From 536114c8572357db28c349c5ec1e822c7c0e2267 Mon Sep 17 00:00:00 2001
From: lengyijun <sjtu5140809011@gmail.com>
Date: Sun, 15 Oct 2023 08:40:47 +0800
Subject: [PATCH] [`ignored_unit_patterns`]: check &(), &&(), ...

---
 clippy_lints/src/ignored_unit_patterns.rs |  2 +-
 tests/ui/ignored_unit_patterns.fixed      | 16 ++++++++++++++++
 tests/ui/ignored_unit_patterns.rs         | 16 ++++++++++++++++
 tests/ui/ignored_unit_patterns.stderr     | 14 +++++++++++++-
 4 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/clippy_lints/src/ignored_unit_patterns.rs b/clippy_lints/src/ignored_unit_patterns.rs
index ef2a66d4a20..3e77bededcd 100644
--- a/clippy_lints/src/ignored_unit_patterns.rs
+++ b/clippy_lints/src/ignored_unit_patterns.rs
@@ -52,7 +52,7 @@ impl<'tcx> LateLintPass<'tcx> for IgnoredUnitPatterns {
             },
             _ => {},
         }
-        if matches!(pat.kind, PatKind::Wild) && cx.typeck_results().pat_ty(pat).is_unit() {
+        if matches!(pat.kind, PatKind::Wild) && cx.typeck_results().pat_ty(pat).peel_refs().is_unit() {
             span_lint_and_sugg(
                 cx,
                 IGNORED_UNIT_PATTERNS,
diff --git a/tests/ui/ignored_unit_patterns.fixed b/tests/ui/ignored_unit_patterns.fixed
index 15eaf1f659a..707a0e76e4e 100644
--- a/tests/ui/ignored_unit_patterns.fixed
+++ b/tests/ui/ignored_unit_patterns.fixed
@@ -38,3 +38,19 @@ pub fn moo(_: ()) {
     let _: () = foo().unwrap();
     let _: () = ();
 }
+
+fn test_unit_ref_1() {
+    let x: (usize, &&&&&()) = (1, &&&&&&());
+    match x {
+        (1, ()) => unimplemented!(),
+        //~^ ERROR: matching over `()` is more explicit
+        _ => unimplemented!(),
+    };
+}
+
+fn test_unit_ref_2(v: &[(usize, ())]) {
+    for (x, ()) in v {
+        //~^ ERROR: matching over `()` is more explicit
+        let _ = x;
+    }
+}
diff --git a/tests/ui/ignored_unit_patterns.rs b/tests/ui/ignored_unit_patterns.rs
index 9cac3a440ab..544f2b8f692 100644
--- a/tests/ui/ignored_unit_patterns.rs
+++ b/tests/ui/ignored_unit_patterns.rs
@@ -38,3 +38,19 @@ pub fn moo(_: ()) {
     let _: () = foo().unwrap();
     let _: () = ();
 }
+
+fn test_unit_ref_1() {
+    let x: (usize, &&&&&()) = (1, &&&&&&());
+    match x {
+        (1, _) => unimplemented!(),
+        //~^ ERROR: matching over `()` is more explicit
+        _ => unimplemented!(),
+    };
+}
+
+fn test_unit_ref_2(v: &[(usize, ())]) {
+    for (x, _) in v {
+        //~^ ERROR: matching over `()` is more explicit
+        let _ = x;
+    }
+}
diff --git a/tests/ui/ignored_unit_patterns.stderr b/tests/ui/ignored_unit_patterns.stderr
index cac01a87dba..05c8f281e55 100644
--- a/tests/ui/ignored_unit_patterns.stderr
+++ b/tests/ui/ignored_unit_patterns.stderr
@@ -43,5 +43,17 @@ error: matching over `()` is more explicit
 LL |     let _ = foo().unwrap();
    |         ^ help: use `()` instead of `_`: `()`
 
-error: aborting due to 7 previous errors
+error: matching over `()` is more explicit
+  --> $DIR/ignored_unit_patterns.rs:45:13
+   |
+LL |         (1, _) => unimplemented!(),
+   |             ^ help: use `()` instead of `_`: `()`
+
+error: matching over `()` is more explicit
+  --> $DIR/ignored_unit_patterns.rs:52:13
+   |
+LL |     for (x, _) in v {
+   |             ^ help: use `()` instead of `_`: `()`
+
+error: aborting due to 9 previous errors