2 files changed, 45 insertions, 0 deletions
diff --git a/src/test/ui/match/issue-12552.rs b/src/test/ui/match/issue-12552.rs
new file mode 100644
index 000000000..b7f71dd1c
--- /dev/null
+++ b/src/test/ui/match/issue-12552.rs
@@ -0,0 +1,11 @@
+// this code used to cause an ICE
+
+fn main() {
+  let t = Err(0);
+  match t {
+    Some(k) => match k { //~ ERROR mismatched types
+      a => println!("{}", a)
+    },
+    None => () //~ ERROR mismatched types
+  }
+}
diff --git a/src/test/ui/match/issue-12552.stderr b/src/test/ui/match/issue-12552.stderr
new file mode 100644
index 000000000..4b027eba2
--- /dev/null
+++ b/src/test/ui/match/issue-12552.stderr
@@ -0,0 +1,34 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-12552.rs:6:5
+   |
+LL |   match t {
+   |         - this expression has type `Result<_, {integer}>`
+LL |     Some(k) => match k {
+   |     ^^^^^^^ expected enum `Result`, found enum `Option`
+   |
+   = note: expected enum `Result<_, {integer}>`
+              found enum `Option<_>`
+help: try wrapping the pattern in `Ok`
+   |
+LL |     Ok(Some(k)) => match k {
+   |     +++       +
+
+error[E0308]: mismatched types
+  --> $DIR/issue-12552.rs:9:5
+   |
+LL |   match t {
+   |         - this expression has type `Result<_, {integer}>`
+...
+LL |     None => ()
+   |     ^^^^ expected enum `Result`, found enum `Option`
+   |
+   = note: expected enum `Result<_, {integer}>`
+              found enum `Option<_>`
+help: try wrapping the pattern in `Ok`
+   |
+LL |     Ok(None) => ()
+   |     +++    +
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.