     /// let _ = 0.5 as f32;
@@ -168,17 +168,20 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts, using `as` or `pointer::cast`,
+    /// ### What it does
+    /// Checks for casts, using `as` or `pointer::cast`,
     /// from a less-strictly-aligned pointer to a more-strictly-aligned pointer
     ///
-    /// **Why is this bad?** Dereferencing the resulting pointer may be undefined
+    /// ### Why is this bad?
+    /// Dereferencing the resulting pointer may be undefined
     /// behavior.
     ///
-    /// **Known problems:** Using `std::ptr::read_unaligned` and `std::ptr::write_unaligned` or similar
+    /// ### Known problems
+    /// Using `std::ptr::read_unaligned` and `std::ptr::write_unaligned` or similar
     /// on the resulting pointer is fine. Is over-zealous: Casts with manual alignment checks or casts like
     /// u64-> u8 -> u16 can be fine. Miri is able to do a more in-depth analysis.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let _ = (&1u8 as *const u8) as *const u16;
     /// let _ = (&mut 1u8 as *mut u8) as *mut u16;
@@ -192,9 +195,10 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts of function pointers to something other than usize
+    /// ### What it does
+    /// Checks for casts of function pointers to something other than usize
     ///
-    /// **Why is this bad?**
+    /// ### Why is this bad?
     /// Casting a function pointer to anything other than usize/isize is not portable across
     /// architectures, because you end up losing bits if the target type is too small or end up with a
     /// bunch of extra bits that waste space and add more instructions to the final binary than
@@ -202,8 +206,7 @@ declare_clippy_lint! {
     ///
     /// Casting to isize also doesn't make sense since there are no signed addresses.
     ///
-    /// **Example**
-    ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// fn fun() -> i32 { 1 }
@@ -219,16 +222,16 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts of a function pointer to a numeric type not wide enough to
+    /// ### What it does
+    /// Checks for casts of a function pointer to a numeric type not wide enough to
     /// store address.
     ///
-    /// **Why is this bad?**
+    /// ### Why is this bad?
     /// Such a cast discards some bits of the function's address. If this is intended, it would be more
     /// clearly expressed by casting to usize first, then casting the usize to the intended type (with
     /// a comment) to perform the truncation.
     ///
-    /// **Example**
-    ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// fn fn1() -> i16 {
@@ -249,15 +252,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for casts of `&T` to `&mut T` anywhere in the code.
+    /// ### What it does
+    /// Checks for casts of `&T` to `&mut T` anywhere in the code.
     ///
-    /// **Why is this bad?** It’s basically guaranteed to be undefined behaviour.
+    /// ### Why is this bad?
+    /// It’s basically guaranteed to be undefined behaviour.
     /// `UnsafeCell` is the only way to obtain aliasable data that is considered
     /// mutable.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// fn x(r: &i32) {
     ///     unsafe {
@@ -283,18 +286,18 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for expressions where a character literal is cast
+    /// ### What it does
+    /// Checks for expressions where a character literal is cast
     /// to `u8` and suggests using a byte literal instead.
     ///
-    /// **Why is this bad?** In general, casting values to smaller types is
+    /// ### Why is this bad?
+    /// In general, casting values to smaller types is
     /// error-prone and should be avoided where possible. In the particular case of
     /// converting a character literal to u8, it is easy to avoid by just using a
     /// byte literal instead. As an added bonus, `b'a'` is even slightly shorter
     /// than `'a' as u8`.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// 'x' as u8
     /// ```
@@ -310,18 +313,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:**
+    /// ### What it does
     /// Checks for `as` casts between raw pointers without changing its mutability,
     /// namely `*const T` to `*const U` and `*mut T` to `*mut U`.
     ///
-    /// **Why is this bad?**
+    /// ### Why is this bad?
     /// Though `as` casts between raw pointers is not terrible, `pointer::cast` is safer because
     /// it cannot accidentally change the pointer's mutability nor cast the pointer to other types like `usize`.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// let ptr: *const u32 = &42_u32;
     /// let mut_ptr: *mut u32 = &mut 42_u32;

clippy_lints/src/checked_conversions.rs

@@ -13,13 +13,13 @@ use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for explicit bounds checking when casting.
+    /// ### What it does
+    /// Checks for explicit bounds checking when casting.
     ///
-    /// **Why is this bad?** Reduces the readability of statements & is error prone.
+    /// ### Why is this bad?
+    /// Reduces the readability of statements & is error prone.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let foo: u32 = 5;
     /// # let _ =

clippy_lints/src/cognitive_complexity.rs

@@ -14,15 +14,19 @@ use rustc_span::source_map::Span;
 use rustc_span::{sym, BytePos};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for methods with high cognitive complexity.
+    /// ### What it does
+    /// Checks for methods with high cognitive complexity.
     ///
-    /// **Why is this bad?** Methods of high cognitive complexity tend to be hard to
+    /// ### Why is this bad?
+    /// Methods of high cognitive complexity tend to be hard to
     /// both read and maintain. Also LLVM will tend to optimize small methods better.
     ///
-    /// **Known problems:** Sometimes it's hard to find a way to reduce the
+    /// ### Known problems
+    /// Sometimes it's hard to find a way to reduce the
     /// complexity.
     ///
-    /// **Example:** No. You'll see it when you get the warning.
+    /// ### Example
+    /// No. You'll see it when you get the warning.
     pub COGNITIVE_COMPLEXITY,
     nursery,
     "functions that should be split up into multiple functions"

clippy_lints/src/collapsible_if.rs

@@ -22,15 +22,15 @@ use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for nested `if` statements which can be collapsed
+    /// ### What it does
+    /// Checks for nested `if` statements which can be collapsed
     /// by `&&`-combining their conditions.
     ///
-    /// **Why is this bad?** Each `if`-statement adds one level of nesting, which
+    /// ### Why is this bad?
+    /// Each `if`-statement adds one level of nesting, which
     /// makes code look more complex than it really is.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// if x {
     ///     if y {
@@ -53,15 +53,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for collapsible `else { if ... }` expressions
+    /// ### What it does
+    /// Checks for collapsible `else { if ... }` expressions
     /// that can be collapsed to `else if ...`.
     ///
-    /// **Why is this bad?** Each `if`-statement adds one level of nesting, which
+    /// ### Why is this bad?
+    /// Each `if`-statement adds one level of nesting, which
     /// makes code look more complex than it really is.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     ///
     /// if x {

clippy_lints/src/collapsible_match.rs

@@ -9,18 +9,17 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{MultiSpan, Span};
 
 declare_clippy_lint! {
-    /// **What it does:** Finds nested `match` or `if let` expressions where the patterns may be "collapsed" together
+    /// ### What it does
+    /// Finds nested `match` or `if let` expressions where the patterns may be "collapsed" together
     /// without adding any branches.
     ///
     /// Note that this lint is not intended to find _all_ cases where nested match patterns can be merged, but only
     /// cases where merging would most likely make the code more readable.
     ///
-    /// **Why is this bad?** It is unnecessarily verbose and complex.
-    ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// It is unnecessarily verbose and complex.
     ///
+    /// ### Example
     /// ```rust
     /// fn func(opt: Option<Result<u64, String>>) {
     ///     let n = match opt {

clippy_lints/src/comparison_chain.rs

@@ -6,16 +6,19 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks comparison chains written with `if` that can be
+    /// ### What it does
+    /// Checks comparison chains written with `if` that can be
     /// rewritten with `match` and `cmp`.
     ///
-    /// **Why is this bad?** `if` is not guaranteed to be exhaustive and conditionals can get
+    /// ### Why is this bad?
+    /// `if` is not guaranteed to be exhaustive and conditionals can get
     /// repetitive
     ///
-    /// **Known problems:** The match statement may be slower due to the compiler
+    /// ### Known problems
+    /// The match statement may be slower due to the compiler
     /// not inlining the call to cmp. See issue [#5354](https://github.com/rust-lang/rust-clippy/issues/5354)
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// # fn a() {}
     /// # fn b() {}

clippy_lints/src/copies.rs

@@ -16,13 +16,13 @@ use rustc_span::{source_map::Span, symbol::Symbol, BytePos};
 use std::borrow::Cow;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for consecutive `if`s with the same condition.
+    /// ### What it does
+    /// Checks for consecutive `if`s with the same condition.
     ///
-    /// **Why is this bad?** This is probably a copy & paste error.
+    /// ### Why is this bad?
+    /// This is probably a copy & paste error.
     ///
-    /// **Known problems:** Hopefully none.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// if a == b {
     ///     …
@@ -47,15 +47,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for consecutive `if`s with the same function call.
+    /// ### What it does
+    /// Checks for consecutive `if`s with the same function call.
     ///
-    /// **Why is this bad?** This is probably a copy & paste error.
+    /// ### Why is this bad?
+    /// This is probably a copy & paste error.
     /// Despite the fact that function can have side effects and `if` works as
     /// intended, such an approach is implicit and can be considered a "code smell".
     ///
-    /// **Known problems:** Hopefully none.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// if foo() == bar {
     ///     …
@@ -94,14 +94,14 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `if/else` with the same body as the *then* part
+    /// ### What it does
+    /// Checks for `if/else` with the same body as the *then* part
     /// and the *else* part.
     ///
-    /// **Why is this bad?** This is probably a copy & paste error.
+    /// ### Why is this bad?
+    /// This is probably a copy & paste error.
     ///
-    /// **Known problems:** Hopefully none.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// let foo = if … {
     ///     42
@@ -115,17 +115,19 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks if the `if` and `else` block contain shared code that can be
+    /// ### What it does
+    /// Checks if the `if` and `else` block contain shared code that can be
     /// moved out of the blocks.
     ///
-    /// **Why is this bad?** Duplicate code is less maintainable.
+    /// ### Why is this bad?
+    /// Duplicate code is less maintainable.
     ///
-    /// **Known problems:**
+    /// ### Known problems
     /// * The lint doesn't check if the moved expressions modify values that are beeing used in
     ///   the if condition. The suggestion can in that case modify the behavior of the program.
     ///   See [rust-clippy#7452](https://github.com/rust-lang/rust-clippy/issues/7452)
     ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// let foo = if … {
     ///     println!("Hello World");

clippy_lints/src/copy_iterator.rs

@@ -8,15 +8,15 @@ use rustc_span::sym;
 use if_chain::if_chain;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for types that implement `Copy` as well as
+    /// ### What it does
+    /// Checks for types that implement `Copy` as well as
     /// `Iterator`.
     ///
-    /// **Why is this bad?** Implicit copies can be confusing when working with
+    /// ### Why is this bad?
+    /// Implicit copies can be confusing when working with
     /// iterator combinators.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// #[derive(Copy, Clone)]
     /// struct Countdown(u8);

clippy_lints/src/create_dir.rs

@@ -8,13 +8,13 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks usage of `std::fs::create_dir` and suggest using `std::fs::create_dir_all` instead.
+    /// ### What it does
+    /// Checks usage of `std::fs::create_dir` and suggest using `std::fs::create_dir_all` instead.
     ///
-    /// **Why is this bad?** Sometimes `std::fs::create_dir` is mistakenly chosen over `std::fs::create_dir_all`.
+    /// ### Why is this bad?
+    /// Sometimes `std::fs::create_dir` is mistakenly chosen over `std::fs::create_dir_all`.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     ///
     /// ```rust
     /// std::fs::create_dir("foo");

clippy_lints/src/dbg_macro.rs

@@ -8,14 +8,14 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of dbg!() macro.
+    /// ### What it does
+    /// Checks for usage of dbg!() macro.
     ///
-    /// **Why is this bad?** `dbg!` macro is intended as a debugging tool. It
+    /// ### Why is this bad?
+    /// `dbg!` macro is intended as a debugging tool. It
     /// should not be in version control.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// // Bad
     /// dbg!(true)

clippy_lints/src/default.rs

@@ -13,14 +13,14 @@ use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for literal calls to `Default::default()`.
+    /// ### What it does
+    /// Checks for literal calls to `Default::default()`.
     ///
-    /// **Why is this bad?** It's more clear to the reader to use the name of the type whose default is
+    /// ### Why is this bad?
+    /// It's more clear to the reader to use the name of the type whose default is
     /// being gotten than the generic `Default`.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// // Bad
     /// let s: String = Default::default();
@@ -34,14 +34,17 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for immediate reassignment of fields initialized
+    /// ### What it does
+    /// Checks for immediate reassignment of fields initialized
     /// with Default::default().
     ///
-    /// **Why is this bad?**It's more idiomatic to use the [functional update syntax](https://doc.rust-lang.org/reference/expressions/struct-expr.html#functional-update-syntax).
+    /// ### Why is this bad?
+    ///It's more idiomatic to use the [functional update syntax](https://doc.rust-lang.org/reference/expressions/struct-expr.html#functional-update-syntax).
     ///
-    /// **Known problems:** Assignments to patterns that are of tuple type are not linted.
+    /// ### Known problems
+    /// Assignments to patterns that are of tuple type are not linted.
     ///
-    /// **Example:**
+    /// ### Example
     /// Bad:
     /// ```
     /// # #[derive(Default)]

clippy_lints/src/default_numeric_fallback.rs

@@ -18,7 +18,8 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use std::iter;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of unconstrained numeric literals which may cause default numeric fallback in type
+    /// ### What it does
+    /// Checks for usage of unconstrained numeric literals which may cause default numeric fallback in type
     /// inference.
     ///
     /// Default numeric fallback means that if numeric types have not yet been bound to concrete
@@ -27,12 +28,14 @@ declare_clippy_lint! {
     ///
     /// See [RFC0212](https://github.com/rust-lang/rfcs/blob/master/text/0212-restore-int-fallback.md) for more information about the fallback.
     ///
-    /// **Why is this bad?** For those who are very careful about types, default numeric fallback
+    /// ### Why is this bad?
+    /// For those who are very careful about types, default numeric fallback
     /// can be a pitfall that cause unexpected runtime behavior.
     ///
-    /// **Known problems:** This lint can only be allowed at the function level or above.
+    /// ### Known problems
+    /// This lint can only be allowed at the function level or above.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let i = 10;
     /// let f = 1.23;

clippy_lints/src/deprecated_lints.rs

@@ -12,27 +12,33 @@ macro_rules! declare_deprecated_lint {
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This used to check for `assert!(a == b)` and recommend
+    /// ### Deprecation reason
+    /// This used to check for `assert!(a == b)` and recommend
     /// replacement with `assert_eq!(a, b)`, but this is no longer needed after RFC 2011.
     pub SHOULD_ASSERT_EQ,
     "`assert!()` will be more flexible with RFC 2011"
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This used to check for `Vec::extend`, which was slower than
+    /// ### Deprecation reason
+    /// This used to check for `Vec::extend`, which was slower than
     /// `Vec::extend_from_slice`. Thanks to specialization, this is no longer true.
     pub EXTEND_FROM_SLICE,
     "`.extend_from_slice(_)` is a faster way to extend a Vec by a slice"
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** `Range::step_by(0)` used to be linted since it's
+    /// ### Deprecation reason
+    /// `Range::step_by(0)` used to be linted since it's
     /// an infinite iterator, which is better expressed by `iter::repeat`,
     /// but the method has been removed for `Iterator::step_by` which panics
     /// if given a zero
@@ -41,27 +47,33 @@ declare_deprecated_lint! {
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This used to check for `Vec::as_slice`, which was unstable with good
+    /// ### Deprecation reason
+    /// This used to check for `Vec::as_slice`, which was unstable with good
     /// stable alternatives. `Vec::as_slice` has now been stabilized.
     pub UNSTABLE_AS_SLICE,
     "`Vec::as_slice` has been stabilized in 1.7"
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This used to check for `Vec::as_mut_slice`, which was unstable with good
+    /// ### Deprecation reason
+    /// This used to check for `Vec::as_mut_slice`, which was unstable with good
     /// stable alternatives. `Vec::as_mut_slice` has now been stabilized.
     pub UNSTABLE_AS_MUT_SLICE,
     "`Vec::as_mut_slice` has been stabilized in 1.7"
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This lint should never have applied to non-pointer types, as transmuting
+    /// ### Deprecation reason
+    /// This lint should never have applied to non-pointer types, as transmuting
     /// between non-pointer types of differing alignment is well-defined behavior (it's semantically
     /// equivalent to a memcpy). This lint has thus been refactored into two separate lints:
     /// cast_ptr_alignment and transmute_ptr_to_ptr.
@@ -70,9 +82,11 @@ declare_deprecated_lint! {
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This lint is too subjective, not having a good reason for being in clippy.
+    /// ### Deprecation reason
+    /// This lint is too subjective, not having a good reason for being in clippy.
     /// Additionally, compound assignment operators may be overloaded separately from their non-assigning
     /// counterparts, so this lint may suggest a change in behavior or the code may not compile.
     pub ASSIGN_OPS,
@@ -80,9 +94,11 @@ declare_deprecated_lint! {
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** The original rule will only lint for `if let`. After
+    /// ### Deprecation reason
+    /// The original rule will only lint for `if let`. After
     /// making it support to lint `match`, naming as `if let` is not suitable for it.
     /// So, this lint is deprecated.
     pub IF_LET_REDUNDANT_PATTERN_MATCHING,
@@ -90,9 +106,11 @@ declare_deprecated_lint! {
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This lint used to suggest replacing `let mut vec =
+    /// ### Deprecation reason
+    /// This lint used to suggest replacing `let mut vec =
     /// Vec::with_capacity(n); vec.set_len(n);` with `let vec = vec![0; n];`. The
     /// replacement has very different performance characteristics so the lint is
     /// deprecated.
@@ -101,51 +119,63 @@ declare_deprecated_lint! {
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This lint has been superseded by #[must_use] in rustc.
+    /// ### Deprecation reason
+    /// This lint has been superseded by #[must_use] in rustc.
     pub UNUSED_COLLECT,
     "`collect` has been marked as #[must_use] in rustc and that covers all cases of this lint"
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** Associated-constants are now preferred.
+    /// ### Deprecation reason
+    /// Associated-constants are now preferred.
     pub REPLACE_CONSTS,
     "associated-constants `MIN`/`MAX` of integers are preferred to `{min,max}_value()` and module constants"
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** The regex! macro does not exist anymore.
+    /// ### Deprecation reason
+    /// The regex! macro does not exist anymore.
     pub REGEX_MACRO,
     "the regex! macro has been removed from the regex crate in 2018"
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This lint has been replaced by `manual_find_map`, a
+    /// ### Deprecation reason
+    /// This lint has been replaced by `manual_find_map`, a
     /// more specific lint.
     pub FIND_MAP,
     "this lint has been replaced by `manual_find_map`, a more specific lint"
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** This lint has been replaced by `manual_filter_map`, a
+    /// ### Deprecation reason
+    /// This lint has been replaced by `manual_filter_map`, a
     /// more specific lint.
     pub FILTER_MAP,
     "this lint has been replaced by `manual_filter_map`, a more specific lint"
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** The `avoid_breaking_exported_api` config option was added, which
+    /// ### Deprecation reason
+    /// The `avoid_breaking_exported_api` config option was added, which
     /// enables the `enum_variant_names` lint for public items.
     /// ```
     pub PUB_ENUM_VARIANT_NAMES,
@@ -153,9 +183,11 @@ declare_deprecated_lint! {
 }
 
 declare_deprecated_lint! {
-    /// **What it does:** Nothing. This lint has been deprecated.
+    /// ### What it does
+    /// Nothing. This lint has been deprecated.
     ///
-    /// **Deprecation reason:** The `avoid_breaking_exported_api` config option was added, which
+    /// ### Deprecation reason
+    /// The `avoid_breaking_exported_api` config option was added, which
     /// enables the `wrong_self_conversion` lint for public items.
     pub WRONG_PUB_SELF_CONVENTION,
     "set the `avoid-breaking-exported-api` config option to `false` to enable the `wrong_self_convention` lint for public items"

clippy_lints/src/dereference.rs

@@ -11,12 +11,14 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::{symbol::sym, Span};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for explicit `deref()` or `deref_mut()` method calls.
+    /// ### What it does
+    /// Checks for explicit `deref()` or `deref_mut()` method calls.
     ///
-    /// **Why is this bad?** Dereferencing by `&*x` or `&mut *x` is clearer and more concise,
+    /// ### Why is this bad?
+    /// Dereferencing by `&*x` or `&mut *x` is clearer and more concise,
     /// when not part of a method chain.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// use std::ops::Deref;
     /// let a: &mut String = &mut String::from("foo");

clippy_lints/src/derive.rs

@@ -15,10 +15,12 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for deriving `Hash` but implementing `PartialEq`
+    /// ### What it does
+    /// Checks for deriving `Hash` but implementing `PartialEq`
     /// explicitly or vice versa.
     ///
-    /// **Why is this bad?** The implementation of these traits must agree (for
+    /// ### Why is this bad?
+    /// The implementation of these traits must agree (for
     /// example for use with `HashMap`) so it’s probably a bad idea to use a
     /// default-generated `Hash` implementation with an explicitly defined
     /// `PartialEq`. In particular, the following must hold for any type:
@@ -27,9 +29,7 @@ declare_clippy_lint! {
     /// k1 == k2 ⇒ hash(k1) == hash(k2)
     /// ```
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// #[derive(Hash)]
     /// struct Foo;
@@ -44,10 +44,12 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for deriving `Ord` but implementing `PartialOrd`
+    /// ### What it does
+    /// Checks for deriving `Ord` but implementing `PartialOrd`
     /// explicitly or vice versa.
     ///
-    /// **Why is this bad?** The implementation of these traits must agree (for
+    /// ### Why is this bad?
+    /// The implementation of these traits must agree (for
     /// example for use with `sort`) so it’s probably a bad idea to use a
     /// default-generated `Ord` implementation with an explicitly defined
     /// `PartialOrd`. In particular, the following must hold for any type
@@ -57,10 +59,7 @@ declare_clippy_lint! {
     /// k1.cmp(&k2) == k1.partial_cmp(&k2).unwrap()
     /// ```
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust,ignore
     /// #[derive(Ord, PartialEq, Eq)]
     /// struct Foo;
@@ -95,18 +94,21 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for explicit `Clone` implementations for `Copy`
+    /// ### What it does
+    /// Checks for explicit `Clone` implementations for `Copy`
     /// types.
     ///
-    /// **Why is this bad?** To avoid surprising behaviour, these traits should
+    /// ### Why is this bad?
+    /// To avoid surprising behaviour, these traits should
     /// agree and the behaviour of `Copy` cannot be overridden. In almost all
     /// situations a `Copy` type should have a `Clone` implementation that does
     /// nothing more than copy the object, which is what `#[derive(Copy, Clone)]`
     /// gets you.
     ///
-    /// **Known problems:** Bounds of generic types are sometimes wrong: https://github.com/rust-lang/rust/issues/26925
+    /// ### Known problems
+    /// Bounds of generic types are sometimes wrong: https://github.com/rust-lang/rust/issues/26925
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// #[derive(Copy)]
     /// struct Foo;
@@ -121,16 +123,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for deriving `serde::Deserialize` on a type that
+    /// ### What it does
+    /// Checks for deriving `serde::Deserialize` on a type that
     /// has methods using `unsafe`.
     ///
-    /// **Why is this bad?** Deriving `serde::Deserialize` will create a constructor
+    /// ### Why is this bad?
+    /// Deriving `serde::Deserialize` will create a constructor
     /// that may violate invariants hold by another constructor.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust,ignore
     /// use serde::Deserialize;
     ///

clippy_lints/src/disallowed_method.rs

@@ -8,15 +8,14 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::Symbol;
 
 declare_clippy_lint! {
-    /// **What it does:** Denies the configured methods and functions in clippy.toml
+    /// ### What it does
+    /// Denies the configured methods and functions in clippy.toml
     ///
-    /// **Why is this bad?** Some methods are undesirable in certain contexts,
+    /// ### Why is this bad?
+    /// Some methods are undesirable in certain contexts,
     /// and it's beneficial to lint for them as needed.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// An example clippy.toml configuration:
     /// ```toml
     /// # clippy.toml

clippy_lints/src/disallowed_script_idents.rs

@@ -6,7 +6,8 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use unicode_script::{Script, UnicodeScript};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of unicode scripts other than those explicitly allowed
+    /// ### What it does
+    /// Checks for usage of unicode scripts other than those explicitly allowed
     /// by the lint config.
     ///
     /// This lint doesn't take into account non-text scripts such as `Unknown` and `Linear_A`.
@@ -19,7 +20,8 @@ declare_clippy_lint! {
     /// [aliases]: http://www.unicode.org/reports/tr24/tr24-31.html#Script_Value_Aliases
     /// [supported_scripts]: https://www.unicode.org/iso15924/iso15924-codes.html
     ///
-    /// **Why is this bad?** It may be not desired to have many different scripts for
+    /// ### Why is this bad?
+    /// It may be not desired to have many different scripts for
     /// identifiers in the codebase.
     ///
     /// Note that if you only want to allow plain English, you might want to use
@@ -27,9 +29,7 @@ declare_clippy_lint! {
     ///
     /// [`non_ascii_idents`]: https://doc.rust-lang.org/rustc/lints/listing/allowed-by-default.html#non-ascii-idents
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// // Assuming that `clippy.toml` contains the following line:
     /// // allowed-locales = ["Latin", "Cyrillic"]

clippy_lints/src/disallowed_type.rs

@@ -2,27 +2,24 @@ use clippy_utils::diagnostics::span_lint;
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::{
-    def::Res, def_id::DefId, Crate, Item, ItemKind, PolyTraitRef, TraitBoundModifier, Ty, TyKind, UseKind,
+    def::Res, def_id::DefId, Crate, Item, ItemKind, PolyTraitRef, PrimTy, TraitBoundModifier, Ty, TyKind, UseKind,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::{Span, Symbol};
 
 declare_clippy_lint! {
-    /// **What it does:** Denies the configured types in clippy.toml.
+    /// ### What it does
+    /// Denies the configured types in clippy.toml.
     ///
-    /// **Why is this bad?** Some types are undesirable in certain contexts.
-    ///
-    /// **Known problems:** None.
-    ///
-    /// N.B. There is no way to ban primitive types.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// Some types are undesirable in certain contexts.
     ///
+    /// ### Example:
     /// An example clippy.toml configuration:
     /// ```toml
     /// # clippy.toml
-    /// disallowed-methods = ["std::collections::BTreeMap"]
+    /// disallowed-types = ["std::collections::BTreeMap"]
     /// ```
     ///
     /// ```rust,ignore
@@ -42,7 +39,8 @@ declare_clippy_lint! {
 #[derive(Clone, Debug)]
 pub struct DisallowedType {
     disallowed: FxHashSet<Vec<Symbol>>,
-    def_ids: FxHashSet<(DefId, Vec<Symbol>)>,
+    def_ids: FxHashSet<DefId>,
+    prim_tys: FxHashSet<PrimTy>,
 }
 
 impl DisallowedType {
@@ -53,6 +51,23 @@ impl DisallowedType {
                 .map(|s| s.split("::").map(|seg| Symbol::intern(seg)).collect::<Vec<_>>())
                 .collect(),
             def_ids: FxHashSet::default(),
+            prim_tys: FxHashSet::default(),
+        }
+    }
+
+    fn check_res_emit(&self, cx: &LateContext<'_>, res: &Res, span: Span) {
+        match res {
+            Res::Def(_, did) => {
+                if self.def_ids.contains(did) {
+                    emit(cx, &cx.tcx.def_path_str(*did), span);
+                }
+            },
+            Res::PrimTy(prim) => {
+                if self.prim_tys.contains(prim) {
+                    emit(cx, prim.name_str(), span);
+                }
+            },
+            _ => {},
         }
     }
 }
@@ -63,60 +78,36 @@ impl<'tcx> LateLintPass<'tcx> for DisallowedType {
     fn check_crate(&mut self, cx: &LateContext<'_>, _: &Crate<'_>) {
         for path in &self.disallowed {
             let segs = path.iter().map(ToString::to_string).collect::<Vec<_>>();
-            if let Res::Def(_, id) = clippy_utils::path_to_res(cx, &segs.iter().map(String::as_str).collect::<Vec<_>>())
-            {
-                self.def_ids.insert((id, path.clone()));
+            match clippy_utils::path_to_res(cx, &segs.iter().map(String::as_str).collect::<Vec<_>>()) {
+                Res::Def(_, id) => {
+                    self.def_ids.insert(id);
+                },
+                Res::PrimTy(ty) => {
+                    self.prim_tys.insert(ty);
+                },
+                _ => {},
             }
         }
     }
 
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
-        if_chain! {
-            if let ItemKind::Use(path, UseKind::Single) = &item.kind;
-            if let Res::Def(_, did) = path.res;
-            if let Some((_, name)) = self.def_ids.iter().find(|(id, _)| *id == did);
-            then {
-                emit(cx, name, item.span,);
-            }
+        if let ItemKind::Use(path, UseKind::Single) = &item.kind {
+            self.check_res_emit(cx, &path.res, item.span);
         }
     }
 
     fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx Ty<'tcx>) {
-        if_chain! {
-            if let TyKind::Path(path) = &ty.kind;
-            if let Some(did) = cx.qpath_res(path, ty.hir_id).opt_def_id();
-            if let Some((_, name)) = self.def_ids.iter().find(|(id, _)| *id == did);
-            then {
-                emit(cx, name, path.span());
-            }
+        if let TyKind::Path(path) = &ty.kind {
+            self.check_res_emit(cx, &cx.qpath_res(path, ty.hir_id), ty.span);
         }
     }
 
     fn check_poly_trait_ref(&mut self, cx: &LateContext<'tcx>, poly: &'tcx PolyTraitRef<'tcx>, _: TraitBoundModifier) {
-        if_chain! {
-            if let Res::Def(_, did) = poly.trait_ref.path.res;
-            if let Some((_, name)) = self.def_ids.iter().find(|(id, _)| *id == did);
-            then {
-                emit(cx, name, poly.trait_ref.path.span);
-            }
-        }
+        self.check_res_emit(cx, &poly.trait_ref.path.res, poly.trait_ref.path.span);
     }
-
-    // TODO: if non primitive const generics are a thing
-    // fn check_generic_arg(&mut self, cx: &LateContext<'tcx>, arg: &'tcx GenericArg<'tcx>) {
-    //     match arg {
-    //         GenericArg::Const(c) => {},
-    //     }
-    // }
-    // fn check_generic_param(&mut self, cx: &LateContext<'tcx>, param: &'tcx GenericParam<'tcx>) {
-    //     match param.kind {
-    //         GenericParamKind::Const { .. } => {},
-    //     }
-    // }
 }
 
-fn emit(cx: &LateContext<'_>, name: &[Symbol], span: Span) {
-    let name = name.iter().map(|s| s.to_ident_string()).collect::<Vec<_>>().join("::");
+fn emit(cx: &LateContext<'_>, name: &str, span: Span) {
     span_lint(
         cx,
         DISALLOWED_TYPE,

clippy_lints/src/doc.rs

@@ -30,15 +30,18 @@ use std::thread;
 use url::Url;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for the presence of `_`, `::` or camel-case words
+    /// ### What it does
+    /// Checks for the presence of `_`, `::` or camel-case words
     /// outside ticks in documentation.
     ///
-    /// **Why is this bad?** *Rustdoc* supports markdown formatting, `_`, `::` and
+    /// ### Why is this bad?
+    /// *Rustdoc* supports markdown formatting, `_`, `::` and
     /// camel-case probably indicates some code which should be included between
     /// ticks. `_` can also be used for emphasis in markdown, this lint tries to
     /// consider that.
     ///
-    /// **Known problems:** Lots of bad docs won’t be fixed, what the lint checks
+    /// ### Known problems
+    /// Lots of bad docs won’t be fixed, what the lint checks
     /// for is limited, and there are still false positives. HTML elements and their
     /// content are not linted.
     ///
@@ -47,7 +50,7 @@ declare_clippy_lint! {
     /// `[`SmallVec<[T; INLINE_CAPACITY]>`]` and then [`SmallVec<[T; INLINE_CAPACITY]>`]: SmallVec
     /// would fail.
     ///
-    /// **Examples:**
+    /// ### Examples
     /// ```rust
     /// /// Do something with the foo_bar parameter. See also
     /// /// that::other::module::foo.
@@ -68,15 +71,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for the doc comments of publicly visible
+    /// ### What it does
+    /// Checks for the doc comments of publicly visible
     /// unsafe functions and warns if there is no `# Safety` section.
     ///
-    /// **Why is this bad?** Unsafe functions should document their safety
+    /// ### Why is this bad?
+    /// Unsafe functions should document their safety
     /// preconditions, so that users can be sure they are using them safely.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Examples:**
+    /// ### Examples
     /// ```rust
     ///# type Universe = ();
     /// /// This function should really be documented
@@ -102,16 +105,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks the doc comments of publicly visible functions that
+    /// ### What it does
+    /// Checks the doc comments of publicly visible functions that
     /// return a `Result` type and warns if there is no `# Errors` section.
     ///
-    /// **Why is this bad?** Documenting the type of errors that can be returned from a
+    /// ### Why is this bad?
+    /// Documenting the type of errors that can be returned from a
     /// function can help callers write code to handle the errors appropriately.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Examples:**
-    ///
+    /// ### Examples
     /// Since the following function returns a `Result` it has an `# Errors` section in
     /// its doc comment:
     ///
@@ -131,16 +133,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks the doc comments of publicly visible functions that
+    /// ### What it does
+    /// Checks the doc comments of publicly visible functions that
     /// may panic and warns if there is no `# Panics` section.
     ///
-    /// **Why is this bad?** Documenting the scenarios in which panicking occurs
+    /// ### Why is this bad?
+    /// Documenting the scenarios in which panicking occurs
     /// can help callers who do not want to panic to avoid those situations.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Examples:**
-    ///
+    /// ### Examples
     /// Since the following function may panic it has a `# Panics` section in
     /// its doc comment:
     ///
@@ -162,14 +163,14 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `fn main() { .. }` in doctests
+    /// ### What it does
+    /// Checks for `fn main() { .. }` in doctests
     ///
-    /// **Why is this bad?** The test can be shorter (and likely more readable)
+    /// ### Why is this bad?
+    /// The test can be shorter (and likely more readable)
     /// if the `fn main()` is left implicit.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Examples:**
+    /// ### Examples
     /// ``````rust
     /// /// An example of a doctest with a `main()` function
     /// ///

clippy_lints/src/double_comparison.rs

@@ -10,14 +10,14 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for double comparisons that could be simplified to a single expression.
+    /// ### What it does
+    /// Checks for double comparisons that could be simplified to a single expression.
     ///
     ///
-    /// **Why is this bad?** Readability.
+    /// ### Why is this bad?
+    /// Readability.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let x = 1;
     /// # let y = 2;

clippy_lints/src/double_parens.rs

@@ -4,14 +4,14 @@ use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for unnecessary double parentheses.
+    /// ### What it does
+    /// Checks for unnecessary double parentheses.
     ///
-    /// **Why is this bad?** This makes code harder to read and might indicate a
+    /// ### Why is this bad?
+    /// This makes code harder to read and might indicate a
     /// mistake.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// // Bad
     /// fn simple_double_parens() -> i32 {

clippy_lints/src/drop_forget_ref.rs

@@ -8,17 +8,17 @@ use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for calls to `std::mem::drop` with a reference
+    /// ### What it does
+    /// Checks for calls to `std::mem::drop` with a reference
     /// instead of an owned value.
     ///
-    /// **Why is this bad?** Calling `drop` on a reference will only drop the
+    /// ### Why is this bad?
+    /// Calling `drop` on a reference will only drop the
     /// reference itself, which is a no-op. It will not call the `drop` method (from
     /// the `Drop` trait implementation) on the underlying referenced value, which
     /// is likely what was intended.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// let mut lock_guard = mutex.lock();
     /// std::mem::drop(&lock_guard) // Should have been drop(lock_guard), mutex
@@ -31,17 +31,17 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for calls to `std::mem::forget` with a reference
+    /// ### What it does
+    /// Checks for calls to `std::mem::forget` with a reference
     /// instead of an owned value.
     ///
-    /// **Why is this bad?** Calling `forget` on a reference will only forget the
+    /// ### Why is this bad?
+    /// Calling `forget` on a reference will only forget the
     /// reference itself, which is a no-op. It will not forget the underlying
     /// referenced
     /// value, which is likely what was intended.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let x = Box::new(1);
     /// std::mem::forget(&x) // Should have been forget(x), x will still be dropped
@@ -52,16 +52,16 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for calls to `std::mem::drop` with a value
+    /// ### What it does
+    /// Checks for calls to `std::mem::drop` with a value
     /// that derives the Copy trait
     ///
-    /// **Why is this bad?** Calling `std::mem::drop` [does nothing for types that
+    /// ### Why is this bad?
+    /// Calling `std::mem::drop` [does nothing for types that
     /// implement Copy](https://doc.rust-lang.org/std/mem/fn.drop.html), since the
     /// value will be copied and moved into the function on invocation.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let x: i32 = 42; // i32 implements Copy
     /// std::mem::drop(x) // A copy of x is passed to the function, leaving the
@@ -73,10 +73,12 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for calls to `std::mem::forget` with a value that
+    /// ### What it does
+    /// Checks for calls to `std::mem::forget` with a value that
     /// derives the Copy trait
     ///
-    /// **Why is this bad?** Calling `std::mem::forget` [does nothing for types that
+    /// ### Why is this bad?
+    /// Calling `std::mem::forget` [does nothing for types that
     /// implement Copy](https://doc.rust-lang.org/std/mem/fn.drop.html) since the
     /// value will be copied and moved into the function on invocation.
     ///
@@ -86,9 +88,7 @@ declare_clippy_lint! {
     /// there
     /// is nothing for `std::mem::forget` to ignore.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let x: i32 = 42; // i32 implements Copy
     /// std::mem::forget(x) // A copy of x is passed to the function, leaving the

clippy_lints/src/duration_subsec.rs

@@ -12,15 +12,15 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::paths;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for calculation of subsecond microseconds or milliseconds
+    /// ### What it does
+    /// Checks for calculation of subsecond microseconds or milliseconds
     /// from other `Duration` methods.
     ///
-    /// **Why is this bad?** It's more concise to call `Duration::subsec_micros()` or
+    /// ### Why is this bad?
+    /// It's more concise to call `Duration::subsec_micros()` or
     /// `Duration::subsec_millis()` than to calculate them.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # use std::time::Duration;
     /// let dur = Duration::new(5, 0);

clippy_lints/src/else_if_without_else.rs

@@ -7,14 +7,14 @@ use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of if expressions with an `else if` branch,
+    /// ### What it does
+    /// Checks for usage of if expressions with an `else if` branch,
     /// but without a final `else` branch.
     ///
-    /// **Why is this bad?** Some coding guidelines require this (e.g., MISRA-C:2004 Rule 14.10).
+    /// ### Why is this bad?
+    /// Some coding guidelines require this (e.g., MISRA-C:2004 Rule 14.10).
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # fn a() {}
     /// # fn b() {}

clippy_lints/src/empty_enum.rs

@@ -6,13 +6,15 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `enum`s with no variants.
+    /// ### What it does
+    /// Checks for `enum`s with no variants.
     ///
     /// As of this writing, the `never_type` is still a
     /// nightly-only experimental API. Therefore, this lint is only triggered
     /// if the `never_type` is enabled.
     ///
-    /// **Why is this bad?** If you want to introduce a type which
+    /// ### Why is this bad?
+    /// If you want to introduce a type which
     /// can't be instantiated, you should use `!` (the primitive type "never"),
     /// or a wrapper around it, because `!` has more extensive
     /// compiler support (type inference, etc...) and wrappers
@@ -20,10 +22,7 @@ declare_clippy_lint! {
     /// For further information visit [never type documentation](https://doc.rust-lang.org/std/primitive.never.html)
     ///
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// Bad:
     /// ```rust
     /// enum Test {}

clippy_lints/src/entry.rs

@@ -16,12 +16,15 @@ use rustc_span::{Span, SyntaxContext, DUMMY_SP};
 use std::fmt::Write;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for uses of `contains_key` + `insert` on `HashMap`
+    /// ### What it does
+    /// Checks for uses of `contains_key` + `insert` on `HashMap`
     /// or `BTreeMap`.
     ///
-    /// **Why is this bad?** Using `entry` is more efficient.
+    /// ### Why is this bad?
+    /// Using `entry` is more efficient.
     ///
-    /// **Known problems:** The suggestion may have type inference errors in some cases. e.g.
+    /// ### Known problems
+    /// The suggestion may have type inference errors in some cases. e.g.
     /// ```rust
     /// let mut map = std::collections::HashMap::new();
     /// let _ = if !map.contains_key(&0) {
@@ -31,7 +34,7 @@ declare_clippy_lint! {
     /// };
     /// ```
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # use std::collections::HashMap;
     /// # let mut map = HashMap::new();

clippy_lints/src/enum_clike.rs

@@ -11,15 +11,15 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use std::convert::TryFrom;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for C-like enumerations that are
+    /// ### What it does
+    /// Checks for C-like enumerations that are
     /// `repr(isize/usize)` and have values that don't fit into an `i32`.
     ///
-    /// **Why is this bad?** This will truncate the variant value on 32 bit
+    /// ### Why is this bad?
+    /// This will truncate the variant value on 32 bit
     /// architectures, but works fine on 64 bit.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # #[cfg(target_pointer_width = "64")]
     /// #[repr(usize)]

clippy_lints/src/enum_variants.rs

@@ -10,15 +10,15 @@ use rustc_span::source_map::Span;
 use rustc_span::symbol::Symbol;
 
 declare_clippy_lint! {
-    /// **What it does:** Detects enumeration variants that are prefixed or suffixed
+    /// ### What it does
+    /// Detects enumeration variants that are prefixed or suffixed
     /// by the same characters.
     ///
-    /// **Why is this bad?** Enumeration variant names should specify their variant,
+    /// ### Why is this bad?
+    /// Enumeration variant names should specify their variant,
     /// not repeat the enumeration name.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// enum Cake {
     ///     BlackForestCake,
@@ -40,14 +40,14 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Detects type names that are prefixed or suffixed by the
+    /// ### What it does
+    /// Detects type names that are prefixed or suffixed by the
     /// containing module's name.
     ///
-    /// **Why is this bad?** It requires the user to type the module name twice.
+    /// ### Why is this bad?
+    /// It requires the user to type the module name twice.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// mod cake {
     ///     struct BlackForestCake;
@@ -65,10 +65,12 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for modules that have the same name as their
+    /// ### What it does
+    /// Checks for modules that have the same name as their
     /// parent module
     ///
-    /// **Why is this bad?** A typical beginner mistake is to have `mod foo;` and
+    /// ### Why is this bad?
+    /// A typical beginner mistake is to have `mod foo;` and
     /// again `mod foo { ..
     /// }` in `foo.rs`.
     /// The expectation is that items inside the inner `mod foo { .. }` are then
@@ -78,9 +80,7 @@ declare_clippy_lint! {
     /// If this is done on purpose, it would be better to choose a more
     /// representative module name.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// // lib.rs
     /// mod foo;

clippy_lints/src/eq_op.rs

@@ -9,18 +9,21 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for equal operands to comparison, logical and
+    /// ### What it does
+    /// Checks for equal operands to comparison, logical and
     /// bitwise, difference and division binary operators (`==`, `>`, etc., `&&`,
     /// `||`, `&`, `|`, `^`, `-` and `/`).
     ///
-    /// **Why is this bad?** This is usually just a typo or a copy and paste error.
+    /// ### Why is this bad?
+    /// This is usually just a typo or a copy and paste error.
     ///
-    /// **Known problems:** False negatives: We had some false positives regarding
+    /// ### Known problems
+    /// False negatives: We had some false positives regarding
     /// calls (notably [racer](https://github.com/phildawes/racer) had one instance
     /// of `x.pop() && x.pop()`), so we removed matching any function or method
     /// calls. We may introduce a list of known pure functions in the future.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let x = 1;
     /// if x + 1 == x + 1 {}
@@ -37,15 +40,18 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for arguments to `==` which have their address
+    /// ### What it does
+    /// Checks for arguments to `==` which have their address
     /// taken to satisfy a bound
     /// and suggests to dereference the other argument instead
     ///
-    /// **Why is this bad?** It is more idiomatic to dereference the other argument.
+    /// ### Why is this bad?
+    /// It is more idiomatic to dereference the other argument.
     ///
-    /// **Known problems:** None
+    /// ### Known problems
+    /// None
     ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// // Bad
     /// &x == y

clippy_lints/src/erasing_op.rs

@@ -6,15 +6,15 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for erasing operations, e.g., `x * 0`.
+    /// ### What it does
+    /// Checks for erasing operations, e.g., `x * 0`.
     ///
-    /// **Why is this bad?** The whole expression can be replaced by zero.
+    /// ### Why is this bad?
+    /// The whole expression can be replaced by zero.
     /// This is most likely not the intended outcome and should probably be
     /// corrected
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let x = 1;
     /// 0 / x;

clippy_lints/src/escape.rs

@@ -19,16 +19,16 @@ pub struct BoxedLocal {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of `Box<T>` where an unboxed `T` would
+    /// ### What it does
+    /// Checks for usage of `Box<T>` where an unboxed `T` would
     /// work fine.
     ///
-    /// **Why is this bad?** This is an unnecessary allocation, and bad for
+    /// ### Why is this bad?
+    /// This is an unnecessary allocation, and bad for
     /// performance. It is only necessary to allocate if you wish to move the box
     /// into something.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # fn foo(bar: usize) {}
     /// // Bad

clippy_lints/src/eta_reduction.rs

@@ -14,19 +14,22 @@ use rustc_middle::ty::{self, ClosureKind, Ty};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for closures which just call another function where
+    /// ### What it does
+    /// Checks for closures which just call another function where
     /// the function can be called directly. `unsafe` functions or calls where types
     /// get adjusted are ignored.
     ///
-    /// **Why is this bad?** Needlessly creating a closure adds code for no benefit
+    /// ### Why is this bad?
+    /// Needlessly creating a closure adds code for no benefit
     /// and gives the optimizer more work.
     ///
-    /// **Known problems:** If creating the closure inside the closure has a side-
+    /// ### Known problems
+    /// If creating the closure inside the closure has a side-
     /// effect then moving the closure creation out will change when that side-
     /// effect runs.
     /// See [#1439](https://github.com/rust-lang/rust-clippy/issues/1439) for more details.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// // Bad
     /// xs.map(|x| foo(x))
@@ -42,17 +45,20 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for closures which only invoke a method on the closure
+    /// ### What it does
+    /// Checks for closures which only invoke a method on the closure
     /// argument and can be replaced by referencing the method directly.
     ///
-    /// **Why is this bad?** It's unnecessary to create the closure.
+    /// ### Why is this bad?
+    /// It's unnecessary to create the closure.
     ///
-    /// **Known problems:** [#3071](https://github.com/rust-lang/rust-clippy/issues/3071),
+    /// ### Known problems
+    /// [#3071](https://github.com/rust-lang/rust-clippy/issues/3071),
     /// [#3942](https://github.com/rust-lang/rust-clippy/issues/3942),
     /// [#4002](https://github.com/rust-lang/rust-clippy/issues/4002)
     ///
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// Some('a').map(|s| s.to_uppercase());
     /// ```

clippy_lints/src/eval_order_dependence.rs

@@ -9,17 +9,20 @@ use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for a read and a write to the same variable where
+    /// ### What it does
+    /// Checks for a read and a write to the same variable where
     /// whether the read occurs before or after the write depends on the evaluation
     /// order of sub-expressions.
     ///
-    /// **Why is this bad?** It is often confusing to read. In addition, the
+    /// ### Why is this bad?
+    /// It is often confusing to read. In addition, the
     /// sub-expression evaluation order for Rust is not well documented.
     ///
-    /// **Known problems:** Code which intentionally depends on the evaluation
+    /// ### Known problems
+    /// Code which intentionally depends on the evaluation
     /// order, or which is correct for any evaluation order.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let mut x = 0;
     ///
@@ -43,16 +46,19 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for diverging calls that are not match arms or
+    /// ### What it does
+    /// Checks for diverging calls that are not match arms or
     /// statements.
     ///
-    /// **Why is this bad?** It is often confusing to read. In addition, the
+    /// ### Why is this bad?
+    /// It is often confusing to read. In addition, the
     /// sub-expression evaluation order for Rust is not well documented.
     ///
-    /// **Known problems:** Someone might want to use `some_bool || panic!()` as a
+    /// ### Known problems
+    /// Someone might want to use `some_bool || panic!()` as a
     /// shorthand.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,no_run
     /// # fn b() -> bool { true }
     /// # fn c() -> bool { true }

clippy_lints/src/excessive_bools.rs

@@ -8,19 +8,19 @@ use rustc_span::{sym, Span};
 use std::convert::TryInto;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for excessive
+    /// ### What it does
+    /// Checks for excessive
     /// use of bools in structs.
     ///
-    /// **Why is this bad?** Excessive bools in a struct
+    /// ### Why is this bad?
+    /// Excessive bools in a struct
     /// is often a sign that it's used as a state machine,
     /// which is much better implemented as an enum.
     /// If it's not the case, excessive bools usually benefit
     /// from refactoring into two-variant enums for better
     /// readability and API.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// Bad:
     /// ```rust
     /// struct S {
@@ -44,19 +44,19 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for excessive use of
+    /// ### What it does
+    /// Checks for excessive use of
     /// bools in function definitions.
     ///
-    /// **Why is this bad?** Calls to such functions
+    /// ### Why is this bad?
+    /// Calls to such functions
     /// are confusing and error prone, because it's
     /// hard to remember argument order and you have
     /// no type system support to back you up. Using
     /// two-variant enums instead of bools often makes
     /// API easier to use.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// Bad:
     /// ```rust,ignore
     /// fn f(is_round: bool, is_hot: bool) { ... }

clippy_lints/src/exhaustive_items.rs

@@ -8,16 +8,15 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Warns on any exported `enum`s that are not tagged `#[non_exhaustive]`
+    /// ### What it does
+    /// Warns on any exported `enum`s that are not tagged `#[non_exhaustive]`
     ///
-    /// **Why is this bad?** Exhaustive enums are typically fine, but a project which does
+    /// ### Why is this bad?
+    /// Exhaustive enums are typically fine, but a project which does
     /// not wish to make a stability commitment around exported enums may wish to
     /// disable them by default.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// enum Foo {
     ///     Bar,
@@ -38,16 +37,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Warns on any exported `structs`s that are not tagged `#[non_exhaustive]`
+    /// ### What it does
+    /// Warns on any exported `structs`s that are not tagged `#[non_exhaustive]`
     ///
-    /// **Why is this bad?** Exhaustive structs are typically fine, but a project which does
+    /// ### Why is this bad?
+    /// Exhaustive structs are typically fine, but a project which does
     /// not wish to make a stability commitment around exported structs may wish to
     /// disable them by default.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// struct Foo {
     ///     bar: u8,

clippy_lints/src/exit.rs

@@ -6,15 +6,15 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** `exit()`  terminates the program and doesn't provide a
+    /// ### What it does
+    /// `exit()`  terminates the program and doesn't provide a
     /// stack trace.
     ///
-    /// **Why is this bad?** Ideally a program is terminated by finishing
+    /// ### Why is this bad?
+    /// Ideally a program is terminated by finishing
     /// the main function.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// std::process::exit(0)
     /// ```

clippy_lints/src/explicit_write.rs

@@ -9,14 +9,14 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of `write!()` / `writeln()!` which can be
+    /// ### What it does
+    /// Checks for usage of `write!()` / `writeln()!` which can be
     /// replaced with `(e)print!()` / `(e)println!()`
     ///
-    /// **Why is this bad?** Using `(e)println! is clearer and more concise
+    /// ### Why is this bad?
+    /// Using `(e)println! is clearer and more concise
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # use std::io::Write;
     /// # let bar = "furchtbar";

clippy_lints/src/fallible_impl_from.rs

@@ -10,13 +10,13 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{sym, Span};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for impls of `From<..>` that contain `panic!()` or `unwrap()`
+    /// ### What it does
+    /// Checks for impls of `From<..>` that contain `panic!()` or `unwrap()`
     ///
-    /// **Why is this bad?** `TryFrom` should be used if there's a possibility of failure.
+    /// ### Why is this bad?
+    /// `TryFrom` should be used if there's a possibility of failure.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// struct Foo(i32);
     ///

clippy_lints/src/float_equality_without_abs.rs

@@ -11,30 +11,32 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Spanned;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for statements of the form `(a - b) < f32::EPSILON` or
-     /// `(a - b) < f64::EPSILON`. Notes the missing `.abs()`.
-     ///
-     /// **Why is this bad?** The code without `.abs()` is more likely to have a bug.
-     ///
-     /// **Known problems:** If the user can ensure that b is larger than a, the `.abs()` is
-     /// technically unneccessary. However, it will make the code more robust and doesn't have any
-     /// large performance implications. If the abs call was deliberately left out for performance
-     /// reasons, it is probably better to state this explicitly in the code, which then can be done
-     /// with an allow.
-     ///
-     /// **Example:**
-     ///
-     /// ```rust
-     /// pub fn is_roughly_equal(a: f32, b: f32) -> bool {
-     ///     (a - b) < f32::EPSILON
-     /// }
-     /// ```
-     /// Use instead:
-     /// ```rust
-     /// pub fn is_roughly_equal(a: f32, b: f32) -> bool {
-     ///     (a - b).abs() < f32::EPSILON
-     /// }
-     /// ```
+    /// ### What it does
+    /// Checks for statements of the form `(a - b) < f32::EPSILON` or
+    /// `(a - b) < f64::EPSILON`. Notes the missing `.abs()`.
+    ///
+    /// ### Why is this bad?
+    /// The code without `.abs()` is more likely to have a bug.
+    ///
+    /// ### Known problems
+    /// If the user can ensure that b is larger than a, the `.abs()` is
+    /// technically unneccessary. However, it will make the code more robust and doesn't have any
+    /// large performance implications. If the abs call was deliberately left out for performance
+    /// reasons, it is probably better to state this explicitly in the code, which then can be done
+    /// with an allow.
+    ///
+    /// ### Example
+    /// ```rust
+    /// pub fn is_roughly_equal(a: f32, b: f32) -> bool {
+    ///     (a - b) < f32::EPSILON
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// pub fn is_roughly_equal(a: f32, b: f32) -> bool {
+    ///     (a - b).abs() < f32::EPSILON
+    /// }
+    /// ```
     pub FLOAT_EQUALITY_WITHOUT_ABS,
     suspicious,
     "float equality check without `.abs()`"

clippy_lints/src/float_literal.rs

@@ -10,15 +10,14 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use std::fmt;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for float literals with a precision greater
+    /// ### What it does
+    /// Checks for float literals with a precision greater
     /// than that supported by the underlying type.
     ///
-    /// **Why is this bad?** Rust will truncate the literal silently.
-    ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// Rust will truncate the literal silently.
     ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// let v: f32 = 0.123_456_789_9;
@@ -34,16 +33,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for whole number float literals that
+    /// ### What it does
+    /// Checks for whole number float literals that
     /// cannot be represented as the underlying type without loss.
     ///
-    /// **Why is this bad?** Rust will silently lose precision during
+    /// ### Why is this bad?
+    /// Rust will silently lose precision during
     /// conversion to a float.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// let _: f32 = 16_777_217.0; // 16_777_216.0

clippy_lints/src/floating_point_arithmetic.rs

@@ -18,16 +18,15 @@ use std::f64::consts as f64_consts;
 use sugg::Sugg;
 
 declare_clippy_lint! {
-    /// **What it does:** Looks for floating-point expressions that
+    /// ### What it does
+    /// Looks for floating-point expressions that
     /// can be expressed using built-in methods to improve accuracy
     /// at the cost of performance.
     ///
-    /// **Why is this bad?** Negatively impacts accuracy.
-    ///
-    /// **Known problems:** None
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// Negatively impacts accuracy.
     ///
+    /// ### Example
     /// ```rust
     /// let a = 3f32;
     /// let _ = a.powf(1.0 / 3.0);
@@ -49,16 +48,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Looks for floating-point expressions that
+    /// ### What it does
+    /// Looks for floating-point expressions that
     /// can be expressed using built-in methods to improve both
     /// accuracy and performance.
     ///
-    /// **Why is this bad?** Negatively impacts accuracy and performance.
-    ///
-    /// **Known problems:** None
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// Negatively impacts accuracy and performance.
     ///
+    /// ### Example
     /// ```rust
     /// use std::f32::consts::E;
     ///

clippy_lints/src/format.rs

@@ -13,18 +13,18 @@ use rustc_span::symbol::kw;
 use rustc_span::{sym, Span};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for the use of `format!("string literal with no
+    /// ### What it does
+    /// Checks for the use of `format!("string literal with no
     /// argument")` and `format!("{}", foo)` where `foo` is a string.
     ///
-    /// **Why is this bad?** There is no point of doing that. `format!("foo")` can
+    /// ### Why is this bad?
+    /// There is no point of doing that. `format!("foo")` can
     /// be replaced by `"foo".to_owned()` if you really need a `String`. The even
     /// worse `&format!("foo")` is often encountered in the wild. `format!("{}",
     /// foo)` can be replaced by `foo.clone()` if `foo: String` or `foo.to_owned()`
     /// if `foo: &str`.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Examples:**
+    /// ### Examples
     /// ```rust
     ///
     /// // Bad

clippy_lints/src/formatting.rs

@@ -9,15 +9,15 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for use of the non-existent `=*`, `=!` and `=-`
+    /// ### What it does
+    /// Checks for use of the non-existent `=*`, `=!` and `=-`
     /// operators.
     ///
-    /// **Why is this bad?** This is either a typo of `*=`, `!=` or `-=` or
+    /// ### Why is this bad?
+    /// This is either a typo of `*=`, `!=` or `-=` or
     /// confusing.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// a =- 42; // confusing, should it be `a -= 42` or `a = -42`?
     /// ```
@@ -27,15 +27,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks the formatting of a unary operator on the right hand side
+    /// ### What it does
+    /// Checks the formatting of a unary operator on the right hand side
     /// of a binary operator. It lints if there is no space between the binary and unary operators,
     /// but there is a space between the unary and its operand.
     ///
-    /// **Why is this bad?** This is either a typo in the binary operator or confusing.
+    /// ### Why is this bad?
+    /// This is either a typo in the binary operator or confusing.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// if foo <- 30 { // this should be `foo < -30` but looks like a different operator
     /// }
@@ -49,15 +49,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for formatting of `else`. It lints if the `else`
+    /// ### What it does
+    /// Checks for formatting of `else`. It lints if the `else`
     /// is followed immediately by a newline or the `else` seems to be missing.
     ///
-    /// **Why is this bad?** This is probably some refactoring remnant, even if the
+    /// ### Why is this bad?
+    /// This is probably some refactoring remnant, even if the
     /// code is correct, it might look confusing.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// if foo {
     /// } { // looks like an `else` is missing here
@@ -85,14 +85,14 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for possible missing comma in an array. It lints if
+    /// ### What it does
+    /// Checks for possible missing comma in an array. It lints if
     /// an array element is a binary operator expression and it lies on two lines.
     ///
-    /// **Why is this bad?** This could lead to unexpected results.
+    /// ### Why is this bad?
+    /// This could lead to unexpected results.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// let a = &[
     ///     -1, -2, -3 // <= no comma here

clippy_lints/src/from_over_into.rs

@@ -1,21 +1,20 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::paths::INTO;
-use clippy_utils::{match_def_path, meets_msrv, msrvs};
+use clippy_utils::{meets_msrv, msrvs};
 use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::symbol::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Searches for implementations of the `Into<..>` trait and suggests to implement `From<..>` instead.
+    /// ### What it does
+    /// Searches for implementations of the `Into<..>` trait and suggests to implement `From<..>` instead.
     ///
-    /// **Why is this bad?** According the std docs implementing `From<..>` is preferred since it gives you `Into<..>` for free where the reverse isn't true.
-    ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// According the std docs implementing `From<..>` is preferred since it gives you `Into<..>` for free where the reverse isn't true.
     ///
+    /// ### Example
     /// ```rust
     /// struct StringWrapper(String);
     ///
@@ -62,7 +61,7 @@ impl LateLintPass<'_> for FromOverInto {
         if_chain! {
             if let hir::ItemKind::Impl{ .. } = &item.kind;
             if let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(item.def_id);
-            if match_def_path(cx, impl_trait_ref.def_id, &INTO);
+            if cx.tcx.is_diagnostic_item(sym::into_trait, impl_trait_ref.def_id);
 
             then {
                 span_lint_and_help(

clippy_lints/src/from_str_radix_10.rs

@@ -10,20 +10,22 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::sym;
 
 declare_clippy_lint! {
-    /// **What it does:**
+    /// ### What it does
+    ///
     /// Checks for function invocations of the form `primitive::from_str_radix(s, 10)`
     ///
-    /// **Why is this bad?**
+    /// ### Why is this bad?
+    ///
     /// This specific common use case can be rewritten as `s.parse::<primitive>()`
     /// (and in most cases, the turbofish can be removed), which reduces code length
     /// and complexity.
     ///
-    /// **Known problems:**
+    /// ### Known problems
+    ///
     /// This lint may suggest using (&<expression>).parse() instead of <expression>.parse() directly
     /// in some cases, which is correct but adds unnecessary complexity to the code.
     ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```ignore
     /// let input: &str = get_input();
     /// let num = u16::from_str_radix(input, 10)?;

clippy_lints/src/functions/mod.rs

@@ -11,15 +11,15 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for functions with too many parameters.
+    /// ### What it does
+    /// Checks for functions with too many parameters.
     ///
-    /// **Why is this bad?** Functions with lots of parameters are considered bad
+    /// ### Why is this bad?
+    /// Functions with lots of parameters are considered bad
     /// style and reduce readability (“what does the 5th parameter mean?”). Consider
     /// grouping some parameters into a new type.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # struct Color;
     /// fn foo(x: u32, y: u32, name: &str, c: Color, w: f32, h: f32, a: f32, b: f32) {
@@ -32,16 +32,16 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for functions with a large amount of lines.
+    /// ### What it does
+    /// Checks for functions with a large amount of lines.
     ///
-    /// **Why is this bad?** Functions with a lot of lines are harder to understand
+    /// ### Why is this bad?
+    /// Functions with a lot of lines are harder to understand
     /// due to having to look at a larger amount of code to understand what the
     /// function is doing. Consider splitting the body of the function into
     /// multiple functions.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// fn im_too_long() {
     ///     println!("");
@@ -55,15 +55,16 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for public functions that dereference raw pointer
+    /// ### What it does
+    /// Checks for public functions that dereference raw pointer
     /// arguments but are not marked `unsafe`.
     ///
-    /// **Why is this bad?** The function should probably be marked `unsafe`, since
+    /// ### Why is this bad?
+    /// The function should probably be marked `unsafe`, since
     /// for an arbitrary raw pointer, there is no way of telling for sure if it is
     /// valid.
     ///
-    /// **Known problems:**
-    ///
+    /// ### Known problems
     /// * It does not check functions recursively so if the pointer is passed to a
     /// private non-`unsafe` function which does the dereferencing, the lint won't
     /// trigger.
@@ -71,7 +72,7 @@ declare_clippy_lint! {
     /// got from an argument in some other way (`fn foo(bar: &[*const u8])` or
     /// `some_argument.get_raw_ptr()`).
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// // Bad
     /// pub fn foo(x: *const u8) {
@@ -89,17 +90,17 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for a [`#[must_use]`] attribute on
+    /// ### What it does
+    /// Checks for a [`#[must_use]`] attribute on
     /// unit-returning functions and methods.
     ///
     /// [`#[must_use]`]: https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-must_use-attribute
     ///
-    /// **Why is this bad?** Unit values are useless. The attribute is likely
+    /// ### Why is this bad?
+    /// Unit values are useless. The attribute is likely
     /// a remnant of a refactoring that removed the return type.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Examples:**
+    /// ### Examples
     /// ```rust
     /// #[must_use]
     /// fn useless() { }
@@ -110,19 +111,19 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for a [`#[must_use]`] attribute without
+    /// ### What it does
+    /// Checks for a [`#[must_use]`] attribute without
     /// further information on functions and methods that return a type already
     /// marked as `#[must_use]`.
     ///
     /// [`#[must_use]`]: https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-must_use-attribute
     ///
-    /// **Why is this bad?** The attribute isn't needed. Not using the result
+    /// ### Why is this bad?
+    /// The attribute isn't needed. Not using the result
     /// will already be reported. Alternatively, one can add some text to the
     /// attribute to improve the lint message.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Examples:**
+    /// ### Examples
     /// ```rust
     /// #[must_use]
     /// fn double_must_use() -> Result<(), ()> {
@@ -135,16 +136,19 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for public functions that have no
+    /// ### What it does
+    /// Checks for public functions that have no
     /// [`#[must_use]`] attribute, but return something not already marked
     /// must-use, have no mutable arg and mutate no statics.
     ///
     /// [`#[must_use]`]: https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-must_use-attribute
     ///
-    /// **Why is this bad?** Not bad at all, this lint just shows places where
+    /// ### Why is this bad?
+    /// Not bad at all, this lint just shows places where
     /// you could add the attribute.
     ///
-    /// **Known problems:** The lint only checks the arguments for mutable
+    /// ### Known problems
+    /// The lint only checks the arguments for mutable
     /// types without looking if they are actually changed. On the other hand,
     /// it also ignores a broad range of potentially interesting side effects,
     /// because we cannot decide whether the programmer intends the function to
@@ -152,7 +156,7 @@ declare_clippy_lint! {
     /// positives. At least we don't lint if the result type is unit or already
     /// `#[must_use]`.
     ///
-    /// **Examples:**
+    /// ### Examples
     /// ```rust
     /// // this could be annotated with `#[must_use]`.
     /// fn id<T>(t: T) -> T { t }
@@ -163,20 +167,23 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for public functions that return a `Result`
+    /// ### What it does
+    /// Checks for public functions that return a `Result`
     /// with an `Err` type of `()`. It suggests using a custom type that
     /// implements `std::error::Error`.
     ///
-    /// **Why is this bad?** Unit does not implement `Error` and carries no
+    /// ### Why is this bad?
+    /// Unit does not implement `Error` and carries no
     /// further information about what went wrong.
     ///
-    /// **Known problems:** Of course, this lint assumes that `Result` is used
+    /// ### Known problems
+    /// Of course, this lint assumes that `Result` is used
     /// for a fallible operation (which is after all the intended use). However
     /// code may opt to (mis)use it as a basic two-variant-enum. In that case,
     /// the suggestion is misguided, and the code should use a custom enum
     /// instead.
     ///
-    /// **Examples:**
+    /// ### Examples
     /// ```rust
     /// pub fn read_u8() -> Result<u8, ()> { Err(()) }
     /// ```

clippy_lints/src/future_not_send.rs

@@ -12,12 +12,14 @@ use rustc_trait_selection::traits::error_reporting::suggestions::InferCtxtExt;
 use rustc_trait_selection::traits::{self, FulfillmentError, TraitEngine};
 
 declare_clippy_lint! {
-    /// **What it does:** This lint requires Future implementations returned from
+    /// ### What it does
+    /// This lint requires Future implementations returned from
     /// functions and methods to implement the `Send` marker trait. It is mostly
     /// used by library authors (public and internal) that target an audience where
     /// multithreaded executors are likely to be used for running these Futures.
     ///
-    /// **Why is this bad?** A Future implementation captures some state that it
+    /// ### Why is this bad?
+    /// A Future implementation captures some state that it
     /// needs to eventually produce its final value. When targeting a multithreaded
     /// executor (which is the norm on non-embedded devices) this means that this
     /// state may need to be transported to other threads, in other words the
@@ -31,10 +33,7 @@ declare_clippy_lint! {
     /// modifying the library where the offending Future implementation is
     /// produced.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// async fn not_send(bytes: std::rc::Rc<[u8]>) {}
     /// ```

clippy_lints/src/get_last_with_len.rs

@@ -14,10 +14,12 @@ use rustc_span::source_map::Spanned;
 use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for using `x.get(x.len() - 1)` instead of
+    /// ### What it does
+    /// Checks for using `x.get(x.len() - 1)` instead of
     /// `x.last()`.
     ///
-    /// **Why is this bad?** Using `x.last()` is easier to read and has the same
+    /// ### Why is this bad?
+    /// Using `x.last()` is easier to read and has the same
     /// result.
     ///
     /// Note that using `x[x.len() - 1]` is semantically different from
@@ -27,10 +29,7 @@ declare_clippy_lint! {
     /// There is another lint (get_unwrap) that covers the case of using
     /// `x.get(index).unwrap()` instead of `x[index]`.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// let x = vec![2, 3, 5];

clippy_lints/src/identity_op.rs

@@ -11,14 +11,14 @@ use clippy_utils::diagnostics::span_lint;
 use clippy_utils::{clip, unsext};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for identity operations, e.g., `x + 0`.
+    /// ### What it does
+    /// Checks for identity operations, e.g., `x + 0`.
     ///
-    /// **Why is this bad?** This code can be removed without changing the
+    /// ### Why is this bad?
+    /// This code can be removed without changing the
     /// meaning. So it just obscures what's going on. Delete it mercilessly.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let x = 1;
     /// x / 1 + 0 * 1 - 0 | 0;

clippy_lints/src/if_let_mutex.rs

@@ -9,16 +9,15 @@ use rustc_middle::hir::map::Map;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `Mutex::lock` calls in `if let` expression
+    /// ### What it does
+    /// Checks for `Mutex::lock` calls in `if let` expression
     /// with lock calls in any of the else blocks.
     ///
-    /// **Why is this bad?** The Mutex lock remains held for the whole
+    /// ### Why is this bad?
+    /// The Mutex lock remains held for the whole
     /// `if let ... else` block and deadlocks.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust,ignore
     /// if let Ok(thing) = mutex.lock() {
     ///     do_thing();

clippy_lints/src/if_let_some_result.rs

@@ -10,14 +10,14 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:*** Checks for unnecessary `ok()` in if let.
+    /// ### What it does
+    ///* Checks for unnecessary `ok()` in if let.
     ///
-    /// **Why is this bad?** Calling `ok()` in if let is unnecessary, instead match
+    /// ### Why is this bad?
+    /// Calling `ok()` in if let is unnecessary, instead match
     /// on `Ok(pat)`
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// for i in iter {
     ///     if let Some(value) = i.parse().ok() {

clippy_lints/src/if_not_else.rs

@@ -8,14 +8,14 @@ use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of `!` or `!=` in an if condition with an
+    /// ### What it does
+    /// Checks for usage of `!` or `!=` in an if condition with an
     /// else branch.
     ///
-    /// **Why is this bad?** Negations reduce the readability of statements.
+    /// ### Why is this bad?
+    /// Negations reduce the readability of statements.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let v: Vec<usize> = vec![];
     /// # fn a() {}

clippy_lints/src/if_then_some_else_none.rs

@@ -10,14 +10,13 @@ use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for if-else that could be written to `bool::then`.
+    /// ### What it does
+    /// Checks for if-else that could be written to `bool::then`.
     ///
-    /// **Why is this bad?** Looks a little redundant. Using `bool::then` helps it have less lines of code.
-    ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// Looks a little redundant. Using `bool::then` helps it have less lines of code.
     ///
+    /// ### Example
     /// ```rust
     /// # let v = vec![0];
     /// let a = if v.is_empty() {

clippy_lints/src/implicit_hasher.rs

@@ -5,7 +5,7 @@ use std::collections::BTreeMap;
 
 use rustc_errors::DiagnosticBuilder;
 use rustc_hir as hir;
-use rustc_hir::intravisit::{walk_body, walk_expr, walk_ty, walk_inf, NestedVisitorMap, Visitor};
+use rustc_hir::intravisit::{walk_body, walk_expr, walk_inf, walk_ty, NestedVisitorMap, Visitor};
 use rustc_hir::{Body, Expr, ExprKind, GenericArg, Item, ItemKind, QPath, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::map::Map;
@@ -19,24 +19,26 @@ use rustc_typeck::hir_ty_to_ty;
 use if_chain::if_chain;
 
 use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_then};
-use clippy_utils::paths;
+use clippy_utils::differing_macro_contexts;
 use clippy_utils::source::{snippet, snippet_opt};
 use clippy_utils::ty::is_type_diagnostic_item;
-use clippy_utils::{differing_macro_contexts, match_def_path};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for public `impl` or `fn` missing generalization
+    /// ### What it does
+    /// Checks for public `impl` or `fn` missing generalization
     /// over different hashers and implicitly defaulting to the default hashing
     /// algorithm (`SipHash`).
     ///
-    /// **Why is this bad?** `HashMap` or `HashSet` with custom hashers cannot be
+    /// ### Why is this bad?
+    /// `HashMap` or `HashSet` with custom hashers cannot be
     /// used with them.
     ///
-    /// **Known problems:** Suggestions for replacing constructors can contain
+    /// ### Known problems
+    /// Suggestions for replacing constructors can contain
     /// false-positives. Also applying suggestions can require modification of other
     /// pieces of code, possibly including external crates.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # use std::collections::HashMap;
     /// # use std::hash::{Hash, BuildHasher};
@@ -347,7 +349,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for ImplicitHasherConstructorVisitor<'a, 'b, 't
                     return;
                 }
 
-                if match_def_path(self.cx, ty_did, &paths::HASHMAP) {
+                if self.cx.tcx.is_diagnostic_item(sym::hashmap_type, ty_did) {
                     if method.ident.name == sym::new {
                         self.suggestions
                             .insert(e.span, "HashMap::default()".to_string());
@@ -360,7 +362,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for ImplicitHasherConstructorVisitor<'a, 'b, 't
                             ),
                         );
                     }
-                } else if match_def_path(self.cx, ty_did, &paths::HASHSET) {
+                } else if self.cx.tcx.is_diagnostic_item(sym::hashset_type, ty_did) {
                     if method.ident.name == sym::new {
                         self.suggestions
                             .insert(e.span, "HashSet::default()".to_string());

clippy_lints/src/implicit_return.rs

@@ -13,17 +13,17 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{Span, SyntaxContext};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for missing return statements at the end of a block.
+    /// ### What it does
+    /// Checks for missing return statements at the end of a block.
     ///
-    /// **Why is this bad?** Actually omitting the return keyword is idiomatic Rust code. Programmers
+    /// ### Why is this bad?
+    /// Actually omitting the return keyword is idiomatic Rust code. Programmers
     /// coming from other languages might prefer the expressiveness of `return`. It's possible to miss
     /// the last returning statement because the only difference is a missing `;`. Especially in bigger
     /// code with multiple return paths having a `return` keyword makes it easier to find the
     /// corresponding statements.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// fn foo(x: usize) -> usize {
     ///     x

clippy_lints/src/implicit_saturating_sub.rs

@@ -8,14 +8,13 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for implicit saturating subtraction.
+    /// ### What it does
+    /// Checks for implicit saturating subtraction.
     ///
-    /// **Why is this bad?** Simplicity and readability. Instead we can easily use an builtin function.
-    ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// Simplicity and readability. Instead we can easily use an builtin function.
     ///
+    /// ### Example
     /// ```rust
     /// let end: u32 = 10;
     /// let start: u32 = 5;

clippy_lints/src/inconsistent_struct_constructor.rs

@@ -10,11 +10,13 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::Symbol;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for struct constructors where all fields are shorthand and
+    /// ### What it does
+    /// Checks for struct constructors where all fields are shorthand and
     /// the order of the field init shorthand in the constructor is inconsistent
     /// with the order in the struct definition.
     ///
-    /// **Why is this bad?** Since the order of fields in a constructor doesn't affect the
+    /// ### Why is this bad?
+    /// Since the order of fields in a constructor doesn't affect the
     /// resulted instance as the below example indicates,
     ///
     /// ```rust
@@ -32,10 +34,7 @@ declare_clippy_lint! {
     ///
     /// inconsistent order can be confusing and decreases readability and consistency.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// struct Foo {
     ///     x: i32,

clippy_lints/src/indexing_slicing.rs

@@ -10,14 +10,17 @@ use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for out of bounds array indexing with a constant
+    /// ### What it does
+    /// Checks for out of bounds array indexing with a constant
     /// index.
     ///
-    /// **Why is this bad?** This will always panic at runtime.
+    /// ### Why is this bad?
+    /// This will always panic at runtime.
     ///
-    /// **Known problems:** Hopefully none.
+    /// ### Known problems
+    /// Hopefully none.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```no_run
     /// # #![allow(const_err)]
     /// let x = [1, 2, 3, 4];
@@ -36,16 +39,19 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of indexing or slicing. Arrays are special cases, this lint
+    /// ### What it does
+    /// Checks for usage of indexing or slicing. Arrays are special cases, this lint
     /// does report on arrays if we can tell that slicing operations are in bounds and does not
     /// lint on constant `usize` indexing on arrays because that is handled by rustc's `const_err` lint.
     ///
-    /// **Why is this bad?** Indexing and slicing can panic at runtime and there are
+    /// ### Why is this bad?
+    /// Indexing and slicing can panic at runtime and there are
     /// safe alternatives.
     ///
-    /// **Known problems:** Hopefully none.
+    /// ### Known problems
+    /// Hopefully none.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,no_run
     /// // Vector
     /// let x = vec![0; 5];

clippy_lints/src/infinite_iter.rs

@@ -1,19 +1,20 @@
 use clippy_utils::diagnostics::span_lint;
-use clippy_utils::ty::{implements_trait, match_type};
+use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
 use clippy_utils::{get_trait_def_id, higher, is_qpath_def_path, paths};
 use rustc_hir::{BorrowKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol::{sym, Symbol};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for iteration that is guaranteed to be infinite.
+    /// ### What it does
+    /// Checks for iteration that is guaranteed to be infinite.
     ///
-    /// **Why is this bad?** While there may be places where this is acceptable
+    /// ### Why is this bad?
+    /// While there may be places where this is acceptable
     /// (e.g., in event streams), in most cases this is simply an error.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```no_run
     /// use std::iter;
     ///
@@ -25,15 +26,18 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for iteration that may be infinite.
+    /// ### What it does
+    /// Checks for iteration that may be infinite.
     ///
-    /// **Why is this bad?** While there may be places where this is acceptable
+    /// ### Why is this bad?
+    /// While there may be places where this is acceptable
     /// (e.g., in event streams), in most cases this is simply an error.
     ///
-    /// **Known problems:** The code may have a condition to stop iteration, but
+    /// ### Known problems
+    /// The code may have a condition to stop iteration, but
     /// this lint is not clever enough to analyze it.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let infinite_iter = 0..;
     /// [0..].iter().zip(infinite_iter.take_while(|x| *x > 5));
@@ -202,15 +206,15 @@ const COMPLETING_METHODS: [(&str, usize); 12] = [
 ];
 
 /// the paths of types that are known to be infinitely allocating
-const INFINITE_COLLECTORS: [&[&str]; 8] = [
-    &paths::BINARY_HEAP,
-    &paths::BTREEMAP,
-    &paths::BTREESET,
-    &paths::HASHMAP,
-    &paths::HASHSET,
-    &paths::LINKED_LIST,
-    &paths::VEC,
-    &paths::VEC_DEQUE,
+const INFINITE_COLLECTORS: &[Symbol] = &[
+    sym::BinaryHeap,
+    sym::BTreeMap,
+    sym::BTreeSet,
+    sym::hashmap_type,
+    sym::hashset_type,
+    sym::LinkedList,
+    sym::vec_type,
+    sym::vecdeque_type,
 ];
 
 fn complete_infinite_iter(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
@@ -235,7 +239,10 @@ fn complete_infinite_iter(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
                 }
             } else if method.ident.name == sym!(collect) {
                 let ty = cx.typeck_results().expr_ty(expr);
-                if INFINITE_COLLECTORS.iter().any(|path| match_type(cx, ty, path)) {
+                if INFINITE_COLLECTORS
+                    .iter()
+                    .any(|diag_item| is_type_diagnostic_item(cx, ty, *diag_item))
+                {
                     return is_infinite(cx, &args[0]);
                 }
             }

clippy_lints/src/inherent_impl.rs

@@ -10,13 +10,13 @@ use rustc_span::Span;
 use std::collections::hash_map::Entry;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for multiple inherent implementations of a struct
+    /// ### What it does
+    /// Checks for multiple inherent implementations of a struct
     ///
-    /// **Why is this bad?** Splitting the implementation of a type makes the code harder to navigate.
+    /// ### Why is this bad?
+    /// Splitting the implementation of a type makes the code harder to navigate.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// struct X;
     /// impl X {

clippy_lints/src/inherent_to_string.rs

@@ -8,14 +8,16 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for the definition of inherent methods with a signature of `to_string(&self) -> String`.
+    /// ### What it does
+    /// Checks for the definition of inherent methods with a signature of `to_string(&self) -> String`.
     ///
-    /// **Why is this bad?** This method is also implicitly defined if a type implements the `Display` trait. As the functionality of `Display` is much more versatile, it should be preferred.
+    /// ### Why is this bad?
+    /// This method is also implicitly defined if a type implements the `Display` trait. As the functionality of `Display` is much more versatile, it should be preferred.
     ///
-    /// **Known problems:** None
-    ///
-    /// ** Example:**
+    /// ### Known problems
+    /// None
     ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// pub struct A;
@@ -45,14 +47,16 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for the definition of inherent methods with a signature of `to_string(&self) -> String` and if the type implementing this method also implements the `Display` trait.
+    /// ### What it does
+    /// Checks for the definition of inherent methods with a signature of `to_string(&self) -> String` and if the type implementing this method also implements the `Display` trait.
     ///
-    /// **Why is this bad?** This method is also implicitly defined if a type implements the `Display` trait. The less versatile inherent method will then shadow the implementation introduced by `Display`.
+    /// ### Why is this bad?
+    /// This method is also implicitly defined if a type implements the `Display` trait. The less versatile inherent method will then shadow the implementation introduced by `Display`.
     ///
-    /// **Known problems:** None
-    ///
-    /// ** Example:**
+    /// ### Known problems
+    /// None
     ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// use std::fmt;

clippy_lints/src/inline_fn_without_body.rs

@@ -10,14 +10,14 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{sym, Symbol};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `#[inline]` on trait methods without bodies
+    /// ### What it does
+    /// Checks for `#[inline]` on trait methods without bodies
     ///
-    /// **Why is this bad?** Only implementations of trait methods may be inlined.
+    /// ### Why is this bad?
+    /// Only implementations of trait methods may be inlined.
     /// The inline attribute is ignored for trait methods without bodies.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// trait Animal {
     ///     #[inline]

clippy_lints/src/int_plus_one.rs

@@ -8,13 +8,13 @@ use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of `x >= y + 1` or `x - 1 >= y` (and `<=`) in a block
+    /// ### What it does
+    /// Checks for usage of `x >= y + 1` or `x - 1 >= y` (and `<=`) in a block
     ///
-    /// **Why is this bad?** Readability -- better to use `> y` instead of `>= y + 1`.
+    /// ### Why is this bad?
+    /// Readability -- better to use `> y` instead of `>= y + 1`.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// # let x = 1;
     /// # let y = 1;

clippy_lints/src/integer_division.rs

@@ -5,15 +5,15 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for division of integers
+    /// ### What it does
+    /// Checks for division of integers
     ///
-    /// **Why is this bad?** When outside of some very specific algorithms,
+    /// ### Why is this bad?
+    /// When outside of some very specific algorithms,
     /// integer division is very often a mistake because it discards the
     /// remainder.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// // Bad
     /// let x = 3 / 2;

clippy_lints/src/invalid_upcast_comparisons.rs

@@ -14,18 +14,20 @@ use clippy_utils::source::snippet;
 use clippy_utils::{comparisons, sext};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for comparisons where the relation is always either
+    /// ### What it does
+    /// Checks for comparisons where the relation is always either
     /// true or false, but where one side has been upcast so that the comparison is
     /// necessary. Only integer types are checked.
     ///
-    /// **Why is this bad?** An expression like `let x : u8 = ...; (x as u32) > 300`
+    /// ### Why is this bad?
+    /// An expression like `let x : u8 = ...; (x as u32) > 300`
     /// will mistakenly imply that it is possible for `x` to be outside the range of
     /// `u8`.
     ///
-    /// **Known problems:**
+    /// ### Known problems
     /// https://github.com/rust-lang/rust-clippy/issues/886
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// let x: u8 = 1;
     /// (x as u32) > 300;

clippy_lints/src/items_after_statements.rs

@@ -7,15 +7,15 @@ use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for items declared after some statement in a block.
+    /// ### What it does
+    /// Checks for items declared after some statement in a block.
     ///
-    /// **Why is this bad?** Items live for the entire scope they are declared
+    /// ### Why is this bad?
+    /// Items live for the entire scope they are declared
     /// in. But statements are processed in order. This might cause confusion as
     /// it's hard to figure out which item is meant in a statement.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// // Bad
     /// fn foo() {

clippy_lints/src/large_const_arrays.rs

@@ -11,15 +11,15 @@ use rustc_span::{BytePos, Pos, Span};
 use rustc_typeck::hir_ty_to_ty;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for large `const` arrays that should
+    /// ### What it does
+    /// Checks for large `const` arrays that should
     /// be defined as `static` instead.
     ///
-    /// **Why is this bad?** Performance: const variables are inlined upon use.
+    /// ### Why is this bad?
+    /// Performance: const variables are inlined upon use.
     /// Static items result in only one instance and has a fixed location in memory.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// // Bad
     /// pub const a = [0u32; 1_000_000];

clippy_lints/src/large_enum_variant.rs

@@ -10,20 +10,22 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_target::abi::LayoutOf;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for large size differences between variants on
+    /// ### What it does
+    /// Checks for large size differences between variants on
     /// `enum`s.
     ///
-    /// **Why is this bad?** Enum size is bounded by the largest variant. Having a
+    /// ### Why is this bad?
+    /// Enum size is bounded by the largest variant. Having a
     /// large variant can penalize the memory layout of that enum.
     ///
-    /// **Known problems:** This lint obviously cannot take the distribution of
+    /// ### Known problems
+    /// This lint obviously cannot take the distribution of
     /// variants in your running program into account. It is possible that the
     /// smaller variants make up less than 1% of all instances, in which case
     /// the overhead is negligible and the boxing is counter-productive. Always
     /// measure the change this lint suggests.
     ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// enum Test {

clippy_lints/src/large_stack_arrays.rs

@@ -10,13 +10,13 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use crate::rustc_target::abi::LayoutOf;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for local arrays that may be too large.
+    /// ### What it does
+    /// Checks for local arrays that may be too large.
     ///
-    /// **Why is this bad?** Large local arrays may cause stack overflow.
+    /// ### Why is this bad?
+    /// Large local arrays may cause stack overflow.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// let a = [0u32; 1_000_000];
     /// ```

clippy_lints/src/len_zero.rs

@@ -18,17 +18,17 @@ use rustc_span::{
 };
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for getting the length of something via `.len()`
+    /// ### What it does
+    /// Checks for getting the length of something via `.len()`
     /// just to compare to zero, and suggests using `.is_empty()` where applicable.
     ///
-    /// **Why is this bad?** Some structures can answer `.is_empty()` much faster
+    /// ### Why is this bad?
+    /// Some structures can answer `.is_empty()` much faster
     /// than calculating their length. So it is good to get into the habit of using
     /// `.is_empty()`, and having it is cheap.
     /// Besides, it makes the intent clearer than a manual comparison in some contexts.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// if x.len() == 0 {
     ///     ..
@@ -52,18 +52,18 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for items that implement `.len()` but not
+    /// ### What it does
+    /// Checks for items that implement `.len()` but not
     /// `.is_empty()`.
     ///
-    /// **Why is this bad?** It is good custom to have both methods, because for
+    /// ### Why is this bad?
+    /// It is good custom to have both methods, because for
     /// some data structures, asking about the length will be a costly operation,
     /// whereas `.is_empty()` can usually answer in constant time. Also it used to
     /// lead to false positives on the [`len_zero`](#len_zero) lint – currently that
     /// lint will ignore such entities.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// impl X {
     ///     pub fn len(&self) -> usize {
@@ -77,17 +77,17 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for comparing to an empty slice such as `""` or `[]`,
+    /// ### What it does
+    /// Checks for comparing to an empty slice such as `""` or `[]`,
     /// and suggests using `.is_empty()` where applicable.
     ///
-    /// **Why is this bad?** Some structures can answer `.is_empty()` much faster
+    /// ### Why is this bad?
+    /// Some structures can answer `.is_empty()` much faster
     /// than checking for equality. So it is good to get into the habit of using
     /// `.is_empty()`, and having it is cheap.
     /// Besides, it makes the intent clearer than a manual comparison in some contexts.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     ///
     /// ```ignore
     /// if s == "" {

clippy_lints/src/let_if_seq.rs

@@ -9,14 +9,14 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for variable declarations immediately followed by a
+    /// ### What it does
+    /// Checks for variable declarations immediately followed by a
     /// conditional affectation.
     ///
-    /// **Why is this bad?** This is not idiomatic Rust.
+    /// ### Why is this bad?
+    /// This is not idiomatic Rust.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// let foo;
     ///

clippy_lints/src/let_underscore.rs

@@ -9,15 +9,15 @@ use rustc_middle::ty::subst::GenericArgKind;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `let _ = <expr>`
+    /// ### What it does
+    /// Checks for `let _ = <expr>`
     /// where expr is #[must_use]
     ///
-    /// **Why is this bad?** It's better to explicitly
+    /// ### Why is this bad?
+    /// It's better to explicitly
     /// handle the value of a #[must_use] expr
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// fn f() -> Result<u32, u32> {
     ///     Ok(0)
@@ -33,17 +33,17 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `let _ = sync_lock`
+    /// ### What it does
+    /// Checks for `let _ = sync_lock`
     ///
-    /// **Why is this bad?** This statement immediately drops the lock instead of
+    /// ### Why is this bad?
+    /// This statement immediately drops the lock instead of
     /// extending its lifetime to the end of the scope, which is often not intended.
     /// To extend lock lifetime to the end of the scope, use an underscore-prefixed
     /// name instead (i.e. _lock). If you want to explicitly drop the lock,
     /// `std::mem::drop` conveys your intention better and is less error-prone.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     ///
     /// Bad:
     /// ```rust,ignore
@@ -60,19 +60,19 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for `let _ = <expr>`
+    /// ### What it does
+    /// Checks for `let _ = <expr>`
     /// where expr has a type that implements `Drop`
     ///
-    /// **Why is this bad?** This statement immediately drops the initializer
+    /// ### Why is this bad?
+    /// This statement immediately drops the initializer
     /// expression instead of extending its lifetime to the end of the scope, which
     /// is often not intended. To extend the expression's lifetime to the end of the
     /// scope, use an underscore-prefixed name instead (i.e. _var). If you want to
     /// explicitly drop the expression, `std::mem::drop` conveys your intention
     /// better and is less error-prone.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     ///
     /// Bad:
     /// ```rust,ignore

clippy_lints/src/lib.rs

@@ -73,14 +73,13 @@ use rustc_session::Session;
 /// use clippy_lints::declare_clippy_lint;
 ///
 /// declare_clippy_lint! {
-///     /// **What it does:** Checks for ... (describe what the lint matches).
+///     /// ### What it does
+///     /// Checks for ... (describe what the lint matches).
 ///     ///
-///     /// **Why is this bad?** Supply the reason for linting the code.
-///     ///
-///     /// **Known problems:** None. (Or describe where it could go wrong.)
-///     ///
-///     /// **Example:**
+///     /// ### Why is this bad?
+///     /// Supply the reason for linting the code.
 ///     ///
+///     /// ### Example
 ///     /// ```rust
 ///     /// // Bad
 ///     /// Insert a short example of code that triggers the lint
@@ -330,7 +329,7 @@ mod regex;
 mod repeat_once;
 mod returns;
 mod self_assignment;
-mod self_named_constructor;
+mod self_named_constructors;
 mod semicolon_if_nothing_returned;
 mod serde_api;
 mod shadow;
@@ -741,7 +740,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         mem_replace::MEM_REPLACE_OPTION_WITH_NONE,
         mem_replace::MEM_REPLACE_WITH_DEFAULT,
         mem_replace::MEM_REPLACE_WITH_UNINIT,
-        methods::APPEND_INSTEAD_OF_EXTEND,
         methods::BIND_INSTEAD_OF_MAP,
         methods::BYTES_NTH,
         methods::CHARS_LAST_CMP,
@@ -752,6 +750,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         methods::CLONE_ON_REF_PTR,
         methods::EXPECT_FUN_CALL,
         methods::EXPECT_USED,
+        methods::EXTEND_WITH_DRAIN,
         methods::FILETYPE_IS_FILE,
         methods::FILTER_MAP_IDENTITY,
         methods::FILTER_MAP_NEXT,
@@ -901,7 +900,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         returns::LET_AND_RETURN,
         returns::NEEDLESS_RETURN,
         self_assignment::SELF_ASSIGNMENT,
-        self_named_constructor::SELF_NAMED_CONSTRUCTOR,
+        self_named_constructors::SELF_NAMED_CONSTRUCTORS,
         semicolon_if_nothing_returned::SEMICOLON_IF_NOTHING_RETURNED,
         serde_api::SERDE_API_MISUSE,
         shadow::SHADOW_REUSE,
@@ -1297,7 +1296,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(mem_replace::MEM_REPLACE_OPTION_WITH_NONE),
         LintId::of(mem_replace::MEM_REPLACE_WITH_DEFAULT),
         LintId::of(mem_replace::MEM_REPLACE_WITH_UNINIT),
-        LintId::of(methods::APPEND_INSTEAD_OF_EXTEND),
         LintId::of(methods::BIND_INSTEAD_OF_MAP),
         LintId::of(methods::BYTES_NTH),
         LintId::of(methods::CHARS_LAST_CMP),
@@ -1305,6 +1303,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(methods::CLONE_DOUBLE_REF),
         LintId::of(methods::CLONE_ON_COPY),
         LintId::of(methods::EXPECT_FUN_CALL),
+        LintId::of(methods::EXTEND_WITH_DRAIN),
         LintId::of(methods::FILTER_MAP_IDENTITY),
         LintId::of(methods::FILTER_NEXT),
         LintId::of(methods::FLAT_MAP_IDENTITY),
@@ -1408,7 +1407,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(returns::LET_AND_RETURN),
         LintId::of(returns::NEEDLESS_RETURN),
         LintId::of(self_assignment::SELF_ASSIGNMENT),
-        LintId::of(self_named_constructor::SELF_NAMED_CONSTRUCTOR),
+        LintId::of(self_named_constructors::SELF_NAMED_CONSTRUCTORS),
         LintId::of(serde_api::SERDE_API_MISUSE),
         LintId::of(single_component_path_imports::SINGLE_COMPONENT_PATH_IMPORTS),
         LintId::of(size_of_in_element_count::SIZE_OF_IN_ELEMENT_COUNT),
@@ -1562,7 +1561,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(redundant_static_lifetimes::REDUNDANT_STATIC_LIFETIMES),
         LintId::of(returns::LET_AND_RETURN),
         LintId::of(returns::NEEDLESS_RETURN),
-        LintId::of(self_named_constructor::SELF_NAMED_CONSTRUCTOR),
+        LintId::of(self_named_constructors::SELF_NAMED_CONSTRUCTORS),
         LintId::of(single_component_path_imports::SINGLE_COMPONENT_PATH_IMPORTS),
         LintId::of(tabs_in_doc_comments::TABS_IN_DOC_COMMENTS),
         LintId::of(to_digit_is_some::TO_DIGIT_IS_SOME),
@@ -1763,8 +1762,8 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(large_enum_variant::LARGE_ENUM_VARIANT),
         LintId::of(loops::MANUAL_MEMCPY),
         LintId::of(loops::NEEDLESS_COLLECT),
-        LintId::of(methods::APPEND_INSTEAD_OF_EXTEND),
         LintId::of(methods::EXPECT_FUN_CALL),
+        LintId::of(methods::EXTEND_WITH_DRAIN),
         LintId::of(methods::ITER_NTH),
         LintId::of(methods::MANUAL_STR_REPEAT),
         LintId::of(methods::OR_FUN_CALL),
@@ -2105,7 +2104,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     let scripts = conf.allowed_scripts.clone();
     store.register_early_pass(move || box disallowed_script_idents::DisallowedScriptIdents::new(&scripts));
     store.register_late_pass(|| box strlen_on_c_strings::StrlenOnCStrings);
-    store.register_late_pass(move || box self_named_constructor::SelfNamedConstructor);
+    store.register_late_pass(move || box self_named_constructors::SelfNamedConstructors);
 }
 
 #[rustfmt::skip]

clippy_lints/src/lifetimes.rs

@@ -18,20 +18,22 @@ use rustc_span::source_map::Span;
 use rustc_span::symbol::{kw, Symbol};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for lifetime annotations which can be removed by
+    /// ### What it does
+    /// Checks for lifetime annotations which can be removed by
     /// relying on lifetime elision.
     ///
-    /// **Why is this bad?** The additional lifetimes make the code look more
+    /// ### Why is this bad?
+    /// The additional lifetimes make the code look more
     /// complicated, while there is nothing out of the ordinary going on. Removing
     /// them leads to more readable code.
     ///
-    /// **Known problems:**
+    /// ### Known problems
     /// - We bail out if the function has a `where` clause where lifetimes
     /// are mentioned due to potenial false positives.
     /// - Lifetime bounds such as `impl Foo + 'a` and `T: 'a` must be elided with the
     /// placeholder notation `'_` because the fully elided notation leaves the type bound to `'static`.
     ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// // Bad: unnecessary lifetime annotations
     /// fn in_and_out<'a>(x: &'a u8, y: u8) -> &'a u8 {
@@ -50,16 +52,16 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for lifetimes in generics that are never used
+    /// ### What it does
+    /// Checks for lifetimes in generics that are never used
     /// anywhere else.
     ///
-    /// **Why is this bad?** The additional lifetimes make the code look more
+    /// ### Why is this bad?
+    /// The additional lifetimes make the code look more
     /// complicated, while there is nothing out of the ordinary going on. Removing
     /// them leads to more readable code.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// // Bad: unnecessary lifetimes
     /// fn unused_lifetime<'a>(x: u8) {