Fix `-Z print-type-sizes` for generators with discriminant field ordered first b...
source link: https://github.com/rust-lang/rust/pull/105623
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_ => Size::ZERO, |
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}; |
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if layout.fields.offset(tag_field) >= variant_size { |
It took me a while to understand why this change was correct, probably mostly because the variant_size variable is a little confusingly named. Maybe something like last_field_end would better?
Thinking about this a little more, what this code really wants to do is Actually no, that would be incorrect if the discriminant was at the end.variant_size.max(tag_end), maybe that would also make it simpler.
I'm not sure this is any clearer with the name last_field_end, because it really is the variant size (plus the upvars), modulo a hack to deal with needing to conditionally subtract one from the variant size depending on where the layout code chooses to put the tag.
Anyways, what I can do is leave a more detailed comment explaining why this is needed. This is probably still broken, but I don't know if it's worth taking much more time to fix.
This is true, all of this code is trying to fit generator layout into a normal layout shaped hole and it's not going great. The current name is fine too and yeah, spending too much time on this is probably not worth it.
But a quick comment would be nice.
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