Add lint for overindented list items in docs

Add a lint to detect and fix list items in docs that are overindented.

For example,

```rs
/// - first line
///      second line
fn foo() {}
```

this would be fixed to:

```rs
/// - first line
///   second line
fn foo() {}
```

This lint improves readabiliy and consistency in doc.

Author: ohno418

README.md

@@ -159,11 +159,11 @@ line. (You can swap `clippy::all` with the specific lint category you are target
 You can add options to your code to `allow`/`warn`/`deny` Clippy lints:
 
 * the whole set of `Warn` lints using the `clippy` lint group (`#![deny(clippy::all)]`).
-    Note that `rustc` has additional [lint groups](https://doc.rust-lang.org/rustc/lints/groups.html).
+  Note that `rustc` has additional [lint groups](https://doc.rust-lang.org/rustc/lints/groups.html).
 
 * all lints using both the `clippy` and `clippy::pedantic` lint groups (`#![deny(clippy::all)]`,
-    `#![deny(clippy::pedantic)]`). Note that `clippy::pedantic` contains some very aggressive
-    lints prone to false positives.
+  `#![deny(clippy::pedantic)]`). Note that `clippy::pedantic` contains some very aggressive
+  lints prone to false positives.
 
 * only some lints (`#![deny(clippy::single_match, clippy::box_vec)]`, etc.)
 

clippy_lints/src/doc/lazy_continuation.rs

@@ -28,41 +28,15 @@ pub(super) fn check(
         return;
     }
 
+    // Handle blockquotes.
     let ccount = doc[range.clone()].chars().filter(|c| *c == '>').count();
     let blockquote_level = containers
         .iter()
         .filter(|c| matches!(c, super::Container::Blockquote))
         .count();
-    let lcount = doc[range.clone()].chars().filter(|c| *c == ' ').count();
-    let list_indentation = containers
-        .iter()
-        .map(|c| {
-            if let super::Container::List(indent) = c {
-                *indent
-            } else {
-                0
-            }
-        })
-        .sum();
-    if ccount < blockquote_level || lcount < list_indentation {
-        let msg = if ccount < blockquote_level {
-            "doc quote line without `>` marker"
-        } else {
-            "doc list item without indentation"
-        };
+    if ccount < blockquote_level {
+        let msg = "doc quote line without `>` marker";
         span_lint_and_then(cx, DOC_LAZY_CONTINUATION, span, msg, |diag| {
-            if ccount == 0 && blockquote_level == 0 {
-                // simpler suggestion style for indentation
-                let indent = list_indentation - lcount;
-                diag.span_suggestion_verbose(
-                    span.shrink_to_hi(),
-                    "indent this line",
-                    std::iter::repeat(" ").take(indent).join(""),
-                    Applicability::MaybeIncorrect,
-                );
-                diag.help("if this is supposed to be its own paragraph, add a blank line");
-                return;
-            }
             let mut doc_start_range = &doc[range];
             let mut suggested = String::new();
             for c in containers {
@@ -89,5 +63,51 @@ pub(super) fn check(
             );
             diag.help("if this not intended to be a quote at all, escape it with `\\>`");
         });
+        return;
+    }
+
+    if ccount != 0 || blockquote_level != 0 {
+        // If this doc is a blockquote, we don't go further.
+        return;
+    }
+
+    // Handle list items
+    let lcount = doc[range.clone()].chars().filter(|c| *c == ' ').count();
+    let list_indentation = containers
+        .iter()
+        .map(|c| {
+            if let super::Container::List(indent) = c {
+                *indent
+            } else {
+                0
+            }
+        })
+        .sum();
+    if lcount != list_indentation {
+        let msg = if lcount < list_indentation {
+            "doc list item without indentation"
+        } else {
+            "doc list item overindented"
+        };
+        span_lint_and_then(cx, DOC_LAZY_CONTINUATION, span, msg, |diag| {
+            if lcount < list_indentation {
+                // simpler suggestion style for indentation
+                let indent = list_indentation - lcount;
+                diag.span_suggestion_verbose(
+                    span.shrink_to_hi(),
+                    "indent this line",
+                    std::iter::repeat(" ").take(indent).join(""),
+                    Applicability::MaybeIncorrect,
+                );
+            } else {
+                diag.span_suggestion_verbose(
+                    span,
+                    "indent this line",
+                    std::iter::repeat(" ").take(list_indentation).join(""),
+                    Applicability::MaybeIncorrect,
+                );
+            }
+            diag.help("if this is supposed to be its own paragraph, add a blank line");
+        });
     }
 }

tests/ui/doc/doc_lazy_list.fixed

@@ -52,26 +52,32 @@ fn seven() {}
 ///
 /// # Arguments
 /// * `protocol_descriptors`: A Json Representation of the ProtocolDescriptors
-///     to set up. Example:
+///   to set up. Example:
 ///   'protocol_descriptors': [
 //~^ ERROR: doc list item without indentation
-///      {
-///          'protocol': 25,  # u64 Representation of ProtocolIdentifier::AVDTP
-///          'params': [
-///              {
-///                 'data': 0x0103  # to indicate 1.3
-///              },
-///              {
-///                  'data': 0x0105  # to indicate 1.5
-///              }
+///   {
+///   'protocol': 25,  # u64 Representation of ProtocolIdentifier::AVDTP
+///   'params': [
+///   {
+///   'data': 0x0103  # to indicate 1.3
+///   },
+///   {
+///   'data': 0x0105  # to indicate 1.5
+///   }
 ///          ]
-///      },
-///      {
-///          'protocol': 1,  # u64 Representation of ProtocolIdentifier::SDP
-///          'params': [{
-///              'data': 0x0019
-///          }]
-///      }
+///   },
+///   {
+///   'protocol': 1,  # u64 Representation of ProtocolIdentifier::SDP
+///   'params': [{
+///   'data': 0x0019
+///   }]
+///   }
 ///   ]
 //~^ ERROR: doc list item without indentation
 fn eight() {}
+
+#[rustfmt::skip]
+/// - first line
+///   second line
+//~^ ERROR: doc list item overindented
+fn nine() {}

tests/ui/doc/doc_lazy_list.rs

@@ -75,3 +75,9 @@ fn seven() {}
 ///  ]
 //~^ ERROR: doc list item without indentation
 fn eight() {}
+
+#[rustfmt::skip]
+/// - first line
+///      second line
+//~^ ERROR: doc list item overindented
+fn nine() {}