Auto merge of #66686 - Centril:rollup-07slyoo, r=Centril

Rollup of 5 pull requests

Successful merges:

 - #64856 (Scope format! temporaries)
 - #66411 (mem::forget docs: mention ManuallyDrop)
 - #66594 (Fix cycle when debug-printing opaque types)
 - #66641 (parser: recover on nested ADTs as enum variants)
 - #66659 (make `./x.py bench` again)

Failed merges:

r? @ghost

2 files changed, 34 insertions, 0 deletions

diff --git a/src/test/ui/enum/nested-enum.rs b/src/test/ui/enum/nested-enum.rs
new file mode 100644
index 00000000000..80957b8a14c
--- /dev/null
+++ b/src/test/ui/enum/nested-enum.rs
@@ -0,0 +1,8 @@
+enum Foo {
+    enum Bar { Baz }, //~ ERROR `enum` definition cannot be nested inside `enum`
+    struct Quux { field: u8 }, //~ ERROR `struct` definition cannot be nested inside `enum`
+    union Wibble { field: u8 }, //~ ERROR `union` definition cannot be nested inside `enum`
+    Bat,
+}
+
+fn main() { }
diff --git a/src/test/ui/enum/nested-enum.stderr b/src/test/ui/enum/nested-enum.stderr
new file mode 100644
index 00000000000..7d6f57e88a8
--- /dev/null
+++ b/src/test/ui/enum/nested-enum.stderr
@@ -0,0 +1,26 @@
+error: `enum` definition cannot be nested inside `enum`
+  --> $DIR/nested-enum.rs:2:5
+   |
+LL |     enum Bar { Baz },
+   |     ^^^^------------
+   |     |
+   |     help: consider creating a new `enum` definition instead of nesting
+
+error: `struct` definition cannot be nested inside `enum`
+  --> $DIR/nested-enum.rs:3:5
+   |
+LL |     struct Quux { field: u8 },
+   |     ^^^^^^-------------------
+   |     |
+   |     help: consider creating a new `struct` definition instead of nesting
+
+error: `union` definition cannot be nested inside `enum`
+  --> $DIR/nested-enum.rs:4:5
+   |
+LL |     union Wibble { field: u8 },
+   |     ^^^^^---------------------
+   |     |
+   |     help: consider creating a new `union` definition instead of nesting
+
+error: aborting due to 3 previous errors
+