1 files changed, 33 insertions, 0 deletions
diff --git a/src/test/ui/consts/issue-87046.rs b/src/test/ui/consts/issue-87046.rs
new file mode 100644
index 000000000..4b8f9f536
--- /dev/null
+++ b/src/test/ui/consts/issue-87046.rs
@@ -0,0 +1,33 @@
+// Regression test for the ICE described in #87046.
+
+#![crate_type="lib"]
+#![allow(unreachable_patterns)]
+
+#[derive(PartialEq, Eq)]
+#[repr(transparent)]
+pub struct Username(str);
+
+pub const ROOT_USER: &Username = Username::from_str("root");
+
+impl Username {
+    pub const fn from_str(raw: &str) -> &Self {
+        union Transmute<'a> {
+            raw: &'a str,
+            typed: &'a Username,
+        }
+
+        unsafe { Transmute { raw }.typed }
+    }
+
+    pub const fn as_str(&self) -> &str {
+        &self.0
+    }
+
+    pub fn is_root(&self) -> bool {
+        match self {
+            ROOT_USER => true,
+            //~^ ERROR: cannot use unsized non-slice type `Username` in constant patterns
+            _ => false,
+        }
+    }
+}