Add 80531 (#602)

Issue: rust-lang/rust#80531

Author: light4

ices/80531.rs

@@ -0,0 +1,14 @@
+#![crate_type = "lib"]
+
+enum ConstGenericEnum<const N: usize> {
+    Foo([i32; N]),
+    Bar,
+}
+
+fn foo<const N: usize>(val: &ConstGenericEnum<N>) {
+    if let ConstGenericEnum::<N>::Foo(field, ..) = val {
+        todo!()
+    } else {
+        todo!()
+    }
+}