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Bug in documentation #1628

Closed
Abhicodes-crypto opened this issue Oct 20, 2022 · 3 comments · Fixed by #1629 or rust-lang/rust#103543
Closed

Bug in documentation #1628

Abhicodes-crypto opened this issue Oct 20, 2022 · 3 comments · Fixed by #1629 or rust-lang/rust#103543

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@Abhicodes-crypto
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I was reading about Box from here https://doc.rust-lang.org/stable/rust-by-example/std/box.html
There is the below code in code snippet :

    // box size == pointer size
    println!("Boxed point occupies {} bytes on the heap",
             mem::size_of_val(&boxed_point));
    println!("Boxed rectangle occupies {} bytes on the heap",
             mem::size_of_val(&boxed_rectangle));
    println!("Boxed box occupies {} bytes on the heap",
             mem::size_of_val(&box_in_a_box));

I increased the variables in Point struct and mades its size 40 bytes on stack but still the Box size is 8 bytes , so in this code . I think the statements should be Boxed point occupies {} bytes on the stack instead of the heap. Basically I am saying that Box is holding an address value of the actual structure and the size of box is 8 bytes which is fixed.

If this is right , can I raise a PR with the Fix ?

@Spoonbender
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I agree - this requires some adjustment.

The size of a box on the stack is the size of a pointer (8 bytes on 64bit machines, 4 bytes on 32Bit machines etc.).
The size of the boxed value on the heap isn't given by mem::size_of_val(&boxed_value)) - that only provides the size of the box itself, since &boxed_value points at the box.

I think we could theoretically fix the heap sized reported by this example using .as_ref():

// box size == pointer size
println!("Boxed point occupies {} bytes on the heap",
             mem::size_of_val(boxed_point.as_ref()));
println!("Boxed rectangle occupies {} bytes on the heap",
             mem::size_of_val(boxed_rectangle.as_ref()));
println!("Boxed box occupies {} bytes on the heap",
             mem::size_of_val(box_in_a_box.as_ref()));

// prints:
// Boxed point occupies 16 bytes on the heap
// Boxed rectangle occupies 32 bytes on the heap
// Boxed box occupies 8 bytes on the heap

but -

  1. The comment // box size == pointer size does imply that this section should demonstrate the size of the Box (the pointer, not the pointed value) - so we probably want to demonstrate that, and just need to fix the text from "heap" to "stack" as you suggest
  2. It could be misleading, given types that hold pointers to other values on the heap - since this technique only measures the size of the pointed value, not that of the entire graph.

So, IMO your proposal is good and you should issue a PR to fix the text.

Abhicodes-crypto added a commit to Abhicodes-crypto/rust-by-example that referenced this issue Oct 21, 2022
compiler-errors added a commit to compiler-errors/rust that referenced this issue Oct 25, 2022
Update books

## reference

4 commits in f6ed74f582bddcec73f753eafaab3749c4f7df61..4ea7c5def38ac81df33a9e48e5637a82a5ac404d
2022-10-08 02:43:26 -0700 to 2022-10-25 15:14:36 -0700
- Document Half Open Range Patterns + Improve Range Patterns in General (rust-lang/reference#1274)
- clarifying which row contains the example (rust-lang/reference#1287)
- Add `sym` operands for inline assembly (rust-lang/reference#1270)
- Add basic GATs reference information (rust-lang/reference#1265)

## book

141 commits in f1e5ad844d0c61738006cdef26227beeb136948e..aa5ee485bd6bd80d205da7c82fcdd776f92fdd51
2022-09-19 09:48:21 -0400 to 2022-10-20 16:49:55 -0400
- Remove Turkish translation
- Update chapter 4 from latest print edits
- Update chapter 3 from latest print edits
- Clarify division truncates toward zero. Fixes rust-lang/book#2856.
- Update chapter 2 from latest print edits
- Fix a problem with literal style ending
- Explain both kinds of format string arguments
- Update chapter 1 from latest print edits
- Snapshot consolidated appendices
- Fix ListNumber0, newlines after lists
- Don't match nodes without anything
- Handle listing numbers in appendices too
- Regenerate everything
- Fix chapter numbers in word doc so they're in the XML
- Number Table captions too
- Handle figures too
- Regenerate ch4
- Handle listing numbers
- Regenerate ch13
- Regenerate ch12
- Regenerate ch11
- Regenerate chapter 10
- Fix ListBullet0
- Handle ending of BoxCode better
- Regenerate chapter 9
- Regenerate ch8
- Make RunInHead consistent-ish
- Fix extra newline before boxes
- Fix Box RunIn Head/Para
- Fix newline after RunInHead/Para
- Regenerate ch7
- Fix QuotePara
- Fix ListPlain
- Regenerate ch6
- Fix BoxCode
- Regenerate chapter 5
- Fix GraphicSlug and CaptionLine
- Regenerate snapshot of chapter 4
- Fix boxes a bit
- Add a shellcheck ignore
- Handle BoxListBullet
- Handle superscript
- Regenerate ch3 from xml and fix tables
- Fix italics and whitespace interactions
- Fix italic preceding/following
- Fix preceding/following xpaths again
- Fix italics
- Fix code blocks
- Fix more last bullets in lists
- Fix box newlines
- Fix last bullet in a list
- Fix BoxType
- Fix notes
- Fix literals
- Add the no editing warning at the top when getting snapshots from docx
- Make the snapshot of the frontmatter nicer
- Updates to appendixes C, D, and E after copyedit checks
- Snapshots after copyedit checks of appendices a and b + recheck of 20
- Snapshot of appendices from copyedit
- Updated snapshot of the appendices
- Re-checks of chapter 19
- Re-checks of chapter 18
- Messy snapshot of chapter 20 after copyedit checks
- Snapshot of ch20 after copyedit
- Updated snapshot of chapter 20
- Messy snapshot of chapter 19 after copyedit checks
- Snapshot of ch19 after copyedit
- Updated snapshot of ch19
- Messy snapshot of ch 18 after copyedit review
- Snapshot of ch 18 after copyedit
- Update snapshot of ch18
- Messy snapshot of ch 17 after copyedit review
- Snapshot of ch17 copyedit
- Updated snapshot of ch17
- Messy snapshot of ch16 after copyedit
- Snapshot of ch16 copyedited
- Updated snapshot of ch16
- Messy snapshot of ch 15 after copyedit checks
- Re-review of earlier chapters
- Snapshot of ch15 copyedit
- Update snapshot of ch15
- Messy snapshots of other chapters with indentation fixed
- Messy snapshot of ch2 with indentation fixed
- Add unittests to the allowed words
- Messy snapshot of chapter 14 after checking copyedit
- Snapshot of chapter 14 after copyedit
- Update snapshot of ch14
- Regenerate manual output for chapter 14
- Messy snapshot of chapter 13 after copyedit check
- Updated snapshot of ch13 after copyedit
- Updated snapshot of ch13
- Messy snapshot of chapter 12 after copyedit checks
- Snapshot of chapter 12 copyedited
- Update snapshot for chapter 12
- Messy snapshot of chapter 11 after copyedit check
- Snapshot of chapter 11 copyedited
- Updated snapshot of chapter 11
- Messy snapshot of chapter 10 after copyedit check
- Snapshot of chapter 10 copyedit
- Updated snapshot of chapter 10
- Messy snapshot of ch9 after copyedit checks
- Snapshot of ch 9 copyedit
- Update snapshot of chapter 9
- Messy snapshot of chapter 8
- Update println style in ch8
- Snapshot of chapter 8 from copyedit
- Updated snapshot of chapter 8
- Rearrange my notes yet again
- Messy snapshot of ch7 after copyedit checks
- Snapshot of chapter 7 from copyedit, fix chapter 6 name
- Update snapshot of chapter 7
- Messy snapshot of chapter 6 after copyedit check
- Update snapshot of chapter 6
- Change my notes again
- Messy snapshot of chapter 5 after checking copyedit
- Snapshot of chapter 5 from copyedit
- Messy snapshot of chapter 4 after copyedit check
- Changing my notes again
- Snapshot of ch4 from nostarch
- Messy snapshot of chapter 3 after copyedit check, ch4 on start check
- Snapshot of ch3 from nostarch
- Updated snapshot of ch3
- reorder notes
- Messy snapshot of chapter 1 after copyedit check
- Snapshot of ch01 docx from nostarch
- Updated snapshot of chapter 1
- Messy snapshot of frontmatter docx
- Another snapshot to fix the crab pinchers description
- Messy snapshot of chapter 2 docx
- Get the latest snapshot of chapter 2
- Upgrade to rand 0.8.5
- Notes to self
- Update xsl and take snapshots from docx, such as they are
- Update instructions on docx -> md now that I've done it again
- Propagate frontmatter edits to src
- Updated snapshots extracted from frontmatter
- Support different styles in the docx
- Line wrap bio
- Frontmatter from word doc
- Edits to docx files for nostarch
- docx files from nostarch

## rust-by-example

6 commits in 5e7b296d6c345addbd748f242aae28c42555c015..03491f33375c5a2a1661c7fa4be671fe95ce1249
2022-10-05 08:24:45 -0300 to 2022-10-21 07:30:08 -0300
- fix rust-lang/rust-by-example#1628: the box pointer is on stack not on heap (rust-lang/rust-by-example#1629)
- fix rust-lang/rust-by-example#1608: out-of-bound indexing is a runtime error (not a compile-time error) (rust-lang/rust-by-example#1626
)
- Fix: Path internal representation and conversions (rust-lang/rust-by-example#1625)
- fix crate name in example (rust-lang/rust-by-example#1620)
- avoid reserved keyword try as crate name (rust-lang/rust-by-example#1619)
- Fix typo in iter_result.md (rust-lang/rust-by-example#1614)

## rustc-dev-guide

7 commits in 7518c34..51a37ad
2022-10-08 12:29:47 +0200 to 2022-10-25 10:18:58 -0700
- Update `traits/resolution.md` (rust-lang/rustc-dev-guide#1494)
- Update diagnostics to flat fluent message paths
- Update rust-analyzer suggestions (rust-lang/rustc-dev-guide#1487)
- miri is no longer a submodule but a subtree. (rust-lang/rustc-dev-guide#1488)
- fix some links (rust-lang/rustc-dev-guide#1490)
- typo and grammar (rust-lang/rustc-dev-guide#1484)
- Add missing prerequisite for some Linux distros (rust-lang/rustc-dev-guide#1481)
Dylan-DPC added a commit to Dylan-DPC/rust that referenced this issue Oct 26, 2022
Update books

## reference

4 commits in f6ed74f582bddcec73f753eafaab3749c4f7df61..4ea7c5def38ac81df33a9e48e5637a82a5ac404d
2022-10-08 02:43:26 -0700 to 2022-10-25 15:14:36 -0700
- Document Half Open Range Patterns + Improve Range Patterns in General (rust-lang/reference#1274)
- clarifying which row contains the example (rust-lang/reference#1287)
- Add `sym` operands for inline assembly (rust-lang/reference#1270)
- Add basic GATs reference information (rust-lang/reference#1265)

## book

141 commits in f1e5ad844d0c61738006cdef26227beeb136948e..aa5ee485bd6bd80d205da7c82fcdd776f92fdd51
2022-09-19 09:48:21 -0400 to 2022-10-20 16:49:55 -0400
- Remove Turkish translation
- Update chapter 4 from latest print edits
- Update chapter 3 from latest print edits
- Clarify division truncates toward zero. Fixes rust-lang/book#2856.
- Update chapter 2 from latest print edits
- Fix a problem with literal style ending
- Explain both kinds of format string arguments
- Update chapter 1 from latest print edits
- Snapshot consolidated appendices
- Fix ListNumber0, newlines after lists
- Don't match nodes without anything
- Handle listing numbers in appendices too
- Regenerate everything
- Fix chapter numbers in word doc so they're in the XML
- Number Table captions too
- Handle figures too
- Regenerate ch4
- Handle listing numbers
- Regenerate ch13
- Regenerate ch12
- Regenerate ch11
- Regenerate chapter 10
- Fix ListBullet0
- Handle ending of BoxCode better
- Regenerate chapter 9
- Regenerate ch8
- Make RunInHead consistent-ish
- Fix extra newline before boxes
- Fix Box RunIn Head/Para
- Fix newline after RunInHead/Para
- Regenerate ch7
- Fix QuotePara
- Fix ListPlain
- Regenerate ch6
- Fix BoxCode
- Regenerate chapter 5
- Fix GraphicSlug and CaptionLine
- Regenerate snapshot of chapter 4
- Fix boxes a bit
- Add a shellcheck ignore
- Handle BoxListBullet
- Handle superscript
- Regenerate ch3 from xml and fix tables
- Fix italics and whitespace interactions
- Fix italic preceding/following
- Fix preceding/following xpaths again
- Fix italics
- Fix code blocks
- Fix more last bullets in lists
- Fix box newlines
- Fix last bullet in a list
- Fix BoxType
- Fix notes
- Fix literals
- Add the no editing warning at the top when getting snapshots from docx
- Make the snapshot of the frontmatter nicer
- Updates to appendixes C, D, and E after copyedit checks
- Snapshots after copyedit checks of appendices a and b + recheck of 20
- Snapshot of appendices from copyedit
- Updated snapshot of the appendices
- Re-checks of chapter 19
- Re-checks of chapter 18
- Messy snapshot of chapter 20 after copyedit checks
- Snapshot of ch20 after copyedit
- Updated snapshot of chapter 20
- Messy snapshot of chapter 19 after copyedit checks
- Snapshot of ch19 after copyedit
- Updated snapshot of ch19
- Messy snapshot of ch 18 after copyedit review
- Snapshot of ch 18 after copyedit
- Update snapshot of ch18
- Messy snapshot of ch 17 after copyedit review
- Snapshot of ch17 copyedit
- Updated snapshot of ch17
- Messy snapshot of ch16 after copyedit
- Snapshot of ch16 copyedited
- Updated snapshot of ch16
- Messy snapshot of ch 15 after copyedit checks
- Re-review of earlier chapters
- Snapshot of ch15 copyedit
- Update snapshot of ch15
- Messy snapshots of other chapters with indentation fixed
- Messy snapshot of ch2 with indentation fixed
- Add unittests to the allowed words
- Messy snapshot of chapter 14 after checking copyedit
- Snapshot of chapter 14 after copyedit
- Update snapshot of ch14
- Regenerate manual output for chapter 14
- Messy snapshot of chapter 13 after copyedit check
- Updated snapshot of ch13 after copyedit
- Updated snapshot of ch13
- Messy snapshot of chapter 12 after copyedit checks
- Snapshot of chapter 12 copyedited
- Update snapshot for chapter 12
- Messy snapshot of chapter 11 after copyedit check
- Snapshot of chapter 11 copyedited
- Updated snapshot of chapter 11
- Messy snapshot of chapter 10 after copyedit check
- Snapshot of chapter 10 copyedit
- Updated snapshot of chapter 10
- Messy snapshot of ch9 after copyedit checks
- Snapshot of ch 9 copyedit
- Update snapshot of chapter 9
- Messy snapshot of chapter 8
- Update println style in ch8
- Snapshot of chapter 8 from copyedit
- Updated snapshot of chapter 8
- Rearrange my notes yet again
- Messy snapshot of ch7 after copyedit checks
- Snapshot of chapter 7 from copyedit, fix chapter 6 name
- Update snapshot of chapter 7
- Messy snapshot of chapter 6 after copyedit check
- Update snapshot of chapter 6
- Change my notes again
- Messy snapshot of chapter 5 after checking copyedit
- Snapshot of chapter 5 from copyedit
- Messy snapshot of chapter 4 after copyedit check
- Changing my notes again
- Snapshot of ch4 from nostarch
- Messy snapshot of chapter 3 after copyedit check, ch4 on start check
- Snapshot of ch3 from nostarch
- Updated snapshot of ch3
- reorder notes
- Messy snapshot of chapter 1 after copyedit check
- Snapshot of ch01 docx from nostarch
- Updated snapshot of chapter 1
- Messy snapshot of frontmatter docx
- Another snapshot to fix the crab pinchers description
- Messy snapshot of chapter 2 docx
- Get the latest snapshot of chapter 2
- Upgrade to rand 0.8.5
- Notes to self
- Update xsl and take snapshots from docx, such as they are
- Update instructions on docx -> md now that I've done it again
- Propagate frontmatter edits to src
- Updated snapshots extracted from frontmatter
- Support different styles in the docx
- Line wrap bio
- Frontmatter from word doc
- Edits to docx files for nostarch
- docx files from nostarch

## rust-by-example

6 commits in 5e7b296d6c345addbd748f242aae28c42555c015..03491f33375c5a2a1661c7fa4be671fe95ce1249
2022-10-05 08:24:45 -0300 to 2022-10-21 07:30:08 -0300
- fix rust-lang/rust-by-example#1628: the box pointer is on stack not on heap (rust-lang/rust-by-example#1629)
- fix rust-lang/rust-by-example#1608: out-of-bound indexing is a runtime error (not a compile-time error) (rust-lang/rust-by-example#1626
)
- Fix: Path internal representation and conversions (rust-lang/rust-by-example#1625)
- fix crate name in example (rust-lang/rust-by-example#1620)
- avoid reserved keyword try as crate name (rust-lang/rust-by-example#1619)
- Fix typo in iter_result.md (rust-lang/rust-by-example#1614)

## rustc-dev-guide

7 commits in 7518c34..51a37ad
2022-10-08 12:29:47 +0200 to 2022-10-25 10:18:58 -0700
- Update `traits/resolution.md` (rust-lang/rustc-dev-guide#1494)
- Update diagnostics to flat fluent message paths
- Update rust-analyzer suggestions (rust-lang/rustc-dev-guide#1487)
- miri is no longer a submodule but a subtree. (rust-lang/rustc-dev-guide#1488)
- fix some links (rust-lang/rustc-dev-guide#1490)
- typo and grammar (rust-lang/rustc-dev-guide#1484)
- Add missing prerequisite for some Linux distros (rust-lang/rustc-dev-guide#1481)
@jon32446
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The code change was merged to master 21 days ago but the docs at https://doc.rust-lang.org/rust-by-example/std/box.html still show the old wording, "Boxed ... occupies {} bytes on the heap". Is this just a matter of waiting a little longer for it to reflect or is there some issue?

@marioidival
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@jon32446 yes, we have a problem... I just contact the infra team to fix that.

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