Improve comments about type folding/visiting. #93758
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@BoxyUwU Thanks for the comments. I have addressed them and updated the code. |
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@bors r+ |
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📌 Commit 2e56c02 has been approved by |
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@bors rollup=always |
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…s, r=BoxyUwU Improve comments about type folding/visiting. I have found this code confusing for years. I've always roughly understood it, but never exactly. I just made my fourth(?) attempt and finally cracked it. This commit improves the comments. In particular, it explicitly describes how you can't do a custom fold/visit of any type; there are actually a handful of "types of interest" (e.g. `Ty`, `Predicate`, `Region`, `Const`) that can be custom folded/visted, and all other types just get a generic traversal. I think this was the part that eluded me on all my prior attempts at understanding. The commit also updates comments to account for some newer changes such as the fallible/infallible folding distinction, does some minor reorderings, and moves one `impl` to a better place. r? `@BoxyUwU`
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doctest failure #94065 (comment) |
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intra doc link checker stuff really ought to go into normal CI :( |
I have found this code confusing for years. I've always roughly understood it, but never exactly. I just made my fourth(?) attempt and finally cracked it. This commit improves the comments. In particular, it explicitly describes how you can't do a custom fold/visit of any type; there are actually a handful of "types of interest" (e.g. `Ty`, `Predicate`, `Region`, `Const`) that can be custom folded/visted, and all other types just get a generic traversal. I think this was the part that eluded me on all my prior attempts at understanding. The commit also updates comments to account for some newer changes such as the fallible/infallible folding distinction, does some minor reorderings, and moves one `impl` to a better place.
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I fixed the link bustage. @bors r=BoxyUwU |
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📌 Commit 94f0849 has been approved by |
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…askrgr Rollup of 9 pull requests Successful merges: - rust-lang#93337 (Update tracking issue numbers for inline assembly sub-features) - rust-lang#93758 (Improve comments about type folding/visiting.) - rust-lang#93780 (Generate list instead of div items in sidebar) - rust-lang#93976 (Add MAIN_SEPARATOR_STR) - rust-lang#94011 (Even more let_else adoptions) - rust-lang#94041 (Add a `try_collect()` helper method to `Iterator`) - rust-lang#94043 (Fix ICE when using Box<T, A> with pointer sized A) - rust-lang#94082 (Remove CFG_PLATFORM) - rust-lang#94085 (Clippy: Don't lint `needless_borrow` in method receiver positions) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
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I have found this code confusing for years. I've always roughly
understood it, but never exactly. I just made my fourth(?) attempt and
finally cracked it.
This commit improves the comments. In particular, it explicitly
describes how you can't do a custom fold/visit of any type; there are
actually a handful of "types of interest" (e.g.
Ty,Predicate,Region,Const) that can be custom folded/visted, and all other typesjust get a generic traversal. I think this was the part that eluded me
on all my prior attempts at understanding.
The commit also updates comments to account for some newer changes such
as the fallible/infallible folding distinction, does some minor
reorderings, and moves one
implto a better place.r? @BoxyUwU