Merge pull request #3038 from matthiaskrgr/clippy_docs

docs: add more suggestions on how to fix clippy findings to the online lint list

clippy_lints/src/len_zero.rs

@@ -22,6 +22,12 @@
 /// **Example:**
 /// ```rust
 /// if x.len() == 0 { .. }
+/// if y.len() != 0 { .. }
+/// ```
+/// instead use
+/// ```rust
+/// if x.len().is_empty() { .. }
+/// if !y.len().is_empty() { .. }
 /// ```
 declare_clippy_lint! {
     pub LEN_ZERO,

clippy_lints/src/loops.rs

@@ -80,6 +80,10 @@
 /// // with `y` a `Vec` or slice:
 /// for x in y.iter() { .. }
 /// ```
+/// can be rewritten to
+/// ```rust
+/// for x in &y { .. }
+/// ```
 declare_clippy_lint! {
     pub EXPLICIT_ITER_LOOP,
     style,
@@ -98,6 +102,10 @@
 /// // with `y` a `Vec` or slice:
 /// for x in y.into_iter() { .. }
 /// ```
+/// can be rewritten to
+/// ```rust
+/// for x in y { .. }
+/// ```
 declare_clippy_lint! {
     pub EXPLICIT_INTO_ITER_LOOP,
     style,

clippy_lints/src/matches.rs

@@ -93,6 +93,15 @@
 ///     false => bar(),
 /// }
 /// ```
+/// Use if/else instead:
+/// ```rust
+/// let condition: bool = true;
+/// if condition {
+///     foo();
+/// } else {
+///     bar();
+/// }
+/// ```
 declare_clippy_lint! {
     pub MATCH_BOOL,
     style,

clippy_lints/src/methods.rs

@@ -448,7 +448,7 @@
 /// **Known problems:** Does not catch multi-byte unicode characters.
 ///
 /// **Example:**
-/// `_.split("x")` could be `_.split('x')
+/// `_.split("x")` could be `_.split('x')`
 declare_clippy_lint! {
     pub SINGLE_CHAR_PATTERN,
     perf,
@@ -468,7 +468,7 @@
 /// ```rust,ignore
 /// let c_str = CString::new("foo").unwrap().as_ptr();
 /// unsafe {
-/// call_some_ffi_func(c_str);
+///     call_some_ffi_func(c_str);
 /// }
 /// ```
 /// Here `c_str` point to a freed address. The correct use would be:

clippy_lints/src/redundant_field_names.rs

@@ -21,6 +21,10 @@
 ///
 /// let foo = Foo{ bar: bar }
 /// ```
+/// the last line can be simplified to
+/// ```rust
+/// let foo = Foo{ bar }
+/// ```
 declare_clippy_lint! {
     pub REDUNDANT_FIELD_NAMES,
     style,

clippy_lints/src/returns.rs

@@ -19,6 +19,10 @@
 /// ```rust
 /// fn foo(x: usize) { return x; }
 /// ```
+/// simplify to
+/// ```rust
+/// fn foo(x: usize) { x }
+/// ```
 declare_clippy_lint! {
     pub NEEDLESS_RETURN,
     style,
@@ -35,7 +39,16 @@
 ///
 /// **Example:**
 /// ```rust
-/// { let x = ..; x }
+/// fn foo() -> String {
+///    let x = String::new();
+///    x
+///}
+/// ```
+/// instead, use
+/// ```
+/// fn foo() -> String {
+///    String::new()
+///}
 /// ```
 declare_clippy_lint! {
     pub LET_AND_RETURN,

clippy_lints/src/shadow.rs

@@ -42,6 +42,10 @@
 /// ```rust
 /// let x = x + 1;
 /// ```
+/// use different variable name:
+/// ```rust
+/// let y = x + 1;
+/// ```
 declare_clippy_lint! {
     pub SHADOW_REUSE,
     restriction,

clippy_lints/src/write.rs

@@ -35,6 +35,10 @@
 /// ```rust
 /// print!("Hello {}!\n", name);
 /// ```
+/// use println!() instead
+/// ```rust
+/// println!("Hello {}!", name);
+/// ```
 declare_clippy_lint! {
     pub PRINT_WITH_NEWLINE,
     style,
@@ -88,6 +92,10 @@
 /// ```rust
 /// println!("{}", "foo");
 /// ```
+/// use the literal without formatting:
+/// ```rust
+/// println!("foo");
+/// ```
 declare_clippy_lint! {
     pub PRINT_LITERAL,
     style,