Add a test checking the output of builtin derives.

src/test/ui/deriving/deriving-all-codegen.rs

@@ -0,0 +1,63 @@
+// check-pass
+// compile-flags: -Zunpretty=expanded
+// edition:2021
+//
+// This test checks the code generated for all[*] the builtin derivable traits
+// on a variety of structs and enums. It protects against accidental changes to
+// the generated code, and makes deliberate changes to the generated code
+// easier to review.
+//
+// [*] It excludes `Copy` in some cases, because that changes the code
+// generated for `Clone`.
+//
+// [*] It excludes `RustcEncodable` and `RustDecodable`, which are obsolete and
+// also require the `rustc_serialize` crate.
+
+#![crate_type = "lib"]
+#![allow(dead_code)]
+#![allow(deprecated)]
+
+// Empty struct.
+#[derive(Clone, Copy, Debug, Default, Hash, PartialEq, Eq, PartialOrd, Ord)]
+struct Empty;
+
+// A basic struct.
+#[derive(Clone, Copy, Debug, Default, Hash, PartialEq, Eq, PartialOrd, Ord)]
+struct Point {
+    x: u32,
+    y: u32,
+}
+
+// A long struct.
+#[derive(Clone, Debug, Default, Hash, PartialEq, Eq, PartialOrd, Ord)]
+struct Big {
+    b1: u32, b2: u32, b3: u32, b4: u32, b5: u32, b6: u32, b7: u32, b8:u32,
+}
+
+// A C-like, fieldless enum.
+#[derive(Clone, Copy, Debug, Default, Hash, PartialEq, Eq, PartialOrd, Ord)]
+enum Fieldless {
+    #[default]
+    A,
+    B,
+    C,
+}
+
+// An enum with multiple fieldless and fielded variants.
+#[derive(Clone, Copy, Debug, Default, Hash, PartialEq, Eq, PartialOrd, Ord)]
+enum Mixed {
+    #[default]
+    P,
+    Q,
+    R(u32),
+    S { d1: u32, d2: u32 },
+}
+
+// An enum with no fieldless variants. Note that `Default` cannot be derived
+// for this enum.
+#[derive(Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
+enum Fielded {
+    X(u32),
+    Y(bool),
+    Z(Option<i32>),
+}