Derive from any other trait only when deriving from Copy#2200
Derive from any other trait only when deriving from Copy#2200emilio merged 1 commit intorust-lang:masterfrom
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We should do this only when the struct is packed, or what am I missing? Otherwise it might break existing code gratuitously.
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@emilio Good point, it should be fixed now. |
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Thanks, looks good! I think we can simplify it slightly (given we always treat packed = None as false, but let me know if I'm missing something.
Looks good to me with that.
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It's impossible to #[derive] from any other trait when not deriving from Copy when using the newest Rust nightly. Any attempt to do that results in the following error: error: `#[derive]` can't be used on a `#[repr(packed)]` struct that does not derive Copy (error E0133) Fixes: rust-lang#2083 Signed-off-by: Michal Rostecki <[email protected]>
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Thank you for review! I like the idea with using just bool without Option, I applied it. |
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Thanks, this looks good for now. I think this might not be fully correct in the presence of a non-packed struct containing a packed struct... For that we probably need to track this properly in the CanDerive analysis.
That shouldn't be too hard, but doing this in the meantime is fine.
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@emilio Good call, I will try to address that in a separate PR |
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It's impossible to #[derive] from any other trait when not deriving from
Copy when using the newest Rust nightly. Any attempt to do that results
in the following error:
Fixes: #2083
Signed-off-by: Michal Rostecki [email protected]