src/tools/clippy/clippy_lints/src/misc_early/redundant_pattern.rs

   1 use clippy_utils::diagnostics::span_lint_and_sugg;
   2 use rustc_ast::ast::{BindingMode, Mutability, Pat, PatKind};
   3 use rustc_errors::Applicability;
   4 use rustc_lint::EarlyContext;
   5
   6 use super::REDUNDANT_PATTERN;
   7
   8 pub(super) fn check(cx: &EarlyContext<'_>, pat: &Pat) {
   9     if let PatKind::Ident(left, ident, Some(ref right)) = pat.kind {
  10         let left_binding = match left {
  11             BindingMode::ByRef(Mutability::Mut) => "ref mut ",
  12             BindingMode::ByRef(Mutability::Not) => "ref ",
  13             BindingMode::ByValue(..) => "",
  14         };
  15
  16         if let PatKind::Wild = right.kind {
  17             span_lint_and_sugg(
  18                 cx,
  19                 REDUNDANT_PATTERN,
  20                 pat.span,
  21                 &format!(
  22                     "the `{} @ _` pattern can be written as just `{}`",
  23                     ident.name, ident.name,
  24                 ),
  25                 "try",
  26                 format!("{}{}", left_binding, ident.name),
  27                 Applicability::MachineApplicable,
  28             );
  29         }
  30     }
  31 }