You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: reference.rs
    path of file: ./repos/rust-clippy/clippy_lints/src
    
    the code of the file until where you have to start completion: use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::source::{snippet_opt, snippet_with_applicability};
use rustc_ast::ast::{Expr, ExprKind, Mutability, UnOp};
use rustc_errors::Applicability;
use rustc_lint::{EarlyContext, EarlyLintPass};
use rustc_session::declare_lint_pass;
use rustc_span::BytePos;

declare_clippy_lint! {
    /// ### What it does
    /// Checks for usage of `*&` and `*&mut` in expressions.
    ///
    /// ### Why is this bad?
    /// Immediately dereferencing a reference is no-op and
    /// makes the code less clear.
    ///
    /// ### Known problems
    /// Multiple dereference/addrof pairs are not handled so
    /// the suggested fix for `x = **&&y` is `x = *&y`, which is still incorrect.
    ///
    /// ### Example
    /// ```rust,ignore
    /// let a = f(*&mut b);
    /// let c = *&d;
    /// ```
    ///
    /// Use instead:
    /// ```rust,ignore
    /// let a = f(b);
    /// let c = d;
    /// ```
    #[clippy::version = "pre 1.29.0"]
    pub DEREF_ADDROF,
    complexity,
    "use of `*&` or `*&mut` in an expression"
}

declare_lint_pass!(DerefAddrOf => [DEREF_ADDROF]);

fn without_parens(mut e: &Expr) -> &Expr {
    while let Exp
    
    fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &Expr) {
        if let ExprKind::Unary(UnOp::Deref, ref deref_target) = e.kind
            && let ExprKind::AddrOf(_, ref mutability, ref addrof_target) = without_parens(deref_target).kind
            && deref_target.span.eq_ctxt(e.span)
            && !addrof_target.span.from_expansion()
        {
            let mut applicability = Applicability::MachineApplicable;
            let sugg = if e.span.from_expansion() {
                if let Some(macro_source) = snippet_opt(cx, e.span) {
                    // Remove leading whitespace from the given span
                    // e.g: ` $visitor` turns into `$visitor`
                    let trim_leading_whitespaces = |span| {
                        snippet_opt(cx, span)
                            .and_then(|snip| {
                                #[expect(clippy::cast_possible_truncation)]
                                snip.find(|c: char| !c.is_whitespace())
                                    .map(|pos| span.lo() + BytePos(pos as u32))
                            })
                            .map_or(span, |start_no_whitespace| e.span.with_lo(start_no_whitespace))
                    };

                    let mut generate_snippet = |pattern: &str| {
                        #[expect(clippy::cast_possible_truncation)]
                        macro_source.rfind(pattern).map(|pattern_pos| {
                            let rpos = pattern_pos + pattern.len();
                            let span_after_ref = e.span.with_lo(BytePos(e.span.lo().0 + rpos as u32));
                            let span = trim_leading_whitespaces(span_after_ref);
                            snippet_with_applicability(cx, span, "_", &mut applicability)
                        })
                    };

                    if *mutability == Mutability::Mut {
                        generate_snippet("mut")
                    } else {
                        generate_snippet("&")
                    }
                } else {
                    Some(snippet_with_applicability(cx, e.span, "_", &mut applicability))
                }
            } else {
                Some(snippet_with_applicability(
                    cx,
                    addrof_target.span,
                    "_",
                    &mut applicability,
                ))
            };
            if let Some(sugg) = sugg {
                span_lint_and_sugg(
                    cx,
                    DEREF_ADDROF,
                    e.span,
                    "immediately dereferencing a reference",
                    "try",
                    sugg.to_string(),
                    applicability,
                );
            }
        }
    }