Rollup of 4 pull requests

clippy_lints/src/arithmetic.rs

@@ -16,7 +16,8 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// a + 1
+    /// # let a = 0;
+    /// a + 1;
     /// ```
     pub INTEGER_ARITHMETIC,
     restriction,
@@ -33,7 +34,8 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// a + 1.0
+    /// # let a = 0.0;
+    /// a + 1.0;
     /// ```
     pub FLOAT_ARITHMETIC,
     restriction,

clippy_lints/src/attrs.rs

@@ -113,19 +113,19 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// // Bad
-    /// #[inline(always)]
-    ///
-    /// fn not_quite_good_code(..) { ... }
-    ///
     /// // Good (as inner attribute)
     /// #![inline(always)]
     ///
-    /// fn this_is_fine(..) { ... }
+    /// fn this_is_fine() { }
+    ///
+    /// // Bad
+    /// #[inline(always)]
+    ///
+    /// fn not_quite_good_code() { }
     ///
     /// // Good (as outer attribute)
     /// #[inline(always)]
-    /// fn this_is_fine_too(..) { ... }
+    /// fn this_is_fine_too() { }
     /// ```
     pub EMPTY_LINE_AFTER_OUTER_ATTR,
     nursery,

clippy_lints/src/checked_conversions.rs

@@ -27,6 +27,8 @@ declare_clippy_lint! {
     /// Could be written:
     ///
     /// ```rust
+    /// # use std::convert::TryFrom;
+    /// # let foo = 1;
     /// # let _ =
     /// i32::try_from(foo).is_ok()
     /// # ;

clippy_lints/src/copy_iterator.rs

@@ -13,7 +13,7 @@ declare_clippy_lint! {
     /// **Known problems:** None.
     ///
     /// **Example:**
-    /// ```rust
+    /// ```rust,ignore
     /// #[derive(Copy, Clone)]
     /// struct Countdown(u8);
     ///

clippy_lints/src/derive.rs

@@ -49,12 +49,12 @@ declare_clippy_lint! {
     /// **Known problems:** Bounds of generic types are sometimes wrong: https://github.com/rust-lang/rust/issues/26925
     ///
     /// **Example:**
-    /// ```rust
+    /// ```rust,ignore
     /// #[derive(Copy)]
     /// struct Foo;
     ///
     /// impl Clone for Foo {
-    ///     ..
+    ///     // ..
     /// }
     /// ```
     pub EXPL_IMPL_CLONE_ON_COPY,

clippy_lints/src/doc.rs

@@ -27,7 +27,7 @@ declare_clippy_lint! {
     /// /// Do something with the foo_bar parameter. See also
     /// /// that::other::module::foo.
     /// // ^ `foo_bar` and `that::other::module::foo` should be ticked.
-    /// fn doit(foo_bar) { .. }
+    /// fn doit(foo_bar: usize) {}
     /// ```
     pub DOC_MARKDOWN,
     pedantic,

clippy_lints/src/else_if_without_else.rs

@@ -16,6 +16,9 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
+    /// # fn a() {}
+    /// # fn b() {}
+    /// # let x: i32 = 1;
     /// if x.is_positive() {
     ///     a();
     /// } else if x.is_negative() {
@@ -26,6 +29,9 @@ declare_clippy_lint! {
     /// Could be written:
     ///
     /// ```rust
+    /// # fn a() {}
+    /// # fn b() {}
+    /// # let x: i32 = 1;
     /// if x.is_positive() {
     ///     a();
     /// } else if x.is_negative() {

clippy_lints/src/if_not_else.rs

@@ -17,6 +17,9 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
+    /// # let v: Vec<usize> = vec![];
+    /// # fn a() {}
+    /// # fn b() {}
     /// if !v.is_empty() {
     ///     a()
     /// } else {
@@ -27,6 +30,9 @@ declare_clippy_lint! {
     /// Could be written:
     ///
     /// ```rust
+    /// # let v: Vec<usize> = vec![];
+    /// # fn a() {}
+    /// # fn b() {}
     /// if v.is_empty() {
     ///     b()
     /// } else {

clippy_lints/src/indexing_slicing.rs

@@ -47,7 +47,7 @@ declare_clippy_lint! {
     /// **Known problems:** Hopefully none.
     ///
     /// **Example:**
-    /// ```rust
+    /// ```rust,no_run
     /// // Vector
     /// let x = vec![0; 5];
     ///

clippy_lints/src/infinite_iter.rs

@@ -34,7 +34,8 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// [0..].iter().zip(infinite_iter.take_while(|x| x > 5))
+    /// let infinite_iter = 0..;
+    /// [0..].iter().zip(infinite_iter.take_while(|x| *x > 5));
     /// ```
     pub MAYBE_INFINITE_ITER,
     pedantic,

clippy_lints/src/lib.rs

@@ -110,12 +110,12 @@ macro_rules! declare_clippy_lint {
     };
     { $(#[$attr:meta])* pub $name:tt, pedantic, $description:tt } => {
         declare_tool_lint! {
-            pub clippy::$name, Allow, $description, report_in_external_macro: true
+            $(#[$attr])* pub clippy::$name, Allow, $description, report_in_external_macro: true
         }
     };
     { $(#[$attr:meta])* pub $name:tt, restriction, $description:tt } => {
         declare_tool_lint! {
-            pub clippy::$name, Allow, $description, report_in_external_macro: true
+            $(#[$attr])* pub clippy::$name, Allow, $description, report_in_external_macro: true
         }
     };
     { $(#[$attr:meta])* pub $name:tt, cargo, $description:tt } => {
@@ -125,7 +125,7 @@ macro_rules! declare_clippy_lint {
     };
     { $(#[$attr:meta])* pub $name:tt, nursery, $description:tt } => {
         declare_tool_lint! {
-            pub clippy::$name, Allow, $description, report_in_external_macro: true
+            $(#[$attr])* pub clippy::$name, Allow, $description, report_in_external_macro: true
         }
     };
     { $(#[$attr:meta])* pub $name:tt, internal, $description:tt } => {

clippy_lints/src/loops.rs

@@ -91,16 +91,18 @@ declare_clippy_lint! {
     /// types.
     ///
     /// **Example:**
-    /// ```ignore
+    /// ```rust
     /// // with `y` a `Vec` or slice:
+    /// # let y = vec![1];
     /// for x in y.iter() {
-    ///     ..
+    ///     // ..
     /// }
     /// ```
     /// can be rewritten to
     /// ```rust
+    /// # let y = vec![1];
     /// for x in &y {
-    ///     ..
+    ///     // ..
     /// }
     /// ```
     pub EXPLICIT_ITER_LOOP,
@@ -117,16 +119,18 @@ declare_clippy_lint! {
     /// **Known problems:** None
     ///
     /// **Example:**
-    /// ```ignore
+    /// ```rust
+    /// # let y = vec![1];
     /// // with `y` a `Vec` or slice:
     /// for x in y.into_iter() {
-    ///     ..
+    ///     // ..
     /// }
     /// ```
     /// can be rewritten to
-    /// ```ignore
+    /// ```rust
+    /// # let y = vec![1];
     /// for x in y {
-    ///     ..
+    ///     // ..
     /// }
     /// ```
     pub EXPLICIT_INTO_ITER_LOOP,

clippy_lints/src/matches.rs

@@ -53,19 +53,25 @@ declare_clippy_lint! {
     /// Using `match`:
     ///
     /// ```rust
+    /// # fn bar(foo: &usize) {}
+    /// # let other_ref: usize = 1;
+    /// # let x: Option<&usize> = Some(&1);
     /// match x {
     ///     Some(ref foo) => bar(foo),
-    ///     _ => bar(other_ref),
+    ///     _ => bar(&other_ref),
     /// }
     /// ```
     ///
     /// Using `if let` with `else`:
     ///
     /// ```rust
+    /// # fn bar(foo: &usize) {}
+    /// # let other_ref: usize = 1;
+    /// # let x: Option<&usize> = Some(&1);
     /// if let Some(ref foo) = x {
     ///     bar(foo);
     /// } else {
-    ///     bar(other_ref);
+    ///     bar(&other_ref);
     /// }
     /// ```
     pub SINGLE_MATCH_ELSE,
@@ -205,6 +211,8 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
+    /// # enum Foo { A(usize), B(usize) }
+    /// # let x = Foo::B(1);
     /// match x {
     ///     A => {},
     ///     _ => {},

clippy_lints/src/mem_forget.rs

@@ -14,6 +14,8 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
+    /// # use std::mem;
+    /// # use std::rc::Rc;
     /// mem::forget(Rc::new(55))
     /// ```
     pub MEM_FORGET,

clippy_lints/src/methods/mod.rs

@@ -40,8 +40,19 @@ declare_clippy_lint! {
     /// **Known problems:** None.
     ///
     /// **Example:**
+    ///
+    /// Using unwrap on an `Option`:
+    ///
     /// ```rust
-    /// x.unwrap()
+    /// let opt = Some(1);
+    /// opt.unwrap();
+    /// ```
+    ///
+    /// Better:
+    ///
+    /// ```rust
+    /// let opt = Some(1);
+    /// opt.expect("more helpful message");
     /// ```
     pub OPTION_UNWRAP_USED,
     restriction,
@@ -62,8 +73,18 @@ declare_clippy_lint! {
     /// **Known problems:** None.
     ///
     /// **Example:**
+    /// Using unwrap on an `Option`:
+    ///
     /// ```rust
-    /// x.unwrap()
+    /// let res: Result<usize, ()> = Ok(1);
+    /// res.unwrap();
+    /// ```
+    ///
+    /// Better:
+    ///
+    /// ```rust
+    /// let res: Result<usize, ()> = Ok(1);
+    /// res.expect("more helpful message");
     /// ```
     pub RESULT_UNWRAP_USED,
     restriction,
@@ -141,9 +162,10 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// impl X {
-    ///     pub fn as_str(self) -> &str {
-    ///         ..
+    /// # struct X;
+    /// impl<'a> X {
+    ///     pub fn as_str(self) -> &'a str {
+    ///         "foo"
     ///     }
     /// }
     /// ```
@@ -179,7 +201,8 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// x.map(|a| a + 1).unwrap_or(0)
+    /// # let x = Some(1);
+    /// x.map(|a| a + 1).unwrap_or(0);
     /// ```
     pub OPTION_MAP_UNWRAP_OR,
     pedantic,
@@ -196,7 +219,9 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// x.map(|a| a + 1).unwrap_or_else(some_function)
+    /// # let x = Some(1);
+    /// # fn some_function() -> usize { 1 }
+    /// x.map(|a| a + 1).unwrap_or_else(some_function);
     /// ```
     pub OPTION_MAP_UNWRAP_OR_ELSE,
     pedantic,
@@ -213,7 +238,9 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// x.map(|a| a + 1).unwrap_or_else(some_function)
+    /// # let x: Result<usize, ()> = Ok(1);
+    /// # fn some_function(foo: ()) -> usize { 1 }
+    /// x.map(|a| a + 1).unwrap_or_else(some_function);
     /// ```
     pub RESULT_MAP_UNWRAP_OR_ELSE,
     pedantic,
@@ -265,7 +292,8 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// iter.map(|x| x.iter()).flatten()
+    /// let vec = vec![vec![1]];
+    /// vec.iter().map(|x| x.iter()).flatten();
     /// ```
     pub MAP_FLATTEN,
     pedantic,
@@ -284,7 +312,8 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// iter.filter(|x| x == 0).map(|x| x * 2)
+    /// let vec = vec![1];
+    /// vec.iter().filter(|x| **x == 0).map(|x| *x * 2);
     /// ```
     pub FILTER_MAP,
     pedantic,
@@ -324,7 +353,7 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    ///  (0..3).find(|x| x == 2).map(|x| x * 2);
+    ///  (0..3).find(|x| *x == 2).map(|x| x * 2);
     /// ```
     /// Can be written as
     /// ```rust
@@ -467,7 +496,9 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// x.clone()
+    /// # use std::rc::Rc;
+    /// let x = Rc::new(1);
+    /// x.clone();
     /// ```
     pub CLONE_ON_REF_PTR,
     restriction,