Update tests/ui/pattern/issue-115599.rs

tests/ui/pattern/issue-115599.rs

@@ -1,7 +1,14 @@
-const CONST_STRING: String = String::new();
+//! Test that a type with derived (Partial)Eq, and thus Structural(Partial)Eq
+//! that is a newtype over a type without Structural(Partial)Eq correctly errors.
+
+// `String` in the stdlib no longer derives these traits, so make our own here.
+#[derive(PartialEq, Eq, PartialOrd, Ord)]
+struct String(Vec<u8>);
+
+const CONST_STRING: String = String(Vec::new());
 
 fn main() {
-    let empty_str = String::from("");
+    let empty_str = String(Vec::from(&[]));
     if let CONST_STRING = empty_str {}
     //~^ ERROR to use a constant of type `Vec<u8>` in a pattern, `Vec<u8>` must be annotated with `#[derive(PartialEq)]`
 }

tests/ui/pattern/issue-115599.stderr

@@ -1,5 +1,5 @@
-error: to use a constant of type `String` in a pattern, `String` must be annotated with `#[derive(PartialEq)]`
-  --> $DIR/issue-115599.rs:5:12
+error: to use a constant of type `Vec<u8>` in a pattern, `Vec<u8>` must be annotated with `#[derive(PartialEq)]`
+  --> $DIR/issue-115599.rs:12:12
    |
 LL |     if let CONST_STRING = empty_str {}
    |            ^^^^^^^^^^^^