Explain more in depth what early and late bound generic parameters are #1732
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| Here, the type `(Self, T, U)` would be `($0, $1, $2)`, where `$N` means a | ||
| [`ParamTy`] with the index of `N`. | ||
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| In rustc, the [`Generics`] structure carries this information. So the |
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May be worth explicitly stating that Generics can be used to map from this index to a parameter definition.
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probably but also i dont really want to in this PR
| presence by a [`Binder`] type. The [`Binder`] doesn't know how many variables | ||
| there are at that binding level. This can only be determined by walking the | ||
| type itself and collecting them. So a type like `for<'a, 'b> ('a, 'b)` would be | ||
| `for (^0.a, ^0.b)`. Here, we just write `for` because we don't know the names |
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Worth showing an example with a debruijn index > 0?
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yes but not in this PR because I don't really want to touch this too much until we sort out the naming of RegionKind's variants
Co-authored-by: Michael Goulet <michael@errs.io>
Co-authored-by: Michael Goulet <michael@errs.io>
compiler-errors
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Update books ## rust-lang/reference 7 commits in 1ea0178266b3f3f613b0fabdaf16a83961c99cdb..9cd5c5a6ccbd4c07c65ab5c69a53286280308c95 2023-07-29 22:29:51 UTC to 2023-07-16 20:12:46 UTC - Fix merge queue building twice. (rust-lang/reference#1383) - Clarify UB around immutability & mutation (rust-lang/reference#1385) - mention the extra const UB (rust-lang/reference#1273) - Operator expressions: make the note about division by zero clearer. (rust-lang/reference#1384) - Make unsafe keyword docs less confusing (rust-lang/reference#1379) - Say that division by zero for primitive types panics (rust-lang/reference#1382) - Add CI trigger for merge queues. (rust-lang/reference#1381) ## rust-lang/rust-by-example 3 commits in 8a87926a985ce32ca1fad1be4008ee161a0b91eb..07e0df2f006e59d171c6bf3cafa9d61dbeb520d8 2023-07-24 11:37:55 UTC to 2023-07-24 11:35:36 UTC - Added attribute unused_labels - fixed warning. (rust-lang/rust-by-example#1729) - more explanation about panic (rust-lang/rust-by-example#1728) - chore: add the portuguese version of this project to `readme.md` (rust-lang/rust-by-example#1727) ## rust-lang/rustc-dev-guide 26 commits in b5a12d95e32ae53791cc6ab44417774667ed2ac6..24eebb6df96d037aad285e4f7793bd0393a66878 2023-07-30 11:23:23 UTC to 2023-07-11 06:02:34 UTC - fix(name-resolution): remove unnecessary closing paranthesis (rust-lang/rustc-dev-guide#1760) - fix(macro-expansion.md): fix the article `an` to `a` (rust-lang/rustc-dev-guide#1759) - fix(serialization.md): fix the name of a derive macro (rust-lang/rustc-dev-guide#1756) - fix(serialization.md): add a necessary plural suffix (rust-lang/rustc-dev-guide#1757) - fix(salsa.md): add punctuation to prevent confusion (rust-lang/rustc-dev-guide#1754) - fix(salsa.md): remove duplicate "To Be" verb (rust-lang/rustc-dev-guide#1755) - feat(fuzzing.md): make `halfempty` word a link (rust-lang/rustc-dev-guide#1750) - fix(about.md): use `a` instead of `an` (rust-lang/rustc-dev-guide#1751) - refactor(git.md): make git-scm links clickable (rust-lang/rustc-dev-guide#1747) - fix(walkthrough.md) add a comma operator to eliminate ambiguity (rust-lang/rustc-dev-guide#1749) - fix(git.md): remove a confusing end of sentence character (rust-lang/rustc-dev-guide#1748) - refactor(profiling/with_perf): remove a wrong to be verb (rust-lang/rustc-dev-guide#1746) - refactor(tests/headers): remove duplicate list item (rust-lang/rustc-dev-guide#1745) - refactor(test/headers.md): make the meaning more obvious (rust-lang/rustc-dev-guide#1744) - refactor(tests/ui): remove unnecessary duplicate word (rust-lang/rustc-dev-guide#1743) - refactor(compiletest): remove unnecessary duplicate word (rust-lang/rustc-dev-guide#1742) - generic_arguments.md: substs -> GenericArgs (rust-lang/rustc-dev-guide#1741) - fix(suggested): remove an unnecessary and confusing statement (rust-lang/rustc-dev-guide#1739) - fix(how-to-build-and-run): fix a typo ("fromer" -> "former") (rust-lang/rustc-dev-guide#1736) - fix(how-to-build-and-run): remove a wrong paragraph (rust-lang/rustc-dev-guide#1735) - coverage code has moved (rust-lang/rustc-dev-guide#1728) - linked issue is closed (rust-lang/rustc-dev-guide#1729) - remove duplicate reference in about-this-guide.md (rust-lang/rustc-dev-guide#1734) - Explain more in depth what early and late bound generic parameters are (rust-lang/rustc-dev-guide#1732) - add section for normalization with the new solver (rust-lang/rustc-dev-guide#1731) - Improve cleanup-crew.md with an example post (rust-lang/rustc-dev-guide#1730)
matthiaskrgr
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Aug 14, 2023
Update books ## rust-lang/book 3 commits in 668c64760b5c7ea654facb4ba5fe9faddfda27cc..72187f5cd0beaaa9c6f584156bcd88f921871e83 2023-08-04 14:42:07 UTC to 2023-08-03 13:36:44 UTC - redirects: change link for the `#![no_std]` tutorial (rust-lang/book#3705) - [chpt10.2] - Small wording changes (rust-lang/book#3724) - Improve sentence (rust-lang/book#3725) ## rust-embedded/book 1 commits in 1e5556dd1b864109985d5871616ae6b9164bcead..99ad2847b865e96d8ae7b333d3ee96963557e621 2023-08-11 06:31:04 UTC to 2023-08-11 06:31:04 UTC - Fix a small typo in qemu.md (rust-embedded/book#359) ## rust-lang/nomicon 1 commits in 302b995bcb24b70fd883980fd174738c3a10b705..388750b081c0893c275044d37203f97709e058ba 2023-08-10 21:15:21 UTC to 2023-08-10 21:15:21 UTC - Document thiscall abi (rust-lang/nomicon#311) ## rust-lang/reference 10 commits in 1ea0178266b3f3f613b0fabdaf16a83961c99cdb..d43038932adeb16ada80e206d4c073d851298101 2023-08-12 19:07:28 UTC to 2023-07-16 20:12:46 UTC - Document thiscall abi (rust-lang/reference#1092) - add section about implied bounds (rust-lang/reference#1261) - Clearly specify the `instruction_set` effects (rust-lang/reference#1307) - Fix merge queue building twice. (rust-lang/reference#1383) - Clarify UB around immutability & mutation (rust-lang/reference#1385) - mention the extra const UB (rust-lang/reference#1273) - Operator expressions: make the note about division by zero clearer. (rust-lang/reference#1384) - Make unsafe keyword docs less confusing (rust-lang/reference#1379) - Say that division by zero for primitive types panics (rust-lang/reference#1382) - Add CI trigger for merge queues. (rust-lang/reference#1381) ## rust-lang/rust-by-example 3 commits in 8a87926a985ce32ca1fad1be4008ee161a0b91eb..07e0df2f006e59d171c6bf3cafa9d61dbeb520d8 2023-07-24 11:37:55 UTC to 2023-07-24 11:35:36 UTC - Added attribute unused_labels - fixed warning. (rust-lang/rust-by-example#1729) - more explanation about panic (rust-lang/rust-by-example#1728) - chore: add the portuguese version of this project to `readme.md` (rust-lang/rust-by-example#1727) ## rust-lang/rustc-dev-guide 31 commits in b5a12d95e32ae53791cc6ab44417774667ed2ac6..b123ab4754127d822ffb38349ce0fbf561f1b2fd 2023-08-14 08:34:59 UTC to 2023-07-11 06:02:34 UTC - fix: stabilize debugger_visualizer (rust-lang/rustc-dev-guide#1766) - feat(part-5-intro): make "Part 5" obvious (rust-lang/rustc-dev-guide#1753) - Update from `#[warn_]` to `#[warning]` diagnostic attributes (rust-lang/rustc-dev-guide#1765) - Add RPITIT documentation (rust-lang/rustc-dev-guide#1764) - fix(visitor.md): fix a type name in a code sample (rust-lang/rustc-dev-guide#1762) - fix(name-resolution): remove unnecessary closing paranthesis (rust-lang/rustc-dev-guide#1760) - fix(macro-expansion.md): fix the article `an` to `a` (rust-lang/rustc-dev-guide#1759) - fix(serialization.md): fix the name of a derive macro (rust-lang/rustc-dev-guide#1756) - fix(serialization.md): add a necessary plural suffix (rust-lang/rustc-dev-guide#1757) - fix(salsa.md): add punctuation to prevent confusion (rust-lang/rustc-dev-guide#1754) - fix(salsa.md): remove duplicate "To Be" verb (rust-lang/rustc-dev-guide#1755) - feat(fuzzing.md): make `halfempty` word a link (rust-lang/rustc-dev-guide#1750) - fix(about.md): use `a` instead of `an` (rust-lang/rustc-dev-guide#1751) - refactor(git.md): make git-scm links clickable (rust-lang/rustc-dev-guide#1747) - fix(walkthrough.md) add a comma operator to eliminate ambiguity (rust-lang/rustc-dev-guide#1749) - fix(git.md): remove a confusing end of sentence character (rust-lang/rustc-dev-guide#1748) - refactor(profiling/with_perf): remove a wrong to be verb (rust-lang/rustc-dev-guide#1746) - refactor(tests/headers): remove duplicate list item (rust-lang/rustc-dev-guide#1745) - refactor(test/headers.md): make the meaning more obvious (rust-lang/rustc-dev-guide#1744) - refactor(tests/ui): remove unnecessary duplicate word (rust-lang/rustc-dev-guide#1743) - refactor(compiletest): remove unnecessary duplicate word (rust-lang/rustc-dev-guide#1742) - generic_arguments.md: substs -> GenericArgs (rust-lang/rustc-dev-guide#1741) - fix(suggested): remove an unnecessary and confusing statement (rust-lang/rustc-dev-guide#1739) - fix(how-to-build-and-run): fix a typo ("fromer" -> "former") (rust-lang/rustc-dev-guide#1736) - fix(how-to-build-and-run): remove a wrong paragraph (rust-lang/rustc-dev-guide#1735) - coverage code has moved (rust-lang/rustc-dev-guide#1728) - linked issue is closed (rust-lang/rustc-dev-guide#1729) - remove duplicate reference in about-this-guide.md (rust-lang/rustc-dev-guide#1734) - Explain more in depth what early and late bound generic parameters are (rust-lang/rustc-dev-guide#1732) - add section for normalization with the new solver (rust-lang/rustc-dev-guide#1731) - Improve cleanup-crew.md with an example post (rust-lang/rustc-dev-guide#1730)
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I moved all the text about the
ty::representation of bound vars and generic parameters out into the subsection about thetymodule since I found it confusing to be put along side the explanation of what it means for a generic parameter to be early or late bound. To me there is a large difference between the two concepts and they do not deserve to be put together. (Ideally we would rewrite the bound-vars-and-params page and renameRegionKind::EarlyBound/LateBoundimo)This explanation of what early/late bound parameters are came from the deep dive that t-types did earlier this week, rust-lang/types-team#94. Thanks to @jyn514 also for looking over the document to give feedback before editing it to put in here.
cc @rust-lang/types