3 files changed, 42 insertions, 1 deletions
diff --git a/tests/ui/entry.fixed b/tests/ui/entry.fixed
index 71ec13f4610..abdfae2a3e1 100644
--- a/tests/ui/entry.fixed
+++ b/tests/ui/entry.fixed
@@ -176,4 +176,14 @@ pub fn issue_11935() {
     }
 }
 
+fn issue12489(map: &mut HashMap<u64, u64>) -> Option<()> {
+    if let std::collections::hash_map::Entry::Vacant(e) = map.entry(1) {
+        let Some(1) = Some(2) else {
+            return None;
+        };
+        e.insert(42);
+    }
+    Some(())
+}
+
 fn main() {}
diff --git a/tests/ui/entry.rs b/tests/ui/entry.rs
index 86092b7c055..7774f99a2a2 100644
--- a/tests/ui/entry.rs
+++ b/tests/ui/entry.rs
@@ -180,4 +180,14 @@ pub fn issue_11935() {
     }
 }
 
+fn issue12489(map: &mut HashMap<u64, u64>) -> Option<()> {
+    if !map.contains_key(&1) {
+        let Some(1) = Some(2) else {
+            return None;
+        };
+        map.insert(1, 42);
+    }
+    Some(())
+}
+
 fn main() {}
diff --git a/tests/ui/entry.stderr b/tests/ui/entry.stderr
index ef4c36bcf54..fb467676606 100644
--- a/tests/ui/entry.stderr
+++ b/tests/ui/entry.stderr
@@ -214,5 +214,26 @@ LL +         v
 LL +     });
    |
 
-error: aborting due to 10 previous errors
+error: usage of `contains_key` followed by `insert` on a `HashMap`
+  --> tests/ui/entry.rs:184:5
+   |
+LL | /     if !map.contains_key(&1) {
+LL | |         let Some(1) = Some(2) else {
+LL | |             return None;
+LL | |         };
+LL | |         map.insert(1, 42);
+LL | |     }
+   | |_____^
+   |
+help: try
+   |
+LL ~     if let std::collections::hash_map::Entry::Vacant(e) = map.entry(1) {
+LL +         let Some(1) = Some(2) else {
+LL +             return None;
+LL +         };
+LL +         e.insert(42);
+LL +     }
+   |
+
+error: aborting due to 11 previous errors