add `explain` subcommand and explanations to all lints

1 files changed, 32 insertions, 5 deletions

diff --git a/lib/src/lints/collapsible_let_in.rs b/lib/src/lints/collapsible_let_in.rs
index 878d218..21199a8 100644
--- a/lib/src/lints/collapsible_let_in.rs
+++ b/lib/src/lints/collapsible_let_in.rs
@@ -1,13 +1,41 @@
-use crate::{make, Lint, Metadata, Report, Rule, Suggestion};
+use crate::{make, Metadata, Report, Rule, Suggestion};
 
 use if_chain::if_chain;
 use macros::lint;
-use rowan::Direction;
 use rnix::{
     types::{LetIn, TypedNode},
-    NodeOrToken, SyntaxElement, SyntaxKind, TextRange
+    NodeOrToken, SyntaxElement, SyntaxKind, TextRange,
 };
+use rowan::Direction;
 
+/// ## What it does
+/// Checks for `let-in` expressions whose body is another `let-in`
+/// expression.
+///
+/// ## Why is this bad?
+/// Unnecessary code, the `let-in` expressions can be merged.
+///
+/// ## Example
+///
+/// ```
+/// let
+///   a = 2;
+/// in
+/// let
+///   b = 3;
+/// in
+///   a + b
+/// ```
+///
+/// Merge both `let-in` expressions:
+///
+/// ```
+/// let
+///   a = 2;
+///   b = 3;
+/// in
+///   a + b
+/// ```
 #[lint(
     name = "collapsible let in",
     note = "These let-in expressions are collapsible",
@@ -47,7 +75,7 @@ impl Rule for CollapsibleLetIn {
                 let replacement = make::empty().node().clone();
 
                 Some(
-                    Self::report()
+                    self.report()
                         .diagnostic(first_annotation, first_message)
                         .suggest(second_annotation, second_message, Suggestion::new(replacement_at, replacement))
                 )
@@ -57,4 +85,3 @@ impl Rule for CollapsibleLetIn {
         }
     }
 }
-