limit packed copy-out to non-generic Copy structs

src/test/ui/deriving-with-repr-packed.rs

@@ -0,0 +1,27 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![deny(safe_packed_borrows)]
+
+// check that deriving a non-Copy packed struct is an error.
+#[derive(Copy, Clone, PartialEq, Eq)]
+#[repr(packed)]
+pub struct Foo<T>(T, T, T);
+//~^ ERROR #[derive] can't be used
+//~| hard error
+//~^^^ ERROR #[derive] can't be used
+//~| hard error
+#[derive(PartialEq, Eq)]
+#[repr(packed)]
+pub struct Bar(u32, u32, u32);
+//~^ ERROR #[derive] can't be used
+//~| hard error
+
+fn main() {}

src/test/ui/deriving-with-repr-packed.stderr

@@ -0,0 +1,34 @@
+error: #[derive] can't be used on a #[repr(packed)] struct with type parameters (error E0133)
+  --> $DIR/deriving-with-repr-packed.rs:16:19
+   |
+16 | pub struct Foo<T>(T, T, T);
+   |                   ^^
+   |
+note: lint level defined here
+  --> $DIR/deriving-with-repr-packed.rs:11:9
+   |
+11 | #![deny(safe_packed_borrows)]
+   |         ^^^^^^^^^^^^^^^^^^^
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #46043 <https://github.com/rust-lang/rust/issues/46043>
+
+error: #[derive] can't be used on a #[repr(packed)] struct with type parameters (error E0133)
+  --> $DIR/deriving-with-repr-packed.rs:16:19
+   |
+16 | pub struct Foo<T>(T, T, T);
+   |                   ^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #46043 <https://github.com/rust-lang/rust/issues/46043>
+
+error: #[derive] can't be used on a non-Copy #[repr(packed)] struct (error E0133)
+  --> $DIR/deriving-with-repr-packed.rs:23:16
+   |
+23 | pub struct Bar(u32, u32, u32);
+   |                ^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #46043 <https://github.com/rust-lang/rust/issues/46043>
+
+error: aborting due to 5 previous errors
+