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Clarify that 0 is a valid multiple of a type's alignment #1260

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merged 1 commit into from
Sep 10, 2022

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@joshlf joshlf commented Sep 4, 2022

The reference currently states that "[t]he size of a value is always a multiple of its alignment." This might be taken to imply that a type's size is greater than or equal to its alignment. This commit clarifies that 0 is a valid multiple; zero-sized types have 0 size and nonzero alignment.

The reference currently states that "[t]he size of a value is always a multiple of its alignment." This might be taken to imply that a type's size is greater than or equal to its alignment. This commit clarifies that 0 is a valid multiple; zero-sized types have 0 size and nonzero alignment.
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Thanks! Yea, it does seem like 0 is considered a factor. I've always felt this paragraph is a bit awkward in how it uses array layout to define size.

I'm going to go ahead and merge even though I'm not 100% confident in the wording here. If someone wants to rework it to be clearer, feel free to follow up.

@ehuss ehuss merged commit 18d13e7 into rust-lang:master Sep 10, 2022
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Sep 21, 2022
Update books

## nomicon

1 commits in d880e6ac2acf133dce640da24b9fb692844f02d4..f53bfa056929217870a5d2df1366d2e7ba35096d
2022-08-24 12:42:34 -0700 to 2022-09-05 07:19:02 -0700
- Small typo (rust-lang/nomicon#379)

## reference

9 commits in f62e93c28323ed9637d0a205a0c256498674a509..a7cdac33ca7356ad49d5c2b5e2c5010889b33eee
2022-08-28 10:01:28 -0700 to 2022-09-19 17:39:58 -0700
- Clarify wording for references. (rust-lang/reference#1223)
- Update Unicode reference to match rustc implementation (rust-lang/reference#1271)
- Add documentation for raw-dylib and link_ordinal (rust-lang/reference#1244)
- Specify guarantees for repr(rust) structs (rust-lang/reference#1152)
- Classify AsyncBlockExpression as ExpressionWithoutBlock (rust-lang/reference#1268)
- Update closure-expr.md (rust-lang/reference#1269)
- Clarify that 0 is a valid multiple of a type's alignment (rust-lang/reference#1260)
- Remove `ne` from derive example (rust-lang/reference#1264)
- Clarify reference on async blocks (rust-lang/reference#1262)

## book

6 commits in 0a5421ceb238357b3634fb75234eba4d1dad643c..f1e5ad844d0c61738006cdef26227beeb136948e
2022-08-28 19:51:04 -0400 to 2022-09-19 09:48:21 -0400
- Fix punctuation in ch05-02
- Ownership move chapter link fix
- Wrong listing number
- Reword text around box
- `Box<T>` instead of "box"
- Update Clippy output in Appendix D

## rust-by-example

2 commits in 03301f8ae55fa6f20f7ea152a517598e6db2cdb7..767a6bd9727a596d7cfdbaeee475e65b2670ea3a
2022-08-14 08:51:44 -0300 to 2022-09-14 09:17:18 -0300
- struct_visibility.md:  Remove unneeded '#[allow(dead_code)]' (rust-lang/rust-by-example#1609)
- Fix assorted typos (rust-lang/rust-by-example#1601)

## rustc-dev-guide

15 commits in 04892c1a6fc145602ac7367945fda9d4ee83c9fb..f587d6e7cddeaa3cf0a33ec1e368df1a408fa0aa
2022-08-29 20:07:51 +0200 to 2022-09-20 07:43:59 +0900
- Update stability guide to use CURRENT_RUSTC_VERSION (rust-lang/rustc-dev-guide#1468)
- Add a note about building `rust-analyzer-proc-macro-srv` (rust-lang/rustc-dev-guide#1467)
- Link from "implementing to new features" to mcp.md (rust-lang/rustc-dev-guide#1465)
- remove stray **
- Explain the new valtree system for type level constants. (rust-lang/rustc-dev-guide#1097)
- fix typos and formatting
- Say "bootstrap" instead of "rustbuild"; the latter is not explained anywhere and is not much more clear.
- Rewrite the section on passing flags to subcommands
- Remove the diagram of all outputs generated by x.py
- "symbol names" => ABI
- Add symbol-addition to the how-to for new features (rust-lang/rustc-dev-guide#1457)
- Fix typo (rust-lang/rustc-dev-guide#1459)
- Document multipart_suggestion derive on SessionSubdiagnostic
- Add reference for updating Windows PATH and fix typo
- Update for removal of RLS (rust-lang/rustc-dev-guide#1450)

## embedded-book

1 commits in befe6840874311635c417cf731377f07234ee373..4ce51cb7441a6f02b5bf9b07b2eb755c21ab7954
2022-07-25 07:51:14 +0000 to 2022-09-15 08:53:09 +0000
- Create CITATION.bib (as per rust-embedded/book#327)  (rust-embedded/book#329)
JohnTitor added a commit to JohnTitor/rust that referenced this pull request Sep 22, 2022
Update books

## nomicon

1 commits in d880e6ac2acf133dce640da24b9fb692844f02d4..f53bfa056929217870a5d2df1366d2e7ba35096d
2022-08-24 12:42:34 -0700 to 2022-09-05 07:19:02 -0700
- Small typo (rust-lang/nomicon#379)

## reference

9 commits in f62e93c28323ed9637d0a205a0c256498674a509..a7cdac33ca7356ad49d5c2b5e2c5010889b33eee
2022-08-28 10:01:28 -0700 to 2022-09-19 17:39:58 -0700
- Clarify wording for references. (rust-lang/reference#1223)
- Update Unicode reference to match rustc implementation (rust-lang/reference#1271)
- Add documentation for raw-dylib and link_ordinal (rust-lang/reference#1244)
- Specify guarantees for repr(rust) structs (rust-lang/reference#1152)
- Classify AsyncBlockExpression as ExpressionWithoutBlock (rust-lang/reference#1268)
- Update closure-expr.md (rust-lang/reference#1269)
- Clarify that 0 is a valid multiple of a type's alignment (rust-lang/reference#1260)
- Remove `ne` from derive example (rust-lang/reference#1264)
- Clarify reference on async blocks (rust-lang/reference#1262)

## book

6 commits in 0a5421ceb238357b3634fb75234eba4d1dad643c..f1e5ad844d0c61738006cdef26227beeb136948e
2022-08-28 19:51:04 -0400 to 2022-09-19 09:48:21 -0400
- Fix punctuation in ch05-02
- Ownership move chapter link fix
- Wrong listing number
- Reword text around box
- `Box<T>` instead of "box"
- Update Clippy output in Appendix D

## rust-by-example

2 commits in 03301f8ae55fa6f20f7ea152a517598e6db2cdb7..767a6bd9727a596d7cfdbaeee475e65b2670ea3a
2022-08-14 08:51:44 -0300 to 2022-09-14 09:17:18 -0300
- struct_visibility.md:  Remove unneeded '#[allow(dead_code)]' (rust-lang/rust-by-example#1609)
- Fix assorted typos (rust-lang/rust-by-example#1601)

## rustc-dev-guide

15 commits in 04892c1a6fc145602ac7367945fda9d4ee83c9fb..f587d6e7cddeaa3cf0a33ec1e368df1a408fa0aa
2022-08-29 20:07:51 +0200 to 2022-09-20 07:43:59 +0900
- Update stability guide to use CURRENT_RUSTC_VERSION (rust-lang/rustc-dev-guide#1468)
- Add a note about building `rust-analyzer-proc-macro-srv` (rust-lang/rustc-dev-guide#1467)
- Link from "implementing to new features" to mcp.md (rust-lang/rustc-dev-guide#1465)
- remove stray **
- Explain the new valtree system for type level constants. (rust-lang/rustc-dev-guide#1097)
- fix typos and formatting
- Say "bootstrap" instead of "rustbuild"; the latter is not explained anywhere and is not much more clear.
- Rewrite the section on passing flags to subcommands
- Remove the diagram of all outputs generated by x.py
- "symbol names" => ABI
- Add symbol-addition to the how-to for new features (rust-lang/rustc-dev-guide#1457)
- Fix typo (rust-lang/rustc-dev-guide#1459)
- Document multipart_suggestion derive on SessionSubdiagnostic
- Add reference for updating Windows PATH and fix typo
- Update for removal of RLS (rust-lang/rustc-dev-guide#1450)

## embedded-book

1 commits in befe6840874311635c417cf731377f07234ee373..4ce51cb7441a6f02b5bf9b07b2eb755c21ab7954
2022-07-25 07:51:14 +0000 to 2022-09-15 08:53:09 +0000
- Create CITATION.bib (as per rust-embedded/book#327)  (rust-embedded/book#329)
@joshlf joshlf deleted the patch-2 branch November 6, 2022 19:37
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2 participants