make redundant_local's find_binding more readable

Author: max-niederman

clippy_lints/src/redundant_local.rs

@@ -78,25 +78,15 @@ impl<'tcx> LateLintPass<'tcx> for RedundantLocal {
 
 /// Find the annotation of a binding introduced by a pattern, or `None` if it's not introduced.
 fn find_binding(pat: &Pat<'_>, name: Ident) -> Option<BindingAnnotation> {
-    match pat.kind {
-        PatKind::Binding(annotation, _, ident, _) if ident == name => Some(annotation),
-        PatKind::Binding(_, _, _, Some(subpat)) => find_binding(subpat, name),
-        PatKind::Struct(_, fields, _) => fields.iter().find_map(|field| find_binding(field.pat, name)),
-        PatKind::TupleStruct(_, fields, _) | PatKind::Or(fields) | PatKind::Tuple(fields, _) => {
-            fields.iter().find_map(|field| find_binding(field, name))
-        },
-        PatKind::Slice(before, middle, after) => before
-            .iter()
-            .chain(middle)
-            .chain(after.iter())
-            .find_map(|field| find_binding(field, name)),
-        PatKind::Box(inner) | PatKind::Ref(inner, _) => find_binding(inner, name),
-        PatKind::Wild
-        | PatKind::Binding(_, _, _, None)
-        | PatKind::Path(_)
-        | PatKind::Lit(_)
-        | PatKind::Range(_, _, _) => None,
-    }
+    let mut ret = None;
+
+    pat.each_binding_or_first(&mut |annotation, _, _, ident| {
+        if ident == name {
+            ret = Some(annotation);
+        }
+    });
+
+    ret
 }
 
 /// Check if a rebinding of a local affects the code's drop behavior.