From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:02:58 +0200
Subject: Adding upstream version 1.64.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../rustc_error_codes/src/error_codes/E0573.md     | 71 ++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 compiler/rustc_error_codes/src/error_codes/E0573.md

(limited to 'compiler/rustc_error_codes/src/error_codes/E0573.md')

diff --git a/compiler/rustc_error_codes/src/error_codes/E0573.md b/compiler/rustc_error_codes/src/error_codes/E0573.md
new file mode 100644
index 000000000..6021ed0ef
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0573.md
@@ -0,0 +1,71 @@
+Something other than a type has been used when one was expected.
+
+Erroneous code examples:
+
+```compile_fail,E0573
+enum Dragon {
+    Born,
+}
+
+fn oblivion() -> Dragon::Born { // error!
+    Dragon::Born
+}
+
+const HOBBIT: u32 = 2;
+impl HOBBIT {} // error!
+
+enum Wizard {
+    Gandalf,
+    Saruman,
+}
+
+trait Isengard {
+    fn wizard(_: Wizard::Saruman); // error!
+}
+```
+
+In all these errors, a type was expected. For example, in the first error, if
+we want to return the `Born` variant from the `Dragon` enum, we must set the
+function to return the enum and not its variant:
+
+```
+enum Dragon {
+    Born,
+}
+
+fn oblivion() -> Dragon { // ok!
+    Dragon::Born
+}
+```
+
+In the second error, you can't implement something on an item, only on types.
+We would need to create a new type if we wanted to do something similar:
+
+```
+struct Hobbit(u32); // we create a new type
+
+const HOBBIT: Hobbit = Hobbit(2);
+impl Hobbit {} // ok!
+```
+
+In the third case, we tried to only expect one variant of the `Wizard` enum,
+which is not possible. To make this work, we need to using pattern matching
+over the `Wizard` enum:
+
+```
+enum Wizard {
+    Gandalf,
+    Saruman,
+}
+
+trait Isengard {
+    fn wizard(w: Wizard) { // ok!
+        match w {
+            Wizard::Saruman => {
+                // do something
+            }
+            _ => {} // ignore everything else
+        }
+    }
+}
+```
-- 
cgit v1.2.3