From fff953f7c35cc156b40efc7fcb01db40003e223b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Sat, 28 Dec 2024 19:28:33 +0000
Subject: [PATCH] Add test ensuring correct suggestion for pattern dereference

```
error[E0308]: mismatched types
  --> $DIR/suggest-dereferencing-through-Deref.rs:13:16
   |
LL |         if let A::V1(v) = b {
   |                ^^^^^^^^   - this expression has type `&Box<A>`
   |                |
   |                expected `Box<A>`, found `A`
   |
   = note: expected struct `Box<A>`
                found enum `A`
help: consider dereferencing to access the inner value using the Deref trait
   |
LL |         if let A::V1(v) = &**b {
   |                           ~~~~

error[E0308]: mismatched types
  --> $DIR/suggest-dereferencing-through-Deref.rs:23:16
   |
LL |         if let A::V1(v) = *b {
   |                ^^^^^^^^   -- this expression has type `Box<A>`
   |                |
   |                expected `Box<A>`, found `A`
   |
   = note: expected struct `Box<A>`
                found enum `A`
help: consider dereferencing the boxed value
   |
LL |         if let A::V1(v) = **b {
   |                           ~~~
```

Fix #68628
---
 .../suggest-dereferencing-through-Deref.fixed | 29 ++++++++++++++++
 .../suggest-dereferencing-through-Deref.rs    | 29 ++++++++++++++++
 ...suggest-dereferencing-through-Deref.stderr | 33 +++++++++++++++++++
 3 files changed, 91 insertions(+)
 create mode 100644 tests/ui/pattern/suggest-dereferencing-through-Deref.fixed
 create mode 100644 tests/ui/pattern/suggest-dereferencing-through-Deref.rs
 create mode 100644 tests/ui/pattern/suggest-dereferencing-through-Deref.stderr

diff --git a/tests/ui/pattern/suggest-dereferencing-through-Deref.fixed b/tests/ui/pattern/suggest-dereferencing-through-Deref.fixed
new file mode 100644
index 0000000000000..a538929609d82
--- /dev/null
+++ b/tests/ui/pattern/suggest-dereferencing-through-Deref.fixed
@@ -0,0 +1,29 @@
+//@ run-rustfix
+#![allow(dead_code)]
+
+enum A {
+    V1(u8),
+    V2(u32),
+}
+
+fn foo() {
+    let a = Some(Box::new(A::V1(1u8)));
+    
+    if let Some(b) = a.as_ref() {
+        if let A::V1(v) = &**b { //~ ERROR mismatched types
+            println!("{:?}", v);
+        }
+    }
+}
+
+fn bar() {
+    let a = Some(Box::new(A::V1(1u8)));
+    
+    if let Some(b) = a.as_ref() {
+        if let A::V1(v) = **b { //~ ERROR mismatched types
+            println!("{:?}", v);
+        }
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/pattern/suggest-dereferencing-through-Deref.rs b/tests/ui/pattern/suggest-dereferencing-through-Deref.rs
new file mode 100644
index 0000000000000..c87fcf89497e3
--- /dev/null
+++ b/tests/ui/pattern/suggest-dereferencing-through-Deref.rs
@@ -0,0 +1,29 @@
+//@ run-rustfix
+#![allow(dead_code)]
+
+enum A {
+    V1(u8),
+    V2(u32),
+}
+
+fn foo() {
+    let a = Some(Box::new(A::V1(1u8)));
+    
+    if let Some(b) = a.as_ref() {
+        if let A::V1(v) = b { //~ ERROR mismatched types
+            println!("{:?}", v);
+        }
+    }
+}
+
+fn bar() {
+    let a = Some(Box::new(A::V1(1u8)));
+    
+    if let Some(b) = a.as_ref() {
+        if let A::V1(v) = *b { //~ ERROR mismatched types
+            println!("{:?}", v);
+        }
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/pattern/suggest-dereferencing-through-Deref.stderr b/tests/ui/pattern/suggest-dereferencing-through-Deref.stderr
new file mode 100644
index 0000000000000..61f79f30137f2
--- /dev/null
+++ b/tests/ui/pattern/suggest-dereferencing-through-Deref.stderr
@@ -0,0 +1,33 @@
+error[E0308]: mismatched types
+  --> $DIR/suggest-dereferencing-through-Deref.rs:13:16
+   |
+LL |         if let A::V1(v) = b {
+   |                ^^^^^^^^   - this expression has type `&Box<A>`
+   |                |
+   |                expected `Box<A>`, found `A`
+   |
+   = note: expected struct `Box<A>`
+                found enum `A`
+help: consider dereferencing to access the inner value using the Deref trait
+   |
+LL |         if let A::V1(v) = &**b {
+   |                           ~~~~
+
+error[E0308]: mismatched types
+  --> $DIR/suggest-dereferencing-through-Deref.rs:23:16
+   |
+LL |         if let A::V1(v) = *b {
+   |                ^^^^^^^^   -- this expression has type `Box<A>`
+   |                |
+   |                expected `Box<A>`, found `A`
+   |
+   = note: expected struct `Box<A>`
+                found enum `A`
+help: consider dereferencing the boxed value
+   |
+LL |         if let A::V1(v) = **b {
+   |                           ~~~
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.