+use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_then};
+use clippy_utils::source::snippet;
+use clippy_utils::sugg::Sugg;
+use core::iter::once;
+use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability, Pat, PatKind};
+use rustc_lint::LateContext;
+
+use super::MATCH_REF_PATS;
+
+pub(crate) fn check<'a, 'b, I>(cx: &LateContext<'_>, ex: &Expr<'_>, pats: I, expr: &Expr<'_>)
+where
+ 'b: 'a,
+ I: Clone + Iterator<Item = &'a Pat<'b>>,
+{
+ if !has_multiple_ref_pats(pats.clone()) {
+ return;
+ }
+
+ let (first_sugg, msg, title);
+ let span = ex.span.source_callsite();
+ if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner) = ex.kind {
+ first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string()));
+ msg = "try";
+ title = "you don't need to add `&` to both the expression and the patterns";
+ } else {
+ first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string()));
+ msg = "instead of prefixing all patterns with `&`, you can dereference the expression";
+ title = "you don't need to add `&` to all patterns";
+ }
+
+ let remaining_suggs = pats.filter_map(|pat| {
+ if let PatKind::Ref(refp, _) = pat.kind {
+ Some((pat.span, snippet(cx, refp.span, "..").to_string()))
+ } else {
+ None
+ }
+ });
+
+ span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |diag| {
+ if !expr.span.from_expansion() {
+ multispan_sugg(diag, msg, first_sugg.chain(remaining_suggs));
+ }
+ });
+}
+
+fn has_multiple_ref_pats<'a, 'b, I>(pats: I) -> bool
+where
+ 'b: 'a,
+ I: Iterator<Item = &'a Pat<'b>>,
+{
+ let mut ref_count = 0;
+ for opt in pats.map(|pat| match pat.kind {
+ PatKind::Ref(..) => Some(true), // &-patterns
+ PatKind::Wild => Some(false), // an "anything" wildcard is also fine
+ _ => None, // any other pattern is not fine
+ }) {
+ if let Some(inner) = opt {
+ if inner {
+ ref_count += 1;
+ }
+ } else {
+ return false;
+ }
+ }
+ ref_count > 1
+}