Rollup merge of #104662 - nnethercote:tweak-deriving-for-packed-non-copy, r=jackh726

Streamline deriving on packed structs.

The current approach to field accesses in derived code:
- Normal case: `&self.0`
- In a packed struct that derives `Copy`: `&{self.0}`
- In a packed struct that doesn't derive `Copy`: `let Self(ref x) = *self`

The `let` pattern used in the third case is equivalent to the simpler field access in the first case. This commit changes the third case to use a field access.

The commit also combines two boolean arguments (`is_packed` and `always_copy`) into a single field (`copy_fields`) earlier, to save passing both around.

r? ``@jackh726``

0 files changed, 0 insertions, 0 deletions